Interaction of Pd cluster anions (Pd- n , n < 11) with oxygen

Abstract

Interactions between oxygen and Pd cluster anions were studied using Time-of-Flight (ToF) mass spectrometry and Ultraviolet Photoelectron Spectroscopy (UPS). In contrast to the coinage metal clusters, no pronounced size selectivity towards chemisorption of oxygen molecules can be observed for the Pd cluster anions: regardless of the cluster size, no more than 2 oxygen molecules can be attached to a cluster. When PdnO− m clusters are prepared by pre-dissociation of oxygen molecules by electric arc and post-reaction with Pd, the proportion of Pd cluster anions reacted with oxygen does not much change compared to the case of the reaction between Pd cluster anions and O2 molecules. This result indicates that the O2 chemisorption on Pd cluster anions does not involve large activations barriers: using different synthesis method of a cluster, one can get a better insight into the chemisorption routes of molecules on metal clusters.