Atomic Structure Design for Enhancing Metal‐Support Frontier Orbital Interaction to Achieve Efficient Photocatalytic H₂O₂ Generation

Modified g-C3N4 has been widely applied in various photocatalytic reactions. However, designing efficient atomic structures, breaking through the activity bottleneck and elucidating the precise reaction mechanisms remain the critical challenges in photocatalyst development. This work developed one innovative photocatalyst atomic structure design (AuNPsNi1CN) with Ni single atoms, N vacancies and Au nanoparticles (NPs) at g-C3N4. N vacancies enhancing metal-support frontier orbital interaction between the Ni electron orbitals and the g-C3N4's frontier orbitals, forming a highly active site for four-electron water oxidation reaction (4e- WOR), which significantly enhanced the proton (H⁺) supply capacity. Extensive experiments demonstrated that the introduced Au NPs produce H2O2 via two-electron oxygen reduction reaction (2e- ORR), achieving a yield of 437.53 µM·h-1 in pure water. Theoretical calculations indicate that the Ni single atoms cause a regulation in the highest occupied molecular orbital (HOMO), enhancing the oxidation capability of holes, while the Au NPs optimize O2 adsorption energy and lower the reaction barrier for 2e- ORR. This atomic-scale structure design strategy combining defect engineering, single-atom anchoring, and metal NPs loading, provides a novel approach for developing efficient photocatalytic materials.