Interaction of hydrogen with palladium–copper nanoalloys

Abstract

Doping porous carbons with palladium nanoparticles is known to enhance the hydrogen storage capacity of these materials. Alloying palladium with the non-expensive metal copper will reduce the cost of the nanoparticles. We have studied how alloying with copper affects the hydrogen adsorption properties of CumPdn clusters with m\u2009+\u2009n\u2009=\u20096. Formation of CumPdn nanoalloys is favorable, a fact consistent with the formation of bulk solid Cu–Pd alloys. Molecular adsorption of H2 and dissociative chemisorption are both exothermic, and dissociative chemisorption is energetically favorable compared to molecular adsorption. The geometric structures of the CumPdn clusters are maintained, in general, after molecular or dissociative adsorption of H2, with very few exceptions. Adsorption binding energies on some alloy nanoclusters rich in Cu are higher than adsorption binding energies on Pd6, so alloying with Cu may become a way to improve hydrogen adsorption in Pd-doped porous carbon materials.