Construction Of Mesoporous Oxide Semiconductor And Study Of Its Catalytic Properties

In this thesis,ordered mesoporous In2O3-CeO2/TiO2 aerogel composite material was fabricated via sol-gel method.The prepared materials were used to degrade the Rhodamine B?Rh B?under visible light irradiation.The 0.2wt%In₂O₃-0.2 wt%CeO₂/TiO₂(In_0.2-Ce_0.2/TiO₂)sample had the highest degradation rate which reached 96.20%.When the degradation time was continuously increased to 110 min,the degradation efficiency of the In_0.2-Ce_0.2/TiO₂ sample was basically remained.The prepared In_0.2-Ce_0.2/TiO₂ sample had the better stability and reproducibility under visible light irradiation.The ordered mesoporous Pt/SiO₂-CeO₂ and Pt/CeO₂ composites were prepared by sol-gel method combined with hard template method.The prepared materials have the high specific surface area and high crystallinity.The individual irregular spherical particles sizes were approximately 20 and 12 nm,respectively.The Pt nanoparticles were reduced on the meso-porous CeO₂ support,and the Pt nanoparticles exhibited good dispersibility and small size.When it was used to reduce 4-nitrophenol,the Pt/CeO2 composite catalyst showed the higher catalytic activity than the Pt/SiO2-CeO2 composite.In addition,the Pt/CeO2 catalyst showed good reusability.The mesoporous Pt/CeO2 and Pt/Fe3O4-CeO2 composites were prepared by the soft template method combined with the chemical liquid deposition method.The prepared materials had the high specific surface area and high crystallinity.After liquid-phase deposition of Fe₃O₄,the prepared Pt/Fe₃O₄-CeO₂ samples exhibitted a loose,lamellar,flower-like structure,and the sheets thickness was about 2 nm.The deposition layer of Fe3O4covered on the inner surface of the Pt/CeO2 matrix pores,which led to the pore size and other pore parameters of the material become smaller.Compared with Pt/CeO₂ composites,Pt/Fe3O4-CeO2 composite catalysts showed the higher catalytic activity.This excellent catalytic performance was derived from the unique structure of Pt/CeO₂ composites and the synergistic effect of Fe3O4 thin films.In addition,Pt/Fe3O4-CeO2 could be easily dispersed without a magnetic field,which also could be rapidly separated from the mixture with the help of a magnet.This excellent magnetic response behavior of the Pt/Fe3O4-CeO2 sample facilitated the rapid and extensive enrichment and separation.The CdS/TiO₂ composites were prepared by sol-gel method and solvothermal method.The TiO2 and CdS in the prepared CdS/TiO2 composites were anatase and hexagonal phases,respectively.The prepared composite material was a gel-like block structure composed of heterogeneous spherical gel particles.The particle size of the composite nanoparticles was about 14 nm,which also has a large specific surface area.The CdS/TiO2 composite exhibitted an absorption band in the visible region,and its absorption intensity increased with the increase of the CdS content.With the increase of the CdS:TiO₂ ratio,the catalytic performance of photocatalytic water-producing hydrogenation of composites was also increased.When the TiO2:CdS ratio is 1:1,the photocatalytic activity of the composite material for hydrogen production was the highest,and the average hydrogen production rate could reach 2167.32?mol/?g·h?.It has the great application prospects in photocatalytic water-producing hydrogenation and new energy field.