Enhancing Electrochemical CO 2 Reduction via A-site Alkaline-Earth Doping in La 2 CuO 4

The electrochemical CO 2 reduction reaction (eCO 2 RR) provides a promising route for converting CO 2 into value-added chemicals and fuels. In this work, we systematically investigate a series of La 1.9 M 0.1 CuO 4 (M = Ca, Sr, Ba) catalysts to elucidate the role of alkaline-earth metal doping in enhancing eCO 2 RR performance. Their phase structures, catalytic activities, and reaction intermediates are characterized. Electrochemical evaluations reveal that among the doped catalysts, Ca-doped La 2 CuO 4 (Ca-LC) delivers the highest selectivity toward C 2+ products, achieving a Faradaic efficiency of 61.2% at −1.4 V (vs. RHE) and exhibiting a C 2+ /C 1 ratio 2.1 times higher than that of undoped La 2 CuO 4 . Electrochemical analysis further indicates that Ca-LC and Sr-LC possess a larger electrochemically active surface area. In-situ infrared (IR) spectroscopy reveals that, compared with undoped La 2 CuO 4 , Ca-LC shows a more pronounced *OCCO peak, indicating more efficient *CO dimerization and thereby promoting C-C coupling and the formation of C 2+ products.