Preparation Of Visible Light Photocatalysts Based On Microporous Polymer And Its Photocatalytic Performance

With the rapid growth of the world population and the rapid development of industry,energy crisis and environmental pollution have been attached more and more attention.Photocatalysis is an environment-friendly advanced oxidation technology.However,traditional photocatalysts represented by TiO2 can only respond to ultraviolet light and have a low solar energy conversion efficiency,thus limit the full use of solar energy.Therefore,it is particularly important to look for catalysts that are highly active,highly stable,and especially responsive to visible light.In this paper,three kinds of visible light-responsive photocatalysts were prepared by deposition precipitation-photoreduction method and applied to photodegradation of azo dye RhB.Meanwhile,these catalysts were characterized by various analytical and spectroscopoic thchniques.The main results of the present work were summarized as follows:WO3 was immobilized onto MOFs by microwave-assisted synthesis method.The Ag/AgCl@WO3/MIL-101 visible light catalyst was prepared by compounding Ag/AgCI and WO3/MIL-101 using deposition precipitation-photoreduction method.The catalyst is stable,efficient,and has strong light absorption in the visible region.The experimental results show that the optimal illumination time for the catalyst preparation is 10h,the optimal WO3 loading is 0.3(w)%,and the optimal silver loading is 3.4(w)%.Under this condition,70mL of 20 mg/L RhB solution is almost completely degraded within 90min.In addition,the Ag/AgCl@WO3/MIL-101 catalysts were characterized by the techniques of FT-IR,XRD,XPS,SEM and N2 adsorption-desorption.The hyper-crosslinked polymer SNW-1 was synthesized by hydrothermal method,and the Ag/AgCl@SNW-1 visible light catalyst was prepared by compounding Ag/AgCI and SNW-1 using the deposition precipitation-photoreduction method.The photocatalytic activity was investigated using the degradation of RhB as the evaluation standard in the visible light.The Ag loading and the photoreduction time had an important influence on the photocatalytic performance.The experimental results show that the optimal illumination time is 10h,and the optimal silver loading is 2.6(w)%.Under this condition,70 mL of 20 mg/L RhB is completely degraded within 100 min.The results of SEM and N2 adsorption-desorption characterizations showed that the specific surface area and pore volume of Ag/AgCl@SNW-1 were lower than those of SNW-1 and the dispersion of Ag/AgCl was improved the carrier SNW-1.Ag/AgCl@SNW-1 still exhibits excellent photocatalytic properties.ZnO was prepared by calcining Zeolitic Imidazolate Frameworks ZIF-8 at suitable temperature in air,and Ag/AgCl/ZnO catalyst was prepared by compounding Ag/AgCl and ZnO using deposition precipitation-photoreduction method.The photocatalytic activity was investigated using the degradation of RhB under visible light irradiation.The experimental results show that the optimal illumination time for the preparation of the catalyst is 6h,and the optimum silver loading is 5.3(w)%.Under this condition,70mL of 20 mg/L RhB is completely degraded within 60 min and the catalyst has good reusability.The results of SEM and N2 adsorption-desorption characterizations show that ZnO exhibits different morphologies at different calcination temperatures,and the specific surface area of Ag/AgCl/ZnO catalyst decreases with increasing calcination temperature.The appropriate calcination temperature is 600?.In addition,RhB is degraded by destroying the conjugated structure using Ag/AgCl/ZnO as the catalyst.