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We report a general reaction container effect in the nanocasting synthesis of mesoporous metal oxides. The size and shape of the container body in conjunction with simply modifying the container opening accessibility can be used to control the escape rate of water and other gas-phase byproducts in the calcination process, and subsequently affect the nanocrystal growth of the materials inside the mesopore space of the template. In this way, the particle size, mesostructure ordering, and crystallinity of the final product can be systemically controlled. The container effect also explain some of the problems with reproducibility in previously reported results.

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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, FeCl 3 , 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 Fe 3+ ions to Fe 2+ ions as required for the formation of Fe 3 O 4 and (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 asobtained magnetite is measured and greatly related to the particle size.