Platinum–carbide interactions: core–shells for catalytic use

Abstract

A selection of carbides (TiC, NbC, TaC, WC and SiC) have been studied using density functional theory. Their calculated adsorption characteristics towards Pt overlayers are presented with a view to the use of the carbides as core–shell components. WC hcp and SiC are observed to support Pt overlayers on all surfaces making them promising candidates for full Pt encapsulation. Pt adsorption on fcc (111) carbide surfaces is observed to take place with the transition metal surface resonances (TMSRs) playing a key role whilst fcc (100) are universally unfavourable towards Pt adsorption. The effect of the carbide supports on oxygen binding on the Pt overlayer is also considered and discussed in relation to the oxygen reduction reaction (ORR). The oxygen adsorption study revealed several Pt–WC surfaces which exhibit reduced oxygen adsorption energies, suggesting they should promote or maintain ORR activity with respect to nanoparticulate Pt catalysts.