Size-Controlled Synthesis of Magnetite (Fe3O4) Nanoparticles Coated with Glucose and Gluconic Acid from a Single Fe(III) Precursor by a Sucrose Bifunctional Hydrothermal Method

Size-controlled and coated magnetite nanoparticles with glucose and gluconic acid have been successfully synthesized via a simple and facile hydrothermal reduction route using a single iron precursor, FeCl3, and a combination of the inherent chemical reduction capability of sucrose decomposition products and their inorganic coordinating ability. The particle size can be easily controlled in the range of 4−16 nm. Results obtained with and without the addition of sucrose indicate that sucrose is required for the formation of nanoscale and coated magnetite instead of the much larger hematite. Mass spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetry analysis were used to investigate the formation mechanism of the coated nanomagnetite from the single Fe(III) precursor in sucrose. Sucrose acts as a bifunctional agent: (i) it decomposes into reducing species, causing partial reduction of the Fe3+ions to Fe2+ions as required for the formation of Fe3O4and (ii) acts as the source of a capping agent to adjust the surface properties and enable the formation of nanoscale particles. The saturation magnetization of the as-obtained magnetite is measured and greatly related to the particle size.