Direct Evidence of Surface Oxidation of Cobalt Nanoparticles in Alumina-Supported Catalysts for Fischer–Tropsch Synthesis

Abstract

Activity and stability of cobalt nanoparticles supported on mesoporous oxides is of extreme importance for the design of efficient catalysts for low-temperature Fischer–Tropsch synthesis. Catalyst deactivation is a major challenge of this reaction. The identification of mechanisms of catalyst deactivation is indispensable for optimizing the catalyst lifetime and hydrocarbon productivity. Most of the previous reports have addressed the modification of the bulk catalyst structure during Fischer–Tropsch synthesis. The present paper provides the first direct experimental evidence of surface oxidation of supported cobalt metal nanoparticles in the Fischer–Tropsch reaction. In addition to other deactivation phenomena, the uncovered surface oxidation of cobalt nanoparticles is likely to be a major reason for catalyst deactivation at higher reaction temperatures and carbon monoxide conversions.