Functionalised modified metal–organic framework materials for CO₂ capture and separation

The strategic development of lithium-engineered metal–organic frameworks (MOFs) for high-performance CO₂ capture represents a critical pathway toward achieving net-zero emissions. Herein, we report three novel 2D copper-based MOFs coordinated with planar π-conjugated ligands, followed by targeted –OLi functionalisation via post-synthetic modification. –OLi groups induce electrostatic polarisation through Li→O charge transfer, creating strong Li–CO₂ interactions and spatial confinement via optimised pore geometry. The functionalised 2DMOF_n-OLi systems demonstrate exceptional CO₂ uptake capacities of 3.30–5.68 mmol·g⁻¹ at 298 K/1.0 bar, with record CO₂/N₂ and CO₂/CH₄ selectivities reaching 15,456.5 and 7239.9 respectively, surpassing benchmark materials (e.g. Mg-MOF-74: 4.21 mmol·g⁻¹). This dual-modification strategy (electronic structure engineering and pore geometry control) establishes a universal design paradigm for developing advanced sorbents, with demonstrated potential for direct air capture applications. To mitigate atmospheric CO₂ concentrations, three metal–organic frameworks were designed and functionalised by doping with –OLi functional groups, showing ultra-high CO₂ capture and separation.