Operando studies of supported Co-Sn nanoparticles unravel the nature of the most active sites for CO hydrogenation
Résumé
This work shows that it is possible to selectively poison cobalt using small concentrations of Sn. In addition, Sn appears to be preferentially titrating sites on which bridged CO(ads) are formed. This suggests that the sites associated with the bridged sites (possibly edges or steps) are the most active sites for Fischer-Tropsch synthesis. Step sites have already been proposed as being the most active sites for CO dissociation. Methanol formation fitted less the linear relationship, possibly because it does not require CO dissociation and was shown to also involve formate species, located at the interface with the metal particles and an oxidic phase (CoOx or the support).