High-Pressure Hydrogen Adsorption on a Porous Electron-Rich Covalent Organonitridic Framework

We report that a porous, electron-rich, covalent, organonitridic framework (PECONF-4) exhibits an unusually high hydrogen uptake at 77 K, relative to its specific surface area. Chahine's rule, a widely cited heuristic for hydrogen adsorption, sets a maximum adsorptive uptake of 1 wt % hydrogen at 77 K per 500 m² of the adsorbent surface area. High-pressure hydrogen adsorption measurements in a Sieverts apparatus showed that PECONF-4 exceeds Chahine's rule by 50%. The Brunauer-Emmett-Teller (BET) specific surface area of PECONF-4 was measured redundantly with nitrogen, argon, and carbon dioxide and found to be between 569 ± 2 and 676 ± 13 m² g^-1. Furthermore, hydrogen on PECONF-4 has a high heat of adsorption, in excess of 9 kJ mol^-1.