PVT properties and diffusion characteristics of H₂O/H₂/CO₂ mixtures in graphite nanoslits

We study the PVT properties and diffusion characteristics of H₂O/H₂/CO₂ mixtures confined in graphite nanoslits via molecular dynamics simulations. The results show that the pressure decreases with increasing molar volume and increases with increasing slit-width except for the narrow width d = 6 Å due to the dominating repulsive surface forces. Diffusion coefficients of components increase with increasing molar volume or slit-width, and increase with increasing temperature except for H₂ owing to competitive adsorption. Moreover, H₂O component with the highest mole fraction plays a major role in capillary condensation that enhances the ability of H₂O molecules of forming tetrahedral structures.