CO_2 capture properties of MCOH (M=Li, Na, K) systems: A combined density functional theory and lattice phonon dynamics study

摘要

We have computed the phase diagrams for multi-component MCOH (M=Li, Na, K) systems using first-principles density functional theory complemented with lattice phonon calculations. We have identified all CO_2 capture reactions that lie on the Gibbs free energy convex hull as a function of temperature and the partial pressures of CO_2 and H_2O. Our predicted phase diagrams for CO_2 capture reactions are in qualitative and in some instances quantitative agreement with experimental data. The Na_2CO_3/NaHCO_3 and K_2CO _3/KHCO_3 systems were found to be the most promising candidates of all those we investigated for both pre- and post-combustion CO_2 capture. Overall, we show that our calculation approach can be used to screen promising materials for CO_2 capture under different conditions of temperature and pressure.