Preparation And Characterization Of Netlike Nano-TiO₂ And TiO₂ Nano-composties

Nano titanium dioxide (nano-TiO2) is considered as an ideal photocatalyst for the low energy consumption, non-selective degradation, chemical and physical stability, biological nontoxicity, low cost and other unique features. And it has been widely used in air purification, water purification, antibacterial area and other fields. In our study, we have improved the activity and stability of TiO2 photocatalyst by using Ag-doped. The main content is as follows:(1) In this study, netlike nano-TiO2 in macroscopic and granular in microscopic has been successfully prepared via template method, using tetrabutyl titanate (TBOT) as titanium reagent, chloroform (CHCl3) as solvent, polylactic acid (PLA) as template reagent. The effect of the mass ratio of TBOT and PLA was investigated. The optimal react condition is 700℃for 4.5 h with the mass ratio of 1:10. The photocatalytic activities of TiO2 for methyl orange (MO), methylene blue (MB) and methyl red (MR) were excellent, especially for MB. Recycle of TiO2 after photocatalytic degradation was tried.(2) A series of C/TiO2 with different mass ratio of TBOT and PLA by calcining at 700℃for 4.5 h in present of nitrogen. The activities of C/TiO2 composites for photocatalytic degradation of MB were improved with incre asing the mass ratio of TBOT and PLA.(3) Template method systhesis with PLA as template reagent, TBOT as titanium reagent, silver nitrate (AgNO3) as silver reagent, CHCl3 and ethanol as solvent has been introduced to fabricate netlike Ag/TiO2 nanocompsite. By comparing the photocatalytic performances of different molar ratio Ag/TiO2 varied from 1 mol% to 6 mol% with pure TiO2, the optimum mole ratio is 3 mol%.(4) The growth dynamics of anatase and rutile were studied. The apparent activation energies of anatase below 650℃and above 650℃were 68.41 KJ/mol and 262.71 KJ/mol accordingly. And the apparent activation energy of rutile was 105.09 KJ/mol. Furthermore, the photocatalytic degradation kinetics of MO and MB were also discussed. Both of the kinetics accorded with Langmiur-Hinshelwood (L-H). The apparent first-order rate constant and the half-time of photocatalytic degradation of MO were 0.0054 min-1 and 128.36 min while the corresponding parameters of MB were 0.0377 min-1 and 18.39 min.