The Equilibrium Stability of 〖CH〗_4 and 〖CO〗_2 on the Calcite (10.4) Surface: an Atomistic Thermodynamics Investigation

Abstract

The present study utilized the ab initio atomistic thermodynamics technique to assess the stability of pure carbon dioxide and pure methane on the calcite(10.4) systems. The stability of configurations 0.5 ML-A2, 0.75 ML-A2, and 0.75 ML-A1 in CH_4/calcite (10.4) systems was shown to be considerable, but only within a limited range of chemical potential. The 1.0 ML-A1 and 1.0 ML-A2 systems of CH_4/calcite (10.4) demonstrated remarkable stability throughout a wide range of chemical potentials. The predominant stable forms for CO_2/calcite (10.4) systems are the 1.0 ML-B2 and 1.0 ML-A4 structures. The surface free energy phase diagrams demonstrate that CO_2 is more favourable than CH_4 for adsorption on the calcite (10.4) surface.