One-step synthesis of SiO2 alpha-Fe2O3 / Fe3O4 composite nanoparticles with magnetic properties from rice husks

This paper presents different methodologies for the preparation of Fe2O3@SiO2 nanoparticles (composites) and their characterization. The composite nanoparticles were prepared directly from rice husks. Two methodologies were used, (i) impregnation with an ionic iron solution of rice husks followed with a thermal treatment and (ii) impregnation of the pre-calcinated and lixiviated rice husks. In both methods, a low density, homogenous and highly porous SiO2 nanoparticles with a mean diameter of 20 nm and loaded with different types of iron oxide are generated. The synthetized products were systematically characterized by SEM, AFM, DLS, FT-IR, Mossbauer and VSM. The results show that two different composites were obtained, one mostly composed by alpha-Fe2O3@SiO2 and a second one mostly composed by gamma-Fe2O3@SiO2. Mossbauer and VMS spectra show that iron oxide nanoparticles are formed in the pores of the SiO2 nanoparticles and the first method promote production of composites with magnetic properties. These results highlight a new one-step methodology to obtain silica nanoparticles loaded with iron oxides and with high magnetic properties.

Automated summary

This study presents different methodologies for preparing Fe2O3@SiO2 nanoparticles and characterizing them. A new one-step method to obtain silica nanoparticles loaded with iron oxides and with high magnetic properties was highlighted.