Facile Synthesis of Highly Efficient MgO for Catalytically Accelerating CO 2 Absorption in Tertiary Amine Solutions

The industrial application of traditional tertiary amine solutions for CO 2 absorption is limited by their slow absorption rates. Therefore, this study aims to synthesize mesoporous MgO nanoparticles through a simple method and utilize them to catalytically speed up the absorption of CO 2 in representative tertiary amine MDEA solutions. This study primarily employed five magnesium sources as precursors to produce MgO nanoparticles through calcination. Among these, the MgO derived from the Mg(OH) 2 precursor exhibited the most effective catalytic performance for CO 2 absorption in MDEA solutions. Compared to the noncatalytic test, MgO-MgH achieved a 302.2% increase in the CO 2 absorption rate and an 82.6% increase in absorption capacity. The superior CO 2 absorption efficiency of the MgO-MgH catalyst is mainly attributed to its abundant surface alkaline sites and oxygen vacancies. Online FT-IR characterization results evidenced the catalytic role of MgO-MgH in facilitating the CO 2 absorption process. A possible catalytic absorption mechanism over MgO-MgH is proposed. Moreover, the MgO-MgH’s stability was confirmed through a ten-cycle CO 2 absorption–desorption study. This study proposes a method to enhance CO 2 absorption by incorporating an easily synthesized alkaline nanomaterial, MgO-MgH, effectively overcoming its drawback and advancing the practical application of tertiary amine absorbents for CO 2 capture.