Theoretical characterization of reduction dynamics for graphene oxide by alkaline-earth metals

First-principles calculation identifies elementary processes in the thermal reduction of graphene oxide (GO) and reveals the effects of alkaline-earth metals (AEMs) in recovering the graphene. These metals are highly effective in removing residual oxygen groups resistive to thermal reduction, as well as healing the defects formed during the reduction, such as the carbonyl groups. In the AEM-assisted reduction, the AEMs serve as an electron reservoir of high chemical potential that forces electron transfer to the GO, whereas pristine carbon regions on the GO serve as a bridge to facilitate the electron transfer directly to oxidized carbon. This enables fast kinetics for the breaking of both C-O and C=O bonds. Complete reduction is observed in our simulation at T <= 600 K within 32 ps for a 28%-oxygen-coverage GO model. (C) 2012 Elsevier Ltd. All rights reserved.