Hexagonal prism-shaped CuO/SnO ₂ heterostructure for high-performance CO ₂ ER 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 <i>j</i>_HCOO^- surpassing that of pure SnO₂ by 5 mA cm^-2 at -1.2 V <i>vs.</i> RHE and achieved FE_HCOO^- up to 97% at -0.9 V <i>vs.</i> RHE, retaining FE_HCOO^- above 80% with negligible current density decay after 36 hours of durability testing.