Oxidation and decomposition mechanisms of air sensitive aluminum clusters at high heating rates

Abstract

Molecular near zero oxidation state clusters of metals are of interest as fuel additives. In this work high heating rate decomposition of the Al(I) tetrameric cluster, [AlBr(NEt3)]4 (Et=C2H5), was studied at heating rates of up to 5×105K/s using temperature-jump time-of-flight mass spectrometry (T-jump TOFMS). Gas phase Al and AlHx species were rapidly released during decomposition of the cluster, at ∼220°C. The activation energy for decomposition was determined to be ∼43kJ/mol. Addition of an oxidizer, KIO4, increased Al, AlO, and HBr signal intensities, showing direct oxidation of the cluster with gas phase oxygen.