| With the rapid development of science and technology,environmental pollution caused by industrial production is more and more serious nowadays,threatening human health.The governance of environmental pollution is extremely urgent.The industrial production emits a lot of waste liquid including organic and inorganic wastewater,etc,causing the pollution of water environment.Thus,if human want to have a safe living environment,purification of industrial wastewater must be done.At present,the photocatalytic technology has been widely applied in wastewater treatment field.Research shows that photocatalyst,such as TiO2,ZnO,CdS,ZrO2,and SnO2,is able to degrade the pollutants in the water.In numerous photocatalyst,TiO2 received extensive attention from people and thus become the focus of research scientists on account of its advantages such as environmental protection,non-toxic,stable chemical properties,oxidation ability,low cost advantage,etc.However,on the current market the P25TiO2 photocatalytic materials only a response to ultraviolet light,and the proportion of ultraviolet light in sunlight is only about 5%.So the utilization rate of sun light is low.In addition,after inspired by the light,the light electron and hole produced by it can compound easily,affecting the activity of photocatalytic.To solve these problems,it is necessary to modify the existing TiO2 to change the form and configuration,so as to improve the utilization rate of absorption of light,or to broaden its range of light absorption wavelength to make it possible to be absorbed by the visible light.As a result,it can improve the utilization of the sun light source and light quantum efficiency.At the same time,we can get full play of Ti O2 light catalyst by changing light source.Therefore,exploring the suitable light source is also needed to be studied.Research shows that the doping of metal such as Ag,Au,Pt,etc can accumulate electronic on its surface,restraining light electrons and holes from compounding,so as to improve the activity of photocatalytic.At the same time,they can broaden the absorption scope of TiO2 light and raise the utilization ratio of light energy.As a result,the several kinds of metal has important significance for the research of TiO2 modification.Meanwhile,using the light source that is green,with low energy consumption is benefit for the popularization and application of photocatalytic reaction.The LED light source has excellent characteristics of the above,which has broad application prospects;Xenon light is similar to sun’s rays,which can be used as simulated sunlight to research the activity of the photocatalyst in the sun.Therefore,this article choose LED and Xenon lamp as the source of the light to study the activity of the photocatalyst.This article produced Ni doped TiO2 precursor by sol-gel method,and dope different metal at normal temperature（Ag,Au,Pt）into the precursor above through precipitation,so as to synthesis nanometer TiO2 photocatalytic materials doped by the different metal;Dry and calcine synthetic materials respectively at 60℃,250℃and 250℃.This thesis analyses the phase composition and microstructure of the samples by means of characterization methods such as SEM,BET and XRD etc,and tests photocatalytic degradation effect of methylene blue under the different wavelength of the LED light and xenon light source.Experimental results show that the nano TiO2 sample has the smallest diameter undering the drying temperature of60℃,whch is about 20nm.It has the specific surface area of more than 270 m2/g which has the best photocatalytic performance at 60℃drying under 395nm and 365nm LED light sources.By comparing the photocatalyst effect under different light source,we can see that the light catalyst under xenon light source has the best effect of degradation.Under the single light source,the degradation effect of Pt doped nanometer Ti O2 has best performance,which shows that of Pt performed outstanding in restraining light-generated electrons and holes from compounding,significantly improved the photocatalytic activity of TiO2 catalyst. |
