溶剂化金属原子浸渍法制备高分散载型催化剂 II. Fe,Co,Ni催化剂的分散度和催化性能研究

本文利用一种新的方法-溶剂化金属原子浸渍法制备了Fe/γ-Al_2O_3, Fe/SiO_2, Co/γ-Al_2O_3,Co/SiO_2, Ni/γ-Al_2O_3和Ni/SiO_2六种催化剂。H_2化学吸附, TEM和XRD测定结果表明这些催化剂中Fe, Co, Ni金属颗粒平均直径都小于3.0 nm, 金属分散度均大于50%。作者研究了Fe/γ-Al_2O_3, Co/γ-Al_2O_3和Ni/γ-Al_2O_3三种催化剂在CO+H_2反应中的催化行为, 测定了碳氢产物分布和比催化活性, 表明随着H_2/CO比增大和反应温度升高。较高分子量物种产量减少, 有利于生成甲烷。催化剂的活性大小次序为Fe>Ni>Co。

Preparation of Highly Dispersed Supported Metal Catalyst VIA Solvated Metal Atom Impregnation II. Dispersions and Catalytic Properties of Supported Fe,Co,Ni Catalysts

A new method, Solvated Metal Atom Impregnation (SMAI) technique, was em- ployed to prepare Fe/γ-Al_2O_3, Fe/SiO_2, Co/γ-Al_2O_3, Co/SiO_2, Ni/γ-Al_2O_3 and Ni/SiO_2 catalysts. The results of TEN, XRD and H_2 chemisorption measurements showed that the average particle dimensions of Fe, Co, Ni in these catalysts were <3.0 nm and the dispersions of the metals were >500%. The catalytic behavior of Fe/γ-Al_2O_3, Co/γ-Al_2O_3 and Ni/γ-Al_2O_3 for CO+H_2 reaction was studied. Hydrocarbon product distributions and specifie activities were determined. It showed that, as the H_2/CO ratio and reaction temperature increased, the percentage yield of higher molecular weight molecules decreased and methane formation was favored. The specific activites of these catalysts was in the order as Fe>Ni>Co.