High-performance CuO/SiO2 electrocatalysts for highly efficient electrochemical reduction of CO2 to ethylene.

Due to their higher utility value, enhancing the selectivity of multi-carbon products has long been a key objective in the development of carbon dioxide reduction reactions. However, achieving this goal is hindered by numerous reaction pathways, the high energy barrier of C-C coupling reactions, and various side reactions. In this study, we report a method for regulating the pyrolysis process of metal-organic frameworks. By introducing TEOS to control the pyrolysis of CuBTC, we ultimately obtained a high-performance CuO/SiO2 catalyst for the electrochemical reduction of CO2 to ethylene. This catalyst achieved a selectivity of 64.5% for ethylene at a potential of -1.35 V (vs. RHE). Transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) results indicate that the incorporation of TEOS alters the pyrolysis process of CuBTC, induces the formation of oxygen vacancies, and modifies the electronic structure of the Cu sites. In situ Raman spectroscopy and theoretical calculations revealed that the presence of oxygen vacancies enhances the adsorption strength of the *CO intermediate on the catalyst. The accumulation of the *CO intermediate provides the basis for C-C coupling, whilst the reaction energy barrier for the key step of *CO dimerization is optimized, thereby facilitating the conversion of carbon dioxide into multi-carbon products.