In Situ Tracking of Dynamic Reconstruction and Residual Element Effects of Copper Salt-Derived Catalysts in Electrochemical CO ₂ Reduction

Electrochemical CO 2 reduction reaction (CO 2 RR), which enables the directional conversion of CO 2 into high-value-added fuels and chemicals, has emerged as a highly promising cutting-edge approach to mitigating fossil fuel consumption and curbing carbon emissions. Copper (Cu)-based catalysts have been extensively studied in the CO 2 RR, yet the in situ reconstruction mechanism of the catalysts remains an overlooked critical aspect. In this study, we employed diverse metal salt precursors to synthesize CuO catalysts, aiming to investigate the influence of residual elements on the surface reconstruction of catalysts during the CO 2 RR. Furthermore, with the aid of in situ Fourier transform infrared (FTIR) spectroscopy, the key intermediates in the CH 4 formation pathway (*CH 2 O) and the characteristic intermediate in the C 2 H 4 generation pathway (*OCCHO) were successfully captured, thereby elucidating the impact of residual elements on the CO 2 RR pathways. This study provides in-depth insights into catalyst surface reconstruction and offers effective strategies for the design of CO 2 RR catalysts.