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分别采用溶胶-凝胶法和共沉淀法制备了TiO2-SiO2复合氧化物,并以此复合氧化物为载体制备了加氢脱硫催化剂。采用氮气恒温吸附脱附、X射线衍射、傅立叶变换红外光谱(FT-IR)和NH3程序升温脱附实验(NH3-TPD)对TiO2-SiO2复合氧化物及其催化剂进行表征,并考察催化剂的加氢脱硫性能。结果表明,TiO2经SiO2复合改性后,其热稳定性和晶相稳定性得到了提高。溶胶-凝胶法与共沉淀法相比,能使Ti物种和Si物种混合得更均匀,从而有利于制得具有较大比表面积和孔容的TiO2-SiO2复合氧化物。Ti含量增加,复合氧化物中Ti的分散度会降低。TiO2-SiO2复合氧化物中以Lewis酸中心为主,共沉淀法制备的复合氧化物比溶胶-凝胶法制备的复合氧化物具有更多的酸性中心。具有较大比表面积和较高酸性的催化剂对模型化合物噻吩和锦西重油催化裂化柴油的加氢脱硫性能较高。
TiO2-SiO2 composite oxides were prepared by sol-gel method and coprecipitation method, respectively, and hydrodesulfurization catalysts were prepared by using the composite oxide as carrier. TiO2-SiO2 composite oxide and its catalyst were characterized by nitrogen adsorption and desorption, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and NH3-TPD. Hydrogen desulfurization performance. The results show that the thermal stability and the phase stability of TiO2 are improved after SiO2 composite modification. Compared with the coprecipitation method, the sol-gel method can make the Ti species and the Si species mix more uniformly, which is beneficial to the preparation of the TiO2-SiO2 composite oxide with larger specific surface area and pore volume. The Ti content increases and the dispersion of Ti in the composite oxide decreases. The Lewis acid centers in the TiO2-SiO2 composite oxide are the main ones. The composite oxide prepared by the coprecipitation method has more acidic sites than the composite oxide prepared by the sol-gel method. The catalysts with larger specific surface area and higher acidity have higher hydrodesulfurization performance for the model compounds thiophene and Jinxi heavy oil FCC diesel.