介孔TiO2晶须-γ-Al2O3复合载体催化剂的制备及其对二苯并噻吩的加氢脱硫性能

以介孔TiO2晶须作为钛源，采用溶胶-凝胶法制备了介孔TiO2晶须与γ-Al2O3复合载体(TiO2-Al2O3)，在此基础上，通过等体积浸渍法制备了不同MoO3负载量的MoO3/ TiO2-Al2O3催化剂，采用N2吸附-脱附(BET)、X射线衍射(XRD)、拉曼(Raman)、H2程序升温还原(H2-TPR)、场发射扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)等表征技术对催化剂结构进行剖析，并考察了其对二苯并噻吩(DBT)的加氢脱硫性能。XRD和Raman等结果显示，当MoO3负载质量分数低于20%时，MoO3能够在TiO2-Al2O3复合载体上分散良好，当MoO3负载质量分数超过20%时，复合载体催化剂上出现晶态的MoO3物种；TPR结果显示，出现晶态的MoO3会增加其还原温度，不利于形成活性相；所有催化剂拥有良好的介孔结构，比表面积均大于200 m2/g。DBT的加氢脱硫结果显示，MoO3/ TiO2-Al2O3复合载体催化剂的MoO3负载质量分数为20%时具有最佳催化性能，DBT转化率达到了56%，优于相同条件纯γ-Al2O3为载体的催化剂(49%)。

Preparation of Mesoporous TiO2 Whisker-γ-Al2O3 Composite Supported Catalyst and Its Catalytic Performance in Dibenzothiophene Hydrodesulfurization

Using mesoporous TiO2 whiskers as precursor, mesoporous TiO2 whiskers andγ-Al2O3 composite support (TiO2-Al2O3) were prepared by sol-gel method, and MoO3/ TiO2-Al2O3 catalysts with different MoO3 loadings were prepared by equal volume impregnation method. The catalysts were analyzed using N2 adsorption-desorption (BET), X-ray diffraction (XRD), Raman, H2-programmedtemperature reduction (H2-TPR), Field emission scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and other characterization techniques, and the catalytic performance in the hydrodesulfurization of dibenzothiophene (DBT) was investigated. The results of XRD and Raman analysis show that MoO3 is well dispersed on the mesoporous TiO2 whisker/γ-Al2O3 composite when the MoO3 loading mass fraction is less than 20%. While the composite supported catalyst crystalline MoO3 species are located in the surface when the loading mass fraction of MoO3 exceeds 20%. TPR results show that the presence of crystalline MoO3 increases reduction temperature, which inhibits the formation of active phase. All catalysts have good mesoporous structures, with specific surface area higher than 200 m2/g. The result of hydrodesulfurization of dibenzothiophene indicates that the mesoporous TiO2 whiskerγ-Al2O3 composite support catalyst displays the highest catalytic performance when the mass fraction of MoO3 is 20%, with DBT conversion reaching 56%, higher than that of pure γ-Al2O3 supported catalyst (49%) under the same reaction conditions.