Novel application of an in situ radiotracer method for the study of the formation of surface adlayers in the course of Cr(VI) reduction on a gold electrode

A novel radiotracer method to study the formation of surface adlayers in the course of Cr(VI) reduction of a gold electrode

“…5, which were determined in 1 mol dm -3 HC104 electrolyte by making use of the empirical calibration relationship (curve 1) and the model calculation elaborated for p-emitting radionuclides (curve 2), correlate well to each other within the regions indicated by error bars. (As well documented in [10], the F vs. E relationships measured in HC104 electrolyte exhibit basically the same character both in the presence and absence of HSO4-]SO42-ions.) Although these results give independent verifications of the precision of the calculated F values, the surface excess obtained by model calculation may be underestimated.…”

“…The applicability of the radionuclides emitting low energy X-radiation in the in situ radiotracer sorption studies was detailed in our earlier papers [9,10]. The novelty of the present in situ radiotracer approach is the method elaborated for the detec- Table 1.…”

“…Empirically determined analytical functions were used for quantitative characterisation of the scintillation spectra. The X-ray peaks of the scintillation spectra were fitted by a Gaussian-type function, and for description of the continuous background intensity a log-log type 4 th degree polynomial function was found to be convenient [10]. Following the above deconvolution of the detected spectra, the F values of the surface Cr-particles were evaluated from the net X-ray intensity by both model calculation and empirical calibration methods, as described in [10].…”

“…The uncertainty of the surface excess of Crcontaining particles in the range of detected intensity values was found not to be higher than 53%., i.e. Gr< 0.53 F [10]. Figure 2 shows the cyclic voltammetric curves at a polycrystalline gold electrode in 1 mol dm -3 HC104 + 2 x 10 -4 mol dm -3 H2SO 4 electrolyte (pH = 0) in the presence (curves 1-4) and absence (curve 5) of 2 x 10 -4 mol dm -3 Cr(VI) species.…”

In situ radiotracer and voltammetric study of the formation of surface adlayers in the course of Cr(VI) reduction on polycrystalline and (111) oriented platinum

“…Independent radiotracer studies have revealed that the reduction of Cr(VI) ions is accompanied with an induced adsorption of HSO 4 − /SO 4 2− ions present in the solution phase [8,[11][12][13]. In addition, recent findings obtained in our laboratory by in situ radioactive labeling (HSO 4 − /SO 4 2− labeled with 35 S and Cr-containing species labeled with 51 Cr were used) attest the continuous formation of an intermediate surface complex containing Cr(VI) species and HSO 4 − /SO 4 2− ions at the early stage of the Cr(VI) electroreduction [13]. Observations made in Ref.…”