Heterocycles for direct air capture and MOFs prepared from CO₂ utilization

The technology for carbon capture, utilization, and storage (CCUS) has drawn global attention because of the rapid climate changes. Herein, a series of nitrogen-rich heterocycles (HCx-N-y) was identified for direct air capture (DAC) based on a phase change mechanism. HCx-N-y possessed a CO2 removal efficiency of up to 99% under continuous CO2 flow with a concentration of 437 ppm via spontaneous CO2 fixation because it has a high CO2 sorption capacity of 23.82 mol kg(-1). Based on this phenomenon, a green and highly efficient strategy was discovered to utilize CO2 for different MOF syntheses via altering monomers and anions (SO42-, OAC(-), and NO3-). Furthermore, we made a novel discovery that anions significantly affect the topological structures and morphologies of MOFs. Hence, from the discovery of nitrogen-rich heterocycles (HCx-N-y) to direct air carbon capture to the synthesis of high value-added MOFs and then to the construction of high-performance gas separation membranes, this integrated strategy provided significant insights into the development of a comprehensive CCUS technology.