Construction of NiS@ZIS@CN photocatalyst with type II and Z-type heterojunctions by self-assembly for efficient photocatalytic hydrogen evolution.

A novel ternary photocatalyst NiS@ZIS@CN with type II and Z-type heterojunctions was synthesized for the first time by hydrothermal and electrostatic self-assembly methods, effectively avoiding the thermal decomposition of CN during the synthesis of the complex. The best ternary catalyst NiS@ZIS@CN is capable of achieving an optimal hydrogen evolution rate of 9750 mmol g h, which is approximately 10.89 times as high as that of CN, indicating that the complex effectively enhanced the photocatalytic properties of the monomer. The coexistence of two types of heterojunctions in the complex effectively enhances photocatalytic performance, in which the monomer ZIS constructs type II scheme with NiS and Z-type scheme with CN, respectively. The two heterojunctions complement each other and jointly promote the rapid electron transfer from NiS and CN to the ZIS surface. In conclusion, the cooperation of the two heterojunctions efficiently facilitates the migration of photogenerated carriers, thus enhancing the photocatalytic hydrogen generation performance of NiS@ZIS@CN.