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.