The Study On ZnO Composites Photocatalytic Degradation Of Pollutants In Water And Its Photogenerated Charge Behavior

Photocatalyst driven by solar energy which widely exists in nature,has attracted people's attention in the field of environmental protection owing to its advantages of green and low price.ZnO as a multifunctional inorganic semiconductor material,has large exciton binding energy and electron mobility,have been widely applied to the photoelectric sensor.At the same time,since its facile synthetic method,rich morphology and good thermal stability,ZnO is expected to become the substitute for the traditional photocatalyst TiO₂.However,the disadvantages like serious carrier recombination,the insufficient utilization of sunlight?Eg³.37 eV?and easily to be corroded by light,which limits its further utilization.In recent years,many methods have been used to improve the photocatalytic activity of ZnO,such as ion doping,heterojunction construction,surface modification and so on.In our work,the photocatalysis performance of ZnO is enhanced by alkaline earth element Mg doping,semiconductor CeO₂,ZnSe coupling,noble metal Pt loading.More importantly,in view of the problem that the mechanism of photocatalytic degradation always not clear in most studies,we use surface photovoltaic technology?SPV,TPV,SPC?to study and analyze the photogenerated charge behavior in detail,which provides a new idea for the design of photocatalyst.Our main work is listed as follows:1.Mg-ZnO photocatalyst was synthesized by a simple chemical precipitation method.The reaction of degrading RhB was tested under the gallium iodide UV light,and the photogenerated charge behavior was studied by the work function test and surface photovoltaic technology.The theory of the enhanced photocatalytic activity was put forward.2.Pt/CeO₂/ZnO ternary composites were synthesized by hydrothermal and photoreduction method.The activity of degrading RhB and phenol was tested under the gallium iodide UV light.The strong interaction among Pt,CeO₂ and ZnO was revealed through the active species capture experiments,surface photovoltaic technology as well as solid fluorescence test,possible photocatalytic mechanism was discussed later.3.ZnSe/ZnO microspheres were synthesized by two-step water bath and ion exchange method.The photocatalytic activity of RhB and Cr?VI?was tested under visible light??>420 nm?.The interface photogenerated charge behavior of the samples was studied by electrochemical impedance spectroscopy?EIS?,surface photovoltaic technology and solid-state fluorescence,and the reason of the improvement photocatalytic activity was proposed.