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Recently, Morishige (Freezing and melting of Kr in hexagonally shaped pores of turbostratic carbon: Lack of hysteresis between freezing and melting Morishige K. J. Phys. Chem. C201111527202726) synthesized a new and exciting porous carbon material that has regular and nonconnected hexagonal pores with graphitic walls. Classical theories, such as the BJH or the DFT method, are unsuitable to characterize this material because the kernel (family of local isotherms) is based on model cylindrical pores. We present in this paper a new characterization based on a GCMC simulation of hexagonal pores that can account for the pore size, the surface morphology, and the heterogeneity arising from either structural or energetic defects. The molecular model describes the adsorption isotherms and the isosteric heat at 77.4 and 87.3 K over a wide range of pressures. This new material and the successful molecular model provide us with an ideal system to study adsorption mechanisms in a confined space, including the effects of confinement on the 2D transition for temperatures below the triple point and the 3D-capillary condensation for temperatures below the critical point of the bulk fluid.

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.