Can metal-free silicon-doped hexagonal boron nitride nanosheets and nanotubes exhibit activity toward CO oxidation?

Si-doped hexagonal boron nitride nanosheets (Si-BNNS) and nanotubes (Si-BNNT) have been investigated by first-principle methods. The strong interaction between the silicon atom and the hexagonal boron nitride nanosheet or nanotube with a boron vacancy indicates that such nanocomposites should be very stable. The significant charge transfer from the Si-BNNS substrate to the O-2 molecule, which could occupy the antibonding 2 pi* orbitals of O-2, results in the activation of the adsorbed O-2. The catalytic activity of the Si-BNNS for CO oxidation is explored and the calculated barrier (0.29 eV) of the reaction CO + O-2 -> CO2 + O is much lower than those on the traditional noble metals. This opens a new avenue to fabricate low cost and high activity boron nitride-based metal-free catalysts.