Asian Journal of Research in Chemistry

Kambiré Ollo ¹, Sadia Sahi Placide ², Kouakou Yao Urbain ³, Pohan Lemeyonouin Aliou Guillaume ⁴, Koffi Konan Sylvestre ², Kouadio Kouakou Etienne ², Kimou Kouakou Jocelin ², Koné Souleymane ², Lassiné Ouattara ⁵

Affiliations
1 UFR Sciences et Technologies, Université de Man, BP 20 Man, Côte d’Ivoire, IN
2 Laboratoire de constitution et réaction de la matière, UFR SSMT, Université Félix Houphouët-Boigny de Cocody, Abidjan, 22 BP 582 Abidjan 22, Côte d’Ivoire., IN
3 UFR Sciences et Technologies, Université de Man, BP 20 Man, Côte d’Ivoire., IN
4 UFR Sciences Biologiques, Université Peleforo Gon Coulibaly de Korhogo, BP 1328 Korhogo, Côte d’Ivoire, IN
5 Laboratoire de constitution et réaction de la matière, UFR SSMT, Université Félix Houphouët-Boigny de Cocody, Abidjan, 22 BP 582 Abidjan 22, Côte d’Ivoire ., IN

Abstract

The platinum anode modified by metal oxides electrodes degrades Abidjan wastewater which contains a high concentration of Cl- . During this degradation process, the organic polluants are oxidized, O2 and Cl2 are produced. The purpose of this study is to contribute to the understanding of these reaction mechanisms by studying the kinetics of O2 and Cl2 evolution at neutral pH on Pt. The study was performed by interpreting the voltammograms and Tafel slopes obtained. The voltammetric measurements were carried out using an Autolab Potentiostat from ECHOCHEMIE (PGSTAT 20) connected by interface to a computer. Pt electrode was prepared on titanium (Ti) substrate by thermal decomposition techniques at 400°C. The characterization of the surface of the prepared electrode by scanning electron microscopy and X-ray photoelectron spectrometry showed the presence of platinum on its surface. The results obtained show that the OH· are adsorbed on the active sites of Pt. Then they react to form PtO. Then by reaction between the surface oxygen and PtO, O2 is produced and the active sites are regenerated. In the presence of low Clconcentration, there is a competition between the Cl2 and O2 evolution reactions. However, Cl2 only is produced for high Clconcentrations. The kinetics of the evolution reaction of chlorine increases with the concentration of Cland remains constant for concentrations greater than 0.5 M. This study also showed that the chlorine reduction reaction produced in solution is a diffusion-controlled reaction for low scan rates.

Keywords

Oxidation, Platinum, Oxygen, Chlorine, Kinetic

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