Density functional theory studies of methanol adsorption and decomposition mechanism on Al13 clusters

Abstract

The adsorption and decomposition of the CH3OH molecule on Al13 clusters were investigated by generalized gradient approximation of the density functional theory. The strong attractive forces between the CH3OH molecule and aluminum atoms induce the breaking of the H–O and C–O bonds of CH3OH. Subsequently, the dissociated CH3O and OH radical fragments oxidize the aluminum clusters. The largest adsorption energy is –205.4 kJ/mol. We also investigated five reaction pathways of the CH3OH molecule on the Al13 clusters. The activation energies are in the range of 10.3−113.1 kJ/mol. Compared with the bond dissociation energies of the C–O and O–H bonds in the isolated methanol, Al13 performs very well in decreasing the bond break barrier of CH3OH. In addition, although the C–O bond is slightly weaker than the O−H bond, the O−H bond is even easier to decompose on the Al13 surface. The rate constants of five adsorption paths over the temperature range 300−700 K are presented.