D. Scherson, Jing Xu
Oct 27, 2013
Citations
0
Influential Citations
0
Citations
Journal
Journal name not available for this finding
Abstract
A series of UV visible reflection absorption spectr a were then acquired in the same solution at various ω values in the range 400 < ω < 2500 rpm with the Pt RDE polarized at 1.45 V (see Fig. 2), yielding in each case a very prominent peak at 266 nm, characteristic of tribromide in aqueous solutions. 2 Unlike the results obtained for iron hexacyanoferrate reported in our previous study using a similar RDE spectroscopy sys tem, the optical signal for the present system was found to increase monotonically with the rotation rate. One possible explanation for this behavior may be found in the much higher molar absorptivity of tribromide (4.09 × 10 cm/mol) compared to that of the iron complex (1.75 × 10 cm/mol) at their corresponding absorption maxima, i.e. 266 and 390 nm, respectively. Some evidence in support of this view was provided by monitoring the absorbance at the limiting current as a function of time which as shown in Fig. 3 increased rather markedly for all rotating rates examined, where the lack of linearit y is in all likelihood related to the evaporation of bromin e from the solution. Efforts are currently underway to mon it r the reflectance of the surface at near normal incid ence at a fixed wavelength away from the absorption bands of the electrolyte while the bromide is being oxidized on the surface of the Pt RDE. The results of these dual be m experiments will be reported in due course.