以钼酸铵为前驱体、亲水性SiO₂为载体,采用等体积浸渍法制备了负载型MoO_3-x/SiO₂系列催化剂。利用X射线衍射(XRD)、拉曼光谱(Raman)、紫外光谱(UV-Vis)、N₂吸附-脱附、X射线光电子能谱仪(XPS)和氢气程序升温还原(H₂-TPR)等技术手段对催化剂性质进行表征。以乙腈为萃取剂、过氧化氢为氧化剂的氧化脱硫反应中,研究了催化活性与催化剂表面性质的内在规律关系。结果表明,MoO_3-x活性组分的团聚是抑制氧化脱硫活性的主要原因,适宜的焙烧温度有利于获得所需活性位点且分散性高的催化剂,可有效对H₂O₂快速活化,提高DBTs脱硫率。在焙烧温度为350℃、O/S摩尔比为3、反应温度为60℃的最佳脱硫条件下,苯并噻吩(BT)、二苯并噻吩(DBT)和4,6-二甲基二苯并噻吩(4,6-DMDBT)的脱除率分别为77.2%、99.3%、96.4%。该催化体系中DBT的脱除率可达到国家脱硫标准(<10 μg/g)。

A series of supported MoO_3-x/SiO₂ catalysts are prepared via equal volume immersion method by using hydrophilic SiO₂ as supporter and ammonium molybdate as precursor.The prepared catalysts are characterized by mean of N₂ adsorption-desorption,X-ray diffraction,Raman spectroscopy,UV-Vis spectroscopy,X-ray photoelectron spectroscopy and hydrogen temperature-programmed reduction.In an oxidative desulfurization process using acetonitrile as extractant and H₂O₂ as oxidant,the intrinsic rule relationship between the catalytic activity and the surface properties of the catalyst is studied.Study results indicate that the agglomeration of MoO_3-x active is the main reason to inhibit the oxidative desulfurization activity.A suitable calcination temperature is important to obtain the catalysts with desired active sites,high dispersion for the rapid activation of H₂O₂ and an improved desulfurization rate.The removal rates of benzothiophene,dibenzothiophene and 4,6-dimethyldibenzothiophene are 77.2%,99.3% and 96.4%,respectively under the conditions that the calcination temperature is 350^oC,the optimal O/S ratio is 3 and the optimal reaction temperature is 60℃.Advantageously,the present catalytic system can achieve China's national desulfurization standard (<10 ppm) with respect to benzothiophene.

刘红利(1996-),女,硕士研究生,研究方向为工业催化,Liuhongli0433@link.tyut.edu.cn。