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

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.