Nanoscale Cu–Ag Heterostructures for CO₂ Reduction to C₂₊ Products

The electrochemical reduction of CO 2 (CO 2 RR) to value-added chemicals represents a critical strategy for mitigating carbon emissions and promoting energy sustainability. This study focuses on enhancing the CO 2 reduction performance of copper-based catalysts through silver doping, with the specific objective of improving C 2+ product selectivity and suppressing C 1 products. We report the delicate synthesis of three distinct CuAg Janus nanostructures using a coreduction method involving metal precursors for nucleation and growth. Compared to Cu NPs, CuAg Janus 1:0.02 exhibits significantly superior selectivity for both C 2 H 4 (∼50%) and multicarbon products (∼70%) at −1.2 V vs RHE in CO 2 RR. X-ray photoelectron spectroscopy (XPS) analysis reveals that the CuAg Janus nanostructure facilitates an electron transfer process, significantly influencing the catalytic activity and product selectivity of the CO 2 reduction reaction. In-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy spectra indicate that CuAg Janus nanoparticles promote the formation of *CHO and *COCHO, which are key intermediates in the production of C 2 H 4 and enhancement of C–C coupling. This study provides an effective strategy for designing advanced tandem catalysts, paving the way for the widespread application of the CO 2 RR in addressing environmental and energy challenges.