Steady-state reaction kinetics of CO oxidation catalyzed by uni-sized Pt30 clusters directly bound to Si surface

Abstract

The catalytic activities of CO oxidation driven by uni-sized Pt clusters directly bound to a Si substrate surface, Pt₃₀/Si, are reported. The CO₂ production rate was measured as a function of the cluster temperature under steady-state conditions with continuous and simultaneous flow of CO and O₂, as well as at fixed reactant exposure followed by a temperature-programmed desorption mass-spectroscopy. The highly selective, sensitive and reliable detection of the catalytic CO₂ products allows the determination of the CO oxidation rate against non-negligible background CO₂, in spite of the Pt in the catalyst sample being as little as 30 ng. It was demonstrated that Pt₃₀/Si is a durable and high-performance CO-oxidation catalyst, even when repeating the reaction cycle in coexistence with CO and O₂ in the temperature range below 630 K. It is probable that the high performance catalytic activity originates from efficient reductive activation of oxygen by electrons enriched at the subnano-interface between Pt₃₀ and the Si substrate surface.