Controlled Catalytic Properties of Platinum Clusters on Strained Graphene

We employed biaxially strained graphene as the supporting material for Pt clusters (Pt$_{x}$, x=1, 4 or 6) and studied the molecular adsorption behaviors of H$_{2}$, CO and OH on the cluster using ab initio calculations. It was shown that the applied strain enhances binding of the Pt cluster on the graphene, which lowers the average energy of Pt d electron (d-band center). The binding energies of H$_{2}$, CO and OH on Pt$_{1}$/graphene are strongly correlated with the d-band center modulated by the graphene strain. The calculations with small Pt clusters (Pt$_{4}$ and Pt$_{6}$) also show that the d-band center is a substantial factor for the catalytic activity of the Ptx/graphene system. We also found that the stability of the Pt clusters was enhanced by applying the strain on the graphene support.