CO oxidation on Al[sbnd]Au nano-composite systems

Abstract

Using first principles method we report the CO oxidation behaviour of AlAu nano-composites in three different size ranges: Al6Au8, Al13Au42 and a periodic slab of AlAu(1 1 1) surface. The clusters prefer enclosed structures with alternating arrangement of Al and Au atoms, maximising Auδ−Alδ+ bonds. Charge distribution analysis suggests the charge transfer from Al to Au atoms, corroborated by the red shift in the density of states spectrum. Further, CO oxidation on these nano-composite systems was investigated through both Eley – Rideal and Langmuir Hinshelwood mechanism. While, these clusters interact with O2 non-dissociatively with an elongation of the OO bond, further interaction with CO led to formation of CO2 spontaneously. On contrary, the CO2 evolution by co-adsorption of O2 and CO molecules has a transition state barrier. On the basis of the results it is inferred that nano-composite material of AlAu shows significant promise toward effective oxidative catalysis.