Collect. Czech. Chem. Commun. 1999, 64, 474-482

Reaction of Nitric Oxide Adsorbed on Platinum Clusters in X Zeolites. Effect of Cluster Size and Nature of Alkali Cations

Libor Brabec

J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic


Adsorption and temperature-programmed desorption of NO was studied over Pt/alkali zeolites. Platinum clusters of three different sizes were prepared by different decomposition routes of [Pt(NH3)4]2+ partially ion-exchanged in NaX zeolite. The effect of various alkali ions (Li, Na and K) was also examined. Similarly to platinum supported by alumina, the conversion of adsorbed NO to nitrogen increases with increasing Pt particle size. Increasing electropositivity of the alkali cations shifts the desorption to lower temperatures.

Keywords: NO; Zeolites; Pt/X; Platinum clusters; Adsorption; Alkali cations; Heterogeneous catalysis.