Computational design of a hydrogenated porous graphene membrane for anion selective transport

Porous graphene materials with similar subnanometer pore sizes are promising in molecular sieving and controlled nanofluid transport. The design and fabrication of efficient porous membranes are still challenging due to lack of understanding on basic molecular mechanism, especially for ion selection. Here we computationally designed a hydrogenated porous membrane on a graphene sheet for anion selection. First, we explored the ion hydration layers of Na+ and Cl− ions when placed at pore center. Combined with ion selectivity under external voltage and free energy calculation, we found that the ion selectivity alternation is affected by two competitive molecular mechanisms: hydration layer peeling and electrostatic selection. We also discussed the design principles from our results for optimization. We expect that our work benefit for the design process of new-generation two-dimensional molecular sieves.