Theoretical investigation of the catalytic and inhibiting role of boron in graphene oxidation

Abstract

Boron has been considered as an important promising candidate for oxidation protection in carbon materials. However, the experimental discovery of catalytic effect of boron in graphite makes the role of boron confusing. To better understand the role of boron in carbon materials such as graphite or graphene, we investigate the oxidation behavior of boron-doped stoichiometric and vacancy-defected graphene plane by density functional theory calculations. Boron is found to be a catalyst for oxidation in the stoichiometric surface, while it acts as an inhibitor in the vacancy-defected surface. The electronic properties are calculated to explain why boron behaves differently in different surfaces. We show that the role of boron is closely associated with the redistribution of σ electrons. For instance, the introduction of boron in stoichiometric surface facilitates the delocalized σ electrons transfer from the matrix to oxygen and the adsorption energy increases with the number of transferred σ electrons; while the decrease in reactivity with boron substitution in the vacancy-defected surface is largely attributed to the transition of electrons from delocalized states to localized states, thus suppressing the activity of dangling C atoms. This work helps to provide a theoretical foundation for further investigation of oxidation-resistant carbon materials.