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Abstract: The electrical, optical, and adsorption properties of akaganeite (β-FeOOH) can be modified by doping or combining with variety of elements. We prepared metal ions (Sn, Zn) doped β-FeOOH using β-FeOOH nanorods as the precursor by the hydrothermal method and investigated the effect of metal ions (Sn, Zn) on the thermal property of β-FeOOH nanorods. The doping of metal ions (Sn, Zn) was confirmed by X-ray powder diffraction, energy dispersive spectroscopy, and atomic emission spectrometer analysis. Thermogravimetric analysis and differential thermal analysis showed that they have different thermal decomposition temperatures. β-FeOOH nanorods and Zn doped β-FeOOH nanorods were transformed into α-Fe2O3 particles at 400°C. While Sn doped β-FeOOH nanorods should be heated to higher temperature (600°C). Sn doped β-FeOOH nanorods showed higher thermal stability due to the Sn ions binding with the framework of β-FeOOH. Both Sn and Zn ions doped β-FeOOH remained the rod like shape. [Copyright &y& Elsevier]

Abstract: Hematite hollow cubes have been prepared by forced hydrolysis of ferric chloride solutions under hydrothermal conditions. The effects of reaction time, reaction temperature and cetyltrimethyl ammonium bromide on the transformation process from akageneite to hematite were investigated in detail. The products were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. It is found that cetyltrimethyl ammonium bromide was a critical factor influencing the phase transformation process of akageneite and the final morphology of the as-prepared products. With cetyltrimethyl ammonium bromide, hematite hollow cubes and porous spheres were obtained. Otherwise only dense cubes were observed even prolonging reaction time or increasing reaction temperature. The mechanism was proposed. [ABSTRACT FROM AUTHOR]

Abstract: Sn doped Fe3O4/SiO2 core–shell structures with the magnetic and photocatalytic properties have been successfully synthesized using Fe3O4 microspheres as the precursor. The morphology, phase and structure of the bifunctional products were investigated by X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy. The effects of the amount and hydrolysis rate of tetraethyl orthosilicate on the preparation of the Fe3O4/SiO2 core–shell structures were investigated. Low concentration and slow hydrolysis rate of tetraethyl orthosilicate were useful to obtain the uniform silica coated Fe3O4. The magnetic measurements indicated that the Sn doped Fe3O4/SiO2 core–shell structures showed ferromagnetic property and the magnetic saturation value slightly decreased after coated the silica layer. The magnetic Sn doped Fe3O4/SiO2 core–shell structures exhibited good photocatalytic activity in the degradation of methyl orange and could be separated by applying an appropriate magnetic field. [Copyright &y& Elsevier]

Abstract: In this paper, we reported a simple solution method to assemble SnO2 nanorods hierarchically on the surface of α-Fe2O3 nanosheets using Fe3O4 nanosheets as precursor. The product was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Our experimental results show that the lattice mismatch at the interface of SnO2 nanorods with α-Fe2O3 nanosheets played an important role in determining the growth direction of SnO2 nanorods. The interface prefers to take the least lattice mismatch and thus the preferential growth direction of SnO2 nanorods was along [101] direction. The result may have important impact on the understanding of the nucleation growth process in a heterogeneous system. [Copyright &y& Elsevier]

Abstract: Cobalt oxalate nanorods have been successfully synthesized by a simple microwave-assisted solution approach using an ionic liquid 1-n-butyl-3-methyl imidazolium tetrafluoroborate. Upon thermal decomposition at 400°C, cobalt oxalate nanorods could be converted to Co3O4 rods consisting of nanoparticles. The products were characterized using X-ray powder diffraction, transmission electron microscopy, thermogravimetric analysis and differential scanning calorimetric analysis. [Copyright &y& Elsevier]