Partial Encapsulation of Cu2O with Silica for Improved Electroreduction of Carbon Dioxide to C2 Species.

Electroreduction of carbon dioxide (CO2ER) has emerged as a promising strategy for converting greenhouse gas carbon dioxide into value-added carbon-based products under mild conditions. Among the diverse products, the C2 compounds, including ethylene and ethanol, are particularly attractive due to their high commercial value and widespread industrial applications. Therefore, it is highly promising to improve the Faradaic efficiency (FE) of C2 products during CO2ER. Herein, cuprous oxide (Cu2O) particles are partially encapsulated with silica (SiO2) for significant improvement in FE of C2 products during CO2ER. Compared with pristine Cu2O and SiO2-fully encapsulated Cu2O, the SiO2-partially encapsulated Cu2O demonstrates an improved FE of C2 products to ≈70.9 ± 3.1% in an H-type cell. This unique improvement in FE of C2 can be attributed to the accumulated *CO intermediates and well modulated C-C coupling on a partially SiO2-encapsulated Cu-based catalyst. The optimized surface coverage of SiO2 can not only modulate the electronic structure of Cu for an improved CO2ER (including C-C coupling) but also expose enough continuous Cu surface for the coupling of two C-containing intermediates. Therefore, the production of C2 species can be significantly promoted. This work offers a valuable insight into the designing and development of highly selective CO2ER catalysts toward C2 species.