Adsorption energies and prefactor determination for CH3OH adsorption on graphite.

摘要: In this paper, we have studied adsorption and thermal desorption of methanol CH3OH on graphite surface, with the specific aim to derive from experimental data quantitative parameters that govern desorption, namely, energy Eads prefactor ν Polanyi-Wigner law. low coverage regime, these two values are interconnected usually experiments can be reproduced any couple (Eads, ν), which makes intercomparison between studies difficult since results depend extraction method. Here, use a method for determining independently average value works over large range incident coverage, limited set curves performed at different heating rates. regime procedure is based first order kinetic law, considers an distribution not expected vary applied rate. case multilayers, determined as 430 meV 5 × 10(14) s(-1). For submonolayers graphite, 470 ± 30 (8 3) 10(16) s(-1) been found. These last values, do change 0.09 ML 1 initial suggest molecules form island-like structure even coverage.