Asymmetric-Coordinated Indium Single Atoms for Highly Selective Photocatalytic CO₂ Reduction

Photocatalytic CO₂ reduction involves multiple proton-coupled and multi-electron transfers, leading to a plethora of reaction pathways and consequently unpredictable products. The unique electronic structure and unsaturated coordination environment of single-atom photocatalysts can influence the reaction pathways of CO₂ photoreduction, enhancing the yield of a target product. Herein, we rationally design the In single-atom photocatalyst (In-NTO) containing isolated In^δ+–N₃O₂ atomic interface sites for highly efficient and selective CO₂-to-CO photoreduction. This distinctive atomic configuration not only reduces the overall activation energy barrier but also transforms the key *CO desorption step from an endoergic to an exoergic one, thereby altering the reaction pathway to selectively produce CO rather than CH₄. Consequently, the 0.25 wt% In-NTO exhibits high selectivity (95.9%) for photocatalytic CO₂-to-CO conversion, with a rate of 6.34 µmol g⁻¹ h⁻¹. This work offers a novel strategy for modulating the reactivity and product selectivity of photocatalytic CO₂ reduction toward desired products by constructing single-atom sites with heteroatomic coordination.