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Promoting CO2 Electroreduction to Multi-Carbon Products by Hydrophobicity-Induced Electro-Kinetic Retardation |
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| Authors: | Mengjiao Zhuansun Yue Liu Ruihu Lu Fan Zeng Zhanyou Xu Ying Wang Prof. Yaoyue Yang Prof. Ziyun Wang Prof. Gengfeng Zheng Prof. Yuhang Wang |
| Affiliation: | 1. Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Advanced Negative Carbon Technologies, Soochow University, Suzhou, 215123 China These authors contributed equally to this work.;2. School of Chemistry and Environment, Southwest Minzu University, Chengdu, 610041 China These authors contributed equally to this work.;3. School of Chemical Sciences, University of Auckland, Auckland, 1010 New Zealand;4. Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Advanced Negative Carbon Technologies, Soochow University, Suzhou, 215123 China;5. Department of Chemistry, Chinese University of Hong Kong, N.T. Hong Kong SAR, 999077 China;6. School of Chemistry and Environment, Southwest Minzu University, Chengdu, 610041 China;7. Laboratory of Advanced Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438 China |
| Abstract: | Advancing the performance of the Cu-catalyzed electrochemical CO2 reduction reaction (CO2RR) is crucial for its practical applications. Still, the wettable pristine Cu surface often suffers from low exposure to CO2, reducing the Faradaic efficiencies (FEs) and current densities for multi-carbon (C2+) products. Recent studies have proposed that increasing surface availability for CO2 by cation-exchange ionomers can enhance the C2+ product formation rates. However, due to the rapid formation and consumption of *CO, such promotion in reaction kinetics can shorten the residence of *CO whose adsorption determines C2+ selectivity, and thus the resulting C2+ FEs remain low. Herein, we discover that the electro-kinetic retardation caused by the strong hydrophobicity of quaternary ammonium group-functionalized polynorbornene ionomers can greatly prolong the *CO residence on Cu. This unconventional electro-kinetic effect is demonstrated by the increased Tafel slopes and the decreased sensitivity of *CO coverage change to potentials. As a result, the strongly hydrophobic Cu electrodes exhibit C2+ Faradaic efficiencies of ≈90 % at a partial current density of 223 mA cm−2, more than twice of bare or hydrophilic Cu surfaces. |
| Keywords: | C2+ Product CO2 Electroreduction Copper Catalyst Electro-Kinetic Retardation Hydrophobicity |