物理化学学报 >> 1994, Vol. 10 >> Issue (06): 543-548.doi: 10.3866/PKU.WHXB19940612

研究论文 上一篇    下一篇

钼镍负载催化剂表面组份及其活性的研究

徐斌, 朱崇业, 李全芝   

  1. 复旦大学化学系,上海 200433
  • 收稿日期:1992-11-13 修回日期:1993-07-20 发布日期:1994-06-15
  • 通讯作者: 李全芝

Surface Species of Molybdenum-Nickel Loaded Catalysts and Their Catalytic Activity

Xu Bin, Zhu Chong-Ye, Li Quan-Zhi   

  1. Department of Chemistry, Fudan University, Shanghai 200433
  • Received:1992-11-13 Revised:1993-07-20 Published:1994-06-15
  • Contact: Li Quan-Zhi

摘要:

利用X光光电子能谱(XPS),激光拉曼光谱(LRS)和程序升温还原(TRP)等技术,研究了高载钼量的负载钼镍催化剂的表面组份形式.结果表明,催化剂在氧化态、还原态、硫化态时表面的主要组份分别以类似NiMoO_4结构的NiMo_xO_y多种价态钼酸盐及金属镍,氧硫钼镍及硫化钼形式存在.三种化学态的加氢脱硫活性顺序为硫化态,还原态>>氧化态.还原态表面检测到金属镍,据此提出了金属镍所产生的氢溢流效应是还原态活性明显增加的一个原因.文中由硫化态、还原态表面组份与反应活性之间的关联结果支持了Kwart提出的多点催化反应机理.

关键词: 高载钼量负载钼镍催化剂, 表面组份形式, 不同化学态, 加氢脱硫活性

Abstract:

Forms of surface species in molybdenum-nichel catalyst with high molybdenum loading have been studied by using the techniques of X-ray photoelectron spectroscopy, Laser Raman spectroscopy and temperature programmed reduction. The results indicate that the main species on surfaces of oxidic, reduced, sulfided catalysts are NiMo_xO_y whose structure is analogous to NiMoO_4, molybdates of different valence and metal nichel, molybdenum nickel oxysulfide and molybdenum sulfide respectively. The hydrodesulfurization activity sequence of the above three chemical states is: sulfided form, reduced form>>oxidic form and it is positively related to low temperature oxygen capacity. Metal nickel has been observed on the surface of reduced form. From this, it is proposed that spillover of hydrogen atoms created on metal nickel is one reason for the distinct increase of HDS activity in reduced catalyst. Surface species forms in sulfided, reduced states and HDS activities have been related. The results support the side-on catalytic mechanism proposed by H. Kwart.

Key words: Molybdenum-nickel binary catalyst with high Mo-loading, Surface species form, Various chemical states, HDS activity