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Clarke TB, Krushinski LE, Vannoy KJ, Colón-Quintana G, Roy K, Rana A, Renault C, Hill ML, Dick JE. Single Entity Electrocatalysis. Chem Rev 2024; 124:9015-9080. [PMID: 39018111 DOI: 10.1021/acs.chemrev.3c00723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/19/2024]
Abstract
Making a measurement over millions of nanoparticles or exposed crystal facets seldom reports on reactivity of a single nanoparticle or facet, which may depart drastically from ensemble measurements. Within the past 30 years, science has moved toward studying the reactivity of single atoms, molecules, and nanoparticles, one at a time. This shift has been fueled by the realization that everything changes at the nanoscale, especially important industrially relevant properties like those important to electrocatalysis. Studying single nanoscale entities, however, is not trivial and has required the development of new measurement tools. This review explores a tale of the clever use of old and new measurement tools to study electrocatalysis at the single entity level. We explore in detail the complex interrelationship between measurement method, electrocatalytic material, and reaction of interest (e.g., carbon dioxide reduction, oxygen reduction, hydrazine oxidation, etc.). We end with our perspective on the future of single entity electrocatalysis with a key focus on what types of measurements present the greatest opportunity for fundamental discovery.
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Affiliation(s)
- Thomas B Clarke
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Lynn E Krushinski
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kathryn J Vannoy
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | | | - Kingshuk Roy
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ashutosh Rana
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Christophe Renault
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States
| | - Megan L Hill
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jeffrey E Dick
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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2
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Aruchamy G, Kim BK. Recent Trends and Perspectives in Single-Entity Electrochemistry: A Review with Focus on a Water Splitting Reaction. Crit Rev Anal Chem 2024:1-17. [PMID: 38829955 DOI: 10.1080/10408347.2024.2358492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Electrochemical measurements involving single nanoparticles have attracted considerable research attention. In recent years, various studies have been conducted on single-entity electrochemistry (SEE) for the in-depth analyses of catalytic reactions. Although, several electrocatalysts have been developed for H2 energy production, designing innovative electrocatalysts for this purpose remains a challenging task. Stochastic collision electrochemistry is gaining increased attention because it has led to new findings in the SEE field. Importantly, it facilitates establishing structure activity relationships for electrocatalysts by monitoring transient signals. This article reviews the recent achievements related to hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) using different electrocatalysts at the nanoscale level. In particular, it discusses the electrocatalytic activities of noble metal nanoparticles, including Ag, Au, Pt, and Pd nanoparticles, at the single-particle level. Because heterogeneity is a key factor affecting the catalytic activity of nanostructures, our work focuses on the influence of heterogeneities in catalytic materials on the OER and HER activities. These results may help to achieve a better understanding of the fundamental processes involved in the water splitting reaction.
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Affiliation(s)
- Gowrisankar Aruchamy
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, Republic of Korea
| | - Byung-Kwon Kim
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, Republic of Korea
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3
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Pumford A, White RJ. Controlling the Collision Type and Frequency of Single Pt Nanoparticles at Chemically Modified Gold Electrodes. Anal Chem 2024; 96:4800-4808. [PMID: 38470344 DOI: 10.1021/acs.analchem.3c04668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Studying the electrochemical response of single nanoparticles at an electrode surface gives insight into the dynamic and stochastic processes that occur at the electrode interface. Herein, we investigated single platinum nanoparticle collision dynamics and type (elastic vs inelastic) at gold electrode surfaces modified with self-assembled monolayers (SAMs) of varying terminal chemistries. Collision events are measured via the faradaic current from catalytic reactions at the Pt surface. By changing the terminal, solution-facing group of a thiolate monolayer, we observed the effect of hydrophobicity at the solution-electrode interface on single-particle collisions by employing either a hydrophobic -CH3 terminal group (1-hexanethiol), a hydrophilic -OH terminal group (6-mercaptohexanol), or an equimolar mixture of the two. Changes in the terminal group lead to alterations in collision-induced current magnitude, collisional frequency, and the distinct shape of the collision event current transient. The effects of the terminal group of the SAM were probed by measuring quantitative differences in the events monitored through both the hydrogen evolution reaction (HER) and hydrazine oxidation. In both cases, a platinum nanoparticle (PtNP) favors adsorption to bare and hydrophilic surfaces but demonstrates elastic collision behavior when it collides with a hydrophobic surface. In the case of a mixed monolayer, distinct characteristics of hydrophobic and hydrophilic surfaces are observed. We report how single nanoparticle collisions can reveal nanoscale surface heterogeneity and can be used to manipulate the nature of single-particle interactions on an electrode surface by functionalized self-assembled monolayers.
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Affiliation(s)
- Audrey Pumford
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Ryan J White
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, Ohio 45221, United States
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4
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Du M, Zhang L, Meng Y, Chen J, Liu F. Impact of Surface Chemistry on Emulsion-Electrode Interactions and Electron-Transfer Kinetics in the Single-Entity Electrochemistry. Anal Chem 2024; 96:1038-1045. [PMID: 38181449 DOI: 10.1021/acs.analchem.3c03462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
Single-entity electrochemistry (SEE) provides powerful means to track a single particle, single cell, and even single molecule from the nano to microscale. The electrode serves as not only the detector of collision but also the surface supplier in SEE, and the fundamental understanding of the electrode surface chemistry on the dynamic particle-electrode interactions and electrochemical responses of a single particle still remains unexplored, particularly for soft particles. Herein, dynamic interactions of microemulsions and the interaction-controlled electron-transfer (ET) kinetics are studied employing SEE and fluorescence spectroscopy. The o/w-type nitrobenzene emulsions were prepared with the surfactant-type room temperature ionic liquids (RTILs). Biased the electrode potential for the reduction of 7,7,8,8-tetracyanoquinodimethane within emulsions, it is surprising to see the distinct collision current signals on the carbon fiber ultramicroelectrode (C UME) and Au ultramicroelectrode (Au UME) in the late stage of chronoamperometric measurements. Theoretical understanding was made to determine the ET kinetics behind the disparate current signals. It is believed that the electrode surface chemistry, i.e., the surface energy, has a great influence on the dynamic emulsion-electrode interactions and ET kinetics. On the hydrophilic surface of Au UME, emulsions tend to decompose/detach from the electrode surface immediately after colliding. In contrast, on the lipophilic surface of C UME with lower surface energy, a layer of oil phase accumulated by the coalescence of emulsions and the migration of the precedent colliding emulsions, which would serve as a barrier to block ET via tunneling as manifested by the gradual slowdown of ET rate and the reduced collision frequency in the late stage of measurement. The impacts of the emulsion size and amphiphilicity of RTILs on the C UME-emulsion interactions and ET kinetics were also investigated.
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Affiliation(s)
- Minshu Du
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
| | - Lizhu Zhang
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
| | - Yao Meng
- Shaanxi Huaqin New Energy Technology Co., Ltd, Xi'an, Shaanxi 710119, China
| | - Jiajia Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Feng Liu
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
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5
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Lu Y, Ma T, Lan Q, Liu B, Liang X. Single entity collision for inorganic water pollutants measurements: Insights and prospects. WATER RESEARCH 2024; 248:120874. [PMID: 37979571 DOI: 10.1016/j.watres.2023.120874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 10/31/2023] [Accepted: 11/14/2023] [Indexed: 11/20/2023]
Abstract
In the context of aquatic environmental issues, dynamic analysis of nano-sized inorganic water pollutants has been one of the key topics concerning their seriously amplified threat to natural ecosystems and life health. Its ultimate challenge is to reach a single-entity level of identification especially towards substantial amount of inorganic pollutants formed as natural or manufactured nanoparticles (NPs), which enter the water environments along with the potential release of constituents or other contaminating species that may have coprecipitated or adsorbed on the particles' surface. Here, we introduced a 'nano-impacts' approach-single entity collision electrochemistry (SECE) promising for in-situ characterization and quantification of nano-sized inorganic pollutants at single-entity level based on confinement-controlled electrochemistry. In comparison with ensemble analytical tools, advantages and features of SECE point at understanding 'individual' specific fate and effect under its free-motion condition, contributing to obtain more precise information for 'ensemble' nano-sized pollutants on assessing their mixture exposure and toxicity in the environment. This review gives a unique insight about the single-entity collision measurements of various inorganic water pollutants based on recent trends and directions of state-of-the-art single entity electrochemistry, the prospects for exploring nano-impacts in the field of inorganic water pollutants measurements were also put forward.
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Affiliation(s)
- Yuanyuan Lu
- Key Laboratory of Water Pollution Control and Environmental Security Technology, Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Tingting Ma
- Key Laboratory of Water Pollution Control and Environmental Security Technology, Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qingwen Lan
- Key Laboratory of Water Pollution Control and Environmental Security Technology, Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Boyi Liu
- Key Laboratory of Water Pollution Control and Environmental Security Technology, Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xinqiang Liang
- Key Laboratory of Water Pollution Control and Environmental Security Technology, Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
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6
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Qiu X, Dai Q, Tang H, Li Y. Multiplex Assays of MicroRNAs by Using Single Particle Electrochemical Collision in a Single Run. Anal Chem 2023; 95:13376-13384. [PMID: 37603691 DOI: 10.1021/acs.analchem.3c02892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
It is important to quantify multiple biomarkers in a single run due to the advantages of precious samples and diagnostic accuracy. Based on the distinguishability of two types of current signals from single particle electrochemical collision (SPEC), step-type current transients produced by Pt nanoparticles (PtNPs) catalyzed hydrazine oxidation and peak-type current transients produced by Ag nanoparticles (AgNPs) oxidation, a kind of multiplex immunoassay of target microRNAs (miRNA-21 and Let-7a) have been established during SPEC in a single run. When the single-stranded DNA (ssDNA1) that was perfectly complementary to miRNA-21 was coupled to the surface of PtNPs, the SPEC of PtNPs electrocatalysis was inhibited and the step-type current transients disappeared, while the single-stranded DNA (ssDNA2) that was perfectly complementary to Let-7a was coupled to the surface of AgNPs, the SPEC of AgNPs oxidation was inhibited, and the peak-type current transients disappeared, thus the signals were in the "off" state at this time. After that, miRNA-21 and Let-7a were added into solution, complementary base pairing disrupted the weak DNA-NP interaction and restored the electrocatalysis of PtNPs and the electrooxidation of AgNPs, and the step-type current signals and peak-type current signals were in the "on" state. Moreover, the frequencies from two different recovered signals (PtNPs catalysis and AgNPs oxidation) corresponded to the amount of added miRNA-21 and Let-7a, thus a multiplex immunoassay method for dual quantification of miRNA-21 and Let-7a in a single run was established.
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Affiliation(s)
- Xia Qiu
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Qingshan Dai
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Haoran Tang
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Yongxin Li
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, People's Republic of China
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7
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Liu Z, Pishgar S, Lancaster M, Maldonado S. Voltammetric Measurement of Rates and Energetics for Surface Methoxylation of Si(100) in Methanol with Dissolved Electron Acceptors Using Si Ultramicroelectrodes. Anal Chem 2023; 95:6818-6827. [PMID: 37075319 DOI: 10.1021/acs.analchem.2c05276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
The steady-state voltammetric responses of n-type Si(100) semiconductor ultramicroelectrodes (SUMEs) immersed in air- and water-free methanolic electrolytes have been measured. The response characteristics of these SUMEs in the absence of illumination were modeled and understood through a framework that describes the distribution of the applied potential across the semiconductor/electrolyte contact using four discrete regions: the semiconductor space charge, surface, Helmholtz, and diffuse layers. The latter region was described by the full Gouy-Chapman model. This framework afforded insight on how relevant parameters such as the semiconductor band edge potentials, the reorganization energies for charge transfer, the standard potential of redox species in solution, the density and energy of surface state populations, and the presence of an insulating (tunneling) layer individually and collectively dictate the observable current-potential responses. With this information, the methoxylation of Si surfaces was evaluated by analysis of the change in voltammetric responses during the course of prolonged immersion in methanol. The electrochemical data were consistent with a surface methoxylation mechanism that depended on the standard potential of redox species dissolved in solution. Estimates of the enthalpies of adsorption as well as the potential-dependent rate constant for surface methoxylation were obtained. Collectively, these measurements supported the contention that the rates of Si surface reactions can be systematically tuned by exposure to dissolved outer-sphere electron acceptors. Moreover, the data represent the quantitative utility of voltammetry with SUMEs for the measurement of semiconductor/liquid contacts.
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Affiliation(s)
- Zhihui Liu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Sahar Pishgar
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Mitchell Lancaster
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Stephen Maldonado
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- Program in Applied Physics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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8
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Chen R, Liu S, Zhang Y. A nanoelectrode-based study of water splitting electrocatalysts. MATERIALS HORIZONS 2023; 10:52-64. [PMID: 36485037 DOI: 10.1039/d2mh01143c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The development of low-cost and efficient catalytic materials for key reactions like water splitting, CO2 reduction and N2 reduction is crucial for fulfilling the growing energy consumption demands and the pursuit of renewable and sustainable energy. Conventional electrochemical measurements at the macroscale lack the potential to characterize single catalytic entities and nanoscale surface features on the surface of a catalytic material. Recently, promising results have been obtained using nanoelectrodes as ultra-small platforms for the study of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on innovative catalytic materials at the nanoscale. In this minireview, we summarize the recent progress in the nanoelectrode-based studies on the HER and OER on various nanostructured catalytic materials. These electrocatalysts can be generally categorized into two groups: 0-dimensional (0D) single atom/molecule/cluster/nanoparticles and 2-dimensional (2D) nanomaterials. Controlled growth as well as the electrochemical characterization of single isolated atoms, molecules, clusters and nanoparticles has been achieved on nanoelectrodes. Moreover, nanoelectrodes greatly enhanced the spatial resolution of scanning probe techniques, which enable studies at the surface features of 2D nanomaterials, including surface defects, edges and nanofacets at the boundary of a phase. Nanoelectrode-based studies on the catalytic materials can provide new insights into the reaction mechanisms and catalytic properties, which will facilitate the pursuit of sustainable energy and help to solve CO2 release issues.
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Affiliation(s)
- Ran Chen
- Jiangsu Province Key Laboratory of Critical Care Medicine, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
| | - Songqin Liu
- Jiangsu Province Key Laboratory of Critical Care Medicine, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
| | - Yuanjian Zhang
- Jiangsu Province Key Laboratory of Critical Care Medicine, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
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9
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Kurapati N, Janda DC, Balla RJ, Huang SH, Leonard KC, Amemiya S. Nanogap-Resolved Adsorption-Coupled Electron Transfer by Scanning Electrochemical Microscopy: Implications for Electrocatalysis. Anal Chem 2022; 94:17956-17963. [PMID: 36512745 DOI: 10.1021/acs.analchem.2c04008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here, we demonstrate for the first time that the mechanism of adsorption-coupled electron-transfer (ACET) reactions can be identified experimentally. The electron transfer (ET) and specific adsorption of redox-active molecules are coupled in many electrode reactions with practical importance and fundamental interest. ACET reactions are often represented by a concerted mechanism. In reductive adsorption, an oxidant is simultaneously reduced and adsorbed as a reductant on the electrode surface through the ACET step. Alternatively, the non-concerted mechanism mediates outer-sphere reduction and adsorption separately when the reductant adsorption is reversible. In electrocatalysis, reversibly adsorbed reductants are ubiquitous and crucial intermediates. Moreover, electrocatalysis is complicated by the mixed mechanism based on simultaneous ACET and outer-sphere ET steps. In this work, we reveal the non-concerted mechanism for ferrocene derivatives adsorbed at highly oriented pyrolytic graphite as simple models. We enable the transient voltammetric mode of nanoscale scanning electrochemical microscopy (SECM) to kinetically control the adsorption step, which is required for the discrimination of non-concerted, concerted, and mixed mechanisms. Experimental voltammograms are compared with each mechanism by employing finite element simulation. The non-concerted mechanism is supported to indicate that the ACET step is intrinsically slower than its outer-sphere counterpart by at least four orders of magnitude. This finding implies that an ACET step is facilitated thermodynamically but may not be necessarily accelerated or catalyzed by the adsorption of the reductant. SECM-based transient voltammetry will become a powerful tool to resolve and understand electrocatalytic ACET reactions at the elementary level.
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Affiliation(s)
- Niraja Kurapati
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Donald C Janda
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Ryan J Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Siao-Han Huang
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Kevin C Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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10
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Qi J, Wang W, Li Y, Sun Y, Wu Z, Bao K, Wang L, Ye R, Ding M, He Q. On-Chip Investigation of Electrocatalytic Oxygen Reduction Reaction of 2D Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2204010. [PMID: 36251777 DOI: 10.1002/smll.202204010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/22/2022] [Indexed: 06/16/2023]
Abstract
The on-chip electrocatalytic microdevice (OCEM) is an emerging platform specialized in the electrochemical investigation of single-entity nanomaterials, which is ideal for probing the intrinsic catalytic properties, optimizing performance, and exploring exotic mechanisms. However, the current catalytic applications of OCEMs are almost exclusively in electrocatalytic hydrogen/oxygen evolution reactions with minimized influence from the mass transfer. Here, an OCEM platform specially tailored to investigate the electrocatalytic oxygen reduction reaction (ORR) at a microscopic level by introducing electrolyte convection through a microfluidic flow cell is reported. The setup is established on gold microelectrodes and later successfully applied to investigate how Ar-plasma treatment affects the ORR activities of 2H MoS2 . This study finds that Ar-plasma treatment significantly enhances the ORR performance of MoS2 nanosheets owing to the introduction of surface defects. This study paves the way for highly efficient microscopic investigation of diffusion-controlled electrocatalytic reactions.
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Affiliation(s)
- Junlei Qi
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Wenbin Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Yihan Li
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Yamei Sun
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Zongxiao Wu
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Kai Bao
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Lingzhi Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Ruquan Ye
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Mengning Ding
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Qiyuan He
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
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11
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Stable solar water splitting with wettable organic-layer-protected silicon photocathodes. Nat Commun 2022; 13:4460. [PMID: 35915066 PMCID: PMC9343433 DOI: 10.1038/s41467-022-32099-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 07/11/2022] [Indexed: 11/09/2022] Open
Abstract
Protective layers are essential for Si-based photocathodes to achieve long-term stability. The conventionally used inorganic protective layers, such as TiO2, need to be free of pinholes to isolate Si from corrosive solution, which demands extremely high-quality deposition techniques. On the other hand, organic hydrophobic protective layers suffer from the trade-off between current density and stability. This paper describes the design and fabrication of a discontinuous hybrid organic protective layer with controllable surface wettability. The underlying hydrophobic layer induces the formation of thin gas layers at the discontinuous pores to isolate the electrolyte from Si substrate, while allowing Pt co-catalyst to contact the electrolyte for water splitting. Meanwhile, the surface of this organic layer is modified with hydrophilic hydroxyl groups to facilitate bubble detachment. The optimized photocathode achieves a stable photocurrent of 35 mA/cm2 for over 110 h with no trend of decay. Preparation of inorganic protective layers for photoelectrodes requires high-quality deposition techniques. Here, the authors report a spin-coated organic protective layer that enables Si photocathodes to realize stable solar water splitting.
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12
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Majumdar P, Gao R, White HS. Electroprecipitation of Nanometer-Thick Films of Ln(OH) 3 [Ln = La, Ce, and Lu] at Pt Microelectrodes and Their Effect on Electron-Transfer Reactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8125-8134. [PMID: 35715230 DOI: 10.1021/acs.langmuir.2c01008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We report investigations of the deposition of nanometer-thick Ln(OH)3 films (Ln = La, Ce, and Lu) and their effect on outer-sphere and inner-sphere electron-transfer reactions. Insoluble Ln(OH)3 films are deposited from aqueous solutions of LaCl3 onto the surface of 12.5 μm radius Pt microdisk electrodes during water or oxygen reduction. Both reactions produce interfacial OH-, which complexes with Ln3+, resulting in the precipitation of Ln(OH)3. Surface analyses by scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy, and atomic force microscopy indicate the formation of a 1-2 nm thick uniform film. Outer-sphere electron-transfer reactions (Ru(NH3)63+ reduction, FcMeOH oxidation, and Fe(CN)64-/3- oxidation/reduction) were investigated at Ln(OH)3-modified electrodes of different film thicknesses. The results demonstrate that the steady-state transport-limited current for these reactions decreases with an increase in the film thickness. Moreover, the degree of blockage depends upon the redox species, suggesting that the Ln(OH)3 films are free from pinholes greater than the size of the redox molecules. This suggests that the films are either ionically conducting or that electron tunneling occurs across these thin layers. A similar blocking effect was observed for the inner-sphere reductions of H2O and O2. We further demonstrate that the thickness of La(OH)3 films can be controlled by anodic dissolution. Additionally, we show that La3+ lowers the supersaturation of dissolved H2 required to nucleate a stable nanobubble.
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Affiliation(s)
- Pavel Majumdar
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Rui Gao
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Henry S White
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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13
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Wang R, Qian G, Guo J, Ai Q, Liu S, Liu Y, Liang F, Chang S. Nanocollision mediated electrochemical sensing of host-guest chemistry at a nanoelectrode surface. Faraday Discuss 2021; 233:222-231. [PMID: 34889917 DOI: 10.1039/d1fd00054c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrochemical (EC) measurements of dynamic nanoparticle collisions on a support electrode provide a powerful approach to study the electrical properties of interfacial molecules self-assembled on the electrode surface. By introducing a special cage-shaped macrocyclic molecule, cucurbit[7]uril (CB7), onto a gold nanoelectrode surface, we show that the dynamic interactions between CB7 and the colliding nanoparticles can be real-time monitored via the appearance of distinct EC current switching signals. When a guest molecule is included in the CB7 cavity, the changed host-guest chemistry can be probed via the amplitude change of the EC current signals. In addition, different guest molecules can be recognized by CB7 on the nanoelectrode surface, giving rise to distinguishable current jump signals for different host-guest systems. Remarkably, two well-defined current states are observed in the EC measurements of the CB7-ferrocene complex, indicating two orientation geometries of ferrocene inside the CB7 cavity can be resolved in this EC sensing platform. This work demonstrates an effective approach for studying the dynamics of host-guest chemistry at the liquid-solid interface and sheds light on a convenient EC sensor for the recognition of target molecules with the aid of CB7.
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Affiliation(s)
- Ruixia Wang
- The State Key Laboratory of Refractories and Metallurgy, The Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
| | - Gongming Qian
- The State Key Laboratory of Refractories and Metallurgy, The Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
| | - Jing Guo
- The State Key Laboratory of Refractories and Metallurgy, The Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
| | - Qiushuang Ai
- Institute for Quality & Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanchang, Jiangxi 330200, China
| | - Simin Liu
- The State Key Laboratory for Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Yichong Liu
- The State Key Laboratory of Refractories and Metallurgy, The Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
| | - Feng Liang
- The State Key Laboratory for Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Shuai Chang
- The State Key Laboratory of Refractories and Metallurgy, The Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China.
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14
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Sánchez-Álvarez AO, Dick JE, Larios E, Cabrera CR. Anodic coulometry of zero-valent iron nanoparticles. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.115331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Gwon HJ, Lim D, Ahn HS. Bioanalytical chemistry with scanning electrochemical microscopy. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Hyo Jin Gwon
- Department of Chemistry Institution: Yonsei University Seoul South Korea
| | - Donghoon Lim
- Department of Chemistry Institution: Yonsei University Seoul South Korea
| | - Hyun S. Ahn
- Department of Chemistry Institution: Yonsei University Seoul South Korea
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16
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Hou S, Kluge RM, Haid RW, Gubanova EL, Watzele SA, Bandarenka AS, Garlyyev B. A Review on Experimental Identification of Active Sites in Model Bifunctional Electrocatalytic Systems for Oxygen Reduction and Evolution Reactions. ChemElectroChem 2021. [DOI: 10.1002/celc.202100584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shujin Hou
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
- Catalysis Research Center TUM Ernst-Otto-Fischer-Str. 1 85748 Garching bei München Germany
| | - Regina M. Kluge
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
| | - Richard W. Haid
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
| | - Elena L. Gubanova
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
| | - Sebastian A. Watzele
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
| | - Aliaksandr S. Bandarenka
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
- Catalysis Research Center TUM Ernst-Otto-Fischer-Str. 1 85748 Garching bei München Germany
| | - Batyr Garlyyev
- Physics of Energy Conversion and Storage Physik-Department Technische Universität München James-Franck-Str. 1 85748 Garching bei München Germany
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17
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Lu SM, Chen JF, Peng YY, Ma W, Ma H, Wang HF, Hu P, Long YT. Understanding the Dynamic Potential Distribution at the Electrode Interface by Stochastic Collision Electrochemistry. J Am Chem Soc 2021; 143:12428-12432. [PMID: 34347459 DOI: 10.1021/jacs.1c02588] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The potential distribution at the electrode interface is a core factor in electrochemistry, and it is usually treated by the classic Gouy-Chapman-Stern (G-C-S) model. Yet the G-C-S model is not applicable to nanosized particles collision electrochemistry as it describes steady-state electrode potential distribution. Additionally, the effect of single nanoparticles (NPs) on potential should not be neglected because the size of a NP is comparable to that of an electrode. Herein, a theoretical model termed as Metal-Solution-Metal Nanoparticle (M-S-MNP) is proposed to reveal the dynamic electrode potential distribution at the single-nanoparticle level. An explicit equation is provided to describe the size/distance-dependent potential distribution in single NPs stochastic collision electrochemistry, showing the potential distribution is influenced by the NPs. Agreement between experiments and simulations indicates the potential roles of the M-S-MNP model in understanding the charge transfer process at the nanoscale.
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Affiliation(s)
- Si-Min Lu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.,School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Jian-Fu Chen
- State Key Laboratory of Chemical Engineering, Centre for Computational Chemistry & Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Yue-Yi Peng
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.,School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Wei Ma
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Hui Ma
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.,School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Hai-Feng Wang
- State Key Laboratory of Chemical Engineering, Centre for Computational Chemistry & Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Peijun Hu
- State Key Laboratory of Chemical Engineering, Centre for Computational Chemistry & Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, P. R. China.,School of Chemistry and Chemical Engineering, The Queen's University of Belfast, Belfast BT9 5AG, U.K
| | - Yi-Tao Long
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.,School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
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18
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Kong N, Guo J, Chang S, Pan J, Wang J, Zhou J, Liu J, Zhou H, Pfeffer FM, Liu J, Barrow CJ, He J, Yang W. Direct Observation of Amide Bond Formation in a Plasmonic Nanocavity Triggered by Single Nanoparticle Collisions. J Am Chem Soc 2021; 143:9781-9790. [PMID: 34164979 DOI: 10.1021/jacs.1c02426] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The real-time observation of chemical bond formation at the single-molecule level is one of the great challenges in the fields of organic and biomolecular chemistry. Valuable information can be gleaned that is not accessible using ensemble-average measurements. Although remarkably sophisticated techniques for monitoring chemical reactions have been developed, the ability to detect the specific formation of a chemical bond in situ at the single-molecule level has remained an elusive goal. Amide bonds are routinely formed from the aminolysis of N-hydroxysuccinimide (NHS) esters by primary amines, and the protocol is widely used for the synthesis, cross-linking, and labeling of peptides and proteins. Herein, a plasmonic nanocavity was applied to study aminolysis reaction for amide bond formation, which was initiated by single nanoparticle collision events between suitably functionalized free-moving gold nanoparticles and a gold nanoelectrode in an aqueous buffer. By means of simultaneous surface enhanced Raman spectroscopy (SERS) and single-entity electrochemistry (EC) measurements, we have probed the dynamic evolution of amide bond formation in the aminolysis reaction with 10 s of millisecond time resolution. Hence, we demonstrate that single-entity EC-SERS is a valuable and sensitive technique by which chemical reactions can be studied at the single-molecule level.
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Affiliation(s)
- Na Kong
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia.,Department of Physics, Florida International University, Miami, Florida 33199, United States
| | - Jing Guo
- Department of Physics, Florida International University, Miami, Florida 33199, United States
| | - Shuai Chang
- The State Key Laboratory of Refractories and Metallurgy, the Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Jie Pan
- Department of Physics, Florida International University, Miami, Florida 33199, United States
| | - Jianmei Wang
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia
| | - Jianghao Zhou
- Department of Physics, Florida International University, Miami, Florida 33199, United States.,The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Jing Liu
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia.,Shandong Province Key Laboratory of Detection Technology for Tumor Markers, Linyi University, Linyi, Shandong 276005, P. R. China
| | - Hong Zhou
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia.,Shandong Province Key Laboratory of Detection Technology for Tumor Markers, Linyi University, Linyi, Shandong 276005, P. R. China
| | - Frederick M Pfeffer
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia
| | - Jingquan Liu
- College of Material Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, Qingdao 266071, China
| | - Colin J Barrow
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia
| | - Jin He
- Department of Physics, Florida International University, Miami, Florida 33199, United States.,Biomolecular Science Institute, Florida International University, Miami, Florida 33199, United States
| | - Wenrong Yang
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3216, Australia
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19
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A Review: Scanning Electrochemical Microscopy (SECM) for Visualizing the Real-Time Local Catalytic Activity. Catalysts 2021. [DOI: 10.3390/catal11050594] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Scanning electrochemical microscopy (SECM) is a powerful scanning probe technique for measuring the in situ electrochemical reactions occurring at various sample interfaces, such as the liquid-liquid, solid-liquid, and liquid-gas. The tip/probe of SECM is usually an ultramicroelectrode (UME) or a nanoelectrode that can move towards or over the sample of interest controlled by a precise motor positioning system. Remarkably, electrocatalysts play a crucial role in addressing the surge in global energy consumption by providing sustainable alternative energy sources. Therefore, the precise measurement of catalytic reactions offers profound insights for designing novel catalysts as well as for enhancing their performance. SECM proves to be an excellent tool for characterization and screening catalysts as the probe can rapidly scan along one direction over the sample array containing a large number of different compositions. These features make SECM more appealing than other conventional methodologies for assessing bulk solutions. SECM can be employed for investigating numerous catalytic reactions including the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), water oxidation, glucose oxidation reaction (GOR), and CO2 reduction reaction (CO2RR) with high spatial resolution. Moreover, for improving the catalyst design, several SECM modes can be applied based on the catalytic reactions under evaluation. This review aims to present a brief overview of the recent applications of electrocatalysts and their kinetics as well as catalytic sites in electrochemical reactions, such as oxygen reduction, water oxidation, and methanol oxidation.
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20
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Lee J, Lee J, Song S, Kim B. Single Microcystis Detection Through Electrochemical Collision Events on Ultramicroelectrodes. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jeeho Lee
- Department of Chemistry Sookmyung Women's University Seoul 04310 South Korea
| | - Jungeun Lee
- Department of Chemistry Sookmyung Women's University Seoul 04310 South Korea
| | - Sua Song
- Department of Chemistry Sookmyung Women's University Seoul 04310 South Korea
| | - Byung‐Kwon Kim
- Department of Chemistry Sookmyung Women's University Seoul 04310 South Korea
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21
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Wang B, Biesold GM, Zhang M, Lin Z. Amorphous inorganic semiconductors for the development of solar cell, photoelectrocatalytic and photocatalytic applications. Chem Soc Rev 2021; 50:6914-6949. [PMID: 33904560 DOI: 10.1039/d0cs01134g] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Amorphous inorganic semiconductors have attracted growing interest due to their unique electrical and optical properties that arise from their intrinsic disordered structure and thermodynamic metastability. Recently, amorphous inorganic semiconductors have been applied in a variety of new technologies, including solar cells, photoelectrocatalysis, and photocatalysis. It has been reported that amorphous phases can improve both efficiency and stability in these applications. While these phenomena are well established, their mechanisms have long remained unclear. This review first introduces the general background of amorphous inorganic semiconductor properties and synthesis. Then, the recent successes and current challenges of amorphous inorganic semiconductor-based materials for applications in solar cells, photoelectrocatalysis, and photocatalysis are addressed. In particular, we discuss the mechanisms behind the remarkable performances of amorphous inorganic semiconductors in these fields. Finally, we provide insightful perspectives into further developments for applications of amorphous inorganic semiconductors.
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Affiliation(s)
- Bing Wang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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22
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Wang H, Yang C, Tang H, Li Y. Stochastic Collision Electrochemistry from Single G-Quadruplex/Hemin: Electrochemical Amplification and MicroRNA Sensing. Anal Chem 2021; 93:4593-4600. [PMID: 33660976 DOI: 10.1021/acs.analchem.0c05055] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Stochastic collision electrochemistry is a hot topic in single molecule/particle research, which provides an opportunity to investigate the details of the single molecule/particle reaction mechanism that is always masked in ensemble-averaged measurements. In this work, we develop an electrochemical amplification strategy to monitor the electrocatalytic behavior of single G-quadruplex/hemin (GQH) for the reaction between hydrogen peroxide and hydroquinone (HQ) through the collision upon a gold nanoelectrode. The intrinsic peroxidase activities of single GQH were investigated by stochastic collision electrochemical measurements, giving further insights into understanding biocatalytic processes. Based on the unique catalytic activity of GQH, we have also designed a hybridization chain reaction strategy to detect miRNA-15 with good selectivity and sensitivity. This work provided a meaningful strategy to investigate the electrochemical amplification and the broad application for nucleic acid sensing at the single molecule/particle level.
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Affiliation(s)
- Hao Wang
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, P. R. China
| | - Cheng Yang
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, P. R. China
| | - Haoran Tang
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, P. R. China
| | - Yongxin Li
- Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, P. R. China
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23
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Gutierrez-Portocarrero S, Sauer K, Karunathilake N, Subedi P, Alpuche-Aviles MA. Digital Processing for Single Nanoparticle Electrochemical Transient Measurements. Anal Chem 2020; 92:8704-8714. [PMID: 32510201 DOI: 10.1021/acs.analchem.9b05238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We demonstrate the use of digital frequency analysis in single nanoparticle electrochemical detection. The method uses fast Fourier transforms (FFT) of single entity electrochemical transients and digital filters. These filters effectively remove noise with the Butterworth filter preserving the amplitude of the fundamental processes in comparison with the rectangle filter. Filtering was done in three different types of experiments: single nanoparticle electrocatalytic amplification, photocatalytic amplification, and nanoimpacts of single entities. In the individual nanoparticle stepwise transients, low-pass filters maintain the step height. Furthermore, a Butterworth band-stop filter preserves the peak height in blip transients if the band-stop cutoff frequencies are compatible with the nanoparticle/electrode transient interactions. In hydrazine oxidation by single Au nanoparticles, digital filtering does not complicate the analysis of the step signal because the stepwise change of the particle-by-particle current is preserved with the rectangle, Bessel and Butterworth low pass filters, with the later minimizing time shifts. In the photocurrent single entity transients, we demonstrate resolving a step smaller than the noise. In photoelectrochemical setups, the background processes are stochastic and appear at distinct frequencies that do not necessarily correlate with the detection frequency (fp), of TiO2 nanoparticles. This lack of correlation indicates that background signals have their characteristic frequencies and that it is advantageous to perform filtering a posteriori. We also discuss selecting the filtering frequencies based on sampling rates and fp. In experiments electrolyzing ZnO, that model nanoimpacts, a band-stop filter can remove environmental noise within the sampling spectral region while preserving relevant information on the current transient. We discuss the limits of Bessel and Butterworth filters for resolving consecutive transients.
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Affiliation(s)
| | - Kiley Sauer
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, United States
| | - Nelum Karunathilake
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, United States
| | - Pradeep Subedi
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, United States
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24
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Ai Q, Jin L, Gong Z, Liang F. Observing Host-Guest Interactions at Molecular Interfaces by Monitoring the Electrochemical Current. ACS OMEGA 2020; 5:10581-10585. [PMID: 32426616 PMCID: PMC7227043 DOI: 10.1021/acsomega.0c01077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/21/2020] [Indexed: 05/08/2023]
Abstract
Macrocyclic cucurbit[n]uril (CB[n]) molecules have triggered renewed interest because of their outstanding capabilities as host molecules to selectively interact with a wide range of small guest molecules. Here, CB[7]-based host-guest interactions were investigated for a guest-modified nanoelectrode by monitoring the electrochemical current. A ferrocene (Fc)-terminated molecule immobilized on a gold nanoelectrode (GNE) showed suitable affinity with CB[7] when the effective exposing area of the GNE was between 5.3 and 12 μm2 and the bias applied on the GNE was -500 mV. Monitoring the dynamics of nanoparticles (NPs) on a nanoelectrode provides new insights into the host-guest interactions at molecular interfaces.
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25
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Ying YL, Wang J, Leach AR, Jiang Y, Gao R, Xu C, Edwards MA, Pendergast AD, Ren H, Weatherly CKT, Wang W, Actis P, Mao L, White HS, Long YT. Single-entity electrochemistry at confined sensing interfaces. Sci China Chem 2020. [DOI: 10.1007/s11426-020-9716-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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26
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An ultrasensitive photoelectrochemical platform for quantifying photoinduced electron-transfer properties of a single entity. Nat Protoc 2019; 14:2672-2690. [PMID: 31391579 DOI: 10.1038/s41596-019-0197-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 05/15/2019] [Indexed: 02/06/2023]
Abstract
Understanding the photoinduced electron-transfer process is of paramount importance for realizing efficient solar energy conversion. It is rather difficult to clarify the link between the specific properties and the photoelectrochemical performance of an individual component in an ensemble system because data are usually presented as averages because of interplay of the heterogeneity of the bulk system. Here, we report a step-by-step protocol to fabricate an ultrasensitive photoelectrochemical platform for real-time detection of the intrinsic photoelectrochemical behaviors of a single entity with picoampere and sub-millisecond sensitivity. Using a micron-thickness nanoparticulate TiO2-filmed Au ultramicroelectrode (UME) as the electron-transport electrode, photocurrent transients can be observed for each individual dye-tagged oxide semiconductor nanoparticle collision associated with a single-entity photoelectrochemical reaction. This protocol allows researchers to obtain high-resolution photocurrent signals to quantify the photoinduced electron-transfer properties of an individual entity, as well as to precisely process the data obtained. We also include procedures for dynamic light scattering (DLS) analysis, transmission electron microscopy (TEM) imaging and collision frequency-concentration correlation to confirm that the photoelectrochemical collision events occur at an unambiguously single-entity level. The time required for the entire protocol is ~36 h, with a single-entity photoelectrochemical measurement taking <1 h to complete for each independent experiment. This protocol requires basic nanoelectrochemistry and nanotechnology skills, as well as an intermediate-level understanding of photoelectrochemistry.
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27
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Balla RJ, Jantz DT, Kurapati N, Chen R, Leonard KC, Amemiya S. Nanoscale Intelligent Imaging Based on Real-Time Analysis of Approach Curve by Scanning Electrochemical Microscopy. Anal Chem 2019; 91:10227-10235. [PMID: 31310104 DOI: 10.1021/acs.analchem.9b02361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Scanning electrochemical microscopy (SECM) enables high-resolution imaging by examining the amperometric response of an ultramicroelectrode tip near a substrate. Spatial resolution, however, is compromised for nonflat substrates, where distances from a tip far exceed the tip size to avoid artifacts caused by the tip-substrate contact. Herein, we propose a new imaging mode of SECM based on real-time analysis of the approach curve to actively control nanoscale tip-substrate distances without contact. The power of this software-based method is demonstrated by imaging an insulating substrate with step edges using standard instrumentation without combination of another method for distance measurement, e.g., atomic force microscopy. An ∼500 nm diameter Pt tip approaches down to ∼50 nm from upper and lower terraces of a 500 nm height step edge, which are located by real-time theoretical fitting of an experimental approach curve to ensure the lack of electrochemical reactivity. The tip approach to the step edge can be terminated at <20 nm prior to the tip-substrate contact as soon as the theory deviates from the tip current, which is analyzed numerically afterward to locate the inert edge. The advantageous local adjustment of tip height and tip current at the final point of tip approach distinguishes the proposed imaging mode from other modes based on standard instrumentation. In addition, the glass sheath of the Pt tip is thinned to ∼150 nm to rarely contact the step edge, which is unavoidable and instantaneously detected as an abrupt change in the slope of approach curve to prevent damage of the fragile nanotip.
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Affiliation(s)
- Ryan J Balla
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Dylan T Jantz
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering , University of Kansas , 1501 Wakarusa Drive , Lawrence , Kansas 66047 , United States
| | - Niraja Kurapati
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Ran Chen
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Kevin C Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering , University of Kansas , 1501 Wakarusa Drive , Lawrence , Kansas 66047 , United States
| | - Shigeru Amemiya
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
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28
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Karimi A, Andreescu S, Andreescu D. Single-Particle Investigation of Environmental Redox Processes of Arsenic on Cerium Oxide Nanoparticles by Collision Electrochemistry. ACS APPLIED MATERIALS & INTERFACES 2019; 11:24725-24734. [PMID: 31190542 DOI: 10.1021/acsami.9b05234] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Quantification of chemical reactions of nanoparticles (NPs) and their interaction with contaminants is a fundamental need to the understanding of chemical reactivity and surface chemistry of NPs released into the environment. Herein, we propose a novel strategy employing single-particle electrochemistry showing that it is possible to measure reactivity, speciation, and loading of As3+ on individual NPs, using cerium oxide (CeO2) as a model system. We demonstrate that redox reactions and adsorption processes can be electrochemically quantified with high sensitivity via the oxidation of As3+ to As5+ at 0.8 V versus Ag/AgCl or the reduction of As3+ to As0 at -0.3 V (vs Ag/AgCl) generated by collisions of single particles at an ultramicroelectrode. Using collision electrochemistry, As3+ concentrations were determined in basic conditions showing a maximum adsorption capacity at pH 8. In acidic environments (pH < 4), a small fraction of As3+ was oxidized to As5+ by surface Ce4+ and further adsorbed onto the CeO2 surface as a As5+ bidentate complex. The frequency of current spikes (oxidative or reductive) was proportional to the concentration of As3+ accumulated onto the NPs and was found to be representative of the As3+ concentration in solution. Given its sensitivity and speciation capability, the method can find many applications in the analytical, materials, and environmental chemistry fields where there is a need to quantify the reactivity and surface interactions of NPs. This is the first study demonstrating the capability of single-particle collision electrochemistry to monitor the interaction of heavy metal ions with metal oxide NPs. This knowledge is critical to the fundamental understanding of the risks associated with the release of NPs into the environment for their safe implementation and practical use.
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Affiliation(s)
- Anahita Karimi
- Department of Chemistry and Biomolecular Science , Clarkson University , Potsdam , New York 13699-5810 , United States
| | - Silvana Andreescu
- Department of Chemistry and Biomolecular Science , Clarkson University , Potsdam , New York 13699-5810 , United States
| | - Daniel Andreescu
- Department of Chemistry and Biomolecular Science , Clarkson University , Potsdam , New York 13699-5810 , United States
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29
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Chen G, Wang X, Wang S, Song L. Retrieving the Lost Information of Au Aggregated Nanoparticles during Electrode Collision on an Inverted Ultramicroelectrode. CHEM LETT 2019. [DOI: 10.1246/cl.190110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Gaoli Chen
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
- College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Xiaolong Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Song Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Lei Song
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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30
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Qiao W, Tao HB, Liu B, Chen J. Nanostructuring Confinement for Controllable Interfacial Charge Transfer. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804391. [PMID: 30663213 DOI: 10.1002/smll.201804391] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Carbon nanostructures supported semiconductors are common in photocatalytic and photoelectrochemical applications, as it is expected that the nanoconductors can improve the spatial separation and transport of photogenerated charge carriers. Transfer of charge carriers through the carbon-semiconductor interface is the key electronic process, which determines the role of charge separation channels, and is sensitively influenced by band structures of the semiconductor near the contacts. Usually, this electronic process suffers from excessive energy dissipation by thermionic emission, which will undesirably prevent the interfacial charge transfer and eventually aggravate the recombination of photogenerated charge carriers. Unfortunately, this critical issue has hardly been consciously considered. Here, ultrathin dopant-free tunneling interlayers coated on the surface of graphene and sandwiched between the carbon sheets and the semiconductor nanostructures are adopted as a model system to demonstrate energy saving for the interfacial charge transfer. The nanostructuring confinement of band bending within the ultrathin interlayers in contact with the graphene sheets effectively narrows the width of the potential barriers, which enables tunneling of a substantial number of photogenerated electrons to the co-catalysts without unduly consuming energy. Besides, the dopant-free tunneling interlayers simultaneously block the transferred electrons in the sandwiched graphene sheets from leakage.
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Affiliation(s)
- Wei Qiao
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459, Singapore
| | - Hua Bing Tao
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bin Liu
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiazang Chen
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China
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31
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Patrice FT, Qiu K, Ying YL, Long YT. Single Nanoparticle Electrochemistry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2019; 12:347-370. [PMID: 31018101 DOI: 10.1146/annurev-anchem-061318-114902] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Experimental techniques to monitor and visualize the behaviors of single nanoparticles have not only revealed the significant spatial and temporal heterogeneity of those individuals, which are hidden in ensemble methods, but more importantly, they have also enabled researchers to elucidate the origin of such heterogeneity. In pursuing the intrinsic structure-function relations of single nanoparticles, the recently developed stochastic collision approach demonstrated some early promise. However, it was later realized that the appropriate sizing of a single nanoparticle by an electrochemical method could be far more challenging than initially expected owing to the dynamic motion of nanoparticles in electrolytes and complex charge-transfer characteristics at electrode surfaces. This clearly indicates a strong necessity to integrate single nanoparticle electrochemistry with high-resolution optical microscopy. Hence, this review aims to give a timely update of the latest progress for both electrochemically sensing and seeing single nanoparticles. A major focus is on collision-based measurements, where nanoparticles or single entities in solution impact on a collector electrode and the electrochemical response is recorded. These measurements are further enhanced with optical measurements in parallel. For completeness, advances in other related methods for single nanoparticle electrochemistry are also included.
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Affiliation(s)
- Fato Tano Patrice
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; ;
| | - Kaipei Qiu
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; ;
| | - Yi-Lun Ying
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; ;
| | - Yi-Tao Long
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; ;
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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Pathirathna P, Balla RJ, Jantz DT, Kurapati N, Gramm ER, Leonard KC, Amemiya S. Probing High Permeability of Nuclear Pore Complexes by Scanning Electrochemical Microscopy: Ca 2+ Effects on Transport Barriers. Anal Chem 2019; 91:5446-5454. [PMID: 30907572 PMCID: PMC6535230 DOI: 10.1021/acs.analchem.9b00796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The nuclear pore complex (NPC) solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell to play important biological and biomedical roles. However, it is not well-understood chemically how this biological nanopore selectively and efficiently transports various substances, including small molecules, proteins, and RNAs by using transport barriers that are rich in highly disordered repeats of hydrophobic phenylalanine and glycine intermingled with charged amino acids. Herein, we employ scanning electrochemical microscopy to image and measure the high permeability of NPCs to small redox molecules. The effective medium theory demonstrates that the measured permeability is controlled by diffusional translocation of probe molecules through water-filled nanopores without steric or electrostatic hindrance from hydrophobic or charged regions of transport barriers, respectively. However, the permeability of NPCs is reduced by a low millimolar concentration of Ca2+, which can interact with anionic regions of transport barriers to alter their spatial distributions within the nanopore. We employ atomic force microscopy to confirm that transport barriers of NPCs are dominantly recessed (∼80%) or entangled (∼20%) at the high Ca2+ level in contrast to authentic populations of entangled (∼50%), recessed (∼25%), and "plugged" (∼25%) conformations at a physiological Ca2+ level of submicromolar. We propose a model for synchronized Ca2+ effects on the conformation and permeability of NPCs, where transport barriers are viscosified to lower permeability. Significantly, this result supports a hypothesis that the functional structure of transport barriers is maintained not only by their hydrophobic regions, but also by charged regions.
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Affiliation(s)
- Pavithra Pathirathna
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Ryan J. Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Dylan T. Jantz
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Niraja Kurapati
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Erin R. Gramm
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Kevin C. Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
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33
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OKAWA H, MAKI H, MIZUHATA M. Influence of Immersion of Polyethyleneimine Thin Film Modified with Gold Nanoparticles in [Ru(NH<sub>3</sub>)<sub>6</sub>]Cl<sub>3</sub> Aqueous Solution on Redox Reaction on AuNPs. ELECTROCHEMISTRY 2019. [DOI: 10.5796/electrochemistry.18-00090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hiroyuki OKAWA
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University
| | - Hideshi MAKI
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University
- Center for Environmental Management, Kobe University
| | - Minoru MIZUHATA
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University
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34
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Direct Electrolysis and Detection of Single Nanosized Water Emulsion Droplets in Organic Solvent Using Stochastic Collisions. ELECTROANAL 2018. [DOI: 10.1002/elan.201800726] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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35
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Chen R, Najarian AM, Kurapati N, Balla RJ, Oleinick A, Svir I, Amatore C, McCreery RL, Amemiya S. Self-Inhibitory Electron Transfer of the Co(III)/Co(II)-Complex Redox Couple at Pristine Carbon Electrode. Anal Chem 2018; 90:11115-11123. [PMID: 30118206 DOI: 10.1021/acs.analchem.8b03023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Applications of conducting carbon materials for highly efficient electrochemical energy devices require a greater fundamental understanding of heterogeneous electron-transfer (ET) mechanisms. This task, however, is highly challenging experimentally, because an adsorbing carbon surface may easily conceal its intrinsic reactivity through adventitious contamination. Herein, we employ nanoscale scanning electrochemical microscopy (SECM) and cyclic voltammetry to gain new insights into the interplay between heterogeneous ET and adsorption of a Co(III)/Co(II)-complex redox couple at the contamination-free surface of electron-beam-deposited carbon (eC). Specifically, we investigate the redox couple of tris(1,10-phenanthroline)cobalt(II), Co(phen)32+, as a promising mediator for dye-sensitized solar cells and redox flow batteries. A pristine eC surface overlaid with KCl is prepared in vacuum, protected from contamination in air, and exposed to an ultrapure aqueous solution of Co(phen)32+ by the dissolution of the protective KCl layer. We employ SECM-based nanogap voltammetry to quantitatively demonstrate that Co(phen)32+ is adsorbed on the pristine eC surface to electrostatically self-inhibit outer-sphere ET of nonadsorbed Co(phen)33+ and Co(phen)32+. Strong electrostatic repulsion among Co(phen)32+ adsorbates is also demonstrated by SECM-based nanogap voltammetry and cyclic voltammetry. Quantitatively, self-inhibitory ET is characterized by a linear decrease in the standard rate constant of Co(phen)32+ oxidation with a higher surface concentration of Co(phen)32+ at the formal potential. This unique relationship is consistent not with the Frumkin model of double layer effects, but with the Amatore model of partially blocked electrodes as extended for self-inhibitory ET. Significantly, the complicated coupling of electron transfer and surface adsorption is resolved by combining nanoscale and macroscale voltammetric methods.
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Affiliation(s)
- Ran Chen
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Amin Morteza Najarian
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Niraja Kurapati
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Ryan J Balla
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
| | - Alexander Oleinick
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France
| | - Irina Svir
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France
| | - Christian Amatore
- PASTEUR, Département de Chimie , École Normale Supérieure, PSL Université, Sorbonne Université , CNRS, 75005 Paris , France.,State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen , 361005 , China
| | - Richard L McCreery
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Shigeru Amemiya
- Department of Chemistry , University of Pittsburgh , 219 Parkman Avenue , Pittsburgh , Pennsylvania 15260 , United States
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36
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Barakoti KK, Parajuli S, Chhetri P, Rana GR, Kazemi R, Malkiewich R, Alpuche-Aviles MA. Stochastic electrochemistry and photoelectrochemistry of colloidal dye-sensitized anatase nanoparticles at a Pt ultramicroelectrode. Faraday Discuss 2018; 193:313-325. [PMID: 27711900 DOI: 10.1039/c6fd00100a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the stochastic interactions between dye sensitized anatase nanoparticles, suspended in a colloid, and a Pt ultramicroelectrode (UME) that result in step-wise behavior in the current vs. time response. The stochastic currents are observed in the dark and under illumination. In the dark, the currents are anodic, consistent with the oxidation of the dye N719 at the Pt surface. The electrochemical behavior of the dye was investigated in MeOH and MeCN with a quasireversible cyclic voltammogram (CV) observed at 1 V s-1. The anodic currents observed in the dark due to nanoparticles (NPs) at the Pt surface are consistent with the CVs in MeOH and MeCN. Under illumination cathodic steps are observed and assigned to the reduction of the oxidized form of the dye generated after electrons are injected into the TiO2 NPs. The colloidal behavior is a strong function of the history of the colloid with illumination time increasing the size of the agglomerates and with larger agglomerates being less photoelectrochemically active. Agglomerates of ca. 100 nm in diameter are proposed to be photoactive entities with a higher probability of detection that contribute to the staircase photocurrent response.
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Affiliation(s)
| | - Suman Parajuli
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Pushpa Chhetri
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Ganesh R Rana
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Rezvan Kazemi
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Ryan Malkiewich
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
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37
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Wang Y, Shan X, Tao N. Emerging tools for studying single entity electrochemistry. Faraday Discuss 2018; 193:9-39. [PMID: 27722354 DOI: 10.1039/c6fd00180g] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Electrochemistry studies charge transfer and related processes at various microscopic structures (atomic steps, islands, pits and kinks on electrodes), and mesoscopic materials (nanoparticles, nanowires, viruses, vesicles and cells) made by nature and humans, involving ions and molecules. The traditional approach measures averaged electrochemical quantities of a large ensemble of these individual entities, including the microstructures, mesoscopic materials, ions and molecules. There is a need to develop tools to study single entities because a real system is usually heterogeneous, e.g., containing nanoparticles with different sizes and shapes. Even in the case of "homogeneous" molecules, they bind to different microscopic structures of an electrode, assume different conformations and fluctuate over time, leading to heterogeneous reactions. Here we highlight some emerging tools for studying single entity electrochemistry, discuss their strengths and weaknesses, and provide personal views on the need for tools with new capabilities for further advancing single entity electrochemistry.
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Affiliation(s)
- Yixian Wang
- Center for Biosensors and Bioelectronics, Biodesign Institute and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
| | - Xiaonan Shan
- Center for Biosensors and Bioelectronics, Biodesign Institute and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
| | - Nongjian Tao
- Center for Biosensors and Bioelectronics, Biodesign Institute and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA. and State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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38
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Glasscott MW, Dick JE. Direct Electrochemical Observation of Single Platinum Cluster Electrocatalysis on Ultramicroelectrodes. Anal Chem 2018; 90:7804-7808. [DOI: 10.1021/acs.analchem.8b02219] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Matthew W. Glasscott
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jeffrey E. Dick
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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39
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Sun T, Wang D, Mirkin MV. Tunneling Mode of Scanning Electrochemical Microscopy: Probing Electrochemical Processes at Single Nanoparticles. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Tong Sun
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
- The Graduate Center of CUNY New York NY 10016 USA
| | - Dengchao Wang
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
| | - Michael V. Mirkin
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
- The Graduate Center of CUNY New York NY 10016 USA
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40
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Sun T, Wang D, Mirkin MV. Tunneling Mode of Scanning Electrochemical Microscopy: Probing Electrochemical Processes at Single Nanoparticles. Angew Chem Int Ed Engl 2018; 57:7463-7467. [DOI: 10.1002/anie.201801115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/24/2018] [Indexed: 11/05/2022]
Affiliation(s)
- Tong Sun
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
- The Graduate Center of CUNY New York NY 10016 USA
| | - Dengchao Wang
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
| | - Michael V. Mirkin
- Department of Chemistry and Biochemistry Queens College-CUNY Flushing NY 11367 USA
- The Graduate Center of CUNY New York NY 10016 USA
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41
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Guo J, Pan J, Chang S, Wang X, Kong N, Yang W, He J. Monitoring the Dynamic Process of Formation of Plasmonic Molecular Junctions during Single Nanoparticle Collisions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1704164. [PMID: 29493086 DOI: 10.1002/smll.201704164] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/21/2018] [Indexed: 05/23/2023]
Abstract
The capability to study the dynamic formation of plasmonic molecular junction is of fundamental importance, and it will provide new insights into molecular electronics/plasmonics, single-entity electrochemistry, and nanooptoelectronics. Here, a facile method to form plasmonic molecular junctions is reported by utilizing single gold nanoparticle (NP) collision events at a highly curved gold nanoelectrode modified with a self-assembled monolayer. By using time-resolved electrochemical current measurement and surface-enhanced Raman scattering spectroscopy, the current changes and the evolution of interfacial chemical bonding are successfully observed in the newly formed molecular tunnel junctions during and after the gold NP "hit-n-stay" and "hit-n-run" collision events. The results lead to an in-depth understanding of the single NP motion and the associated molecular level changes during the formation of the plasmonic molecular junctions in a single NP collision event. This method also provides a new platform to study molecular changes at the single molecule level during electron transport in a dynamic molecular tunnel junction.
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Affiliation(s)
- Jing Guo
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Jie Pan
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Shuai Chang
- College of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Xuewen Wang
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Na Kong
- Center for Chemistry and Biotechnology, School of Life and Environmental Science, Deakin University, VIC, 3216, Australia
| | - Wenrong Yang
- Center for Chemistry and Biotechnology, School of Life and Environmental Science, Deakin University, VIC, 3216, Australia
| | - Jin He
- Department of Physics, Florida International University, Miami, FL, 33199, USA
- Department of Physics and Biomolecular Science Institute, Florida International University, Miami, FL, 33199, USA
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42
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Jiao X, Tanner EEL, Sokolov SV, Palgrave RG, Young NP, Compton RG. Understanding nanoparticle porosity via nanoimpacts and XPS: electro-oxidation of platinum nanoparticle aggregates. Phys Chem Chem Phys 2018; 19:13547-13552. [PMID: 28504288 DOI: 10.1039/c7cp01737e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The porosity of platinum nanoparticle aggregates (PtNPs) is investigated electrochemically via particle-electrode impacts and by XPS. The mean charge per oxidative transient is measured from nanoimpacts; XPS shows the formation of PtO and PtO2 in relative amounts defined by the electrode potential and an average oxidation state is deduced as a function of potential. The number of platinum atoms oxidised per PtNP is calculated and compared with two models: solid and porous spheres, within which there are two cases: full and surface oxidation. This allows insight into extent to which the internal surface of the aggregate is 'seen' by the solution and is electrochemically active.
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Affiliation(s)
- Xue Jiao
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
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43
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Sun T, Wang D, Mirkin M. Electrochemistry at a single nanoparticle: from bipolar regime to tunnelling. Faraday Discuss 2018; 210:173-188. [DOI: 10.1039/c8fd00041g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper is concerned with long-distance interactions between an unbiased metal nanoparticle (NP) and a nanoelectrode employed as a tip in the scanning electrochemical microscope (SECM).
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Affiliation(s)
- Tong Sun
- Department of Chemistry and Biochemistry
- Queens College-CUNY
- Flushing
- USA
- The Graduate Center of CUNY
| | - Dengchao Wang
- Department of Chemistry and Biochemistry
- Queens College-CUNY
- Flushing
- USA
| | - Michael V. Mirkin
- Department of Chemistry and Biochemistry
- Queens College-CUNY
- Flushing
- USA
- The Graduate Center of CUNY
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44
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Kai T, Zoski CG, Bard AJ. Scanning electrochemical microscopy at the nanometer level. Chem Commun (Camb) 2018; 54:1934-1947. [DOI: 10.1039/c7cc09777h] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chemical and electrochemical reactions at high temporal and spatial resolution can be studied using nanoscale SECM.
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Affiliation(s)
- Tianhan Kai
- Center for Electrochemistry
- Department of Chemistry
- The University of Texas at Austin
- Austin
- USA
| | - Cynthia G. Zoski
- Center for Electrochemistry
- Department of Chemistry
- The University of Texas at Austin
- Austin
- USA
| | - Allen J. Bard
- Center for Electrochemistry
- Department of Chemistry
- The University of Texas at Austin
- Austin
- USA
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45
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Gao R, Ying YL, Li YJ, Hu YX, Yu RJ, Lin Y, Long YT. A 30 nm Nanopore Electrode: Facile Fabrication and Direct Insights into the Intrinsic Feature of Single Nanoparticle Collisions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201710201] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rui Gao
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yi-Lun Ying
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yuan-Jie Li
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yong-Xu Hu
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Ru-Jia Yu
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yao Lin
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yi-Tao Long
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
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46
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Gao R, Ying YL, Li YJ, Hu YX, Yu RJ, Lin Y, Long YT. A 30 nm Nanopore Electrode: Facile Fabrication and Direct Insights into the Intrinsic Feature of Single Nanoparticle Collisions. Angew Chem Int Ed Engl 2017; 57:1011-1015. [DOI: 10.1002/anie.201710201] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/27/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Rui Gao
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yi-Lun Ying
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yuan-Jie Li
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yong-Xu Hu
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Ru-Jia Yu
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yao Lin
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
| | - Yi-Tao Long
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering; East China University of Science and Technology; Shanghai 200237 P.R. China
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47
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Morteza Najarian A, Chen R, Balla RJ, Amemiya S, McCreery RL. Ultraflat, Pristine, and Robust Carbon Electrode for Fast Electron-Transfer Kinetics. Anal Chem 2017; 89:13532-13540. [PMID: 29132207 DOI: 10.1021/acs.analchem.7b03903] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron-beam (e-beam) deposition of carbon on a gold substrate yields a very flat (0.43 nm of root-mean-square roughness), amorphous carbon film consisting of a mixture of sp2- and sp3-hybridized carbon with sufficient conductivity to avoid ohmic potential error. E-beam carbon (eC) has attractive properties for conventional electrochemistry, including low background current and sufficient transparency for optical spectroscopy. A layer of KCl deposited by e-beam to the eC surface without breaking vacuum protects the surface from the environment after fabrication until dissolved by an ultrapure electrolyte solution. Nanogap voltammetry using scanning electrochemical microscopy (SECM) permits measurement of heterogeneous standard electron-transfer rate constants (k°) in a clean environment without exposure of the electrode surface to ambient air. The ultraflat eC surface permitted nanogap voltammetry with very thin electrode-to-substrate gaps, thus increasing the diffusion limit for k° measurement to >14 cm/s for a gap of 44 nm. Ferrocene trimethylammonium as the redox mediator exhibited a diffusion-limited k° for the previously KCl-protected eC surface, while k° was 1.45 cm/s for unprotected eC. The k° for Ru(NH3)63+/2+ increased from 1.7 cm/s for unprotected eC to above the measurable limit of 6.9 cm/s for a KCl-protected eC electrode.
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Affiliation(s)
- Amin Morteza Najarian
- Department of Chemistry, University of Alberta , Edmonton, Alberta T6G 2R3, Canada.,National Institute for Nanotechnology, National Research Council Canada , Edmonton, Alberta T6G 2G2, Canada
| | - Ran Chen
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Ryan J Balla
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Richard L McCreery
- Department of Chemistry, University of Alberta , Edmonton, Alberta T6G 2R3, Canada.,National Institute for Nanotechnology, National Research Council Canada , Edmonton, Alberta T6G 2G2, Canada
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48
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Robinson DA, Liu Y, Edwards MA, Vitti NJ, Oja SM, Zhang B, White HS. Collision Dynamics during the Electrooxidation of Individual Silver Nanoparticles. J Am Chem Soc 2017; 139:16923-16931. [PMID: 29083174 DOI: 10.1021/jacs.7b09842] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent high-bandwidth recordings of the oxidation and dissolution of 35 nm radius Ag nanoparticles at a Au microelectrode show that these nanoparticles undergo multiple collisions with the electrode, generating multiple electrochemical current peaks. In the time interval between observed current peaks, the nanoparticles diffuse in the solution near the electrolyte/electrode interface. Here, we demonstrate that simulations of random nanoparticle motion, coupled with electrochemical kinetic parameters, quantitatively reproduce the experimentally observed multicurrent peak behavior. Simulations of particle diffusion are based on the nanoparticle-mass-based thermal nanoparticle velocity and the Einstein diffusion relations, while the electron-transfer rate is informed by the literature exchange current density for the Ag/Ag+ redox system. Simulations indicate that tens to thousands of particle-electrode collisions, each lasting ∼6 ns or less (currently unobservable on accessible experimental time scales), contribute to each experimentally observed current peak. The simulation provides a means to estimate the instantaneous current density during a collision (∼500-1000 A/cm2), from which we estimate a rate constant between ∼5 and 10 cm/s for the electron transfer between Ag nanoparticles and the Au electrode. This extracted rate constant is approximately equal to the thermal collisional velocity of the Ag nanoparticle (4.6 cm/s), the latter defining the theoretical upper limit of the electron-transfer rate constant. Our results suggest that only ∼1% of the surface atoms on the Ag nanoparticles are oxidized per instantaneous collision. The combined simulated and experimental results underscore the roles of Brownian motion and collision frequency in the interpretation of heterogeneous electron-transfer reactions involving nanoparticles.
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Affiliation(s)
- Donald A Robinson
- Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States
| | - Yuwen Liu
- Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.,College of Chemistry and Molecular Sciences, Wuhan University , Wuhan, 430072, China
| | - Martin A Edwards
- Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States
| | - Nicholas J Vitti
- Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States
| | - Stephen M Oja
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Bo Zhang
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - Henry S White
- Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States
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Anderson MJ, Ostojic N, Crooks RM. Microelectrochemical Flow Cell for Studying Electrocatalytic Reactions on Oxide-Coated Electrodes. Anal Chem 2017; 89:11027-11035. [DOI: 10.1021/acs.analchem.7b03016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Morgan J. Anderson
- Department of Chemistry and
Texas Materials Institute, The University of Texas at Austin, 105
East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Nevena Ostojic
- Department of Chemistry and
Texas Materials Institute, The University of Texas at Austin, 105
East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Richard M. Crooks
- Department of Chemistry and
Texas Materials Institute, The University of Texas at Austin, 105
East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
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50
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Chen R, Balla RJ, Lima A, Amemiya S. Characterization of Nanopipet-Supported ITIES Tips for Scanning Electrochemical Microscopy of Single Solid-State Nanopores. Anal Chem 2017; 89:9946-9952. [PMID: 28819966 PMCID: PMC5683184 DOI: 10.1021/acs.analchem.7b02269] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nanoscale scanning electrochemical microscopy (SECM) is a powerful scanning probe technique that enables high-resolution imaging of chemical processes at single nanometer-sized objects. However, it has been a challenging task to quantitatively understand nanoscale SECM images, which requires accurate characterization of the size and geometry of nanoelectrode tips. Herein, we address this challenge through transmission electron microscopy (TEM) of quartz nanopipets for SECM imaging of single solid-state nanopores by using nanopipet-supported interfaces between two immiscible electrolyte solutions (ITIES) as tips. We take advantage of the high resolution of TEM to demonstrate that laser-pulled quartz nanopipets reproducibly yield not only an extremely small tip diameter of ∼30 nm, but also a substantial tip roughness of ∼5 nm. The size and roughness of a nanopipet can be reliably determined by optimizing the intensity of the electron beam not to melt or deform the quartz nanotip without a metal coating. Electrochemically, the nanoscale ITIES supported by a rough nanotip gives higher amperometric responses to tetrabutylammonium than expected for a 30 nm diameter disc tip. The finite element simulation of sphere-cap ITIES tips accounts for the high current responses and also reveals that the SECM images of 100 nm diameter Si3N4 nanopores are enlarged along the direction of the tip scan. Nevertheless, spatial resolution is not significantly compromised by a sphere-cap tip, which can be scanned in closer proximity to the substrate. This finding augments the utility of a protruded tip, which can be fabricated and miniaturized more readily to facilitate nanoscale SECM imaging.
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Affiliation(s)
- Ran Chen
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Ryan J. Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Alex Lima
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo, SP, Brazil
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
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