Electromagnetic one-pot fabrication of flexible monolithic catalysts with boosted oxygen vacancies for enhanced VOCs oxidation

Practical purification devices for the complete degradation of volatile organic compounds (VOCs) in industrial exhaust gases typically employ monolithic catalysts due to their advantages in reducing gas resistance and enhancing efficiency. Fe cotton serves as a potential support material for such catalysts owing to its excellent thermal conductivity and the inherent flexibility of its velvet structure. Its superior thermal conductivity ensures uniform heat distribution during catalytic reactions. At the same time, the unique velvet architecture facilitates the homogeneous loading of active components on the surface and significantly reduces the risk of active component detachment. To fully leverage these advantages, this study introduces an electromagnetic induction dry quenching (EMIQ) technique that in-situ loads non-noble metal active sites onto Fe cotton via Joule heating induced by a high-frequency magnetic field. This universal method compresses the catalyst synthesis cycle from days to minutes and precisely controls the dispersion state and loading of active species (e.g., Co 3 O 4 nanoparticles) by tuning the precursor concentration (e.g., 0.05–0.20 mol/L Co solution) and quenching cycles (1–4 times). The optimized 0.10-Co/Fe-2 catalyst achieves a 50 % toluene conversion at 300 °C under traditional resistance heating, with excellent stability. Characterization results reveal that the rapid heating process induced by electromagnetic induction dry quenching (EMIQ) promotes the formation of defect structures (e.g., oxygen vacancies) on the material surface and strengthens the electronic metal-support interaction (EMSI) between Co and Fe, significantly enhancing the redox activity and oxygen adsorption capacity of the catalyst. This work provides a new strategy for the scalable preparation of high-performance VOCs degradation catalysts.