Preparation And Photocatalytic Activity Of BiOCl Composite Photocatalyst

Deep eutectic solvent with high solubility, low cost, non-toxic, and environmental friendly as a new type of green solvent, which showed great potential and good application prospect in the field of photocatalyst preparation.Therefore in this research, the photocatalyst BiOCl, the plasmonic photocatalyst Ag@AgCl and the composite photocatalyst Ag@AgCl/BiOCl were successfully synthesized in the presence of deep eutectic solvent of choline chloride-urea mixtures through a facile so lvo thermal process. The physicochemical properties of the as-prepared samples were characterized by means of XRD, SEM, XPS and UV-Vis DRS, respectively. The photocatalytic activity was investigated and the supposed photocatalytic oxidation mechanism was elaborated in preliminary. The main contents were shown as the following:1. With Bi(NO3)3·5H2O as the bismuth source, flower-like BiOCl hierarchical structures were successfully synthesized through a solvothermal process. During the reaction process, the eutectic mixtures of choline chloride-urea acted not only as the solvent and the template, but also as a chlorine source for the fabrication of flower-like BiOCL The reaction results showed that the degradation of RhB was a first-order reaction and the photocatalytic activity was much higher than BiOCl prepared from NaCland TiO2. After the catalyst was used 5 times, the change of degradation rate and the XRD spectrum was not obvious, the catalyst has good stability. The degradation rate of RhB was decreased with increasing the initial concentration of RhB and increased with increasing the catalyst dosage at the time of unsaturated. In addition, the dominating reactive species involved in the photocatalytic degradation of RhB in aqueous solution are photo-generated holes and superoxide radicals.2. With AgN03 as the silver source, the plasmonic photocatalyst Ag@AgCl with near-spherical structures was successfully synthesized through a facile solvothermal process. The results indicated that the eutectic mixtures of choline chloride/urea functioned not only as the solvent and the chlorine source, but also as a reducing reagent for the fabrication of plasmatic photocatalyst Ag@AgCl during the reaction process. In addition, the photocatalytic activity toward degradation of MB in aqueous solution was also investigated. The results showed that the plasmatic photocatalyst Ag@AgCl exhibited enhanced photocatalytic activity for the degradation of MB under visible light illumination. Meanwhile, the plasmonic photocatalyst Ag@AgCl exhibited without obviously decreases in activity and the crystal structure after five cycles. Furthermore, the supposed photocatalytic oxidation mechanism of Ag@AgCl was also elaborated in detail.3. With Bi(NO3)3·5H2O as the bismuth source, AgNO3 as the silver source, the composite photocatalysts Ag@AgCl/BiOCl was successfully synthesized through a one-step process.The results indicated that the composition of Ag@ AgCl can improve the photocatalytic activity of the BiOCl, when Bi:Ag=5:1 the photocatalytic performance of Ag@AgC1/BiOCl is the best, samples showed thecellular structure for accumulation of flowering spherical particles, particle size was about 3μm and it was increased by covered with Ag@AgCL The composition of Ag@AgCl also improved the visible light absorption of samples, maked higher degradation efficiencyfor RhB under visible light, the composite photocatalyst has high utilization rate of repeat and good stability. The degradation rate of RhB was decreased with increasing the initial concentration of RhB, the best dosage was about 0.03 g in the initial concentration of 6 mg/L. In addition, the dominating reactive species are photo-generated holes and superoxide radicals.