Preparation And Study Of Titanium Dioxide Nanoparticles Composite Catalyst

Nano-semiconductor photocatalysis, as a promising advanced oxidization technology, has attracted much attention in the scientific research due to its potential application in air clean-up and water purification. Titanium dioxide nanocrystallites have widely studied owing to its safety, low cost, stability and remarkable photoactivity to degrade various organic pollutants. The methods using ions-doped, surface modification and oxide-composite are applied to develop the activity and the stability of TiO2 photocatalyst. Separation and recycle of TiO2 photocatalyst have been realized by many methods.On the basis of preparation of single TiO2 nanoparticles, tungstophosphoric acid composite TiO2 catalyst is prepared. Magnetic TiO2 nanoparticles is also prepared in order to realize the separation and recycle use of TiO2 photocatalyst. The emphasis is the study of the surface topography, structure, composition and catalytic activity of the two catalysts. The major research includes the following aspects:1,TiO2 nanoparticles are prepared by microemulsion and sol-gel methods under low temperature. The sample showed small particle size, good dispersion and had good ultraviolet adsorption. Band-edge of adsorption appeared obviously blue-shift. Quantum effect was displayed.2,Tungstophosphoric acid composite TiO2 catalyst is prepared by sol-gel method. The composite nanoparticles proved to be a salt-like structure. The counter anions (PW12O403-) adsorb around the positively charged TiO2 particle as the balance charge. The tungstophosphate ions keep Keggin structure. In addition, the composite TiO2 nanoparticles showed better photocatalytic activity on phenol degradation. The sample was found to be catalytically efficient for the oxidation of benzaldehyde to benzoic acid using H2O2 as oxidant. Composite TiO2 catalyst modified pyrolytic graphite electrode displayd catalytic activity for nitrite reduction in acidic solutions.3,Magnetic TiO2 nanoparticles with nuclear shell structure are prepared. The surface topography, structure, composition, magnetic property, catalytic activity and other characters are studied. Using magnetism to separate and recycle TiO2 photocatalyst has been attempted.