Carbon dots modified metallated graphdiyne with enhanced electron transfer and O₂ adsorption capacity for efficient H₂O₂ photoproduction

Hydrogen peroxide (H₂O₂), a promising liquid fuel and environmentally friendly oxidant, can be produced efficiently through photocatalysis, one of the most green and effective methods. Herein, we demonstrate the use of carbon dots (CDs) modified nickel (II) graphdiyne (CDs/Ni-GDY) as a photocatalyst to achieve efficient production of H₂O₂ under visible light irradiation without sacrificial agents. The optimum CDs/Ni-GDY photocatalyst exhibits high efficiency for photocatalytic H₂O₂ production, with a production rate of 1755.18 μmol·h⁻¹·g⁻¹ under visible-light irradiation (λ ≥ 420 nm) in pure water, through simultaneously occurring two-electron oxygen reduction reaction and four-electron water oxidation reaction. In this system, the nickel atoms serve as the active sites, while CDs enhance light absorption and O₂ adsorption and increase the interfacial electron transfer process. This work elucidates the structure–activity relationship between the active sites and the promoter of CDs, achieving an improvement in their efficient catalytic performance and providing a new perspective for photocatalytic material design.