Process and catalyst for hydrogen production by plasma-catalyzed decomposition of ammonia - Patent Application 20070123333

Abstract

The present invention relates to a process for converting a gas comprising NH3 in the presence of a low temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD), and a catalyst comprising a support comprising alumina, at least one promoter comprising nickel and iron. The present invention also relates to such a catalyst and its use for producing high added value molecules such as hydrogen (H2).

Description

[Technical field]

[0001] The present invention relates to chemical transformations, particularly dihydrogen (H 2 ) and dinitrogen (N 2 ) to produce ammonia (NH 3 In particular, the invention relates to the conversion of H in the presence of a catalyst and a low-temperature plasma, for example produced by a dielectric barrier discharge, the so-called DBD, which allows chemical conversion via plasma catalysis. 2 and N 2 to NH 3 The present invention also relates to said catalyst, a process for preparing said catalyst and the use of the catalyst for converting ammonia to produce high added value molecules such as hydrogen. [Background technology]

[0002] Due to the enormous increase in energy demand and the impact of fossil fuels on the environment, the search for new energy resources is receiving increased attention.

[0003] Hydrogen fuel is recognized as an ideal candidate to solve the energy and environmental crisis. Moreover, its use in fuel cell vehicles reduces the amount of CO2 emitted into the environment from traditional fossil fuels. x and NO x Hydrogen is particularly promising for controlling emissions. Hydrogen has a higher energy density (142 MJ / kg) than other fuels. In addition, the molecule is readily available with water and gaseous hydrocarbon fuels. Many studies have investigated hydrogen production methods such as steam reforming and water fractionation (Non-Patent Document 1).

[0004] Ammonia (NH 3 ) gas is a promising candidate for hydrogen transportation and storage. In addition, 150 Mt of NH 3 is produced annually and used worldwide. Due to its storage properties, NH 3is more beneficial than other energy vectors for hydrogen, whereas NH 3 has a higher gravimetric density than other fuels, while NH 3 The cost of energy stored per volume of ammonia is three times lower than for hydrogen. In particular, ammonia decomposition is used in at least two different fields related to energy science and environmental science. This is especially true for CO x It may also be used to remove ammonia from reformate in internal gasification combined-cycle (IGCC) power plants, which may be a future step in reducing CO 2 It could be widely deployed as a means of removal.

[0005] In recent years, N.H. 3 Decomposition of CO for fuel cells x Does not contain H 2 Conventional heterogeneous catalysis according to formula 1 has attracted much attention because of its potential use in the production of NH 3 This has been the main method for decomposing ethylenediaminetetraacetate (Non-Patent Documents 1, 2, 3).

number

[0006] NH 3Considering the high chemical stability of ammonia, conventional thermal catalytic processes require high gas pressure and large amounts of energy (thermal energy), especially temperatures in the range of 500°C to 800°C, to promote catalyst activation, shift the thermodynamic equilibrium, and ensure acceptable yields. High temperature catalytic reactions not only result in high energy consumption, but also potential catalyst deactivation due to sintering of metal active sites and formation of coke on the catalyst surface. Generally, thermal processes are catalyzed by noble metals such as Ir, Pd, Pt, Rh, and Ru for stable operation. Ruthenium (Ru), a noble metal, has the best catalytic activity for ammonia decomposition, but its cost and scarcity limit its large-scale commercial use. Unfortunately, nitrogen atoms (N) adsorbed on the surface of low-cost metal catalysts are easily absorbed by the catalysts unless the reaction is carried out at high temperatures (approximately 500°C to 800°C). ads The very slow recombinant desorption of α-ammoniophosphate inhibits the entire ammonia decomposition process (Non-Patent Documents 1, 2, 3).

[0007] As a result, the search for new processes that can operate at low temperatures and catalysts that are stable as a function of temperature is of great importance.

[0008] Various research efforts are being carried out to develop techniques for chemical synthesis by low-temperature plasma, which make it possible to overcome the temperature problems mentioned above. Among these techniques, especially the dielectric barrier discharge (DBD) in combination with the presence of heterogeneous catalysts (plasma catalysts) has been described (Non-Patent Documents 4, 5).

[0009] Different catalyst systems, plasma types, experimental parameters and reactors have been tested in the prior art to improve the conversion of ammonia. However, the efficiency of these systems remains low. Moreover, the activity, stability and cost of the catalysts described have proven unsuitable for industrial applications (6, 7). Summary of the Invention [Problem to be solved by the invention]

[0010] In particular, the object of the present invention is to provide a method for the production of ammonia (NH) in the presence of a catalyst that has high catalytic and energy yields and is adapted for large-scale application. 3 The objective of the present invention is to provide a process for the chemical conversion of hydrogen (H) into hydrogen (H) while avoiding the need for the use of precious metals. 2 )

[0011] Non-Patent Documents 6, 7, 8, 9, and Patent Documents 1, 2, and 3 all describe plasma-catalyzed conversion of ammonia (NH) in the presence of low-temperature plasma and a catalyst comprising an alumina-based support, nickel, and at least one promoter comprising iron (Fe). 3 ) is not explained. [Means for solving the problem]

[0012] A first object of the present invention is to provide a method for the synthesis of a compound according to the following reaction: 3 →3 / 2 H 2 +1 / 2N 2 Ammonia (NH 3 ) containing gas or mixture of gases, such as dihydrogen (H 2 ) and dinitrogen (N 2 ), the process being carried out in the presence of low temperature plasma and a catalyst comprising a support comprising alumina, at least one promoter comprising nickel (Ni) and iron (Fe).

[0013] A second object of the present invention is a catalyst, more specifically a so-called catalytic system, which is a catalyst for the reaction of ammonia (NH 3 ) containing gas or mixture of gases, such as dihydrogen (H 2 ) and dinitrogen (N 2 ), characterized in that the conversion is carried out in the presence of a low-temperature plasma and the catalyst comprises a support comprising alumina, at least one promoter comprising nickel and iron (Fe). For example, a catalytic system that can be activated with DBD plasma allows the production of NH under atmospheric pressure conditions with high yields in a thermal process (high temperature and pressure) as opposed to the work described in the prior art. 3 From H 2It is therefore possible to overcome all of the deficiencies of the prior art by synthesizing

[0014] According to a preferred embodiment, the catalyst comprises: a support comprising alumina, -nickel, - Iron (Fe)-containing promoters, -optionally at least one second accelerator: promoters of the transition metal type, more particularly comprising cobalt (Co), manganese (Mn), copper (Cu) or silver (Ag); - promoters of the lanthanide type, more particularly containing lanthanum (La), cerium (Ce) or gadolinium (Gd), - promoters containing alkaline earth metals, more particularly barium (Ba), and / or promoters of the alkali metal type, more particularly containing potassium (K); Includes.

[0015] A third object of the present invention relates to a process for preparing such a catalyst.

[0016] The fourth object of the present invention is to provide ammonia (NH 3 In accordance with the present invention, the use of the catalyst according to the invention for the conversion of a gas or mixture of gases containing fluorine, which conversion is carried out in the presence of a low-temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD). Effect of the Invention

[0017] The present invention overcomes all the deficiencies of the conventional thermal catalytic process as described in the prior art, thereby making it possible to obtain high catalytic and energy efficiency, and therefore large scale application. [Brief description of the drawings]

[0018] Other characteristics, objects and advantages of the invention will become apparent from the following description, which is given by way of example only and is non-limiting, and which may be read in conjunction with the accompanying drawings, in which:

[0019] [Figure 1] GC chromatogram of inlet gas before reaction by associating catalytic system 5Ni10FeAl with DBD plasma catalytic reactor. Figure 1 shows the GC chromatogram of inlet gas (containing 100% NH3) in DBD reactor combined with catalyst 5Ni10FeAl. [Diagram 2] GC chromatogram of outlet ammonia gas after reaction by associating catalytic system 5Ni10FeAl with DBD plasma catalytic reactor. Figure 2 shows the GC chromatogram of ammonia gas remaining after conversion of NH3 in DBD reactor combined with catalyst 5Ni10FeAl.

[0020] Table 1 shows the catalytic activity (i.e. conversion, selectivity) obtained for some catalysts according to the invention and comparative catalysts tested in DBD plasma. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] definition

[0022] In the context of the present invention: - expressions such as "from" (e.g. a range of values) are to be understood as including boundaries (e.g. the limits of this range of values); - any description of one embodiment is applicable and interchangeable with all other embodiments of the invention; - the term "and / or" is to be understood as meaning "and" and "or", e.g. "A and / or B" is to be understood as meaning either A and B, or A alone, or B alone; the expression "N, M and / or P" is to be understood as meaning "N and / or M and / or P", - the expression "N, M and P" is to be understood as meaning "N and M and P", - When an element or component is included in and / or selected from a list of elements or components, it is to be understood that this individual element or component may be selected and combined with other individual elements, or selected to form a subset of two or more of the exclusively listed elements or components, and further, any element or component recited in the list of elements or components may be excluded from that list.

[0023] In the present invention, the term "DBD - Dielectric Barrier Discharge" describes a discharge that occurs between two conductive elements that are separated by one or more dielectric elements.

[0024] In the present invention, the term "dielectric" describes an electrically insulating material that provides electrical insulation between the high voltage network associated with the electrodes and the electrically and thermally conductive tube connected to ground through the reactor. This type of electrically insulating material is also used inside a Dielectric Barrier Discharge (DBD) cell to generate a DBD plasma by facilitating charge accumulation on the surface of the material.

[0025] The terms "catalyst" and "catalyst system" are used interchangeably and refer to a material that promotes a chemical reaction of a reactive species (eg, a reagent fluid) as used herein.

[0026] The term "plasma catalysis" as used herein refers to the process of conducting a plasma discharge in combination with a catalyst.

[0027] The term "hydrogen" refers to dihydrogen (H 2 ) should be understood to mean

[0028] The term "support" or "catalyst support" refers in the present invention to a solid material or mixture of solid materials, which may be characterized in particular by its specific surface area on which the promoter is deposited.

[0029] The term "promoter" or "catalyst promoter", as used herein, refers to a solid material or mixture of solid materials added to the surface of a support material, generally in small amounts, that is intended to enhance the efficiency and performance of the catalyst.

[0030] Of course, the present invention has been described above by way of example only, and of course, those skilled in the art should understand that different variants of the invention can be made therefrom without departing from the scope of the invention.

[0031] Detailed Description of the Invention

[0032] NH 3 A process for converting a gas comprising:

[0033] A first object of the present invention is to provide a method for the synthesis of a compound according to the following reaction: 3 →3 / 2H 2 +1 / 2N 2 Ammonia (NH 3 ) containing gas or mixture of gases, such as dihydrogen (H 2 ) and dinitrogen (N 2 ), the process comprising low temperature plasma, a support comprising alumina, - Nickel, and - at least one promoter containing iron (Fe) The reaction is carried out in the presence of a catalyst comprising

[0034] The gases considered herein are NH 3 and may further include other species. Thus, this is NH 3 This method is aimed in particular at producing molecules of high added value in gas form. Indeed, the process of the invention can be used to convert dihydrogen (H 2 ), dinitrogen (N 2) or a mixture thereof in gas form. The product obtained from the process of the invention may also be in another form, for example partially liquid or anhydrous. In this case, the product may consist of hydrazine, ammonium nitrate and / or ammonia.

[0035] According to the present invention, NH 3 The process for converting a gas containing NH is therefore carried out in the presence of a catalyst and a low-temperature plasma, preferably generated by a dielectric barrier discharge (DBD). During the process of the invention, the catalyst is activated by the low-temperature plasma. The synergistic effect of the plasma catalyst in this process is the activation of NH 3 High value-added gas H 2 The catalyst used in the context of this conversion, comprising a support comprising alumina, at least one promoter comprising nickel and iron (Fe), in combination with a low-temperature plasma, is described in more detail below. The process of the invention is therefore carried out in the presence of a low-temperature plasma-activated catalyst. It is noted that all the features described in connection with the catalyst are applicable to the conversion process of the invention.

[0036] According to one embodiment, the selected catalyst is placed between the electrodes of the DBD reactor, allowing the gas species to circulate and is activated by a high voltage discharge (in the kV range) for a period ranging from nanoseconds to microseconds. This polarization leads to the formation of a plasma and its activation and the production of hydrocarbons, combined with adsorption, desorption and catalyst / gas interactions. The electrical energy supplied to the fixed bed in sinusoidal or pulsed high voltage form generates multiple currents on the HV (high voltage) carrier during positive and negative polarization. These streamers, from hundreds of picoseconds to tens of nanoseconds, are responsible for the negative or positive polarization of the catalytic sites.

[0037] Before the conversion, in particular before the hydrogenation step, the catalytic system according to the invention is preferably heated with H as discharge gas, if its components are in oxidized form. 2It is advantageously reduced in situ under low temperature plasma, preferably DBD plasma, at 1000 .mu.m or less.

[0038] The catalyst system according to the invention is characterized in that the catalyst system (more particularly between the particles of the catalyst system) or in their vicinity (upstream or downstream of the catalyst system in the gas stream) typically undergoes changes over time. 3 The reactor is activated by generating a strong electric field between 1010V / m and 1010V / m. This strong electric field allows the ionization of some gases and the excitation of atoms and molecules present in the gas phase. The reactor walls are made of metallic materials, alternatively, when DBD plasma is used, the reactor walls are made of dielectric materials such as quartz, alumina or ceramics. Advantageously, the reactor may be cylindrical. In addition to generating a low-temperature plasma state, the generated strong electric field is responsible for the negative or positive polarization of the catalytic sites. This polarization induces adsorption and desorption reactions, including reactions at low temperatures (for example, temperatures below 400°C or below 350°C). According to conventional methods without polarization, the operating temperatures are higher, typically in the range of 500°C to 800°C.

[0039] In particular, the reactor contains the gas to be converted, i.e. NH 3 and an outlet for discharging the formed product, which is also in gas form.

[0040] In a variant of the invention, the catalyst system of the invention is activated by DBD plasma by supplying less power than the catalyst system (i.e. the catalyst system present in the reactor, so-called catalyst bed), between 20 and 35 W / g.

[0041] Advantageously, the conversion reaction is, for example, 1.10 4 Pa~3.10 5 Pressure between atmospheric pressure (10 Pa) 5The conversion reaction may be carried out under pseudoadiabatic conditions, i.e. without insulation and without external heating, or under adiabatic conditions, i.e. insulated and without external heating, or under isothermal conditions, i.e. with adiabatic and / or external heating. The DBD plasma is generated by application of a voltage between two electrodes of 1-25 kV, preferably 2-20 kV, in particular at a frequency of 1 kHz-100 kHz. In particular, the gas hourly space velocity (GHSV) is greater than 1,000 h -1 ~150,000h -1 Preferably, this is for 100,000 hours. -1 is less than.

[0042] Optionally, a cooling system is present between the vessel intended to receive the products produced by the conversion reaction and the outlet of the reactor for condensing and removing liquids that may form during the conversion reaction.

[0043] Catalyst according to the invention

[0044] A second object of the present invention relates to a catalyst, which is ammonia (NH 3 ) containing gas or mixture of gases, such as dihydrogen (H 2 ) and dinitrogen (N 2 ), characterized in that the conversion is carried out in the presence of a low-temperature plasma and the catalyst comprises an alumina-based support, at least one promoter comprising nickel and iron (Fe). For example, a catalytic system that can be activated by DBD plasma allows the conversion of NH under atmospheric pressure conditions with high yields in a thermal process (high temperature and pressure) with respect to the work described in the prior art. 3 From H 2 It is therefore possible to overcome all of the deficiencies of the prior art by synthesizing

[0045] Preferably, the catalyst of the present invention does not contain any precious metals such as ruthenium (Ru), iridium (Ir), palladium (Pd), platinum (Pt) or rhodium (Rh).

[0046] As demonstrated in the following examples, the use of the catalyst according to the invention in combination with low temperature plasma, preferably plasma generated by dielectric barrier discharge (DBD), improves the catalytic performance of the reaction, i.e. NH 3 and the desired product (H 2 ) while improving selectivity to hydrogen (H 2 This will make it possible to produce high-added-value molecules such as

[0047] Thus, the present invention generally comprises: a support comprising alumina, - Nickel, and at least one promoter comprising iron (Fe); The present invention relates to a catalyst comprising:

[0048] According to one embodiment, the present invention relates to a low-temperature plasma activated catalyst.

[0049] In the context of the present invention, the terms "catalyst system" and "catalyst" are interchangeable. According to one embodiment of the present invention, the catalyst system is a so-called monometallic / bimetallic catalyst system. It should be noted that the concepts monometallic and bimetallic relate in particular to the species present in the catalyst, without taking into account the support and nickel used. For example, if the catalyst is doped with two promoters, we speak of a "bimetallic catalyst", and if the catalyst is doped with three promoters, we speak of a "trimetallic catalyst".

[0050] The support used in the context of the present invention is based on alumina. In particular, it is a support that is compatible with the reagents, more particularly NH 3 It is selected for its thermal stability and its specific surface area, for its ability to adsorb NH. It is also selected for its dielectric properties, which affect the properties of the plasma and change the DBD discharge behavior, electric field and electron density of the plasma due to dielectric constant and polarization effects that give rise to local electric fields. 3To obtain higher catalytic results in terms of conversion of 2 It has been found that the use of a support comprising alumina is particularly beneficial when compared to a support comprising alumina.

[0051] The support can affect the physicochemical properties (basicity, acidity, reducibility, oxygen mobility, etc. due to the presence of intrinsic defects on its surface), textural properties (pore volume, pore size, specific surface area, etc.) and electrical properties (dielectric constant, electrical conductivity, etc.) and thus modulate the catalytic performance of the system.

[0052] According to the invention, the support of the catalyst system comprises alumina, in particular the support may consist of alumina. According to one embodiment, the support is, for example, Al 2 O 3 Thus, the support of the catalyst system may further comprise other components, for example mixed oxides and / or cerium.

[0053] In the context of the present invention, alumina is any specific surface area (BET surface area m 2 For example, the specific surface area of ​​alumina may be at least 20 m 2 / g, especially 50 to 1,000m 2 For example, the specific surface area of ​​alumina may vary from 200 m 2 / g or 260m 2 According to one embodiment of the present invention, the catalyst has a molecular weight of 50 to 1,000 m 2 / g, 100-800m 2 / g, 150-300m 2 / g or 180~250m 2 The support includes an alumina-containing support having a specific surface area that varies in .mu.m / g.

[0054] The preparation of the support for the catalyst system is described in detail below. The support used in the context of the present invention may also be a commercially available support.

[0055] The catalyst of the invention also comprises nickel. The nickel of the catalyst according to the invention may be in any of its oxidation states, in particular in metallic form (under its oxidation state 0) or in its oxidation state II, which is in the oxide form (for example in the form of nickel(II) oxide (NiO)). Advantageously, the mass content of nickel in the catalytic system may vary between 0.1% and 50% by weight, for example between 0.5% and 40% by weight, or between 1% and 30% by weight, relative to the weight of the support, which is less than 20% or less than 15%. By "weight of the support" is to be understood "weight of the support including alumina", including when the support comprises elements other than alumina. In a particularly advantageous manner, the catalytic system comprises 5% ± 1% by weight of nickel relative to the weight of the support.

[0056] By convention, a catalyst containing 5% nickel and 10% iron by weight, based on the weight of the support containing alumina, is designated as "5Ni10FeAl", "5Ni10Fe-Al" or "5Ni10Fe / Al".

[0057] The catalyst of the invention comprises at least one promoter, i.e. one or more promoters, which act as dopants and influence the physicochemical, textural and conductive properties of the catalyst. Advantageously, the promoter according to the invention is a catalyst selected from the group consisting of the reagent NH 3 It is possible to improve the electrical conductivity of the resulting catalyst with suitable surface physicochemical properties that support the immobilization of NH 3 From NH 2 It is possible that the catalyst has suitable dielectric properties which logically result in the production of a radical, NH radical, followed by its desorption from the catalyst surface, thereby promoting the formation of hydrogen.

[0058] The catalyst of the present invention comprises at least one promoter comprising iron (Fe). The iron may be in any oxidation state, in particular in metallic or oxidic form. For example, the iron promoter may be in the form of FeO: iron(II) oxide or ferrous oxide, or in the form of iron(III) oxide, Fe 2 O 3 or in the form of ferric oxide, or NiO and Al 2 O3 An example of a representative catalyst of this embodiment is the catalyst 5Ni10Fe-Al, ie, a catalyst comprising a support comprising alumina, a promoter comprising nickel and iron.

[0059] The catalyst of the present invention may also comprise at least one second promoter. In particular, this second promoter may comprise a chemical element selected from the group consisting of transition metals, alkali metals, alkaline earths, lanthanoids and mixtures thereof. In the context of the present invention, the promoter is in any of its oxidation states, in particular in metallic or oxidic form. Thus, according to one embodiment of the present invention, the catalyst comprises at least two promoters, i.e. two or more promoters (for example, three or four promoters).

[0060] In the context of the present invention, the transition metal may in particular be selected from the group consisting of copper, cobalt, silver, iron, molybdenum, vanadium, manganese, chromium, yttrium, titanium and tantalum. When the second promoter comprises a chemical element which is a transition metal, the latter is preferably cobalt (Co), copper (Cu), silver (Ag) and / or manganese (Mn).

[0061] In the context of the present invention, the alkali metal may in particular be selected from the group consisting of lithium, sodium, potassium, rubidium, cesium and furan. When the second promoter comprises a chemical element which is an alkali metal, the latter is preferably potassium (K) or cesium (Cs), even more preferably potassium (K).

[0062] In the context of the present invention, the alkaline earth metal may in particular be selected from the group consisting of barium, calcium and magnesium. When the second promoter comprises a chemical element which is an alkaline earth element, the latter is preferably barium (Ba).

[0063] In the context of the present invention, the lanthanides may in particular be selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. In case the second promoter comprises a chemical element which is a lanthanide, the latter is preferably cerium (Ce), gadolinium (Gd) and / or lanthanum (La), and even more preferably cerium (Ce).

[0064] According to one embodiment of the present invention, the catalyst comprises at least one second promoter comprising cobalt (Co), manganese (Mn), copper (Cu) and / or silver (Ag).

[0065] According to one embodiment of the present invention, the catalyst comprises at least one second promoter comprising lanthanum (Ia), cerium (Ce) and / or gadolinium (Gd).

[0066] According to one embodiment of the present invention, the catalyst comprises at least one second promoter comprising barium (Ba).

[0067] According to one embodiment of the present invention, the catalyst comprises at least one second promoter comprising potassium (K).

[0068] According to a preferred embodiment, the catalyst of the present invention comprises at least one second promoter comprising cobalt (Co). An example of a representative catalyst of this embodiment is the catalyst 5Ni10Fe1Co-Al, i.e. a catalyst comprising a support comprising two separate promoters, a promoter comprising Fe and a promoter comprising Co.

[0069] The amount of nickel and / or promoter may be adjusted according to the nature of the promoter used and / or the type of conversion reaction being carried out.

[0070] According to one embodiment of the invention, the mass content of promoter in the catalyst system varies between 0.1% and 40% by weight, for example between 0.2% and 30% by weight, in particular between 0.3% and 20% by weight, preferably between 0.5% and 15% by weight, in particular between 1% and 12% by weight, even more preferably between 2% and 10% by weight, relative to the weight of the support.

[0071] The promoters used to prepare the catalysts of the invention are in any oxidation state, in particular in metallic or oxidic form. They may therefore contain other chemical elements, which are not taken into account in the calculation of the claimed mass contents. For example, for the catalyst 5Ni10Fe1Co-Al, 1 g of support containing nickel is used, followed by 0.049 g of promoter Co(NO 3 ) 2 .6H 2 0 (molar mass: 291.04 g / mol) is used. This corresponds to 0.01 g Co (molar mass: 58.93 g / mol) or 1% by weight of cobalt relative to the weight of the support. For this catalyst, the mass content of promoter is 11% by weight relative to the weight of the support, i.e. 10% iron (or "iron promoter") and 1% cobalt (or "cobalt promoter").

[0072] According to one embodiment of the invention, the mass content of Fe in the catalyst system varies between 0.1% and 40% by weight, for example between 0.2% and 30% by weight, in particular between 0.3% and 25% by weight, preferably between 0.5% and 20% by weight, in particular between 1% and 15% by weight, even more preferably between 2% and 10% by weight, relative to the weight of the support.

[0073] According to one embodiment of the present invention, the mass content of the other promoter (second promoter) in the catalyst system varies between 0.1% and 40% by weight, for example between 0.2% and 30% by weight, in particular between 0.3% and 20% by weight, preferably between 0.5% and 15% by weight, in particular between 1% and 12% by weight, and even more preferably between 2% and 10% by weight, relative to the weight of the support. For example, in addition to the promoter containing Fe, the catalyst according to the present invention comprises between 0.5% and 20% by weight of one or more other promoters (in % by weight, relative to the weight of the support) selected from the group consisting of cobalt (Co), manganese (Mn), copper (Cu), silver (Ag), lanthanum (La), cerium (Ce), gadolinium (Gd), barium (Ba) and potassium (K). According to another embodiment, in addition to the promoter containing Fe, the catalyst according to the present invention comprises between 0.1% and 4% by weight of cobalt (Co) (in % by weight, relative to the weight of the support).

[0074] According to a particular embodiment of the invention, the catalyst is doped with two promoters, one of which contains iron (Fe) and the other of which contains cobalt (Co). This is called a bimetallic catalyst. According to this embodiment, the mass content of iron in the catalyst may preferably vary between 6% and 14%, between 7% and 13% or between 6% and 12%. For example, the mass content of iron in the catalyst is 10% by weight ±0.5% by weight relative to the weight of the support. Also according to this particular embodiment, the mass content of cobalt in the catalyst may preferably vary between 0.1% and 4%, between 0.2% and 3% or between 0.5% and 2%. For example, the mass content of cobalt in the catalyst is 1% by weight ±0.5% by weight relative to the weight of the support. An example of a representative catalyst of this embodiment is the catalyst 5Ni10Fe1Co-Al, i.e. a catalyst comprising a support comprising alumina, 5% by weight of nickel relative to the weight of the alumina, and two separate promoters, 10% by weight of iron and 1% by weight of cobalt.

[0075] The catalyst may be in different forms, for example in bead, monolith, powder or granular form. In the case of a powder, the particles forming the powder have an average diameter of, for example, 1 μm to 1 mm, for example 100 μm to 1 mm, in particular 200 μm to 800 μm, preferably about 600 μm ± 20 μm. In particular, the diameter of the particles may be adapted according to the production scale used. The catalyst may also have a geometric shape, advantageously beads with an average diameter of less than 5 cm. The average diameter of the catalyst is adjusted according to the type and dimensions of the fixed bed reactor used, in order to avoid any pressure drop.

[0076] According to one embodiment of the present invention, the support, nickel and at least one promoter form a homogeneous mixture, in particular the support modified with nickel and a promoter forms a homogeneous mixture, meaning that the nickel and the promoter are uniformly distributed throughout the entire volume of the catalyst.

[0077] According to a preferred embodiment, the catalyst of the present invention comprises: a support comprising alumina, -nickel, - Iron (Fe)-containing promoters, -optionally at least one second accelerator: promoters of the transition metal type, more particularly comprising cobalt (Co), manganese (Mn), copper (Cu) or silver (Ag); - promoters of the lanthanide type, more particularly containing lanthanum (La), cerium (Ce) or gadolinium (Gd), - promoters containing alkaline earth metals, more particularly barium (Ba), and / or promoters of the alkali metal type, more particularly containing potassium (K); Includes.

[0078] According to another preferred embodiment, the catalyst of the present invention comprises a support comprising alumina, 0.1% to 50% by weight of nickel (% by weight relative to the weight of the support), - 0.1 wt. % to 40 wt. % of promoter (wt. % relative to the weight of the support), including at least one promoter containing iron (Fe), and optionally at least one second promoter: promoters of the transition metal type, more particularly comprising cobalt (Co), manganese (Mn), copper (Cu) or silver (Ag); - promoters of the lanthanide type, more particularly containing lanthanum (La), cerium (Ce) or gadolinium (Gd), - promoters containing alkaline earth metals, more particularly barium (Ba), and / or promoters of the alkali metal type, more particularly containing potassium (K); Includes.

[0079] According to another preferred embodiment, the catalyst of the present invention comprises a support comprising alumina, 0.1% to 50% by weight of nickel (% by weight relative to the weight of the support), - 0.1 wt. % to 40 wt. % of a promoter (wt. % relative to the weight of the support), including a promoter comprising iron (Fe), and at least one second promoter selected from among cobalt (Co), manganese (Mn), copper (Cu), silver (Ag), lanthanum (La), cerium (Ce), gadolinium (Gd), barium (Ba) and potassium (K), Includes.

[0080] According to another preferred embodiment, the catalyst of the present invention comprises a support comprising alumina, 0.1% to 50% by weight of nickel (% by weight relative to the weight of the support), - 0.5 wt.% to 20 wt.% of an iron (Fe) promoter (% by weight relative to the weight of the support), and - 0.5% to 20% by weight of one or more promoters (% by weight relative to the weight of the support) selected from the group consisting of cobalt (Co), manganese (Mn), copper (Cu), silver (Ag), lanthanum (La), cerium (Ce), gadolinium (Gd), barium (Ba) and potassium (K); Includes.

[0081] According to another preferred embodiment, the catalyst of the present invention comprises a support comprising alumina, 0.1% to 50% by weight of nickel (% by weight relative to the weight of the support), - 0.5 wt.% to 20 wt.% of an iron (Fe) promoter (% by weight relative to the weight of the support), and - 0.1 wt.% to 4 wt.% of a cobalt (Co) promoter (% by weight relative to the weight of the support); Includes.

[0082] Catalyst System Preparation Process

[0083] The preparation of the catalyst system according to the invention may be carried out according to different processes.

[0084] In particular, the catalyst system may be prepared by a process comprising contacting a support comprising alumina with at least one of a nickel precursor and a promoter(s). This step makes it possible to form a solid comprising the support, nickel and the promoter(s). Optionally, the process comprises a step of calcining the mixture thus obtained. Before the contacting step, a step of modifying the support is optionally performed. Furthermore, after the optional calcination step, a step of reducing the calcined mixture is optionally performed.

[0085] The step of contacting the support with the nickel precursor and the promoter precursor may be carried out, for example, by impregnation, co-precipitation or sol-gel, three of which specific embodiments (so-called subvariants) are described in detail below.

[0086] The nickel precursor and the precursor of the promoter may consist of any compound or mixture of compounds containing the metal used as active metal / promoter, more particularly the salt of said metal, the oxide of said metal or a mixture thereof, preferably the salt of said metal or a mixture of said salts of said metal. The salt of said metal (meaning the non-hydrated or hydrated, polyhydrated salt) may be chosen, for example, from among the chlorides, nitrates, carbonates, acetates, acetylacetonates, tartrates and citrates of said metal and mixtures thereof, preferably the nitrates of said metal. In case the promoter is a mixture of several metals, the precursor may be a mixture of different salts and / or oxides of these metals.

[0087] The calcination step results in the oxidation of the different components of the catalytic system (support, nickel and promoter). This optional calcination step is then optionally followed by a reduction step to change the oxidation state of the nickel and promoter (with nickel and metal promoter) and possibly the oxidation state of the support. The reduction may be complete or partial, i.e. only some of the components of the catalytic system may be reduced. The reduction step may be carried out in situ in a non-thermal plasma under hydrogen.

[0088] According to a first variant of the process according to the invention, the process for preparing a catalyst system according to the invention comprises the steps of: - contacting a support comprising alumina with a nickel precursor and one or more precursors of a promoter; - optionally calcining the mixture obtained after contacting the components; - optionally reducing the calcined mixture obtained in the previous step, Includes.

[0089] According to a second variant of the process according to the invention, the process for preparing a catalytic system according to the invention comprises the steps of: - contacting a support comprising alumina with a nickel precursor and one or more precursors of a promoter; - calcining the mixture obtained after contacting the ingredients; - optionally reducing the calcined mixture obtained in the previous step, Includes.

[0090] According to a third variant of the process according to the invention, the process for preparing a catalytic system according to the invention comprises the steps of: - contacting a support comprising alumina with a nickel precursor and one or more precursors of a promoter; - calcining the mixture obtained after contacting the ingredients; - reducing the calcined mixture obtained in the previous step, Includes.

[0091] According to a fourth variant of the process according to the invention, the process for preparing a catalytic system according to the invention comprises the steps of: - modifying a support comprising alumina, and - contacting the modified support with a nickel precursor and one or more precursors of a promoter; - optionally calcining the mixture obtained after contacting the components; - optionally reducing the calcined mixture obtained in the previous step, Includes.

[0092] In particular, the step of contacting the components may be carried out by impregnation. More particularly, according to a first sub-variant, the method comprises the following steps: 1) preparing a carrier; and 2) contacting the components by impregnation; Includes.

[0093] Thus, step 1) of preparing the support comprises the following substeps: 1.1) Preparation of a suspension containing an alumina precursor or an alumina oxide precursor. According to this step 1.1), the support precursor corresponds to an alumina precursor or a mixture of several precursors. When the support is a mixture of cerium and alumina, in particular a mixed oxide, the cerium precursor suspension and the alumina precursor suspension are advantageously prepared separately and then mixed in a ratio making it possible to obtain the desired molar ratio Ce / Al in the final mixture of cerium and alumina, in particular in the mixed oxide. 1.2) Mixing the suspension obtained from step 1.1). In particular, the addition of these precursors is carried out at room temperature, for example at 20-25° C. with continuous mixing, for 30 minutes to several hours, for example 30 minutes to 3 hours. 1.3) Recovery of the solid obtained in step 1.2) by removal of excess water, in particular by evaporation or filtration of the water, followed by drying of the solid obtained. In particular, the drying step may be carried out at a temperature below 150° C., typically at a temperature of about 100° C., for a period varying, for example, from 5 hours to 48 hours. 1.4) Calcination of the solid obtained from step 1.3) to obtain the support. The product obtained from step 1.3) is calcined, for example at a temperature between 300° C. and 600° C. This calcination step may be carried out for a period varying from 3 hours or more, for example between 3 hours and 6 hours. This step results in the thermal decomposition of the nitrates to obtain the oxides.

[0094] Thus, step 2) of contacting the components comprises the following substeps: 2.1) Preparation of an aqueous suspension containing a nickel precursor and one or more precursors of promoters. During this step, an appropriate mass of each precursor was added to an appropriate volume of solvent (e.g. water). By "appropriate mass" and "appropriate volume" should be understood the appropriate amounts of precursor and solvent (especially water) to obtain the desired mass contents of nickel and promoter in the final catalyst system. 2.2) Addition of the carrier obtained from step 1) to the aqueous solution obtained from step 2.1) to obtain a suspension. 2.3) Mixing the suspension obtained from step 2.2). The addition of these precursors is carried out at room temperature, for example at 20 to 25° C. with continuous mixing, for 30 minutes to several hours, for example 30 minutes to 3 hours. 2.4) Recovery of the solid comprising the support, nickel and promoter obtained in step 2.3) by removing the excess water, in particular by evaporation or filtration of the water, followed by drying of the solid obtained. For example, the drying step may be carried out at a temperature of less than 150° C., typically at a temperature of about 100° C., for a period in the range, for example, from 7 hours to 48 hours. 2.5) Calcination of the solid obtained from step 2.4) to obtain the catalytic system. The product obtained from step 2.4) is calcined, for example at a temperature between 300° C. and 600° C. This calcination step may be carried out for a period varying from 3 hours or more, for example between 3 hours and 6 hours. This step results in the thermal decomposition of the nitrates to obtain the oxides.

[0095] This first suboption is also the so-called wet impregnation process, which consists of impregnation of the support with a nickel precursor and a precursor of the promoter.

[0096] Alternatively, the step of contacting the components may be carried out by co-precipitation. More specifically, according to a second subvariant, the process for preparing the catalyst system comprises: 1') preparing a carrier; and 2') contacting the support with a nickel precursor and a promoter, the contacting being carried out by co-precipitation; Includes.

[0097] Step 1') of preparing the support consists of preparing an aqueous solution containing a nickel precursor and a precursor of the promoter. This step is identical to step 2.1) of the wet impregnation process described above.

[0098] Thus, the step 2') of contacting the components comprises the following substeps: 2.1') ​​Addition of a carrier to the solution obtained from step 1') to obtain a suspension. This step is identical to step 2.2) of the wet impregnation process described above. 2.2') Addition of a base to the suspension obtained in step 2.1'). During this step, a base is added to the suspension obtained from step 2.1'). Advantageously, this base is a hydroxide salt, such as sodium hydroxide, potassium hydroxide, sodium or potassium carbonate, preferably sodium hydroxide. It may be used in the form of a solution, in particular an aqueous solution. The base is slowly added dropwise until the pH of the suspension (consisting of the solids in suspension, which is a solution) is equal to 8-12, preferably about 10. Step 2.2') may be carried out at a temperature between 60°C and 100°C, in particular between 70°C and 90°C, preferably equal to about 80°C. 2.3') Mixing of the suspension obtained from step 2.2'). This step has the purpose of precipitating the hydroxide of the metal used as promoter on the surface of the nickel hydroxide and the support. For example, mixing, in particular mixing by stirring, is carried out at a temperature equal to 60° C. to 100° C., preferably about 80° C. This mixing step may be carried out for a period of more than 2 hours, usually about 3 hours. 2.4') Recovery of the solid comprising the support, nickel and promoter obtained in step 2.3') and its calcination to give the catalytic system. This step is identical to step 2.5) of the wet impregnation process.

[0099] This second subvariant makes it possible to precipitate the hydroxides of the metals used as promoters on the surface of the nickel hydroxide and the support.

[0100] The step of contacting the components may be carried out by a sol-gel reaction. More specifically, according to a third subvariant, the step of contacting the support with the nickel precursor and the precursor of the promoter is carried out by a sol-gel reaction and comprises the following substeps: 1'') preparing a solution containing a nickel precursor, a precursor of the promoter (or precursors of multiple promoters) and a carrier precursor of citric acid; 2″) adjusting the pH of 1″) to, for example, 4, by adding a strong base solution, preferably NaOH; 3'') heating the solution of step 2'') at reflux; and 4'') removing excess citric acid and recovering the catalytic system; Includes.

[0101] In step 1″), the support precursor corresponds to an alumina precursor, a cerium precursor, a lanthanum precursor or a mixture of an alumina precursor, a cerium precursor and a lanthanum precursor, depending on whether the support is alumina, cerium, lanthanum or a mixture of alumina, cerium and lanthanum. When the support is a mixture of alumina, cerium and lanthanum, in particular a mixed oxide, the solutions of the alumina precursor, the cerium and lanthanum precursors are advantageously prepared separately and then mixed in a ratio that makes it possible to obtain the desired Al / Ce and Ce / La molar ratios in the final mixture of cerium and lanthanum alumina, in particular in the mixed oxide.

[0102] To prepare the desired amount of catalyst, the precursor of the support, and the nickel precursor (e.g. nickel(II) acetate tetrahydrate) and promoter are advantageously dissolved separately in citric acid, in particular with heating (e.g. at 80-120°C, in particular at about 80°C for at least 1 hour, e.g. about 2 hours).

[0103] The reflux heating step 3'') is carried out for a period sufficient to obtain a gel.

[0104] If the product resulting from step 3'') is a gel, it may be dried or solidified in an oven before carrying out a possible calcination step, in particular using liquid nitrogen, in which the product resulting from step 3'') may be solid.

[0105] The final step 4″) consists in recovering the solid obtained in step 3″), this step being identical to step 2.5) of the wet impregnation process.

[0106] The support used in the process of preparing the catalyst system may also be a commercially available support.

[0107] Use of the catalyst according to the invention

[0108] The present invention also relates to ammonia (NH 3 With regard to the use of the catalyst according to the invention for the conversion of a gas or a mixture of gases containing argon, the conversion being carried out in the presence of a low-temperature plasma.

[0109] The present invention is particularly directed to 3 The present invention relates to the use of the catalyst of the present invention in combination with a low-temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD), for converting a gas or a mixture of gases comprising:

[0110] In other words, the present invention is particularly 3 The present invention relates to the use of a catalyst according to the invention activated by a low-temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD), for converting a gas or a mixture of gases comprising:

[0111] In fact, the inventors have demonstrated that the combination of the catalyst according to the present invention with a low-temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD), can effectively reduce the amount of NH 3 and / or the production of hydrogen, e.g. dihydrogen (H 2 ) and gaseous dinitrogen (N 2 It has been recognized that this results in increased efficiency for producing

[0112] The present invention also relates to a method for producing a compound comprising the steps of: 3 Dihydrogen (H 2 ) and dinitrogen (N 2 The present invention relates to the use of the catalyst system according to the invention for the preparation of

[0113] The present invention is particularly directed to 3 Dihydrogen (H 2 ) and dinitrogen (N 2 The present invention relates to the use of the catalyst of the present invention in combination with a low-temperature plasma, preferably a plasma generated by dielectric barrier discharge (DBD), for the production of fluorinated isocyanates.

[0114] The present invention is particularly directed to 3 Dihydrogen (H 2 ) and dinitrogen (N 2 The present invention relates to the use of the catalyst of the present invention, which is activated by a low-temperature plasma, preferably a plasma generated by a dielectric barrier discharge (DBD), for the production of fluorinated isocyanates. [Prior art documents] [Non-patent literature]

[0115] [Non-Patent Document 1] Yoshitsugu Kojima, Masakuni Yamaguchi, Ammonia as a hydrogen energy carrier, International Journal of Hydrogen Energy, 2022, ISSN 0360-3199, https: / / doi.org / 10.1016 / j.ijhydene.2022.05.096 [Non-Patent Document 2] Schuth,F.and Palkovits,R.and Schlogl,R.and Su,DS,Ammonia as a possible element in an energy infrastructure:catalysts for ammonia decomposition,Energy Environ.Sci.,2012,Volume 5,p.6278-6289,http: / / dx.doi.org / 10.1039 / C2EE02865D [Non-Patent Document 3] Dejiang Zhou; Renwu Zhou; Rusen Zhou; Baowang Liu; Tianqi Zhang; Yubin Xian; Patrick J. Cullen; Xinpei Lu; Kostya(Ken) Ostrikov; Journal,(),-.https: / / doi.org / doi:10.1016 / j.cej.2021.129544

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[0116] [Patent Document 1] Chinese Patent Application No. 101147863 [Patent Document 2] European Patent Application No. 2332646 [Patent Document 3] International Publication No. 2021 / 255422 EXAMPLES

[0117] The present invention will be described in more detail with reference to the following examples, which are intended for illustrative purposes and are not intended to limit the scope of the present invention.

[0118] A. Preparation of different catalytic systems by wet impregnation

[0119] Several supports were used to prepare various catalyst systems, which are more specifically identified in Table 1 below. 1) Commercially available alumina oxide (Al200, specific surface area = 200 m 2 / g,Saint Gobain), 2) Commercially available alumina oxide (Al260, specific surface area = 260 m 2 / g,Saint Gobain), 3) Commercially available serine-zirconia mixed oxide from Sigma Aldrich (CZ) 4) Commercially available silica oxide SiO 2 (Si160, specific surface area=160m 2 / g,Saint Gobain), 5) Commercially available magnesium oxide MgO from Sigma Aldrich; 6) Mixed oxides synthesized by the inventors according to the process described above.

[0120] The different catalysts given as examples herein are prepared by wet impregnation.

[0121] The nickel catalyst system doped with a promoter (metal M) was 3 ) 2 .6H 2 O (Sigma-Aldrich) and, depending on the desired promoter, Fe(NO 3 ) 2 .9H 2 O, Co(NO 3 ) 2 .6H 2 O, Mn(NO 3 ) 2 .4H 2 O, La(NO 3 ) 2 .6H 2 O, Y(NO 3 ) 2 .6H 2 O, Gd(NO 3 ) 3 6H 2 O, Ba(NO 3 ) 2 , Ag(NO 3 ), Cs(NO 3 ), Ce(NO 3 ) 3 6H 2 O, Cu(NO 3 ) 2 .5H 2 O, NaNO 3 and KNO 3 The solutions were prepared by a process from an aqueous solution with one or more promoter precursors selected from among (all commercially available, Sigma-Aldrich).

[0122] For example, for the preparation of the catalyst 5Ni10Fe-Al (one of the catalysts according to the invention), the nickel content is 5% by weight relative to the weight of the support and the Fe promoter content is 10% by weight relative to the weight of the support.

[0123] An appropriate mass of nickel salt and an appropriate mass of promoter precursor are dissolved in water with a volume of 50 mL at room temperature and under stirring. An appropriate mass of carrier is added to the aqueous solution containing the mixture of metal salts and kept stirring for 2 hours. For example, according to the above procedure, 0.25 g of nickel nitrate (representing a nickel content of 5 wt.% relative to the weight of the carrier), 0.72 g of iron nitrate (representing an iron content of 10 wt.% relative to the weight of the carrier) and 1 g of carrier are mixed. The mixture is then placed in a rotary evaporator at 60° C. to remove excess water.

[0124] After impregnation and evaporation of water, all samples were collected and dried in an oven at 100 °C for 8 h. They were then calcined in air at 550 °C for 4 h with a temperature gradient of 10 °C / min. After calcination, the catalyst system samples were hand-ground and screened to an average particle size of 50-200 μm.

[0125] Different catalysts prepared according to the above method are listed in Table 1 below.

[0126] B. NH in the presence of different catalysts 3 Conversion of gases containing

[0127] The procedure for producing hydrogen by catalytic plasma reactor is as follows: 22,000h -1 320 mg of the catalyst to be tested, corresponding to a GHSV (space velocity) of 10 ...

[0128] A non-thermal dielectric barrier discharge (DBD) plasma was generated between two electrodes: a copper cylindrical electrode placed inside an alumina tube (diameter 3 mm) surrounded by a quartz coaxial tube (inner diameter 10 mm, thickness 1 mm) and a steel wire wrapped around the outer surface of the quartz tube acting as a ground electrode (grounded via an external capacitor of 2 nF). In this configuration, the discharge was maintained over a length of about 1 cm and in a space of 2.5 mm. Prior to catalytic testing, the synthesized catalytic system was charged in a 2000 keV gas containing H as the discharge gas. 2The mixture is reduced in situ under a non-thermal DBD plasma at 40° C. for a period of 60 minutes.

[0129] The activity and selectivity of promoted and unpromoted catalysts under DBD plasma conditions are evaluated in an experimental setup comprising a quartz tubular cylindrical reactor, a DBD plasma generator and corresponding equipment for gas supply and analysis.

[0130] In the absence of plasma, no change in the composition of the outlet gas is observed. After the plasma is ignited and stabilized, hydrogen and dinitrogen are produced at the outlet.

[0131] The following formula was used to evaluate the catalytic performance and NH 3 Conversion of H 2 and N 2 The selectivity of was calculated.

number

number

number

[0132] C. Results

[0133] Table 1 below lists and summarizes the catalysts tested. 3 Conversion and H 2 and N 2 The catalytic activity results obtained in terms of selectivity are shown. [Table 1]

[0134] Figure 1 shows the effect of combining the 5Ni10FeAl catalyst system (catalyst 12i in Table 1 above) with a DBD plasma catalytic reactor on the inflow of gas (100% NH 3 GC chromatogram of the compound (containing

[0135] Figure 2 shows the NH 3 1 shows a GC chromatogram of ammonia gas remaining after the reaction after conversion of

Claims

1. The reaction: [0010] According to this, ammonia (NH ３ A gas or mixture of gases containing dihydrogen (H ２ ) and dinitrogen (N ２ ) into a gas, which comprises a low-temperature plasma, A support comprising alumina; Nickel, and At least one promoter comprising iron (Fe) The process is carried out in the presence of a catalyst comprising:

2. The catalyst further comprises at least one second promoter: a promoter comprising a transition metal species, more particularly cobalt (Co), manganese (Mn), copper (Cu) or silver (Ag); promoters of the lanthanide type, more particularly containing lanthanum (La), cerium (Ce) or gadolinium (Gd); promoters including alkaline earth metals, more particularly barium (Ba); and / or promoters of the alkali metal type, more particularly including potassium (K); The process of claim 1 further comprising:

3. the mass content of promoter in the catalyst varies from 0.1% to 40% by weight, preferably from 0.5% to 20% by weight, relative to the weight of the support, or the mass content of iron in the catalyst varies between 0.1% and 40% by weight, preferably between 0.5% and 20% by weight, relative to the weight of the support; 3. The process according to claim 1 or 2,

4. The process according to any one of claims 1 to 3, wherein the catalyst comprises at least one second promoter comprising cobalt (Co).

5. the mass content of iron varies between 6 and 14% relative to the weight of the support, and / or The mass content of cobalt varies from 0.1% to 4% relative to the weight of the support; According to the process of any one of claims 1 to 4.

6. The process according to any one of claims 1 to 5, wherein the support is an alumina oxide.

7. 7. The process according to any one of claims 1 to 6, wherein the mass content of nickel in the catalyst varies between 0.1% and 50% by weight, preferably less than 20% by weight, relative to the weight of the support.

8. The process according to any one of claims 1 to 7, wherein the low temperature plasma is generated by dielectric barrier discharge (DBD).

9. The catalyst is A support comprising alumina; 0.1% to 50% by weight of nickel (by weight, based on the weight of the support); and 0.1 wt. % to 40 wt. % promoter (wt. % based on the weight of the support) including an iron (Fe) promoter and at least one second promoter selected from among cobalt (Co), manganese (Mn), copper (Cu), silver (Ag), lanthanum (La), cerium (Ce), gadolinium (Gd), barium (Ba) and potassium (K); The process according to any one of claims 1 to 8, further comprising:

10. The reaction: [0025] According to this, ammonia (NH ３ A gas or mixture of gases containing dihydrogen (H ２ ) and dinitrogen (N ２ ) into a catalyst, the conversion being carried out in the presence of a low temperature plasma, the catalyst comprising: A support comprising alumina; Nickel, and At least one promoter comprising iron (Fe) A catalyst comprising:

11. At least one second accelerator: a promoter comprising a transition metal species, more particularly cobalt (Co), manganese (Mn), copper (Cu) or silver (Ag); promoters of the lanthanide type, more particularly containing lanthanum (La), cerium (Ce) or gadolinium (Gd); of alkaline earth metals, more particularly barium (Ba), and / or Alkali metal species, more particularly potassium (K); The catalyst of claim 10 further comprising:

12. Catalyst according to claim 10 or 11, according to which the mass content of said promoter in said catalyst varies from 0.1% to 40% by weight, preferably from 0.5% to 20% by weight, relative to the weight of the support.

13. 0.1% to 50% by weight of nickel (% by weight relative to the weight of the support); 0.5% to 20% by weight of iron (Fe) (by weight, relative to the weight of the support); and 0.5% to 20% by weight of one or more promoters (by weight, based on the weight of the support) selected from the group consisting of cobalt (Co), manganese (Mn), copper (Cu), silver (Ag), lanthanum (La), cerium (Ce), gadolinium (Gd), barium (Ba) and potassium (K); The catalyst according to any one of claims 10 to 12, comprising:

14. the mass content of iron varies between 6 and 14% relative to the weight of the support, and / or The mass content of cobalt (Co) varies from 0.1% to 4% relative to the weight of the support; Catalyst according to any one of claims 10 to 13, optionally comprising at least one second promoter comprising cobalt (Co).

15. Ammonia (NH ３ 15. Use of the catalyst according to any one of claims 10 to 14 for converting a gas or a mixture of gases comprising 1,2-dichlorophenyl ether (COOH), wherein said conversion is carried out in the presence of a low-temperature plasma, preferably a plasma generated by dielectric barrier discharge (DBD).

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