Heterocycles for direct air capture and MOFs prepared from CO2 utilization†

Abstract

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–Ny) was identified for direct air capture (DAC) based on a phase change mechanism. HCx–Ny 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–Ny) 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.