Hydrothermal synthesis of hexagonal WO3 nanowires with high aspect ratio and their electrochemical properties for lithium-ion batteries

One dimensional WO₃ nanowires with high aspect ratio of >200 were synthesized by hydrothermal method. The effects of reaction temperature and time on phase and morphologies were studied and discussed. In this research, a suitable hydrothermal condition is at 200°C for 48 h. XRD, SEM, and TEM results show that the product is hexagonal WO₃ phase with diameter of 25 nm and several ten micrometers long with growth in the c direction. The electrochemical properties were tested for rechargeable lithium batteries. The WO₃ NWs electrode exhibits a stability trend over the 30 cycle testing. Some long-term activation process is attributed to the WO₃ NWs electrode during charge/discharge reaction.

     

Photocatalytic activity of ZNO with different morphologies synthesized by a sonochemical method

Different morphologies of ZnO structures were successfully synthesized in precursor solutions with the pH of 8, 9, 10, 11, and 12 by a sonochemical method at room temperature. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) and Raman spectroscopy. The photocatalytic activities of ZnO samples with different morphologies were evaluated via the degradation of methylene blue (C₁₆H₁₈ClN₃S). In this research, the flower-like ZnO sample of densely assembled nanoplates exhibited the highest photodegradation of 64% under UV light irradiation within 300 min.     

Hydrothermal synthesis and electrochemical properties of α-MoO3 nanobelts used as cathode materials for Li-ion batteries

Uniform α-MoO₃ nanobelts were successfully synthesized by the hydrothermal process at 180°C for 20 h of the acidic solutions with different pH values of 0–0.75, adjusted using HCl (conc.). XRD and SEM results revealed that the pH of the precursor solutions played an important role in the phase, impurities, and morphology of the products. At the pH=0, the perfect α-MoO₃ nanobelts with a few tens of microns long were synthesized. By the TEM characterization, orthorhombic MoO₃ has a distinctive layered structure along the [010] direction, consisting of distorted MoO₆ octahedrons connected by common corners along the [100] direction and common edges along the [001] direction. The electrochemical measurement showed that the α-MoO₃ nanobelts have high specific charge capacity.     

Synthesis,characterization and electrochemical properties of α-MoO<Subscript>3</Subscript> nanobelts for Li-ion batteries

Orthorhombic molybdenum trioxide (α-MoO₃) nanobelts have been successfully synthesized by hydrothermal method at 180°C for 20 h. The prepared α-MoO₃ samples were investigated by X-ray diffraction, Fourier transform IR spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy methods. It was found that α-MoO₃ nanobelts grow along the c-axis, with ±(100) top or bottom surfaces and ±(010) side surfaces. The prepared α-MoO₃ nanobelts were used as cathode materials for Li-ion batteries. They exhibit specific capacity of 1340 and 1250 mA h g^–1 at a current density of 100 and 400 mA/g, respectively.