Generalized reaction mechanism for the selective aerobic oxidation of aryl and alkyl alcohols over nitrogen-doped graphene

Abstract

In this study, an attempt has been made to investigate the mechanistic pathway for the aerobic oxidation of alcohols over nitrogen-doped graphene using density functional theory methods employing a suitable model for graphene. The formation of activated oxygen species (AOS), upon oxidation, by dioxygen has been investigated with the aid of various possible nitrogen-doped models. The detailed reaction mechanism for the oxidation of benzyl alcohol and ethanol by the three AOS obtained in the present study has been unraveled. Results indicate that the ketonic oxygen species oxidizes aromatic alcohol with minimum activation energy of ∼26.5 kcal/mol. On the contrary, the activation energy for the oxidation of alkyl alcohol by AOS present at the center is the lowest, which is also similar to that of ketonic oxygen species. On the basis of the results, a generalized reaction mechanism has been arrived for alcohol oxidation by nitrogen-doped graphene. Findings reveal the valuable lead information for the optimal control over selective oxidation of alcohol by N-doped graphene based on dopant concentration and temperature.