Catalyst layer for alkaline electrolysis

Abstract

The present invention relates to a precursor for the production of an alloy used as a catalyst. The precursor comprises a metallic substrate, a layered structure comprising binders, metallic particles, and at least one metal oxide, metal phosphide, and / or metal sulfide, wherein the layered structure is arranged on the metallic substrate.

Description

[0001] The present invention relates to a precursor for the production of an alloy used as a catalyst. The precursor comprises a metallic substrate, a layered structure comprising binders, metallic particles, and at least one metal oxide, metal phosphide, and / or metal sulfide, wherein the layered structure is arranged on the metallic substrate.

[0002] The catalytic production of hydrogen is a significant process in the chemical industry, gaining importance primarily due to the increasing demand for clean energy and the need to reduce greenhouse gas emissions. The main methods for catalytic hydrogen production are steam reforming of natural gas, partial oxidation, autothermal reforming, electrolysis, and photocatalytic water splitting. Currently, four main technologies are distinguished for the electrolysis of water to hydrogen: alkaline electrolysis (AEL), proton exchange membrane electrolysis (PMEL), high-temperature electrolysis (HTEL), and anion exchange membrane electrolysis (AEMEL).

[0003] The most commonly used commercial electrolysis technology is AEL. In this process, two metallic electrodes are immersed in an alkaline aqueous solution, the so-called electrolyte. Applying a direct current voltage then initiates the electrolytic splitting of the water, and hydrogen and hydroxide ions are produced as reaction products at the cathode (negatively charged).

[0004] Alkaline electrolysis is a proven technology with relatively low operating costs. Expensive precious metal catalysts are not required, as less expensive metal catalysts are sufficient. On the other hand, its efficiency is somewhat lower compared to alternative electrolysis methods. Currently, alkaline electrolysis is the preferred method for producing green hydrogen, where the electricity required for electrolysis comes from renewable energy sources.

[0005] The object of the invention is to provide electrode materials that are as inexpensive as possible, exhibit the highest possible catalytic activity, and offer the highest possible long-term stability. Currently, Raney nickel electrodes are commonly used for AELs. Raney nickel electrodes have an increased surface area due to a special porous or sintered structure. This increased surface area provides more active regions for electrochemical reactions, thus increasing the efficiency of hydrogen production. Depending on the coating, either the catalytic activity, the surface area of ​​the catalyst, and / or its lifespan can be enhanced.

[0006] Surprisingly, it has now been found that the alloys according to the invention can improve not only the catalytic activity but also the long-term stability of the electrode material. Without being bound to any theory, the inventive method can increase the surface area of ​​the electrodes, thereby increasing the catalytic activity, and simultaneously stably incorporate catalytically active particles into this structure.

[0007] In a first aspect, the invention therefore relates to a precursor comprising (i) a metallic substrate, in particular a nickel, iron or copper substrate and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 metallic particles, in particular aluminium, tin, silicon, iron and / or copper particles, and (ii)-3 at least one metal oxide, metal phosphide and / or metal sulfide, the layered structure is arranged on the metallic substrate.

[0008] The metallic substrate (i) is preferably a nickel, iron, or copper substrate, particularly a nickel substrate. The metallic substrate is preferably in the form of a film, fabric, sheet, perforated sheet, expanded metal, foam, particles, or plate. Preferably, the metallic substrate is porous and has a porosity of 1–70%, more preferably 10–50%, measured according to DIN ISO 9277.

[0009] The metallic substrate, in the form of a film, fabric, sheet, perforated sheet, expanded metal, or plate, preferably has a thickness of 0.01–5 mm, more preferably 0.1–2 mm. If the metallic substrate is in the form of particles, the average particle diameter is preferably in the range of 2–72 µm, more preferably 7–63 µm. The particle size distribution d50 is preferably in the range of 20–45 µm, more preferably in the range of 25–40 µm.

[0010] The metallic substrate preferably has a purity of at least 90%, preferably 99 wt.%, more preferably 99–99.9 wt.%. In alternative embodiments, the metallic substrate can also be an alloy, preferably an iron alloy, in particular stainless steel, e.g., Fe-Cr-Ni-Mo or Fe-Cr-Ni alloy.

[0011] The layered structure (ii) comprises (ii)-1 at least one binder. The binder is preferably an organic binder, more preferably an organic polymer, such as polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polypyrrole, or polyvinylpyrrolidone. The weight-average molecular weight of the organic polymer is preferably 1,000–40,000 g / mol.

[0012] The layered structure (ii) further comprises metallic particles. The metallic particles are preferably made of aluminum, tin, silicon, iron, and / or copper. Aluminum or aluminum / tin particles are preferably used. The metallic particles (ii)-2 preferably have a mean particle diameter of 1–70 µm, more preferably 4–32 µm. The particle size distribution d50 of the metallic particles (ii)-2 is preferably in the range of 20–60 µm, more preferably 20–35 µm.

[0013] Preferably, the metallic substrate (i) is different from the metallic particle (ii)-2. In a preferred embodiment, the metallic substrate is a nickel substrate and the metallic particles are aluminum or aluminum / tin particles.

[0014] The layer structure further comprises at least one metal oxide, metal phosphide and / or metal sulfide (ii)-3.

[0015] The metal oxide preferably has a cubic, orthorhombic, or tetragonal crystal structure, more preferably a perovskite or spinel structure. Preferably, the metal oxide has the formula ABO₃, AB₂O₄, or A₂B₂O₆, wherein A is at least one metal cation selected from Li, Na, K, Ca, Rb, Sr, Y, Ba, Ag, Bi, La, Ce, Pr, Nd, Sm and Gd cations, preferably La, Sr, Ba and Ca cations, and B is at least one metal cation selected from Mg, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Al, Ge, Zr, Nb, Mo, Ru, Pd, Cd, In, Sn, Sb, Ta and Ir cations, preferably Cr, Mn, Fe, Co, Ni, Ru, Pd ions.

[0016] If component (ii)-3 is a metal sulfide, it is preferably in a stannite, Cu 2 FeSnS 4 -, Cu 2 CoSnS 4 -, Ag 2 ZnSnS 4 - structure.

[0017] If component (ii)-3 is a metal phosphide, it is preferably in a NiP, Ni 2 P, CoP, Co 2 P or Co 3 BPO 7 structure.

[0018] Component (ii)-3 preferably has a mean particle diameter of 1 nm - 44 µm, more preferably 10 nm - 10 µm, and even more preferably 10 nm - 1 µm. The particle size distribution d50 of component (ii)-3 is preferably in the range of 50 nm - 10 µm, and more preferably 50 nm - 500 nm.

[0019] The layer structure (ii) preferably comprises 1-50 wt.%, more preferably 20-35 wt.% of component (ii)-2 based on the total weight of the layer structure. Preferably, the layer structure contains 0.1-50 wt.%, more preferably 0.1-10 wt.% of component (ii)-3 based on the total weight of the layer structure. Preferably, the sum of components (ii)-1, (ii)-2, and (ii)-3 together constitutes 100 wt.% of the layer structure.

[0020] Furthermore, the layer structure preferably contains 0.1–20 wt.%, more preferably 1–10 wt.% binder based on the total weight of the layer structure. The weight ratio of components (ii)-2:(ii)-3 is preferably 500:1–4:1, more preferably 100:1–9:1.

[0021] The layer structure is preferably 100 nm-700 µm, more preferably 1-500 µm.

[0022] In a preferred embodiment, the precursor comprises (i) a metallic nickel substrate and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 aluminium particles and / or aluminium / tin particles and (ii)-3 at least one metal oxide, preferably in a cubic, orthorhombic or tetragonal crystal structure, the layered structure is arranged on the metallic nickel substrate.

[0023] In a preferred embodiment, the layer structure comprises a single layer. Preferably, the metallic particles (ii)-2 and component (ii)-3 are homogeneously embedded in the binder matrix within this single layer. This single layer preferably has a thickness of 100 nm to 700 µm, more preferably 1 to 500 µm.

[0024] Alternatively, the layer structure (ii) comprises several layers, in particular two layers, e.g., α and β. In this case, layer α preferably comprises at least one binder and component (ii)-3. Layer β preferably comprises at least one binder and component (ii)-2. Preferably, component (ii)-3 in layer α and (ii)-2 in layer β is homogeneously distributed in the binder. Layer α is preferably arranged on the metallic substrate (i), and layer β is preferably arranged on top of layer α. The thickness of layer α is preferably in the range of 1–100 µm, more preferably 10–70 µm. The thickness of layer β is preferably in the range of 1–500 µm, more preferably 50–300 µm.

[0025] Layer α preferably contains 1-40 wt% of component (ii)-3 based on the total weight of layer α.

[0026] The layer β preferably contains 1-35 wt% of component (ii)-2 based on the total weight of the layer β.

[0027] The weight fraction and the ratio of components (ii)-2 and (ii)-3 are also preferred in the two-layer structure as described above.

[0028] Another aspect of the invention lies in a method for producing the precursor according to the invention, comprising the steps (a) Providing a metallic substrate, in particular a metallic nickel substrate, (b) Applying a suspension comprising binder, solvent, component (ii)-3 and optionally component (ii)-2, (c) Removing the solvent, optionally at elevated temperature, to form a layer, (d) Optionally applying a suspension comprising binder, solvent and component (ii)-2 to the layer obtained after step (c), (e) Optionally removing the solvent, optionally at elevated temperature, to form a layer β.

[0029] The metallic substrate in step (a) corresponds to component (i) as described above. The binder corresponds to the binder as described above. Preferably, water or an organic solvent is used, preferably one capable of completely dissolving the binder at 23 °C. Suitable organic solvents include, for example, isopropanol, acetone, dimethylformamide, butanol, ethanol, or a mixture thereof.

[0030] Preferably, the suspension in step (b) contains binder, solvent, component (ii)-2 and component (ii)-3.

[0031] Alternatively, the suspension in step (b) contains binder, solvent, component (ii)-3, and no component (ii)-2. In the latter case, however, step (d) is not optional but essential, with the suspension in step (d) containing binder, solvent, and component (ii)-2. In step (c), a layer α is formed if the suspension in step (b) does not include component (ii)-2.

[0032] The suspensions in steps (b) and (d) are preferably storage-stable, i.e., they do not separate over a longer period of time, e.g., at least one week, at least one month, or at least six months, i.e., they remain homogeneous. The viscosity of the suspensions in steps (b) or (d) can be adjusted, e.g., by the type of solvent / binder mixture.

[0033] The suspensions are applied to the substrate by methods known to those skilled in the art, e.g., by spraying, brushing, or dipping. In steps (c) and (d), the solvent is then substantially removed. This can be carried out at elevated temperature, for example, at 20–120 °C, preferably 20–70 °C, e.g., at a pressure of e.g., 0.001–1 bar.

[0034] The layer formed after step (c) preferably has a thickness of 100 nm - 700 µm, more preferably of 1-500 µm, more preferably 20-200 µm.

[0035] The layer formed after step (e), e.g. layer β, preferably has a thickness of 10-500 µm, more preferably of 20-200 µm.

[0036] Preferably the suspension contains in step (b) 50-75 wt.% solvent, 1-10 wt.% binder, 20-35 wt.% component (ii)-2 and optionally 0.1-10 wt.% component (ii)-3.

[0037] The suspension in step (d) preferably contains 50-75 wt.% solvent, 1-10 wt.% binder, and 20-35 wt.% component (ii)-2.

[0038] Another aspect of the invention is a precursor obtainable by the method described above.

[0039] The precursor described above can be used to produce a catalyst.

[0040] Another aspect of the present invention is an alloy comprising (I) a metallic substrate, in particular a metallic nickel substrate, (II) at least one alloy comprising the metal according to (I) and (III) at least one porous alloy comprising the metal according to (I) in which at least one metal oxide, metal phosphide and / or metal sulfide is intercalated.

[0041] The alloy is more preferably included (I) a substrate of metallic nickel, (II) at least a nickel-aluminium alloy and (III) at least a porous nickel-aluminium alloy in which at least one metal oxide is intercalated.

[0042] The metallic substrate, metal oxide, metal phosphide, and metal sulfide are as defined above. The alloy (II) is preferably arranged on the substrate (I), and the porous alloy (III) is preferably arranged on the alloy (II). The alloy (II) preferably has a different composition than the porous alloy (III).

[0043] The alloy (II) preferably has a different composition than the porous alloy (III).

[0044] The alloy can be in the form of films, sheets, perforated sheets, expanded metal, foams, particles, plates, or fabrics. Preferably, the alloy has a specific surface area of ​​0.2–10 m² / g, more preferably 5–10 m² / g, measured according to DIN ISO 9277.

[0045] The alloy (II) preferably has an average thickness of 1-200 µm, more preferably 1-60 µm. The porous alloy (III) preferably has an average thickness of 1-300 µm, more preferably 1-200 µm.

[0046] Preferably the alloy (II) comprises Ni 2 Al 3 and / or NiAl 3 .

[0047] The metal oxide, metal phosphide, and / or metal sulfide is as described above. The metal oxide, metal phosphide, and / or metal sulfide is embedded in the porous alloy, preferably by physical and / or chemical, more preferably by physical interactions.

[0048] It has been shown that the intercalation or incorporation of metal oxides, metal phosphides and / or metal sulfides can further improve the catalytic effect of the alloy without impairing the long-term catalytic stability.

[0049] In another aspect, the invention relates to a method for producing the alloy according to the invention, comprising the steps (A) Providing a precursor according to the invention, (B) Treating the precursor at temperatures ≥ 600 °C, preferably 600-800 °C for a duration preferably 1-300 minutes, more preferably 1-180 minutes, (C) Treating the product obtained after step (B) in alkaline solution, preferably at elevated temperature, and (D) optionally washing and drying the product obtained after step (C).

[0050] In step (B), an alloy is formed by fusing the metallic substrate and the metallic particles. Simultaneously, the binder of the precursor is pyrolyzed. By treating the product obtained after step (B) in alkaline solution, some alloy phases dissolve more readily than others, resulting in a porous structure in which component (ii)-3 is incorporated.

[0051] In the case of nickel substrates and aluminum particles, for example, the nickel-aluminum phases Ni₂Al₃, NiAl₃, and Al-NiAl₃ form on the surface of the nickel substrate. While the NiAl₃ alloy is readily soluble in alkaline solutions, a porous alloy forms from the remaining alloy phases, which are less soluble in alkaline solutions.

[0052] The product obtained after step (C) can optionally be washed and dried or used directly as an electrode in an electrolysis cell.

[0053] A suitable alkaline solution is preferably a 1-8 molar alkali hydroxide solution in water, in particular sodium hydroxide or potassium hydroxide solution. To accelerate the process, step (C) can be carried out at an elevated temperature, e.g., at 20-80 °C.

[0054] Another aspect of the invention is the alloy obtained by the method described above.

[0055] The alloy according to the invention can be used as a catalyst and / or electrode, particularly in alkaline electrolysis. Surprisingly, it has been shown that the catalytic effect of the electrode material can be improved compared to non-intercalated electrodes without affecting the long-term stability of the catalyst. Baseball Materials:

[0056] Substrate Metallics: Nickel 99.9 %. Metallische Particle (ii)-2: Aluminum particles with a Zinngehalt content of less than 5%. d50: 16 µm Metalloxide (ii)-3: The 0.2 Sr 0.8 FeO 3 ; and 50 8 μm The 0.5 Sr 0.5 Ni 0.4 Fe 0.6 O 3 ; and 50 10 μm The 0.9 Sr 0.05 CoO 3 ; and 50 7.5 μm Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 , d 50 2.1 μm Sr 0.95 Co 0.8 Fe 0.2 O 3 -δ; and 50 5.3 μm LaCo0.75Ni 0.25 O 3 , d 50 2.5 µm Ba 0.5 Sr 0.5 Co 0.85 Fe 0.6 Ni 0.15 O 3 , d 50 6.5 µm LaNiO 3 , and 50 4.2 μm LaCoOs; and 50 10.4 μm Herstellung des Pioneers

[0057] Metal oxide, phosphide, or sulfide was produced by sol-gel synthesis (Pecchini method) through the reaction of separate metal salt solutions in suitable solvents (e.g., isopropanol), optionally with the addition of complexing agents (e.g., citric acid), at specific pH values ​​and thermally processed. The processes are known to those skilled in the art. The binder is a mixture of 18–21 wt% PVA, 75–81 wt% PVB, and 1–4 wt% polyvinyl acetate, which dissolves completely in a binder:solvent [isopropanol] ratio of 1:10 or higher. 20–30 wt% aluminum particles are added to the solution. 5–20 mg / cm² of the resulting suspension are applied to the substrate (perforated sheet metal, expanded metal; thickness up to 0.01 to 1 mm) by spray coating. Herstellung der Legierung

[0058] The resulting precursor is thermally treated above the sintering temperature of aluminum, from T ≥ 0.7 TS,Al (= 640 °C) to approximately 850 °C. The aluminum and metal oxide particles diffuse into the metallic substrate. After cooling, the resulting product is leached with a 0.1 to 8 M alkaline solution, preferably 7.4 M KOH, optionally with the addition of complexing agents such as potassium sodium tartrate tetrahydrate, for 2–12 hours at an elevated temperature of 40–90 °C. This process leaches out, in particular, the NiAl₃ and Ni₂Al₃ phases formed during the thermal treatment. Porous structures are obtained in which the metal oxide particles are stably embedded.

[0059] The present invention comprises the following points: 1. A precursor comprising (i) a metallic substrate, in particular a nickel, iron, or copper substrate, and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 metallic particles, in particular aluminum, tin, silicon, iron, and / or copper particles, and (ii)-3 at least one metal oxide, metal phosphide, and / or metal sulfide, wherein the layered structure is arranged on the metallic substrate. 2. A precursor according to point 1, wherein the metallic substrate (i) is different from component (ii)-2. 3. A precursor according to point 1 or 2, comprising (i) a metallic nickel substrate and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 aluminum particles, and (ii)-3 at least one metal oxide, preferably in a cubic, orthorhombic, or tetragonal crystal structure, wherein the layered structure is arranged on the metallic nickel substrate. 4.5. Precursor according to any of the preceding points, wherein the metallic substrate is in the form of a film, sheet, perforated sheet, fabric, expanded metal, foam, particle, or plate and is preferably porous. 6. Precursor according to point 4, wherein the metallic substrate has a porosity of 1 to 70%, preferably 10 to 50%, measured according to DIN ISO 9277. 7. Precursor according to point 4 or 5, wherein the film, plate, perforated sheet, fabric, or sheet has a thickness of 0.01 to 5 mm, preferably 0.1 to 2 mm. 8. Precursor according to point 4, wherein the average particle diameter is in the range of 2 to 72 µm, preferably 7 to 63 µm. 8. Precursor according to point 4 or 7, wherein the particle size distribution d50 is in the range of 20-45 µm, preferably 25-40 µm. 9. Precursor according to any of the preceding points, wherein the metallic substrate, in particular metallic nickel substrate, is present in a purity of at least 99 wt.%, preferably 99-99.9 wt.%. 10.11. Precursor according to any one of the preceding points, wherein the binder is an organic binder, in particular an organic polymer, such as polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polypyrrole, or polyvinylpyrrolidone, preferably with a weight-average molecular weight of 1,000–40,000 g / mol. 12. Precursor according to any one of the preceding points, wherein the metallic particles ((ii)–2) have a mean particle diameter of 1–70 µm, preferably 4–32 µm. 13. Precursor according to any one of the preceding points, wherein the particle size distribution d50 of the metallic particles ((ii)–2) is in the range of 20–60 µm, preferably 20–35 µm. 14. Precursor according to any one of the preceding points, wherein the metal oxide is in a perovskite or spinel structure. 14. Precursor according to any of the preceding points, wherein component (ii)-3 has a mean particle diameter of 1 nm - 44 µm, preferably 10 nm - 10 µm, more preferably 10 nm - 1 µm. 15.Precursor according to any of the preceding points, wherein the particle size distribution d50 of component (ii)-3 is in the range of 50 nm to 10 µm, preferably 50 nm to 500 nm. 16. Precursor according to any of the preceding points, wherein the metal oxide has the formula ABO 3 , AB 2 O 4 or A 2 B 2 O 6, wherein A is at least one metal cation selected from Li, Na, K, Ca, Rb, Sr, Y, Ba, Ag, Bi, La, Ce, Pr, Nd, Sm and Gd cations, preferably La, Sr, Ba and Ca cations, and B is at least one metal cation selected from Mg, Sc, Ti. V-, Cr-, Mn-, Fe-, Co-, Ni-, Cu-, Zn-, Ga-, Al-, Ge-, Zr-, Nb-, Mo-, Ru-, Pd-, Cd-, In-, Sn-, Sb-, Ta-, and Ir- cations, preferably Cr-, Mn-, Fe-, Co-, Ni-, Ru-, and Pd-ions. 17. Precursor according to any one of the preceding points, wherein the metal sulfide is in a stannite structure. 18. Precursor according to any one of the preceding points, wherein the layer structure comprises one (1) layer. 19.20. Precursor according to point 18, wherein the layer has a thickness of 100 nm–700 µm, preferably 1–500 µm. 21. Precursor according to point 18 or 19, wherein components (ii)-2 and (ii)-3 are homogeneously distributed in the layer. 22. Precursor according to any of the preceding points, wherein the layer structure contains 1–50 wt.%, preferably 20–35 wt.% of component (ii)-2 based on the total weight of the layer structure. 23. Precursor according to any of the preceding points, wherein the layer structure contains 0.1–50 wt.%, preferably 0.1–10 wt.% of component (ii)-3 based on the total weight of the layer structure. 24. Precursor according to any of the preceding points, wherein the layer structure contains 0.1–20 wt.%, preferably 1–10 wt.% binder based on the total weight of the layer structure. 24. Precursor according to any of the preceding steps, wherein the weight ratio of components (ii)-2:(ii)-3 is 500:1 to 4:1, preferably 100:1 to 9:1 in the layered structure. 25.26. Precursor according to any one of points 1-17, wherein the layer structure comprises two layers α and β. 27. Precursor according to point 25, wherein layer α comprises at least one binder and component (ii)-3. 28. Precursor according to point 25 or 26, wherein layer β comprises at least one binder and component (ii)-2. 29. Precursor according to any one of points 25-27, wherein layer α is arranged on the metallic substrate and layer β is arranged on top of layer α. 21. Precursor according to any one of points 25-28, wherein the thickness of layer α is 1-100 µm, preferably 10-70 µm. 30. Precursor according to any one of points 25-29, wherein the thickness of layer β is 1-500 µm, preferably 50-300 µm. 31. Precursor according to any one of points 25-30, wherein layer α contains 1-40 wt.% of component (ii)-3 based on the total weight of layer α. 32. Precursor according to any one of points 25-31, wherein layer β contains 1-35 wt.% of component (ii)-2 based on the total weight of layer β.33. Precursor according to any of the preceding points, wherein the layer structure has a thickness of 100 nm to 700 µm, preferably 1 µm to 600 µm. 34. Method for producing a precursor according to any of the preceding points, comprising the steps of (a) providing a metallic substrate, in particular a metallic nickel substrate, (b) applying a suspension comprising binder, solvent, component (ii)-3 and optionally component (ii)-2, (c) removing the solvent, optionally at elevated temperature, to form a layer, (d) optionally applying a suspension comprising binder, solvent and component (ii)-2 to the layer obtained after step (c), (e) optionally removing the solvent, optionally at elevated temperature, to form a layer β. 35. The method according to point 34, wherein the solvent is water or an organic solvent, e.g. isopropanol, acetone, dimethylformamide, butanol, ethanol or a mixture thereof. 36.37. A method according to paragraph 34 or 35, wherein in step (b) the suspension contains binder, solvent, component (ii)-2 and component (ii)-3. 38. A method according to any one of paragraphs 34-35, wherein, if the suspension in step (b) contains binder, solvent, component (ii)-3 and no component (ii)-2, step (d) is essential and the suspension in step (d) contains binder, solvent and component (ii)-2. 39. A method according to any one of paragraphs 34-37, wherein step (c) and optionally (e) are carried out at temperatures of 20-120 °C, preferably 20-70 °C and preferably at a pressure of 0.001-1 bar. 31. A method according to any one of paragraphs 34-38, wherein the layer formed after step (c) has a thickness of 1-500 µm, preferably 20-200 µm. 40. Method according to any one of points 34-39, wherein the layer β formed after step (e) has a thickness of 10-500 µm, preferably 20-200 µm. 41. Method according to any one of points 34-40, wherein the suspension in step (b) contains 50-75 wt.-% solvent, 1-10 wt% binder, 20-35 wt% component (ii)-2 and optionally 0.1-10 wt% component (ii)-3. 42. Process according to any one of clauses 34-41, wherein the suspension in step (d) contains 50-75 wt% solvent, 1-10 wt% binder and 20-35 wt% component (ii)-2. 43. Precursor obtainable by a process according to any one of clauses 34-42. 44. Use of a precursor according to any one of clauses 1-33 or 43 for the preparation of a catalyst. 45. Alloy comprising (I) a metallic substrate, in particular a metallic nickel substrate, (II) at least one alloy comprising the metal according to (I) and (III) at least one porous alloy comprising the metal according to (I) in which at least one metal oxide, metal phosphide and / or metal sulfide is intercalated. 46.47. Alloy according to point 45 comprising (I) a substrate of metallic nickel, (II) at least one nickel-aluminum alloy, and (III) at least one porous nickel-aluminum alloy in which at least one metal oxide is intercalated. 48. Alloy according to point 45 or 46, wherein the alloy (II) is arranged on the substrate (I) and the porous alloy (III) is arranged on the alloy (II). 49. Alloy according to any one of points 45-47, wherein the alloy (II) has a different composition than the porous alloy (III). 41. Alloy according to any one of points 45-48, the specific surface area of ​​which is 0.2-10⁻⁵ m² / g, preferably 5-10⁻⁵ m² / g, measured according to DIN ISO 9277. 50. Alloy according to any one of points 45-49, wherein the alloy (II) comprises a thickness of 1-200 µm, preferably 1-60 µm. 51. Alloy according to any one of points 45-50, wherein the porous alloy (III) comprises a thickness of 1-300 µm, preferably 1-200 µm. 52.Alloy according to any one of points 45-51, wherein alloy (II) comprises Ni₂Al₃ and / or NiAl₃. 53. Method for producing an alloy according to any one of points 45-52, comprising the steps (A) providing a precursor according to any one of points 1-33 or 43, (B) treating the precursor at temperatures ≥ 600 °C, preferably 600-800 °C, for a duration preferably 1 min-300 min, more preferably 1-180 min, (C) treating the product obtained after step (B) in alkaline solution, preferably at elevated temperature, (D) optionally washing and drying the product obtained after step (C). 54. Method according to point 53, wherein the alkaline solution in step (C) is a 1-8 molar alkali hydroxide solution in water, and step (C) is preferably carried out at 20-80 °C. 55. Alloy obtainable by a process of points 53-54. 56. Use of the alloy according to one of points 45-52 or 55 as a catalyst and / or electrode, particularly in alkaline electrolysis.

Claims

1. Precursor comprising (i) a metallic substrate, in particular a nickel, iron or copper substrate and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 metallic particles, in particular aluminum, tin, silicon, iron and / or copper particles, and (ii)-3 at least one metal oxide, metal phosphide and / or metal sulfide, wherein the layered structure is arranged on the metallic substrate, and wherein the metallic substrate (i) is preferably different from component (ii)-2.

2. Precursor according to claim 1, comprising (i) a metallic nickel substrate and (ii) a layered structure comprising (ii)-1 at least one binder, (ii)-2 aluminium particles and (ii)-3 at least one metal oxide, preferably in a cubic, orthorhombic or tetragonal crystal structure, wherein the layered structure is arranged on the metallic nickel substrate.

3. Precursor according to any of the preceding claims, wherein the metallic substrate is in the form of a film, sheet, perforated sheet, fabric, expanded metal, foam, particle or plate and is preferably porous.

4. Precursor according to any of the preceding claims, wherein the binder is an organic binder, in particular an organic polymer, such as polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polypyrrole, or polyvinylpyrrolidone, preferably with a weight-average molecular weight of 1,000-40,000 g / mol.

5. Precursor according to any of the preceding claims, wherein the metal oxide is in a perovskite or spinel structure, and in particular has the formula ABO3, AB2O4 or A2B2O6, wherein A is at least one metal cation selected from Li, Na, K, Ca, Rb, Sr, Y, Ba, Ag, Bi, La, Ce, Pr, Nd, Sm and Gd cations, preferably La, Sr, Ba and Ca cations, and B is at least one metal cation selected from Mg, Sc, Ti. V-, Cr-, Mn-, Fe-, Co-, Ni-, Cu-, Zn-, Ga-, Al-, Ge-, Zr-, Nb-, Mo-, Ru-, Pd-, Cd-, In-, Sn-, Sb-, Ta-, and Ir-cations, preferably Cr-, Mn-, Fe-, Co-, Ni-, Ru-, Pd-ions, and / or the metal sulfide is in a stannite structure.

6. Precursor according to any of the preceding claims, wherein the layer structure comprises one (1) layer or two layers α and β.

7. Precursor according to any of the preceding claims, wherein the layer structure contains 1-50 wt.%, preferably 20-35 wt.% of component (ii)-2 based on the total weight of the layer structure and / or the layer structure contains 0.1-50 wt.%, preferably 0.1-10 wt.% of component (ii)-3 based on the total weight of the layer structure and / or the layer structure contains 0.1-20 wt.%, preferably 1-10 wt.% binder based on the total weight of the layer structure and / or the weight ratio of components (ii)-2:(ii)-3 is 100:1-9:1 in the layer structure.

8. Precursor according to claim 6, wherein layer α comprises at least one binder and component (ii)-3 and wherein layer β comprises at least one binder and component (ii)-2 and wherein layer α is preferably arranged on the metallic substrate and layer β is arranged on layer α.

9. A method for producing a precursor according to any one of the preceding claims, comprising the steps (a) providing a metallic substrate, in particular a metallic nickel substrate, (b) applying a suspension comprising a binder, solvent, preferably water or an organic solvent, e.g. isopropanol, acetone, dimethylformamide, butanol, ethanol or a mixture thereof, component (ii)-3 and optionally component (ii)-2, (c) removing the solvent, optionally at elevated temperature, to form a layer, (d) optionally applying a suspension comprising a binder, solvent and component (ii)-2 to the layer obtained after step (c), (e) optionally removing the solvent, optionally at elevated temperature, to form a layer β.

10. The method of claim 9, wherein in step (b) the suspension contains binder, solvent, component (ii)-2 and component (ii)-3, or wherein - if the suspension in step (b) contains binder, solvent, component (ii)-3 and no component (ii)-2, step (d) is essential and the suspension in step (d) contains binder, solvent and component (ii)-2.

11. Precursor obtainable by a method according to one of claims 9-10.

12. Use of a precursor according to any one of claims 1-8 or 11 for the production of a catalyst.

13. Alloy comprising (I) a metallic substrate, in particular a metallic nickel substrate, (II) at least one alloy comprising the metal according to (I), in particular a nickel-aluminium alloy, and (III) at least one porous alloy comprising the metal according to (I) in which at least one metal oxide, metal phosphide and / or metal sulfide is intercalated, wherein preferably the alloy (II) is arranged on the substrate (I) and the porous alloy (III) is arranged on the alloy (II).

14. A method for producing an alloy according to claim 13, comprising the steps (A) providing a precursor according to one of claims 1-8 or 11, (B) treating the precursor at temperatures ≥ 600 °C, preferably 600-800 °C for a duration preferably 1 min-300 min, more preferably 1-180 min, (C) treating the product obtained after step (B) in alkaline solution, preferably at elevated temperature, (D) optionally washing and drying the product obtained after step (C).

15. Alloy obtainable by a method according to claim 14.

16. Use of the alloy according to claim 13 or 15 as a catalyst and / or electrode, in particular in alkaline electrolysis.

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