Evaluating the photocatalytic efficiency of the BiVO₄/rGO photocatalyst

The present study reported the preparation of BiVO₄ by co-precipitation method. The as-prepared BiVO₄ photocatalyst were deposited on rGO sheets to form BiVO₄/rGO via the hydrothermal method. The crystalline structure, morphological, optical properties, and surface properties of the synthesized pure BiVO₄ compared to BiVO₄/rGO composite were studied using X-ray diffraction (XRD), scanning electronmicroscopy (SEM), photoluminescence (PL) spectrophotoscopy, UV-vis spectrophotometer with an integrating sphere, and N₂ adsorption-desorption isotherm based on BET theory. The photocatalytic activity of the prepared samples were evaluated by the degradation of MB dye in aqueous medium under visible light irradiation. The result showed that the BiVO₄/rGO composite exhibited greater photocatalytic efficiency compared to pure BiVO₄ with the photocatalytic degradation efficiency remains stable up to fifth cycle. The improved activity of the BiVO₄/rGO composite might be attributed to the high surface area available to adsorb more MB molecules, and efficient charge separation of BiVO₄ through π electron on the rGO structure. According to experimental results, the possible photocatalytic mechanism of the BiVO₄/rGO composite were determined and the active species hydroxyl radical were reported. Based on photocatalytic activity inhibition in the presence of both h⁺ (VB) and O₂^•- (CB) scavengers over the BiVO₄ photocatalyst, it can be proposed that the hydroxyl radical generated during the photocatalytic degradation mechanism is mainly responsible by the main active species of h⁺ and O₂^•- at VB and CB positions, respectively.