Promising multicatalytic and adsorption capabilities in V2O5/BiVO4 composite pellets for water-cleaning application

Abstract

The sintered pellets of V2O5/BiVO4 composite with varying V2O5 content (0, 5, 10, 15, and 20 wt%) were fabricated. The effect of V2O5 content on the adsorption, photocatalytic and piezocatalytic activity of V2O5/BiVO4 composite pellets was investigated. The co-existence of orthorhombic V2O5 and monoclinic BiVO4 phases in each composite pellet was confirmed using X-ray diffraction and Raman spectroscopy techniques. The particles of V2O5 with rod or/and plate shaped morphology were visualized under scanning electron microscope along with the irregular shaped BiVO4 grains in all composite pellets. Transmission electron microscopy evidenced the existence of some heterojunctions/interfaces formation between V2O5 and BiVO4 in the composite pellets. X-ray photoelectron spectroscopy reveals the presence of Bi3+/Bi2+ oxidation states of Bi element, V4+/V5+ oxidation states of V element, and O2− oxidation state of O element along with oxygen vacancies in the 20 wt% V2O5 composite pellet. During adsorption experiments, the increase in V2O5 content increased the adsorption of methylene blue (MB) dye. The composite pellet with 20 wt% V2O5 adsorbs ∼76% of MB dye within 36 h under dark, which was only ∼23% in case of 0 wt% V2O5 pellet. During photocatalytic experiments under visible light irradiation for 240 min., the increase in V2O5 content showed increment in percentage degradation of methylene blue (MB) dye. The maximum increment in MB dye degradation was found to be ∼13% in case of composite pellet with 20 wt% V2O5 than that of 0 wt% V2O5 pellet. During piezocatalytic experiments under ultrasonication for 240 min., the increase in V2O5 upto 15 wt% content showed no change in percentage degradation of MB dye. However, the composite pellet with 20 wt% V2O5 showed increment of ∼11% in MB dye degradation than that of 0 wt% V2O5 pellet. Thus, the composite pellet with 20 wt% V2O5 showed enhanced adsorption, photocatalytic and piezocatalytic activity than that of pure BiVO4 pellet, and hence could replace BiVO4 pellet in water-cleaning applications.