The strong effect of substituents on the carbonyl reduction in graphene oxide: A DFT study

Mechanism of carbonyl reduction by ammonia has been computed by density functional theory. The effects of oxygen- and nitrogen-containing groups on carbonyl reduction were also explored. The results indicate that direct decarbonylation of graphene oxide (GO) is very difficult because of a quite high energy barrier. Although energy barrier reduced greatly when ammonia as a nucleophilic reagent attacked carbonyl group, it is still an endothermic reaction and difficult to occur. The other substituents, involving hydroxyl, carboxyl, epoxy, and pyrrolic-like nitrogen, are favorable to the ammonia-attack decarbonylation, where the hydroxyl group gives the greatest contribution to this process. Their impact strength is correlated with the distance between substituent and carbonyl group. As the distance decreases, the influence strength increases. The present work provides an insight into the reduction mechanism of carbonyl group in GO for experiment.