Porous liquids (PLs), as novel materials combining liquid fluidity with permanent porosity, demonstrate significant potential in gas capture and separation. However, the core challenge lies in achieving long-term stable dispersion of porous guests within sterically hindered solvents while maintaining pore accessibility. This work proposes a dual-functional layered double hydroxide (LDH) interfacial engineering strategy, successfully constructing stable porous SiO₂@LDH-based PLs. Cross-grown LDH nanosheets act as a physical barrier, effectively preventing steric solvent molecules from entering SiO₂ pores, thereby preserving abundant nanoscale cavities within the PL for CO₂ capture. Meanwhile, the abundant hydroxyl groups on LDH nanosheets form hydrogen bonds with the sterically hindered solvents, significantly enhancing the dispersion stability of the pore generators and preventing aggregation and sedimentation. The resulting PL exhibits outstanding long-term stability (>6 months without sedimentation) and highly efficient CO₂ capacity (1.51 mmol/g at 10 bar and 25 °C). Furthermore, this PL exhibits excellent selectivity (with a selectivity of 170 when simulating flue gas with a CO₂: N₂ ratio of 15%/85%) and cycle stability (retaining 97% of its maximum CO₂ capacity after 10 cycles). Isothermal adsorption models and adsorption kinetics models confirmed that the process primarily involves heterogeneous multilayer physical adsorption, thereby avoiding the capacity loss and energy consumption associated with regeneration caused by chemical absorption in traditional CO₂ absorption liquids. This study presents a novel and versatile interface design method for fabricating high-performance, stable PLs for CO₂ capture.

Metal–organic frameworks (MOFs) containing two different inorganic metal nodes (known as bimetallic MOFs) could exhibit enhanced CO₂ adsorption compared to their monometallic counterparts. Herein, a series of bimetallic NiCo-MOF-74 synthesized by microwave-assisted method were investigated for CO₂ adsorption. It was revealed that narrow micropore channel with open metal site (OMS) of the bimetallic NiCo-MOF-74 influence CO₂ binding affinity and CO₂/N₂ adsorption. The CO₂ uptake of Ni₁Co₁-MOF-74 at 0 ​℃ and 1 ​bar (100 ​kPa) was 8.30 ​mmol ​g⁻¹ which is higher than those of Ni-MOF-74 (3.99 ​mmol ​g⁻¹), Ni₆Co₁-MOF-74 (3.62 ​mmol ​g⁻¹), Ni₁Co₆-MOF-74 (6.40 ​mmol ​g⁻¹) and Co-MOF-74 (5.03 ​mmol ​g⁻¹). While this could be related to the high specific surface area of Ni₁Co₁-MOF-74, Ni₁CO₂-MOF-74 with relatively low specific surface areas still shows good CO₂ adsorption capacity up to 5.70 ​mmol/g, which is higher than those of adsorbents Ni-MOF-74, Ni₆Co₁-MOF-74 and Co-MOF-74, indicating that adsorption performance mainly relies on coordinated metals. Ni₁Co₁-MOF-74 showed remarkable recyclability performance, ranking selectivity of CO₂/N₂ reach up to 34, and suitable isosteric heat (31–23 ​kJ ​mol⁻¹), manifesting a great probability for industrial CO₂ capture. As revealed, incorporated Ni²⁺/Co²⁺ nodes within Ni₁Co₁-MOF-74, which are acting as active and open sites for CO₂ capture, led to the synergetic effects comprising of micropores as well as dense dual-metal sites.