Rational Design and Fabrication of Noble-metal-free NixP Cocatalyst Embedded 3D N-TiO2/g-C3N4 Heterojunctions with Enhanced Photocatalytic Hydrogen Evolution

Developing low-cost and efficient noble-metal-free photocatalytic materials is crucial for the hydrogen production through water splitting. Herein, N-TiO2/g-C3N4 heterostructure loaded with a noble-metal-free NixP cocatalyst was prepared by the combination of ammonia etching and photo-reduction deposition method. The results demonstrated that N-doped TiO2 (N-TiO2) nanosheets were formed and stood upright on the surfaces of g-C3N4 nanosheets, forming a 3D structure. The ternary hybridization of N-TiO2/g-C3N4@NixP hierarchical nanostructure was a promising strategy to achieve highly efficient photocatalytic H-2 evolution, showing an optimized hydrogen evolution rate of 5438 molg(-1)h(-1) using 300 W Xe lamp as irradiation source, which was 7.5 times higher than that of N-TiO2/g-C3N4. The enhanced photocatalytic activity was ascribed to the combined effects of NixP cocatalyst loading and the formation of the intimate nanoheterojunctions between TiO2 nanosheets and g-C3N4 nanosheets, which were favorable for promoting charge transfer. The present work would provide a novel facile preparation and practical application of many other noble-metal-free metal phosphides as a highly efficient cocatalyst for hydrogen production through water splitting.