CdS nanorods embedded in ZnIn2S4 nanosheets to construct n-n heterojunction for ultrahigh photocatalytic H2 and H2O2 production

Abstract

A series of n-n type CdS/ZnIn₂S₄ photocatalysts with type-Ⅱ path were designed by building embedded interface to obtain ultrahigh photocatalytic performance. The CdS nanorods were equably embedded in ZnIn₂S₄ nanosheets to form the one-dimensional/two-dimensional (1D/2D) heterostructure by a two-step synthesis method. Under the illumination of a 420 nm LED lamp, CdS/ZnIn₂S₄ exhibits the optimal photocatalytic hydrogen production rate (33.3 mmol g⁻¹ h⁻¹), which is 4.8 times that of pure ZnIn₂S₄. CdS/ZnIn₂S₄ also displays the best photocatalytic H₂O₂ production rate (1.36 mmol L⁻¹ h⁻¹), which is 2.3 times higher than pure CdS and 3.8 times higher than pure ZnIn₂S₄. Moreover, it exhibits extremely high apparent quantum efficiency (31.71 % at 420 nm) for hydrogen production. This enhanced photocatalytic performance can be attributed to the construction of n-n type heterojunction with built-in electric field action, 1D/2D embedded interface and type-Ⅱ transfer path of photon-generated carriers, which can efficiently improve the light absorption ability, accelerate the spatial separation and transfer of carriers, and provide more active sites for H⁺ reduction to H₂ and H₂O₂.