  A principle of enhancement CO adsorption was developed theoretically by using
density functional theory through doping Al into graphene. The results show
that the Al doped graphene has strong chemisorption of CO molecule by forming
Al-CO bond, where CO onto intrinsic graphene remains weak physisorption.
Furthermore, the enhancement of CO sensitivity in the Al doped graphene is
determined by a large electrical conductivity change after adsorption, where CO
absorption leads to increase of electrical conductivity upon via introducing
large amount of shallow acceptor states. Therefore, this newly developed Al
doped graphene would be an excellent candidate for sensing CO gas.
