Preparation of covalent triazine frameworks with imidazolium cations embedded in basic sites and their application for CO2 capture

Functionalized covalent triazine frameworks (CTFs) realized by rational design of the monomer have been recognized as a promising candidate to achieve improvements in various applications. Here, new CTFs, 1,3-bis(pyridyl) imidazolium-based CTFs (bpim-CTFs), have been prepared via incorporation of an imidazolium motif into the monomer, which resulted in high functionalization of the frameworks. The bpim-CTFs showed N-rich environments, excellent micro-porosity (up to 1550 m2 g-1) and high thermal stabilities, promising for efficient CO2 capture. The bpim-CTF-500 showed the highest CO2 uptake capacity of up to 2.77 mmol at 1 bar at a temperature of 298 K, which is higher than those of most of the other POFs except a few examples. Additionally, the frameworks featured moderate CO2 selectivity over N2 up to 32.