Direct Z-scheme WO3/In2S3 heterostructures for enhanced photocatalytic reduction Cr(VI)

Abstract

The design of efficient and stable photocatalysts for the removal of heavy metals in the environment has become a research hotspot. Here, a composite photocatalyst with three-dimensional In 2 S 3 microspheres supported by WO 3 nanoparticles was synthesized for the photoreduction of Cr(VI) for the first time. The constructed composite catalyst has a direct Z-scheme electron transport mechanism without any precious metals (Au, Pt, and Ag), quantum dots (TiO 2 QDs) or carbon materials (Graphene) as electronic media. Constructing a direct Z-scheme WO 3 /In 2 S 3 photocatalyst can greatly retain the reduction and oxidation reaction sites on the surface of the heterojunction and accelerate the reduction reaction. Under visible light irradiation, it greatly promotes the photocatalytic reduction of Cr(VI), which is 67.7 times and 3.6 times the reduction rates of WO 3 and In 2 S 3 , respectively. The favorable photocatalytic performance of WO 3 /In 2 S 3 should be attributed to the effective interfacial contact between the semiconductors in the Z-scheme system, thereby realizing effective electron transfer and charge separation. In addition, the stability of WO 3 /In 2 S 3 was studied, and a possible mechanism in the photoreduction process of Cr(VI) was proposed. • The 0D/3D WO 3 /In 2 S 3 were synthesized via a facile in-situ solvothermal method. • The close contact between WO 3 and In 2 S 3 realizes effective electron transfer and charge separation. • The Z-scheme electron transport system was developed between WO 3 and In 2 S 3 to enhance photoactivity. • The WO 3 /In 2 S 3 shows superior photocatalytic reduction towards Cr(VI) in 60 min.