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首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Mesoporous SiO2-Modified Nanocrystalline TiO2 with High Anatase Thermal Stability and Large Surface Area as Efficient Photocatalyst
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Mesoporous SiO2-Modified Nanocrystalline TiO2 with High Anatase Thermal Stability and Large Surface Area as Efficient Photocatalyst

机译：具有高锐钛矿型热稳定性和大表面积的介孔SiO2改性纳米晶TiO2作为高效光催化剂

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Mesoporous SiO2-modified nanocrystalline TiO2 photocatalysts have been prepared by sol-hydrothermal processes,followed by post-treatment with appropriate amount of surfactant F127-modified silica sol.The resulting photocatalysts were also characterized by X-ray diffraction,Raman spectroscopy,Brunauer-Emmett-Teller spectroscopy,N2 adsorption-desorption,transmission electron microscopy,FT-IR,X-ray photoelectron spectroscopy,UV-vis diffuse reflectance spectroscopy,steady state surface photovoltage(SS-SPV),and transient state surface photovoltage(TS-SPV)techniques.The photocatalytic activities of the samples were evaluated by degrading rhodamine B solution under simulated solar illumination.The results show that the surface modification with mesoporous SiO2 greatly enhances the thermal stability of the nanocrystalline anatase TiO2,even still being with a main anatase phase after calcination at 900 °C,and the more is the amount of SiO2 used,the more obvious is the ehancement in the thermal stability.This enhancement is attributed to the effective inhibition of the direct contacts and the diffusions among anatase nanocrystals as well as to the retardation of the crystallite growth.Interestingly,the proper amount of mesoporous SiO2-modified nanocrystalline TiO2 samples by thermal treatment at high temperature can exhibit much higher photocatalytic activity than the commercial-available P25 TiO2,which is explained mainly by the high photoinduced charge carrier separation rate resulting from the high anatase crystallinity based on the analyses of SS-SPV and TS-SPV responses and the large surface area related to the small nanocrystallite size and mesoporous SiO2 as well as still possessing a certain amount of surface hydroxyl group.
机译：通过溶胶-水热法制备了介孔SiO2改性的纳米晶TiO2光催化剂，然后用适量的表面活性剂F127改性的硅溶胶进行了后处理。 -塔勒光谱法，N2吸附-脱附，透射电子显微镜，FT-IR，X射线光电子能谱，紫外可见漫反射光谱法，稳态表面光电压（SS-SPV）和瞬态表面光电压（TS-SPV）在模拟日光下降解罗丹明B溶液来评估样品的光催化活性。结果表明，介孔SiO2的表面改性极大地提高了纳米晶锐钛矿型TiO2的热稳定性，即使在锐化后仍保持主要的锐钛矿相在900°C下煅烧，并且SiO2的用量越多，热的提高越明显这种增强归因于有效抑制了锐钛矿型纳米晶之间的直接接触和扩散以及微晶生长的延迟。有趣的是，通过高温热处理适量的介孔SiO2改性纳米晶TiO2样品可以显示出比市售P25 TiO2高得多的光催化活性，这主要是通过对SS-SPV和TS-SPV响应的分析以及较大的表面积分析得出的，这是由于高锐钛矿结晶度导致的高光诱导电荷载流子分离率与小纳米晶体尺寸和介孔SiO2有关，并且仍具有一定数量的表面羟基。

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