FR2498086A2 - Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas - Google Patents

Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas Download PDF

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FR2498086A2
FR2498086A2 FR8100936A FR8100936A FR2498086A2 FR 2498086 A2 FR2498086 A2 FR 2498086A2 FR 8100936 A FR8100936 A FR 8100936A FR 8100936 A FR8100936 A FR 8100936A FR 2498086 A2 FR2498086 A2 FR 2498086A2
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oxide
exhaust gas
catalyst
motor vehicle
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FR2498086B2 (en
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Jean-Louis Barnabe
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Renault SAS
Regie Nationale des Usines Renault
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Renault SAS
Regie Nationale des Usines Renault
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/8993—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with chromium, molybdenum or tungsten
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/85—Chromium, molybdenum or tungsten
    • B01J23/86—Chromium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/892—Nickel and noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/8946—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali or alkaline earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Health & Medical Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
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Abstract

This is an addn. to 79.16049, which described an alloy based on Fe, Cr and Ni, and contg. carbon plus a Pt gp. metal. The surface of the alloy is subjected to intergranular corrosion by an acid to cause microfissures and to expose microcrystals of the Pt. gp. metals. The novelty in the present invention is that the catalyst is stabilised by adding Th, Sr, Hf, Be, and/or Ti. The stabilising addns. are pref. added by impregnation using a soln. of soluble salts of the addns., together with similar cerium salts using a ratio above 2:1. The catalyst pref. contains by wt. 10% max., esp. 0.1-5% of the addns. The addns. pref. form max. 50%, esp. 0.5-25% of the surface oxides on the catalyst. As compared with the parent patent, the performance of the catalyst is improved at 650-1000 deg. C. Used for treating motor vehicle exhaust gas.

Description

Alliage métallique à activité catalytique élevée.Metal alloy with high catalytic activity.

La présente addition se rapporte à l'amélioration de l'activité catalytique de l'alliage métallique selon la demande principale 79 16 049, notamment lors de son fonctionnement à température élevée, c'est-àdire supérieure à 650 OC et pouvant atteindre 1 000 OC. The present addition relates to the improvement of the catalytic activity of the metal alloy according to the main application 79 16 049, in particular during its operation at high temperature, that is to say greater than 650 OC and up to 1000 OC.

Dans la demande principale ci-dessus, on décrit un catalyseur, notamment destiné à dépolluer les gaz d'échappement des véhicules automobiles, obtenu sous forme d'alliage métallique actif.In the main application above, there is described a catalyst, in particular for cleaning the exhaust gas of motor vehicles, obtained in the form of active metal alloy.

Il est essentiellement constitué d'une base réfractaire, comportant en particulier du fer, du chrome et du nickel, incluant dans sa masse du carbone et au moins un métal de la mine du platine. Sa surface a été en outre soumise à une corrosion intergranulaire acide, entraî- nant sa microfissuration ainsi que l'apparition de microcristaux de platinoides.It consists essentially of a refractory base, including in particular iron, chromium and nickel, including in its mass of carbon and at least one metal of the platinum mine. Its surface was further subjected to acidic intergranular corrosion, resulting in its microcrystallization and the appearance of microcrystals of platinoids.

Cependant, bien que l'activité catalytique du produit ci-dessus soit très bonne à l'état neuf, on a constaté qu'elle diminuait sensiblement lors de son fonctionnement à une température supérieure à 750 OC.However, although the catalytic activity of the above product is very good in the new state, it has been found that it decreases substantially during its operation at a temperature above 750 OC.

La présente invention a pour but de pallier l'inconvénient ci-dessus; on stabilise ainsi le catalyseur selon l'invention par adjonction de certains métaux, tels que le Thorium, l'Hafnium, le Strontium, le
Berylium, etc. dans les conditions ci-dessous.The present invention aims to overcome the above disadvantage; the catalyst according to the invention is thus stabilized by the addition of certain metals, such as Thorium, Hafnium, Strontium,
Berylium, etc. under the conditions below.

Selon un mode préféré de réalisation de l'invention, on imprègne le catalyseur selon le brevet principal d'une solution de nitrates ou de composé solubles de Thorium et de Cérium dans un rapport de Th 02 supérieur à 2. Ce 02
Cette imprégnation se produit dans la couche superficielle poreuse, d'oxydes de fer, de nickel et de chrome, en des teneurs maximales de 10% en poids de la masse delélément catalytique , ou de 50 50 en poids des oxydes présents dans la couche superficielle du catalyseur.According to a preferred embodiment of the invention, the catalyst according to the main patent is impregnated with a solution of nitrates or soluble compounds of Thorium and Cerium in a ratio of Th 02 greater than 2. This
This impregnation occurs in the porous surface layer, of iron oxides, of nickel and of chromium, at a maximum content of 10% by weight of the mass of the catalytic element, or 50% by weight of the oxides present in the surface layer. catalyst.

Ceci permet alors de stabiliser l'activité du produit résultant
à 750-800 OC, températures couramment atteintes dans les conditions de fonctionnement normales du véhicule, à la sortie du collecteur d'échappement. This then makes it possible to stabilize the activity of the resulting product
at 750-800 OC, temperatures commonly reached under normal vehicle operating conditions at the outlet of the exhaust manifold.

On constate également que même après un test de vieillissement artificiel prolongé à haute température (: 24h à 1000 C), le produit stabilisé dans les conditions ci-dessus conserve une activité catalyticlue
beaucoup plus élevée que celle du produit qui n'en contient pas n ou qui contient des oxydes d'autres métaux tels que l'aluminium, le zinconium ou des lanthanides.It is also found that even after an artificial aging test prolonged at high temperature (24h to 1000 C), the product stabilized under the above conditions retains catalytic activity.
much higher than the product that does not contain n or contains oxides of other metals such as aluminum, zinconium or lanthanides.

Il en est de même pour l'adjonction dans des conditions analogues d'oxydes de Strontium, d'Hafmium, de Bérylium et de Titane.It is the same for the addition under similar conditions of oxides of Strontium, Hafmium, Beryllium and Titanium.

L'amélioration apportée par l'adjonction de ces oxydes réfractaires résulte de la combinaison de leur activité catalytique propre, de leur température de fusion très élevée, de leur faible réactivité vis à vis des oxydes de fer, de nickel et de chrome, ainsi que de leur surface spécifique notable.The improvement provided by the addition of these refractory oxides results from the combination of their own catalytic activity, their very high melting temperature, their low reactivity with respect to the iron, nickel and chromium oxides, as well as their specific surface area.

On constate qu'ils réduisent le frittage des oxydes superficiels dont ils accroissent en outre la porosité, la surface, et ne réagissent pas avec l'oxyde de rhodium ni avec l'oxyde de fer comme le fait l'alumine.It is found that they reduce the sintering of surface oxides which they further increase the porosity, the surface, and do not react with rhodium oxide or with iron oxide as does alumina.

Par ailleurs, ils favorisent la formation d'oxydes de fer actifs, du type Fe O ou Fe2 3 au détriment des oxydes inactifs tels que Fe3 O 23 34
On notera l'intérêt particulier du catalyseur stabilisé avec de l'oxyde de Strontium, car il retrouve un niveau d'activité excellent, même après vieillissement/par 0nc0tionnement soit en mélange riche, soit en mélange pauvre, à température comprise entre 400 et 750 tC. Moreover, they promote the formation of active iron oxides, of the Fe 0 or Fe 2 3 type, to the detriment of inactive oxides such as Fe 3 O 23
Note the particular interest of the catalyst stabilized with Strontium oxide, because it found an excellent level of activity, even after aging / by operation either in rich mixture or lean mixture, at a temperature between 400 and 750 tC.

Un autre mode de réalisation de l'invention consiste à stabiliser le catalyseur selon la demande de brevet principale, en introduisant les métaux du type Thorium, Hafnium, Strontium, Berylium et Titane directement comme additif dans l'alliage métallique de base, à même titre que les platinoides.Another embodiment of the invention consists in stabilizing the catalyst according to the main patent application, by introducing the metals of the Thorium, Hafnium, Strontium, Berylium and Titanium type directly as an additive into the base metal alloy, in the same way than the platinoides.

Les tableaux ci-dessous rapportent, à titre d'exemples non limitatifs, quelques résultats numériques relatifs aux catalyseurs traités selon l'invention, obtenus dans des conditions d'essai usuelles. The tables below give, by way of nonlimiting examples, some numerical results relating to the catalysts treated according to the invention, obtained under standard test conditions.

1) On utilise des produits neufs, stabilisés par fonctionnement pendant 2h
à 750 OC dans une atmosphère constituant un mélange stoechio
métrique.1) We use new products, stabilized by operation for 2 hours
at 750 OC in an atmosphere constituting a stoichi
metric.

On considèrera l'efficacité E de la transformation des quantités pondérales des différents polluants au cours de la catalyse.We will consider the efficiency E of the transformation of the weight quantities of the different pollutants during the catalysis.

Donc, E = 100 % dans le cas de la dépollution totale.

Figure img00030001
Therefore, E = 100% in the case of total depollution.
Figure img00030001

<tb><Tb>

<SEP> Températures
<tb> Additifs <SEP> d'essai <SEP> entre <SEP> E <SEP> CO <SEP> % <SEP> E <SEP> HC <SEP> % <SEP> E <SEP> NOx <SEP> %
<tb> <SEP> Néant <SEP> 2 <SEP> et <SEP> 500 <SEP> C <SEP> 28 <SEP> 32 <SEP> 36
<tb> <SEP> 3 <SEP> et <SEP> 600 <SEP> C <SEP> 66 <SEP> 66 <SEP> 69
<tb> <SEP> Th <SEP> O2 <SEP> + <SEP> Ce <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 51 <SEP> 50 <SEP> 46
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 81 <SEP> 80 <SEP> 76
<tb> <SEP> Hf <SEP> O2 <SEP> + <SEP> Ce <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 57 <SEP> 55 <SEP> 58
<tb> <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 88 <SEP> 87 <SEP> 89
<tb> <SEP> Sr <SEP> O <SEP> + <SEP> Ce <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 53 <SEP> 52 <SEP> 56
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 86 <SEP> 85 <SEP> 89
<tb> 2) Produit vieilli 24h à 1000 OC, puis réactivé à 750 OC, pendant 2 h
en mélange riche.

Figure img00030002
<SEP> Temperatures
<tb><SEP> Test Additives <SEP> Between <SEP> E <SEP> CO <SEP>% <SEP> E <SEP> HC <SEP>% <SEP> E <SEP> NOx <SEP>%
<tb><SEP> Nil <SEP> 2 <SEP> and <SEP> 500 <SEP> C <SEP> 28 <SEP> 32 <SEP> 36
<tb><SEP> 3 <SEP> and <SEP> 600 <SEP> C <SEP> 66 <SE> 66 <SEP> 69
<tb><SEP> Th <SEP> O2 <SEP> + <SEP> This <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 51 <SEP> 50 <SEP> 46
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 81 <SEP> 80 <SEP> 76
<tb><SEP> Hf <SEP> O2 <SEP> + <SEP> This <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 57 <SEP> 55 <SEP> 58
<tb><SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 88 <SEP> 87 <SEP> 89
<tb><SEP> Sr <SEP> O <SEP> + <SEP> This <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 53 <SEP> 52 <SEP> 56
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 86 <SEP> 85 <SEP> 89
<tb> 2) Product aged 24h at 1000 OC, then reactivated at 750 OC, for 2 h
in rich mixture.
Figure img00030002

<tb><Tb>

Additifs <SEP> Température
<tb> <SEP> d'essai <SEP> entre <SEP> E <SEP> CO <SEP> % <SEP> E <SEP> HC <SEP> % <SEP> E <SEP> NOx <SEP> %
<tb> Néant <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 19 <SEP> 21 <SEP> 28
<tb> <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 39 <SEP> 48 <SEP> 55
<tb> <SEP> Th <SEP> O <SEP> + <SEP> Ce <SEP> O <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> : <SEP> 22 <SEP> : <SEP> 30 <SEP> : <SEP> 34
<tb> : <SEP> 2 <SEP> : <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> : <SEP> 52 <SEP> : <SEP> 63 <SEP> : <SEP> 64
<tb> ------:---------:------:-----:---
<tb> 11f <SEP> O2 <SEP> + <SEP> Ce <SEP> O2 <SEP> : <SEP> 2 <SEP> - <SEP> 500 <SEP> 0C <SEP> : <SEP> 17 <SEP> : <SEP> 19 <SEP> 25
<tb> <SEP> Hf <SEP> O2 <SEP> + <SEP> Ce <SEP> O2 <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 40 <SEP> 51 <SEP> 53
<tb> Sr <SEP> O <SEP> + <SEP> Ce <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 35 <SEP> 37 <SEP> 45
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 62 <SEP> 69 <SEP> 73
<tb>
A la lecture des tableaux ci-dessus, on constate donc bien une sen- sible amélioration du pourcentage de transformation des gaz polluants, après introduction des additifs dans les conditions de l'invention
Des essais ont par ailleurs démontré qu'on obtenait des résultats analogues si, toutes choses étant égales par ailleurs, on remplaçait totalement ou partiellement dans le catalyseur de base selon le brevet principal les inclusions de carbone par du silicium. Additives <SEP> Temperature
<tb><SEP> Test <SEP> Between <SEP> E <SEP> CO <SEP>% <SEP> E <SEP> HC <SEP>% <SEP> E <SEP> NOx <SEP>%
<tb> Nil <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 19 <SEP> 21 <SEP> 28
<tb><SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 39 <SEP> 48 <SEP> 55
<tb><SEP> Th <SEP> O <SEP> + <SEP> This <SEP> O <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP>: <SEP> 22 <SEP> : <SEP> 30 <SEP>: <SEP> 34
<tb>: <SEP> 2 <SEP>: <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP>: <SEP> 52 <SEP>: <SEP> 63 <SEP>: <SEP > 64
<tb> ------: ---------: ------: -----: ---
<tb> 11f <SEP> O2 <SEP> + <SEP> This <SEP> O2 <SEP>: <SEP> 2 <SEP> - <SEP> 500 <SEP> 0C <SEP>: <SEP> 17 <SEP >: <SEP> 19 <SEP> 25
<tb><SEP> Hf <SEP> O2 <SEP> + <SEP> This <SEP> O2 <SEP> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 40 <SEP> 51 <SEP> 53
<tb> Sr <SEP> O <SEP> + <SEP> This <SEP> O2 <SEP> 2 <SEP> - <SEP> 500 <SEP> C <SEP> 35 <SEP> 37 <SEP> 45
<tb> 3 <SEP> - <SEP> 600 <SEP> C <SEP> 62 <SEP> 69 <SEP> 73
<Tb>
On reading the above tables, there is therefore a significant improvement in the percentage of conversion of the polluting gases, after introduction of the additives under the conditions of the invention.
Tests have furthermore demonstrated that analogous results are obtained if, all things being equal, the inclusions of carbon with silicon are completely or partially replaced in the base catalyst according to the main patent.

Claims (5)

REVENDICATIONS selon la revendication 1 du Brevet Principal 1. Alliage métallique à activité catalytique élevée/,utilisable notamment pour les gaz d'échappement de véhicules automobiles, essentiellement constitué d'une base réfractaire, en particulier à base de fer, de chrome et de nickel, dans laquelle on inclut du carbone ainsi qu'au moins un métal de la mine du platine, dont la surface a été soumise à une corrosion intergranulaire acide entrainant sa microfissuration ainsi que l'apparition de microcristaux de platinoides, caractérisé par le fait que l'on stabilise le catalyseur ci-dessus par l'ajonc tion de certains métaux du type Thorium, Strontium, Hafnium, Bérylium ou Titane. according to claim 1 of the main patent 1. High catalytically active metal alloy /, usable in particular for motor vehicle exhaust gas, consisting essentially of a refractory base, in particular based on iron, chromium and nickel, in which carbon is included as well as at least one metal of the platinum mine, the surface of which has been subjected to intergranular acid corrosion causing its microcrystallization as well as the appearance of microcrystals of platinoids, characterized in that the the above catalyst is stabilized by the addition of certain metals of the Thorium, Strontium, Hafnium, Beryllium or Titanium type. 2. Alliage métallique selon la revendication 1, caractérisé en ce que l'adjonction est effectuée par l'imprégnation à l'aide d'une solution d'une part de composés solubles desdits métaux et d'autre part de sels analogues de Cérium, dans un rapport supérieur à 2.2. Metallic alloy according to claim 1, characterized in that the addition is carried out by impregnation with the aid of a solution on the one hand of soluble compounds of said metals and on the other hand of similar salts of cerium, in a ratio greater than 2. 3. Alliage métallique selon les revendications 1 et 2, caractérisé en ce que la teneur de l'apport obtenu par l'imprégnation représente au oeaximumîO% en poids de la masse totale de l'alliage métallique, de préférence comprise entre 0,1 et 5 %.3. Metallic alloy according to claims 1 and 2, characterized in that the content of the input obtained by the impregnation represents at oeaximumî0% by weight of the total mass of the metal alloy, preferably between 0.1 and 5%. 4. Alliage métallique selon les revendications 1 et 2, caractérisé en ce que la teneur de l'apport obtenu par l'imprégnation représente au maximum 50 % en poids des oxydes présents dans la couche superficielle de l'alliage métallique, de préférence comprise entre 0,5 et 25 ,ó. 4. Metallic alloy according to claims 1 and 2, characterized in that the content of the input obtained by the impregnation represents at most 50% by weight of the oxides present in the surface layer of the metal alloy, preferably between 0.5 and 25, ó. 5. Alliage métallique selon l'une quelconque des revendications précédentes, caractérisé en ce que l'on substitue totalement ou partiellement aux inclusions de carbone des inclusions de silicium. 5. Metallic alloy according to any one of the preceding claims, characterized in that the silicon inclusions are totally or partially substituted for the inclusions of carbon.
FR8100936A 1979-06-22 1981-01-20 Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas Granted FR2498086A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR8100936A FR2498086A2 (en) 1979-06-22 1981-01-20 Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7916049A FR2459681A1 (en) 1979-06-22 1979-06-22 Highly catalytic alloy - based on iron nickel and chromium and contg. carbon and platinum gp. metal
FR8100936A FR2498086A2 (en) 1979-06-22 1981-01-20 Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas

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FR2498086A2 true FR2498086A2 (en) 1982-07-23
FR2498086B2 FR2498086B2 (en) 1983-02-18

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FR8100936A Granted FR2498086A2 (en) 1979-06-22 1981-01-20 Alloy with high catalytic activity - stabilised by cpds. such as thorium di:oxide and cerium di:oxide, and used for treating motor vehicle exhaust gas

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2194479A1 (en) * 1972-08-04 1974-03-01 Engelhard Min & Chem Catalyst system for oxidn of combustion gases - contg oxides of copper, chromium and a rare earth metal, and platinum or palladium on catalytically active, refractory carrier
US3849511A (en) * 1970-10-07 1974-11-19 Petro Tex Chem Corp Oxidative dehydrogenation with manganese ferrite catalyst
FR2340768A2 (en) * 1976-02-10 1977-09-09 Renault Prodn. of catalytic supports for exhaust gas purification - by sintering metal fibres on a removable perforated substrate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849511A (en) * 1970-10-07 1974-11-19 Petro Tex Chem Corp Oxidative dehydrogenation with manganese ferrite catalyst
FR2194479A1 (en) * 1972-08-04 1974-03-01 Engelhard Min & Chem Catalyst system for oxidn of combustion gases - contg oxides of copper, chromium and a rare earth metal, and platinum or palladium on catalytically active, refractory carrier
FR2340768A2 (en) * 1976-02-10 1977-09-09 Renault Prodn. of catalytic supports for exhaust gas purification - by sintering metal fibres on a removable perforated substrate

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