Construction And Properties Of Nano-ZnO Composite Photocatalyst

In recent years,with the acceleration of science and technology and industrialization,energy scarcity and environmental pollution have seriously affected our daily life,which has attracted wide attention from domestic researchers.China’s energy power is mainly coal,but the mining rate of coal is declining year by year,which can not meet China’s energy demand.In addition,the burning of fossil energy harmful pollutants are also produced,and the discharge of factory wastewater causes immeasurable pollution to soil,water and air,the ecological environment on which we live is greatly threatened.Therefore,solving energy and environmental problems is a major challenge in China.The mechanism of photocatalytic oxidation technology is that after the semiconductor absorbs light,some photogenerated electrons and holes migrate to the material surface to form hydroxyl radical and superoxide radical with strong oxidation,and then oxidize pollutants.Photocatalytic technology has attracted extensive attention from scholars at home and abroad because of its mild reaction conditions,no secondary pollution,low price,high efficiency and stability.The most important link in photocatalytic technology is the selection and preparation of photocatalytic materials.ZnO has become one of the most widely studied photocatalytic materials because of its high quantum efficiency,stability and non-toxic,and has good research value and application prospects.In this paper,nano-ZnO was mainly discussed.Through the modification of nano-ZnO and semiconductor composite,efficient and stable photocatalyst was prepared.The factors affecting the preparation of composite catalysts were investigated,and the photocatalytic degradation of organic wastewater was simulated.The optimal degradation conditions were explored and the stability of the catalyst was tested.Around the above contents,the following aspects were mainly carried out:（1）ZnO was prepared by hydrothermal method,and the microstructure of ZnO was analyzed by XRD and SEM.It was determined that the crystal structure of the synthesized ZnO was hexagonal wurtzite structure,and most of them were rod-like with good uniformity.On the basis of the synthesis of ZnO,ethylene glycol was used as the reducing agent to conduct solvothermal treatment of ZnO,so as to introduce oxygen vacancies on the surface of ZnO.The influence of reaction temperature on the synthesized photocatalyst was explored.The optimal reaction temperature was explored by UV-Vis DRS,EPR and electrochemical tests.Compared with pure ZnO,the change of photocatalytic performance of ZnO with the introduction of oxygen vacancies was studied.The photocatalytic degradation experiment showed that when the reaction temperature was 160°C,the ZnO synthesized by ethylene glycol modification had the largest oxygen vacancy and the best photocatalytic performance.（2）Based on the synthesis of ZnO,Ce O₂ was loaded on the surface of ZnO by a simple solution washing method to construct heterojunction photocatalyst Ce O₂/ZnO,and the introduction of Ce O₂ also introduced oxygen vacancies on the surface of the catalyst.The effects of different Ce O₂ loadings on the photocatalytic degradation activity of ZnO were investigated.The results showed that the catalytic effect of Ce O₂/ZnO composite photocatalyst was significantly improved compared with that of pure ZnO and Ce O₂.With the increase of Ce O₂ loading,the photocatalytic efficiency of the composite catalyst increased first and then decreased.The photocatalytic efficiency of Ce/Zn-2 was the highest,and the degradation efficiency of Rh B under visible light and full-spectrum illumination could reach 47%and 86%,respectively.This indicates that the introduction of appropriate amount of Ce O₂ can significantly improve the catalytic effect of ZnO catalyst.In addition,on the basis of the synthesis of composite materials,the composite materials were vulcanized,and used as photocatalyst for the photocatalytic hydrogen production experiment.The hydrogen production performance of the catalyst was tested,and the hydrogen production performance differences of different vulcanized composite materials were compared.