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In this research, the effects of pH, reaction temperature and holding reaction time on the synthesis of one-dimensional ZnWO 4 nanostructures by a hydrothermal method were studied. Phase, morphology and atomic vibration were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), and Fourier transform infrared (FTIR) and Raman spectroscopy. The pure monoclinic ZnWO 4 structure was synthesized at the pH solutions of 7 and 8. By varying the pH values, the mixtures of monoclinic ZnWO 4 and hexagonal ZnO as major and minor phases were detected at the pH 9 and 10 solutions, and the pure hexagonal ZnO phase at the pH 11 and 12. SEM and TEM images proved that ZnWO 4 nanorods grew along the [021] direction, with the reaction temperature and time to control their morphologies. The Zn-O, Zn-O-W, and W-O stretching vibrations were detected at 474, 888, and 726 cm À1 , and their corresponding bending vibrations at 430, 826, and 582 cm À1 , respectively. The optical properties of ZnWO 4 nanorods were also investigated by UV-visible (UV-vis) and photoluminescence (PL) spectroscopy. The above analyses proved that the appropriate condition for synthesizing of ZnWO 4 nanorods is at pH 8 by the 200 C and 24 h hydrothermal treatment.

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Orthorhombic α-MoO3microplates were produced from (NH4)6Mo7O24·4H2O solid powder by a 900 W microwave plasma for 40, 50, and 60 min. Phase, morphologies, and vibration modes were characterized by X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and Raman and Fourier transform infrared (FTIR) spectroscopy. Sixty min processing resulted in the best crystallization of the α-MoO3phase, with photoluminescence (PL) in a wavelength range of 430–440 nm.

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