Harnessing the Hybridization of a Metal‐Organic Framework and Superbase‐Derived Ionic Liquid for High‐Performance Direct Air Capture of CO₂

Abstract

Direct air capture (DAC) of CO2 has emerged as the most promising “negative carbon emission” technologies. Despite being state‐of‐the‐art, sorbents deploying alkali hydroxides/amine solutions or amine‐modified materials still suffer from unsolved high energy consumption and stability issues. In this work, composite sorbents are crafted by hybridizing a robust metal‐organic framework (Ni‐MOF) with superbase‐derived ionic liquid (SIL), possessing well maintained crystallinity and chemical structures. The low‐pressure (0.4 mbar) volumetric CO2 capture assessment and a fixed‐bed breakthrough examination with 400 ppm CO2 gas flow reveal high‐performance DAC of CO2 (CO2 uptake capacity of up to 0.58 mmol g−1 at 298 K) and exceptional cycling stability. Operando spectroscopy analysis reveals the rapid (400 ppm) CO2 capture kinetics and energy‐efficient/fast CO2 releasing behaviors. The theoretical calculation and small‐angle X‐ray scattering demonstrate that the confinement effect of the MOF cavity enhances the interaction strength of reactive sites in SIL with CO2, indicating great efficacy of the hybridization. The achievements in this study showcase the exceptional capabilities of SIL‐derived sorbents in carbon capture from ambient air in terms of rapid carbon capture kinetics, facile CO2 releasing, and good cycling performance.

Facile grinding method synthesis of SnS2@HKUST-1 and SnS2@Ni-MOF for electrocatalytic hydrogen evolution

“…SnS 2 , as a binary analog of graphene, has a large number of active sites due to its unique crystal arrangement, which is distributed in a layered structure, so it can expose a relatively large number of active sites and has a large specific surface area. 58 All these four samples show a relatively regular hexagonal structure. Among them, the hexagonal sheet structure of the S8 sample is more obvious and evenly arranged, which improves the specific surface area of the material and provides more active sites.…”

“…In SAXS, the position of the SnS 2 @Ni-MOF peak is unchanged compared to the Ni-MOF peak, but the slight increase in peak intensity is due to the fact that the 2D MOFs complexed with SnS 2 can form a complex with an inserted structure, which increases the pore size of the complex. 58 As shown in Table S4 (ESI†), the concentrations of S in 0.5 M H 2 SO 4 of Ni-MOF and SnS 2 @Ni-MOF before and after the stability tests were 15 726 mg L −1 and 15 292 mg L −1 , respectively, and Sn and Ni were not detected. These results indicate that the synthesized Ni-MOF and SnS 2 @Ni-MOF are stably present in the sulfuric acid electrolyte and show stable electrocatalytic activity.…”

From Lab to Fab: Development and Deployment of Direct Air Capture of CO2

“…Moitra et al [43] used CaO-and superbase-ionic liquids (SIL)-bifunctionalized sorbents to capture CO 2 ; these sorbents demonstrated rapid interaction kinetics, high CO 2 uptake capacity, facile CO 2 release, and stable sorption/desorption cycles. New research proposes that immobilizing ILs in porous materials with large surface areas and specific active sites, such as MOFs, might remedy the difficulties caused by ILs [44][45][46], which is discussed further in the MOF part under Section 2.2.…”

Minimal Kinetic Model of Direct Air Capture of CO2 by Supported Amine Sorbents in Dry and Humid Conditions

“…2,23−25 Moreover, other chemisorption systems using superbase-derived ionic liquids have been developed. 26,27 Although researchers have turned their attention to DAC conditions, 8,28,29 how sorbent properties and H 2 O affect CO 2 adsorption at DAC conditions is not well understood from a modeling perspective. 30−32 On the experimental side, Sayari, 33 Jones, 1 and many others have extensively examined aminefunctionalized mesoporous silica for DAC.…”

“…The dilute concentration of CO 2 in ambient air at about 400 ppm is one major challenge for DAC, requiring a strong thermodynamic driving force for its sorption. Most of the experimental and modeling work on amines focused on much higher CO 2 partial pressures. ,− Enhanced CO 2 adsorption in the presence of H 2 O has been widely observed in amine adsorbents. ,− Moreover, other chemisorption systems using superbase-derived ionic liquids have been developed. , Although researchers have turned their attention to DAC conditions, ,, how sorbent properties and H 2 O affect CO 2 adsorption at DAC conditions is not well understood from a modeling perspective. − On the experimental side, Sayari, Jones, and many others have extensively examined amine-functionalized mesoporous silica for DAC. The effect of water on CO 2 adsorption has been recently reviewed by Sayari and co-workers, while Jones and co-workers have investigated many different types of porous supports loaded with poly­(ethylenimine) (PEI). , Molecular simulations at both the molecular mechanical and quantum mechanical levels have been employed to understand the DAC of CO 2 and its interaction and reaction with amines as well. − …”