2D/2D Transition‐Metal‐Sulfide Self‐Assembly Enables a Huge Tolerance to High Concentration Cr(VI) and a Prominent Photocatalytic Reduction Performance

Abstract

Two-dimensional (2D) transition-metal-sulfides always suffer from poor optical absorption ability, serious photogenerated carrier recombination, and lack of tolerance to high concentration Cr(VI), which limit their wide applications. Herein, 2D MoS 2 nanosheets are in situ grown on 2D 5 % Cu-doped ZnIn 2 S 4 nanosheets to fabricate self-assembly via a two-step solvothermal method. The incorporation of Cu broadens the optical response range of self-assembly and introduces an acceptor trap level that changes the valence band allocation of ZnIn 2 S 4 nanocrystals, which improves the separation and migration of photogenerated electron-hole pairs. As a result, complete photoreduction of Cr(VI) is surprisingly achieved for 2D/2D selfassembly MoS 2 /CuÀ ZnIn 2 S 4 in 4 min under visible light irradiation (λ � 400 nm) without sacrificing any agents. Moreover, this self-assembly is further indicated to have a strikingly huge tolerance to high concentration Cr(VI) (250 mg • L À 1 ), and the photoreduction activity of Cr(VI) is almost not disturbed by high concentration inorganic ions in wastewater. All these merits demonstrate that 2D/2D transition-metal-sulfide self-assembly may find many practical applications in water cleaning and environmental remediation.