Partial Encapsulation of Cu ₂ O with Silica for Improved Electroreduction of Carbon Dioxide to C ₂ Species

Abstract 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.