Interlayer Spacing Regulation by Single‐Atom Indium^δ+–N₄ on Carbon Nitride for Boosting CO₂/CO Photo‐Conversion

Abstract Simultaneous optimization on bulk photogenerated‐carrier separation and surface atomic arrangement of catalyst is crucial for reactivity of CO 2 photo‐reduction. Rare studies capture the detail that, better than in‐plane regulation, interlayer‐spacing regulation may significantly influence the carrier transport of the bulk‐catalyst thereby affecting its CO 2 photo‐reduction in g ‐C 3 N 4 . Herein, through a single atom‐assisted thermal‐polymerization process, single‐atom In‐bonded N‐atom (In δ + –N 4 ) in the (002) crystal planes of g ‐C 3 N 4 is originally constructed. This In δ + –N 4 reduces the (002) interplanar spacing of g ‐C 3 N 4 by electrostatic adsorption, which significantly enhances the separation of bulk carriers and greatly promotes the reactivity of CO 2 photoreduction. The CO 2 photo‐conversion performance of this resulted single‐atom In modified g ‐C 3 N 4 is significantly superior to other single atom loaded carbon nitride catalysts. Moreover, the In δ + –N 4 enhances the CO 2 adsorption on g ‐C 3 N 4 , reduces the *COOH formation energy, and optimizes the reaction path. It achieves a remarkable 398.87 µmol g −1 h −1 yield rate, 0.21% apparent quantum efficiency, and nearly 100% selectivity for CO without any cocatalyst or sacrificial agent. Through d (002) modulation of carbon nitride by single In atom, this study provides a ground‐breaking insight for reactivity enhancement from a double‐gain view of bulk structural control and surface atomic arrangement for CO 2 ‐reduction photocatalysts.