Preparation of nitrogen-doped porous carbon and its water adsorption behaviour

In this study, nitrogen-doped porous carbons were prepared by high-temperature carbonization of resorcinol-formaldehyde cryogels, which were synthesized with nitrogen precursor (either urea or melamine) added during the synthesis. The pore structure of the resulting carbon was found to depend on the nitrogen precursor added and its concentration. To quantify the extent of the surface hydrophilicity, which is due to the effect of nitrogen doping, we carried out water adsorption at 298 K, and found that the adsorbed amount of water is proportional to the nitrogen content over the low-pressure region (P/P0 < 0.3). In addition, this amount correlated with the pore structure in the intermediate and high-pressure regions. The adsorption isotherms were analyzed with the Horikawa-Do model to quantify the amount of nitrogen doped during water adsorption