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

Perovskites exhibit considerable potential as catalysts for various applications, yet their performance modulation in the carbon dioxide reduction reaction (CO 2 RR) remains underexplored. In this study, we report a strategy to enhance the electrocatalytic carbon dioxide (CO 2 ) reduction activity via Ce-doped La 2 CuO 4 (LCCO) and Sr-doped La 2 CuO 4 (LSCO) perovskite oxides. Specifically, compared to pure phase La 2 CuO 4 (LCO), the Faraday efficiency (FE) for CH 4 of LCCO at −1.4 V vs. RHE (reversible hydrogen electrode) is improved from 38.9% to 59.4%, and the FE CO 2 RR 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 CH 4 , compared to the pristine La 2 CuO 4 . X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and double-layer capacitance ( C dl ) outcomes reveal that heteroatom-doped perovskites exhibit more oxygen vacancies and higher electrochemical active surface areas, leading to a significant improvement in the CO 2 RR 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. Doping La 2 CuO 4 with A-site elements creates abundant active sites and oxygen vacancies, boosting CO 2 electroreduction selectivity by altering electronic structure and intermediate binding energies.