Sio2 Assisted Cu0-Cu+-Nh2 Composite Interfaces for Efficient Co2 Electroreduction to C2+ Products

Electrochemical CO2 reduction reaction (CO2RR) for high value-added multi-carbon products (C2+) production over copper oxide-based catalysts is an important way to realize carbon cycle. However, developing effective reaction interfaces and microenvironments to improve the Faraday efficiency and current density of C2+ remains a major challenge. Herein, we construct Cu0-Cu+-NH2 composite interfaces with the assistance of SiO2. Using Cu2O nanoparticles as a model catalyst, a layer of porous SiO2 is first coated on the surface of the particles, and under CO2RR, part of Cu+ is reduced to Cu0, and part of Cu+ maintains positive valence under the strong interaction of SiO2, forming the interface of Cu0-Cu+. Then, a silane coupling agent containing -NH2 is bonded on the surface of SiO2 which acts as a bridge between copper species and -NH2 to form a Cu catalyst-NH2 group interface. With the help of synergistic effect of the composite interfaces, the optimized Cu2O@SiO2-NH2 catalyst achieves a selectivity of 81.2% for C2+ products at a current density of 292 mA cm-2 at -1.7 V versus reversible hydrogen electrode. In situ Raman and attenuate total reflectance-infrared absorption spectroscopy (ATR-IRAS) spectra show that the interaction between surface -NH2 and CO2 molecules enhances the adsorption and activation process of CO2 and promotes the formation of *CO intermediates. On the Cu0-Cu+ interface, the C-C coupling process between *CO is accelerated, and the two interfaces synergistically promote the generation of C2+ products. This work provides a new idea for the construction of composite interfaces to improve CO2RR to C2+ products.