ABSTRACT
Simple one-step solvothermal route was used to synthesize γ-Bi2O3 nanostructures. Well-defined nanoflowers and finite nanorods surface morphology of the samples were revealed. The physical characterization and material confirmation was explored by employing X-ray diffraction (XRD), Raman, photoluminescence (PL), and Fourier transform infrared (FTIR) studies. The optical bandgap of about 2.71 and 2.72 eV was observed for nanoflower and nanorods, respectively. The highest specific surface area of 0.877 m²/g with mesoporous feature was reported for nanoflower sample. The improved photocurrent of 12.47 µA/cm² was observed for the nanoflower photoanode with lowest internal resistance and the highest stability over 3600 s, with 87% retention in photocurrent was estimated from chronoamperometry (CA) study. The effective methyl orange degradation of MO as 94% was investigated by nanoflower photocatalyst. The synthesis of metastable γ-Bi2O3 nanostructures with hierarchical morphology to adapt as an efficient photoanode for solar water splitting and pollutant degradation applications was reported.
ABSTRACT
Polyvinylpyrrolidone (PVP)-assisted nanocatalyst preparation was succeeded by employing a controlled solvothermal route to produce efficient electrodes for electrochemical water-splitting applications. Bi2WO6 and FeWO4 nanocatalysts have been confirmed through the strong signature of (113) and (111) crystal planes, respectively. The binding natures of Bi-W-O and Fe-W-O have been thoroughly discussed by employing X-ray photoelectron spectroscopy which confirmed the formation of Bi2WO6 and FeWO4. The freestanding nanoplate array morphology of Bi2WO6 and the fine nanosphere particle morphology of FeWO4 nanocatalysts were revealed by scanning electron microscopy images. With these confirmations, the fabrication of durable, long-term electrodes for electrochemical water splitting has been subjected to efficient oxidation of water, confirmed by obtaining 2.79 and 1.96 mA/g for 0.5 g PVP-assisted Bi2WO6 and FeWO4 nanocatalysts, respectively. The water oxidation mechanism of both nanocatalysts has been revealed with the support of 24 h stability test over continuous water oxidation and faster charge transfer achieved by the smaller Tafel slope values of 75 and 78 mV/dec, respectively. Generally, these nanocatalysts are utilized for photocatalytic applications. The present study revealed the PVP-assisted synthesis to produce electrocatalytically active nanocatalysts and their electrochemical water-splitting mechanism which will offer a pathway for research interests with regard to the production of multifunctional nanocatalysts for both electro- and photocatalytic applications in the near future.
ABSTRACT
We reported a simple and economical SDS (sodium dodecyl sulfate) assisted BiVO4 solvothermal synthesis of BiVO4 nanostructures. The implementation of pristine and SDS assisted BiVO4 nanostructure as photoanode in photoelectrochemical (PEC) water splitting was investigated. The good crystalline nature, defects present in the material, recombination nature and vibrational properties of the synthesized BiVO4 nanostructures have been analyzed and confirmed by XRD, Raman, PL and FTIR studies. The constructed nanoflower oriented morphology combined with nanorods for SDS assisted BiVO4 have been examined by SEM studies. The optical band gap differences were observed as 2.35 and 2.31 eV for pristine and SDS assisted BiVO4 nanostructures respectively. The higher photocurrent density of 5.8 µA/cm² at 0.5 V versus RHE with lower flat band potential of -0.75 V revealed for SDS assisted BiVO4 nanostructured photoanodes. Good conductivity, higher charge separation efficiency and 52% photocurrent retention under illumination was reported over 7200 s for the same efficient photoanode. These results suggested the substantial possibility of BiVO4 nanostructures synthesized by using SDS surfactant could be utilized as efficient photoanodes for PEC water splitting applications.
