Hierarchical Copper with Inherent Hydrophobicity Mitigates Electrode Flooding for High-Rate CO<sub>2</sub> Electroreduction to Multicarbon Products
Zhuang‐Zhuang Niu, Fei‐Yue Gao, Xiaolong Zhang, Peng‐Peng Yang, Ren Liu, Li‐Ping Chi, Zhi‐Zheng Wu, Shuai Qin, Xingxing Yu, Min‐Rui Gao
Abstract
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.