Insight into the role of Ni atoms at the interface of g-C3N4/CdS in photocatalytic H2 evolution

[Display omitted] •g-C3N4/Ni/CdS is constructed by insetting highly dispersed Ni atoms between g-C3N4 and CdS.•The resultant g-C3N4/Ni/CdS displays a high H2 evolution rate of 9.5 mmol/g/h.•Ni atoms dispersed on the surface of g-C3N4 contribute to the intimate deposition of CdS.•Ni atoms facilitate the rapid transfer of charge carriers between g-C3N4 and CdS. Highly efficient interface charge carrier transfer and separation is a primary factor in guaranteeing the performance of hetero photocatalysts. Here, we construct a high-performance g-C3N4/CdS heterostructure by insetting highly dispersed Ni atoms between g-C3N4 nanosheets and CdS nanoparticles, and the obtained CNN/Ni500/CdS-2.4 displays the highest H2 evolution rate of 9.5 mmol/g/h without the addition of extra co-catalyst, which is about 4.3 times to that of CNN/CdS heterostructure without Ni atom addition. It is found that the significantly enhanced H2 evolution ability can be ascribed to the dual function of Ni atoms in linking hetero interfaces and facilitating charge transport. The introduced Ni atoms disperse uniformly on the surface of g-C3N4 and thus contributing to the large area uniform and intimately deposition of CdS nanoparticles, which provides sufficient surface-active sites for the photocatalytic reaction. At the same time, due to the good the conductivity, the introduction of Ni atoms dramatically facilitates the rapid transfer of charge carriers between g-C3N4 and CdS and thus accelerating the generation of hydrogen. This work demonstrates the great potential of trace amount of highly dispersed metals on improving the quality of heterojunctions and promoting the photocatalytic ability of heterostructures.