Interface-Engineered C4N/MgAl-LDH Heterostructure for High-Performance Photocatalytic H2O2 Production.

Photocatalytic production of hydrogen peroxide (H2O2) from water and air offers a highly promising and sustainable strategy. However, the slow kinetics of water oxidation severely restricts the oxygen reduction half-reaction due to insufficient proton supply, leading to low efficiency of many H2O2 photocatalysts. Herein, we constructed an interface-engineered C4N/MgAl-LDH heterostructure via a straightforward in situ electrostatic self-assembly method. The resulting hybrid photocatalyst exhibits a remarkable H2O2 yield rate of 2.38 mmol g-1 h-1 without cocatalysts and sacrificial agents, along with exceptional stability (≥20 cycles). Its performance significantly surpasses those of bare MgAl-LDH, C4N, and their physically mixed counterpart. The zeta potential analysis confirms the formation of an intimately contacted interface with strong electronic coupling, enabling rapid charge transfer and prominent photocatalytic performances. Isotope tracing experiments employing H2 18O and 18O2 provide clear evidence for dual pathways of H2O2 formation involving both water and molecular oxygen. The incorporation of C4N not only extends visible-light absorption but also promotes the adsorption and activation of key reactants and intermediates. The synthetic approach developed here is simple, cost-effective, and broadly applicable, offering a feasible route for designing advanced photocatalysts for high-efficiency H2O2 production.