The Synthesis And Properties Of Series TiO₂-WO₃Composites

Due to excellent catalytic property, gas sensing characteristics, metal oxidesemiconductor composite caused the interest of researchers. In recent yeas,TiO₂-WO₃nanocomposites concerned by research workers for their storage,photocatalytic and gas-sensing properties. Bentonite can be applicated to foodand chemical industry as an important adsorption material. The multifunctionalcomposite is a hot spot to material area. So in this paper, series of TiO₂-WO₃nanocomposites were synthesized, and properties such as gas sensing andadsorption performance of products were investigated.TiO₂-WO₃nanocomposites with variable compositions and TiO₂-WO₃pillaredbentonite were successfully prepared by coprecipitation of TiCl₄andNa₂WO₄·2H₂O followed by a subsequent hydrothermal treatment. Ag-dopedTiO₂-WO₃pillared bentonite compound prepared by dipping. Products werecharacterizated by XRD, SEM, TEM, BET, BJH, ultraviolet-visible spectrumand fluorescence emission spectrum. The effects of parameters including rawmaterials ratio, test methods effect on the morphology and structure of theproduct were examined. Finally we tested the gas sensing properties andadsorption-desorption properties to methylene blue (MB) wastewater of products.The results can be summarized as follows:1. TiO₂-WO₃nanoparticles within50nm synthesized bycoprecipitation-hydrothermal method. The gas sensors from TiO₂-WO₃nanocomposite have shown excellent sensing properties to benzenecompounds and acetone. TiO₂-WO₃nanocomposites (n_Ti:n_W=4:1andn_Ti:n_W=2:1) exhibited good adsorptive property to methylene blue wastewater in three cycle experiments.2. The TiO₂-WO₃composite-pillared calcium/hydrogen bentonites weresuccessfully synthesized by a controlled co-precipitation method combining ahydrothermal method. TiO₂-WO₃composite pillar kept the pore structure ofmodifying bentonites after calcination. The adsorption results indicated thatthe Ti/W calcium bentonites display good adsoptive property than Ti/Whydrogen bentonites. Among them, Ti/W calcium bentonite with assistance ofultrasound shows the optimum removal of MB.3. Ag-doped TiO₂-WO₃pillared calcium bentonites prepared by dipping. The gassensing property of products was investigated. And the result shown thatoptimality doping amounts of calcium bentonite and Ag are3%and3%.