Local Charge Enhancement at Heterojunction Interfaces Caused by High‐Density Dislocations for Improving Photocatalytic H ₂ O ₂ Production

The development of nano‐catalysts with carbon‐encapsulated architectures represents a promising approach for constructing high‐performance catalytic systems. Nevertheless, the reaction kinetics at the surface of the carbon shell and electronic structure evolution at the core–shell interface remain poorly understood, hindering mechanistic insight into the catalytic processes. Herein, the synthesis of layered CoO 2 nanoparticles encapsulated in a graphitic carbon nitride (g‐C 3 N 4 ) framework (g‐C 3 N 4 @CoO 2 ) is reported, which achieves a high photocatalytic H 2 O 2 production rate of 412.7 µmol g −1 h −1 . Detailed structural analysis confirms the exceptional stability of the g‐C 3 N 4 @CoO 2 . Photocatalytic tests under diverse conditions, combined with in situ evidence, establish that H 2 O 2 generation occurs via the two‐electron oxygen reduction reaction (2e − ORR). Furthermore, first‐principles calculations indicate that lattice mismatch, resulting from a high density of stacking faults in the layered material, facilitates local charge accumulation and induces significant electronic restructuring within the g‐C 3 N 4 shell, which boosts the adsorption and activation capabilities of g‐C 3 N 4 @CoO 2 toward reactant species. The work offers a viable design strategy for carbon–nitrogen encapsulated layered metal oxide nanomaterials aimed at efficient photocatalytic H 2 O 2 production, while providing new insights into interfacial effects within composite catalysts.