Controlled formation of reactive Fe particles dispersed in a carbon matrix active for the oxidation of aqueous contaminants with H2O2

In this work, reactive iron nanoparticles dispersed in a carbon matrix were produced by the controlled thermal decomposition of Fe 3+ ions in sucrose. During the sucrose decomposition, the Fe 3+ ions are reduced to form iron nanometric cores dispersed in a porous carbonaceous matrix. The materials were prepared with iron contents of 1, 4, and 8 wt.% and heated at 400, 600, and 800 °C. Analyses by X-ray diffraction, Mössbauer spectroscopy, magnetization measurements, Raman spectroscopy, termogravimetric analyses, BET surface area, scanning, and transmission electron microscopy showed that at 400 °C, the materials are composed essentially of Fe 3 O 4 particles, while treatments at higher temperatures, i.e., 600 and 800 °C, produced phases such as Fe 0 and Fe 3 C. The composites were tested for the oxidation of methylene blue with H 2 O 2 by a Fenton-type reaction and also H 2 O 2 decomposition, showing better performance for the material containing 8 % of iron heated at 400 and 600 °C. These results are discussed in terms of Fe 2+ surface species in the Fe 3 O 4 nanoparticles active for the Fenton reaction.