EP0033363B1 - Procédé de revêtement d'une électrode poreuse - Google Patents

Procédé de revêtement d'une électrode poreuse Download PDF

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Publication number
EP0033363B1
EP0033363B1 EP80107001A EP80107001A EP0033363B1 EP 0033363 B1 EP0033363 B1 EP 0033363B1 EP 80107001 A EP80107001 A EP 80107001A EP 80107001 A EP80107001 A EP 80107001A EP 0033363 B1 EP0033363 B1 EP 0033363B1
Authority
EP
European Patent Office
Prior art keywords
electrode
compounds
metals
process according
platinum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80107001A
Other languages
German (de)
English (en)
Other versions
EP0033363A1 (fr
Inventor
Günter Dr.rer.nat. Bewer
Hubertus Härle
Dieter Ing.Grad. Lieberoth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sigri GmbH
Original Assignee
Sigri GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sigri GmbH filed Critical Sigri GmbH
Publication of EP0033363A1 publication Critical patent/EP0033363A1/fr
Application granted granted Critical
Publication of EP0033363B1 publication Critical patent/EP0033363B1/fr
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
    • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
    • C25B11/093—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one noble metal or noble metal oxide and at least one non-noble metal oxide

Definitions

  • the invention relates to a method for coating a porous electrode for electrochemical processes with an activation layer which at least partially covers the electrode surface and contains metals or compounds of metals of the platinum group.
  • Electrodes for electrochemical processes e.g. B. of anodes for chlor-alkali electrotysis, from a resistant to the electrotysis products and a passivation layer forming material under the conditions of electrolysis
  • numerous methods have become known, the purpose of which essentially consists of a platinum metal or platinum metal-containing compounds in an electrochemically effective degree of dispersion anchor the electrode or the electrode core mechanically.
  • DE-B-1155762 it is known to galvanically coat degreased and etched titanium plates with a platinum metal and the plates in a first thermal cycle in an inert atmosphere and in a second cycle in an oxidizing atmosphere up to a temperature of approximately To heat 800 ° C.
  • This treatment gives a firmly adhering activation layer and at the same time improved protection of the electrode material by converting the titanium core, which is exposed in the pores of the activation layer and has a thin barrier layer made of titanium oxide, into rutile.
  • this and other known coating methods are less suitable for porous electrodes, for example for sintered electrodes according to DE-A-23 05 175 or electrodes made of titanium suboxide according to DE-B-24 05 010.
  • the adhesive strength of the activation layers is particularly favorable for porous electrodes and for The large surface area of the electrode is advantageous for numerous electrochemical processes.
  • the invention has for its object to provide a coating method for porous electrodes that does not have the disadvantages described, especially the comparatively large need for activating agents, and results in highly effective activation layers with small amounts of platinum metals.
  • the object is achieved according to the invention with a method of the type mentioned at the outset by coating the electrode surface with a fine-grained compounds of metals of the platinum group and a suspension containing the compounds which dissolve the compounds at an elevated temperature, the fine-grained compounds of the metals having a particle diameter, that only the dispersing agent can get into the pores of the electrode, but not the fine-grained compounds, that the dispersed phase of the suspending agent is dissolved, deposited on the electrode surface by evaporation of the agent and decomposed by heating the electrode to a temperature between 250 and 350 ° C and that the cycle is repeated several times and the electrode is then heated to a temperature between 400 and 600 ° C. in an oxygen-containing atmosphere.
  • the invention is based on the knowledge that particles dispersed in a suspension cannot get into pores which are only accessible through narrow hoses or channels, whereas the dispersing agent fills these pores.
  • the particle diameter must therefore correspond to the pore diameter. If the electrode is heated after coating, the dispersant emerges from the pores and, because of the increasing solubility of the platinum group compounds used according to the invention, dissolves the particles concentrated at the pore entrances.
  • the solution which is in a thin layer, has a relatively high toughness and is distributed evenly over the outer electrode surface and the surface of larger pores accessible from the outer surface without penetrating into narrow channel and tube pores.
  • the compounds deposited by evaporation of the solvent in a uniform layer thickness are then decomposed by heating the electrode to a temperature between 250 and 350 ° C., whereby a fissured, metallic surface coating having a large specific surface is formed.
  • the layer thickness of about 1 ⁇ m required for technical purposes is obtained by repeating the coating cycle several times.
  • the invention provides for the heating of the coated electrode in an oxidizing atmosphere, preferably in air, to a temperature between 400 and 600 ° C.
  • the main purpose of the thermal treatment is to passivate the electrode surface exposed in the pores of the activation layer and to anchor the activation layer on this surface.
  • Partial oxidation of the platinum metals contained in the activation layer is not harmful, since the growth of the metal crystals is inhibited and finely dispersed layers have greater electrochemical activity.
  • the treatment temperature should therefore not fall below or exceed the temperature range of 400 to 600 ° C.
  • the heating time is expediently about 3 to 60 minutes and can be easily determined by simple experiments for each electrode material and each compound used as an activating agent.
  • compounds of non-platinum metals are dispersed in the dispersant in addition to compounds of metals from the platinum group.
  • Suitable non-platinum metals are tantalum, zirconium, niobium, aluminum and especially titanium.
  • the activation layer then contains a finely dispersed mixture of platinum metals, oxides of platinum metals and oxides of non-platinum metals.
  • thermally decomposable complex compounds which contain free acid, in particular compounds from the group oxotato, formiato, tartrato and citrate complexes of metals from the group ruthenium, are used as compounds of metals of the platinum group and of non-platinum metals , Rhodium, palladium, iridium and platinum and analogous compounds of non-platinum metals.
  • the dispersant used according to the invention dissolves the complex compounds at elevated temperature, preferably with the electrode surface, in particular passivating layers, being formed by caustic solutions. Water and optionally aqueous oxalic acid solutions are particularly suitable for this purpose. In this process, the primer is improved without the formation of corrosive and harmful vapors as in the known use of hydrochloric acid platinum metal chloride solutions.
  • electrodes In principle, all electrically conductive metals, alloys and compounds that are stable under the conditions of electrochemical processes are suitable as electrodes.
  • electrodes are preferably used, e.g. B. as an anode for chlor-alkali electrolysis, passivating layers forming metals such as titanium, tantalum, zirconium and niobium and according to the invention preferably electrodes which consist at least in part of titanium suboxide.
  • the electrodes according to the invention have a porosity of about 10 to 50% and are generally produced by sintering moldings from a metal powder or an oxide powder.
  • the anode potential was checked with a Luggin capillary measured the saturated calomel electrode.
  • Composite plates as in Example 2 were treated with a slurry of 66 parts H 2 [Ru (C 2 O 4 ) 2 ] ⁇ 2.5 H 2 O, 70 parts H 2 [Ir (C 2 O 4 ) 3 ], 100 parts Ti 2 (C 2 O 4 ) 3 .10H 2 O coated in 1,000 parts of water and 50 parts of oxalic acid, annealed and the potentials measured.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)

Claims (7)

1. Procédé de revêtement d'une électrode poreuse prévue pour des processus électrochimiques avec une couche d'activation recouvrant au moins pour partie la surface de l'électrode et contenant des métaux et des combinaisons de métaux du groupe du platine, procédé caractérisé en ce que l'on revêt la surface de l'électrode avec une suspension contenant des combinaisons à grains fins de métaux du groupe du platine et un produit de dispersion dissolvant ces combinaisons à une température élevée, les combinaisons à grains fins des métaux présentant un diamètre de particules tel que seul le moyen de dispersion peut parvenir dans les pores de l'électrode, mais non les combinaisons à grains fins, puis on dissout la phase dispersée de la suspension par échauffement de l'électrode ainsi revêtue dans le produit de dispersion, on la dépose par vaporisation du produit--de dispersion sur la surface de l'électrode et paT chauffage de cette électrode à une température comprise entre 250 et 350 °C, on la décompose, on répète ce cycle plusieurs fois et on chauffe ensuite l'électrode dans une atmosphère contenant de l'oxygène à une température comprise entre 400 et 600 °C.
2. Procédé selon la revendication 1, caractérisé en ce que, dans le produit de dispersion, on disperse des combinaisons de métaux du groupe du platine et une combinaison de métaux n'appartenant pas à ce groupe.
3. Procédé selon les revendications 1 et 2, caractérisé en ce que l'on utilise un produit de dispersion constituant avec les combinaisons de métaux du groupe du platine, une solution attaquant à une température élevée, la surface de l'électrode.
4. Procédé selon les revendications 1 à 3, caractérisé en ce qu'on utilise des combinaisons du groupe des complexes oxalate, formiate, tartrate et citrate d'au moins un métal du groupe ruthénium, rhodium, palladium, iridium et platine.
5. Procédé selon les revendications 1 à 4 caractérisé en ce qu'on utilise de l'eau comme produit de dispersion.
6. Procédé selon les revendications 1 à 5, caractérisé en ce qu'on utilise une solution aqueuse d'acide oxalique comme moyen de dispersion.
7. Procédé selon les revendications 1 à 6, caractérisé en ce qu'on utilise une électrode constituée pour une partie au moins de sous- oxyde de titane.
EP80107001A 1980-02-05 1980-11-13 Procédé de revêtement d'une électrode poreuse Expired EP0033363B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3004080A DE3004080C2 (de) 1980-02-05 1980-02-05 Verfahren zum Beschichten einer porösen Elektrode
DE3004080 1980-02-05

Publications (2)

Publication Number Publication Date
EP0033363A1 EP0033363A1 (fr) 1981-08-12
EP0033363B1 true EP0033363B1 (fr) 1983-08-24

Family

ID=6093754

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80107001A Expired EP0033363B1 (fr) 1980-02-05 1980-11-13 Procédé de revêtement d'une électrode poreuse

Country Status (3)

Country Link
US (1) US4431686A (fr)
EP (1) EP0033363B1 (fr)
DE (1) DE3004080C2 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4530742A (en) * 1983-01-26 1985-07-23 Ppg Industries, Inc. Electrode and method of preparing same
EP0137911B1 (fr) * 1983-06-28 1988-07-27 BBC Brown Boveri AG Procédé de fabrication d'une couche dépassivante et couche dépassivante sur une électrode de cellule électrochimique
JPS60159185A (ja) * 1984-01-31 1985-08-20 Permelec Electrode Ltd 電極の製造方法
DE3516523A1 (de) * 1985-05-08 1986-11-13 Sigri GmbH, 8901 Meitingen Anode fuer elektrochemische prozesse
US4912286A (en) * 1988-08-16 1990-03-27 Ebonex Technologies Inc. Electrical conductors formed of sub-oxides of titanium
DE69528423T2 (de) * 1994-08-11 2003-06-26 Canon Kk Verwendung einer Lösung für die Herstellung einer elektroemittierenden Vorrichtung und Methode zur Herstellung von elektroemittierenden Vorrichtungen
JPH11111273A (ja) * 1997-09-29 1999-04-23 Furukawa Battery Co Ltd:The リチウム二次電池用極板の製造法及びリチウム二次電池
US20060255692A1 (en) * 2005-03-22 2006-11-16 Motohiro Yasui Piezoelectric Actuator, Ink-Jet Head, Method Of Producing Piezoelectric Actuator, And Method Of Producing Ink-Jet Head
US20140161972A1 (en) * 2012-12-09 2014-06-12 National Sun Yat-Sen University Method for forming conductive film at room temperature

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US28820A (en) * 1860-06-19 wright
BE590159A (fr) * 1959-04-27
AT223209B (de) * 1959-04-27 1962-09-10 Ici Ltd Verfahren zur Herstellung eines Verbundkörpers, der aus einem Trägerkörper aus Titan und einem Überzug aus Platinmetallen besteht
USRE28820E (en) 1965-05-12 1976-05-18 Chemnor Corporation Method of making an electrode having a coating containing a platinum metal oxide thereon
US3778307A (en) * 1967-02-10 1973-12-11 Chemnor Corp Electrode and coating therefor
GB1195871A (en) * 1967-02-10 1970-06-24 Chemnor Ag Improvements in or relating to the Manufacture of Electrodes.
US3562008A (en) * 1968-10-14 1971-02-09 Ppg Industries Inc Method for producing a ruthenium coated titanium electrode
US4070504A (en) * 1968-10-29 1978-01-24 Diamond Shamrock Technologies, S.A. Method of producing a valve metal electrode with valve metal oxide semi-conductor face and methods of manufacture and use
LU60168A1 (fr) * 1970-01-09 1971-09-22
US3684543A (en) * 1970-11-19 1972-08-15 Patricia J Barbato Recoating of electrodes
US3924025A (en) * 1972-02-02 1975-12-02 Electronor Corp Method of making an electrode having a coating of cobalt metatitanate thereon
US4032427A (en) * 1975-11-03 1977-06-28 Olin Corporation Porous anode separator
JPS5393179A (en) * 1977-01-27 1978-08-15 Tdk Corp Electrode for electrolysis and its manufacture

Also Published As

Publication number Publication date
DE3004080C2 (de) 1986-03-20
DE3004080A1 (de) 1981-08-13
US4431686A (en) 1984-02-14
EP0033363A1 (fr) 1981-08-12

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