摘要
Raney催化剂由纳米级镍晶粒、未转变的NiAl3和Ni2Al3母相以及包围着它们的界面区组成。X射线衍射和高分辨电子显微观察发现,在脱铝过程中,NiAl3晶粒碎裂为纳米级尺寸,而Ni2Al3相则不出现这现象。NiAl3母相与生成的镍晶体之间有确定的晶体学取向关系,NiAl3的密排面{301}平行于镍的{111}面,两相的密排方向也互相平行。高分辨电子显微像还揭示了原子排列疏松、富含孔洞的界面区结构的存在,脱铝产物镍晶体以及界面区的纳米尺寸特点。
Raney nickel catalyst consists of nanoscale nickel crystallites.untransformed NiAl 3 and Ni 2Al 3 phases and boundary regions around them.X ray diffraction and HREM observation revealed that during leaching grains of NiAl 3 were divided into nanoscale ones,while it did not happen on Ni 2Al 3 phase.The produced nickel crystallites obey a defined orientation relationship with NiAl 3 phase one of the close packed planes {111} of Ni was alwayse parallel to one of the planes {301}of NiAl 3 phase.It seems that the boundary areas present a porous structure and provide passages for the reactants and outcomes.The nanoscale characteristic of the leaching product Ni crystallites and the boundary areas leads to,possibly,hydrogenation catalytic activities for Raney nickel catalysts.
出处
《电子显微学报》
CAS
CSCD
1997年第3期302-306,共5页
Journal of Chinese Electron Microscopy Society
关键词
RANEY
镍催化剂
结构转变
合金
脱铝
取向关系
Raney nikel catalyst structural transformation crystalline orientation relationship