Formation of CHx species from CO dissociation on double-stepped Co(0001):: Exploring Fischer-Tropsch mechanism

Spin-polarized density functional theory calculations have been performed to investigate the formation of CHx species from CO dissociation on the double-stepped Co(0001) surface. It is found that the steps not only favor CO dissociation but also are an advantage over CO and C/O hydrogenation. Furthermore, the step with the hcp and fcc sites in alternate arrangement is more active than the other consisting of the 4-fold site. Under realistic Fischer-Tropsch reaction conditions, surface CHxO are the most favored intermediates; and surface CHx are formed from CHxO dissociation, while the direct CO dissociation with carbide intermediate is not competitive.