The in situ study of surface species and structures of oxide-derived copper catalysts for electrochemical CO2 reduction

Chunjun Chen; Xupeng Yan; Yahui Wu; Shoujie Liu; Xiaofu Sun; Qinggong Zhu; Rongjuan Feng; Tianbin Wu; Qingli Qian; Huizhen Liu; Lirong Zheng; Jing Zhang; Buxing Han

doi:10.1039/d1sc00042j

The in situ study of surface species and structures of oxide-derived copper catalysts for electrochemical CO₂ reduction

Chem Sci. 2021 Mar 16;12(16):5938-5943. doi: 10.1039/d1sc00042j. eCollection 2021 Apr 28.

Authors

Chunjun Chen^{1

2}, Xupeng Yan^{1

2}, Yahui Wu^{1

2}, Shoujie Liu³, Xiaofu Sun^{1

2}, Qinggong Zhu¹, Rongjuan Feng¹, Tianbin Wu¹, Qingli Qian¹, Huizhen Liu¹, Lirong Zheng⁴, Jing Zhang⁴, Buxing Han^{1

2

5

6}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 P. R. China hanbx@iccas.ac.cn.
² University of Chinese Academy of Sciences Beijing 100049 China.
³ Chemistry and Chemical Engineering of Guangdong Laboratory Shantou 515063 China.
⁴ Institute of High Energy Physics, Chinese Academy of Sciences Beijing 100049 China.
⁵ Physical Science Laboratory, Huairou National Comprehensive Science Center Beijing 101400 China.
⁶ Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University Shanghai 200062 China.

Abstract

Oxide-derived copper (OD-Cu) has been discovered to be an effective catalyst for the electroreduction of CO₂ to C2+ products. The structure of OD-Cu and its surface species during the reaction process are interesting topics, which have not yet been clearly discussed. Herein, in situ surface-enhanced Raman spectroscopy (SERS), operando X-ray absorption spectroscopy (XAS), and ¹⁸O isotope labeling experiments were employed to investigate the surface species and structures of OD-Cu catalysts during CO₂ electroreduction. It was found that the OD-Cu catalysts were reduced to metallic Cu(0) in the reaction. CuO _x species existed on the catalyst surfaces during the CO₂RR, which resulted from the adsorption of preliminary intermediates (such as *CO₂ and *OCO^-) on Cu instead of on the active sites of the catalyst. It was also found that abundant interfaces can be produced on OD-Cu, which can provide heterogeneous CO adsorption sites (strong binding sites and weak binding sites), leading to outstanding performance for obtaining C2+ products. The Faradaic efficiency (FE) for C2+ products reached as high as 83.8% with a current density of 341.5 mA cm^-2 at -0.9 V vs. RHE.