Composition and size dependent methane dehydrogenation on binary gold-palladium clusters

Methane adsorption and possible dehydrogenation mediated by the free gold-palladium clusters Au2Pd+, AuPd2+, and Au2Pd2+ have been investigated in an ion trap experiment under multi-collision conditions. Temperature dependent kinetic measurements identify the palladium-rich AuPd2+ as the only one among these clusters which is able to dehydrogenate methane. The comparison with previously measured reactions of the bare gold Au-n(+) (n = 2-4) as well as the bare palladium Pd-m(+) (m = 2-4) clusters allows to obtain insights into cluster size and composition dependent reaction mechanisms, kinetics, and methane binding energies. (C) 2013 Elsevier B.V. All rights reserved.