1
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Lin Z, Saito H, Sato H, Sugimoto T. Positive and Negative Impacts of Interfacial Hydrogen Bonds on Photocatalytic Hydrogen Evolution. J Am Chem Soc 2024; 146:22276-22283. [PMID: 38968321 DOI: 10.1021/jacs.4c04271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2024]
Abstract
Understanding the behavior of water molecules at solid-liquid interfaces is crucial for various applications such as photocatalytic water splitting, a key technology for sustainable fuel production and chemical transformations. Despite extensive studies conducted in the past, the impact of the microscopic structure of interfacial water molecules on photocatalytic reactivity has not been directly examined. In this study, using real-time mass spectrometry and Fourier-transform infrared spectroscopy, we demonstrated the crucial role of hydrogen bond (H-bond) networks on the photocatalytic hydrogen evolution in thickness-controlled water adsorption layers on various TiO2 photocatalysts. Under controlled water vapor environments with relative humidity (RH) below 70%, we observed a monotonic increase in the H2 formation rate with increasing RH, indicating that reactive water molecules were present not only in the first adsorbed layer but also in several overlying layers. In contrast, at RH > 70%, when more than three water layers covered the catalyst surface, the H2 formation rate turned to decrease dramatically because of the structural rearrangement and hardening of the interfacial H-bond network induced during further water adsorption. This unique many-body effect of interfacial water was consistently observed for various TiO2 particles with different crystalline structures, including brookite, anatase, and a mixture of anatase and rutile. Our results demonstrated that depositing several water layers in a water vapor environment with RH ∼ 70% is optimal for photocatalytic hydrogen evolution rather than liquid-phase reaction conditions in aqueous solutions. This study provides molecular-level insights into designing interfacial water conditions to enhance photocatalytic performance.
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Affiliation(s)
- Zhongqiu Lin
- Department of Materials Molecular Science, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8585, Japan
| | - Hikaru Saito
- Department of Materials Molecular Science, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
| | - Hiromasa Sato
- Department of Materials Molecular Science, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
| | - Toshiki Sugimoto
- Department of Materials Molecular Science, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8585, Japan
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2
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He R, Luo KH. Mechanisms of microexplosion-accelerated pyrolysis and oxidation of lithium-containing droplets: an atomistic perspective. NANOSCALE 2024. [PMID: 39101367 DOI: 10.1039/d4nr00592a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Microexplosion has been extensively studied in the context of fuel spray and droplet evaporation in engines, while its existence, impact and atomistic insight have rarely been explored in the context of flame synthesis of nanoparticles. In this study, reactive force-field molecular dynamics simulations are performed to elucidate the mechanisms of pyrolysis and oxidation of an isolated lithium nitrate nanodroplet. During the pyrolysis process, the nucleation and growth of a bubble are observed inside the droplet, which should be ascribed to the release of nitrogen and oxygen gases from the decomposition of lithium nitrate, ultimately leading to rapid droplet fragmentation (microexplosion). To demonstrate the role of microexplosion with various intensities, via altering ambient temperature and addition of oxygen gas into the environment, thorough analyses of bond reactions, droplet morphology and compounds of the synthesized lithium nanoparticles are carried out. With elevated ambient temperature, the droplet substantially expands due to bubble growth and the time required for droplet disruption is shortened, which implies the enhanced strength of microexplosion. Simultaneously, the connection between the lithium and other atoms becomes weak, as evidenced by a decrease in the number of lithium bonds. These give rise to a reduction in the quantity of large-sized lithium agglomerates and simultaneously an increase in the amount of fine lithium nanoparticles. To further clarify the reaction mechanism for a lithium-containing droplet under various ambient conditions, three reaction modes, i.e., core-shell diffusion-controlled, microexplosion-accelerated and microexplosion-dominated, are distinguished based on the intensity of microexplosion and the quality of synthesized lithium nanoparticles. Fine lithium-containing nanoparticles are expected to be produced in the microexplosion-dominated mode under high temperature conditions.
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Affiliation(s)
- Ruitian He
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
| | - Kai H Luo
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
- Shanghai Institute for Advanced Study, Zhejiang University, Shanghai 201203, China
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3
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Li Z, Wang J, Yang C, Liu L, Yang JY. Thermal transport across TiO2-H2O interface involving water dissociation: Ab initio-assisted deep potential molecular dynamics. J Chem Phys 2023; 159:144701. [PMID: 37811827 DOI: 10.1063/5.0167238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/20/2023] [Indexed: 10/10/2023] Open
Abstract
Water dissociation on TiO2 surfaces has been known for decades and holds great potential in various applications, many of which require a proper understanding of thermal transport across the TiO2-H2O interface. Molecular dynamics (MD) simulations play an important role in characterizing complex systems' interfacial thermal transport properties. Nevertheless, due to the imprecision of empirical force field potentials, the interfacial thermal transport mechanism involving water dissociation remains to be determined. To cope with this, a deep potential (DP) model is formulated through the utilization of ab initio datasets. This model successfully simulates interfacial thermal transport accompanied by water dissociation on the TiO2 surfaces. The trained DP achieves a total energy accuracy of ∼238.8 meV and a force accuracy of ∼197.05 meV/Å. The DPMD simulations show that water dissociation induces the formation of hydrogen bonding networks and molecular bridges. Structural modifications further affect interfacial thermal transport. The interfacial thermal conductance estimated by DP is ∼8.54 × 109 W/m2 K, smaller than ∼13.17 × 109 W/m2 K by empirical potentials. The vibrational density of states (VDOS) quantifies the differences between the DP model and empirical potentials. Notably, the VDOS disparity between the adsorbed hydrogen atoms and normal hydrogen atoms demonstrates the influence of water dissociation on heat transfer processes. This work aims to understand the effect of water dissociation on thermal transport at the TiO2-H2O interface. The findings will provide valuable guidance for the thermal management of photocatalytic devices.
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Affiliation(s)
- Zhiqiang Li
- Optics & Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, China
| | - Jian Wang
- School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China
| | - Chao Yang
- School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China
| | - Linhua Liu
- Optics & Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, China
- School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China
| | - Jia-Yue Yang
- Optics & Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, China
- School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China
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4
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Amano KI, Furukawa S, Kubo Y, Nakamura Y, Ishii R, Tanase A, Maebayashi M, Hayashi T, Nishi N, Sakka T. Nonadditivities of the Particle Sizes Hidden in Model Pair Potentials and Their Effects on Physical Adsorptions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12999-13007. [PMID: 37658821 DOI: 10.1021/acs.langmuir.3c00968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
It is important to understand the mechanism of colloidal particle assembly near a substrate for development of drug delivery systems, micro-/nanorobots, batteries, heterogeneous catalysts, paints, and cosmetics. Understanding the mechanism is also important for crystallization of the colloidal particles and proteins. In this study, we calculated the physical adsorption of colloidal particles on a flat wall mainly using the integral equation theory, wherein small and large colloidal particles were employed. In the calculation system, like-charged electric double-layer potentials were used as pair potentials. In some cases, it was found that the small particles are more easily adsorbed. This result is unusual from the viewpoint of the Asakura-Oosawa theory, and we call it a "reversal phenomenon". Theoretical analysis revealed that the reversal phenomenon originates from the nonadditivities of the particle sizes. Using the knowledge obtained from this study, we invented a method to analyze the size nonadditivity hidden in model pair potentials. The method will be useful for confirmation of various simulation results regarding the adsorption and development of force fields for colloidal particles, proteins, and solutes.
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Affiliation(s)
- Ken-Ichi Amano
- Department of Applied Biological Chemistry, Faculty of Agriculture, Meijo University, Nagoya 468-8502, Japan
| | - Satoshi Furukawa
- Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Yuto Kubo
- Interdisciplinary Program of Biomedical Engineering, Assistive Technology, and Art and Sports Sciences, Faculty of Engineering, Niigata University, Niigata 950-2181, Japan
| | - Yuka Nakamura
- Interdisciplinary Program of Biomedical Engineering, Assistive Technology, and Art and Sports Sciences, Faculty of Engineering, Niigata University, Niigata 950-2181, Japan
| | - Rina Ishii
- Department of Applied Biological Chemistry, Faculty of Agriculture, Meijo University, Nagoya 468-8502, Japan
| | - Ayane Tanase
- Department of Applied Biological Chemistry, Faculty of Agriculture, Meijo University, Nagoya 468-8502, Japan
| | - Masahiro Maebayashi
- Department of Applied Biological Chemistry, Faculty of Agriculture, Meijo University, Nagoya 468-8502, Japan
| | - Tomohiko Hayashi
- Interdisciplinary Program of Biomedical Engineering, Assistive Technology, and Art and Sports Sciences, Faculty of Engineering, Niigata University, Niigata 950-2181, Japan
| | - Naoya Nishi
- Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Tetsuo Sakka
- Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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5
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Selmani A, Siboulet B, Špadina M, Foucaud Y, Dražić G, Radatović B, Korade K, Nemet I, Kovačević D, Dufrêche JF, Bohinc K. Cation Adsorption in TiO 2 Nanotubes: Implication for Water Decontamination. ACS APPLIED NANO MATERIALS 2023; 6:12711-12725. [PMID: 37533543 PMCID: PMC10391741 DOI: 10.1021/acsanm.3c00916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/13/2023] [Indexed: 08/04/2023]
Abstract
TiO2 nanotubes constitute very promising nanomaterials for water decontamination by the removal of cations. We combined a range of experimental techniques from structural analyses to measurements of the properties of aqueous suspensions of nanotubes, with (i) continuous solvent modeling and (ii) quantum DFT-based simulations to assess the adsorption of Cs+ on TiO2 nanotubes and to predict the separation of metal ions. The methodology is set to be operable under realistic conditions, which, in this case, include the presence of CO2 that needs to be treated as a substantial contaminant, both in experiments and in models. The mesoscopic model, based on the Poisson-Boltzmann equation and surface adsorption equilibrium, predicts that H+ ions are the charge-determining species, while Cs+ ions are in the diffuse layer of the outer surface with a significant contribution only at high concentrations and high pH. The effect of the size of nanotubes in terms of the polydispersity and the distribution of the inner and outer radii is shown to be a third-order effect that is very small when the nanotube layer is not very thick (ranging from 1 to 2 nm). Besides, DFT-based molecular dynamics simulations demonstrate that, for protonation, the one-site and successive association assumption is correct, while, for Cs+ adsorption, the size of the cation is important and the adsorption sites should be carefully defined.
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Affiliation(s)
- Atiđa Selmani
- Division
of Physical Chemistry, Ruđer Bošković
Institute, Bijenička
Cesta 54, 10000 Zagreb, Croatia
- Pharmaceutical
Technology & Biopharmacy, Institute
of Pharmaceutical Sciences, University of Graz, A-8010, Graz, Austria
| | - Bertrand Siboulet
- ICSM,
Université Montpellier, CEA, CNRS, ENSCM, 30207 Bagnols-sur-Ceze, France
| | - Mario Špadina
- Division
of Physical Chemistry, Ruđer Bošković
Institute, Bijenička
Cesta 54, 10000 Zagreb, Croatia
- Faculty
of Health Sciences, University of Ljubljana, Zdravstvena 5, SI-1000 Ljubljana, Slovenia
| | - Yann Foucaud
- ICSM,
Université Montpellier, CEA, CNRS, ENSCM, 30207 Bagnols-sur-Ceze, France
| | - Goran Dražić
- Laboratory
for Materials Chemistry, National Institute
of Chemistry, Hajdrihova ulica 19, SI-1000 Ljubljana, Slovenia
| | | | - Karla Korade
- Faculty of
Science, University of Zagreb, Horvatovac 102A, 10 000 Zagreb, Croatia
| | - Ivan Nemet
- Faculty of
Science, University of Zagreb, Horvatovac 102A, 10 000 Zagreb, Croatia
| | - Davor Kovačević
- Faculty of
Science, University of Zagreb, Horvatovac 102A, 10 000 Zagreb, Croatia
| | | | - Klemen Bohinc
- Faculty
of Health Sciences, University of Ljubljana, Zdravstvena 5, SI-1000 Ljubljana, Slovenia
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6
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Recio-Poo M, Morales-García Á, Illas F, Bromley ST. Crystal properties without crystallinity? Influence of surface hydroxylation on the structure and properties of small TiO 2 nanoparticles. NANOSCALE 2023; 15:4809-4820. [PMID: 36786054 DOI: 10.1039/d3nr00141e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Titania (TiO2) nanoparticles (NPs) are widely employed in applications that take advantage of their photochemical properties (e.g. pollutant degradation, photocatalysis). Here, we study the interrelation between crystallinity, surface hydroxylation and electronic structure in titania NPs with 1.4-2.3 nm diameters using all electron density functional theory-based calculations. We show how the distribution of local coordination environments of the atoms in thermally annealed quasi-spherical non-crystalline NPs converge to those in correspondingly sized faceted crystalline anatase NPs upon increasing hydroxylation. When highly hydroxylated, annealed NPs also possess electronic energy gaps with very similar energies and band edge orbital characters to those of the crystalline anatase NPs. We refer to the crystallite-mimicking non-crystalline annealed NPs as "crystalikes". Small stable crystalike NPs could allow for photochemical applications of titania in the size range where crystalline anatase NPs tend to become thermodynamically unfavoured (<3-5 nm). Our work implies the anatase crystal structure may not be as essential as previously assumed for TiO2 NP applications and generally suggests that crystalikes could be possible in other nanomaterials.
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Affiliation(s)
- Miguel Recio-Poo
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Ángel Morales-García
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Stefan T Bromley
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
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7
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Potential Use of Chitosan-TiO 2 Nanocomposites for the Electroanalytical Detection of Imidacloprid. Polymers (Basel) 2022; 14:polym14091686. [PMID: 35566856 PMCID: PMC9099656 DOI: 10.3390/polym14091686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/15/2022] [Accepted: 02/23/2022] [Indexed: 01/27/2023] Open
Abstract
The detection of toxic insecticides is a major scientific and technological challenge. In this regard, imidacloprid is a neonicotinoid that is a systemic insecticide that can accumulate in agricultural products and affect human health. This work aims to study the properties of chitosan–TiO2 nanocomposites in which nanoparticles with high surface area serve as molecular recognition sites for electroanalytical imidacloprid detection. We show that the best sensitivity to imidacloprid was obtained using a modified electrode with a chitosan–TiO2 nanocomposite with a 40 wt.% of TiO2 nanoparticles. By using a three-phase effective permittivity model which includes chitosan, TiO2, an interface layer between nanoparticles and a matrix, we showed that nanocomposites with 40 wt.% of TiO2 the interface volume fraction reaches a maximum. At higher nanoparticle concentration, the sensitivity of the sensor decreases due to the decreasing of the interface volume fraction, agglomeration of nanoparticles and a decrease in their effective surface area. The methodology presented can be helpful in the design and optimization of polymer-based nanocomposites for a variety of applications.
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8
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Realistic Modelling of Dynamics at Nanostructured Interfaces Relevant to Heterogeneous Catalysis. Catalysts 2022. [DOI: 10.3390/catal12010052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The focus of this short review is directed towards investigations of the dynamics of nanostructured metallic heterogeneous catalysts and the evolution of interfaces during reaction—namely, the metal–gas, metal–liquid, and metal–support interfaces. Indeed, it is of considerable interest to know how a metal catalyst surface responds to gas or liquid adsorption under reaction conditions, and how its structure and catalytic properties evolve as a function of its interaction with the support. This short review aims to offer the reader a birds-eye view of state-of-the-art methods that enable more realistic simulation of dynamical phenomena at nanostructured interfaces by exploiting resource-efficient methods and/or the development of computational hardware and software.
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9
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Kim G, Kim G, Kim D, Jung OS. Subtle metal( ii) effects of 2D coordination networks on SCSC guest exchange. CrystEngComm 2022. [DOI: 10.1039/d2ce00837h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The multi-channel crystals consisting of 2-D networks G@[M(NO3)2L] are an unusually efficient, tolerant, and reproducible matrix offering M-dependent adsorption/desorption of various guest molecules in the single-crystal-to-single-crystal mode.
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Affiliation(s)
- Gyeongwoo Kim
- Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea
| | - Gyeongmin Kim
- Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea
| | - Dongwon Kim
- Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea
| | - Ok-Sang Jung
- Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea
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10
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Shi X, Lin X, Luo R, Wu S, Li L, Zhao ZJ, Gong J. Dynamics of Heterogeneous Catalytic Processes at Operando Conditions. JACS AU 2021; 1:2100-2120. [PMID: 34977883 PMCID: PMC8715484 DOI: 10.1021/jacsau.1c00355] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 05/02/2023]
Abstract
The rational design of high-performance catalysts is hindered by the lack of knowledge of the structures of active sites and the reaction pathways under reaction conditions, which can be ideally addressed by an in situ/operando characterization. Besides the experimental insights, a theoretical investigation that simulates reaction conditions-so-called operando modeling-is necessary for a plausible understanding of a working catalyst system at the atomic scale. However, there is still a huge gap between the current widely used computational model and the concept of operando modeling, which should be achieved through multiscale computational modeling. This Perspective describes various modeling approaches and machine learning techniques that step toward operando modeling, followed by selected experimental examples that present an operando understanding in the thermo- and electrocatalytic processes. At last, the remaining challenges in this area are outlined.
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Affiliation(s)
- Xiangcheng Shi
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
- Joint
School of National University of Singapore and Tianjin University,
International Campus of Tianjin University, Fuzhou 350207, China
| | - Xiaoyun Lin
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Ran Luo
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Shican Wu
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Lulu Li
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Zhi-Jian Zhao
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Jinlong Gong
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
- Joint
School of National University of Singapore and Tianjin University,
International Campus of Tianjin University, Fuzhou 350207, China
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11
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Bischoff M, Biriukov D, Předota M, Marchioro A. Second Harmonic Scattering Reveals Ion-Specific Effects at the SiO 2 and TiO 2 Nanoparticle/Aqueous Interface. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:25261-25274. [PMID: 35591899 PMCID: PMC9109693 DOI: 10.1021/acs.jpcc.1c07191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/12/2021] [Indexed: 06/01/2023]
Abstract
Ion-specific effects play a crucial role in controlling the stability of colloidal systems and regulating interfacial processes. Although mechanistic pictures have been developed to explain the electrostatic structure of solid/water colloidal interfaces, ion-specific effects remain poorly understood. Here we quantify the average interfacial water orientation and the electrostatic surface potential around 100 nm SiO2 and TiO2 colloidal particles in the presence of NaCl, RbCl, and CaCl2 using polarimetric angle-resolved second harmonic scattering. We show that these two parameters can be used to establish the ion adsorption mechanism in a low ionic strength regime (<1 mM added salt). The relative differences between salts as a function of the ionic strength demonstrate cation- and surface-specific preferences for inner- vs outer-sphere adsorption. Compared to monovalent Rb+ and Na+, Ca2+ is found to be preferentially adsorbed as outer-sphere on SiO2 surfaces, while a dominant inner-sphere adsorption is observed for Ca2+ on TiO2. Molecular dynamics simulations performed on crystalline SiO2 and TiO2 surfaces support the experimental conclusions. This work contributes to the understanding of the electrostatic environment around colloidal nanoparticles on a molecular level by providing insight into ion-specific effects with micromolar sensitivity.
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Affiliation(s)
- Marie Bischoff
- Laboratory
for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI),
and Institute of Materials Science (IMX), School of Engineering (STI), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Denys Biriukov
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Department
of Physics, Faculty of Science, University
of South Bohemia, Branišovská 1760, 370
05 České Budějovice, Czech Republic
| | - Milan Předota
- Department
of Physics, Faculty of Science, University
of South Bohemia, Branišovská 1760, 370
05 České Budějovice, Czech Republic
| | - Arianna Marchioro
- Laboratory
for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI),
and Institute of Materials Science (IMX), School of Engineering (STI), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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12
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González D, Sodupe M, Rodríguez-Santiago L, Solans-Monfort X. Surface morphology controls water dissociation on hydrated IrO 2 nanoparticles. NANOSCALE 2021; 13:14480-14489. [PMID: 34473817 DOI: 10.1039/d1nr03592d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Iridium oxide is a highly efficient catalyst for the oxygen evolution reaction, whose large-scale application requires decreasing the metal content. This is achieved using small nanoparticles. The knowledge of the water-IrO2 nanoparticle interface is of high importance to understand the IrO2 behavior as electrocatalyst in aqueous solutions. In this contribution, DFT (PBE-D2) calculations and AIMD simulations on IrO2 nanoparticle models of different sizes ((IrO2)33 and (IrO2)115) are performed. Results show that two key factors determine the H2O adsorption energy and the preferred adsorption structure (molecular or dissociated water): metal coordination and hydrogen bonding with oxygen bridge atoms of the IrO2 surface. Regarding metal coordination, and since the tetragonal distortion existing in IrO2 is retained on the nanoparticle models, the adsorption at iridium axial vacant sites implies stronger Ir-H2O interactions, which favors water dissociation. In contrast, Ir-H2O interaction at equatorial vacant sites is weaker and thus the relative stability of molecular and dissociated forms becomes similar. Hydrogen bonding increases adsorption energy and favors water dissociation. Thus, tip and corner sites of the nanoparticle, with no oxygen bridge atoms nearby, exhibit the smallest adsorption energies and a preference for the molecular form. Overall, the presence of rather isolated tip and corner sites in the nanoparticle leads to lower adsorption energies and a smaller degree of water dissociation when compared with extended surfaces.
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Affiliation(s)
- Danilo González
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| | - Mariona Sodupe
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
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13
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Mino L, Morales-García Á, Bromley ST, Illas F. Understanding the nature and location of hydroxyl groups on hydrated titania nanoparticles. NANOSCALE 2021; 13:6577-6585. [PMID: 33885537 DOI: 10.1039/d1nr00610j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
TiO2 nanoparticles (NPs) are intensively studied and widely used due to their huge potential in numerous applications involving their interaction with ultraviolet light (e.g., photocatalysis and sunscreens). Typically, these NPs are in water-containing environments and thus tend to be hydrated. As such, there is a growing need to better understand the physicochemical properties of hydrated TiO2 NPs in order to improve their performance in photochemical applications (e.g., photocatalytic water splitting) and to minimise their environmental impact (e.g., potential biotoxicity). To help address the need for reliable and detailed data on how nano-titania interacts with water, we present a systematic experimental and theoretical study of surface hydroxyl (OH) groups on photoactive anatase TiO2 NPs. Employing well-defined experimentally synthesised NPs and detailed realistic NP models, we obtain the measured and computed infrared spectra of the surface hydroxyls, respectively. By comparing the experimental and theoretical spectra we are able to identify the type and location of different OH groups in these NP systems. Specifically, our study allows us to provide unprecedented and detailed information about the coverage-dependent distribution of hydroxyl groups on the surface of experimental titania NPs, the degree of their H-bonding interactions and their associated assigned vibrational modes. Our work promises to lead to new routes for developing new and safe nanotechnologies based on hydrated TiO2 NPs.
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Affiliation(s)
- Lorenzo Mino
- Department of Chemistry and NIS Centre, University of Torino, via Giuria 7, 10125 Torino, Italy.
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