Roles of double salt formation and NaNO3 in Na2CO3-promoted MgO absorbent for intermediate temperature CO2 removal

► We describe Na2CO3-promoted MgO as a CO2 absorbent in the range of 300-470 °C. ► The material shows a regenerable capacity of 3.4 mmol/g both through TSA and PSA. ► Na2Mg(CO3)2 double salt has a free energy of formation of approximately −122 kJ/mol. ► The absorbent is predicted to be able to remove 85-90% of CO2 in pre-combustion application. ► NaNO3 is found to have an important role in facilitating the CO2 absorption of the double salt.