Atomistic insight into enhanced thermal decomposition of energetic material on graphene oxide

Abstract

Graphene oxide (GO)-based nanocomposites are promising additives for practical applications of cyclotrimethylenetrinitramine (RDX). GO is not only an excellent support for nanoparticles, but also has independent catalytic activities, which have not been well understood. In this study, the reactive molecular dynamics simulation method is employed to investigate the kinetics and fundamental catalytic mechanisms of the thermal decomposition of RDX on GO. The RDX decomposition reaction is found to be enhanced in the presence of GO and the catalytic effect is better at low than at high temperatures. Additionally, GO addition lowers the activation energy by 11.35% compared with the thermal decomposition of pure RDX. The study shows that the catalytic capabilities of GO primarily originate from its functional groups that promote both the initiation and intermediate reactions. Furthermore, the H exchange process between the functional groups on GO and RDX/RDX intermediates plays an important role in the reaction. GO is further oxidized with more functional groups during the reaction, which are also involved in the catalytic activities. Finally, the energy barrier of functional group-participated reactions is found to be lower than their corresponding unimolecular decomposition leading to enhanced thermal decomposition of RDX. The proposed catalytic mechanisms in the present research should also be applicable to other energetic materials of the same class with a similar structure as RDX.