Co-N₂ Bond Precisely Connects the Conduction Band and Valence Band of g-C₃N₄/CoCo-LDH to Enhance Photocatalytic CO₂ Activity by High-Efficiency S-Scheme

Precise regulation of photogenic electron transfer path plays an important role in improving photocatalytic carbon dioxide reduction efficiency and product selectivity. Herein, under the guidance of density functional theory calculation, the interface chemical bond (Co-N-2 bond) at the atomic level is designed, and g-C3N4/CoCo-layered double hydroxide (LDH) heterostructure is manufactured. CoCo-LDH with water oxidation ability and g-C3N4 were combined to construct S-scheme heterojunction with redox ability. The valence band and conduction band of g-C3N4 and CoCo-LDH are precisely connected by the interfacial Co-N-2 bond, which realizes the high-speed transfer of electron transport. Despite the absence of cocatalyst, the heterojunction exhibits high water oxidation and carbon reduction capacity due to the precise regulation of Co-N-2 bonds. Theoretical calculations and experimental results show that the addition of CoCo-LDH: reduces the oxidation overpotential of water to provide more H protons; regulates the delocalization charge of g-C3N4; and reduces the energy barrier of the CO2 intermediate (*COOH) in the reduction half-reaction. The results show that the selectivity of carbon-based substances in the products was 100%, and the optimal CO yield was 71.39 & mu;mol g(-1) h(-1), which is among the highest values of g-C3N4-based photocatalysts.