New soft chemistry route to titanomagnetite magnetic nanoparticles with enhanced peroxidase-like activity

Titanomagnetite is widely distributed in nature, and has potentials in environmental remediation. Nanometric titanomagnetite particles were usually prepared via soft chemistry routes in aqueous solutions. Herein a novel soft chemistry route carried out in a deep eutectic solvent (DES) comprising choline chloride and urea in a molar ratio of 1:2 was successfully developed to make titanomagnetite nanoparticles (Fe2.5Ti0.5O4-DES, similar to 30 nm). The chemical composition analyzed by different methods revealed that Fe2.5Ti0.5O4-DES nanoparticles possess the Ti-rich core and Fe-rich shell. The Fe2.5Ti0.5O4-DES nanoparticles exhibited enhanced activities in catalytic decomposition of H2O2 and oxidative degradation of organic contaminants at circumneutral pH values and room temperature, which was mainly attributed to the increased content of ferrous (Fe2+) ions upon substitution of Ti4+ for ferric (Fe3+) ions in spine! structure of magnetite. (C) 2020 Elsevier B.V. All rights reserved.