Fluorescent Microporous Polyimides Based on Perylene and Triazine for Highly CO₂-Selective Carbon Materials

Carbon dioxide (CO2) capture from point sources like coal-fired power plants is a potential solution for stabilizing atmospheric CO2 content to avoid global warming. Sorbents with high and reversible CO2 uptake, high CO2 selectivity, good chemical and thermal stability, and low cost are desired for the separation of CO2 from N2 in flue or natural gas. We report here, for the first time, on the synthesis of new microporous polyimide (PI) networks from the condensation of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and 1,3,5-triazine-2,4,6-triamine (melamine) using a Lewis acid catalyst zinc acetate/imidazole complex. These PI network materials, prepared in the absence and presence of dimethyl sulfoxide (DMSO) as weak solvent template, exhibit strong fluorescence. Nitrogen-containing carbons can be accessed from our PI networks via a simple thermal pyrolysis route. The successful construction of new microporous PI networks and derived N-containing carbons is shown here to provide promising CO2 sorbents with high uptake capacities (15 wt %) combined with exceptional selectivities over N2 (240), while their fluorescent properties can be exploited for simple sensing.