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

In this study, a composite material composed of Mg-MOF-74 and graphene oxide (GO) was synthesized to overcome MOFs’ limitations in CO₂ capture. At 273 K/101 kPa, the Mg-MOF-74 composite containing 6 wt% GO achieved 3.46 mmol/g CO₂ uptake and 114.4 CO₂/N₂ selectivity, demonstrating 25.8 % and 29.3 % enhancements compared with pristine Mg-MOF-74. This enhancement is due to the optimization of CO₂ adsorption by the new pores formed at the interface and the strong affinity of GO functional groups for CO₂ 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 CO₂ 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[dbnd]O bonds in urea can boost adsorption/separation and enhance stability through amine-Mg²⁺ coordination. These findings highlight Mg-MOF-74@GO composites as promising candidates for industrial CO₂ capture.