Dynamics of Ion Binding to Graphene Nanostructures

We model the dynamics of ion binding to graphene nanostructures. In order to disclose the likely ion binding dynamics, we first perform scanned single-point DFT calculations of monovalent ions (Na+, Li+, Cl-, F-) at fixed distances above planar graphene-like H-passivated molecules of different shapes and sizes. The scans reveal intriguing details about the ion-nanostructure potential energy and charge transfer surfaces. We correlate these static results with our room-temperature quantum molecular dynamics simulations of the ion molecule systems, performed in both vacuum and water. Our simulations show that anions either are physisorbed onto the nanostructures or covalently bind at their selected regions, depending on the initial conditions, while cations only physisorb onto them.