Electrochemical Kinetics of Anodic Ni Dissolution in Aqueous Media as a Function of Chloride Ion Concentration at pH Values Close to Physiological Conditions |
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Authors: | Hanna Ayoub Virginie Lair Sophie Griveau Philippe Brunswick José H Zagal Fethi Bedioui Michel Cassir |
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Institution: | 1. Chimie ParisTech, LECIME, CNRS UMR 7575, 11 rue Pierre et Marie Curie, 75213 Paris cedex 05, France;2. UPCGI CNRS 8151/INSERM U 1022, Université Paris Descartes, Chimie ParisTech, 11 rue Pierre et Marie Curie, 75231 Paris cedex 05, France;3. IMPETO Medical, 17 rue campagne Première, 75014 Paris, France;4. Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40, Correo 33, Santiago 9170022, Chile |
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Abstract: | We have studied the electrochemical kinetics of anodic Ni dissolution as a function of chloride ion concentration, at pH 5, 6 and 7, in order to mimic the conditions of sweat samples. Our results show that the rate‐determining step for Ni dissolution in the mentioned pH range is the transfer of one first electron, as suggested by the Tafel slopes close to 0.120 V/decade. However, the reaction order in chloride ion varies from ca. 2 at pH 7 to values close to unity for pH values between 5 and 6. This finding is very important for sensor applications in sweat fluids since the sensitivity of the Ni electrode to chloride ions is higher in neutral solutions (pH ca. 7) compared to that in slightly acid solutions (pH between 5 and 6). Small variations in pH in real samples are expected so this change in sensitivity should be considered when sensing chloride ions in sweat fluids. |
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Keywords: | Nickel Electrochemical kinetics Sensors Chloride ions |
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