Controlled catalytic properties of platinum clusters on strained graphene

We employed graphene under isotropic strain as the supporting material for Pt clusters (Pt _x, x = 1, 4, or 6) and studied the site-resolved molecular adsorption behaviors of H ₂, CO, and OH on the clusters using ab initio calculations. It was shown that the applied strain enhances the binding of the Pt atom or clusters on the graphene, which lowers the average energy of the d electrons (d-band center). However, for the Pt ₄ and Pt ₆ clusters that form two Pt atomic layers on the graphene, only the d-band center of the bottommost Pt layer can be readily tuned by the external strain on graphene. However, the site-resolved calculations of molecular binding demonstrate that controlling the d-band center of the bottommost Pt atoms can be a substantial factor for all the catalytic activities of the Pt cluster. We also found that the stability of the Pt/graphene system was enhanced by applying strain to the graphene support.