| Nano titanium oxide as a semiconductor photocatalyst has wide application range. But its low utilization rate of light energy and light raw electron-hole recombination rate is high, for two defects, in this paper, improving the photocatalytic activity of titanium oxide by means of pore and doping. Porous Ti O2 powders were prepared by sol-gel method, and used PEG-1000 as the template agent. It was investigated by orthogonal table. Synthesis Ag-deposited porous Ti O2 powers by reduction Ag+. The Porous Ti O2 and Ag-deposited porous Ti O2 were characterized by BET, XRD, SEM, FTIR and UV-Vis. The optimization conditions of catalysis reaction were studied by degradation rate. The dynamic behaviors of Ag-doped porous Ti O2 for the degradation of methyl orange were researched based on the effects of catalyst content on photocatalysis.The experiment results showed that the optimum conditions of preparation the porous Ti O2 were obtained as follows: the molar ratio of water to butyltitanate and PEG was 10:1:0.25, annealing temperature was 450 ℃, calcining time was 3h. The tests results showed that the specific surface area of porous Ti O2 was 33.9899m2/g, pore volume was 0.1583 m L/g, the average pore diameters was 9.4mm; the XRD chart showed the anatase phase is given priority to, particle size was 16.7 nm; the microstructure of porous titanium oxide is spherical particles testing by SEM. The methyl orange degradation could reach 99.99% under the xenon lamp within 2h using porous Ti O2. The optimal conditions of silver doped porous titanium oxide was mixed silver content was 1.5%, ultraviolet light reduction of time for 7 minutes. The specific surface area of Ag-doped porous Ti O2 was 6.5183m2/g, pore volume was 0.1442 m L/g, and the average pore diameters was 1.0nm; UV-visible spectrum showed that the Ag-doped porous Ti O2 has been red shifted; XRD figure of 1.5% Ag- Ti O2 samples showed the anatase phase, and inhibited the formation of rutile, the size of the samples was about 12.6nm; the particle size was smaller than the porous Ti O2 in the SEM picture. It took 80 min to depredate the methyl orange 93.35% under visible light and 99.99% in UV light using Ag-deposited porous Ti O2. The Silver to improve the structure of the porous titanium oxide, make the light absorption ability not only to enhance and broaden the scope of light absorption, but also raise the utilization ratio of solar energy.The results of photocatalytic degradation of methyl orange by Ag-Ti O2 showed that the optimal amount of photocatalyst is 4g/L, the degradation rate reached 100% by photocatalytic after 80 min under UV or 100 min under visible light and the initial concentration was 10mg/L. In the range of 2-12, photocatalytic activity was better under acidic condition than alkaline condition, and photocatalytic activity was better when the higher p H under alkaline condition, and lower p H under acidic condition. H2O2 had great influence on photocatalytic activity. The paper also analyzed dynamic model of methyl orange degradation under UV condition. It was found that methyl orange was consistent with first order dynamic model basically in the photocatalytic reaction. |
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