Recent advances in g-C3N4 nanoarchitectonics for efficient photocatalytic H2O2 evolution

Photocatalytic H 2 O 2 evolution techniques are often regarded as superior to the conventional Riedl-Pfleiderer process, which is associated with high CO 2 emissions and significant energy consumption. Graphitic carbon nitride (g-C 3 N 4 ), a representative visible-light-driven photocatalyst, has been widely employed in constructing semiconductor heterostructures for solar-energy-derived photocatalytic oxidation reactions. In particular, the photocatalytic production of H 2 O 2 using g-C 3 N 4 -based heterostructures has attracted increasing attention because it enables a shift in the H 2 O 2 generation pathway, from the traditional two-step single-electron indirect reduction to a more efficient single-step two-electron direct reduction process. Although several reviews have discussed the use of g-C 3 N 4 nanosheets materials in various photocatalytic applications, including their mechanisms in H 2 O 2 generation, none have focused specifically on the construction of layered g-C 3 N 4 through nanoarchitectonics for photocatalytic H 2 O 2 evolution. This review highlights and updates key aspects of g-C 3 N 4 -based catalysts engineered through heterostructure design for H 2 O 2 production, offering new paradigms for advancing photocatalytic H 2 O oxidation technologies, particularly, the microstructure of g-C 3 N 4 nanosheets, defect engineering strategies, functional molecule or group implantation, metal doping and Schottky junction formation, semiconductor heterostructure construction, and other approaches developed to enhance H 2 O 2 production efficiency. The H 2 O 2 evolution mechanisms associated with the composition, structure, and heterojunction types of g-C 3 N 4 materials, as well as recent progress and future prospects in g-C 3 N 4 -based heterostructures for H 2 O 2 evolution are also discussed.