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

Constructing a stable Cu 0 /Cu 2+ interface is critical for enhancing the C-C coupling during the process of CO 2 electroreduction. However, the high-valence Cu species are unstable under the operating conditions. Herein, polyhedral-shaped CuO is coated with hydroxy-rich SiO 2 nanoparticles (m-SiO 2 /CuO) to stabilize the Cu 2+ species, enabling efficient CO 2 reduction to the ethylene product. Significantly, the optimal m-SiO 2 /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 SiO 2 is conducive to stabilizing the Cu 2+ species. In-situ characterizations reveal that the Cu 0 /Cu 2+ interface facilitates CO 2 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.