1LB-4 : A Fundamental Understanding of MgO-based CO 2 Sorbents

MgO is regarded as the most promising sorbent for intermediate temperature CO2 capture due to its abundance in basic sites, high stability, and lower energy requirement for regeneration. However, the CO2 sorption capacity of MgO is significantly hindered by its relatively slow kinetics and tendency to agglomerate after high-temperature regeneration. Recently, MgO-based sorbents promoted by alkali salts and binary or ternary eutectic mixtures have gained much attention for intermediate temperature CO2 capture due to their improved CO2 uptake and MgO conversion. However, the chemistry behind this promoting effect of eutectic mixture to MgO-based sorbents still remains unclear. In this work, we successfully carried out the direct observation of the sorption of gaseous CO2 over molten EM-promoted solid MgO via in situ TEM. We report the feasibility of using commercially available hydrotalcites as stabilizing additives for NaNO3-promoted MgO sorbents.