Photocatalysis Of Al/Ga Co-doped ZnO And Its Composite Modification

With the rapid advancement of industrial modernization,the problem of organic pollution in water has become increasingly serious.Since photocatalytic technology can decompose organic pollutants in water only under the conditions of room temperature and sunlight,it is a very promising repair technology to solve the water pollution problem.The key and difficult point of photocatalysis technology is the development of high efficiency photocatalyst,and Zn O semiconductor material is one of the most suitable photocatalyst materials because of its abundant source and low price.However,the wide bandgap Zn O（3.37e V）has a low visible light utilization rate and a high photogenic electron hole recombination rate,so the photocatalytic degradation is not eye-catching.Therefore,in this dissertation,Zn O is modified and optimized from the aspects of constructing heterojunction structure and doping to improve photocatalytic performance and achieve effective degradation of organic matter。The specific research content is as follows:（1）The sol-gel method was used to prepare Zn O nano powders with the same Al doping amount and different Ga doping amount.X-ray diffractometer（XRD）,scanning electron microscope（SEM）,ultraviolet spectrophotometer（Uv-vis）and fluorescence spectrometer（PL）were used to characterize the phase composition,morphology,light absorption,and luminescence of the samples.Xenon lamp was used as the visible light source and methylene blue（MB）was used as the degradation model to investigate the photocatalytic activity of AGZ.The results showed that the co-doping of Al and Ga did not change the hexagonal wurtzite structure of Zn O.The particles sizes and forbidden band width decrease with the increase of Ga doping amount.Among the samples,AG₄Z powder has the best light absorption performance in the visible region.AG₂Z shows the lowest photoelectron-hole pair recombination rate and the highest photocatalytic activity,the MB degradation rate reaches 90%.（2）On the basis of AG₂Z with the best degradation effect,and using g-C₃N₄ at different preparation temperatures as the object,the AGZ/CN composite were synthesized by hydrothermal method.FT-IR,XPS,Uv-vis,PL and electrochemical workstation were used to characterize the phase structure and optical properties of the samples.Xenon lamp was used as the visible light source and methylene blue（MB）was used as the degradation model to investigate the photocatalytic activity of AGZ/CN.The results show that the AGZ/CN560composites are composed of AGZ and g-C₃N₄.Compared with the control group,AGZ/CN560 has the smallest band gap,the highest visible light utilization,the lowest exciton recombination rate,the largest photocurrent intensity and optimal degradation efficiency towards MB.（3）On the basis of AG₂Z with the best degradation effect and g-C₃N₄ with the best preparation temperature（560℃）,AGZ/CN composites with different relative contents were prepared by hydrothermal method.XRD,FT-IR,Uv-vis and PL were used to characterize the phase structure and optical properties of the samples.Xenon lamp was used as the visible light source and methylene blue（MB）was used as the degradation model to investigate the photocatalytic activity of AGZ/CN.The results show that the AGZ/CN composites have good crystallinity.Among the samples,the AGZ/CN15 has the smallest band gap,the highest visible light utilization,the lowest exciton recombination rate and the best MB degradation efficiency.