A COMPARISON OF 2 SURFACE VIRIAL ANALYSES OF MONATOMIC GASES ON GRAPHITE AND BORON-NITRIDE

By examining monatomic gases (argon, krypton, and xenon) adsorbed on P33 graphite and hexagonal boron nitride, a two-surface model to represent gas-solid interaction systems was developed. Second gas-solid virial coefficients were used in conjunction with a Lennard-Jones (16,3) potential to determine the gas-solid interaction energy, the surface area, and the percentage area of the higher energy surface for both gas-P33 and gas-boron nitride systems. The analyses indicated that P33 graphite is best characterized as a single-surface solid, while boron nitride is best characterized as a two-surface solid. This two-surface virial approach was able to clearly distinguish the two types of surfaces using the temperature dependence of Henry's law adsorption data, but without any specific prior assumptions of differences in surface structures. © 1992.