Construction of MoS2/WO3 S-scheme heterojunction photocatalyst for rapid reduction of Cr(VI) under visible illumination

A series of mesoporous MoS 2 /WO 3 nanocomposites were synthesized with a sol-gel technique utilizing Pluronic F-108 as a template. The synthesized MoS 2 /WO 3 nanocomposites were assessed by photoreduction of Cr(VI) under visible illumination. The TEM measurements indicated that the MoS 2 was incorporated on the surfaces and pores of WO 3 NPs with close contact for constructing a heterojunction MoS 2 /WO 3 nanocomposite. The 9 % MoS 2 /WO 3 nanocomposite exhibited the highest photocatalytic ability, and the Cr(VI) ions were reduced completely to Cr(III) within 45 min. The rate constant of 9 % MoS 2 /WO 3 photocatalyst was enhanced 3.76 times larger than WO 3 NPs. This superior photocatalytic ability of MoS 2 /WO 3 nanocomposites could be ascribed to the fast separation efficiency of photocharge carriers, the mesopore structures, the creation of heterojunction MoS 2 /WO 3 nanocomposites, and wide-spectrum visible light response. Besides, the PL spectrum , Mott-Schottky plot, and I-t curve verified that the photocurrent of MoS 2 /WO 3 was greater than that of WO 3 NPs, implying that integration of MoS 2 facilitated the migration of electrons and retarded the recombination of photocarriers. MoS 2 /WO 3 nanocomposites exhibited quite a stability and photocatalytic ability for Cr(VI) reduction preserved 94 % after five cycles, indicating that the fabricated MoS 2 /WO 3 photocatalyst possessed a potential application to reduce Cr(VI) ions. • Mixed soft template-asisted solvothermal growth of 3∼12 % MoS 2 -coupled WO 3 nanorods. • MoS 2 improved light-induced carrier separation and harvesting at E g of 1.9 eV. • 9 % MoS 2 /WO 3 showed rapid photoreduction of Cr(VI) to Cr(III). • 9 % MoS 2 /WO 3 display five-time reusability with 94 % of its effeciency