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

Woodliffe, John Luke; Molinar-Díaz, Jesús; Islam, Md Towhidul; Stevens, Lee A.; Wadge, Matthew D.; Rance, Graham A.; Ferrari, Rebecca; Ahmed, Ifty; Laybourn, Andrea

Abstract

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 (Ms: 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 <10 nm). To the best of our knowledge, these are the first example of MFCs using a single-material porous magnetic scaffold. The adaptability of our synthetic approach to novel MFCs is applicable to a variety of different MOFs, providing a route to a wide range of possible MOF–microsphere combinations with diverse properties and subsequent applications.

Citation

Woodliffe, J. L., Molinar-Díaz, J., Islam, M. T., Stevens, L. A., Wadge, M. D., Rance, G. A., Ferrari, R., Ahmed, I., & Laybourn, A. (2023). Rapid synthesis of magnetic microspheres and the development of new macro-micro hierarchically porous magnetic framework composites. Journal of Materials Chemistry A, 11(27), 14705-14719. https://doi.org/10.1039/D3TA01927F

• Journal Article Type: Article
• Acceptance Date: May 30, 2023
• Online Publication Date: May 30, 2023
• Publication Date: Jul 21, 2023
• Deposit Date: Jun 16, 2023
• Publicly Available Date: Jun 16, 2023
• Journal: Journal of Materials Chemistry A
• Print ISSN: 2050-7488
• Electronic ISSN: 2050-7496
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 27
• Pages: 14705-14719
• DOI: https://doi.org/10.1039/D3TA01927F
• Keywords: General Materials Science; Renewable Energy, Sustainability and the Environment; General Chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/21645889
• Publisher URL: https://pubs.rsc.org/en/Content/ArticleLanding/2023/TA/D3TA01927F