Stabilizing Cu0–Cu+ sites by Pb-doping for highly efficient CO2 electroreduction to C2 products

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) can convert CO₂ to C₂ hydrocarbons and oxygenate over Cu-based catalysts, and has great potential to store renewable energy and close the carbon cycle. Developing a facile method to modify the local electronic structure of Cu is a useful way to design efficient catalysts. Herein, we design a Pb-doping Cu₂O catalyst with controllable Cu⁰–Cu⁺ sites. The catalyst generated a high C₂ faradaic efficiency (FE) of 83.9% with a current density of 203.8 mA cm⁻² at −1.1 V vs. RHE in a flow cell. In situ X-ray absorption spectroscopy and Raman spectroscopy revealed that the Pb doping in Cu₂O could stabilize the Cu⁰–Cu⁺ structure and enhance the CO adsorption and C–C coupling, leading to high activity for C₂ product formation. Theoretical calculations also show that Pb doping could reduce the energy barrier for both CO₂ activation and C–C coupling processes.