Tuning the Selectivity of Liquid Products of CO2RR by Cu-Ag Alloying

Yanzhi Xu; Changli Li; Yequan Xiao; Chenghui Wu; Yanming Li; Yanbo Li; Juguang Han; Qinghua Liu; Jingfu He

doi:10.1021/acsami.2c00593

Tuning the Selectivity of Liquid Products of CO₂RR by Cu-Ag Alloying

ACS Appl Mater Interfaces. 2022 Mar 9;14(9):11567-11574. doi: 10.1021/acsami.2c00593. Epub 2022 Feb 24.

Authors

Yanzhi Xu¹, Changli Li², Yequan Xiao³, Chenghui Wu², Yanming Li², Yanbo Li³, Juguang Han¹, Qinghua Liu¹, Jingfu He²

Affiliations

¹ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
² School of Materials, Sun Yat-sen University, Guangzhou, Guangdong 510275, China.
³ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China.

PMID: 35209715
DOI: 10.1021/acsami.2c00593

Abstract

The combination of Cu and Ag presents a promising way to steer the CO₂ reduction products through regulating the surface active sites. However, the difficulty in forming the CuAg alloy with a controllable atomic ratio impedes the in-depth understanding of the structure-activity relationship of CuAg catalysts. Herein, we use E-beam evaporation to synthesize a series of CuAg films with uniform distribution and controllable stoichiometry to reveal the real reaction mechanism on CuAg for the electrochemical CO₂ reduction process. Compared with Cu, the Cu_1-xAg_x (x = 0.05-0.2) alloy showed an apparent suppression of HCOOH and the ratio between C₂ liquid products (e.g., ethanol and acetate) and C₁ liquid product (HCOOH) is also increased. Operando synchrotron radiation Fourier transform infrared spectroscopy results suggest that the introduction of Ag into the Cu phase can significantly strengthen the absorbed *CO and *OCCO intermediates and suppress the O-C-O intermediates. This research provides a reliable way to inhibit the generation of HCOOH and enhance the production of liquid C₂ products during CO₂RR and presents a guideline for the future manipulation of copper catalysts by alloying.

Keywords: CO2 reduction reaction; CuAg alloy; electrocatalysis; liquid products; synchrotron radiation infrared spectroscopy.