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Iesalnieks M, Vanags M, Alsiņa LL, Eglītis R, Grīnberga L, Sherrell PC, Šutka A. Efficient Decoupled Electrolytic Water Splitting in Acid through Pseudocapacitive TiO 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401261. [PMID: 38742588 DOI: 10.1002/advs.202401261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/30/2024] [Indexed: 05/16/2024]
Abstract
Water electrolysis remains a key component in the societal transition to green energy. Membrane electrolyzers are the state-of-the-art technology for water electrolysis, relying on 80 °C operation in highly alkaline electrolytes, which is undesirable for many of the myriad end-use cases for electrolytic water splitting. Herein, an alternative water electrolysis process, decoupled electrolysis, is described which performed in mild acidic conditions with excellent efficiencies. Decoupled electrolysis sequentially performs the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), at the same catalyst. Here, H+ ions generated from the OER are stored through pseudocapacitive (redox) charge storage, and released to drive the HER. Here, decoupled electrolysis is demonstrated using cheap, abundant, TiO2 for the first time. To achieve decoupled acid electrolysis, ultra-small anatase TiO2 particles (4.5 nm diameter) are prepared. These ultra-small TiO2 particles supported on a carbon felt electrode show a highly electrochemical surface area with a capacitance of 375 F g-1. When these electrodes are tested for decoupled water splitting an overall energy efficiency of 52.4% is observed, with excellent stability over 3000 cycles of testing. This technology can provide a viable alternative to membrane electrolyzers-eliminating the need for highly alkaline electrolytes and elevated temperatures.
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Affiliation(s)
- Mairis Iesalnieks
- Institute of Materials and Surface Engineering, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Street 3/7, Riga, LV-1048, Latvia
| | - Mārtiņš Vanags
- Institute of Materials and Surface Engineering, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Street 3/7, Riga, LV-1048, Latvia
| | - Linda Laima Alsiņa
- Institute of Materials and Surface Engineering, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Street 3/7, Riga, LV-1048, Latvia
| | - Raivis Eglītis
- Institute of Materials and Surface Engineering, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Street 3/7, Riga, LV-1048, Latvia
| | - Līga Grīnberga
- Institute of Solid State Physics, University of Latvia, Riga, LV-1063, Latvia
| | - Peter C Sherrell
- Applied Chemistry & Environmental Science, School of Science, RMIT University, 124 La Trobe St, Melbourne, 3000, Australia
| | - Andris Šutka
- Institute of Materials and Surface Engineering, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Street 3/7, Riga, LV-1048, Latvia
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Imhof T, Della Bella RKF, Stühmeier BM, Gasteiger HA, Ledendecker M. Towards a realistic prediction of catalyst durability from liquid half-cell tests. Phys Chem Chem Phys 2023. [PMID: 37470348 DOI: 10.1039/d3cp02847j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Liquid half-cell measurements provide a convenient laboratory method for determining relevant parameters of electro-catalysts applied in e.g. polymer electrolyte membrane fuel cells. While these measurements may be effective in certain contexts, their applicability to real-world systems, such as single-cells in a membrane electrode assembly (MEA) configuration, is not always clear. This is particularly true when assessing the stability of these systems through accelerated stress tests (ASTs). Due to different electrode compositions and operating conditions, nanoscale degradation proceeds differently. Nevertheless, given the high demands of MEA measurements in terms of time, testing equipment complexity, and amount of catalyst material, application-relevant predictions of catalyst durability from liquid half-cell tests are highly desirable. This study combines electrochemical and nanoparticle analysis based on transmission electron microscopy to conduct a typical voltage cycling AST for rotating disc electrode (RDE) measurements, showing that the loss of the electrochemically active surface area (ECSA) of the used Pt/Vulcan catalyst is strongly enhanced at 80 °C compared to room temperature, which goes along with increased nanoparticle coarsening. Additionally, a high ionomer/carbon mass ratio (I/C = 0.7) accelerates the ECSA loss, and further investigations of its influence suggest a combination of several factors, including the high local proton concentration and the presence of adsorbing anions. At the same temperature (80 °C) and I/C ratio (0.7), the ECSA loss vs. AST cycle number of the Pt/Vulcan catalyst is essentially identical for a voltage cycling AST conducted in either an RDE half-cell or an MEA configuration, suggesting that liquid electrolyte half-cell based ASTs can provide application-relevant results. Thus, our study points out a way for predicting the stability of electro-catalysts in MEAs based on RDE experiments that require less specialized equipment and only μg-quantities of catalysts.
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Affiliation(s)
- Timo Imhof
- Technical University of Darmstadt, Peter-Grünberg-Strasse 10, 64287 Darmstadt, Germany.
| | | | - Björn M Stühmeier
- Technical University of Munich, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Hubert A Gasteiger
- Technical University of Munich, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Marc Ledendecker
- Technical University of Darmstadt, Peter-Grünberg-Strasse 10, 64287 Darmstadt, Germany.
- Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany.
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Liu D, Zhang J, Liu D, Li T, Yan Y, Wei X, Yang Y, Yan S, Zou Z. N-Doped Graphene-Coated Commercial Pt/C Catalysts toward High-Stability and Antipoisoning in Oxygen Reduction Reaction. J Phys Chem Lett 2022; 13:2019-2026. [PMID: 35195426 DOI: 10.1021/acs.jpclett.1c04005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Stability and antipoisoning effects are the main challenges for the application of commercial Pt/C catalysts. Herein, we soaked and adsorbed polydopamine to coat Pt particles on commercial Pt/C and subsequently converted the coatings to few-layer N-doped graphene by calcination to produce Pt/C@NC. The coatings effectively block the direct contact of Pt nanoparticles and electrolyte, thus enhancing the catalyst stability by avoiding Ostwald ripening and suppressing the competitive adsorption of toxicants, contributing to the enhancement of the antipoisoning ability. More importantly, the coatings do not hurt the oxygen reduction reaction (ORR) activity of commercial Pt/C, which exhibits a half wave potential of 0.84 V in an acidic electrolyte. The spectroscopic and theoretical results confirmed that the coatings originate from a strong Pt bonding to pyridinic N of N-doped graphene and that the high ORR activity results from the coordinately unsaturated carbon atoms, as the real ORR active sites, to strongly capture electrons from Pt.
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Affiliation(s)
- Depei Liu
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
- Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Jie Zhang
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Duanduan Liu
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
- Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Taozhu Li
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Yuandong Yan
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Xinying Wei
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Yandong Yang
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Shicheng Yan
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Zhigang Zou
- Eco-materials and Renewable Energy Research Center (ERERC), Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
- Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
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MA Y, KAJIMA H, SHIMASAKI Y, NAGAI T, NAPPORN TW, WADA H, KURODA K, KURODA Y, ISHIHARA A, MITSUSHIMA S. Degradation Analysis of Pt/Nb–Ti<sub>4</sub>O<sub>7</sub> as PEFC Cathode Catalysts with Controlled Arc Plasma–deposited Platinum Content. ELECTROCHEMISTRY 2022. [DOI: 10.5796/electrochemistry.22-00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Yongbing MA
- Graduate School of Engineering Science, Yokohama National University
| | - Hirokata KAJIMA
- Graduate School of Engineering Science, Yokohama National University
| | - Yuta SHIMASAKI
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University
| | - Takaaki NAGAI
- Advanced Chemical Energy Research Center, Institute of Advanced Sciences, Yokohama National University
| | - Teko W. NAPPORN
- Advanced Chemical Energy Research Center, Institute of Advanced Sciences, Yokohama National University
| | - Hiroaki WADA
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University
| | - Kazuyuki KURODA
- Kagami Memorial Research Institute for Materials Science and Technology, Waseda University
| | - Yoshiyuki KURODA
- Graduate School of Engineering Science, Yokohama National University
| | - Akimitsu ISHIHARA
- Advanced Chemical Energy Research Center, Institute of Advanced Sciences, Yokohama National University
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