Zn‐Vacancy Engineered S‐Scheme ZnCdS/ZnS Photocatalyst for Highly Efficient Photocatalytic H2 Evolution.

Vacancy defects engineering is a valid strategy to enhance the separation efficiency of photo‐generated charges. Herein, a zinc vacancy mediated S‐scheme ZnCdS/ZnS composite derived from ZnCdS/MOF‐5 was constructed in‐situ through the sacrificial reagent of Na2S/Na2SO3 aqueous solution in visible‐light irradiation. The MOF‐5 converted to ZnS (ZnS−VZn) with abundant zinc vacancies which were proved by the XPS and PL results. ZnS−VZn has two‐photon absorption performance, which immensely enhanced the visible light absorption capacity for the photocatalysts. The photo‐generated electrons of ZnS−VZn on the Zn‐vacancy defect would regroup with the holes in the valence band (VB) of ZnCdS via ohmic contact which is induced by Zn‐vacancy defects. Therefore, the photoexciton of ZnCdS can be able to separate effectively and eliminate the useless electrons and holes. The ZnCdS/ZnS(20) sample revealed an outstanding photocatalytic hydrogen generation rate of 12.31 mmol h−1g−1 with a turnover number (TON) of 64.61, which is about 82.06 and 21.98 times greater than that of neat ZnS−VZn and ZnCdS. This work gives an insight into the design of the zinc vacancy‐engineered S‐scheme photocatalyst of ZnCdS/ZnS for highly efficient photocatalysis. [ABSTRACT FROM AUTHOR]