Controllable Active Sites in Cu2–xSe/Cu/NC Nanoparticles for Efficient Electroreduction to C₂₊ Products

Metal nanoparticles make up a special class of nanomaterials with precise crystal structures and compositions that play a crucial role in exploring structure–property relationships. Copper (Cu)-based nanoparticles possess great potential for electrocatalytic carbon dioxide (CO2) reduction to produce long-chain hydrocarbons and multicarbon oxygenated compounds (C2+). Herein, we have designed and synthesized Cu2–xSe/Cu/NC catalysts, whose Cu0–Cu+ species content on the surface can be tuned by the calcination temperature, with a bias current density of 30.44 mA cm–2 at −1.4 V versus RHE and a Faraday efficiency (FE-C2+) of 71.57%. The experimental results show that Cu+ can adsorb intermediates *CO efficiently and reduce the reaction potential barrier to promote C–C bond coupling, providing insights into the design of catalytic materials that direct the reaction pathway toward the C2+ product.