CO吸附原位红外光谱结合分子模拟计算研究FCC汽油加氢脱硫催化剂的选择性  

Investigation of Selectivity over HDS Catalysts by in situ IR Spectra of Adsorbed CO and Molecular Simulation Calculation

作　　者：齐和日玛[1,2] 赵晓光[3] 张韫宏[1] 袁蕙[3] 徐广通[3] 

机构地区：[1]北京理工大学化学物理研究所,北京100081 [2]内蒙古医学院药学院,呼和浩特010059 [3]中国石油化工股份有限公司石油化工科学研究院,北京100083

出　　处：《高等学校化学学报》2012年第2期383-388,共6页Chemical Journal of Chinese Universities

基　　金：国家“九七三”计划项目(批准号:2006CB202506);国家科技支撑计划项目(批准号:2007BAE43B01);石油化工催化材料与反应工程国家重点实验室开放课题资助

摘　　要：以脱硫选择性不同的2组催化裂化汽油加氢脱硫催化剂为研究对象,采用CO吸附原位红外光谱表征了2组催化剂的活性相特征,并通过分子模拟计算方法比较了助剂Co加入前后噻吩和1-己烯在催化剂表面的电荷分布、吸附能及其加氢反应的活化能等,探讨了助剂Co的加入对选择性加氢脱硫催化剂脱硫选择性的作用机理.结果表明,加氢脱硫催化剂CoMoS活性相的增加有利于提高催化剂的加氢脱硫/加氢降烯烃(HDS/HYD)选择性.与1-己烯加氢位相比,Co的加入显著提高了噻吩分子加氢位的缺电子性,噻吩在催化剂表面的吸附度增强,显著降低噻吩加氢反应的能垒,从而使噻吩加氢反应更易进行.这也表明CoMoS为高HDS活性、高HDS/HYD选择性的活性相.Two CoMo/Al2O3 catalysts with different supports（Al2O3-A and Al2O3-B） were prepared by pore-filling impregnation.Active phases of the sulfided CoMo/Al2O3 catalysts were identified and analyzed quantitatively by means of in situ FTIR spectrum of adsorbed CO.The charge distribution,adsorption energy and activation energies of hydrotreating reaction of thiophene and 1-hexene on the MoS2 surface before and after adding Co were calculated by molecular simulation,respectively.The results reveal that the increase of CoMoS phase on the catalyst surface improves the HDS/HYD selectivity.Compared with HYD site of 1-hexene,the electron accepting ability of thiophene HDS site can be improved significantly by the adding of Co support,which benefits to improve the adsorptions of thiophene on the surface over catalyst and decrease the activation energy barrier of HDS for thiophene.This fact also points out that the CoMoS phase is the active site of high HDS and HDS/HYD selectivity.

关 键 词：CO吸附 原位红外光谱 量子化学计算 催化裂化汽油 加氢脱硫选择性 

分 类 号：O643.3[理学—物理化学]