器外预硫化型MoNiP/γ-Al_2O_3催化剂的二苯并噻吩加氢脱硫活性

Hydrodesulfurization of Dibenzothiophene over ex Situ Presulfided MoNiP/γ-Al_2O_3 Catalyst

制备了两种器外预硫化型MoNiP/γ-Al2O3催化剂,并以二苯并噻吩为模型化合物考察了其加氢脱硫(HDS)活性,选择了传统的器内预硫化催化剂作为参比.采用X射线衍射(XRD)、高分辨透射电镜(HRTEM)和X射线光电子能谱(XPS)等手段对二者在加氢活性相方面的差别进行了研究.结果表明,器外预硫化催化剂的HDS活性(最高达到99%)与器内预硫化催化剂相当,但是其加氢能力相对较弱.XRD与HRTEM等研究表明,器外预硫化催化剂所形成的MoS2片晶的堆垛层数相对较低,而Mo与S元素的XPS分析结果则说明相对器内预硫化催化剂,器外预硫化催化剂中不但Mo的硫化度较低,而且MoS2活性相的含量亦较少,而二者活性相之间的这种差异应是导致两类催化剂加氢活性不同的主要原因.

Two ex situ presulfided MoNiP/γ-Al2O3 catalysts have been prepared, and their hydrodesulfurization performance has been evaluated using dibenzothiophene as the model compound. A conventional in situ presultided MoNiP/γ-Al2O3 catalyst was selected as the competitor. The differences in the hydrogenation active phases of the two types of presulfided catalysts have been studied by X-ray diffraction （XRD）, high-resolution trans-mission electron microscopy （HRTEM）, and X-ray photoelectron spectroscopy （XPS）. The ex situ presulfided catalysts had a similar sulfur removal rate （99 % ） to the in situ presulfided one, but showed a lower hydrogenation activity. Morphology studies using XRD and HRTEM showed that the ex situ presulfided catalysts had a lower stacking number of MoS2 slabs. The XPS results showed that both the sulphidity of Mo and the content of MoS2 active phase ot the ex situ presulfided catalyst were lower than those of the in situ presulfided one. The difference in active phase of the two types of presulfided catalysts led to their different hydrogenation activity.