EXAFS study in situ of the reducibility of a silica-supported cobalt Fischer-Tropsch catalyst

The reduction under hydrogen flow of a 25% Co/SiO2 catalyst for the hydrocarbons synthesis have been followed in situ by Extended X-Ray Adsorption Fine Structure Spectroscopy (EXAFS). The analysis of the EXAFS spectra enables the identification of a Co3O4 spinel phase before treatment. The two step reduction of Co3O4 to CoO then Co degrees, as observed by EXAFS, is consistent with the studies in XPS (surface) and TPR (bulk). The coordination number of cobalt has been determined at each reduction step.