Unless explicitly stated in the caption, properties are averaged over an (N, V, T ) trajec-tory of 1 ns for classical MD simulations and 60 ps for ab initio simulations. For classical MD, frames are taken every 1 ps for the radial distribution function (RDF) and bond angle distribution, and every 50 ps for pore statistics. For ab initio MD, those intervals are respectively of 0.5 fs and 0.5 ps.