Optimizing doped graphene oxide in Mg-MOF-74 to enhance its stability and CO2 adsorption and separation performance

• Adsorption performance and structural stability of Mg-MOF-74@GO composite were markedly improved vs. pristine Mg-MOF-74. • Urea-modified GO incorporation further enhances both adsorption capacity and structural stability of the composite. • The interaction mechanism between GO and Mg-MOF-74 was elaborated, and the composite’s adsorption mechanism explained. • The reasons for the improvement of the composite’s adsorption performance and stability were elaborated. In this study, a composite material composed of Mg-MOF-74 and graphene oxide (GO) was synthesized to overcome MOFs’ limitations in CO 2 capture. At 273 K/101 kPa, the Mg-MOF-74 composite containing 6 wt% GO achieved 3.46 mmol/g CO 2 uptake and 114.4 CO 2 /N 2 selectivity, demonstrating 25.8 % and 29.3 % enhancements compared with pristine Mg-MOF-74. This enhancement is due to the optimization of CO 2 adsorption by the new pores formed at the interface and the strong affinity of GO functional groups for CO 2 molecules. Furthermore, due to the excellent properties of GO and its strong interaction with Mg-MOF-74, the composites show notable improvements in thermal, adsorption–desorption cycling, and moisture stability. Notably, the Mg-MOF-74 composite containing 6 wt% urea-modified GO exhibits optimal CO 2 adsorption/stability. This is not only due to the synergy between GO and Mg-MOF-74, but also because the amine groups and polar C O bonds in urea can boost adsorption/separation and enhance stability through amine-Mg 2+ coordination. These findings highlight Mg-MOF-74@GO composites as promising candidates for industrial CO 2 capture.