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

The electrochemical reduction of CO2 (CO2RR) to value-added chemicals represents a critical strategy for mitigating carbon emissions and promoting energy sustainability. This study focuses on enhancing the CO2 reduction performance of copper-based catalysts through silver doping, with the specific objective of improving C2+ product selectivity and suppressing C1 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 C2H4 (∼50%) and multicarbon products (∼70%) at −1.2 V vs RHE in CO2RR. 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 CO2 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 C2H4 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 CO2RR in addressing environmental and energy challenges.