Taming structure and modulating carbon dioxide (CO) adsorption isosteric heat of nickel-based metal organic framework (MOF-74(Ni)) for remarkable CO capture.

Though the highest CO capture capacity belongs to liquid amine-solutions, solid matters capable of CO capture are also highly sought, providing that, they offer at least analogous CO adsorption capacity and CO/N selectivity. Herein, a surprisingly high-performance Ni-based metal-organic framework for CO adsorption, namely MOF-74(Ni), was synthesized by a facile condensation reflux approach. It was found that the structure and CO adsorption isosteric heat of MOF-74(Ni) could tune upon varying the synthesis duration under various temperatures. The optimized MOF-74(Ni)-24-140 (synthesized at 140 °C for 24 h) displays outstanding CO adsorption capacity of 8.29/6.61 mmol/g at 273/298 K under normal pressure of 1.0 bar, several times higher than previously reported MOF-74-Ni (2.0/2.1 times), UTSA-16 (1.5/1.6 times), and DA-CMP-1 (3.6/4.9 times) under similar conditions. The excellent CO capture capacity is associated to the abundant adsorption sites (mainly arising from the cationic Ni ions) and narrow micropore channels (mainly arising from the cage structure of Ni ions coordinated with organic linkers). Offering a high CO selectivity (CO/N = 49) and a well-tuned isosteric heat of CO adsorption (27-52 kJ/mol) besides its decent CO capture capacity, MOF-74(Ni) strongly stands out as an efficient and strong CO capturing material with industrial scale applicability.