We have computed the phase diagrams for multi-component M–C–O–H (M=Li, Na, K) systems using first-principles density functional theory complemented with lattice phonon calculations. We have identified all CO2 capture reactions that lie on the Gibbs free energy convex hull as a function of temperature and the partial pressures of CO2 and H2O. Our predicted phase diagrams for CO2 capture reactions are in qualitative and in some instances quantitative agreement with experimental data. The Na2CO3/NaHCO3 and K2CO3/KHCO3 systems were found to be the most promising candidates of all those we investigated for both pre- and post-combustion CO2 capture. Overall, we show that our calculation approach can be used to screen promising materials for CO2 capture under different conditions of temperature and pressure.
The calculated results indicate that the Na2CO3/NaHCO3 and K2CO3/KHCO3 systems are the most promising candidates of all those we investigated for both pre-and post-combustion CO2 capture.