Porous covalent electron-rich organonitridic frameworks as highly selective sorbents for methane and carbon dioxide

Carbon dioxide capture from point sources like coal-fired power plants is considered to be a solution for stabilizing the CO2 level in the atmosphere to avoid global warming. Methane is an important energy source that is often highly diluted by nitrogen in natural gas. For the separation of CO2 and CH4 from N2 in flue gas and natural gas, respectively, sorbents with high and reversible gas uptake, high gas selectivity, good chemical and thermal stability, and low cost are desired. Here we report the synthesis and CO2, CH4, and N2 adsorption properties of hierarchically porous electron-rich covalent organonitridic frameworks (PECONFs). These were prepared by simple condensation reactions between inexpensive, commercially available nitridic and electron-rich aromatic building units. The PECONF materials exhibit high and reversible CO2 and CH4 uptake and exceptional selectivities of these gases over N2. The materials do not oxidize in air up to temperature of 400 °C.