Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction

The anodic reaction occurring during the electrolysis of molten nitrates on graphite electrodes at temperatures from 230 to 320°C has been studied. The overall reaction is <math><mrow is="true"><mn is="true">2</mn><mo is="true">N</mo>...

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Autores principales: Arvia, Alejandro Jorge, Triaca, Walter Enrique
Formato: Articulo
Lenguaje:Inglés
Publicado: 1966
Materias:
Ciencias Exactas
Química
Molten nitrates
Graphite electrodes
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/120668
https://www.sciencedirect.com/science/article/abs/pii/0013468666800361
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-120668
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Química
Molten nitrates
Graphite electrodes
spellingShingle Ciencias Exactas
Química
Molten nitrates
Graphite electrodes
Arvia, Alejandro Jorge
Triaca, Walter Enrique
Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
topic_facet Ciencias Exactas
Química
Molten nitrates
Graphite electrodes
description The anodic reaction occurring during the electrolysis of molten nitrates on graphite electrodes at temperatures from 230 to 320°C has been studied. The overall reaction is <math><mrow is="true"><mn is="true">2</mn><mo is="true">N</mo><msubsup is="true"><mo is="true">O</mo><mn is="true">3</mn><mo is="true">−</mo></msubsup><mo is="true">+</mo><mo is="true">C</mo><mo is="true">=</mo><mo is="true">C</mo><msub is="true"><mo is="true">O</mo><mn is="true">2</mn></msub><mo is="true">+</mo><mn is="true">2</mn><mo is="true">N</mo><msub is="true"><mo is="true">O</mo><mn is="true">2</mn></msub><mo is="true">+</mo><mn is="true">2</mn><mo is="true">e</mo></mrow></math> Current/voltage curves in the range 0·5–200 mA/cm<sup>2</sup> fit a Tafel line with a slope 2RT/F. The decay of anodic overvoltage is logarithmic with time in a region beyond 10 ms, depending on the current density. The decay process indicates a high pseudo-capacitance, which decreases as the anodic overvoltage increases. Results obtained from steady current/voltage curves, decay and build-up of the anodic overvoltage, and the temperature effect can be explained with the aid of known results on the kinetics of thermal oxidation of graphite and on the anodic reaction taking place on platinum electrodes. At high overvoltage a high degree of oxidation caused by the NO 3 intermediate is achieved, and the rate-determining step of the anodic reaction is then <math><mrow is="true"><mo is="true">C</mo><mo stretchy="false" is="true">(</mo><mo is="true">O</mo><mo stretchy="false" is="true">)</mo><mo is="true">+</mo><mo is="true">N</mo><msubsup is="true"><mo is="true">O</mo><mn is="true">3</mn><mo is="true">−</mo></msubsup><mo is="true">→</mo><mo is="true">N</mo><msub is="true"><mo is="true">O</mo><mn is="true">2</mn></msub><mo is="true">+</mo><mo is="true">C</mo><msub is="true"><mo is="true">O</mo><mn is="true">2</mn></msub><mo is="true">+</mo><mo is="true">e</mo></mrow></math> A stable residual cell formed after the interruption of electrolysis is discussed in terms of the reactions in the proposed reaction path.
format Articulo
Articulo
author Arvia, Alejandro Jorge
Triaca, Walter Enrique
author_facet Arvia, Alejandro Jorge
Triaca, Walter Enrique
author_sort Arvia, Alejandro Jorge
title Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
title_short Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
title_full Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
title_fullStr Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
title_full_unstemmed Electrolysis of molten nitrates on graphite electrodes : Kinetics of the anodic reaction
title_sort electrolysis of molten nitrates on graphite electrodes : kinetics of the anodic reaction
publishDate 1966
url http://sedici.unlp.edu.ar/handle/10915/120668
https://www.sciencedirect.com/science/article/abs/pii/0013468666800361
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