Hydrothermal Synthesis And Photocatalytic Performance Of TiO₂ Nanoparticles And TiO₂/ZnO Nanocomposites

Titanium dioxide ?TiO₂? is an important photocatalyst and shows great research value in the field of air purification and wastewater treatment due to its strong oxidation ability, stable chemical property, low price and so on. Combination TiO₂ nanoparticles with other semiconductor materials can improve its photocatalytic performance.In this paper, TiO₂ nanoparticles and Titanium dioxide/Zinc oxide ?TiO₂/ZnO? nanocomposites have been synthesized by hydrothermal method. The samples were characterized by XRD, SEM, EDS, UV-vis spectra and PL spectroscopy. The photocatalytic performance of samples was studied by aqueous of rhodamine B?RB? as a model contaminant compound.Frist, during synthesis of TiO₂ nanoparticles by hydrothermal method, Orthogonal experimental theory was used to optimizate the reaction parameters. Using the method of range analysis, we found that the pH value of the precursor solution is the influential factor to the photocatalytic performance of TiO₂ nanoparticles based on the degradation of RB. The effect of various experimental parameters on degradation of RB by TiO₂ was also systematically studied, such as initial RB concentration, pH value of solution and dose of catalyst. The results indicated that the degradation of RB decreased with the rise in initial RB concentration. The degradation of RB by TiO₂ could be adjusted with the pH value of solution changing. The fastest degradation could be observed at pH 5. In addition, when the amount of TiO₂ was between 1.0?2.0g/L, the degradation of RB was higher than other samples.Second, based on the optimal process parameters of the TiO₂ nanoparticles, TiO₂/ZnO nanocomposites were prepared. Comparing with TiO₂ samples, the absorbtion peak positions of TiO₂ZnO nanocomposites exhibited marked red shift. In addition, the PL intensity of TiO₂/ZnO nanocomposites are lower than that of TiO₂. It indicates the TiO₂/ZnO have inhibitory effect on the recombination of photo electron-hole pairs. The test on RB solution revealed that photocatalytic efficiency of the composite was the best when Ti:Zn was 100:10. The photocatalytic efficiency of the composite was higher than intrinsic TiO₂ nanoparticles under UV and visible light.Finally, a primary research of metal ion doped TiO₂/ZnO nanocomposites was studied. It was concluded that 1% iron?Fe? doped in can improve the photocatalytic performance. Meanwhile,1% lanthanum?La? doped in can decrease the photocatalytic performance of TiO₂/ZnO nanocomposite.