In situ and operando x-ray diffraction and x-ray absorption studies of Co–TiO2 dry methane reforming catalysts

Abstract

In situ and operando powder x-ray diffraction and x-ray adsorption spectroscopy was used to study the structural and electronic changes occurring in various Co–TiO2 catalysts used for the dry reforming of methane. The experimental data showed that large structural changes occur in these catalysts under catalyst activation and reaction conditions. The variations observed in the TiO2 polymorph type, morphology, surface area, particle size as well as Co oxidation state all contribute to the observed catalytic activity as well as catalyst deactivation giving direct evidence for the deactivation mechanisms. The deactivation of the catalysts can be separated into two distinct events, the first resulting from structural changes occurring during catalyst activation and catalytic reaction, and the second due to gradual Co oxidation over the course of the reaction.