Electroreduction of CO2 to Formate on a Copper-Based Electrocatalyst at High Pressures with High Energy Conversion Efficiency

Jiachen Li; Yun Kuang; Yongtao Meng; Xin Tian; Wei-Hsuan Hung; Xiao Zhang; Aowen Li; Mingquan Xu; Wu Zhou; Ching-Shun Ku; Ching-Yu Chiang; Guanzhou Zhu; Jinyu Guo; Xiaoming Sun; Hongjie Dai

doi:10.1021/jacs.0c00122

Electroreduction of CO₂ to Formate on a Copper-Based Electrocatalyst at High Pressures with High Energy Conversion Efficiency

J Am Chem Soc. 2020 Apr 22;142(16):7276-7282. doi: 10.1021/jacs.0c00122. Epub 2020 Apr 10.

Authors

Jiachen Li^{1

2}, Yun Kuang^{1

3}, Yongtao Meng¹, Xin Tian¹, Wei-Hsuan Hung^{1

4}, Xiao Zhang¹, Aowen Li⁵, Mingquan Xu⁵, Wu Zhou⁵, Ching-Shun Ku⁶, Ching-Yu Chiang⁶, Guanzhou Zhu¹, Jinyu Guo¹, Xiaoming Sun³, Hongjie Dai¹

Affiliations

¹ Department of Chemistry, Stanford University, Stanford, California 94305, United States.
² Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
³ State Key Laboratory of Chemical Resource Engineering and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
⁴ Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan.
⁵ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
⁶ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.

PMID: 32250611
DOI: 10.1021/jacs.0c00122

Abstract

Electrocatalytic CO₂ reduction (CO₂RR) to valuable fuels is a promising approach to mitigate energy and environmental problems, but controlling the reaction pathways and products remains challenging. Here a novel Cu₂O nanoparticle film was synthesized by square-wave (SW) electrochemical redox cycling of high-purity Cu foils. The cathode afforded up to 98% Faradaic efficiency for electroreduction of CO₂ to nearly pure formate under ≥45 atm CO₂ in bicarbonate catholytes. When this cathode was paired with a newly developed NiFe hydroxide carbonate anode in KOH/borate anolyte, the resulting two-electrode high-pressure electrolysis cell achieved high energy conversion efficiencies of up to 55.8% stably for long-term formate production. While the high-pressure conditions drastically increased the solubility of CO₂ to enhance CO₂ reduction and suppress hydrogen evolution, the (111)-oriented Cu₂O film was found to be important to afford nearly 100% CO₂ reduction to formate. The results have implications for CO₂ reduction to a single liquid product with high energy conversion efficiency.