Synthesis of Tailored Eggshell Cobalt Catalysts for Fischer–Tropsch Synthesis Using Wet Chemistry Techniques

Abstract

Eggshell cobalt catalysts are used in CO hydrogenation reactions due to their ability to maximize the use of precious cobalt metal. The thickness of the shell can be utilized to control the product yield and distribution. In this article, we describe how the metal support interaction can be exploited to control the thickness and, hence, the product distribution. The catalysts are prepared using precipitation of cobalt nitrate solution (dissolved in ethanol) on silica. The metal deposition rate and location are controlled through optimized nonpolar solvent imbibing, followed by water addition to a Co(NO3)2-ethanol solution and hydrolysis by urea. The eggshell coating thickness (in the absence of restricting solvent) onto silica gel substrate has been determined via theoretical equations and experimentally verified during catalyst preparation through microscopic analysis of catalyst samples. Bulk precursor solution properties such as viscosity and surface tension along with substrate properties such as tort...