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Three kinds of polyhedral α‐Fe2O3 nanoparticles enclosed by different facets including oblique parallel hexahedrons (op‐hexahedral NPs), cracked oblique parallel hexahedrons (cop‐hexahedral NPs), and octadecahedral nanoparticles (octadecahedral NPs), were successfully prepared by simply changing only one reaction parameter in the hydrothermal process. The structural and morphological of the products were systematically studied using various characterizations including X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), revealing that the three kinds of α‐Fe2O3 nanoparticles were enclosed by {104}, {110}/{104}, and {102}/{012}/{104} crystal planes, respectively. The exposed facets and shape of the nanocrystals were found to be affected by the adding amount of ethylene glycol in the solvent. The gas‐sensing properties and mechanism of the α‐Fe2O3 samples were studied and analyzed, which indicated that the sensitivity of the three samples followed the order of octadecahedral NPs > cop‐hexahedral NPs > op‐hexahedral NPs due to the combined effects of specific surface area and oxygen defects in the nanocrystals. [ABSTRACT FROM AUTHOR]

Three different Cu2O nanostructures, namely porous nanospheres, nanoparticles, and nanocubes, were synthesized through a facile solution route at room temperature. Structure and morphology of the products were characterized by X-ray diffraction ( XRD), transmission electron microscopy ( TEM), field-emission scanning electron microscopy ( FESEM), and nitrogen adsorption-desorption isotherms. The adsorption behavior of Methyl Orange ( MO) onto these Cu2O nanostructures was investigated, considering the effect of initial methyl orange concentration and the additive amount of Cu2O products. The kinetic and equilibrium investigations suggested that the adsorption process of MO followed a pseudo-second order rate equation and the Langmuir isotherm model. The maximum adsorption capacity of the three samples followed the sequence: porous nanospheres > nanoparticles > nanocubes, which was in accordance of the BET specific surface of the samples. In addition, further investigations indicated that the as-prepared Cu2O nanostructures also show good adsorption properties for other anionic dyes including Congo red and Methyl blue. [ABSTRACT FROM AUTHOR]

Uniform ZnO nanospheres have been successfully synthesized through a facile solvothermal process. The structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the products were ZnO nanospheres of 300–350 nm in diameter, which were composed of nanoparticles of ca. 5–10 nm. The size of the nanospheres can be tuned from ca. 300 nm to 1 μm by changing the concentration of the reactants. The gas sensing performance of the ZnO nanospheres with different size were investigated, which indicated that the ZnO nanospheres exhibited good gas sensitivity and selectivity towards n-butanol. In addition, the gas sensitivity of the ZnO nanospheres exhibited obvious size-dependent effect. [ABSTRACT FROM AUTHOR]

Abstract: Uniform hematite nanoparticles have been successfully synthesized through a surfactant mediated hydrothermal method. The structure and morphology of the products were characterized by powder X-ray diffraction, transmission electron microscope, scanning electron microscope, and Fourier transform infrared spectrometer. The results showed that the products were α-Fe2O3 nanoellipsoids of 115–140nm in long axis and 60–80nm in short axis. The growth mechanism of the products was proposed based on the experiments. Uniform nanospindles, nanoellipsoids, nanospheres, and nanopolyhedra with different sizes can be obtained by adjusting the reaction temperature, the amount of additive, and concentration of the reactants. The result may facilitate the exploration of controlled synthesis of α-Fe2O3 nanoparticles. [Copyright &y& Elsevier]

Abstract: Single-crystal cuprous iodide semiconductor nanospheres were fabricated via a mild low-temperature solution route by using polyvinyl pyrrolidone as capping agent and the mixture of water and polyethylene glycol 400 as solvent. The structure, morphology, and properties of the products were characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal gravimetry and photoluminescence spectrometry. The results showed that the products were CuI nanospheres of ca. 280–650nm in diameter and were composed of quasi-trigonal particles of ca. 20–40nm. The phase transformation temperature and the melting point of the products decreased by ca. 12 and 8°C compared with the bulk CuI. The possible formation mechanism was discussed on the basis of experimental results. [Copyright &y& Elsevier]