Active-center-enriched Ni0.85Se/g-C3N4 S-scheme heterojunction for efficient photocatalytic H2 generation

Photocatalysts with abundant active sites are essential for photocatalytic H2 evolution from water. Herein, Ni0.85Se-deposited g-C3N4 was obtained by a physical solvent evaporation method. The investigation shows that Ni0.85Se with unsaturated active Se atoms can significantly improve the photocatalytic activity of g-C3N4, and the H2 production rate of Ni0.85Se/g-C3N4 can reach 8780.3 μmol g−1 h−1, which is 3.5 and 92.9 times higher than that of Ni0.85+xSe/g-C3N4 (2497.9 μmol g−1 h−1) and pure g-C3N4 (94.5 μmol g−1 h−1), respectively. This improvement can be attributed to the quick charge transfer between Ni0.85Se and g-C3N4 with S-scheme heterojunction feature based on a series of trapping experiments and photoelectrochemical analysis. Moreover, abundant unsaturated Se atoms could provide more H2 evolution active sites. This work sheds light on the construction of heterojunctions with abundant active sites for H2 production.