Hexagonal prism-shaped CuO/SnO2 heterostructure for high-performance CO2ER to formate.

A hexagonal prism-shaped CuO/SnO2 heterostructured catalyst with electron-enriched SnO2 active sites was designed and synthesized. The formation of the CuO/SnO2 heterointerface and electron-enriched SnO2 active sites significantly enhanced the catalytic activity and selectivity for HCOO- in electrochemical reduction of carbon dioxide (CO2ER), while the well-defined hexagonal prismatic architecture provided catalytic and morphological stability. Consequently, the catalyst delivered a jHCOO- surpassing that of pure SnO2 by 5 mA cm-2 at -1.2 V vs. RHE and achieved FEHCOO- up to 97% at -0.9 V vs. RHE, retaining FEHCOO- above 80% with negligible current density decay after 36 hours of durability testing.