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Tungstate nanorods (WO3 -NRs) were synthesized by a facile hydrothermal method using sodium tungstate as a precursor while sodium sulfate and hydrochloric acid were used as stabilizing agents. Scanning electron microscopy (SEM) images showed outstanding growth of WO3-NRs with uniform surface morphology. The X-ray diffraction (XRD) analysis confirmed the purity and crystalline nature of the synthesized material. The material was further characterized by different tools such as TEM, EDX, FTIR, XPS, BET, and Raman spectroscopy. For the electrochemical response of WO3-NRs, cyclic voltammetry measurements were performed for the detection of vitamin C (ascorbic acid). The designed sensor shows a limit of detection of 0.56 µM and higher selectivity in the presence of its structural and functional analogs such as uric acid and lauric acid. Improved sensing properties of WO3-NRs are attributed to the synergistic effects involving the quantum effect, high surface area, fast electron transfer, and highly ordered 1-D nanostructure. Among them, the highly arranged 1-D growth of WO3 nanorods has a greater impact on the efficiency of the biosensor. These results provide a new insight for the synthesis of 1-D nanostructures of transition metal oxides for contributions in sensor devices, solar cells, and capacitor applications. [ABSTRACT FROM AUTHOR]

Metal oxide based electrodes are attractive for energy storage applications with limited characteristics of flexibility due to inherent rigid structure. However, incorporation of flexible insulating matrix within metal oxide composites result in poor electrically conductive and energy storage characteristics. This study presents the fabrication of flexible MnO2 based composite electrodes prepared by incorporation of lignocelluloses (LC) fibers, directly collected from a self-growing plant, Monochoria Vaginalis. Furthermore electrodeposition of silver (Ag) nanoparticles was performed on LC/MnO2 in potentiostatic mode to address the electrically conductive characteristics. Morphology, structural, conductive and energy storage properties of fabricated electrodes are analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), impedance analyzer and potentiostat, respectively. SEM images clearly indicate the deposition of Ag nanoparticles on MnO2 nanorods embedded in LC fibers whereas FTIR results confirm the bonding of the functional groups. Cyclic voltammetry measurements showed efficient kinetics of LC/MnO2 after electrodeposition of Ag nanoparticles. The effects on electrical properties associated with blending MnO2 nanorods in lignocelluloses fibers and Ag deposition on MnO2 in LC/MnO2 are explored in wide frequency range between 10 Hz and 5 MHz. However, deposition of Ag nanoparticles on MnO2 nanorods surfaces acts as a conductive path and reduces the associated resistance. Incorporated flexibility in rigid structure of MnO2 and further improvements in conductive and energy storage characteristics will open the possibilities to be used as electrode in modern bendable energy storage devices. [ABSTRACT FROM AUTHOR]

V2O3 samples were successfully prepared using [VOSO4·xH2O] as the starting material by a template-free hydrothermal method with the addition of KBrO3. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The XRD result shows the rhombohedral structure for V2O3 with an average crystallite size in the range of 22 nm. With the increase in reaction time (6-8 h), the morphology of the samples changes from nano-flower to nano-ribbons as indicated by SEM micrographs. FTIR spectrum shows that the band at 1286 cm−1, related to C-OH stretching and OH bending vibrations and indicate the presence of residual hydroxyl groups. The electrochemical measurements show an excellent storage response, kinetics and reversibility of the electrode material. Further, good rate capability of the materials was also observed. [ABSTRACT FROM AUTHOR]

Structural, morphological, dielectric and electrical properties of Zr1−xNixTiO4 (x = 0, 0.05, 0.10, 0.15 and 0.2) are studied in this work using X-ray diffraction, field emission scanning electron microscopy and impedance spectroscopic measurements, respectively. The compositions were prepared using sol-gel auto-combustion method and observed to possess the orthorhombic structure with a space group, Pnab 60. The Fourier transform infrared spectroscopy inveterated that the combustion was complete. Field emission scanning electron microscopic study reveals that the homogeneity and density of the particles increase with increasing doping concentration. Grain size increases with increasing Ni contents i.e. from 0.25 to 0.5 µm, mostly depicting irregular morphology. Energy dispersive X-ray technique confirmed the presence of Ni, Zr, Ti and O in the prepared materials. Dielectric parameters i.e. dielectric constant and loss decreases with increasing frequency. Conductivity increases with increasing Ni contents and with the increase in frequency. Complex impedance plot shows a single semicircle corresponding to ZrTiO4 and Ni-doped ZrTiO4 which determines the dominancy of grain boundary resistance at low frequency. Electric modulus reveals the real dielectric relaxation process. [ABSTRACT FROM AUTHOR]