The rationale development of size-controlled inorganic nanocatalysts has been boosted by the possibility to evaluate their properties using in situ spectroscopy, such high pressure Xray absorption spectroscopy. To this end, a new gas cell was developed to run in a synchrotron environment, at pressures up to 5 bar and temperatures up to 400C.Monodisperse cobalt nanoparticles with diameters spanning a range of 4 nm to 15 nm were evaluated for the first step of the Fischer-Tropsch synthesis: the dissociation of carbon monoxide. They were exposed to CO and/or H2 gas mixtures. The formation of new surface species and the changes in the surface oxidation state were investigated. X-ray absorption spectroscopy revealed a strong dependence of the dissociation kinetics on the nanoparticles diameter. Larger nanoparticles were shown to dissociate CO even at low temperature while smaller ones required heating and exposure to hydrogen.

Size-controlled cobalt nanoparticles for Fischer-Tropsch synthesis: Smaller is not always better

245th National Meeting (2013)

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