Hydrogen chemisorption capability of reduced graphene oxide membranes

Reduced Graphene Oxide (rGO) is an extremely variable material, whose structure and composition depend on the synthesis procedure. Therefore, studies aimed at relating the structural properties to the chemical and physical properties are needed to optimize the materials for specific applications. In this work, the hydrogen chemisorption capacity of rGO is theoretically characterized as a function of its composition and structural features. A comprehensive database of model systems is generated using Molecular Dynamics (MD) simulations with reactive potentials. These structures are subsequently exposed to atomic hydrogen to evaluate their reactivity. A statistical analysis is performed to quantify hydrogen adsorption capabilities and stability, establishing correlations with the structural properties and composition of the material. We find that oxygen content in the structure can be tuned by modulating the temperature during thermal reduction and the H pressure during chemical reduction. We also find that reversible H chemisorption on internal C sites is controllable by the amount of oxygen in the structure. These findings offer practical ways to optimize the rGO as a storage medium for reversible electrochemical H loading.