Study On The Syntheses Of Mesoporouse Titanium Dioxide And Organosilicon/Aluminium

Photocatalytic degradation of environmental pollutants using semiconductor photocatalysts has attracted wide attention as a new type of environmental pollution control technology. Mesoporous TiO2 has large surface area, uniform pore size and regular pore distribution, mading it widely used in environmental pollution control area. Dye pollutants can be oxidized into carbon dioxide and water ultimately. However, low efficiency, poor stability and the narrow spectral range of TiO2 limited its application. So it is very important to improve the spectral response range and catalytic efficiency of photocatalysts.Herein, Mesoporous TiO2 with anatase crystalline structure has been synthesized by using Cyathocline Purpurea extract as template without any auxiliary agent. The synthesized mesoporous titania samples were characterized by a combination of various physicochemical techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption/desorption and UV-vis emission spectroscopy (UV-vis). Comparison of photocatalytic activities of the synthesized mesoporous titania samples and Degussa P25 TiO2 were carried out by photodegradation of Rhodamine B, Methyl violet, Methylene blue under solar light and UV light irradiation. The results show that C-TiO2 exhibited significant higher photocatalytic activities than commercial Degussa P25 TiO2 under solar light irradiation. The absorption peak of the dye solution gradually hypsochromic shifted under visible light irradiation due to de-ethylation and degradation of RhB dye. Mesoporous SiO2 synthesized by using Cyathocline Purpurea extract as templateTriethoxysilane and tetraethyl orthosilicate were synthesized using one kettle way in PARR autoclave. The effects of catalyst, reaction temperature, reaction time, pressure on the synthesis were elaborately investigated. The results show that triethoxysilane can not be synthesized in autoclave by one pot way because the conversion of substrate and production yield was too low. However, a high conversion was obtained in tetraethyl orthosilicate synthesis. The optimal reaction conditions were at 220℃, using copper/copper oxide/cuprous oxide composite catalyst and with nitrogen atmosphere. In addition, direct syntheses of silica sol, aluminum isopropoxide and aluminum iodide were also explored.