Modification Of TiO₂ Nanomaterials And Their Photocatalytic Performance For CO₂ Reduction And Vocs Degradation

The energy crisis and environmental pollution caused by excessive consumption of fossil energy have become two major problems facing countries around the world.Photocatalytic technology with semiconductor materials as the core has provided us with an ideal new idea for clean energy development and environmental restoration.Photocatalysis can directly convert solar energy into chemical energy?such as photocatalytic reduction of CO₂?,and can also remove volatile pollutants in the environment.The key to its application is the development of high-performance photocatalytic materials.The unique physical and chemical properties of TiO₂ make it widely used in the field of photocatalysis.However,TiO₂ is a wide band gap semiconductor,which mainly responds to ultraviolet light.It has the disadvantages of low utilization of sunlight and easy recombination of photogenerated electrons and holes.These problems are severely limited with its practical application,which is urgent to break through.Based on this,this paper takes TiO₂ as the research object,modifies it and studies its photocatalytic performance.In addition,the morphology and structure of the sample is characterized and analyzed by a variety of techniques,such as SEM,TEM,XRD,I-t,UV-Vis,BET.The main research contents and results are as follows:?1?Using tetrabutyl titanate as the titanium source,anatase TiO₂ was synthesized by hydrothermal method,and then the In₂S₃/TiO₂ composite photocatalyst was obtained by solvothermal method,performance of photocatalytic reduction of CO₂ was tested.The results show that compared with TiO_2,the photocatalytic activity of In₂S₃/TiO₂composites is significantly improved.When 5%In₂S₃/TiO₂ samples are exposed to simulated sunlight for 1 h,the CH₄ generation rate can reach 16.21?mol g^-1 h^-1.At the same time,a possible photocatalytic reaction mechanism was proposed based on the material's band structure position.?2?CdIn₂S₄/TiO₂?CIS/TiO₂?nanocomposites were prepared by in-situ solvothermal method,and the materials were used in the photocatalytic reduction of CO₂ experiments.The experimental results show that under the action of simulated sunlight,the composites exhibit excellent photocatalytic reduction of CO₂ activity.Among them,3%CIS/TiO₂ as the photocatalyst has the highest CO generation rate,reaching 18.32?mol g^-1 h^-1.In addition,XPS and UV-Vis spectra were used to characterize the band structure,and the photocatalytic reaction mechanism of the composite was discussed.?3?B-TiO₂ was prepared by using TiB₂ as a precursor hydrothermal method,and then urea was used as a nitrogen source,calcined in Ar to obtain a high crystallinity B/N-TiO₂ photocatalyst.The photocatalytic performance of toluene degradation was tested.The test found that the B/N-TiO₂?1:5?photocatalyst had the highest photocatalytic activity,and the toluene degradation rate was 67.1%.