A porous Mg<inf>2</inf>(dondc) framework (H<inf>4</inf>dondc = 1,5-dioxido-2,6-naphthalenedicarboxylic acid) with open metal sites was prepared and functionalized with primary or secondary diamines (en = ethylenediamine, mmen = N,N′-dimethylethylenediamine, or ppz = piperazine). The CO<inf>2</inf> adsorption was substantial under post-combustion flue gas conditions as compared to other reported metal-organic frameworks. Interestingly, the IR spectroscopic measurements demonstrated that the CO<inf>2</inf> adsorption mechanism is based on the combination of physisorption and chemisorption. The CO<inf>2</inf> adsorption capacity of 1-mmen was greater than that of 1-en and 1-ppz, which can likely be attributed to the basicity of the free amine groups tethered to the open coordination sites. Ultrahigh selectivity and superior dynamic separation of CO<inf>2</inf> over N<inf>2</inf> were evident in 1-ppz. Such exceptional CO<inf>2</inf> uptake and CO<inf>2</inf>/N<inf>2</inf> selectivity of diamine-functionalized materials hold potential promise for post-combustion CO<inf>2</inf> capture applications.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)