(Oxy)nitride heterojunction-strengthened separation of photogenerated carriers in g-C₃N₄ towards enhanced photocatalytic H₂ evolution

The metal-free graphitic carbon nitride (g-C₃N₄) with a series of merits like low cost, favorable stability, and controllable two-dimensional graphite-like structure, has been extensively studied for photocatalytic H₂ evolution. Composite engineering is regarded as one of effective strategies to adjust the kinetics of photogenerated carriers in g-C₃N₄ for elevating its photocatalytic performance. Herein, the composite system of g-C₃N₄ with oxynitride LaTiO₂N was elaborately constructed for improving photocatalytic H₂-evolution performance. With systematical characterizations, the partial cover of g-C₃N₄ nanosheets on LaTiO₂N (LaTiO₂N@g-C₃N₄) was verified and promoted the sufficient contact between g-C₃N₄ and LaTiO₂N, accompanied by the formation of the (oxy)nitride heterojunction. Benefited by the well-matched band structures for g-C₃N₄ and LaTiO₂N, the (oxy)nitride heterojunction strengthened the separation of photogenerated carriers and therefore enhanced the photocatalytic performance of g-C₃N₄. This work gives more insight in composite engineering on g-C₃N₄, and also provides feasible guidelines for designing g-C₃N₄-based photocatalysts towards improving photocatalytic performance.