Construction of 1T-MoS2 quantum dots-interspersed (Bi1−xFex)VO4 heterostructures for electron transport and photocatalytic properties

Abstract

The present study reports trigonal phase molybdenum disulfide quantum dots (MoS₂/QDs)-decorated (Bi_1−xFe_x)VO₄ composite heterostructures. Initially, (Bi_1−xFe_x)VO₄ heterostructure nanophotocatalysts were synthesized through the hydrothermal method decorated with 1T-MoS₂ via a sonication process. 1T-MoS₂@(Bi_1−xFe_x)VO₄ heterostructures were characterized in detail for phase purity and crystallinity using XRD and Raman spectroscopy. The Raman mode evaluation indicated monoclinic, mixed monoclinic-tetragonal and tetragonal structure development with increasing Fe concentration. For physiochemical properties, SEM, EDX, XPS, PL, EPR, UV-visible and BET techniques were applied. The optical energy band gaps of 1T-MoS₂@(Bi_1−xFe_x)VO₄ heterostructures were calculated using the Tauc plot method. It shows a blue shift initially within a monoclinic structure then a red shift with an increase of Fe concentration. 1T-MoS₂@(Bi₄₀Fe₆₀)VO₄ with 2 wt% of 1T-MoS₂-QDs carrying a mixed phase exhibited higher photocatalytic activity. The enhanced photocatalytic activity is attributed to the higher electron transportation from (Bi_1−xFe_x)VO₄ surface onto 1T-MoS₂ surface, consequently blocking the fast electron–hole recombination within (Bi_1−xFe_x)VO₄. 1T-MoS₂ co-catalyst interaction with (Bi_1−xFe_x)VO₄ enhanced the light absorption in the visible region. The close contact of small 1T-MoS₂-QDs with (Bi_1−xFe_x)VO₄ develops a high degree of crystallinity, with fewer defects showing mesoporous/nanoporous structures within the heterostructures which allows more active sites. Herein, the mechanism involved in the synthesis of heterostructures and optimum conditions for photocatalytic degradation of crystal violet dye are explored and discussed thoroughly.