Electrochemical behaviour of a lead electrode in phosphoric acid |
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| Authors: | M Chatelut S Chah-Bouzziri O Vittori A Benayada |
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| Institution: | (1) Laboratoire d'Electrochimie Analytique – LICAS, Université Claude Bernard Lyon I, Bat 308 ESCPE, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France e-mail: vittori@cpe.fr Tel.: +33-04-72431413; Fax: +33-04-42448479, FR;(2) Ecole Mohamadia d'Ingenieurs, Rabat, Avenue Ibn Sina, BP 765, Rabat-Agdal, Morocco, MA |
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| Abstract: | A lead electrode was studied in 6 and 12 M H3PO4. Oxidation of a freshly polished electrode occurred in the −0.5 to −0.3 V vs. SCE range, and led to PbHPO4 growth on the electrode surface. The dissolution of this layer by electrochemical reduction occurred between −0.5 and −0.7 V.
The influence of temperature (20 °C and 65 °C) was investigated and showed that the anodic and the cathodic peaks were increasing,
and more markedly for the 12 M H3PO4. The ratio Q
cathodic/Q
anodic (Q=electrical charge flowing through the electrode) was equal or close to the unity at 20 °C and decreased as the temperature
was increased. The influence of Cl−, Br− and I− ions was also evaluated. The addition of Cl− and Br− predominantly led to Pb5(PO4)3Cl and Pb5(PO4)3Br, respectively, while I− led to a mixture of PbI2 and PbHPO4.
Received: 18 July 1999 / Accepted: 2 November 1999 |
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| Keywords: | Lead Phosphoric acid Halide ions Cyclic voltammetry |
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