JP2011521104A - Process for producing CXHYOZ type compounds by reduction of carbon dioxide (CO2) and / or carbon monoxide (CO) - Google Patents

Abstract

The present invention is introduced under pressure into an anode chamber (32) of an electrolytic cell (30) comprising a proton conducting membrane (31) made from a material capable of introducing protonated species into this membrane under steam. Water injected in the form of steam is oxidized at the anode (32) and migrates to said membrane within this same membrane, and carbon dioxide and / or carbon monoxide is obtained. Regarding the method of generating protonated species that are reduced at the surface of the cathode (33) in the form of reducible reactive hydrogen atoms, said method comprises the following steps: in the cathode chamber (33) of the electrolytic cell (30) Injecting CO ₂ and / or CO under pressure into the cathode chamber, and reducing the CO ₂ and / or CO injected into the cathode chamber (33) by the generated reactive hydrogen atoms. ₂ and / or CO is _x H _y O _z type compounds (a x ≧ 1, y is 0 to 2x + 2, z is a is 0 to 2x) and forming.

Description

The present invention is especially highly reactive hydrogen species generated by electrolysis of water, carbon dioxide (CO ₂₎ and / or C _x H _y O _z type compounds by reduction of the carbon monoxide (CO) (especially x ≧ 1, y is 0 to 2x + 2, and z is 0 to 2x).

At present, ceramic conductive membranes are the subject of much research to improve their performance, and these membranes have particularly interesting applications, especially in the following areas. Ie:
- electrolysis of water at a high temperature for producing hydrogen - C _x H _y O _z type compounds (a x ≧ 1, y is 0 to 2x + 2, z is a is 0 to 2x) to obtain Treatment of carbon-containing gases (CO ₂ , CO) by electrochemical hydrogenation.

Currently, hydrogen (H ₂ ) appears to be a very interesting energy carrier and is considered to be increasingly important for treating petroleum, oils and lubricants among other materials, eventually Advantageously, its reserves may be used in place of petroleum and fossil energy that will decline sharply over the coming decades. However, from this standpoint, it is necessary to develop manufacturing methods.

  Obviously, many hydrogen production methods have been described in various sources, but many of these methods have been found to be unsuitable for large-scale industrial production of hydrogen.

In this case, for example, hydrogen is synthesized by steam reforming of hydrocarbon. One of the main problems with this synthesis route is that it produces a significant amount of CO ₂ type greenhouse gases as a by-product. In fact, it produces 8 to 10 tons of CO ₂ to produce 1 ton of hydrogen.

  Therefore, the following two remain as future issues. That is, to look for new energy carriers that are useful without harming our environment, such as hydrogen, and to reduce the amount of carbon dioxide.

  The technical and economic evaluation of industrial methods now considers the latter data. However, it is essentially a sequestration within a crack that does not necessarily correspond to an old oil reservoir, in particular an underground sequestration, and eventually it can be dangerous.

  It seems advisable to recycle this carbon dioxide in the form of compounds useful in the chemical field or in the energy production field. The energy required for this conversion is, for example, electricity from nuclear power, in particular from nuclear reactors such as HTR “high temperature reactor” type reactors or EPR® European pressurized water reactors.

  A promising route for the industrial production of hydrogen is for example the technique known as steam electrolysis at high temperatures (EHT), medium temperatures, typically above 200 ° C., or even intermediate temperatures between 200 ° C. and 1000 ° C. .

  Two steam electrolysis production methods are currently known.

The first method shown in FIG. 1 utilizes an electrolyte capable of transporting O ²⁻ ions and generally operating at temperatures between 750 ° C. and 1000 ° C.

More precisely, FIG. 1 schematically illustrates an electrolytic cell 1 comprising a ceramic membrane 2 that is a conductor of O ²⁻ ions, ensuring that the electrolyte functions to separate the anode 3 and the cathode 4. Show.

によって陰極４の表面に水素Ｈ₂およびイオンＯ^2-（クレーガー＝ビンクの表記法では

）を形成する。 By applying a potential difference between the anode 3 and the cathode 4, the H ₂ O vapor on the cathode 4 side is reduced. This reduction is a reaction:

To the surface of the cathode 4 with hydrogen H ₂ and ions O ²⁻ (in the notation of Crager-Bink)

).

が電解質２中を移動して陽極３の表面において酸素Ｏ₂を形成し、電子ｅが酸化反応：

によって放出される。 O ^2- ions, more precisely oxygen vacancies

Moves through the electrolyte ₂ to form oxygen O ₂ on the surface of the anode 3, and the electrons e oxidize:

Released by.

  Therefore, from the output of the electrolytic cell 1, the first method can generate an oxygen-anode chamber- and a hydrogen-cathode chamber mixed with steam.

  The second method shown in FIG. 2 is capable of transporting protons and operates at a lower temperature, generally 200 ° C. to 800 ° C., than required for the first method described above. An electrolyte that can be used is used.

  More precisely, this FIG. 2 schematically shows an electrolytic cell 10 containing a proton conducting ceramic membrane 11 to ensure that the electrolyte functions to separate the anode 12 and the cathode 13.

）を形成し、この反応は、式：

によって電子ｅ^-を放出する。 By applying a potential difference between the anode 12 and the cathode 13, the H ₂ O vapor on the anode side 12 is oxidized. Therefore, the vapor injected into the anode 12 is oxidized and oxygen O ₂ and H ⁺ ions (or in the notation of Crager-Bink)

This reaction forms the formula:

To release electrons e ⁻ .

）は、電解質１１中を移動して式：

によって陰極１３の表面に水素Ｈ₂を形成する。 H ⁺ ion (or Crager-Bink notation

) Moves through the electrolyte 11 and has the formula:

Thus, hydrogen H ₂ is formed on the surface of the cathode 13.

  This method thus provides a high purity hydrogen-cathode chamber- and oxygen-anode chamber mixed with steam from the output of the electrolyzer 10.

（またはクレーガー＝ビンクの表記法では

Ｅｌｅｃｔｒｏｄｅ：電極
）である中間化合物の形成を経る。これらの種が高反応性であるとき、それらは通常、式：

Ｅｌｅｃｔｒｏｄｅ：電極
によって再結合して水素Ｈ₂を形成する。 More precisely, the formation of H ₂ is caused by hydrogen atoms and / or hydrogen atom radicals absorbed at the surface of the cathode by variable energy and degree of interaction.

(Or in Crager-Bink notation

An intermediate compound which is an Electrode (electrode) is formed. When these species are highly reactive, they usually have the formula:

Electrode: Recombines with an electrode to form hydrogen H ₂ .

  The present invention aims to reduce the amount of carbon dioxide present, for example by recycling the carbon dioxide in the form of compounds useful in the chemical or energy production field.

For this purpose, the present invention relates to water vapor injected under pressure into the anode chamber of an electrolytic cell comprising a proton conducting membrane made from a material capable of introducing protonated species into the membrane under steam. A method for electrolysis, wherein the oxidation of water injected in the form of a vapor is carried out at the anode and migrates into said membrane within this same membrane, so that carbon dioxide CO ₂ and / or carbon monoxide CO is removed. Proposed is a method for generating protonated species that are reduced at the surface of the cathode in the form of reactive hydrogen atoms that can be reduced, said method comprising the following steps:
Injecting CO ₂ and / or CO under pressure into the cathode chamber of the electrolytic cell;
The generated reactive hydrogen atoms reduce the CO ₂ and / or CO injected into the cathode chamber so that the CO ₂ and / or CO is of the C _{x Hy} O _z type Forming a compound (x ≧ 1, y is 0 to 2x + 2, and z is 0 to 2x).

（またはクレーガー＝ビンクの表記法では

Ｅｌｅｃｔｒｏｄｅ：電極
）を指すと理解される。 As explained above, reactive hydrogen atoms are hydrogen atoms and / or hydrogen atom radicals absorbed at the surface of the cathode by variable energy and degree of interaction.

(Or in Crager-Bink notation

Electrode: an electrode).

  The present invention results from the observation that the second method described above generates highly reactive hydrogen (especially hydrogen atoms and / or hydrogen atom radicals absorbed at the surface of the electrode) at the cathode of the electrolytic cell.

Ｅｌｅｃｔｒｏｄｅ：電極
は、反応：

Ｅｌｅｃｔｒｏｄｅ：電極
によって陰極の表面において形成される。 These highly reactive hydrogen atoms

Electrode: electrode reacts:

Electrode: formed on the surface of the cathode by an electrode.

Ｅｌｅｃｔｒｏｄｅ：電極
が電極上の炭素化合物と反応して、Ｃ_xＨ_yＯ_z（ｘ≧１であり、ｙが０〜２ｘ＋２であり、ｚが０〜２ｘである）タイプの還元された二酸化炭素および／または一酸化炭素化合物を生じる。 In fact, highly reactive hydrogen when CO ₂ and / or CO is present on the cathode side

Electrode: reduced carbon dioxide of the type C _x H _y O _z (x ≧ 1, y is 0-2x + 2, z is 0-2x) when the electrode reacts with the carbon compound on the electrode And / or carbon monoxide compounds.

By way of example, these compounds include paraffin C _n H _{2n + 2} , olefin C _2n H _2n , alcohol C _n H _{2n + 2} OH or C _n H _2n-1 OH, aldehydes and ketones C _n H _2n O, acid C _{n-1 H2n + 1} COOH (n ≧ 1).

  Thus, the present invention is capable of electrolyzing steam by comprehensive electroreduction of carbon dioxide and / or carbon monoxide as will be described next.

In addition, the method of the present invention may exhibit one or more of the following characteristics, considered individually or in all technically possible combinations.
The method comprises the step of controlling the properties of a C _x H _y O _z type compound formed by a voltage-current pair applied to the cathode;
The method comprises the step of utilizing a proton conducting membrane that is impermeable to the diffusion of oxygen O ₂ and H ₂ and allows the injection of protonated species into the membrane under vapor pressure.
-This method consists of defective perovskites, non-stoichiometric perovskites and / or doped perovskites of the general formula ABO ₃ , fluorite, pyrochlore A ₂ B ₂ X ₇ , apatite Me ₁₀ (XO ₄ ) ₆ Y ₂ , Oxyapatite Me ₁₀ (XO ₄ ) ₆ O ₂ structure, Hydroxyapatite Me ₁₀ (XO ₄ ) ₆ (OH) ₂ structure, silicate, aluminosilicate (phyllosilicate or zeolite) structure, silicate or phosphate grafted with oxyacid Using a grafted silicate type proton conducting membrane.
The method comprises the step of reducing its thickness in order to increase its mechanical strength by utilizing an electrolyte supported by or by the cathode.
The method comprises the step of utilizing the relative partial pressure of the vapor above 1 bar and below the breaking pressure of the joint, the latter being at least 100 bar and above.
The relative partial pressure of the steam is preferably greater than 50 bar;
The relative pressure of CO ₂ and / or CO is 1 bar or more and below the breaking pressure of the joined body, the latter being at least 100 bar or more.
The electrolysis temperature is from 200 ° C. to 800 ° C., preferably from 350 ° C. to 650 ° C.
The porous structure electrode is a mixture of electronic and ionic conducting ceramic-metal materials or “ceramic” electrodes;
-For the cathode, the ceramic-metal material is preferably a metal such as cobalt, copper, molybdenum, silver, iron, zinc, noble metals (gold, platinum, palladium) and / or transition elements in the nature of the dispersed metal. A metal and / or metal alloy, which is a ceramic compatible with the electrolyte,
-For the anode, the ceramic-metal material is a ceramic compatible with the electrolyte, in which the properties of the dispersed metal are advantageously metal alloys or passivatable metals.

The present invention also electrolyzes water vapor introduced under pressure into the anode chamber of an electrolytic cell comprising a proton conducting membrane made from a material that allows the injection of protonated species into the membrane under steam after oxidation. A steam electrolysis device for
An electrolyte in the form of an ion-conducting membrane made from said material that allows the injection of protonated species into the membrane under the influence of water pressure;
-An anode;
-A cathode;
A steam electrolyzer comprising a generator capable of generating a current to apply a potential difference between the anode and the cathode, comprising:
-Means for introducing steam under pressure into the electrolyte via the anode;
-Means for injecting CO ₂ and / or CO under pressure into the cathode chamber of the electrolytic cell;
- characterized in that the method according to one of the preceding embodiments and means for reducing the introduced CO ₂ and / or CO in the cathode chamber.

The apparatus of the present invention may also exhibit one or more of the following characteristics, considered individually or in all technically possible combinations.
The material that allows the injection of protonated species is impermeable to O ₂ and H ₂ gases.
The material enabling the injection of protonated species has a densification level of more than 88%, preferably at least 94%.
The material enabling the implantation of protonated species is an oxygen atom deficient oxide such as an oxygen deficient perovskite which acts as a proton conductor. In this case, the oxygen atom deficient oxide may exhibit stoichiometric spacing and / or may be doped.

  Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings, which are illustrative and not limiting.

It is a simplified diagram of a steam electrolysis tank. It is a simplified diagram of a steam electrolysis tank. FIG. 2 is a simplified diagram of a steam electrolyzer that performs total electrolytic reduction of CO ₂ and / or CO.

FIG. 3 schematically shows an embodiment of an electrolyzer for the production of hydrogen for carrying out the overall electrolytic reduction process of CO ₂ and / or CO according to the invention.

This electrolysis apparatus has a structure similar to that of the apparatus of FIG. Therefore it is
-An anode 32;
A cathode 33;
-Electrolyte 31;
A generator 34 that ensures a potential difference between the anode 32 and the cathode 33;
Means 35 for allowing introduction into the membrane 31 via the cathode 33 under the pressure of steam pH ₂ O (the relative partial pressure of the steam is not less than 1 bar and not more than the breaking pressure of the assembly, this latter being at least 100 bar; It is above.

According to the invention, the apparatus also includes means 36 that allow introduction into the cathode chamber 33 under gas pressure (pCO ₂ and / or CO).

Steam injection is performed by means 35 on the anode 32 side, while gas CO ₂ and / or CO injection is performed by means 36 on the cathode 33 side.

の形の）Ｈ⁺イオンが図２を用いて説明された方法と同様な方法によって発生される間に電子を放出することによって酸化される。 In the anode 32, the water is (

H ⁺ ions (in the form of) are oxidized by releasing electrons while they are generated by a method similar to that described with reference to FIG.

These H ⁺ ions move through the electrolyte 31, and CO ₂ and / or CO type carbon compounds react with these H ⁺ ions at the cathode 33 to form C _x H _y O _z type compounds (when x ≧ 1). And y is 0-2x + 2 and z is 0-2x) and water is formed at the cathode.

Ｅｌｅｃｔｒｏｄｅ：電極 In particular, chemical reactions for various reactions can be written as:

Electrode: Electrode

Ｅｌｅｃｔｒｏｄｅ：電極
として記載することができる。 Since the nature of the compound formed depends on the working conditions, therefore, the total formation reaction of C _x H _y O _z

Electrode: can be described as an electrode.

The nature of the C _x H _y O _z compounds synthesized in the cathode, for example, depend on many process parameters such as gas pressure, voltage and current pairs applied to the working temperature T1 and a cathode as described below .

Regarding the gas pressure, the relative pressure of CO ₂ and / or CO is 1 bar or more and below the breaking pressure of the joint, the latter being at least 100 bar or more.

  Here, it is pointed out that the term relative pressure means the introduction pressure relative to the atmospheric pressure.

  It is pointed out that either a gas stream containing only steam or a gas stream partially containing steam can be used. Thus, in some cases, the term “partial pressure” means the total pressure of a gas stream when the gas stream is composed solely of steam, or the partial pressure of the steam when it contains a gas other than steam. Either one.

  In addition, the total pressure applied to the cathode chamber or the anode chamber can be compensated for the total pressure of the other chamber, has a pressure difference between the two chambers, and its fracture resistance is very low. In some cases, the membrane / electrode support assembly is prevented from breaking.

With respect to the working temperature T1 of the device, this depends on the type of material utilized for the membrane 31. In any case, this temperature is above 200 ° C., generally below 800 ° C., or even below 600 ° C. This working temperature corresponds to the conduction ensured by H ⁺ protons.

The working temperature T1 of the apparatus is in the range of 200 to 800 ° C. depending on the properties of the C _x H _y O _z carbon compound to be generated.

  Indeed, a wide variety of compounds can be obtained, such as methane, methanol, formaldehyde, carboxylic acids (such as formic acid) and other compounds with long chains, which can also form synthetic fuels.

Ｅｌｅｃｔｒｏｄｅ：電極 For example, the following reaction can be carried out at the cathode.

Electrode: Electrode

Ｈｙｄｒｏｇｅｎａｔｉｏｎ：水素化 It should be noted that with respect to the voltage / current pair applied to the cathode, the nature of the carbon compound formed also depends on this voltage. In fact, as shown in the following scheme, when the cathode medium becomes more reducible (low redox potential E), the generated carbon compound is more hydrogenated (R is an alkyl group, for example).

Hydrogenation: Hydrogenation

  For advantageous embodiments of these reactions, it is necessary to have an electrode that exhibits a number of three contact points, ie, points or contact surfaces between the ionic conductor, the electronic conductor and the gas phase.

  For example, the electrode considered is preferentially a ceramic-metal material formed by a mixture of an ion conducting ceramic and an electron conducting metal.

  However, the use of “all ceramic” electron conducting electrodes rather than ceramic-metal materials may also be considered.

A given electrolyte may be an O ² -proton or ionic conductor depending on the temperature and pressure of the vapor applied.

However, the use of a proton conducting membrane generates hydrogen (more or less in the form of hydrogen atoms absorbed at the surface of the cathode) that is much more reactive than H ₂ hydrogen (or dihydrogen), and therefore (of H ₂ Allows better hydrogenation of CO ₂ and CO compared to conventional hydrogenation methods (in the presence).

In addition, the use of H ⁺ ion conducting membranes that operate at moderate temperatures allows the synthesis of C _x H _y O _z type complex compounds (x, y and z are greater than 1), while operating at higher temperatures. Use of the O ² -conducting membrane preferentially generates CO, a product that is stable at high temperatures.

The purpose of the studies performed is to obtain the maximum yield of hydrogen production and / or CO ₂ and / or hydrogenation of CO. In order to do this, the majority of the current utilized must be involved in the Faraday process, i.e. it must be utilized for the reduction of water and thus the production of highly reactive hydrogen.

Therefore, the voltage utilized for polarization is at least:
-Overvoltage at the electrode-Contact resistance at the electrode / electrolyte interface-Resistance drop in the material, especially in the electrolyte-Should be affected by the standard thermodynamic reaction voltage at the electrode.

In this case, the present invention utilizes a proton conducting electrolyte under vapor pressure for electrolysis of water at high temperatures for the production of hydrogen and for the electroreduction of CO ₂ and / or CO at the cathode. Propose.

The method thus comprises the following steps:
The introduction of protonated species into the membrane under the influence of the pressure of the gas stream containing the vapor,
- a reducing process gas in the electrolytic and cathode chamber of the steam (CO ₂ and / or CO).

  Due to the gas stream containing the steam, the protonation of the membrane is facilitated by pressurized steam, which is advantageously used to obtain the desired conductivity at a given temperature. Such a method is described, for example, in French Patent Application No. 07/55418, filed on June 1, 2007.

  As shown in this application, Applicants have observed that an increase in the relative partial pressure of the vapor leads to an increase in the ionic conductivity of the membrane.

  This correlation between the increase in relative partial pressure and the increase in conductivity can allow suitable materials to function at lower temperatures. In other words, the decrease in conductivity promoted by acting at a lower temperature is compensated by an increase in the relative partial pressure of the vapor.

According to the present invention, “highly reactive” hydrogen is produced at the cathode, generating hydrogen (H ₂ ) when no reducing compound is present, or C _x H _y when CO ₂ and / or CO is present. O _z type compounds (x ≧ 1, y is 0 to 2x + 2 and z is 0 to 2x) can be generated.

のドープトペロブスカイト材料など、水の導入を促進する材料から製造される。陽極および陰極のために利用された材料は、優先的にセラミック−金属材料（電解質のために利用された金属とペロブスカイト材料との混合物）である。膜は好ましくは、Ｏ₂およびＨ₂ガスに対して不透過性である。 Proton conducting membrane has the general formula

Manufactured from materials that facilitate the introduction of water, such as doped perovskite materials. The material utilized for the anode and cathode is preferentially a ceramic-metal material (a mixture of metal and perovskite material utilized for the electrolyte). The membrane is preferably impermeable to O ₂ and H ₂ gases.

Generally, the film is composed of deficient perovskite, non-stoichiometric perovskite and / or doped perovskite of the general formula ABO ₃ , fluorite, pyrochlore A ₂ B ₂ X ₇ , apatite Me ₁₀ (XO ₄ ) ₆ Y ₂ , oxy Grafted with apatite Me ₁₀ (XO ₄ ) ₆ O ₂ structure, hydroxylapatite Me ₁₀ (XO ₄ ) ₆ (OH) ₂ structure, silicate structure, aluminosilicate (phyllosilicate or zeolite), oxysilicate grafted silicate or phosphate May be the type of silicate made.

  More generally, the electrolytes are advantageously high temperature or intermediate either by their tunnel or sheet structure and / or by the presence of vacancies that can introduce protonated species with a small molecular size. Any of the compounds utilized as temperature proton conductors may be used.

The present invention is capable of many variations. In particular, materials that allow the introduction of protonated species may be impermeable to O ₂ and H ₂ gases and / or protons at a densification level greater than 88%, preferably at least 94%. The introduction of chemical species can be made possible.

  In fact, a good compromise between the highest densification level possible (especially with respect to electrolyte mechanical strength and gas permeation) and the ability of the material to introduce protonated species is found. It must be. Increasing the partial pressure of the vapor that introduces the protonated species into the membrane compensates for the increased level of densification.

  The material that enables the injection of water by modification is an oxygen atom deficient oxide such as an oxygen deficient perovskite that acts as a proton conductor. Furthermore, oxygen atom deficient oxides may exhibit stoichiometric spacing and / or may be doped.

によって２つのヒドロキシル基（またはオキシド部位のＨ＋プロトン）に解離する。 Indeed, nonstoichiometry and / or doping can produce oxygen atomic vacancies. Thus, in the case of proton conduction, protonated species are introduced into the structure by exposing perovskites that exhibit stoichiometric spacing and / or doped (and thus oxygen-deficient) perovskites to vapor under pressure. Let Water molecules fill oxygen vacancies and react:

Dissociates into two hydroxyl groups (or H + protons at the oxide site).

  It is pointed out that materials other than non-stoichiometric and / or doped perovskites may be utilized as materials that promote the introduction of water and promote its dissociation in the form of protonated species and / or hydroxides.

For example, fluorite structure, pyrochlore A ₂ B ₂ X ₇ structure, apatite Me ₁₀ (XO ₄ ) ₆ Y ₂ structure, oxyapatite Me ₁₀ (XO ₄ ) ₆ O ₂ structure, hydroxylapatite Me ₁₀ (XO ₄ ) ₆ ( OH) ₂ structures, crystal structures such as silicates, aluminosilicates, phyllosilicates or phosphates.

  These structures may possibly be grafted by oxyacid groups. In fact, all structures with a high affinity for water and / or protons can be expected.

Claims (17)

Electrolyze steam injected under pressure into an anode chamber (32) of an electrolytic cell (30) comprising a proton conducting membrane (31) made from a material capable of introducing protonated species into the membrane under steam. A process for the oxidation of water injected in the form of steam is carried out in the anode (32) and migrates into the membrane in this same membrane, carbon dioxide CO ₂ and / or monoxide A method of generating protonated species that is reduced at the surface of the cathode (33) in the form of reactive hydrogen atoms capable of reducing carbon CO includes the following steps:
Introducing CO ₂ and / or CO under pressure into the cathode chamber (33) of the electrolytic cell (30);
The generated reactive hydrogen atoms reduce the CO ₂ and / or CO introduced into the cathode chamber (33) so that the CO ₂ and / or CO is C _x H _y O _z Forming a compound of the type (x ≧ 1, y is 0 to 2x + 2, and z is 0 to 2x). 2. The electrolysis method according to claim 1, comprising a step of controlling properties of the C _x H _y O _z type compound formed by a voltage / current pair applied to the cathode. Using a proton conducting membrane (31) that is impermeable to diffusion of oxygen O ₂ and H ₂ and allows introduction of protonated species into the membrane (31) under vapor pressure. The electrolysis method according to claim 1, wherein the electrolysis method is characterized. Deficient perovskite, non-stoichiometric perovskite and / or doped perovskite of general formula ABO ₃ , fluorite, pyrochlore A ₂ B ₂ X ₇ , apatite Me ₁₀ (XO ₄ ) ₆ Y ₂ , oxyapatite Me ₁₀ (XO ₄ ) ₆ Proton conducting membranes of O ₂ structure, hydroxylapatite Me ₁₀ (XO ₄ ) ₆ (OH) ₂ structure, silicate structure, aluminosilicate, phyllosilicate, zeolite, silicate grafted with oxygen acid or silicate grafted with phosphate The electrolysis method according to claim 3, comprising a step of using (31).   Using the electrolyte supported by the cathode (33) or by the anode (32) as the proton conducting membrane (31) and including reducing the thickness thereof to increase its mechanical strength. The electrolysis method according to claim 4, characterized in that   6. The method according to claim 1, further comprising a step of using a relative partial pressure of the vapor that is 1 bar or more and less than or equal to the breaking pressure of the joined body, the latter being at least 100 bar or more. Electrolysis method.   7. Electrolysis method according to any one of the preceding claims, characterized in that the relative partial pressure of the steam is advantageously greater than or equal to 50 bar. 8. The method according to claim 1, wherein the relative pressure of CO ₂ and / or CO is 1 bar or more and less than or equal to the breaking pressure of the joined body, and the latter is at least 100 bar or more. The electrolysis method described in 1.   Electrolysis method according to any one of claims 1 to 8, characterized in that the electrolysis temperature is between 200 ° C and 800 ° C, preferably between 350 ° C and 650 ° C.   10. The porous structure (32, 33) according to any one of claims 1 to 9, characterized in that it is either a mixed ceramic-metal material or "ceramic" electrode with electronic and ionic conduction. The electrolysis method described in 1.   For the cathode (33), the ceramic-metal material is compatible with the electrolyte in which the ceramic forms the membrane (31), and the properties of the dispersed metal are preferably cobalt, copper, molybdenum, 11. A ceramic-metal material which is a metal and / or metal alloy including metals such as silver, iron, zinc, noble metals (gold, platinum, palladium) and / or transition elements. Electrolysis method.   The ceramic-metal material, for the anode (32), is compatible with the electrolyte from which the ceramic forms the membrane (31) and the nature of the dispersed metal is preferably a metal alloy or passivated 12. Electrolysis method according to claim 10 or 11, characterized in that it is a ceramic-metal material which is a possible metal. Steam electrolyzer for electrolyzing steam introduced under pressure into an anode chamber of an electrolytic cell comprising a proton conducting membrane made from a material that allows injection of protonated species into the membrane under steam after oxidation (30)
An electrolyte (31) in the form of an ion-conducting membrane made from said material that allows the injection of protonated species into the membrane under the influence of water pressure;
-An anode (32);
A cathode (33);
A steam electrolyzer comprising a generator (34) capable of generating a current to apply a potential difference between the anode (32) and the cathode (33);
-Means (35) for introduction of vapor into the electrolyte (31) under pressure via the anode (32);
Means (36) for injecting CO ₂ and / or CO under pressure into the cathode chamber of the electrolytic cell;
A steam electrolysis device, characterized in that it comprises means for reducing the CO ₂ and / or CO introduced into the cathode chamber by the method according to one of the preceding embodiments. Characterized in that the material that allows the injection of protonated species is impermeable to O ₂ and H ₂ gas, steam electrolysis apparatus according to claim 13.   Steam electrolysis according to any one of claims 13 or 14, characterized in that the material enabling the injection of protonated species has a densification level of more than 88%, preferably at least 94%. apparatus.   16. The material according to any one of claims 13 to 15, characterized in that the material enabling the implantation of protonated species is an oxygen atom deficient oxide such as an oxygen deficient perovskite acting as a proton conductor. Steam electrolyzer.   The steam electrolysis apparatus according to claim 16, wherein the oxygen atom deficient oxide presents a stoichiometric interval and / or is doped.

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