Study On The Structure Control Of Mesoporous Titania Mixed Crystal Microspheres And The Preparation And Photocatalytic Performance Of The Assembly

Mesoporous TiO₂ materials which are compared with TiO₂ nanoparticles have the advantage of a high specific surface area,a large pore volume,and a narrow pore size distribution.And it is widely used in photocatalysis,dye-sensitized solar cells,self-cleaning,sterilization,and academic and practical fields.However,traditional TiO₂materials have a wide band gap and mainly absorbs ultraviolet light in sunlight?only 5%soalr spectrum?,and hence it has a low utilization of sunlight.In addition,the single crystal phase of TiO₂ photogenerated electron-hole recombination rate is high,and the mixed crystal structure can effectively improve the photo-generated carrier separation efficiency.Therefore,it is still a challenging subject to regulate the mesoporous TiO₂band gap and surface defects to achieve effective absorption of visible-near-infrared light while improving the separation efficiency of photogenerated charge carriers.In this paper,a TiO₂ photocatalytic material with rutile/anatase mixed phase was synthesized by sol-gel-solvent method.In order to improve the utilization of sunlight,a heterojunction composite material is constructed to expand the photoresponse range to the near-infrared region,thereby further improving the separation efficiency of the photo-generated charge carriers,thereby significantly improving the solar photocatalytic performance of the composite.This article is divided into the following three parts:1.Mesoporous TiO₂ mixed crystal microspheres composed of anatase and rutile phases were prepared by using sol-gel-solvent method with tetrahydrofuran as solvent and sol-gel solvothermal method?band gap³.06 eV;specific surface area⁵2.63 m²g?^-1;pore size¹3.8 nm;pore volume⁰.14 cm³g^-1)and the crystal phase structure is effectively regulated,which significantly improves the separation efficiency of photogenerated charge carriers.In order to improve the utilization of sunlight,mesoporous black TiO₂ mixed crystal microspheres were prepared by high temperature surface hydrogenation method,and the photoresponse range was extended to the visible light region,showing excellent visible light catalytic hydrogen production performance(6.4 mmol h^-1 g^-1),1.8 times higher than that of unhydrogenated sample(3.58 mmol h^-1g^-1).2.The mesoporous black TiO₂ mixed crystal microspheres were used as the host.The solvothermal method was used to successfully support the promoter MoS₂ on the surface of mesoporous black TiO₂ mixed crystal microspheres.The heterojunction composite material was controlled and the MoS₂ loading was 25%.The heterojunction composite has the best visible light catalytic hydrogen production performance?86.2?mol h-1 g-1?.MoS₂ can be acted as a co-catalyst replacing precious metal Pt,which greatly reduces the cost of the catalyst and has potential application prospects in the energy field.3.According to the characteristics of energy band position and energy level structure,the two semiconductor light-trapping semiconductor materials were connected by using the promoter MoS₂ as a bridge,and a Cu₂S/MoS₂/mesoporous black TiO₂mixed crystal microsphere tandem heterojunction solar catalyst was constructed.It not only expands the absorption of visible-near-infrared light,but also achieves efficient separation and transfer of photogenerated carriers,which has excellent solar-driven photocatalytic hydrogen production performance(1207.8?mol h^-1 g^-1).At the same time,the research work provides a new research idea for designing high performance tandem heterojunction solar photocatalytic materials.