Melt quenched V2O5/BiVO4 composite: A novel and promising adsorbent and photocatalyst

Abstract

A large number of reports have been published showing negligible adsorption and promising photocatalytic properties of BiVO4 material. In this report, we have used a new and novel method for the fabrication of BiVO4, which can show significant adsorption alongwith the promising photocatalytic properties. V2O5/BiVO4 composite was synthesized using melt-quenching technique followed by the specific heat-treatment at 450 °C for 15 h. The X-ray diffraction (XRD) and Raman spectroscopy techniques confirmed the presence of monoclinic BiVO4 and orthorhombic V2O5 phases in heat-treated sample. The scanning electron microscope (FE-SEM) showed the formation of rod shaped crystals of 50–300 nm sizes and the transmission electron microscope (TEM) showed the heterojunctions formation between V2O5 and BiVO4 in the heat-treated sample. The heat-treated sample adsorb ~ 84% of MB dye from the MB dye solution of 11.75 mg/L initial concentration within 80 min under dark. The adsorption was mainly due to the presence of V2O5 present in it. In addition to this, the 70% of the adsorbed MB dye was recovered during desorption at room-temperature using the heat-treated sample, which is not possible with V2O5 material alone. The formation of heterojunctions between V2O5 and BiVO4 made desorption possible. Moreover, during photocatalysis experiment, the heat-treated sample successfully degraded ~ 88% of MB dye from the MB dye solution of 11.75 mg/L initial concentration within 4 h under ultraviolet (UV) irradiation due to the presence of photocatalytic active crystals of BiVO4 in it. Thus, the adsorption and photocatalytic capabilities of melt-quench V2O5/BiVO4 composite made it a promising material for the removal of organic dye pollutants from the waste water coming from textile industries.