Strong chemisorption of CO₂ on B₁₀–B₁₃ planar-type clusters
An ab initio density functional study was performed investigating the adsorption of CO₂ on neutral boron Bₙ (n = 10–13) clusters that are characterized by planar and quasiplanar ground-state atomic structures. For all four clusters, we found large chemisorption binding energies, reaching 1.6 eV between CO₂ and B₁₂, with the adsorbed molecule oriented in the plane of the cluster and adsorbed along the cluster edge. A configuration with chemisorbed dissociated CO₂ molecule also exists for B₁₁ and B₁₃ clusters. The strong adsorption is due to the bending of the CO₂ molecule, which provides energetically accessible fully in-plane frontier molecular orbitals matching the edge states of the clusters. At the same time, the intrinsic dipole moment of a bent CO₂ molecule facilitates the transfer of excess electronic charge from the cluster edges to the molecule.