Degradation study on tin- and bismuth-based gas-diffusion electrodes during electrochemical CO_(2) reduction in highly alkaline media

作     者：Fabian Bienen Armin Lowe Joachim Hildebrand Sebastian Hertle Dana Schonvogel Dennis Kopljar Norbert Wagner Elias Klemm Kaspar Andreas Friedrich Fabian Bienen;Armin L?we;Joachim Hildebrand;Sebastian Hertle;Dana Schonvogel;Dennis Kopljar;Norbert Wagner;Elias Klemm;Kaspar Andreas Friedrich

作者机构：Institute of Engineering ThermodynamicsGerman Aerospace CenterPfaffenwaldring 38-4070569 StuttgartGermany Institute of Building EnergeticsThermal Engineering and Energy StorageUniversity of StuttgartPfaffenwaldring 3170569 StuttgartGermany Institute of Technical ChemistryUniversity of StuttgartPfaffenwaldring 5570569 StuttgartGermany Institute of Engineering ThermodynamicsGerman Aerospace CenterCarl-von-Ossietzky-Straße 1526129 OldenburgGermany 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2021年第30卷第11期

页      面：367-376,I0008页

核心收录：

学科分类：0820[工学-石油与天然气工程] 083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0808[工学-电气工程] 081704[工学-应用化学] 081705[工学-工业催化] 0817[工学-化学工程与技术] 08[工学] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 

基　　金：Parts of this work were funded by the German Federation of Industrial Research Associations(EWN03176/18) 

主　　题：Electrochemical CO_(2)reduction Heterogeneous catalysis Gas-diffusion electrode Electrochemical impedance spectroscopy Catalyst leaching 

摘      要：This work investigated the degradation of tin – based gas-diffusion electrodes (GDE) and also a promising Bi2O3 GDE in electrochemical CO_(2) reduction in highly alkaline media which has not been studied before. The contributions of the electrode wetting (or flooding, if excessively) and catalyst leaching on the degradation were analyzed. Therefore, electrochemical impedance spectroscopy was used to monitor the wetted surface area of the GDE in combination with post-mortem analysis of the penetration depth by visualizing the electrolyte’s cation in the GDE cross-section. Furthermore, to reveal a possible degradation of the electrocatalyst, its distribution was mapped in the GDEs cross-section after operation while the catholyte was additionally analyzed via ICP-MS. The results clearly demonstrate that the SnO_(2) catalyst dissolves in the reaction zone inside the GDE and might be partially redeposited near the GDEs surface. Since the redeposition process occurs only partially a steady loss of catalyst was observed impeding a clear distinction of the two degradation phenomena. Nevertheless, the deterioration of the electrode performance measured as faraday efficiency (FE) of the parasitic hydrogen evolution reaction (HER) qualitatively correlates with the differential double layer capacitance (Cdl). A significant difference of the rate of increase for the hydrogen FE and Cdl can be ascribed to the superposition of both above-mentioned degradation mechanisms. The demonstrated instability of SnO_(2) contrasts with the behavior of Bi2O3 GDE which is stabilized during CO_(2) conversion by redeposition of the diluted dissolved species as metallic Bi which is active for the CO_(2) reduction reaction.