Ultralow Parasitic Energy for Postcombustion CO₂ Capture Realized in a Nickel Isonicotinate Metal–Organic Framework with Excellent Moisture Stability

Metal-organic frameworks (MOFs) have attracted significant attention as solid sorbents in gas separation processes for low-energy postcombustion CO₂ capture. The parasitic energy (PE) has been put forward as a holistic parameter that measures how energy efficient (and therefore cost-effective) the CO₂ capture process will be using the material. In this work, we present a nickel isonicotinate based ultramicroporous MOF, 1 [Ni-(4PyC)₂·DMF], that has the lowest PE for postcombustion CO₂ capture reported to date. We calculate a PE of 655 kJ/kg CO₂, which is lower than that of the best performing material previously reported, Mg-MOF-74. Further, 1 exhibits exceptional hydrolytic stability with the CO₂ adsorption isotherm being unchanged following 7 days of steam-treatment (>85% RH) or 6 months of exposure to the atmosphere. The diffusion coefficient of CO₂ in 1 is also 2 orders of magnitude higher than in zeolites currently used in industrial scrubbers. Breakthrough experiments show that 1 only loses 7% of its maximum CO₂ capacity under humid conditions.