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

Abstract

• Vs-ZCS/Ni 0.6 Co 0.4 (OH) 2 heterojunction was fabricated for water splitting. • Sulfur vacancies in the photocatalyst provide abundant reaction sites. • The charge separation was significantly enhanced by the S-scheme mechanism. • Synergistic effects render an outstanding H 2 evolution rate of 64.6 mmol·h −1 ·g −1 . 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 Ni x Co 1- x (OH) 2 (0 ≤ x ≤ 1), is successfully fabricated via a facile in-suit hydrothermal method. Among the prepared materials, the Vs-ZCS/5%-Ni 0.6 Co 0.4 (OH) 2 hybrid nanomaterial delivers a superior visible-light hydrogen evolution rate of 64.6 mmol·h −1 ·g −1 in Na 2 S/Na 2 SO 3 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/Ni x Co 1- 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.