Na2CO3/Al2O3 is one potential medium that could be used for CO2 capture technology. In recent years, its carbonation and regeneration behaviors have been well-studied, and it is understood that Na2CO3/Al2O3 demonstrates a high CO2 capture capacity. Its main drawback is the unsatisfactory CO2 adsorption rate. Because the total uptake of CO2 principally depends upon the adsorption in the first 10 min, the increase of the absorption rate in the first 10 min could be greatly significant and valuable. An addition of MgO to Na2CO3/Al2O3 is considered for a cyclic Na2CO3/NaHCO3-based CO2 capture process. Scanning electron microscopy and X-ray diffraction characterization of Na2CO3/MgO/Al2O3 indicate that, besides Na2CO3, MgO also participates in the CO2 absorption reaction and generates a new compound Mg6Al2CO3(OH)1(6)center dot 4H(2)O. Moreover, the uptakes of CO2 and the adsorption rates are observed to increase obviously, especially in the first 10 min.