CO oxidation mechanism on AlAun

Abstract

CO oxidation via LH mechanism on AlAun (n=1–12) have been studied by density functional theory calculations with the aim to shed light on reaction mechanism and catalytic activity of AlAu alloy. The AlAun molecular structures and adsorption energies of a single CO or O2 molecule as well as coadsorption energies of CO+O2, CO2+O, and CO+O on various distinctive sites of each AlAun are predicted. The calculated results show that the overall LH, AlAun+O2(gas)+CO(gas)→AlAun–O2(ads)+CO(ads)→AlAun–OOCO(ads)→AlAun–O(ads)+CO2(gas)→AlAun–O(ads)+CO(ads)→AlAun–OCO(ads)→AlAun+CO2(gas) is calculated to by exothermic by −144.8kcal/mol. It suggests that the CO oxidation catalyzed by the AlAu6 and AlAu12 is likely to occur at or even below room temperature. AlAu6 and AlAu12 exhibit a larger catalytic activity for CO oxidation by O2 molecule.