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Synthesis, characterization and photocatalytic activity of nanotitania loaded W-MCM-41

机译：纳米二氧化钛负载W-MCM-41的合成，表征和光催化活性

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Nanocrystalline titanium oxide (TiO2) is a promising material as a photocatalyst for photodecomposition of hazardous organic pollutants under illumination, because it is cheap, safe, environmentally benign, and chemically stable. However, the control of particle size and monodispersity of TiO2 is a challenging task. The use of MCM-41, an inorganic template of uniform pore size (2-10 nm), can overcome this difficulty and produce stable nanoparticles of uniform size and shape. In an attempt to extend light absorption of the TiO2-based photocatalyst towards the visible light range and eliminate the rapid recombination of excited electrons/holes during photoreaction, a new photocatalyst (25% TiO2-loaded W-MCM-41) powder was prepared. W-MCM-41, with different ratios of Si to W (Si/W = 25, 50, 75), was synthesized by a hydrothermal method and loaded with 25 wt% TiO2 utilizing a sol-gel method. In order to compare the photocatalytic activity of our sample, titania- loaded plain MCM-41 was also prepared. These materials were characterized by various physiochemical techniques such as UV-visible absorption spectroscopy, x-ray diffraction, nitrogen adsorption-desorption isotherm measurement, Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy. The photocatalytic activity of the prepared samples was evaluated using methyl orange as a model organic compound. It was found that the photodegradation ability of 25% TiO2-loaded W-MCM-41 was highly related to the amount of W atoms present in the sample; the optimum atomic ratio of Si to W was 25. It has been confirmed that the recombination rate of electrons/holes in 25% TiO2/W-MCM-41 declined due to the existence of W atoms in the sample.
机译：纳米晶二氧化钛（TiO2）廉价，安全，对环境无害且化学稳定，是一种有希望的材料，可用于在光照下光解有害有机污染物。但是，控制TiO2的粒径和单分散性是一项艰巨的任务。 MCM-41（孔径均匀（2-10 nm）的无机模板）的使用可以克服这一难题，并生产出粒径和形状均一的稳定纳米颗粒。为了将TiO 2基光催化剂的光吸收范围扩大到可见光范围，并消除光反应过程中激发的电子/空穴的快速复合，制备了一种新的光催化剂（负载了25％TiO 2的W-MCM-41）。通过水热法合成具有不同的Si与W的比例的W-MCM-41（Si / W ＝ 25、50、75），并通过溶胶-凝胶法负载25重量％的TiO 2。为了比较我们样品的光催化活性，还制备了负载二氧化钛的普通MCM-41。这些材料通过各种物理化学技术进行了表征，例如紫外可见吸收光谱，X射线衍射，氮吸附-解吸等温线测量，傅立叶变换红外（FT-IR）光谱和透射电子显微镜。使用甲基橙作为模型有机化合物评估了制备的样品的光催化活性。发现负载25％TiO2的W-MCM-41的光降解能力与样品中存在的W原子数量高度相关; Si与W的最佳原子比为25。已经确认，由于样品中存在W原子，在25％TiO2 / W-MCM-41中电子/空穴的复合率下降。

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