Published December 7, 1988 | Version v1
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Electrochemical study of RuO2 and/or TiO2 pyrolytic films on titanium in the range of voltage corresponding to water stability

Creators

Description

This research thesis can be considered as a preliminary part of the investigation of electrocatalytic properties of ruthenium and titanium dioxides. It proposes a presentation of electrochemical properties of interfaces between these oxides and the aqueous electrolyte in a voltage range corresponding to thermodynamic stabilities of water and dioxides. After a bibliographical study of methods of preparation of these materials and on the influence of the preparation mode on their physical characteristics and transient electrochemical behaviours, the author reports a detailed study of the hydrogen atom electro-sorption reaction. He discusses the variation of the main electrostatic characteristics of the space charge layer of various semiconducting phases with respect to the initial electric potential between the ends of this layer. He reports the experimental study of electrodes with porous ruthenium and / or titanium dioxides formed by pyrolysis or co-pyrolysis of chlorides of these metals

Abstract (French)

L'etude electrochimique, par des methodes transitoires (voltamperometrie, impedance complexe, chronopotentiometrie) montre que l'interface RuO2 pyrolytique / electrolyte aqueux est le siege de reactions d'electrosorption (s + H+ + e- → s,H) localisees sous la surface hydroxylee, reactions qui sont superposees a l'electroinsertion de l'hydrogene. Selon les conditions experimentales, ces processus sont limites par la porosite de l'oxyde, le transfert de charge, la diffusion de l'hydrogene en phase solide et / ou la variation interfaciale du pH. Substituer en quasi-totalite Ru par Ti conduit a des materiaux ou coexistent, en contact ohmique (impolarisable), les phases RuO2 metal et TiO2 semi-conducteur de type n. En raison de la polycristallinite de RuO2, les resultats sont analyses en terme d'isothermes de Langmuir et de Frumkin et non au moyen d'un nouveau modele que nous presentons et qui suppose l'existence, en surface, de niveaux energetiques specifiques pour l'ion H+ et pour e-. Pour la meme raison, le modele classique de l'interface semi-conducteur / electrolyte que nous developpons pour estimer l'effet de la capacite differentielle de la couche d'Helmoltz sur les variatioons, avec la tension, des ddp aux bornes de cette couche et aux bornes de la couche de charge d'espace, et de la capacite differentielle de cet interface, n'est pas applique a nos resultats experimentaux. Cependant, son utilisation nous a permis d'ameliorer les interpretations anterieurement proposees pour la variation, avec la tension, de la capacite differentielle des interfaces ZnO (monocristal, semi-conducteur de type n) et C (graphite pyrolytique hautement oriente, semi-metal intrinseque) electrolytes aqueux, materiaux degeneres ou dont la degenerescence est induite par polarisation. (auteur)

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Additional details

Additional titles

Original title (French)
Etude electrochimique de films pyrolytiques de RuO

Identifiers

URL
http://www.iaea.org/inis/contacts/;

Publishing Information

Imprint Pagination
398 p.
Report number
FRNC-TH--8386

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
44067385
Subject category
S36: MATERIALS SCIENCE;
Resource subtype / Literary indicator
Thesis, Bibliography
Descriptors DEI
BIBLIOGRAPHIES; CATALYTIC EFFECTS; CRYSTAL-PHASE TRANSFORMATIONS; ELECTRIC POTENTIAL; ELECTROCATALYSTS; ELECTROCHEMISTRY; ELECTROLYTES; INTERFACES; MICROSTRUCTURE; PYROLYSIS; PYROLYSIS PRODUCTS; RUTHENIUM OXIDES; SORPTION; SORPTIVE PROPERTIES; THERMODYNAMIC PROPERTIES; TITANIUM OXIDES
Descriptors DEC
CATALYSTS; CHALCOGENIDES; CHEMICAL REACTIONS; CHEMISTRY; DECOMPOSITION; DOCUMENT TYPES; OXIDES; OXYGEN COMPOUNDS; PHASE TRANSFORMATIONS; PHYSICAL PROPERTIES; REFRACTORY METAL COMPOUNDS; RUTHENIUM COMPOUNDS; SURFACE PROPERTIES; THERMOCHEMICAL PROCESSES; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS

Optional Information

Notes
306 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS website for current contact and E-mail addresses: http://www.iaea.org/inis/contacts/