Engineering highly selective CO 2 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.