Catalyst poisoning in the conversion of CO and N 2O to CO 2 and N 2 on Pt 4 - In the gas phase

Pt₄ ^- catalyses the conversion of CO and N ₂O to CO₂ and N₂ in the gas phase, as observed by Fourier transform ion cyclotron (FT-ICR) mass spectrometry. The partial pressures of CO and N₂O determine the extent of poisoning and the turnover numbers that can be achieved. The catalytic conversion terminates as soon as two CO are adsorbed on the cluster. With N₂O, the reactivity of Pt₄O₂ ^- and Pt₄O₃ ^- is reduced to 41% and 34% compared to Pt₄O^-, respectively, and with Pt₄O₄ ^- this value is reduced to 1%. In contrast, Pt₄ ⁺ shows no apparent catalytic activity. Density functional theory calculations of Pt₄ ^+/- with CO and N₂O adsorbates reveal significantly different stabilities of the reaction intermediates for the different charge states. © EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2007.