Rapid Synthesis of MOF CaBTC using an ultrasonic irradiation method and its derivative materials for CO2 capture

Ca-based MOFs and related derived materials offer promising potential for CO2 capture. In this study, we synthesized a CaBTC MOF and polydopamine coated MOF composite by using an ultrasonic irradiation method, and a corresponding derivate was obtained by thermal treatment. The capacity of CO2 capture and subsequent adsorption performance from the resulting CaBTC MOF/MOF derivate under different temperatures were investigated in detail. The structural features and textural parameters of the obtained absorbents were assessed by XRD, SEM, EDS, FT-IR spectroscopy, Raman spectroscopy, XPS, TG-DSC, and N2 absorption/desorption characterization. The results demonstrated that the prepared of CaO/CN-x with basic functional groups exhibited micro/mesoporosity derived from organic matter removal through carbonization at 800°C. Both of these properties accounted for the highest CO2 capacity of 2.30 mmol/g at 273 K using pure CO2 for the CaO/CN-5 sample. Additionally, we found that the derivate of CaBTC MOF at high temperatures experienced two stages of chemical adsorption, as well as carbonation reaction. The high CO2 capture capacity reached 60.2 mass% in 10 min at 873 K for the CaO sample. Furthermore, the introduction of carbon components derived from organic matter in the CaBTC MOF derivate matrix promoted the conversion of CO2 to CO through the reduction reaction. Possible reaction mechanisms for the conversion of CO2 to CO were preliminary proposed based on thermodynamic calculation.