Ternary CuS@Ag/BiVO4 composite for enhanced photo-catalytic and sono-photocatalytic performance under visible light

Well-designed Z-Scheme CuS@Ag/BiVO4 photocatalyst was fabricated through a multi-step synthesis. The structure was investigated by X-Ray photolectron spectroscopy, X-Ray diffractometer, Valance-band X-Ray photoelectron spectroscopy, scanning electron microscopy, Uv-Vis DRS, and photoluminescence analysis. The activities of the samples were tested for photocatalytic oxidation of Bisphenol - A (BPA) under visible light irradiation. The photo-catalytic efficiencies of CuS@BiVO4 and CuS@Ag/BiVO4 samples were explained by conventional heterojunction and Z-scheme mechanisms, respectively. Optimum degradation of BPA as 77.1% was achieved over CuS@Ag/BiVO4 photocatalyst at the end of 3 h. In the oxidation runs performed with persulfate and hydrogen peroxide, complete degradation of BPA was achieved. The radical scavenger experiment indicated that O-2(-center dot) and h(+) play a dominated role during the photocatalysis of BPA. In the sono-photocatalysis, 850 kHz ultrasonic reactor was observed to be more effective than that of low frequency for consumption of electrical energy to degrade BPA. Reusability tests were performed with three successive runs to determine the stability of the catalyst. Toxicity result showed that the treated BPA solution was 66.3% less toxic than that of untreated BPA solution.