球状アルミナ担体中でのニッケル微粒子の分布制御
1987 年 8 巻 5 号 p. 372-379
詳細
1987 年 8 巻 5 号 p. 372-379
Control of a radial concentration of nickel metal particles in an alumina sphere was achieved by impregnating the sphere with a solution composed of nickel nitrate dissolved in ethylene glycol, ethyl silicate, and a small amount of nitric acid. The position of the nickel narrow band from the center of the sphere was well controlled merely by the impregnating time. The nickel loading in the catalyst was intentionally varied with the nickel concentration in the impregnating solution.
The external surface of the catalyst prepared was covered with a thin SiO2 film resulted from gelling of ethyl silicate over the alumina sphere. The micro-pores observed in the thin SiO2 films were sharply sized around 20Å.
One of the features of this technique is the formation of macro-molecules consisting of Si-O-Ni-O-Si structure during the preparation of impregnating solution. When the alumina spheres were immersed, these macro-molecules adhere to the external surface of the spheres, followed by the elimination and migration of Ni ions into spheres to form a radial distribution of the fine metal particles.
