Electric Field Effects on the Adsorption of CO on a Graphene Nanodot and the Healing Mechanism of a Vacancy in a Graphene Nanodot

It is well known that the external electric field can effectively modify the electronic structures and transport properties of low-dimensional systems. However, to our knowledge, the corresponding atomic structure and adsorption property changes of a graphene carbon network under different applied electric fields have not been investigated. Herein, using first-principles DFT calculations, we have systematically explored the CO adsorption on the pristine graphene nanodot and the defective one by taking the external electric field into account. It is found that the electric field can increase the CO adsorption energy and there is a barrier for CO-vacancy recombination that is mostly believed to remerge instantaneously when they come close to each other. Also, we proposed a mechanism for the subsequent healing of a monovacancy on a graphene nanodot by interaction with CO molecules, leading to the restoration of a pristine hexagonal carbon network.