关键词: 金属蒸气合成, Cu-Ni双金属催化剂, 磁性质, X射线光电子能谱

Abstract: Ni-Cu/SiO₂catalysts with different compositions were prepared by metal vapor method. XRD, TEM and magnetic measurements showed that Ni-Cu alloy was formed, the composition of the alloy particles were nonuniform and some free Ni and Cu atoms also existed, the metallic particle size depended on the atomic ratios Ni/Cu. As the Cu content increased, the metallic particle size increased and varied between 30-100Å. XPS observations revealed that Ni was in zero, +1, and +2 valence states. Cu mainly existed as metallic Cu and Partly as Cu₂O. The results of XPS also show that the surface compositions of these catalysts were different from those of their bulk. In contrast with the surface enrichment in copper generally observed on Ni -Cu catalysts, the surfaces of these catalyst were enriched in nickel. The results of hydrogenation of furfural showed that the activity of bimetallic catalyst with Ni/Cu molar ratio 1 : 1 was greater than those with Ni/Cu2:1 and 3:1, and those of Ni(or Cu) monometallic catalysts.

Key words: Metal vapor synthesis, Ni-Cu bimetallic catalysts, Magnetic property, XPS (Y,X)