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Laws K, Buckingham MA, Aldous L. Self-assembled monolayers for electrostatic electrocatalysis and enhanced electrode stability in thermogalvanic cells. Chem Sci 2024; 15:6958-6964. [PMID: 38725507 PMCID: PMC11077577 DOI: 10.1039/d3sc06766a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 04/02/2024] [Indexed: 05/12/2024] Open
Abstract
Waste heat is ubiquitous; as such, sustainable and long-lasting devices are required to convert it into more useful forms of energy that can make use of this abundant potential resource. Thermogalvanic cells (or thermocells) can use the thermoelectrochemical properties of redox couples to achieve this; entropy-driven redox reactions allow them to act as liquid thermoelectrics. However, excellent electrocatalysis at the electrode surface is required for optimum conversion efficiency. Serendipitous observation of Nafion-based electrocatalysis prompted the exploration of electrostatically charged self-assembled monolayers (SAMs) inside a thermocell. Both electrostatic electrocatalysis and improved electrode stability were observed; in an aqueous K3[Fe(CN)6]/K4[Fe(CN)6]-based cell, modification with (3-trimethylammonium bromide)thiopropane resulted in higher electrical power, and protection against [Fe(CN)6]3-/4--induced gold passivation, relative to bare gold. Molecular-based electrostatic electrocatalysis could be an alternative to precious metal-based nanomaterial electrocatalysis, and could be integrated with (nano)carbon-based electrodes to further enhance the ability of thermogalvanic and other electrochemical energy conversion devices, e.g. redox flow batteries.
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Affiliation(s)
- Kristine Laws
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
| | - Mark A Buckingham
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
| | - Leigh Aldous
- Department of Chemistry, Britannia House, King's College London London SE1 1DB UK
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Xu Y, Zhang L, Chen W, Cui H, Cai J, Chen Y, Feliu JM, Herrero E. Boosting Oxygen Reduction at Pt(111)|Proton Exchange Ionomer Interfaces through Tuning the Microenvironment Water Activity. ACS APPLIED MATERIALS & INTERFACES 2024; 16:4540-4549. [PMID: 38227931 DOI: 10.1021/acsami.3c14208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
A proton exchange ionomer is one of the most important components in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFCs). It acts as both a proton conductor and a binder for nanocatalysts and carbon supports. The structure and the wetting conditions of the MEAs have a great impact on the microenvironment at the three-phase interphases in the MEAs, which can significantly influence the electrode kinetics such as the oxygen reduction reaction (ORR) at the cathode. Herein, by using the Pt(111)|X ionomer interface as a model system (X = Nafion, Aciplex, D72), we find that higher drying temperature lowers the onset potential for sulfonate adsorption and reduces apparent ORR current, while the current wave for OHad formation drops and shifts positively. Surprisingly, the intrinsic ORR activity is higher after properly correcting the blocking effect of Pt active sites by sulfonate adsorption and the poly(tetrafluoroethylene) (PTFE) skeleton. These results are well explained by the reduced water activity at the interfaces induced by the ionomer/PTFE, according to the mixed potential effect. Implications for how to prepare MEAs with improved ORR activity are provided.
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Affiliation(s)
- Yujun Xu
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Lulu Zhang
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Haowen Cui
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jun Cai
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yanxia Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Juan M Feliu
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
| | - Enrique Herrero
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
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Liu BY, Zhen EF, Zhang LL, Cai J, Huang J, Chen YX. The pH-Induced Increase of the Rate Constant for HER at Au(111) in Acid Revealed by Combining Experiments and Kinetic Simulation. Anal Chem 2024; 96:67-75. [PMID: 38153001 DOI: 10.1021/acs.analchem.3c02818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Origins of pH effects on the kinetics of electrocatalytic reactions involving the transfer of both protons and electrons, including the hydrogen evolution reaction (HER) considered in this study, are heatedly debated. By taking the HER at Au(111) in acid solutions of different pHs and ionic concentrations as the model systems, herein, we report how to derive the intrinsic kinetic parameters of such reactions and their pH dependence through the measurement of j-E curves and the corresponding kinetic simulation based on the Frumkin-Butler-Volmer theory and the modified Poisson-Nernst-Planck equation. Our study reveals the following: (i) the same set of kinetic parameters, such as the standard activation Gibbs free energy, charge transfer coefficient, and Gibbs adsorption energy for Had at Au(111), can simulate well all the j-E curves measured in solutions with different pH and temperatures; (ii) on the reversible hydrogen electrode scale, the intrinsic rate constant increases with the increase of pH, which is in contrast with the decrease of the HER current with the increase of pH; and (iii) the ratio of the rate constants for HER at Au(111) in x M HClO4 + (0.1 - x) M NaClO4 (pH ≤ 3) deduced before properly correcting the electric double layer (EDL) effects to the ones estimated with EDL correction is in the range of ca. 10 to 40, and even in a solution of x M HClO4 + (1 - x) M NaClO4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL correction. The importance of proper correction of the EDL effects as well as several other important factors on unveiling the intrinsic pH-dependent reaction kinetics are discussed to help converge our analysis of pH effects in electrocatalysis.
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Affiliation(s)
- Bing-Yu Liu
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Er-Fei Zhen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lu-Lu Zhang
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Cai
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Huang
- Institute of Energy and Climate Research, IEK-13: Theory and Computation of Energy Materials, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Theorie Elektrokatalytischer Grenzflächen, Fakultät für Georessourcen und Materialtechnik, RWTH Aachen University, 52062 Aachen, Germany
| | - Yan-Xia Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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He Z, Ajmal M, Zhang M, Liu X, Huang Z, Shi C, Gao R, Pan L, Zhang X, Zou J. Progress in Manipulating Dynamic Surface Reconstruction via Anion Modulation for Electrocatalytic Water Oxidation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2304071. [PMID: 37551998 PMCID: PMC10582449 DOI: 10.1002/advs.202304071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/12/2023] [Indexed: 08/09/2023]
Abstract
The development of efficient and economical electrocatalysts for oxygen evolution reaction (OER) is of paramount importance for the sustainable production of renewable fuels and energy storage systems; however, the sluggish OER kinetics involving multistep four proton-coupled electron transfer hampers progress in these systems. Fortunately, surface reconstruction offers promising potential to improve OER catalyst design. Anion modulation plays a crucial role in controlling the extent of surface reconstruction and positively persuading the reconstructed species' performances. This review starts by providing a general explanation of how various types of anions can trigger dynamic surface reconstruction and create different combinations with pre-catalysts. Next, the influences of anion modulation on manipulating the surface dynamic reconstruction process are discussed based on the in situ advanced characterization techniques. Furthermore, various effects of survived anionic groups in reconstructed species on water oxidation activity are further discussed. Finally, the challenges and prospects for the future development directions of anion modulation for redirecting dynamic surface reconstruction to construct highly efficient and practical catalysts for water oxidation are proposed.
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Affiliation(s)
- Zexing He
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Muhammad Ajmal
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Minghui Zhang
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Xiaokang Liu
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Zhen‐Feng Huang
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Chengxiang Shi
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Ruijie Gao
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Lun Pan
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Xiangwen Zhang
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
| | - Ji‐Jun Zou
- Key Laboratory for Green Chemical Technology of the Ministry of Education, Institute of Molecular Plus, School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China
- Collaborative Innovative Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China
- Zhejiang Institute of Tianjin UniversityTianjin UniversityNingboZhejiang315201China
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