Monoclinic bismuth oxide nanosheets (α-Bi2O3 NSs) of average thickness 28nm were successfully synthesized via hydrothermal method. Various characterization techniques such as powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Ramman spectroscopy, UV-Vis spectroscopy and Field Emission scanning electron microscopy (FE-SEM) coupled with Energy dispersive x-ray spectroscopy (EDXS) were employed to investigate the prepared bismuth oxide nanopowder in terms of its structural, morphological and optical properties. Electrochemical measurements of α-Bi2O3 NSs deposited on nickel foam substrate were carried out in 6 M KOH electrolyte to examine its supercapacitive performance. The α-Bi2O3 NSs based electrode with 90 wt% active material exhibited excellent electrochemical performance with pronounced oxidation and reduction peaks, confirming the pseudocapacitive behaviour with a high specific capacitance of 764.5 Fg-1 at 5 mVs-1 scan rate. The electrode also presented good cycling stability of about 69% capacitive retention after 3000 cycles measured at 10 mAcm-2 current density. This enhanced supercapacitive performance is attributed to the increased effective surface area offered by widely open and ultrathin nanosheet like morphology.
A photoelectrochemical investigation of photoanodes based on hematite nanorods and nanospheres fabricated via hydrothermal technique is reported. The fabricated nanostructures have been thoroughly analyzed and characterized using field emission scanning electron microscopy, X-ray diffractometer, UV-Visible spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. The presence of oxygen vacancies and morphological characteristics of Hematite photoanodes were shown to be directly related to their photoelectrochemical performances. The nanorod-based photoanode yields an excellent photocurrent density of 1.63 mAcm2 which was about four times greater than the nanosphere-based photoanode. Furthermore, hematite nanorods showed efficient charge transfer kinetics, increased donor density and, excellent photo stability. The enhancement in photoelectrochemical properties of nanorods can be attributed to the oxygen vacancies generated in hematite nanorods which provide excellent electrical conductivity and better charge transfer kinetics. The results demonstrate that oxygen vacancy-rich nanorods can serve as ideal photoelectrode for enhancing the electrochemical properties of hematite nanostructures.
One-dimensional TiO2 nanostructures like nanotubes, nanowires, and nanorods have received huge attention due to their photocatalytic hydrogen-generating ability. However, its wide band gap and high charge carrier recombination rate hampered the efficiency with which it converts solar energy into hydrogen. To improve this application, metallic doping employing a quick and easy synthesis method should be proposed. In this study, we report on the microwave-assisted hydrothermal synthesis of iron-doped TiO2 nanowires on an FTO substrate. The formation of TiO2 nano-wires was validated by structural and morphological analysis carried out using XRD and SEM imaging respectively. To verify the presence of dopants in the samples, EDX was employed to provide a breakdown of their chemical composition. The impact of Fe-doping on optical and photoelectrochemical properties was studied. Electrochemical impedance spectroscopy was used to determine the mechanisms behind charge accumulation and charge transfer properties. The Mott-Schottky plot was used to examine the donor density and the flat-band potential of the pristine and Fe-doped TiO2 samples
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