Facile preparation of bismuth vanadate-sheet/carbon nitride rod-like interface photocatalyst for efficient degradation of model organic pollutant under direct sunlight irradiation

Abstract

The photocatalytic performance of a semiconducting catalytic system is strongly influenced by charge-carrier separation rate, charge transport properties, surface area, utilization of light energy, and interface bonding. Herein, a series of bismuth vanadate (BiVO4) samples were prepared via hydrothermal method by changing the volume ratios of ethelene glycol and ethanol as a solvent mixture for bismuth precursors. Further, the optimized BiVO4 sheets with hierarchical morphology were used to construct an interface with rod-like g-C3N4 materials, which was confirmed by HRSEM and HRTEM. Due to the formation of an effective interface bonding between BiVO4/g-C3N4, the photoinduced charge carrier's recombination rate was suppressed as confirmed by the PL analysis. The prepared BiVO4/g-C3N4 sample were used to assess the photodegradation efficiency of Rhodamine B (RhB) under direct sunlight irradiation and the photocatalysts degraded ~92.8% of RhB within 2 h. The TOC measurements revealed a 66.4% mineralization efficiency for RhB. In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation. Based on the experimental evidences, a plausible charge transfer mechanism has been proposed. The enhanced photocatalytic activity has been mainly attributed to the inhibition of the recombination rate, enhanced charge carrier transfer efficiency, and high rate of production of reactive species.