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. Histone Methyltransferase antagonist 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 Temsirolimus nmr 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 LY2603618 developed Q2D β-WO3 nanoflakes possess high aspect ratio and high crystallinity which stipulates the high electro-catalytic activity. Figure 9 Linear voltammograms of commercial WO 3 , Q2D WO 3 nanoflakes and hexagonal WO 3 nanowires in 1.0 M H 2 SO 4 solution (A). Insert, measured electrochemical stability for 100 cycles at -0.1 V (vs RHE). (B) Corresponding Tafel plots obtained from the LSV. The Tafel plots (Figure 9B) were constructed from the LSV voltammograms

in the voltage region of -0.02 to -0.20 V. The Tafel slopes for commercial WO3, Q2D WO3 nanoflakes and hexagonal WO3 nanowires are -157, -112 and -116 mV decade-1, respectively [15]. The lower Tafel slope obtained from Q2D WO3 nanoflakes indicates that it is a superior material as a hydrogen production electrode of HER compared to hexagonal WO3 nanowires [15] and commercial WO3 [49]. This could be attributed to the enhanced electrons transfer kinetics in ultra-thin

Q2D nanoflakes, which can play a decisive role as a driving force to reduction of the electrochemical resistance [50]. These results demonstrate that Q2D β-WO3 nanoflakes developed via two-step sol-gel-exfoliation method can be effective electrode materials with improved HER activity. Conclusions Orthorhombic Q2D β-WO3 nanoflakes, typically with lengths and widths of the order of 50 to 100 nm and thickness of 7 to 9 nm were produced by a two-step sol-gel-exfoliation method. It was experimentally determined Thiamet G that exfoliation of the ultra-thin Q2D β-WO3 nanoflakes was only possible at nanostructures sintered at 550 and 650°C. Spectral evidence for β-WO3 phase exists in the Raman measurements. This is also consistent with the absence of other crystalline phases in the XRD measurements of this material. CSFS-AFM, FTIR, Raman and electrochemical measurements further confirmed that the annealing temperature of 550°C is the most acceptable sintering temperature for WO3, if ultra-thin Q2D β-WO3 nanoflakes with thickness of ~7 to 9 nm have to be obtained.