Theoretical investigation of molecular hydrogen adsorption and dissociation on AlnV(n = 1–13) clusters

We present density functional calculations of H2 adsorption and dissociation on small-sized AlnV clusters for n = 1–13. The growth pattern for AlnV (n = 2–4, 8, 10–12) clusters is V atom occupying a peripheral position of Aln clusters. And the growth pattern for AlnV (n = 6, 9, and 13) clusters is V-substituted Aln+1 clusters. It is found that the V atom substituted the surface atom of Aln+1 cluster and occupies a peripheral position. H2 is easily physically absorbed on the top V atom of AlnV (n = 1–13) clusters with a side-on orientation rather than an end-on orientation because of the more effective orbital overlap in the side-on orientation. The reaction of AlnV with H2 would produce AlnVH2 because of large exothermic energy changes and relatively small activation energies especially for AlV and Al7V, which might serve as highly efficient and low-cost catalysts for hydrogen dissociation.