Engineering highly selective CO2 electroreduction in Cu-based perovskites through A-site cation manipulation.

Abstract

Perovskites exhibit considerable potential as catalysts for various applications, yet their performance modulation in the carbon dioxide reduction reaction (CO2RR) remains underexplored. In this study, we report a strategy to enhance the electrocatalytic carbon dioxide (CO2) reduction activity via Ce-doped La2CuO4 (LCCO) and Sr-doped La2CuO4 (LSCO) perovskite oxides. Specifically, compared to pure phase La2CuO4 (LCO), the Faraday efficiency (FE) for CH4 of LCCO at -1.4 V vs. RHE (reversible hydrogen electrode) is improved from 38.9% to 59.4%, and the FECO2RR of LSCO increased from 68.8% to 85.4%. In situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy spectra results indicate that the doping of A-site ions promotes the formation of *CHO and *HCOO, which are key intermediates in the production of CH4, compared to the pristine La2CuO4. X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and double-layer capacitance (Cdl) outcomes reveal that heteroatom-doped perovskites exhibit more oxygen vacancies and higher electrochemical active surface areas, leading to a significant improvement in the CO2RR performance of the catalysts. This study systematically investigates the effect of A-site ion doping on the catalytic activity center Cu and proposes a strategy to improve the catalytic performance of perovskite oxides.