Graphitic carbon nitride-based composite architectures for photocatalytic hydrogen production: A critical review

The green chemical fuels instantaneously are the key to the global energy crisis along with the environmental challenges. In this regard, there is a continuous rise in the search for avenues for clean and efficient hydrogen energy production. The graphitic carbon nitride (g-C 3 N 4 ) based composite architectures have gained the attraction owing to their exceptional favorable characteristics viz., increased stability, unique bandgap energy, valence band, efficient conductivity, and economic involvement. The present review emphasizes the potential of different g-C 3 N 4 -based composite architectures for green hydrogen production. Taking the fundamentals, background, properties, synthesizing strategies, and optimization into consideration, a tremendous number of studies on g-C 3 N 4 -based composite architectures have been explored. Numerous modification strategies for g-C 3 N 4 -based composites for hydrogen production via photocatalyst are covered. The potential of different composites synthesized via doping g-C 3 N 4 lattice with different metals, non-metals, metal organic frameworks and covalent organic frameworks, MXenes, graphene, carbon dots, perovskite-type oxides, molecular doping, carbon nanotubes, etc., are covered and compared along with the mechanistic insights for the green hydrogen production. The review also briefly discusses regarding the advantages, existing limitations, and future perspectives of g-C 3 N 4 -based composite architectures for hydrogen production.