Complete Inhibition of Pt Site Poisoning and Efficient Carbon Monoxide Oxidation Induced by Vanadium and Cobalt*

A complete solution for CO poisoning of Pt catalysts, requires a design that entirely prevents CO adsorption on Pt atoms. We explored the CO adsorption sites and oxidation capability of 3d transition metal doped small magic clusters of Pt₄. Among Pt₃M, only Pt₃V free-standing cluster entirely eliminates the prospect of Pt poisoning by inverting the adsorption site of CO to V atom. V d-band center lies closer to the Fermi-level than that of Pt atoms, resulting in larger number of empty d-antibonding states, thereby, making V comparatively more reactive towards CO. The inversion of CO adsorption site, is also observed for larger Pt_nV_m clusters and becomes possible for Pt_nCo_m clusters for sizes larger than m+n=12. A maximum catalytic efficiency is attained for Pt₄₁V₁₄, which at room temperature gives a CO₂ turn over frequency comparable to the conventional catalysts. The oxidation of CO becomes more favourable by Mars van Krevelan than Langmuir Hinshelwood mechanism for the cluster supported on vacancy prone Li-doped MgO(100). Our results present a rationale design of Pt poisoning free fuel cells and automobile exhaust catalyst.