Method of forming catalyst for electrocatalysis, catalyst for electrocatalysis, and device

Abstract

The invention relates to a method (1, 10) for forming a catalyst (5) for electrocatalysis. The method (1, 10) comprises contacting s1 a catalyst starting material (17) arranged on an electrode substrate (16) with an oxidizing agent composition (18), and at least partially oxidizing the catalyst starting material (17) by means of the oxidizing agent composition (18). The invention also relates to a catalyst (5) and a device (100) for electrocatalysis, and to the use of the catalyst (5).

Description

Technical Field

[0001] This invention relates to a method for forming a catalyst for electrocatalysis, a catalyst and apparatus for electrocatalysis, and the application of the catalyst. Background Technology

[0002] Electrochemical reduction of CO2 and / or CO is a technique that converts CO2 and / or CO into hydrocarbons such as methane, ethane, ethylene, and acetylene, and / or oxygen-containing compounds such as alcohols, aldehydes, and / or acids through electrolysis.

[0003] For this purpose, an electrolysis device can be used, which is equipped with a gas diffusion electrode as the working electrode to directly supply gaseous CO2 or CO. The gas diffusion electrode is permeable to the gas but impermeable to the liquid electrolyte. At the same time, the working electrode is conductive and equipped with a solid catalyst, so that electrochemical reduction of CO2 or CO can occur at a high current density at the three-phase boundary between the catalyst, CO2 or CO and the electrolyte.

[0004] Catalysts are crucial for the product selectivity and stability of electrolytic processes. Highly specialized nanomaterials are used as catalysts. However, they have several drawbacks. First, they are typically complex to manufacture, can only be produced in small quantities, and are therefore very expensive. Second, nanomaterials are limited by low storage stability in most cases. Over time, the materials may aggregate to form larger particles or oxidize. This means that batch aging of the material can have a direct impact on the electrolytic process, affecting product distribution and stability, which is detrimental to the most reliable technology possible.

[0005] To the authors' knowledge, this problem has been largely unaddressed to date. Since the electrochemical reduction of CO2 is currently a subject of research but has not yet been applied industrially, very little work has investigated the stability of catalysts during electrocatalysis, a low-temperature method typically operating at temperatures below 100°C.

[0006] In laboratory settings, catalyst materials are typically manufactured in small batches. Short storage times mean aging is not a problem. This approach is uneconomical for future industrial-scale applications. Studies are known that rely on in-situ generation of catalyst structures via electrochemical means, i.e., in an electrolytic cell. However, to the knowledge of the inventors of this invention, these methods are limited to the use of cost-intensive materials, such as precious metals, nanomaterials, etc. Furthermore, only CO is processed as the target product, rather than higher-value hydrocarbons such as ethylene. Moreover, instead of using gas diffusion electrodes, conventional metal foils are primarily used as the matrix.

[0007] Furthermore, as known from the literature J. Zhang, W. Luo, A. Züttel, J. Mater. Chem. A, 7, 26285–26292 (2019), doi: 10.1039 / c9ta06736a, CuO, especially CuO in nanoneedle form, is particularly suitable as a catalyst for the reduction of CO2 to hydrocarbons. The fabrication of a gas diffusion electrode with a copper-based catalyst is described in this publication. In the first method step, a copper mesh is first subjected to wet chemical oxidation, and in the second method step, it is coated with a PTFE dispersion and dried. In the third method step, it is coated with another dispersion containing PTFE and carbon black to form a gas diffusion layer. In the fourth method step, it is tempered at 350°C for 1 hour. A disadvantage here is that it is a complex four-stage method. Furthermore, the storage stability issue already mentioned in the fabricated gas diffusion electrode also exists. Summary of the Invention

[0008] Against this backdrop, the object of the present invention is to provide a method for forming a catalyst for electrocatalysis, which can at least partially solve the above-mentioned problems.

[0009] This objective is achieved through the subject matter of the independent claims. The dependent claims relate to design schemes of these solutions according to the invention.

[0010] A first aspect of the present invention relates to a method for forming a catalyst for electrocatalysis.

[0011] Electrocatalysis is a heterogeneous form of catalysis that lowers the activation energy of electrochemical reactions at the electrode surface. In electrochemical processes, it allows high currents to pass through at low overvoltages. For example, the electrolysis of CO2 and / or CO can be carried out electrocatalystically. In this regard, the catalyst formed according to the proposed method can, for example, be used in the electrolysis of CO2 and / or CO, i.e., for the electrolysis of CO2 and / or CO.

[0012] Electrocatalysis is a low-temperature method, meaning it is carried out at temperatures below 100°C. In this respect, catalysts suitable for electrocatalysis must exhibit catalytic activity at temperatures below 100°C. They differ in this respect from catalysts used in thermocatalysis, which is carried out at temperatures above 100°C, for example, in the range of 250°C to 650°C. Furthermore, catalysts used for electrocatalysis are electrically conductive or can be electrically connected.

[0013] Catalyst formation refers to the manufacture of a readily usable catalyst, i.e., an already activated catalyst. The proposed method can be used for the new formation of catalysts, i.e., the initial formation, but it can also be used to reactivate previously existing catalysts, which, for example, have become at least partially deactivated over time due to the catalytic process being performed and therefore require reactivation. Such deactivation is caused, for example, by the reduction or accumulation of catalyst materials.

[0014] Accordingly, the electrode matrix can be a component of the electrode, such as a support layer or a hydrophobic layer. The electrode matrix, together with a non-oxidized sublayer of the catalyst starting material and / or a separate current collector layer, forms the electrode.

[0015] The proposed method specifies that a catalyst starting material disposed on an electrode substrate is contacted with an oxidant composition and at least partially oxidized, and / or organic deposits on the catalyst starting material are removed. Oxidation results in the formation of a catalyst, i.e., the catalyst starting material is transformed into an activated catalyst through oxidation, thereby forming a catalyst. For example, depending on the strength of the oxidant and the temperature, the duration of oxidation can be between 5 minutes and 5 hours, preferably between 20 minutes and 1 hour.

[0016] The oxidant composition can then be removed, for example by washing with water and / or solvents such as ethanol, thereby avoiding the effect of the oxidant composition on electrocatalysis.

[0017] The oxidizing agent composition can be, in particular, an aqueous composition, such as an aqueous solution of an oxidizing agent, with additives, if necessary, for adjusting the pH value. In this regard, the oxidation to be performed can be a wet chemical oxidation.

[0018] The oxidation of catalyst starting materials can be accompanied by nanoscale structuring, which can contribute to high catalytic activity, especially due to the expanded surface area. For example, nanoparticles, nanoneedles, etc., can be formed.

[0019] Typically, only a portion of the catalyst starting material can be oxidized, for example, in a region near a surface that can directly contact the oxidant composition. If, for example, a metal catalyst starting material is used, then a portion of the metal catalyst starting material can be oxidized, thereby forming two sublayers in the initial layer of catalyst starting material: a sublayer with unoxidized metal catalyst starting material and a sublayer disposed thereon with oxidized catalyst starting material. The sublayer with unoxidized metal catalyst starting material can, for example, serve as a current collector layer for an electrode, while the sublayer with oxidized metal catalyst starting material forms the catalyst.

[0020] The method is characterized by the ability to activate the catalyst starting material, i.e., the catalyst starting material arranged on the electrode matrix, in situ, thereby forming the catalyst directly at the site of use. This solves the problem of the lack of storage stability of activated catalyst materials, as the catalyst can be formed directly at the site of use, both temporally and spatially, simultaneously with electrocatalysis. Furthermore, the proposed method involves only a few steps, thus allowing it to be performed with minimal time and equipment consumption. For example, tempering at elevated temperatures, such as above 100°C, can be omitted, meaning the method can be carried out without tempering at temperatures above 100°C. Improved operational safety is also achieved through in-situ catalyst formation, as, for example, there is no need to store and transport particulate nanomaterials.

[0021] Preferably, the catalyst formed has a large surface area with atomic-scale roughness, making it easily wettable by water.

[0022] According to various implementation variations, the method may include coating the electrode matrix with a catalyst starting material.

[0023] Before contacting the catalyst starting material with the oxidant composition, the catalyst starting material can be applied to an electrode substrate, such as a support layer or a hydrophobic layer, to obtain catalyst material disposed on the electrode substrate. This corresponds to a method step in the process of first manufacturing an electrode with a catalyst. Since catalyst starting materials generally have better handleability and higher storage stability compared to already activated catalyst material, coating the electrode substrate with catalyst starting materials is more convenient and safer than coating or otherwise disposing of already activated catalyst material on the electrode substrate.

[0024] Preferably, the electrode substrate can be coated using PVD methods, such as thermal evaporation or spraying. These methods allow for the deposition of a particularly uniform or homogeneous layer of catalyst starting material on the electrode substrate. This uniformity or homogeneity refers, for example, to the layer thickness, chemical composition, and / or morphology of the layer, which can help improve the electrode's lifespan and the stability of electrocatalysis performed using the electrode.

[0025] According to another embodiment variation, the method may include applying a binder material to a catalyst starting material that has been oxidized and, if necessary, has had residual oxidant composition cleaned off.

[0026] The adhesive material can be, for example, a resin or polymer. Preferably, the adhesive material can be an anionic or cationic ionomer, such as one based on polytetrafluoroethylene, for example, a sulfonated tetrafluoroethylene polymer, such as Nafion. ®Or ionomers with imidazole ligands, such as sustainability ® .

[0027] Adhesive materials can be applied, for example, by means of dipping or spraying, doctor blade printing, screen printing, or roll-to-roll methods.

[0028] By applying a binder material, the oxidized or activated catalyst starting material can be better fixed on the electrode surface, thereby improving the electrode's service life.

[0029] According to another embodiment variant, the catalyst starting material may be a catalyst that is at least partially deactivated.

[0030] In other words, the proposed method can be used to reactivate at least partially deactivated catalysts. Here, on the one hand, the rough surface structure can be restored by oxidation of the catalyst starting material, and / or on the other hand, organic deposits detrimental to catalysis can be oxidatively removed. In long-term use, such as in electrolysis operations, catalysts typically lose all or part of their electrocatalytic activity, for example, due to the degradation of their nanostructured surfaces. In electrolyzers, for example, for converting CO2 to ethylene, after a certain operating time, such as weeks to months, operation can be briefly interrupted, and during the maintenance phase, the nanostructures on the catalyst surface can be regenerated using the described (wet chemical) oxidation method with the aid of an oxidant composition, so that the operating phase can then be resumed with high efficiency. This process can be cyclical, for example, repeated according to a predetermined schedule or even based on product yield, which can be analyzed, for example, based on the Faraday efficiency of one or more desired electrolysis products.

[0031] Here, Faraday efficiency refers to the ratio of the portion of the electrolytic current used to produce a specific electrolytic product, i.e., the electrons released from the cathode, to the electrolytic current used to produce other electrolytic products.

[0032] Therefore, this method enables a convenient, safe, and cost-effective way to extend the total lifespan of the catalyst-equipped electrode during electrocatalysis, and allows for high-efficiency electrocatalysis over extended periods.

[0033] Depending on the various implementation variations, the electrode substrate may be a gas diffusion electrode.

[0034] Such gas diffusion electrodes can be used, for example, as working electrodes, such as as cathodes in the electrolysis of CO2 and / or CO. Catalyst starting materials can be disposed on the surface of the substrate of the gas diffusion electrode, for example, on the surface of a support layer or a hydrophobic layer.

[0035] Advantageously, the gas diffusion electrode allows for the direct supply of gaseous reactants to be electrocatalytically converted. Thus, the desired electrocatalysis can proceed continuously and efficiently in a simple manner.

[0036] According to various embodiments, the catalyst starting material may have at least one material selected from a group including copper, copper-containing compounds, silver, silver-containing compounds, gold, gold-containing compounds, lead, lead-containing compounds, zinc, zinc-containing compounds, tin, and tin-containing compounds.

[0037] Compounds containing copper, silver, gold, lead, zinc, or tin are, for example, oxides of copper, silver, gold, lead, zinc, or tin, or alloys thereof with other metals, or alloys thereof with each other, and / or alloys thereof with gold, ruthenium, and / or non-precious metals. Of course, the catalyst starting material can include a variety of the materials mentioned above.

[0038] Preferably, the catalyst starting material may include copper, thereby forming a copper-containing catalyst. Copper-containing catalysts have proven to be particularly effective for electrocatalysis, especially in the electrocatalytic conversion of CO2 and / or CO into high-value hydrocarbons and / or oxygen-containing compounds, because such catalysts are capable of significantly establishing C-C bonds.

[0039] More preferably, the catalyst starting material may be metallic copper or composed of metallic copper. Metallic copper is characterized by its high electrical conductivity, thus it can be applied to the electrode substrate by spraying or deposition, for example, using common spraying and vapor deposition methods. Furthermore, the catalyst starting material having or being composed of metallic copper can also serve as a current collector layer for the electrode. This means that the lower sublayer, i.e., the one disposed on the electrode substrate, having or being composed of metallic copper, can be retained and form a current collector layer, while the upper sublayer disposed thereon can be oxidized into a catalyst using an oxidant composition.

[0040] According to other embodiments, the oxidant composition may have at least one composition selected from a group including aqueous solutions of ammonium persulfate and sodium hydroxide, aqueous solutions of hydrogen peroxide, aqueous solutions of perchlorate, aqueous solutions of nitric acid and sulfuric acid.

[0041] Of course, the oxidizing agent composition can include a variety of compositions.

[0042] The aforementioned compositions, particularly when combined with copper-containing catalyst starting materials, can promote oxidation and form nanostructures, such as nanoneedles, that are particularly suitable for electrocatalysis.

[0043] According to another embodiment variant, the oxidation of the catalyst starting material can be carried out without applying an electric potential.

[0044] Compared to methods that induce oxidation by applying an electrical potential, the proposed method involves oxidation using an oxidant composition, particularly wet chemical oxidation. Such oxidation is easier to control and can yield structures exhibiting higher catalytic activity. This can be carried out in the early stages of manufacturing, before the electrical connection to the gas diffusion electrode exists. Furthermore, oxidation using the oxidant composition can clean the catalyst material, as it oxidatively removes any potential surface organic contaminants that could lead to reduced activity.

[0045] A second aspect of the invention relates to a catalyst for electrocatalysis that can be obtained by any of the methods described above.

[0046] Therefore, the discussion above used to explain these methods also applies to the description of the proposed catalyst. The advantages of the methods are correspondingly associated with the proposed catalyst.

[0047] These catalysts are characterized by their nanostructures, such as nanoneedle-like structures, which help improve catalytic selectivity.

[0048] Another aspect of the invention relates to the application of catalysts formed according to any of the methods described above, or catalysts that can be obtained by such methods, for electrocatalysis.

[0049] Therefore, the discussion above used to explain these methods also applies to describing the proposed applications. The advantages of the methods are correspondingly associated with the proposed applications.

[0050] In particular, electrocatalysis can be carried out during the electrolysis of CO2 and / or CO.

[0051] Another aspect of the invention relates to an apparatus for electrocatalysis, the apparatus having a catalyst formed according to any of the methods described above, or a catalyst that can be obtained by means of such methods.

[0052] Therefore, the discussion above used to explain these methods also applies to describing the proposed apparatus. The advantages of the methods are correspondingly associated with the proposed apparatus.

[0053] The electrolysis apparatus may preferably have a gas diffusion electrode, which is provided with the formed catalyst. In other words, the catalyst may be formed on the gas diffusion electrode.

[0054] In particular, the device can be configured to electrolyze CO2 and / or CO, i.e., it can be an electrolysis device. Attached Figure Description

[0055] The features, characteristics, and advantages of the present invention, as well as the ways in which they are implemented, described above will become clearer and more explicit in conjunction with the following description of the embodiments, which will be explained in more detail with reference to the accompanying drawings, in which the following drawings are shown:

[0056] Figure 1 A flowchart of an exemplary method;

[0057] Figures 2A to 2C A schematic diagram of the fabrication of an exemplary gas diffusion electrode with a catalyst;

[0058] Figure 3 A schematic diagram of an exemplary electrolysis apparatus;

[0059] Figure 4 Adopted according to Figure 2C A graph showing the changes in the Faraday efficiency and current density components of the CO2 electrolysis products over 20 hours at a gas diffusion electrode under a constant potential relative to Ag / AgCl (3M) -1.6V; and

[0060] Figure 5 A flowchart of another exemplary method. Detailed Implementation

[0061] refer to Figure 1 The following explains an exemplary method 1 for forming catalyst 5 for electrocatalysis. Here, catalyst 5 is formed on a gas diffusion electrode 23. Method 1 relates to the initial fabrication of catalyst 5. Method 1 proposes to produce a highly functional, nanostructured catalyst layer in a cost-effective manner and only when needed, by controlled oxidation of a conventional copper layer in a wet chemical process. Figure 2 shows the associated gas diffusion electrode 23 (bottom of Figure 2) and intermediate steps in its fabrication.

[0062] Following the commencement of Method 1, in Method Step S0, the electrode matrix 16 is coated with a catalyst starting material 16. In this embodiment, the electrode matrix 16 is a carrier layer 20, on which a porous hydrophobic layer 21 is disposed. The carrier layer 20 is configured to be mechanically stable and may include fibers, such as in the form of woven fabrics, braided fabrics, knitted fabrics, or crocheted fabrics. The carrier layer 20 and the hydrophobic layer 21 are configured to be porous so that gaseous reactants can be supplied and gaseous products discharged through layers 20 and 21 when using the gas diffusion electrode 23.

[0063] In method step S0, the surface of the hydrophobic layer 21 is coated with catalyst starting material 17 by means of thermal evaporation. In this embodiment, inexpensive conventional copper particles are used as the raw material for thermal evaporation, thereby forming a metallic copper layer as catalyst starting material 17. Figure 2A The corresponding state after the end of method step S0 is shown, wherein the catalyst starting material 17 is arranged on the electrode matrix 16.

[0064] It should be noted that the hydrophobic layer 21 is only optionally present to prevent the intrusion of liquid aqueous electrolyte when using the gas diffusion electrode 23. In other words, the catalyst starting material 17 can also be deposited directly on the support layer 20, for example. Alternatively, other catalyst starting materials 17 can be used to coat the electrode matrix 16.

[0065] In subsequent method step S1, the catalyst starting material 17 disposed on the electrode substrate 16 is brought into brief contact with, for example, immersed in, the oxidant composition 18. "Brief contact" means a time period between 20 minutes and 1 hour, for example, approximately 45 minutes. This is shown in Figure 2 by a square arrow marked "+18". In method step S3, the catalyst starting material 17 is partially oxidized by means of the oxidant composition 18. No potential is applied during this period.

[0066] In this embodiment, an aqueous solution consisting of ammonium persulfate and sodium hydroxide is used as the oxidant composition 18.

[0067] Two sublayers were obtained by partially oxidizing the catalyst starting material 17. The lower sublayer, directly disposed on the hydrophobic layer 21, retains its initial non-oxidized state due to insufficient contact with the oxidant composition 18, i.e., it serves as a metallic copper layer. This sublayer forms a conductive current collector 22 for the gas diffusion electrode 23. The purpose of the current collector 22 is to achieve good conductivity in a plane, thereby allowing contact with the gas diffusion electrode 23 from the edge.

[0068] The uppermost second sublayer is composed of oxidized catalyst starting material 17 and forms catalyst 5. In this embodiment, catalyst starting material 17 is treated with oxidant composition 18 nanoneedles formed of copper(II) oxide (CuO), which is particularly suitable as catalyst 5 for reducing CO2 to hydrocarbons by electrolysis. Figure 2B The corresponding state after the end of method step S2 is shown.

[0069] In step S3, the oxidant composition 18 is removed by cleaning and washing away any residue of the oxidant composition 18 with water or a solvent (not shown in Figure 2).

[0070] Optionally, method 1 may continue with method step S4, in which the binder material 19 is applied to the oxidized catalyst starting material 17, i.e., the formed catalyst 5. In this embodiment, a perfluorosulfonic acid polymer (Nafion) is used. ®The binder material 19 is used as the binder material. This is shown in Figure 2 by a square arrow marked "+19". With the aid of the binder material 19, nanoparticles composed of copper oxide (II) are fixed onto the current collector layer 22, thereby obtaining the gas diffusion electrode 23 (…). Figure 2C It is immediately available and can be used, for example, for electrocatalysis in the electrolysis of CO2 and / or CO. Method 1 ends after step S4.

[0071] Figure 3 A schematic diagram of an exemplary electrolysis apparatus 100 is shown, in which a gas diffusion electrode 23 is used as a cathode 3.

[0072] Electrolysis apparatus 100 has an electrolytic cell 2, which has a cathode chamber 6 and an anode chamber 7, which are separated from each other by a membrane 8, wherein the membrane 8 may contain, for example, a perfluorinated copolymer with sulfonic acid groups, also known as Nafion. ® As is known, a cathode 3 is arranged in a cathode chamber 6 and an anode 4 is arranged in an anode chamber 7, wherein the cathode 3 and the anode 4 are connected to a power supply device 17.

[0073] For electrolysis, CO2 and / or CO are supplied to the cathode chamber 6 through the gas inlet 9, where they are reduced at the cathode 3 to the desired electrolysis products, also known as valuable products, such as ethylene, and can be discharged from the cathode chamber 6 through the product outlet 11.

[0074] An aqueous electrolyte 18 is present in the anode chamber 7, and oxygen is formed from this aqueous electrolyte at the anode 4. An aqueous electrolyte 18 is also present in the cathode chamber 6, and its composition may be the same as or different from that of the aqueous electrolyte in the anode chamber 7.

[0075] In this embodiment, the cathode 3 or working electrode is the gas diffusion electrode 23 of FIG2. The copper-containing catalyst 5 of the gas diffusion electrode 23 catalyzes the desired electrolysis reaction.

[0076] Figure 4 The Faraday efficiency FE of the products of CO2 electrolysis is shown using the gas diffusion electrode 23 according to Figure 2. Figure 4 (upper part) and current density component j ( Figure 4 The diagram below illustrates the changes. Here, CO2 electrolysis was carried out for 20 hours at a constant potential of -1.6V relative to Ag / AgCl (3M).

[0077] Symbols -j and j eff This represents the same physical quantity, namely the current actually used to form one or more specific products, which is neither used for other products nor lost due to parasitic conductivity. To determine -j or j... effThe method measures the number of specific types of molecules formed per unit time (the ratio of exhaust gas flow to each gas). The number of electrons required to form a molecule, i.e., the charge required for each molecule, can be determined from the chemical reaction equation. From this, the current component used to form the molecule can be calculated and used as the current density (the area of ​​the electrolytic electrode).

[0078] The figure shows that the gas diffusion electrode 23 exhibits excellent selectivity for ethylene (C2H4), with a nearly constant high Faraday efficiency of approximately 50% observed for ethylene over 20 hours, while the Faraday efficiency for the undesirable byproduct hydrogen only slightly increases from approximately 8% to approximately 20%. The current density component j behaves accordingly.

[0079] exist Figure 5 A flowchart of another exemplary method 10 for forming catalyst 5 for electrocatalysis is shown in the figure. (Refer to...) Figure 1 Unlike method 1 described in Figure 2, in Figure 5 In this process, catalyst 5 is not newly manufactured, but rather a reactivation of an existing, partially deactivated copper-based catalyst 5. The partially deactivated catalyst 5 here refers to catalyst starting material 17. For example, using a catalyst 5 newly formed according to method 1 for the electrolysis of CO2 and / or CO, after, for example, several weeks or months of electrolysis operation, the catalyst can be reactivated using method 10.

[0080] Following the commencement of method 10, method steps S1 to S3 of method 10 are performed similarly to those of method 1, namely, the partially deactivated catalyst 5, serving as the catalyst initiating material 17, is contacted with the oxidant composition 18 and at least partially oxidized, thereby forming nanoneedles composed of cuprous oxide (I). In method step S3, the oxidant composition 18 is removed, and method 10 is subsequently terminated. The catalyst 5, and more specifically the gas diffusion electrode 23 provided therewith, can now be used again for highly selective electrolysis of CO2 and / or CO to obtain desired valuable products, such as ethylene.

[0081] Methods 1 and 10 described are cost-effective because they use only conventional copper particles as the raw material for catalyst 5. Furthermore, they are associated with relatively low time consumption. Instead of complex catalyst synthesis and the steps of applying catalyst 5 to the current collector 22, both are carried out simultaneously in a single, time-efficient step in the described methods.

[0082] Perhaps the greatest advantage is that it eliminates the need for storage of nanomaterials. As already explained, nanomaterials frequently undergo aging over time. Therefore, the use of nanomaterials is limited to uneconomical small-batch production or is still subject to catalyst changes over time. Complex storage under a protective gas atmosphere can appropriately slow down aging, but it is also costly and cannot completely prevent aging. In the proposed methods 1 and 10, nanomaterials are produced immediately before use as needed, thus completely avoiding aging due to storage.

[0083] In the electrochemical reduction of CO2, a current density close to that used in practical applications (typically 200-800 mA / cm²) is employed. 2 When electrolyzing (on the geometric electrode surface), the catalyst 5 formed by methods 1 and 10 exhibits high selectivity for ethylene and is at least equivalent to conventional catalysts in this respect.

[0084] Although the invention has been illustrated and described in more detail by way of preferred embodiments, the invention is not limited to the disclosed examples, and other variations can be derived by those skilled in the art without departing from the scope of protection of the invention.

[0085] In summary, the present invention relates to methods 1 and 10 for forming a catalyst 5 for electrocatalysis. Methods 1 and 10 include contacting a catalyst starting material 17 disposed on an electrode substrate 16 with an oxidant composition 18 S1, and at least partially oxidizing the catalyst starting material 17 by means of the oxidant composition 18.

[0086] Furthermore, the present invention also relates to a catalyst 5 and an apparatus 100 for electrocatalysis, and the application of the catalyst 5. List of reference numerals in the attached diagram: 1. Method 2 Electrolytic Cell 3 Cathode 4 Anode 5 catalysts 6. Cathode Chamber 7 Anode Chamber 8. Membrane 9 Gas Inlet 10 methods 11. Product Exports 12. Gaseous products 13 Liquid products 14 Power supply equipment 15. Aqueous electrolytes 16 Electrode substrate 17 Catalyst Starting Materials 18 Oxidizing Agent Composition 19 Adhesive materials 20 Carrier Layer 21 Hydrophobic layer 22. Combustion Layer 23 Gas diffusion electrode 100 devices S0 uses catalyst starting materials to coat the electrode matrix. S1 brings the catalyst initiator material arranged on the electrode substrate into contact with the oxidant composition. S2 oxidizes the catalyst starting material at least partially with the aid of an oxidant composition. S3 Oxidant Removal Composition S4 applies a binder material to the oxidized catalyst starting material.

Claims

1. A method (1, 10) for forming a catalyst (5) for electrocatalysis, said method (1) comprising: - S1: Contact the catalyst starting material (17) arranged on the electrode substrate (16) with the oxidant composition (18), and - S2: The catalyst starting material (17) is at least partially oxidized and / or organic deposits on the catalyst starting material are removed by means of the oxidant composition (18).

2. The method (1) according to claim 1, comprising: - S0: Coat the electrode matrix (15) with the catalyst starting material (16).

3. The method (1) according to claim 2, wherein, The electrode substrate (16) is coated using a PVD method.

4. The method (1) according to any one of the preceding claims, wherein, The method includes: - S4: Apply the binder material (19) to the oxidized catalyst starting material (17).

5. The method (10) according to claim 1, wherein, The catalyst starting material (17) is at least partially deactivated catalyst (5).

6. The method (1, 10) according to any one of the preceding claims, wherein, The electrode substrate (16) is a gas diffusion electrode.

7. The method (1, 10) according to any one of the preceding claims, wherein, The catalyst starting material (17) has at least one material selected from a group including copper, copper-containing compounds, silver, silver-containing compounds, gold, gold-containing compounds, lead, lead-containing compounds, zinc, zinc-containing compounds, tin, and tin-containing compounds.

8. The method (1, 10) according to any one of the preceding claims, wherein, The oxidant composition (18) has at least one composition selected from a group including an aqueous solution of ammonium persulfate and sodium hydroxide, an aqueous solution of hydrogen peroxide, an aqueous solution of perchlorate, an aqueous solution of nitric acid, and an aqueous solution of sulfuric acid.

9. The method (1, 10) according to any one of the preceding claims, wherein, The oxidation of the catalyst starting material (17) is carried out without applying an electric potential.

10. The method (1, 10) according to any one of the preceding claims, wherein, The oxidation lasts for between 5 minutes and 5 hours, preferably between 20 minutes and 1 hour.

11. A catalyst (5) for electrocatalysis, said catalyst being obtained by the method (1, 10) according to any one of claims 1 to 10.

12. The catalyst (5) formed according to any one of the methods (1, 10) according to claims 1 to 10 or the catalyst (5) according to claim 11 is used for electrocatalysis.

13. The application according to claim 12, wherein, Electrocatalysis is performed during the electrolysis of CO2 and / or CO.

14. An apparatus (100) for electrocatalysis, the apparatus (100) having a catalyst (5) formed according to any one of claims 1 to 9 or a catalyst (5) according to claim 11.

15. The apparatus (100) according to claim 14, wherein, The catalyst (5) is formed on the gas diffusion electrode (23).

16. The apparatus (100) according to claim 14 or 15, wherein, The device is configured to electrolyze CO2 and / or CO.

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