Construction of 1T-MoS2quantum dots-interspersed (Bi1-xFex)VO4heterostructures for electron transport and photocatalytic properties

Abstract

The present study reports trigonal phase molybdenum disulfide quantum dots (MoS2/QDs)-decorated (Bi1-xFex)VO4composite heterostructures. Initially, (Bi1-xFex)VO4heterostructure nanophotocatalysts were synthesized through the hydrothermal method decorated with 1T-MoS2viaa sonication process. 1T-MoS2@(Bi1-xFex)VO4heterostructures 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@(Bi1-xFex)VO4heterostructures 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)VO4with 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 (Bi1-xFex)VO4surface onto 1T-MoS2surface, consequently blocking the fast electron-hole recombination within (Bi1-xFex)VO4. 1T-MoS2co-catalyst interaction with (Bi1-xFex)VO4enhanced the light absorption in the visible region. The close contact of small 1T-MoS2-QDs with (Bi1-xFex)VO4develops 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.