Engineering highly selective CO2 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<INF>2</INF>RR) remains underexplored. In this study, we report a strategy to enhance the electrocatalytic carbon dioxide (CO<INF>2</INF>) reduction activity via Ce-doped La<INF>2</INF>CuO<INF>4</INF> (LCCO) and Sr-doped La<INF>2</INF>CuO<INF>4</INF> (LSCO) perovskite oxides. Specifically, compared to pure phase La<INF>2</INF>CuO<INF>4</INF> (LCO), the Faraday efficiency (FE) for CH<INF>4</INF> of LCCO at -1.4 V vs. RHE (reversible hydrogen electrode) is improved from 38.9% to 59.4%, and the FE<INF>CO<INF>2</INF>RR</INF> 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<INF>4</INF>, compared to the pristine La<INF>2</INF>CuO<INF>4</INF>. X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and double-layer capacitance (C<INF>dl</INF>) outcomes reveal that heteroatom-doped perovskites exhibit more oxygen vacancies and higher electrochemical active surface areas, leading to a significant improvement in the CO<INF>2</INF>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.