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Jiang L, Cao W, Li Z, Wang C, Bi H. Interfacial Engineering of Fluorescent Carbon Dots with Metal Oxides for Real-Time Visualization of Oxygen Vacancy Dynamics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402827. [PMID: 39017030 DOI: 10.1002/smll.202402827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/03/2024] [Indexed: 07/18/2024]
Abstract
Oxygen vacancy (Vo), as one of the most common surface defects, significantly influence the physiochemical properties of metal oxides. However, it remains a challenge for existing techniques to visualize the evolution of Vo during redox process due to its heterogeneous distribution, small size, and dynamic nature. Herein, the real-time monitoring of such microscopic interfacial events is reported by advantage of the high-contrast fluorescence response of carbon dots (H-CDs) to Vo. The green emissive H-CDs possess a unique disc-shaped structure and exceptional hydrophilicity, allowing their tight adhesion to the surfaces of Vo-rich MgO by simple mixing. Subsequently, a water involved interfacial reaction occurred between H-CDs and Vo, resulting in gradual quenching of the original green emission and simultaneously emergence of bright red fluorescence. Moreover, the spatiotemporal diffusion dynamics and reaction kinetics are investigated by confocal laser scanning microscopy, revealing the time-dependent reorganization and structural heterogeneity at the interface. The finding provides a new toolbox for in situ imaging of Vo-triggered phenomena at a microscopic level, which will be helpful in promoting the rational design of oxide materials.
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Affiliation(s)
- Lei Jiang
- School of Chemistry and Chemical Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, China
| | - Wenjun Cao
- School of Materials Science and Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, China
| | - Zijian Li
- School of Materials Science and Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, China
| | - Chunchang Wang
- School of Materials Science and Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, China
| | - Hong Bi
- School of Materials Science and Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, China
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2
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Xue J, Fujitsuka M, Tachikawa T, Bao J, Majima T. Charge Trapping in Semiconductor Photocatalysts: A Time- and Space-Domain Perspective. J Am Chem Soc 2024; 146:8787-8799. [PMID: 38520348 DOI: 10.1021/jacs.3c14757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2024]
Abstract
Harnessing solar energy to produce value-added fuels and chemicals through photocatalysis techniques holds promise for establishing a sustainable and environmentally friendly energy economy. The intricate dynamics of photogenerated charge carriers lies at the core of the photocatalysis. The balance between charge trapping and band-edge recombination has a crucial influence on the activity of semiconductor photocatalysts. Consequently, the regulation of traps in photocatalysts becomes the key to optimizing their activities. Nevertheless, our comprehension of charge trapping, compared to that of well-studied charge recombination, remains somewhat limited. This limitation stems from the inherently heterogeneous nature of traps at both temporal and spatial scales, which renders the characterization of charge trapping a formidable challenge. Fortunately, recent advancements in both time-resolved spectroscopy and space-resolved microscopy have paved the way for considerable progress in the investigation and manipulation of charge trapping. In this Perspective, we focus on charge trapping in photocatalysts with the aim of establishing a direct link to their photocatalytic activities. To achieve this, we begin by elucidating the principles of advanced time-resolved spectroscopic techniques such as femtosecond time-resolved transient absorption spectroscopy and space-resolved microscopic methods, such as single-molecule fluorescence microscopy and surface photovoltage microscopy. Additionally, we provide an overview of noteworthy research endeavors dedicated to probing charge trapping using time- and space-resolved techniques. Our attention is then directed toward recent achievements in the manipulation of charge trapping in photocatalysts through defect engineering. Finally, we summarize this Perspective and discuss the future challenges and opportunities that lie ahead in the field.
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Affiliation(s)
- Jiawei Xue
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Mamoru Fujitsuka
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Takashi Tachikawa
- Department of Chemistry, Graduate School of Science and Molecular Photoscience Research Center, Kobe University, Kobe 657-8501, Japan
| | - Jun Bao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230029, China
- Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tetsuro Majima
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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3
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Wu T, King MR, Farag M, Pappu RV, Lew MD. Single fluorogen imaging reveals distinct environmental and structural features of biomolecular condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525727. [PMID: 36747818 PMCID: PMC9900924 DOI: 10.1101/2023.01.26.525727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Recent computations suggest that biomolecular condensates that form via macromolecular phase separation are network fluids featuring spatially inhomogeneous organization of the underlying molecules. Computations also point to unique conformations of molecules at condensate interfaces. Here, we test these predictions using high-resolution structural characterizations of condensates formed by intrinsically disordered prion-like low complexity domains (PLCDs). We leveraged the localization and orientational preferences of freely diffusing fluorogens and the solvatochromic effect whereby specific fluorogens are turned on in response to the physic-chemical properties of condensate microenvironments to facilitate single-molecule tracking and super-resolution imaging. We deployed three different fluorogens to probe internal microenvironments and molecular organization of PLCD condensates. The spatiotemporal resolution and environmental sensitivity afforded by single-fluorogen imaging shows that the internal environments of condensates are more hydrophobic than coexisting dilute phases. Molecules within condensates are organized in a spatially inhomogeneous manner featuring slow-moving nanoscale molecular clusters or hubs that coexist with fast-moving molecules. Finally, molecules at interfaces of condensates are found to have distinct orientational preferences when compared to the interiors. Our findings, which affirm computational predictions, help provide a structural basis for condensate viscoelasticity and dispel the notion of protein condensates being isotropic liquids defined by uniform internal densities.
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Affiliation(s)
- Tingting Wu
- Department of Electrical and Systems Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Matthew R King
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Mina Farag
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Rohit V Pappu
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
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4
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Shen M, Rackers WH, Sadtler B. Getting the Most Out of Fluorogenic Probes: Challenges and Opportunities in Using Single-Molecule Fluorescence to Image Electro- and Photocatalysis. CHEMICAL & BIOMEDICAL IMAGING 2023; 1:692-715. [PMID: 38037609 PMCID: PMC10685636 DOI: 10.1021/cbmi.3c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/04/2023] [Accepted: 10/07/2023] [Indexed: 12/02/2023]
Abstract
Single-molecule fluorescence microscopy enables the direct observation of individual reaction events at the surface of a catalyst. It has become a powerful tool to image in real time both intra- and interparticle heterogeneity among different nanoscale catalyst particles. Single-molecule fluorescence microscopy of heterogeneous catalysts relies on the detection of chemically activated fluorogenic probes that are converted from a nonfluorescent state into a highly fluorescent state through a reaction mediated at the catalyst surface. This review article describes challenges and opportunities in using such fluorogenic probes as proxies to develop structure-activity relationships in nanoscale electrocatalysts and photocatalysts. We compare single-molecule fluorescence microscopy to other microscopies for imaging catalysis in situ to highlight the distinct advantages and limitations of this technique. We describe correlative imaging between super-resolution activity maps obtained from multiple fluorogenic probes to understand the chemical origins behind spatial variations in activity that are frequently observed for nanoscale catalysts. Fluorogenic probes, originally developed for biological imaging, are introduced that can detect products such as carbon monoxide, nitrite, and ammonia, which are generated by electro- and photocatalysts for fuel production and environmental remediation. We conclude by describing how single-molecule imaging can provide mechanistic insights for a broader scope of catalytic systems, such as single-atom catalysts.
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Affiliation(s)
- Meikun Shen
- Department
of Chemistry and Biochemistry, University
of Oregon, Eugene, Oregon 97403, United States
| | - William H. Rackers
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Bryce Sadtler
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
- Institute
of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
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5
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Wen Z, Shi X, Li X, Liu W, Liu Y, Zhang R, Yu Y, Su J. Mesoporous TiO 2 Coatings Regulate ZnO Nanoparticle Loading and Zn 2+ Release on Titanium Dental Implants for Sustained Osteogenic and Antibacterial Activity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:15235-15249. [PMID: 36926829 DOI: 10.1021/acsami.3c00812] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two major issues are currently hindering the clinical practice of titanium dental implants for the lack of biological activities: immediate/early loading risks and peri-implantitis. To solve these issues, it is urgent to develop multifunctional implants modified with effective osteogenic and antibacterial properties. Zinc oxide nanoparticles (ZnO NPs) possess superior antibacterial activity; however, they can rapidly release Zn2+, causing cytotoxicity. In this study, a potential dental implant modification was creatively developed as ZnO nanoparticle-loaded mesoporous TiO2 coatings (nZnO/MTC-Ti) via the evaporation-induced self-assembly method (EISA) and one-step spin coating. The mesoporous TiO2 coatings (MTCs) regulated the synthesis and loading of ZnO NPs inside the nanosized pores. The synergistic effects of MTC and ZnO NPs on nZnO/MTC-Ti not only controlled the long-term steady-state release of Zn2+ but also optimized the charge distribution on the surface. Therefore, the cytotoxicity of ZnO NPs was resolved without triggering excessive reactive oxygen species (ROS). The increased extracellular Zn2+ further promoted a favorable intracellular zinc ion microenvironment through the modulation of zinc transporters (ZIP1 and ZnT1). Owing to that, the adhesion, proliferation, and osteogenic activity of bone mesenchymal stem cells (BMSCs) were improved. Additionally, nZnO/MTC-Ti inhibited the proliferation of oral pathogens (Pg and Aa) by inducing bacterial ROS production. For in vivo experiments, different implants were implanted into the alveolar fossa of Sprague-Dawley rats immediately after tooth extraction. The nZnO/MTC-Ti implants were found to possess a higher capability for enhancing bone regeneration, antibiosis, and osseointegration in vivo. These findings suggested the outstanding performance of nZnO/MTC-Ti implants in accelerating osseointegration and inhibiting bacterial infection, indicating a huge potential for solving immediate/early loading risks and peri-implantitis of dental implants.
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Affiliation(s)
- Zhuo Wen
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, P. R. China
| | - Xinyue Shi
- Institute of New Energy for Vehicles, Shanghai Key Laboratory for Development and Application of Metallic Functional Materials, School of Materials Science and Engineering, Tongji University, Shanghai 201804, P. R. China
| | - Xuejing Li
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, P. R. China
| | - Weicai Liu
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, P. R. China
| | - Yukun Liu
- Institute of New Energy for Vehicles, Shanghai Key Laboratory for Development and Application of Metallic Functional Materials, School of Materials Science and Engineering, Tongji University, Shanghai 201804, P. R. China
| | - Renyuan Zhang
- Institute of New Energy for Vehicles, Shanghai Key Laboratory for Development and Application of Metallic Functional Materials, School of Materials Science and Engineering, Tongji University, Shanghai 201804, P. R. China
| | - Yiqiang Yu
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, P. R. China
| | - Jiansheng Su
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, P. R. China
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6
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Anodic electrocatalytic behavior of graphite supported TiO2 towards the generation of hydroxyl radicals. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.141303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Xu Q, Li J, Gong X. Dual-emission carbon dots for sensitive fluorescence detection of metal ions and ethanol in water. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:3562-3572. [PMID: 36043438 DOI: 10.1039/d2ay01080a] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Carbon dots (CDs) have been widely used in biomedical fields because of their superior optical properties, high sensitivity and high selectivity to specific substances. However, there are few studies on trace detection of the ethanol content in aqueous solution using CDs. Herein, novel red fluorescent CDs with dual emission are synthesized and show good dispersibility in various solvents and excitation independence of photoluminescence (PL). After investigating the structure and properties of the red CDs, a multifunctional fluorescent nanoprobe based on the red CDs with high-sensitivity detection for dual-ion trace detection of Fe3+ and Cu2+ can be successfully constructed. The limit of detection of Fe3+ and Cu2+ can be up to 0.024 μM and 0.036 μM, respectively, which is superior to that in previous reports. Meanwhile, in view of the specific solvent effect on their PL, the red CDs are able to be applied for trace detection of the ethanol content in aqueous solution. The methods of colorimetry and fluorescence spectrometry are utilized to perform the threshold test and high-sensitivity quantitative analysis of the ethanol content in aqueous solution. Based on this, a multifunctional fluorescent nanoprobe based on the dual-emission red CDs can be obtained, which provides a promising way for their applications in detection and sensing fields.
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Affiliation(s)
- Qingqing Xu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, P. R. China.
| | - Jiurong Li
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, P. R. China.
| | - Xiao Gong
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, P. R. China.
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8
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Electronic state tuning over Mo-doped W18O49 ultrathin nanowires with enhanced molecular oxygen activation for desulfurization. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Yu D, Garcia A, Blum SA, Welsher KD. Growth Kinetics of Single Polymer Particles in Solution via Active-Feedback 3D Tracking. J Am Chem Soc 2022; 144:14698-14705. [PMID: 35867381 DOI: 10.1021/jacs.2c04990] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The ability to directly observe chemical reactions at the single-molecule and single-particle level has enabled the discovery of behaviors otherwise obscured by ensemble averaging in bulk measurements. However powerful, a common restriction of these studies to date has been the absolute requirement to surface tether or otherwise immobilize the chemical reagent/reaction of interest. This constraint arose from a fundamental limitation of conventional microscopy techniques, which could not track molecules or particles rapidly diffusing in three dimensions, as occurs in solution. However, many chemical processes occur entirely in the solution phase, leaving single-particle/-molecule analysis of this critical area of science beyond the scope of available technology. Here, we report the first kinetics studies of freely diffusing and actively growing single polymer-particles at the single-particle level freely diffusing in solution. Active-feedback single-particle tracking was used to capture three-dimensional (3D) trajectories and real-time volumetric images of freely diffusing polymer particles (D ≈ 10-12 m2/s) and extract the growth rates of individual particles in the solution phase. The observed growth rates show that the average growth rate is a poor representation of the true underlying variability in polymer-particle growth behavior. These data revealed statistically significant populations of faster- and slower-growing particles at different depths in the sample, showing emergent heterogeneity while particles are still freely diffusing in solution. These results go against the prevailing premise that chemical processes in freely diffusing solution will exhibit uniform kinetics. We anticipate that these studies will launch new directions of solution-phase, nonensemble-averaged measurements of chemical processes.
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Affiliation(s)
- Donggeng Yu
- Department of Chemistry, Duke University; Durham, North Carolina 27708, United States
| | - Antonio Garcia
- Department of Chemistry, University of California, Irvine; Irvine, California 92697, United States
| | - Suzanne A Blum
- Department of Chemistry, University of California, Irvine; Irvine, California 92697, United States
| | - Kevin D Welsher
- Department of Chemistry, Duke University; Durham, North Carolina 27708, United States
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10
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Cheng C, Fang Q, Fernandez-Alberti S, Long R. Depleted Oxygen Defect State Enhancing Tungsten Trioxide Photocatalysis: A Quantum Dynamics Perspective. J Phys Chem Lett 2022; 13:5571-5580. [PMID: 35696649 DOI: 10.1021/acs.jpclett.2c01541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Oxygen vacancies generally create midgap states in transition metal oxides, which are expected to decrease the photoelectrochemical water-splitting efficiency. Recent experiments defy this expectation but leave the mechanism unclear. Focusing on the photoanode WO3 as a prototypical system, we demonstrate using nonadiabatic molecular dynamics that an oxygen vacancy suppresses nonradiative electron-hole recombination, because the defect acts as an electron reservoir instead of a recombination center. The occupied midgap electrons prefer to be populated a priori compared to the band edge transition because of a larger transition dipole moment, converting to depleted/unoccupied trap states that rapidly accept conduction band electrons and then cause trap-assisted recombination by impeding the bandgap recombination regardless of oxygen vacancy configurations. The reported results provide a fundamental understanding of the "realistic" role of the oxygen vacancies and their influence on charge-phonon dynamics and carrier lifetime. The study generates valuable insights into the design of high-performance transition metal oxide photocatalysts.
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Affiliation(s)
- Cheng Cheng
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, China
| | - Qiu Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, China
| | - S Fernandez-Alberti
- Departamento de Cienciay Tecnologia, Universidad Nacional de Quilmes/CONICET, B1876BXD Bernal, Argentina
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, China
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11
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Shen M, Ding T, Tan C, Rackers WH, Zhang D, Lew MD, Sadtler B. In Situ Imaging of Catalytic Reactions on Tungsten Oxide Nanowires Connects Surface-Ligand Redox Chemistry with Photocatalytic Activity. NANO LETTERS 2022; 22:4694-4701. [PMID: 35674669 DOI: 10.1021/acs.nanolett.2c00674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Semiconductor nanocrystals are promising candidates for generating chemical feedstocks through photocatalysis. Understanding the role of ligands used to prepare colloidal nanocrystals in catalysis is challenging due to the complexity and heterogeneity of nanocrystal surfaces. We use in situ single-molecule fluorescence imaging to map the spatial distribution of active regions along individual tungsten oxide nanowires before and after functionalizing them with ascorbic acid. Rather than blocking active sites, we observed a significant enhancement in activity for photocatalytic water oxidation after treatment with ascorbic acid. While the initial nanowires contain inactive regions dispersed along their length, the functionalized nanowires show high uniformity in their photocatalytic activity. Spatial colocalization of the active regions with their surface chemical properties shows that oxidation of ascorbic acid during photocatalysis generates new oxygen vacancies along the nanowire surface. We demonstrate that controlling surface-ligand redox chemistry during photocatalysis can enhance the active site concentration on nanocrystal catalysts.
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Affiliation(s)
- Meikun Shen
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Che Tan
- Department of Energy, Environmental, and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - William H Rackers
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Dongyan Zhang
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Bryce Sadtler
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130, United States
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12
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Pei CY, Li T, Zhang M, Wang JW, Chang L, Xiong X, Chen W, Huang GB, Han DM. Synergistic effects of interface coupling and defect sites in WO3/InVO4 architectures for highly efficient nitrogen photofixation. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120875] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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13
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Zhang M, Yang C, Zhang Z, Tian W, Hui B, Zhang J, Zhang K. Tungsten oxide polymorphs and their multifunctional applications. Adv Colloid Interface Sci 2022; 300:102596. [PMID: 34990910 DOI: 10.1016/j.cis.2021.102596] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/04/2021] [Accepted: 12/25/2021] [Indexed: 12/12/2022]
Abstract
Owing to the natural abundance, easy availability, high stability, non-stoichiometry, and chemical diversity, considerable interest has been devoted to tungsten oxide (WO3-x) nanomaterials, and many advances have been achieved ranging from traditional catalysts and electronics to emerging artificial intelligence. This review focuses on recent progress of WO3-x polymorphs and their multifunctional applications. The structural diversity and crystal phase transitions of WO3-x and recent advances on the general synthesis of various WO3-x nanostructures are first summarized, since the crystal structure and morphology adjustment obviously affect the physiochemical merits of WO3-x materials. Then, their applications and related mechanisms in different fields are demonstrated, such as gas sensing, chromogenic (electro-, photo-, gaso-, and thermochromic), photocatalytic (pollutant degradation and water splitting), and emerging applications (biomedical, antibiotic, and artificial intelligence). With the advances highlighted here and the ongoing research efforts, the continuous breakthrough in functionalized WO3-x nanostructure and their attractive applications is foreseeable in the future.
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Affiliation(s)
- Mingxin Zhang
- State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Chao Yang
- State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Ziqi Zhang
- State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Weiliang Tian
- Key Laboratory of Chemical Engineering in South Xinjiang, College of Life Science, Tarim University, Alar 843300, PR China
| | - Bin Hui
- State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Jianxiao Zhang
- College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, PR China
| | - Kewei Zhang
- State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China.
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14
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15
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Tao X, Zheng K, Huang L. Plasma induced liquid-phase synthesis of Ce/Mo metal oxides as photocatalysts. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138903] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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16
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Zhang S, Zhang L, Fang S, Zhou J, Fan J, Lv K. Plasmonic semiconductor photocatalyst: Non-stoichiometric tungsten oxide. ENVIRONMENTAL RESEARCH 2021; 199:111259. [PMID: 33974839 DOI: 10.1016/j.envres.2021.111259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/10/2021] [Accepted: 04/25/2021] [Indexed: 06/12/2023]
Abstract
Semiconductor photocatalysis has attracted increasing attention due to its potential application in solving the problems related to energy crisis and environmental pollution. As a typical plasmonic semiconductor, non-stoichiometric tungsten oxide (WO3-X) has invoked significant interest for its unique property and excellent photocatalytic performance. In this review, we briefly introduce the fundamental properties of the WO3-x, and then summarize the synthesis methods such as solvothermal reaction, solid phase reduction and exfoliation treatment, together with the modification strategies such as doping and constructing homo-/hetero-junctions. Additionally, we emphasize the practical applications of WO3-x in hydrogen evolution, nitrogen fixation, carbon dioxide reduction, and pollutant degradation. Finally, comprehensive conclusions and perspectives on the fabrication of WO3-x photocatalyst leading to satisfactory performance are given as well.
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Affiliation(s)
- Sushu Zhang
- Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, PR China
| | - Li Zhang
- Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, PR China
| | - Shun Fang
- Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, PR China
| | - Jie Zhou
- Department of Urology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, 430061, China; Hubei Province Academy of Traditional Chinese Medicine, Wuhan, 430074, China.
| | - Jiajie Fan
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Kangle Lv
- Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, PR China.
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17
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Shen M, Ding T, Rackers WH, Tan C, Mahmood K, Lew MD, Sadtler B. Single-Molecule Colocalization of Redox Reactions on Semiconductor Photocatalysts Connects Surface Heterogeneity and Charge-Carrier Separation in Bismuth Oxybromide. J Am Chem Soc 2021; 143:11393-11403. [PMID: 34284584 DOI: 10.1021/jacs.1c02377] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The surface structure of semiconductor photocatalysts controls the efficiency of charge-carrier extraction during photocatalytic reactions. However, understanding the connection between surface heterogeneity and the locations where photogenerated charge carriers are preferentially extracted is challenging. Herein we use single-molecule fluorescence imaging to map the spatial distribution of active regions and quantify the activity for both photocatalytic oxidation and reduction reactions on individual bismuth oxybromide (BiOBr) nanoplates. Through a coordinate-based colocalization analysis, we quantify the spatial correlation between the locations where fluorogenic probe molecules are oxidized and reduced on the surface of individual nanoplates. Surprisingly, we observed two distinct photochemical behaviors for BiOBr particles prepared within the same batch, which exhibit either predominantly uncorrelated activity where electrons and holes are extracted from different sites or colocalized activity in which oxidation and reduction take place within the same nanoscale regions. By analyzing the emissive properties of the fluorogenic probes, we propose that electrons and holes colocalize at defect-deficient regions, while defects promote the selective extraction of one carrier type by trapping either electrons or holes. Although previous work has used defect engineering to enhance the activity of bismuth oxyhalides and other semiconductor photocatalysts for useful reductive half-reactions (e.g., CO2 or N2 reduction), our results show that defect-free regions are needed to promote both oxidation and reduction in fuel-generating photocatalysts that do not rely on sacrificial reagents.
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Affiliation(s)
- Meikun Shen
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - William H Rackers
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Che Tan
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Khalid Mahmood
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States.,Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Bryce Sadtler
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States.,Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
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18
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Establishment of live-cell-based coupled assay system for identification of compounds to modulate metabolic activities of cells. Cell Rep 2021; 36:109311. [PMID: 34233188 DOI: 10.1016/j.celrep.2021.109311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 03/29/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022] Open
Abstract
In this study, we present a live-cell-based fluorometric coupled assay system to identify the compounds that can regulate the targeted metabolic pathways in live cells. The assay is established through targeting specific metabolic pathways and using "input" and "output" metabolite pairs. The changes in the extracellular output that are generated and released into the extracellular media from the input are assessed as the activity of the pathway. The screening for the glycolytic pathway and amino acid metabolism reveals the activities of the present drugs, 6-BIO and regorafenib, that regulate the metabolic fate of tumor cells.
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19
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Rao F, Zhu G, Zhang W, Xu Y, Cao B, Shi X, Gao J, Huang Y, Huang Y, Hojamberdiev M. Maximizing the Formation of Reactive Oxygen Species for Deep Oxidation of NO via Manipulating the Oxygen-Vacancy Defect Position on (BiO)2CO3. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01251] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Fei Rao
- School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710119, P.R. China
| | - Gangqiang Zhu
- School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710119, P.R. China
| | - Weibin Zhang
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, P.R. China
| | - Yunhua Xu
- School of Chemistry and Chemical Engineering, Yulin University, Yulin 719000, P.R. China
| | - Baowei Cao
- School of Chemistry and Chemical Engineering, Yulin University, Yulin 719000, P.R. China
| | - Xianjin Shi
- State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, P.R. China
| | - Jianzhi Gao
- School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710119, P.R. China
| | - Yuhong Huang
- School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710119, P.R. China
| | - Yu Huang
- State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, P.R. China
| | - Mirabbos Hojamberdiev
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, Berlin 10623, Germany
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20
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Dong B, Mansour N, Huang TX, Huang W, Fang N. Single molecule fluorescence imaging of nanoconfinement in porous materials. Chem Soc Rev 2021; 50:6483-6506. [PMID: 34100033 DOI: 10.1039/d0cs01568g] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review covers recent progress in using single molecule fluorescence microscopy imaging to understand the nanoconfinement in porous materials. The single molecule approach unveils the static and dynamic heterogeneities from seemingly equal molecules by removing the ensemble averaging effect. Physicochemical processes including mass transport, surface adsorption/desorption, and chemical conversions within the confined space inside porous materials have been studied at nanometer spatial resolution, at the single nanopore level, with millisecond temporal resolution, and under real chemical reaction conditions. Understanding these physicochemical processes provides the ability to quantitatively measure the inhomogeneities of nanoconfinement effects from the confining properties, including morphologies, spatial arrangement, and trapping domains. Prospects and limitations of current single molecule imaging studies on nanoconfinement are also discussed.
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Affiliation(s)
- Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, USA.
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21
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Affiliation(s)
- Yi Xiao
- State Key Laboratory of Electroanalytical Chemistry and Jilin Province Key Laboratory of Low Carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences 5625 Renmin Street, Changchun Jilin 130022 China
- University of Science and Technology of China Hefei Anhui 230026 China
| | - Weilin Xu
- State Key Laboratory of Electroanalytical Chemistry and Jilin Province Key Laboratory of Low Carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences 5625 Renmin Street, Changchun Jilin 130022 China
- University of Science and Technology of China Hefei Anhui 230026 China
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22
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An J, Song X, Wan W, Chen Y, Si H, Duan H, Li L, Tang B. Kinetics of the Photoelectron-Transfer Process Characterized by Real-Time Single-Molecule Fluorescence Imaging on Individual Photocatalyst Particles. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00983] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Jinghua An
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Xiaoting Song
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Wenbo Wan
- School of Information Science and Engineering, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Yanzheng Chen
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Haibin Si
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Huichuan Duan
- School of Information Science and Engineering, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Lu Li
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in University of Shandong, Institute of Molecular and Nano Science, Shandong Normal University, Jinan 250014, People’s Republic of China
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23
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Peng W, Athukorale S, Hu J, Cui X, Zhang D. Kinetic spectroscopic quantification using two-step chromogenic and fluorogenic reactions: From theoretical modeling to experimental quantification of biomarkers in practical samples. Anal Chim Acta 2021; 1153:338293. [PMID: 33714449 DOI: 10.1016/j.aca.2021.338293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/20/2021] [Accepted: 02/01/2021] [Indexed: 11/27/2022]
Abstract
Kinetic chromogenic (CG) and fluorogenic (FG) quantification deduces analyte concentration based on the reaction rate between the CG/FG probe and its targeted molecule. Little progress has been made in the past half century in either the theory or the applications of the kinetic spectroscopic quantification methods. Current kinetic CG/FG quantification is limited only to a subset of CG/FG reactions that can be approximated as the single-step process, and more problematically, to research samples with no matrix interferences. Reported herein is a kinetic quantification model established for multistep CG/FG reactions and a proof-of-concept demonstration of direct kinetic FG quantification of biomarkers in practical samples. The kinetic spectral intensity of the CG/FG reactions with two rate-limiting steps comprises three temporal regions: an accelerating period where rate of signal change is increasingly rapid, a linear region where the rate of signal change is approximately constant, and a deceleration region where the rate of signal increase becomes progressively small. Kinetic quantification is performed through simple linear-curve-fitting of the kinetic signal in its linear time-course region. The theoretical model is validated with the dual CG/FG 2-thiobarbituric acid (TBA) and malondialdehyde (MDA) reaction. Proof-of-concept kinetic spectroscopic quantification of analytes in practical samples is demonstrated with the FG quantification of MDA in canned chicken. The only sample preparation is bench-top centrifugation followed by two sequential syringe filtrations. The total kinetic FG assay time is less than 10 min, more than 10 times more efficient than the current equilibrium-based MDA assay. The theoretical model and the measurement design strategies offered by this work should help transform the current kinetic spectroscopic quantification from a niche research tool to an indispensable technique for time-sensitive applications.
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Affiliation(s)
- Weiyu Peng
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, United States
| | - Sumudu Athukorale
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, United States
| | - Juan Hu
- Department of Mathematical Sciences, DePaul University, Chicago, IL, 60604, United States
| | - Xin Cui
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, United States.
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24
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Garcia A, Saluga SJ, Dibble DJ, López PA, Saito N, Blum SA. Does Selectivity of Molecular Catalysts Change with Time? Polymerization Imaged by Single‐Molecule Spectroscopy. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202010101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Antonio Garcia
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Shannon J. Saluga
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - David J. Dibble
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Pía A. López
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Nozomi Saito
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Suzanne A. Blum
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
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25
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Garcia A, Saluga SJ, Dibble DJ, López PA, Saito N, Blum SA. Does Selectivity of Molecular Catalysts Change with Time? Polymerization Imaged by Single‐Molecule Spectroscopy. Angew Chem Int Ed Engl 2020; 60:1550-1555. [DOI: 10.1002/anie.202010101] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/03/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Antonio Garcia
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Shannon J. Saluga
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - David J. Dibble
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Pía A. López
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Nozomi Saito
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
| | - Suzanne A. Blum
- Department of Chemistry University of California, Irvine Irvine CA 92697-2025 USA
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26
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Hou JT, Zhang M, Liu Y, Ma X, Duan R, Cao X, Yuan F, Liao YX, Wang S, Xiu Ren W. Fluorescent detectors for hydroxyl radical and their applications in bioimaging: A review. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213457] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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27
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Shen M, Ding T, Luo J, Tan C, Mahmood K, Wang Z, Zhang D, Mishra R, Lew MD, Sadtler B. Competing Activation and Deactivation Mechanisms in Photodoped Bismuth Oxybromide Nanoplates Probed by Single-Molecule Fluorescence Imaging. J Phys Chem Lett 2020; 11:5219-5227. [PMID: 32516535 DOI: 10.1021/acs.jpclett.0c01237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Oxygen vacancies in semiconductor photocatalysts play several competing roles, serving to both enhance light absorption and charge separation of photoexcited carriers as well as act as recombination centers for their deactivation. In this Letter, we show that single-molecule fluorescence imaging of a chemically activated fluorogenic probe can be used to monitor changes in the photocatalytic activity of bismuth oxybromide (BiOBr) nanoplates in situ during the light-induced formation of oxygen vacancies. We observe that the specific activities of individual nanoplates for the photocatalytic reduction of resazurin first increase and then progressively decrease under continuous laser irradiation. Ensemble structural characterization, supported by electronic-structure calculations, shows that irradiation increases the concentration of surface oxygen vacancies in the nanoplates, reduces Bi ions, and creates donor defect levels within the band gap of the semiconductor particles. These combined changes first enhance photocatalytic activity by increasing light absorption at visible wavelengths. However, high concentrations of oxygen vacancies lower the photocatalytic activity both by introducing new relaxation pathways that promote charge recombination before photoexcited electrons can be extracted and by weakening binding of resazurin to the surface of the nanoplates.
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Affiliation(s)
- Meikun Shen
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Jiang Luo
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Che Tan
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Khalid Mahmood
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Zheyu Wang
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Dongyan Zhang
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Rohan Mishra
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
- Department of Mechanical Engineering & Materials Science, Washington University, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Bryce Sadtler
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
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