Construction of S-scheme heterojunction consisting of Zn0.5Cd0.5S with sulfur vacancies and Ni Co1-(OH)2 for highly efficient photocatalytic H2 evolution

Efficient spatial charge separation under visible light irradiation plays a vital role in improving the photocatalytic performance of semiconductors. It is a promising approach to construct S-scheme charge transfer mechanism to meet this demand. In this research, a hybrid nanomaterial, which consists of zinc cadmium sulfide (ZCS) with appropriate surface sulfur vacancy (Vs-ZCS) and bimetallic hydroxides NixCo1-x(OH)2 (0 ≤ x ≤ 1), is successfully fabricated via a facile in-suit hydrothermal method. Among the prepared materials, the Vs-ZCS/5%-Ni0.6Co0.4(OH)2 hybrid nanomaterial delivers a superior visible-light hydrogen evolution rate of 64.6 mmol·h−1·g−1 in Na2S/Na2SO3 solution, which is about 11.1 and 3.5 times as much as those of ZCS (5.8 mmol·h−1·g−1) and Vs-ZCS (18.5 mmol·h−1·g−1), respectively. The significantly boosted photocatalytic performance over Vs-ZCS/NixCo1-x(OH)2 hybrids is ascribed to the abundant active sites caused by sulfur vacancy and efficient interfacial charge separation induced by S-scheme charge transfer mechanism. This work highlights the critical role of sulfur defects and bimetallic hydroxides modification in construction of S-scheme system and provides a new strategy for the design of highly efficient photocatalyst.