Density functional theory study of high-temperature CO2 adsorption by Li2ZrO3: Effect of typical flue gas components on adsorption energy and electronic properties

Abstract

Lithium zirconate (Li2ZrO3) is one of the best-performing high-temperature CO2 adsorbents, but the effect of flue gas on its mutual mechanism of action is not clear. The adsorption mechanism of CO2 and flue gas components on the Li2ZrO3 (111) surface is investigated theoretically through density functional theory (DFT), where the selected flue gas components are O2, H2O, and SO2. Theoretical calculations show that O2 exhibits physical adsorption and CO2, H2O, and SO2 exhibit chemisorption on the Li2ZrO3 surface. The energy potential barrier for CO2 adsorption on the Li2ZrO3(111) surface is 0.3 eV. CO2 is gradually desorbed at temperatures above 870 K. When there are flue gas atmospheres present, the desorption temperature of CO2 decreases, to a certain extent. All selected flue gas components inhibit the adsorption of CO2, O2, and H2O, weakening the interaction forces between the surface and CO2 and making it less stable. SO2 has the same adsorption sites as CO2, while SO2 has much higher adsorption energy than CO2. SO2 is more likely to adsorb onto and occupy the active sites of CO2.