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Ning X, Zhan L, Zhou X, Luo J, Wang Y. In-situ Bi-modified Pt towards glycerol and formic acid electro-oxidation: Effects of catalyst structure and surface microenvironment on activity and selectivity. J Colloid Interface Sci 2024; 655:920-930. [PMID: 37979297 DOI: 10.1016/j.jcis.2023.11.075] [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: 06/19/2023] [Revised: 11/06/2023] [Accepted: 11/11/2023] [Indexed: 11/20/2023]
Abstract
The performances of glycerol electro-oxidation reaction (GOR) and formic acid electro-oxidation reaction (FAOR) catalyzed by Pt catalyst were dramatically improved by adding Bi3+ into the reaction solution. The dynamic structure and microenvironment of in-situ Bi-modified Pt and their impact on the catalytic performances were revealed. A strong correlation was established between the Bi coverage of Pt-based catalysts and their resistance to CO poisoning and performance in GOR and FAOR. When Bi3+ increased to a certain amount, a Bi-shell containing hydroxides was formed on Pt surfaces except the formation of Pt-Bi ensemble. On Pt catalyst covered with 43.9 % Bi, the peak mass-specific activities of GOR and FAOR in forward scans were 4.2 and 34.7 times that of Pt/NCNTs, respectively. The peak electrochemical active surface area (ECSA)-specific activity of FAOR in forward scan for Pt with 52.6 % Bi coverage was 80.6 times that of Pt/NCNTs. The dehydrogenation process in FAOR and the 4-electron pathway in GOR were improved for Bi-modified Pt. The experimental results and DFT calculations indicated that the positively charged Bi and structure of Pt-Bi ensemble improved the adsorption and interaction of negatively charged intermediates, and the enhanced hydroxides facilitated the oxidation and removal of toxic intermediates, such as CO.
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Affiliation(s)
- Xiaomei Ning
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Material Chemistry in Guangdong General University, Lingnan Normal University, Zhanjiang 524048, China
| | - Liang Zhan
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Material Chemistry in Guangdong General University, Lingnan Normal University, Zhanjiang 524048, China.
| | - Xiaosong Zhou
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Material Chemistry in Guangdong General University, Lingnan Normal University, Zhanjiang 524048, China
| | - Jin Luo
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Material Chemistry in Guangdong General University, Lingnan Normal University, Zhanjiang 524048, China
| | - Yanli Wang
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Material Chemistry in Guangdong General University, Lingnan Normal University, Zhanjiang 524048, China
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2
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Lin M, Zhou Y, Bu L, Bai C, Tariq M, Wang H, Han J, Huang X, Zhou X. Single-Nanoparticle Coulometry Method with High Sensitivity and High Throughput to Study the Electrochemical Activity and Oscillation of Single Nanocatalysts. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007302. [PMID: 33719172 DOI: 10.1002/smll.202007302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/16/2021] [Indexed: 06/12/2023]
Abstract
To explore nanocatalysts with high electro-catalytic performance and less loading of precious metals, efforts have been made to develop electrochemical methods with high spatial resolution at the single nanoparticle level. Herein, a highly sensitive single-nanoparticle coulometry method is successfully developed to study the electrochemical activity and oscillation of single PtTe nanocatalysts. Based on microbattery reactions involving the formic acid electro-oxidation and the deposition of Ag on the single PtTe nanocatalyst surface, this method enables the transition from the undetectable sub-fA electric signal of the formic acid electro-oxidation into strong localized surface plasmon resonance scattering signal of Ag detected by dark-field microscopy. The lowest limiting current for a single nanocatalyst is found to be as low as 25.8 aA. Different trends of activity versus the formic acid concentration and types of activity of the single nanocatalyst have been discovered. Unveiled frequency-amplitude graph shows that the two electrochemical oscillation modes of low frequency with high amplitude and vice versa coexist in a single PtTe nanocatalyst, indicating the abundantly smooth surfaces and defects of nanocatalysts. This conducted study will open up the new avenue for further behavioral and mechanistic investigation of more types of nanocatalysts in the electrochemistry community.
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Affiliation(s)
- Mohan Lin
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Suzhou, 215123, China
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Yingke Zhou
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
- School of Materials Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Lingzheng Bu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Chuang Bai
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Suzhou, 215123, China
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Muhammad Tariq
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Huihui Wang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Suzhou, 215123, China
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Jinli Han
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiaoqing Huang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Xiaochun Zhou
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Suzhou, 215123, China
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123, China
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3
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Active electrochemical interfaces stabilized through self-organized potential oscillations. Electrochem commun 2020. [DOI: 10.1016/j.elecom.2020.106853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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4
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Nogueira JA, Krischer K, Varela H. Coupled Dynamics of Anode and Cathode in Proton‐Exchange Membrane Fuel Cells. Chemphyschem 2019; 20:3081-3088. [DOI: 10.1002/cphc.201900531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/18/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Jéssica A. Nogueira
- Institute of Chemistry of São CarlosUniversity of São Paulo P.O. Box 780 13560-970 São Carlos, SP Brazil
| | - Katharina Krischer
- Department of PhysicsTechnical University of Munich James-Franck-Str. 1 D-85748 Garching Germany
| | - Hamilton Varela
- Institute of Chemistry of São CarlosUniversity of São Paulo P.O. Box 780 13560-970 São Carlos, SP Brazil
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5
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Yoo JK, Rhee CK. Formic acid oxidation on Bi-modified Pt surfaces: Pt deposits on Au versus bulk Pt. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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6
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López-Sauri DA, Veleva L, Pérez-Ángel G. Potentiostatic current and galvanostatic potential oscillations during electrodeposition of cadmium. Phys Chem Chem Phys 2015; 17:22266-71. [PMID: 26243301 DOI: 10.1039/c5cp03253a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cathodic current and potential oscillations were observed during electrodeposition of cadmium from a cyanide electrolyte on a vertical platinum electrode, in potentiostatic and galvanostatic experiments. Electrochemical impedance spectroscopy experiments revealed a region of negative real impedance in a range of non-zero frequencies, in the second descending branch with a positive slope of the N-shape current-potential curve. This kind of dynamical behaviour is characteristic of the HN-NDR oscillators (oscillators with the N-Shape current-potential curve and hidden negative differential resistance). The oscillations could be mainly attributed to the changes in the real active cathodic area, due to the adsorption of hydrogen molecules and their detachment from the surface. The instabilities of the electrochemical processes were characterized by time series, Fast Fourier Transforms and 2-D phase portraits showing quasi-periodic oscillations.
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Affiliation(s)
- D A López-Sauri
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados (CINVESTAV-IPN), Carrt. Ant. A Progreso km. 6, CORDEMEX, 97310, Mérida, Yucatán, Mexico.
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Perini N, Batista BC, Angelo ACD, Epstein IR, Varela H. Long-Lasting Oscillations in the Electro-Oxidation of Formic Acid on PtSn Intermetallic Surfaces. Chemphyschem 2014; 15:1753-60. [DOI: 10.1002/cphc.201301186] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Indexed: 11/12/2022]
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8
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Baltrusaitis J, Hu YS, McFarland EW, Hellman A. Photoelectrochemical hydrogen production on α-Fe2O3 (0001): insights from theory and experiments. CHEMSUSCHEM 2014; 7:162-171. [PMID: 24130006 DOI: 10.1002/cssc.201300715] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/29/2013] [Indexed: 06/02/2023]
Abstract
The photoelectrochemical (PEC) decomposition of organic compounds in wastewater is investigated by using quantum chemical (DFT) methods to evaluate alternatives to water splitting for the production of renewable and sustainable hydrogen. Methanol is used as a model organic species for the theoretical evaluations of electrolysis on the surface of the widely available semiconductor hematite, α-Fe2 O3 , a widely studied photocatalyst. Three different α-Fe2 O3 surface terminations were investigated, including the predominant surface found in aqueous electrolytes, (OH)3 R. The PEC oxidation of methanol is energetically downhill, producing CO2 and protons. The protons are reduced to hydrogen on the cathode. Experimental PEC measurements were also performed for several polyalcoholic compounds, glycerol, erythritol, and xylitol, on α-Fe2 O3 as the photocatalyst and showed high incident-photon-to-current-efficiencies (IPCE) that were much greater than those of water splitting. Interestingly, high IPCEs were observed for hydrogen production from polyalcohols in the absence of any applied bias, which was not thought to be possible on hematite. These results support the potential application of PEC for hydrogen production by using widely available hematite for the PEC oxidation of selected components of organic wastewater present in large quantities from anthropogenic and industrial sources.
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Affiliation(s)
- Jonas Baltrusaitis
- PhotoCatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 53-489-3968; Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242 (USA).
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9
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Perini N, Sitta E, Angelo AC, Varela H. Electrocatalytic activity under oscillatory regime: The electro-oxidation of formic acid on ordered Pt3Sn intermetallic phase. CATAL COMMUN 2013. [DOI: 10.1016/j.catcom.2012.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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10
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Ando Y, Sasaki K, Su D, Adzic R. Controllable Deposition of Alloy Clusters or Nanoparticles Catalysts on Carbon Surfaces. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2011. [DOI: 10.1246/bcsj.20110008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Freitas RG, Batista EC, Castro MP, Oliveira RTS, Santos MC, Pereira EC. Ethanol Electrooxidation on Bi Submonolayers Deposited on a Pt Electrode. Electrocatalysis (N Y) 2011. [DOI: 10.1007/s12678-011-0058-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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13
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Schaltin S, Binnemans K, Fransaer J. Oscillating electrochemical reaction in copper-containing imidazolium ionic liquids. Phys Chem Chem Phys 2011; 13:15448-54. [DOI: 10.1039/c1cp20691e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Daniele S, Battistel D, Bergamin S, Bragato C. Voltammetric Determination of Glucose at Bismuth-Modified Mesoporous Platinum Microelectrodes. ELECTROANAL 2010. [DOI: 10.1002/elan.200970014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Barbero G, Macdonald JR. Transport process of ions in insulating media in the hyperbolic diffusion regime. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:051503. [PMID: 20866231 DOI: 10.1103/physreve.81.051503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 03/16/2010] [Indexed: 05/29/2023]
Abstract
We extend the microscopic Poisson-Nernst-Planck theory of the effects of mobile charge carriers, completely blocked at the electrodes, on the properties of dielectric materials by incorporating a finite speed of response propagation. The usual microscopic theory is based on the assumption that the diffusion current is given by Fick's law, relating the current density with the gradient of concentration at the same time. On the contrary we assume that the flux of diffusing particles is delayed with respect to the concentration gradient, as suggested by extended thermodynamics formulations. We show that, in the hyperbolic diffusion regime approximation, new trends for the real and imaginary parts of the small-signal electrical impedance of a dielectric containing ions versus the frequency of the applied voltage are expected when the delay time is comparable with the Debye relaxation time. In particular, at sufficiently high frequencies the real part of the conductivity, normally independent of frequency, decreases toward zero because of the finite, rather than the infinite propagation speed present in the hyperbolic diffusion regime model.
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Affiliation(s)
- G Barbero
- Dipartimento di Fisica and C.N.I.S.M., Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
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16
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Mamuru SA, Ozoemena KI, Fukuda T, Kobayashi N. Iron(ii) tetrakis(diaquaplatinum)octacarboxyphthalocyanine supported on multi-walled carbon nanotube platform: an efficient functional material for enhancing electron transfer kinetics and electrocatalytic oxidation of formic acid. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm02210a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Kiss IZ, Munjal N, Martin RS. Synchronized Current Oscillations of Formic Acid Electro-oxidation in a Microchip-based Dual-Electrode Flow Cell. Electrochim Acta 2009; 55:395-403. [PMID: 20160883 PMCID: PMC2772206 DOI: 10.1016/j.electacta.2009.02.094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigate the oscillatory electro-oxidation of formic acid on platinum in a microchip-based dual-electrode cell with microfluidic flow control. The main dynamical features of current oscillations on single Pt electrode that had been observed in macro-cells are reproduced in the microfabricated electrochemical cell. In dual-electrode configuration nearly in-phase synchronized current oscillations occur when the reference/counter electrodes are placed far away from the microelectrodes. The synchronization disappears with close reference/counter electrode placements. We show that the cause for synchronization is weak albeit important, bidirectional electrical coupling between the electrodes; therefore the unidirectional mass transfer interactions are negligible. The experimental design enables the investigation of the dynamical behavior in micro-electrode arrays with well-defined control of flow of the electrolyte in a manner where the size and spacing of the electrodes can be easily varied.
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Affiliation(s)
- István Z. Kiss
- Saint Louis University, Department of Chemistry, 3501 Laclede Ave., St. Louis, MO 63103
| | - Neil Munjal
- Saint Louis University, Department of Chemistry, 3501 Laclede Ave., St. Louis, MO 63103
| | - R. Scott Martin
- Saint Louis University, Department of Chemistry, 3501 Laclede Ave., St. Louis, MO 63103
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18
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Bonnefont A, Morschl R, Bauer P, Krischer K. Electrochemical impedance spectroscopy of patterned steady states on electrode surfaces. Electrochim Acta 2009. [DOI: 10.1016/j.electacta.2009.03.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Chen W, Xu LP, Chen S. Enhanced electrocatalytic oxidation of formic acid by platinum deposition on ruthenium nanoparticle surfaces. J Electroanal Chem (Lausanne) 2009. [DOI: 10.1016/j.jelechem.2009.03.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Uhm S, Lee HJ, Lee J. Understanding underlying processes in formic acid fuel cells. Phys Chem Chem Phys 2009; 11:9326-36. [DOI: 10.1039/b909525j] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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22
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Skogvold S, Mikkelsen Ø. Electrochemical Properties and Range of Application of Mixed Gold Bismuth Electrodes. ELECTROANAL 2008. [DOI: 10.1002/elan.200804285] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Methanol tolerant oxygen-reduction activity of carbon supported platinum–bismuth bimetallic nanoparticles. J APPL ELECTROCHEM 2008. [DOI: 10.1007/s10800-008-9638-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Lee JK, Lee J, Han J, Lim TH, Sung YE, Tak Y. Influence of Au contents of AuPt anode catalyst on the performance of direct formic acid fuel cell. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.12.031] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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The external-pulse introduced pattern in a system with a closer reference electrode and a quasi-one-dimensional ribbon working electrode. Electrochim Acta 2007. [DOI: 10.1016/j.electacta.2007.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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27
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Daniele S, Bergamin S. Preparation and voltammetric characterisation of bismuth-modified mesoporous platinum microelectrodes. Application to the electrooxidation of formic acid. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.02.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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28
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Mukouyama Y, Kikuchi M, Samjeské G, Osawa M, Okamoto H. Potential Oscillations in Galvanostatic Electrooxidation of Formic Acid on Platinum: A Mathematical Modeling and Simulation. J Phys Chem B 2006; 110:11912-7. [PMID: 16800494 DOI: 10.1021/jp061129j] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have modeled temporal potential oscillations during the electrooxidation of formic acid on platinum on the basis of the experimental results obtained by time-resolved surface-enhanced infrared absorption spectroscopy (J. Phys. Chem. B 2005, 109, 23509). The model was constructed within the framework of the so-called dual-path mechanism; a direct path via a reactive intermediate and an indirect path via strongly bonded CO formed by dehydration of formic acid. The model differs from earlier ones in the intermediate in the direct path. The reactive intermediate in this model is formate, and the oxidation of formate to CO2 is rate-determining. The reaction rate of the latter process is represented by a second-order rate equation. Simulations using this model well reproduce the experimentally observed oscillation patterns and the temporal changes in the coverages of the adsorbed formate and CO. Most properties of the voltammetric behavior of formic acid, including the potential dependence of adsorbate coverages and a negative differential resistance, are also reproduced.
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Affiliation(s)
- Yoshiharu Mukouyama
- College of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama 350-0394, Japan.
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29
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Chen W, Kim J, Sun S, Chen S. Electro-oxidation of formic acid catalyzed by FePt nanoparticles. Phys Chem Chem Phys 2006; 8:2779-86. [PMID: 16763712 DOI: 10.1039/b603045a] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrocatalytic oxidation of formic acid at a gold electrode functionalized with FePt nanoparticles was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a mixed solution of 0.1 M HCOOH and 0.1 M HClO4. The FePt bimetallic nanoparticles, with a mean diameter of 3 nm, were prepared by a chemical reduction method. The Au/FePt nanostructured electrode was prepared firstly by the deposition of FePt nanoparticles onto a clean Au electrode surface, followed by ultraviolet ozone treatment to remove the organic coating. In CV measurements, two well-defined anodic peaks were observed at +0.20 and +0.51 V (vs. a Ag/AgCl quasi-reference). The anodic peak at +0.20 V was attributed to the oxidation of HCOOH to CO2 on surface unblocked by CO, whereas the peak at +0.51 V was ascribed to the oxidation of surface-adsorbed CO (an intermediate product of HCOOH oxidation) and further oxidation of bulk HCOOH. From the onset potential and current density of the electro-oxidation of HCOOH, FePt nanoparticles exhibit excellent electrocatalytic activities as compared to Pt and other metal alloys. EIS measurements were carried out to further examine the reaction kinetics involved in the HCOOH electro-oxidation. The EIS responses were found to be strongly dependent on electrode potentials. At potentials more positive than -0.25 V (vs. Ag/AgCl), pseudo-inductive behavior was typically observed. At potentials between +0.3 and +0.5 V, the impedance response was found to reverse from the first quadrant to the second quadrant; such negative Faradaic impedance was indicative of the presence of an inductive component due to the oxidation of surface-adsorbed CO. The impedance responses returned to normal behavior at more positive potentials (+0.6 to +0.9 V). The mechanistic variation was attributed to the formation of different intermediates (CO or oxygen containing species) on the electrode surface in different potential regions. Two equivalent circuits were proposed to model these impedance behaviors.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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30
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Kang S, Lee J, Lee JK, Chung SY, Tak Y. Influence of Bi Modification of Pt Anode Catalyst in Direct Formic Acid Fuel Cells. J Phys Chem B 2006; 110:7270-4. [PMID: 16599497 DOI: 10.1021/jp056753v] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The influence of Bi modification of Pt anode catalyst on the performance of direct formic acid fuel cells was investigated. Compared with the unmodified Pt anode, the Bi modified Pt (PtBi(m)) electrode prepared by under-potential deposition (UPD) caused faster electrocatalytic oxidation of formic acid at the same value of the overpotential, and thus, PtBi(m) resulted in an increase in the power performance of direct formic acid fuel cells. Electrochemical impedance spectra helped to explain the difference of performance between the unmodified Pt and Bi modified Pt electrodes. Solution conductivity and dehydration phenomena occurring in highly concentrated formic acid solutions can also explain the higher power performance of PtBi(m).
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Affiliation(s)
- Sungjin Kang
- Department of Chemical Engineering, Inha University, Inchon 402-751, South Korea
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31
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Uhm S, Yun Y, Tak Y, Lee J. EQCM analysis of Bi oxidation mechanism on a Pt electrode. Electrochem commun 2005. [DOI: 10.1016/j.elecom.2005.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Chen A, La Russa DJ, Miller B. Effect of the iridium oxide thin film on the electrochemical activity of platinum nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:9695-9702. [PMID: 15491204 DOI: 10.1021/la0484873] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The influence of the iridium oxide thin film on the electrocatalytic properties of platinum nanoparticles was investigated using the electro-oxidation of methanol and CO as a probe. The presence of the IrO(2) thin film leads to the homogeneous dispersion of Pt nanoparticles. For comparison, polycrystalline platinum and Pt nanoparticles dispersed on a Ti substrate in the absence of an IrO(2) layer (Ti/Pt) were also investigated in this study. Inverted and enhanced CO bipolar peaks were observed using an in situ electrochemical Fourier transform infrared technique during the methanol oxidation on the Pt nanoparticles dispersed on a Ti substrate. Electrochemical impedance studies showed that the charge transfer resistance was significantly lower for the Ti/IrO(2)/Pt electrode compared with that of the massive Pt and Ti/Pt nanoparticles. The presence of the IrO(2) thin film not only greatly increases the active surface area but also promotes CO oxidation at a much lower electrode potential, thus, significantly enhancing the electrocatalytic activity of Pt nanoparticles toward methanol electro-oxidation.
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Affiliation(s)
- Aicheng Chen
- Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada.
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Sadkowski A. On specific properties of electrochemical immittance close to discontinuity points. Electrochim Acta 2004. [DOI: 10.1016/j.electacta.2004.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Wagner N, Schulze M. Change of electrochemical impedance spectra during CO poisoning of the Pt and Pt–Ru anodes in a membrane fuel cell (PEFC). Electrochim Acta 2003. [DOI: 10.1016/s0013-4686(03)00528-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Lee J, Christoph J, Eiswirth M, Ertl G. Spatiotemporal Mixed-Mode Oscillations on a Ring Electrode. ACTA ACUST UNITED AC 2002. [DOI: 10.1524/zpch.2002.216.4.479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We present spatiotemporal mixed-mode oscillations in the electrocatalytic oxidation of formic acid on a platinum ring electrode modified by bismuth deposition. On the anodic scan, we observed spontaneous reversal of direction of a rotating activation pulse occurring repeatedly at the same location of the ring. In the constant potential method, spatiotemporal mixed-mode oscillations of pulse reversal were shown to constitute a fraction of an ordered Farey sequence.
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