  An ab initio density functional study was performed investigating the
adsorption of CO$_2$ on the neutral boron B$_{n}$ ($n = 10-13$) clusters,
characterized by planar and quasiplanar ground-state atomic structures. For all
four clusters, we found strong chemisorption energy of CO$_2$ reaching 1.6 eV
for B$_{12}$ at the cluster edge sites with the adsorbed molecule in the plane
of the cluster. A configuration with chemisorbed dissociated CO$_2$ molecule
also exists for B$_{11}$ and B$_{13}$ clusters. The strong adsorption is due to
the bending of the CO$_2$ 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 CO$_2$
molecule facilitates the transfer of excess electronic charge from the cluster
edges to the molecule.
