Magnetothermally responsive composite submicron particles for recyclable catalytic applications

Magnetothermally responsive composite submicron particles, which combining rapid magnetic separation and magnetothermally responsive release, were developed for recycling of both loadings and carriers. [Display omitted] •Catalyst immobilized magnetothermally responsive particles are developed.•A novel strategy for recycling both the loadings and the carriers is proposed.•Recycling is achieved by magnetic separation and magnetothermally responsive.•Those particles possess high recycling efficiency and recycling times. To improve the recycling efficiency of magnetic recycling system, magnetothermally responsive composite submicron particles (CFMNs@PEG CSPs) were designed and prepared for recyclable catalytic applications, in which poly(ethylene glycol) gel was used as the shell and clusters of cobalt ferrite magnetic nanoparticles as the core. A novel strategy for recycling both loadings and carriers was proposed based on loadings immobilized CFMNs@PEG CSPs via magnetic separation at first and then magnetothermally responsive release. The morphology and core–shell structure were observed by transmission electron microscope. The physicochemical characteristics were investigated by Fourier transform infrared, 1H NMR, Magnetic property measurement system, thermogravimetric analysis and X-ray photoelectron spectroscopy. The size of CFMNs@PEG CSPs was 285.1 ± 7.6 nm (the core was 160.0 ± 13.2 nm and PEG gel shell was 62.6 nm). The shell thickness of CFMNs@PEG CSPs shrunk from 62.6 nm to 35.5 nm when the temperature changed from 25 °C to 50 °C, and more than 95% of the loadings were released in 30 min by magnetothermally responsive release. Combing magnetic separation and magnetothermally responsive release, CFMNs@PEG CSPs were recycled over 42 times for horseradish peroxidase catalysis (horseradish peroxidase was re-immobilized for six times and reused seven times for each re-immobilization) and 25 times for gold nanoparticles catalysis (reactivated gold nanoparticles were re-immobilized for five times and reused five times for each re-immobilization) without significant catalytic activity loss, indicating their extensive potential in recyclable catalytic applications and other applications.