Vapor phase synthesis of metal–organic frameworks on a nanofibrous aerogel creates enhanced functionality

Abstract

This study introduces an innovative approach for synthesizing metal–organic frameworks (MOFs) on 3D-structured hierarchically porous nanofibrous aerogels (NFAs). The NFA was initially fabricated by solid-templating cellulose diacetate (CDA)–silica electrospun nanofibers and subsequently coated with ZIF-8 MOF via vapor phase synthesis. The ZIF-8 MOF – known for its CO₂ adsorption, heavy metal removal, and antibacterial properties – was synthesized directly on the NFA, producing a uniform layer of densely packed ZIF-8 crystals on the CDA–silica nanofibers. The integrated MOF–NFA features a rich functional diversity. First, measurements of mechanical compressibility demonstrated the robustness and strain recovery of the CDA–silica@ZIF-8 NFAs, and thus their applicability in environments that entail exposure to mechanical stress. Furthermore, the ZIF-8-coated aerogel, with its high CO₂ adsorption rate and capacity (4.04 mmol g⁻¹), holds promise as a substrate for CO₂ separation or sequestration. The aerogel also exhibits excellent performance in removing heavy metals, particularly Cu(II) ions (>99% removal). The high adsorption capacity is rooted in the thin and uniform ZIF-8 coating of the NFA, and grants applicability for water purification. The antibacterial properties of the hybrid aerogel demonstrate efficacy against both Gram-negative and Gram-positive bacteria. In summary, the hybrid NFA shows promise for various applications, particularly in tackling challenges in environmental and biomedical fields, encompassing sorption, catalysis, filtration, water purification, and antimicrobial applications.