Studies On Cu-TiO₂ Modified By Organic Small Molecule Or Inorganic Acid To Improve Its Photocatalytic Performance

TiO₂ has attracted much attention in the field of photocatalysis since it was invented due to its excellent photoelectric properties,chemical stability,non-toxic and low price.However,its higher photogenerated carrier recombination rate and lower sunlight utilization rate greatly limit its application range and practical effect.Therefore,how to reduce the recombination rate of photogenerated electrons and holes of titanium dioxide and improve its utilization rate of visible light,and develop a new type of high-efficiency composite titanium dioxide photocatalyst under visible light has been a hot research issue in the field of photocatalysis.In this paper,two types of new titanium dioxide photocatalysts were prepared by combining metal doping with organic small molecule sensitization and inorganic acid surface modification,which effectively improved the performance of titanium dioxide in degrading organic pollutants under visible light.The specific work is as follows:（1）Copper doped TiO₂（Cu-TiO₂）was synthesized by hydrothermal method.With phenol as the target pollutant,the effects of preparation conditions including Cu2+ doping amount,hydrothermal reaction temperature,hydrothermal reaction time and calcination temperature on the photocatalytic properties of Cu-TiO₂ were discussed.（2）Based on Cu-TiO₂,a new nano photocatalyst Cu-TiO₂@HQ was prepared by hydrothermal method with the sensitization of 8-hydroxyquinoline（HQ）,and X-ray diffraction,X-ray photoelectron spectroscopy,UV-vis diffuse reflectance spectra,Fluorescence spectra,and electrochemical impedance spectra are used to characterize the structure and properties of the catalyst Cu-TiO₂@HQ.The photocatalytic degradation of phenol and tetrabromobisphenol A by Cu-TiO₂@HQ under visible light was studied.Furthermore,the possible photocatalytic mechanism of Cu-TiO₂@HQ was proposed by electrochemical,optical characterization and free radical capture experiments.（3）New photocatalysts HA/Cu-TiO₂ modified by inorganic acids（phosphoric acid,hydrofluoric acid,boric acid）were synthesized by impregnation,the effect of inorganic acid modification on the crystal structure,composition and light absorption properties of Cu-TiO₂ was discussed,the degradation of phenol and bisphenol A by HA/Cu-TiO₂ modified with different inorganic acids under visible light was investigated.Based on the electrochemistry,optical characterization and free radical capture experiments,the possible reasons for the influence of acid modification on the activity of Cu-TiO₂ were proposed.