A cyclic voltammetric study of the behaviour of Br- and Br3- at Pt electrodes, in the potential range between hydrogen and oxygen evolution, is described. Different experiments were carried out, in the presence of Br- alone, and with a mixture of Br- and Br3-, in which the ratio between the species has been kept constant and equal to 1. The halide concentration was varied between 4E-6 and 1E-3 mol dm-3, at constant ionic strength, in 1M HClO4 as well as in 1M NaClO4 adjusted to a pH of 2. Underpotential deposition of Br is observed at potentials as low as -0.125V vs SCE. The adsorption parameters of Br species were determined from the adsorption/desorption peak pair in the hydrogen adsorption/desorption region, and from the oxide reduction peak data. In the absence of oxygen adsorption, a relatively high coverage of the electrode surface is attained. A Langmuir-type adsorption is observed under the different experimental conditions.
The Bromine Electrode. Part I: Adsorption Phenomena at Polycrystalline Platinum Electrodes
FERRO, Sergio;DE BATTISTI, Achille
2004
Abstract
A cyclic voltammetric study of the behaviour of Br- and Br3- at Pt electrodes, in the potential range between hydrogen and oxygen evolution, is described. Different experiments were carried out, in the presence of Br- alone, and with a mixture of Br- and Br3-, in which the ratio between the species has been kept constant and equal to 1. The halide concentration was varied between 4E-6 and 1E-3 mol dm-3, at constant ionic strength, in 1M HClO4 as well as in 1M NaClO4 adjusted to a pH of 2. Underpotential deposition of Br is observed at potentials as low as -0.125V vs SCE. The adsorption parameters of Br species were determined from the adsorption/desorption peak pair in the hydrogen adsorption/desorption region, and from the oxide reduction peak data. In the absence of oxygen adsorption, a relatively high coverage of the electrode surface is attained. A Langmuir-type adsorption is observed under the different experimental conditions.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
