Thermal Decomposition of Hydrated Graphite Oxide: A Computational Study

Abstract

We study the behavior of hydrated graphite oxide (GO) at high temperatures using thermally-accelerated molecular dynamics simulations based on ab initio density-functional theory. Our results suggest that GO, a viable candidate for water treatment and desalination membranes, is more heat resilient than currently used organic materials. The system we consider to represent important aspects of thermal processes in highly disordered GO is a hydrated GO bilayer in a vacuum. Our study provides microscopic insight into reactions involving water and functional epoxy-$\mathrm{O}$ and $\mathrm{OH}$ groups bonded to graphene layers, and also describes the swelling of the structure by water vapor pressure at elevated temperatures. We find the system withstands simulation temperatures up to approximately $2500\phantom{\rule{0.2em}{0ex}}\mathrm{K}$ before the graphitic layers start decomposing, implying the possibility of cleaning biofouling residue from a GO-based membrane by heating it in an inert-gas atmosphere.