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

Electroreduction of carbon dioxide (CO 2 ER) 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 C 2 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 C 2 products during CO 2 ER. Herein, cuprous oxide (Cu 2 O) particles are partially encapsulated with silica (SiO 2 ) for significant improvement in FE of C 2 products during CO 2 ER. Compared with pristine Cu 2 O and SiO 2 -fully encapsulated Cu 2 O, the SiO 2 -partially encapsulated Cu 2 O demonstrates an improved FE of C 2 products to ≈70.9 ± 3.1% in an H-type cell. This unique improvement in FE of C 2 can be attributed to the accumulated * CO intermediates and well modulated C–C coupling on a partially SiO 2 -encapsulated Cu-based catalyst. The optimized surface coverage of SiO 2 can not only modulate the electronic structure of Cu for an improved CO 2 ER (including C–C coupling) but also expose enough continuous Cu surface for the coupling of two C-containing intermediates. Therefore, the production of C 2 species can be significantly promoted. This work offers a valuable insight into the designing and development of highly selective CO 2 ER catalysts toward C 2 species.