Rapid synthesis of magnetic microspheres and the development of new macro-micro hierarchically porous magnetic framework composites

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-07, Vol.11 (27), p.1475-14719
• Main Authors: Woodliffe, John Luke, Molinar-Díaz, Jesús, Islam, Md Towhidul, Stevens, Lee A, Wadge, Matthew D, Rance, Graham A, Ferrari, Rebecca, Ahmed, Ifty, Laybourn, Andrea
• Format: Article
• Language: English
• Subjects: Adaptability; Calcium oxide; Composite materials; Copper; Induction heating; Lime; Magnetic materials; Magnetism; Metal-organic frameworks; Microspheres; Polymer coatings; Porosity; Porous materials; Spheroidizing; Synthesis
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta01927f

Magnetic framework composites (MFCs) are a highly interesting group of materials that contain both metal-organic frameworks (MOFs) and magnetic materials. Combining the unique benefits of MOFs (tuneable natures, high surface areas) with the advantages of magnetism (ease of separation and detection, release of guests by induction heating), MFCs have become an attractive area of research with many promising applications. This work describes the rapid, scalable synthesis of highly porous magnetic microspheres via a flame-spheroidisation method, producing spheres with particle and pore diameters of 206 ± 38 μm and 12.4 ± 13.4 μm, respectively, with a very high intraparticle porosity of 95%. The MFCs produced contained three main iron/calcium oxide crystal phases and showed strong magnetisation ( M s : 25 emu g −1 ) and induction heating capabilities ( 80 °C rise over 30 s at 120 W). The microspheres were subsequently surface functionalised with molecular and polymeric coatings (0.7-1.2 wt% loading) to provide a platform for the growth of MOFs HKUST-1 and SIFSIX-3-Cu (10-11 wt% loading, 36-61 wt% surface coverage), producing macro-micro hierarchically porous MFCs (pores > 1 μm and