Combined CO₂-philicity and Ordered Mesoporosity for Highly Selective CO₂ Capture at High Temperatures

Various dry sorbents have been lately introduced as promising media to capture carbon dioxide (CO₂). However, it is still desirable to further improve their performance in diverse aspects, and high temperature selectivity of CO₂ over other gases is clearly one of them. Here, we report a co-assembly approach to turn nonporous melamine resin to a highly ordered mesoporous polymeric network (space group: Im3¯m) containing high nitrogen content (∼18 at%). This mesoporous network shows anomalously increasing CO₂/N₂ selectivity with temperature rise, with the selectivity at 323 K reaching 117 (Henry method). This selectivity behavior is attributed to a combined effect of the high nitrogen content allowing for high binding affinity with CO₂ and well-defined mesopores (2.5-2.9 nm) accelerating release of N₂ with temperature rise. The given orthogonal approach suggests a new direction in designing dry sorbents with excellent selectivities at high temperatures. (Graph Presented).