Hydrogen-assisted CO dissociation on the Co(211) stepped surface

Abstract

In the Fischer–Tropsch synthesis (FT) process the mechanism of CO dissociation is of fundamental importance. In this study we compare hydrogen-assisted CO dissociation mechanisms to direct CO dissociation on the B₅ site as exposed on the fcc-Co(211) surface. Whereas direct CO dissociation is calculated to have an overall barrier of 142 kJ mol⁻¹, the alternative mechanism involving a HCO intermediate proceeds with a lower overall barrier of 123 kJ mol⁻¹. Using these calculated values we show that hydrogen-assisted CO dissociation will result in an overall rate corresponding to the same order as the considered FT experiments.