Stabilizing Cu0/Cu2+ interface by hydroxy-rich amorphous SiO2 for enhanced electrocatalytic CO2 reduction to ethylene

Constructing a stable Cu-0/Cu2+ interface is critical for enhancing the C-C coupling during the process of CO2 electroreduction. However, the high-valence Cu species are unstable under the operating conditions. Herein, polyhedral-shaped CuO is coated with hydroxy-rich SiO2 nanoparticles (m-SiO2/CuO) to stabilize the Cu2+ species, enabling efficient CO2 reduction to the ethylene product. Significantly, the optimal m-SiO2/CuO catalyst exhibits an impressive Faradaic efficiency of 55.5 % and an industrial-level partial current density of 500 mA cm(-2) toward ethylene. Fourier transform infrared spectra and X-ray photoelectron spectra reveal that the strong interfacial interaction between CuO and hydroxy-rich SiO2 is conducive to stabilizing the Cu2+ species. In-situ characterizations reveal that the Cu-0/Cu2+ interface facilitates CO2 activation and the key intermediate *OCCHO, thus promoting the production of ethylene. This work paves the way for developing advanced electro-catalysts of producing ethylene.