Rethinking the Reaction Pathways of Chemical Reduction of Graphene Oxide

ABSTRACT Although the methods of chemical reduction of graphene oxide have been intensively and well investigated, the reduction mechanism is still ambiguous to date. The reduction mechanisms proposed so far were limited to explain a specific reducing agent rather than a general accessible approach. Here, we suggest that the core issue of chemical reduction of graphene oxide is the reduction of hydroxyl groups. Fundamental reactions mechanisms - E1 and E1cB - are proposed and studied as a general applicable but conclusive reduction mechanism. Density Functional Theory calculation was used to investigate both reaction pathways for the acid- and base-induced reductions. The calculation results show that both reaction pathways are favorable on kinetics and thermodynamics. By applying this reduction mechanism, we developed NaSH as a novel and efficient reducing agent to reduce GO at room temperature, which further confirms the feasibility of the proposed reaction pathways. This work is thus able to propose possible reaction pathways for various chemical reduction methods and will help mature novel reduction approaches.