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Enhanced electrical properties in sub-10-nm WO3 nanoflakes prepared via a two-step sol-gel-exfoliation method.

Zhuiykov S, Kats E - Nanoscale Res Lett (2014)

Bottom Line: The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques.CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method.It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science and Engineering Division, CSIRO, 37 Graham Road, Highett, VIC 3190, Australia.

ABSTRACT
The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques. CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

No MeSH data available.


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Linear voltammograms of commercial WO3, Q2D WO3 nanoflakes and hexagonal WO3 nanowires in 1.0 M H2SO4 solution (A). Insert, measured electrochemical stability for 100 cycles at -0.1 V (vs RHE). (B) Corresponding Tafel plots obtained from the LSV.
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Figure 9: Linear voltammograms of commercial WO3, Q2D WO3 nanoflakes and hexagonal WO3 nanowires in 1.0 M H2SO4 solution (A). Insert, measured electrochemical stability for 100 cycles at -0.1 V (vs RHE). (B) Corresponding Tafel plots obtained from the LSV.

Mentions: LSV voltammograms for commercial WO3 (surface area = 3 m2 g-1) [49] and Q2D β-WO3 nanoflakes sintered at 550°C were recorded in a potential region of +0.1 to -0.2 V at a scan rate of 50 mV s-1 in 1.0 M H2SO4 solution. The results are presented in Figure 9A. Recent LSV results for hexagonal WO3 nanowires [15] in the same solution and at the same scan rate and potential range were also provided for comparison. It is clearly shown that the commercial WO3 exhibited very low catalytic activity towards electrochemical reaction for HER in this potential region, whereas Q2D β-WO3 nanoflakes sintered at 550°C displayed improved electro-catalytic activity. The observed electrochemical stability was recorded for 100 consecutive cycles in the solution (insert in Figure 9A) and confirmed only ~5% decrease from the initial current density. It can therefore be concluded that the activity of electrochemical reaction in this acid media of Q2D WO3 nanoflakes remains high after a substantial number of working cycles. In contrast to the commercial WO3, which consists of randomly oriented particles of the different size, the developed Q2D β-WO3 nanoflakes possess high aspect ratio and high crystallinity which stipulates the high electro-catalytic activity.


Enhanced electrical properties in sub-10-nm WO3 nanoflakes prepared via a two-step sol-gel-exfoliation method.

Zhuiykov S, Kats E - Nanoscale Res Lett (2014)

Linear voltammograms of commercial WO3, Q2D WO3 nanoflakes and hexagonal WO3 nanowires in 1.0 M H2SO4 solution (A). Insert, measured electrochemical stability for 100 cycles at -0.1 V (vs RHE). (B) Corresponding Tafel plots obtained from the LSV.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4150682&req=5

Figure 9: Linear voltammograms of commercial WO3, Q2D WO3 nanoflakes and hexagonal WO3 nanowires in 1.0 M H2SO4 solution (A). Insert, measured electrochemical stability for 100 cycles at -0.1 V (vs RHE). (B) Corresponding Tafel plots obtained from the LSV.
Mentions: LSV voltammograms for commercial WO3 (surface area = 3 m2 g-1) [49] and Q2D β-WO3 nanoflakes sintered at 550°C were recorded in a potential region of +0.1 to -0.2 V at a scan rate of 50 mV s-1 in 1.0 M H2SO4 solution. The results are presented in Figure 9A. Recent LSV results for hexagonal WO3 nanowires [15] in the same solution and at the same scan rate and potential range were also provided for comparison. It is clearly shown that the commercial WO3 exhibited very low catalytic activity towards electrochemical reaction for HER in this potential region, whereas Q2D β-WO3 nanoflakes sintered at 550°C displayed improved electro-catalytic activity. The observed electrochemical stability was recorded for 100 consecutive cycles in the solution (insert in Figure 9A) and confirmed only ~5% decrease from the initial current density. It can therefore be concluded that the activity of electrochemical reaction in this acid media of Q2D WO3 nanoflakes remains high after a substantial number of working cycles. In contrast to the commercial WO3, which consists of randomly oriented particles of the different size, the developed Q2D β-WO3 nanoflakes possess high aspect ratio and high crystallinity which stipulates the high electro-catalytic activity.

Bottom Line: The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques.CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method.It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Materials Science and Engineering Division, CSIRO, 37 Graham Road, Highett, VIC 3190, Australia.

ABSTRACT
The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques. CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures.

No MeSH data available.


Related in: MedlinePlus