SMAI法制备的Ni—Ag／SiO2双金属催化剂的结构表征

应用溶剂化金属原子浸渍（ＳＭＡＩ）和普通浸渍（ＣＩ）法制备了三种不同摩尔比的ＳｉＯ２负载Ｎｉ－Ａｇ双金属催化剂，ＸＲＤ和磁测定结果表明ＳＭＡＩ催化剂中Ｎｉ和Ａｇ的粒度均小于金属含量相同的ＣＩ催化剂，ＳＭＡＩ催化剂中Ｎｉ和Ａｇ未形成合金，而ＣＩ催化剂中Ｎｉ和Ａｇ形成了合金，ＳＭＡＩ和ＣＩ催化剂都具有超顺磁性，ＸＰＳ测定结果提示，ＳＭＡＩ催化剂中零价，Ｎｉ和Ａｇ的含量高于ＣＩ催化剂，ＳＭＡＩ催化剂中Ｎ

STRUCTURAL CHARACTERIZATION OF SMAI AND CI Ni-Ag/SiO_2 BIMETALLIC CATALYSTS

he solvated metal atom impregnation (SMAI) and conventioal impregnation (CI)methods were used to prepare three different mole ratio bimetallic catalysts supported onSiO2. The results of XRD and magnetic measurements showed that the Ni and Ag particlesizes of SMAI catalysts were smaller than those of CI catalysts with the same metal contents. NiAg alloy was formed in CI catalysts and not formed in SMAI catalysts. BothSMAI and CI catalysts had superparamagnetism. The results of XPS measurementsshowed that the contents of zero-state metallic Ni and Ag of SMAI catalysts were higherthan those of CI catalysts. The Ni concentration on the surface was higher than in the bulkfor SMAI catalysts, i. e. Ni was enriched on the surface, whereas the Ni concentration onthe surface was essentially the same as in the bulk for CI catalysts.