Doping And Modification Of Photocatalysts Based On Lanthanum And Bismuth And Their Photocatalytic Properties

In the past few decades,photocatalyst has been used exten-sively to deal with energy and environmental problems,such as solar energy conversion and pollutant removal.The catalytic per-formance of many wide band gap?Eg?photocatalysts is limited to UV light radiation,which is only 3-5 percent of solar radiation.To better use the solar light for energy conversion,the development of visible light responsive photocatalysts is highly desirable because visible light contributes about 43 percent to the solar spectrum.Therefore,numerous new photocatalysts with appropriate and smallband gap have been designed and explored to make full use of the solar energy.In particular,the photocatalysts of visible light driven photocatalysts have become one of the hot spots in the field of photocatalytic research.The citric acid complexation method is generally selected as the preparation of the La_xSr_1-xMnO₃?x<1?perovskite catalyst.Template hydrothermal method can make the catalyst surface area increases,the dispersion becomes better.Therefore,X-BiVO₄?X was template?catalysts were prepared by hydrothermal method using different templating agents.The properties of the catalysts were analyzed by means of scanning electron microscopy,X-ray diffraction,X-ray emission,Surface area measuring instrument and Ultraviolet visible diffuse reflectance spectrometer.Lanthanum-based catalysts for the degradation of dyestuff wastewater.Phenol and hexavalent chromium were used as pollutants to simulate the degradation performance of bismuth-based catalysts for industrial wastewater.The main content is as follows.?1?The preparation of La_xSr_1-xMnO₃?x<1?perovskite catalyst became true.The influence factors on photocatalytic activity was taken into account,such as pH of solution,oxidant and so on.The results showed that the performance of the degradation of methyl orange?MO?under acidic condition was outstanding than alkaline condition,and the adsorption of methyl orange?MO?could reach more than 90%under the acidic condition.Meanwhile,La0.4Sr0.6MnO3 catalyst with oxidant shows better photocatalytic activity than that without oxidant.The adsorption properties of La0.4Sr0.6MnO3 catalyst and the kinetics of photo-oxidation of methyl orange?MO?was explored.The results met with the Langmuir model and first order reaction kinetics model.?2?Realizing the controllable preparation of monoclinic crystal crystal phase BiVO₄,meningwhile,it took the twelve amine?DA?,oleic acid?OA?,oleic acid amide?OL?and poly?ethylene oxide?poly?propylene oxide?poly?ethyl oxide?-?P123?as the template agent,such as concentrated nitric acid and sodium hydroxide were used to adjust the pH value.The effects of template and pH on the crystal structure and photocatalytic activity of BiVO₄ were studied.The result found that P123 as the template of BiVO₄ catalyst for catalytic activity is good than other three kinds of catalysts,and the best catalytic activity is when the pH is 1.0.After changing the photocatalytic reaction conditions?dosing quantity,concentration of reaction solution,light conditions?,and found the best dosing quantity is 1 g�L^-1,optimum phenol and Cr⁶⁺ reaction liquid concentration is 0.5 Mill moles per liter.