Novel BiVO4-nanosheet-supported MoS2-nanoflake-heterostructure with synergistic enhanced photocatalytic removal of tetracycline under visible light irradiation

Abstract

This paper describes a simple in-situ hydrothermal technique for the production of BiVO4/MoS2 binary nanocomposites as visible-light-driven catalysts. The as-prepared samples were analyzed by structural, morphological, compositional, optical, surface area, and photocurrent analyses. The lattice fringe spaces at 0.304 nm and 0.612 nm were indexed to the (112) and (002) crystal planes of BiVO4 and MoS2, respectively. Antibacterial photocatalytic capabilities were assessed using tetracycline (TC). Consequently, it was observed that the BiVO4/MoS2 nanocomposite demonstrated improved antibacterial removal ability compared with the pristine samples. The BiVO4/MoS2 nanocomposite exhibited 97.46% removal of TC compared with the pure BiVO4 (43.76%) and MoS2 (35.28%) samples within 90 min. Thus, the photocatalytic performance was observed to follow the given order: BiVO4/MoS2 nanocomposite > BiVO4 > MoS2. The removal of TC after 90 min of irradiation was approximately 97.46%, 96.62%, 95.59%, and 94.45% after the 1st, 2nd, 3rd, and 4th cycles, respectively. Thus, the recycling tests revealed the stability of the photocatalyst, which exhibited a TC removal efficiency of 94.45% without distinct decay, even after the 4th cycle. According to the trapping results, hydroxyl radicals and holes were the key species and demonstrated a greater influence on the photocatalytic performance than superoxide radicals. The increased activity of the BiVO4/MoS2 nanocomposite may be attributed to its large surface area and tunable bandgap, which accelerate the charge-transport characteristics of the photocatalytic system. This insight and synergetic effects can provide a new approach for the development of novel heterostructure photocatalysts.