Rumpled graphite basal plane as a model heterogeneous carbon surface

Abstract

A new model is suggested for the heterogeneous surfaces of nongraphitized carbon adsorbents. It may be called the rumpled graphite basal plane (RGBP). The atomic structure of RGBP can be obtained by squeezing a graphite basal plane in a molecular dynamics computer simulation under a random distribution of initial atomic velocities. The empirical Tersoff potential describes the carbon–carbon interactions. The degree of squeezing is chosen to reproduce the main features of the x-ray interference function of nongraphitized carbon blacks. Grand canonical ensemble Monte Carlo simulation of the isotherms of adsorption of N2 on RGBP reproduce experimental isotherms on these carbon blacks reasonably well, especially in the BET region of relative pressures.

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

“…The evaluation of the PSD using the NLDFT kernel has shown that it is a reliable method for the characterization of certain materials, such as ordered silica, while it is difficult to analyze carbon materials. DFT methods were suggested for the study of the PSD of activated carbons [60][61][62][63][64], but the complexity regarding the heterogeneity of their porous structure has prompted the development of new characterization methods, which remains a current problem. As mentioned before, the NLDFT kernel for particularly carbonaceous materials is based on slit-independent pores with ideal graphite walls.…”

Characterization of activated carbon fibers using argon adsorption

“…Thus, the question arising is ''what are possible surface heterogeneities important in such high surface area carbon fibers?'' Bakaev [40] suggested the rumpled graphite basal plane (RGBP) model, whereby carbon surface roughness due to surface tension is considered as heterogeneous carbon surface or secondary surface heterogeneity (SSH), distinguished from the primary surface heterogeneity (PSH) arising from surface roughness at smaller scale of length. He concluded that while SSH is responsible for the shape of the adsorption isotherm in the BET region PSH determines shape of adsorption isotherm in the sub-monolayer region.…”

Molecular Modeling of Porous Carbons Using the Hybrid Reverse Monte Carlo Method

“…These constraints may be physical or chemical and are based upon the understanding of the material being modeled. RMC has been used before in modeling amorphous nonporous carbons incorporating different constraints, such as the ratio of sp 2 to sp 3 sites, coordination number constraints, bond angle constraints, etc. − Thomson and Gubbins modeled a porous carbon as a collection of graphene microcrystals and used the following constraints: (1) an atom can only have two or three neighbors, (2) all interatomic distances are 1.42 Å, (3) all bond angles are 120°. In their final model the pores were slit shaped but connected and the model allowed for the walls to depart from being parallel.…”