Study On Catalytic Degradation Performance Of TiO₂ And ZnO-based Heterojunction Catalyst

Now,efficient catalytic conversion and catalytic degradation of carbon dioxide,dye organics and other molecules is an important topic in energy revolution and environmental pollution control.Photocatalysis has shown broad application prospects in the above-mentioned fields due to its unique advantages of energy saving,high efficiency,and environmental protection.However,the low efficiency of a single photovoltaic system has always been the bottleneck in the application of photocatalytic technology.Heterogeneous photocatalysts have been made by integrating different semiconductors to establish heterojunction photocatalysts with the advantages of large reaction driving force,high catalytic reaction conversion rate,and low electron-hole recombination rate in the system,which are the research frontiers in the field of photocatalytic conversion.Analyzing the mechanism of photocatalytic reaction and constructing high-efficiency photocatalyst is the focus of photocatalysis research.This thesis takes TiO2,ZnO and other typical oxide photocatalytic materials as the research object,and explores its application in the field of catalytic organic degradation and the repeatability of catalysts.Based on the photocatalytic reaction mechanism,the optimization design of high-efficiency photocatalysts is discussed.The specific research content is as follows:(1)Quantum dot sensitization is an effective means to establish heterojunctions between semiconductors,which can steadily improve the photocatalytic activity of basic catalytic materials.The TiO2 nanosheet array film prepared by us has a large area of highly active(001)crystal plane exposed,which is suitable for the loading of quantum dots.Based on the nanosheet array,the PbS,CdS dual sensitized TiO2 nanosheet array was modified by quantum dots to obtain a TiO2-based heterojunction photocatalyst.We have a detailed discussion on the microscopic morphology,lattice structure,ultraviolet and visible light absorption and photocatalytic degradation process of hydrogenation catalysts.The results show that the catalyst(CdS(30 min)/PbS(5c)/TiO2)has the best photocatalytic degradation activity for rhodamine B.Under visible light radiation,within 160 min,750 ml at a concentration of 2× 10-5 The mol/L organic solution degrades 98.9%.(2)Co-deposition of a variety of semiconductors can realize the preparation of high-effciency heterojunction catalysis,and magnetic materials play a huge role in improving the recycling of photocatalysts.ZnO is a traditional semiconductor catalyst.In this paper,firework-like ZnO with a larger specific surface area is selected as the basis of the hydrogenation catalyst,and its magnetic spinel material CoFe2O4 is combined to successfully design a magnetic heterojunction photocatalyst CoFe2O4/ZnO.The larger specific surface area provides favorable conditions for the catalytic reaction.During the experiment,the effective heterojunction area was controlled by adjusting the mass ratio of ZnO in the material.The experimental results of the catalytic degradation of organic matter further verify that the CoFe2O4/ZnO we designed has a high catalytic degradation activity,and the excellent reuse characteristics are reflected in the four repeated degradation processes,and the degradation efficiency is stable.