Pore Size Distribution Analysis of Structure Different Microporous Carbons – Theoretical Evaluation Based on Density Functional Theory and Nitrogen and Argon Experimental Adsorption Isotherms at 77 K

J. Pavlíček and S. J. Scaife

Abstract
Nitrogen and argon adsorption isotherms on four significantly different microporous carbons were experimentally measured at 77K. Non-local density functional theory was used to predict theoretically the behaviour of both gases in slit-shaped pores in adsorption. Adsorbate molecules were modelled as spheres, fluid-fluid and solid-fluid interactions were described by 12–6 Lennard-Jones and 10–4–3 Steele potentials, respectively. Potential parameters were obtained by fitting the calculated data to experimental isotherms of nitrogen and argon on a non-microporous carbon surface. These results were used for the theoretical evaluation of pore size distribution. An algorithm for the pore size distribution analysis from adsorption data (theoretical and experimental) was suggested and tested on the adsorption data obtained.

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Keywords
Density Functional Theory, pore size distribution, adsorption of nitrogen, adsorption of argon, microporous carbons