Discovery of main group single Sb-N₄active sites for CO₂electroreduction to formate with high efficiency

Main group antimony (Sb) species are promising electrocatalysts that promote the CO2 reduction reaction (CO2RR) to formate, which is an important hydrogen storage material and a key chemical intermediate in many industrial reactions. Herein, we discovered that an Sb single atom (SA) material consisting of Sb-N4 moieties anchored on N-doped carbon (NC) nanosheets (named Sb SA/NC) could serve as a CO2RR catalyst to produce formate with high efficiency. Sb SA/NC exhibited a formate faradaic efficiency of 94.0% at -0.8 V vs. RHE. In situ X-ray absorption fine structure (XAFS) investigations and density functional theory (DFT) calculations demonstrated that the excellent CO2RR activity originated from the positively charged Sbδ+-N4 (0 < δ < 3) active sites. Our results present significant guidelines for the rational design and accurate modulation of main group metal (Sb, In, Sn, Bi, etc.) catalysts for the CO2RR at the atomic scale.