Dynamic characterization of surfaces of Co/TiO2 Fischer-Tropsch catalysts with infrared spectroscopy and DFT calculations

Although Fischer-Tropsch (F-T) technology has been known for more than 80 years, the information on the fundamentals of the catalytic chemistry is limited, hindering improvements in process development. With respect to the reaction mechanism, most publications generally consider the same limited number of reaction pathways but reach different, often mutually exclusive, conclusions. Specifically for cobalt-based catalysts, traditional reaction models assume static metallic Co as the only active catalytic sites. Our studies, however, suggest that it is important to take into account changes not only in the concentrations of active and spectator surface species, but also in the composition and structure of the catalyst bulk, subsurface and surface. By tightly integrating reaction measurements, catalyst characterization, spectroscopic studies and DFT calculations with vibrational analyses, we are developing new methodologies for detection and description of dynamic changes in the composition and structure of catalytic surfaces under reaction conditions.