Pillared Covalent Organic Frameworks with Balanced Volumetric and Gravimetric Hydrogen Uptake

On the basis of our modeling of pillared covalent organic frameworks (PCOFs) with pyridine molecules inserted between the COF-1 layers, we propose that the surface area and free volume of storage materials should be balanced to increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and grand canonical Monte Carlo simulations show that these PCOFs have significantly improved gravimetric and volumetric hydrogen storage capacities of 8.8–10.0 wt % and 58.7–61.7 g L –1, respectively.