Oxygen vacancy-mediated direct solid phase integration of interfacial chemical bond reinforced LaNiO3/RGO/g-C3N4 heterojunction for improving hydrogen production

g-C3N4 has attracted much attention in the field of photocatalysis. However, its high carrier recombination rate has always been an obstacle in practical application. g-C3N4-based heterostructures with an intimate interface contact is considered to be an effective solution to improve the separation and transmission of photogenerated carriers. Herein, an oxygen vacancy-mediated direct solid phase integration strategy is proposed to synthesize a 0D/2D/2D LaNiO3/RGO/g-C3N4 S-scheme heterostructure with interface chemical bonds. The optimized LaNiO3/RGO/g-C3N4 sample showed excellent hydrogen evolution rate of 1375 μmol/g/h, which is far superior to those of pristine g-C3N4 (46 μmol/g/h), LaNiO3/g-C3N4 (143 μmol/g/h), RGO/g-C3N4 (307 μmol/g/h) and mechanically mixed sample LaNiO3-RGO-g-C3N4 (625 μmol/g/h). Also, it is comparable to many g-C3N4-based heterojunction photocatalysts known at present. The improved performance can be attributed to interfacial charge transfer promoted by interfacial chemical bonds served as charge transfer channels and the high redox capacity of S-scheme charge transfer. This work opens up a new avenue for the predictive design of reinforced heterojunction with enhanced photocatalytic performance.