Highly Efficient Photocatalytic Hydrogen Production Performance for 2D/0D g-C₃N₄/Zn_0.5Cd_0.5S with g-C₃N₄ as a Transport Medium for Photogenerated Charge Carriers

Abstract

We present synthesis of 2D g-C3N4 nanosheets prepared by high-temperature calcination resulting in a series of 2D/0D g-C3N4/Zn0.5Cd0.5S heterojunctions. The structure, microscopic morphology, photoelectric performance, photocatalytic performance, and the mechanism for enhanced photocatalytic performance were studied through various characterization methods. Results indicate that 0D Zn0.5Cd0.5S nanoparticles (ca. 3~5 nm) were uniformly dispersed on the surface of the g-C3N4 and formed a heterostructure. The photoelectrochemical test shows that an appropriate amount of g-C3N4 modification (10%-C3N4/Zn0.5Cd0.5S) can effectively improve the separation and transfer efficiency of photogenerated carriers. In addition, with the amount of g-C3N4, the hydrogen production performance of the g-C3N4/Zn0.5Cd0.5S samples first increased and then decreased. When the amount of loaded g-C3N4 is 10%, the photocatalytic activity of the 10%-C3N4/Zn0.5Cd0.5S is highest, with hydrogen production of 3.53 mmol·g-1·h−1, 2.8-fold higher than that of pure Zn0.5Cd0.5S (1.26 mmol·g-1·h−1). The enhanced photocatalytic performance could be attributed to introduced g-C3N4 which can supply more reaction sites, and the formation of the heterojunction interface which could effectively improve the separation and migration of photogenerated charge carriers. Therefore, designing a low cost and efficient photocatalys without precious metals will provide a feasible solution to meet the increasing global energy demand.