Hierarchical Copper with Inherent Hydrophobicity Mitigates Electrode Flooding for High-Rate CO2 Electroreduction to Multicarbon Products

• Published in: Journal of the American Chemical Society Vol. 143; no. 21; pp. 8011 - 8021
• Main Authors: Niu, Zhuang-Zhuang, Gao, Fei-Yue, Zhang, Xiao-Long, Yang, Peng-Peng, Liu, Ren, Chi, Li-Ping, Wu, Zhi-Zheng, Qin, Shuai, Yu, Xingxing, Gao, Min-Rui
• Format: Journal Article
• Language: English
• Published: American Chemical Society 02.06.2021
• Subjects: carbon dioxide; catalysts; electrodes; electrolytes; hydrophobicity; Setaria; value added
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.1c01190

Copper is currently the material with the most promise as catalyst to drive carbon dioxide (CO2) electroreduction to produce value-added multicarbon (C2+) compounds. However, a copper catalyst on a carbon-based gas diffusion layer electrode often has poor stabilityespecially when performing at high current densitiesowing to electrolyte flooding caused by the hydrophobicity decrease of the gas diffusion layer during operation. Here, we report a bioinspired copper catalyst on a gas diffusion layer that mimics the unique hierarchical structuring of Setaria’s hydrophobic leaves. This hierarchical copper structure endows the CO2 reduction electrode with sufficient hydrophobicity to build a robust gas–liquid–solid triple-phase boundary, which can not only trap more CO2 close to the active copper surface but also effectively resist electrolyte flooding even under high-rate operation. We consequently achieved a high C2+ production rate of 255 ± 5.7 mA cm–2 with a 64 ± 1.4% faradaic efficiency, as well as outstanding operational stability at 300 mA cm–2 over 45 h in a flow reactor, largely outperforming its wettable copper counterparts.