Interfacial TiN bonding of a g-C3N4/TiH1.92 type-II heterojunction photocatalyst significantly enhanced photocatalytic hydrogen evolution from water splitting

Abstract

Graphitic carbon nitride (g-C₃N₄), an excellent metal-free photocatalyst, is a promising candidate for overall water splitting under visible light illumination. However, some drawbacks of g-C₃N₄, such as poor separation and transfer efficiency of photogenerated charge carriers, restrain its photocatalytic applications. Efficient photocatalytic water splitting could be achieved by combining g-C₃N₄ with well suited divergent semiconductors to form a type-II heterojunction system. Herein, we fabricate a highly efficient type-II heterojunction system based on exfoliated titanium hydride (TiH_1.92) nanoparticles (NPs) and g-C₃N₄ nanosheets for photocatalytic water splitting. Through TiN bonding at the interface between g-C₃N₄ and TiH_1.92 NPs, g-C₃N₄ nanosheets can be coupled with TiH_1.92 NPs. Owing to their specific type-II heterostructures, strong interfacial interaction and band alignment, an efficient photocatalytic hydrogen evolution rate of 75.55 μmol h⁻¹ is obtained, which is 4.29-fold higher than that of bare g-C₃N₄. The developed g-C₃N₄/TiH_1.92 type-II heterostructures exhibit a quantum efficiency of 6.78% at λ = 420 nm. In general, this study further provides a creative route to design and develop other novel type-II heterostructured photocatalysts for efficient H₂ evolution under visible light illumination.