Nickel-based active cathode and preparation method thereof

Abstract

The invention relates to a nickel-based active cathode and a preparation method thereof, the nickel-based active cathode comprises a conductive substrate of a nickel base material, the conductive substrate is made of a nickel wire-based pull net or a nickel wire net, the outer surface of the conductive substrate is coated with a sintered metal oxide layer, and the outer surface of the sintered metal oxide layer is coated with a metal oxide catalyst layer; the metal oxide catalyst layer is composed of an oxide of ruthenium or an oxide of iridium and an oxide of lanthanide, the thickness of the metal oxide catalyst layer is 2-10 [mu] m, and the metal oxide coating comprises 75-85% by mole of ruthenium or iridium and 5-10% by mole of lanthanide in terms of metal components. The molar percentage of the lanthanide elements is 15%-25%. According to the nickel-based active cathode and the preparation method thereof, corrosion of a coating solution to a nickel base material can be effectively avoided, the service life of an electrode is remarkably prolonged, the reverse current resisting capacity of the electrode is improved, damage of the reverse current to a cathode surface net is restrained, and the hydrogen evolution potential of the cathode is reduced.

Description

Technical Field

[0001] The invention relates to the field of sodium hydroxide preparation, in particular to a nickel-based active cathode and a preparation method thereof. Background Art

[0002] The inventors have discovered through experiments for the first time that an important reason for the oxidative dissolution of the cathode substrate is that the ruthenium coating solution is mostly prepared using hydrochloric acid, nitric acid, ruthenium nitrate and the like as precursors. Since the coating solution contains a large amount of strong acid radicals such as hydrochloric acid and nitric acid, these hydrochloric acid and nitric acid salts will corrode and damage the substrate, causing a large amount of corroded nickel ions to appear in the coating solution during coating. These nickel ions that have separated from the cathode substrate will precipitate into the cathode catalyst layer when the active layer is formed. The nickel element precipitated into the cathode catalyst layer may cause the active catalyst layer on the surface of the cathode substrate to be separated from the active catalyst layer of the cathode during electrolysis, thereby reducing the service life of the electrode.

[0003] Since the hydrochloric acid and nitric acid salts in the coating solution are corrosive to the cathode nickel substrate, the nickel substrate on the cathode substrate will dissolve into the coating solution, resulting in a generally high nickel content in the hydrochloric acid cathode coating. After the ion membrane electrolyzer has been running for a period of time, there will be a certain amount of Ni contamination on the surface of the ion membrane, which will also have an adverse effect on the membrane efficiency.

[0004] In addition, most membrane-gap electrolyzers currently use ruthenium oxide coatings. The reverse current will cause the cathode in the cathode chamber to be oxidized by the reverse current. The cathode coating will turn into hydroxide and lose its activity. The cathode substrate will be oxidized and dissolved. The oxidation and dissolution of the cathode substrate will further cause the coating to separate from the substrate and fall off, causing the cathode to reduce or lose its activity, thereby reducing the service life of the cathode. Summary of the invention

[0005] The present invention aims to provide a nickel-based active cathode and a preparation method thereof which can effectively avoid corrosion of the nickel substrate by the coating liquid, significantly prolong the service life of the electrode, improve the ability of the electrode to resist reverse current, inhibit the damage of the reverse current to the cathode surface mesh, reduce the hydrogen evolution potential of the cathode, and reduce the power consumption.

[0006] The nickel-based active cathode of the present invention comprises a conductive substrate of a nickel substrate, the conductive substrate is made of a nickel wire-based stretched mesh or a nickel wire mesh, the outer surface of the conductive substrate is covered with a burnt metal oxide layer, and the outer surface of the burnt oxide layer is covered with a metal oxide catalyst layer;

[0007] The metal oxide catalyst layer is composed of ruthenium oxide or iridium oxide and lanthanide oxide, the thickness of the metal oxide catalyst layer is 2 μm-10 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 75%-85%, and the molar percentage of lanthanide is 15%-25% according to the metal components;

[0008] The nickel-based active cathode is prepared by the following steps:

[0009] A. preparing a nickel-based conductive substrate by using a nickel-based wire mesh or a nickel-based wire screen, cleaning the conductive substrate, removing surface dirt of the conductive substrate, and roughening the surface of the conductive substrate;

[0010] B. sintering the conductive substrate at 200°C-350°C for 10 minutes-50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0011] Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside;

[0012] C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution;

[0013] D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate;

[0014] Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0015] E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

[0016] Preferably, the thickness of the metal oxide catalyst layer is 4 μm-8 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 78%-82%, and the molar percentage of lanthanide is 17%-23% according to the metal components;

[0017] In the step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0018] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 78% to 82% by mole of the ruthenium element or the iridium element and 17% to 23% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 100 to 140 g / L, to obtain a coating solution;

[0019] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 120° C. to 280° C. in an air atmosphere for 15 minutes to 45 minutes to obtain a first heat-treated conductive substrate;

[0020] Then, the first heat-treated conductive substrate is heated to 350° C.-550° C. for 15 minutes-45 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0021] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4 μm-8 μm, thus obtaining a nickel-based active cathode.

[0022] Preferably, the thickness of the metal oxide catalyst layer is 5 μm-7 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 79%-81%, and the molar percentage of lanthanide is 18%-22% according to the metal components;

[0023] In the step B, the conductive substrate is subjected to a sintering treatment at 250° C. to 300° C. for 25 minutes to 35 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0024] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 79% to 81% by mole of the ruthenium element or the iridium element and 18% to 22% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 110 to 130 g / L, to obtain a coating solution;

[0025] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 150° C.-250° C. in an air atmosphere for 20 minutes-40 minutes to obtain a first heat-treated conductive substrate;

[0026] Then, the first heat-treated conductive substrate is heated to 400° C.-500° C. for 20 minutes-40 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0027] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5 μm-7 μm, thus obtaining a nickel-based active cathode.

[0028] The method for preparing the nickel-based active cathode of the present invention comprises the following steps:

[0029] A. preparing a nickel-based conductive substrate by using a nickel-based wire mesh or a nickel-based wire mesh, cleaning the conductive substrate, removing surface dirt of the conductive substrate, and roughening the surface of the conductive substrate;

[0030] B. sintering the conductive substrate at 200°C-350°C for 10 minutes-50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0031] Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside;

[0032] C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution;

[0033] D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate;

[0034] Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0035] E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

[0036] Preferably, in the step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes, and a sintered metal oxide layer is formed on the outer surface of the conductive substrate;

[0037] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 78% to 82% by mole of the ruthenium element or the iridium element and 17% to 23% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 100 to 140 g / L, to obtain a coating solution;

[0038] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 120° C. to 280° C. in an air atmosphere for 15 minutes to 45 minutes to obtain a first heat-treated conductive substrate;

[0039] Then, the first heat-treated conductive substrate is heated to 350° C.-550° C. for 15 minutes-45 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0040] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4 μm-8 μm, thus obtaining a nickel-based active cathode.

[0041] Preferably, the thickness of the metal oxide catalyst layer is 5 μm-7 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 79%-81%, and the molar percentage of lanthanide is 18%-22% according to the metal components;

[0042] In the step B, the conductive substrate is subjected to a sintering treatment at 250° C. to 300° C. for 25 minutes to 35 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0043] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 79% to 81% by mole of the ruthenium element or the iridium element and 18% to 22% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 110 to 130 g / L, to obtain a coating solution;

[0044] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 150° C.-250° C. in an air atmosphere for 20 minutes-40 minutes to obtain a first heat-treated conductive substrate;

[0045] Then, the first heat-treated conductive substrate is heated to 400° C.-500° C. for 20 minutes-40 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0046] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5 μm-7 μm, thus obtaining a nickel-based active cathode.

[0047] Use the nickel-based active cathode described in any one of claims 1 to 3.

[0048] An electrolysis device using the nickel-based active cathode according to any one of claims 1 to 3.

[0049] A nickel-based active cathode prepared by the preparation method according to any one of claims 4 to 6.

[0050] An electrolysis device using a nickel-based active cathode prepared by the preparation method according to any one of claims 4 to 6.

[0051] Compared with the prior art, the nickel-based active cathode and the preparation method thereof of the present invention have the following beneficial effects:

[0052] 1. Firing the nickel substrate at 200-350°C to form an oxide layer on the surface of the conductive substrate and ensuring that the firing temperature is within the controlled range can reduce the hydrogen evolution potential of the nickel-based active cathode.

[0053] Second, the metal oxide catalyst layer has high stability. As a metal compound coating liquid coated on a nickel-based conductive substrate, the metal oxide catalyst layer formed by the ruthenium chloride solution may contain a small amount of chloride, which may cause the metal oxide catalyst layer to deteriorate due to oxidation when exposed to air. Moreover, ruthenium chloride is reduced to metallic ruthenium when the solution is thermally decomposed in a reducing atmosphere of hydrogen. Metallic ruthenium has a high overvoltage, and the solution peels off from the substrate, resulting in poor stability of the nickel-based active cathode. The acetic acid-based coating liquid of the present invention is completely thermally decomposed, and there is no residual chloride in the metal oxide catalyst layer, which enhances the stability of the nickel-based active cathode.

[0054] 3. Compared with the hydrochloric acid coating liquid, the acetic acid coating liquid of the present invention has larger acetate ligands around the ruthenium particles. Such ligands help to better disperse the ruthenium particles in the active catalytic layer. When ruthenium acetate is used as a precursor, ruthenium acetate forms a chelate with the ruthenium particle clusters through the carboxyl group, which prevents the further agglomeration of the ruthenium particle clusters, thereby reducing the particle size of the ruthenium particle clusters. The active cathode has fewer lattice defects and is easy to form a larger specific surface area, which is beneficial to the enhancement of the adsorption and desorption of hydrogen. The acetic acid solvent in the acetic acid coating liquid can make the active components of the ruthenium particles evenly dispersed, thereby improving the catalytic activity.

[0055] Fourth, the ruthenium coating using hydrochloric acid, nitric acid, ruthenium acylate nitrate, etc. as precursors contains a large amount of strong acid salts in the coating solution, which is corrosive to the substrate to a certain extent, resulting in a large amount of nickel ions in the coating solution during coating, which is easily converted into a nickel layer and precipitated into the cathode catalyst layer during the formation of the active layer. The precipitated nickel can cause the cathode metal oxide catalyst layer to peel off during the electrolysis process, thereby reducing the service life of the electrode. The acetic acid coating solution of the present invention has very low corrosiveness to the substrate, the nickel content in the metal oxide catalyst layer is very low, and less nickel is precipitated, thereby preventing the metal oxide catalyst layer of the cathode of the nickel-based active cathode from peeling off during the electrolysis process, and increasing the service life of the nickel-based active cathode.

[0056] Fifth, the cathode coating is usually produced by roller coating. In the process of making hydrochloric acid cathode, since hydrochloric acid and hydrochloride have a corrosive effect on the cathode nickel substrate, the Ni substrate dissolves into the coating liquid during the roller coating process, resulting in a generally high nickel content in the hydrochloric acid cathode coating. After the ion membrane electrolyzer has been running for a period of time, there is a certain amount of Ni contamination on the surface of the ion membrane, which has a certain impact on the membrane efficiency. In the process of roller coating of the acetic acid coating of the present invention, since the coating liquid has little corrosiveness to the substrate, the nickel substrate is not easily dissolved into the coating liquid, the nickel ion content in the coating liquid is extremely low, and the nickel content in the metal oxide catalyst layer is extremely small. In the ion membrane electrolyzer, the Ni contamination on the surface of the ion membrane is reduced.

[0057] 6. When hydrochloric acid coating solution is thermally decomposed, chlorine gas is generated, and when nitric acid salt solution is thermally decomposed, nitrogen dioxide and nitric oxide gas are generated, both of which are harmful gases. During the implementation of the present invention, acetate is less irritating to personnel than hydrochloric acid, and less corrosive than nitric acid. Its volatile products do not contain chlorides and nitrogen oxides, and are more environmentally friendly.

[0058] In summary, the nickel-based active cathode of the present invention, because the catalyst layer is made of acetate metal as the coating liquid, avoids the problem that the coating liquid contains a large amount of nickel ions during coating, which is unknown to the predecessors. Since no nickel element is precipitated into the cathode catalyst layer when the active layer is formed, the active catalyst layer of the cathode is more solid during the electrolysis process, thereby greatly improving the service life of the electrode, and also improving the electrode's ability to resist reverse current. At the same time, before coating the active layer, an empty burning treatment is performed at a certain temperature to form an oxide layer on the surface of the substrate, which can not only protect the substrate surface to a certain extent and prevent the corrosion of the coating liquid to the substrate, but also further make the nickel-based active cathode have excellent catalytic activity for hydrogen evolution reaction, effectively reduce the hydrogen evolution potential of the electrode, and improve the pollution effect on the ion membrane. Therefore, the nickel-based active cathode of the present invention and its preparation method have the characteristics of effectively avoiding the corrosion of the coating liquid to the nickel substrate, significantly extending the service life of the electrode, improving the ability of the electrode to resist reverse current, inhibiting the damage caused by the reverse current to the cathode surface mesh, reducing the hydrogen evolution potential of the cathode, and reducing power consumption.

[0059] Other details and features of the nickel-based active cathode and its preparation method of the present invention will become clear by reading the embodiments described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A comparison diagram of hydrogen evolution potential between various embodiments and various comparative examples of the nickel-based active cathode of the present invention;

[0061] Figure 2 It is a comparison diagram of the reverse current resistance between various embodiments and various comparative examples of the nickel-based active cathode of the present invention;

[0062] Figure 3 The diagram is a hydrogen evolution potential diagram of an acetic acid electrode of the conductor substrate of the nickel-based active cathode of the present invention when calcined at different temperatures. DETAILED DESCRIPTION

[0063] The nickel-based active cathode of the present invention comprises a conductive substrate of a nickel substrate, the conductive substrate is made of a nickel wire-based stretched mesh or a nickel wire mesh, the outer surface of the conductive substrate is covered with a burnt metal oxide layer, and the outer surface of the burnt oxide layer is covered with a metal oxide catalyst layer;

[0064] The metal oxide catalyst layer is composed of ruthenium oxide or iridium oxide and lanthanide oxide, the thickness of the metal oxide catalyst layer is 2 μm-10 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 75%-85%, and the molar percentage of lanthanide is 15%-25% according to the metal components;

[0065] The nickel-based active cathode is prepared by the following steps:

[0066] A. preparing a nickel-based conductive substrate by using a nickel-based wire mesh or a nickel-based wire screen, cleaning the conductive substrate, removing surface dirt of the conductive substrate, and roughening the surface of the conductive substrate;

[0067] B. sintering the conductive substrate at 200°C-350°C for 10 minutes-50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0068] Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside;

[0069] C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution;

[0070] D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate;

[0071] Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0072] E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

[0073] As a further improvement of the present invention, the thickness of the metal oxide catalyst layer is 4 μm-8 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 78%-82%, and the molar percentage of lanthanide is 17%-23% according to the metal components;

[0074] In the step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0075] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 78% to 82% by mole of the ruthenium element or the iridium element and 17% to 23% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 100 to 140 g / L, to obtain a coating solution;

[0076] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 120° C. to 280° C. in an air atmosphere for 15 minutes to 45 minutes to obtain a first heat-treated conductive substrate;

[0077] Then, the first heat-treated conductive substrate is heated to 350° C.-550° C. for 15 minutes-45 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0078] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4 μm-8 μm, thus obtaining a nickel-based active cathode.

[0079] As a further improvement of the present invention, the thickness of the metal oxide catalyst layer is 5 μm-7 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 79%-81%, and the molar percentage of lanthanide is 18%-22% according to the metal components;

[0080] In the step B, the conductive substrate is subjected to a sintering treatment at 250° C. to 300° C. for 25 minutes to 35 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0081] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 79% to 81% by mole of the ruthenium element or the iridium element and 18% to 22% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 110 to 130 g / L, to obtain a coating solution;

[0082] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 150° C.-250° C. in an air atmosphere for 20 minutes-40 minutes to obtain a first heat-treated conductive substrate;

[0083] Then, the first heat-treated conductive substrate is heated to 400° C.-500° C. for 20 minutes-40 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0084] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5 μm-7 μm, thus obtaining a nickel-based active cathode.

[0085] The method for preparing the nickel-based active cathode of the present invention comprises the following steps:

[0086] A. preparing a nickel-based conductive substrate by using a nickel-based wire mesh or a nickel-based wire screen, cleaning the conductive substrate, removing surface dirt of the conductive substrate, and roughening the surface of the conductive substrate;

[0087] B. sintering the conductive substrate at 200°C-350°C for 10 minutes-50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0088] Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside;

[0089] C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution;

[0090] D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate;

[0091] Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0092] E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

[0093] As a further improvement of the present invention, in the above step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes, and a sintered metal oxide layer is formed on the outer surface of the conductive substrate;

[0094] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 78% to 82% by mole of the ruthenium element or the iridium element and 17% to 23% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 100 to 140 g / L, to obtain a coating solution;

[0095] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 120° C. to 280° C. in an air atmosphere for 15 minutes to 45 minutes to obtain a first heat-treated conductive substrate;

[0096] Then, the first heat-treated conductive substrate is heated to 350° C.-550° C. for 15 minutes-45 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0097] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4 μm-8 μm, thus obtaining a nickel-based active cathode.

[0098] As a further improvement of the present invention, the thickness of the metal oxide catalyst layer is 5 μm-7 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 79%-81%, and the molar percentage of lanthanide is 18%-22% according to the metal components;

[0099] In the step B, the conductive substrate is subjected to a sintering treatment at 250° C. to 300° C. for 25 minutes to 35 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0100] In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 79% to 81% by mole of the ruthenium element or the iridium element and 18% to 22% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 110 to 130 g / L, to obtain a coating solution;

[0101] In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 150° C.-250° C. in an air atmosphere for 20 minutes-40 minutes to obtain a first heat-treated conductive substrate;

[0102] Then, the first heat-treated conductive substrate is heated to 400° C.-500° C. for 20 minutes-40 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate;

[0103] In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5 μm-7 μm, thus obtaining the nickel-based active cathode of the present invention.

[0104] The present invention also includes the use of the nickel-based active cathode described in any one of claims 1 to 3.

[0105] The present invention also includes an electrolysis device using the nickel-based active cathode described in any one of claims 1 to 3.

[0106] The present invention also includes a nickel-based active cathode prepared by the preparation method described in any one of claims 4 to 6.

[0107] The present invention also includes an electrolysis device using a nickel-based active cathode prepared by the preparation method described in any one of claims 4 to 6.

[0108] In the present invention, all "firing" refers to producing a layer of metal oxide on the surface of the conductor substrate through sintering. Firing is a thermal oxidation process.

[0109] The lanthanide elements are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

[0110] The object of the present invention is to provide a stable cathode having a certain ability to resist reverse current and a long service life.

[0111] The nickel-based active cathode of the present invention adopts acetate metal as a coating liquid to prepare a catalyst layer, thereby avoiding the problem that a large amount of nickel ions are contained in the coating liquid during coating, which is unknown to the prior art. Since no nickel element is precipitated into the cathode catalyst layer when the active layer is formed, the active catalyst layer of the cathode is more solid during the electrolysis process, thereby greatly improving the service life of the electrode and also improving the reverse current resistance of the electrode. At the same time, before coating the active layer, an empty burning treatment is performed at a certain temperature, which can improve the conductivity of the substrate, so that the nickel-based active cathode has excellent catalytic activity for hydrogen evolution reaction, effectively reduces the hydrogen evolution potential of the electrode, and improves the pollution effect on the ion membrane.

[0112] Example 1.

[0113] The preparation method of the nickel-based active cathode of the present invention is as follows:

[0114] ⑴Pretreatment of conductive substrate

[0115] First, use 250-320 mesh white corundum sand to sandblast the 35 mesh nickel-based screen woven with φ0.18mm nickel wire as a conductive substrate, then put clean water and cleaning agent into the ultrasonic cleaner, heat it to 50°C, and then put the nickel-based screen in. The screen must be completely immersed in clean water and ultrasonically cleaned for 4 hours to remove the sand remaining on the surface of the screen to obtain the cleaned conductive substrate.

[0116] (2) The conductive substrate is sintered at 300° C. for 40 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0117] ⑶ This embodiment contains ruthenium acetate and cerium acetate, wherein the concentration of ruthenium acetate is 90g / L, the molar percentage of ruthenium is 85%, and the molar percentage of cerium is 15%.

[0118] The ruthenium acetate solution is mixed with the cerium acetate and stirred with a magnetic stirrer until the cerium acetate is completely dissolved to form a uniform mixed solution.

[0119] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh that has been fired, first fired in an air atmosphere at a low temperature of 250°C for 20 minutes, and then continued to be fired in an air atmosphere at a high temperature of 500°C for 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 8 times to obtain the nickel-based active cathode of the present invention.

[0120] Example 2

[0121] The preparation method of the nickel-based active cathode of the present invention is as follows:

[0122] First, use 300-mesh white corundum sand to sandblast the 32-mesh nickel-based screen woven with φ0.20mm nickel wire as a conductive substrate, and then put clean water and cleaning agent into the ultrasonic cleaner, raise the temperature to 40°C, and then put the nickel-based screen in. The screen must be completely immersed in clean water and ultrasonically cleaned for 3 hours to remove the sand remaining on the surface of the screen to obtain the cleaned conductive substrate.

[0123] (2) The conductive substrate is sintered at 350° C. for 10 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0124] ⑶ This embodiment contains ruthenium acetate and cerium acetate, wherein the concentration of ruthenium acetate is 150g / L, the molar percentage of ruthenium is 75%, and the molar percentage of cerium is 25%.

[0125] The ruthenium acetate solution is mixed with the cerium acetate and stirred with a magnetic stirrer until the cerium acetate is completely dissolved to form a uniform mixed solution.

[0126] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh, first fired in an air atmosphere at a low temperature of 150°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 460°C for another 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 10 times to obtain the nickel-based active cathode of the present invention.

[0127] Example 3

[0128] ⑴Pretreatment of conductive substrate

[0129] The pretreatment of the substrate is the same as in Example 1.

[0130] (2) The conductive substrate is sintered at 200° C. for 50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0131] ⑶ This embodiment contains ruthenium acetate and praseodymium acetate, wherein the concentration of ruthenium acetate is 90g / L, the molar percentage of ruthenium is 88%, and the molar percentage of praseodymium is 12%.

[0132] The ruthenium acetate solution is mixed with praseodymium acetate and stirred with a magnetic stirrer until the praseodymium acetate is completely dissolved to form a uniform mixed solution.

[0133] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh, first fired in an air atmosphere at a low temperature of 150°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 10 times to obtain the nickel-based active cathode of the present invention.

[0134] Example 4

[0135] ⑴Pretreatment of conductive substrate

[0136] The pretreatment of the substrate is the same as in Example 1.

[0137] (2) The conductive substrate is sintered at 250° C. for 15 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate;

[0138] ⑶ This embodiment contains ruthenium acetate and praseodymium acetate, wherein the concentration of ruthenium acetate is 90g / L, the molar percentage of ruthenium is 85%, and the molar percentage of praseodymium is 15%.

[0139] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh, first fired in an air atmosphere at a low temperature of 150°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 10 times to obtain the nickel-based active cathode of the present invention.

[0140] Example 5

[0141] ⑴Pretreatment of conductive substrate

[0142] The pretreatment of the substrate is the same as in Example 1.

[0143] (2) The pretreated substrate was calcined at 300°C for 30 minutes.

[0144] ⑶ Preparation of precious metal oxide catalysts

[0145] This embodiment contains ruthenium acetate, cerium acetate and praseodymium acetate, wherein the concentration of ruthenium acetate is 90 g / L, the molar percentage of ruthenium in the metal salt is 80%, the molar percentage of cerium is 10%, and the molar percentage of praseodymium is 10%.

[0146] The ruthenium acetate solution, cerium acetate and praseodymium acetate are mixed and stirred with a magnetic stirrer until the cerium acetate and praseodymium acetate are completely dissolved to form a uniform mixed solution.

[0147] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh, first fired in an air atmosphere at a low temperature of 250°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 525°C for another 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 8 times to obtain the nickel-based active cathode of the present invention.

[0148] Example 6

[0149] ⑴Pretreatment of conductive substrate

[0150] The pretreatment of the substrate is the same as in Example 1.

[0151] (2) The pretreated substrate was calcined at 300°C for 30 minutes.

[0152] ⑶ Preparation of precious metal oxide catalysts

[0153] This embodiment contains ruthenium acetate, cerium acetate and praseodymium acetate, wherein the concentration of ruthenium acetate is 90 g / L, the molar percentage of ruthenium in the metal salt is 80%, the molar percentage of cerium is 15%, and the molar percentage of praseodymium is 5%.

[0154] The ruthenium acetate solution, cerium acetate and praseodymium acetate are mixed and stirred with a magnetic stirrer until the cerium acetate and praseodymium acetate are completely dissolved to form a uniform mixed solution.

[0155] The prepared acetate metal salt solution is evenly coated on the nickel wire mesh, first fired in an air atmosphere at a low temperature of 300°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 550°C for another 30 minutes to thermally decompose the acetate metal salt. This operation is repeated 8 times to obtain the nickel-based active cathode of the present invention.

[0156] Comparative Example 1

[0157] The nickel-based active cathode of this comparative example and its preparation method are as follows:

[0158] ⑴Pretreatment of substrate

[0159] The pretreatment of the substrate is the same as in Example 1.

[0160] ⑵ Preparation of metal oxide catalysts

[0161] This comparative example contains ruthenium nitrate and cerium nitrate, wherein the concentration of ruthenium nitrate is 100 g / L, and the molar percentage of the metal salt is ruthenium:cerium=85%:15%.

[0162] The ruthenium nitrate solution and the cerium nitrate are mixed and stirred with a magnetic stirrer until the cerium nitrate is completely dissolved to form a uniform mixed solution.

[0163] The prepared nitrate metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 200°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes for thermal decomposition treatment, and this operation is repeated 12 times.

[0164] Comparative Example 2

[0165] The nickel-based active cathode of this comparative example and its preparation method are as follows:

[0166] ⑴Pretreatment of conductive substrate

[0167] The pretreatment of the substrate is the same as in Example 1.

[0168] (2) Preparation of metal oxide catalyst intermediate layer

[0169] This comparative example contains ruthenium chloride and cerium chloride, wherein the concentration of ruthenium chloride is 90 g / L, and the molar percentage of the metal salt is ruthenium:cerium=80%:20%.

[0170] The ruthenium chloride solution and the cerium chloride are mixed and stirred with a magnetic stirrer until the cerium chloride is completely dissolved to form a uniform mixed solution.

[0171] The prepared hydrochloric acid metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 150°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 550°C for another 30 minutes for thermal decomposition treatment. This operation is repeated 12 times to obtain a metal oxide catalyst intermediate layer with a certain thickness.

[0172] Comparative Example 3

[0173] The nickel-based active cathode of this comparative example and its preparation method are as follows:

[0174] ⑶Pretreatment of substrate

[0175] The pretreatment of the substrate is the same as in Example 1.

[0176] ⑷ Preparation of metal oxide catalysts

[0177] This comparative example contains ruthenium nitrate and praseodymium nitrate, wherein the concentration of ruthenium nitrate is 100 g / L, and the molar percentage of the metal salt is ruthenium:cerium=85%:15%.

[0178] Place the ruthenium nitrate solution on a magnetic stirrer with a heater and stir for 10 minutes, then add the praseodymium nitrate solution and continue stirring for 10 minutes, then heat and stir with a heating magnetic stirrer. When the solution temperature reaches 80°C, keep it warm for 100 minutes. Turn off the heater of the heating magnetic stirrer and cool it to room temperature while stirring with the heating magnetic stirrer.

[0179] The prepared nitrate metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 200°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes for thermal decomposition treatment. This operation is repeated 12 times to obtain a metal oxide catalyst intermediate layer with a certain thickness.

[0180] Comparative Example 4

[0181] The nickel-based active cathode of this comparative example and its preparation method are as follows:

[0182] ⑴Pretreatment of conductive substrate

[0183] The pretreatment of the substrate is the same as in Example 1.

[0184] ⑷ Preparation of metal oxide catalyst intermediate layer

[0185] This comparative example contains ruthenium chloride and praseodymium chloride, wherein the concentration of ruthenium chloride is 90 g / L, and the molar percentage of the metal salt is ruthenium:cerium=80%:20%.

[0186] Place the ruthenium chloride solution on a magnetic stirrer with a heater and stir for 10 minutes, then add the praseodymium chloride solution and continue stirring for 10 minutes, then heat and stir with a heating magnetic stirrer. When the solution temperature reaches 80°C, keep it warm for 100 minutes. Turn off the heater of the heating magnetic stirrer and cool it to room temperature while stirring with a heating magnetic stirrer.

[0187] The prepared hydrochloric acid metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 150°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 450°C for another 30 minutes for thermal decomposition treatment. This operation is repeated 12 times to obtain a metal oxide catalyst intermediate layer with a certain thickness.

[0188] Comparative Example 5

[0189] The nickel-based active cathode of this comparative example and its preparation method are as follows:

[0190] ⑴Pretreatment of substrate

[0191] The pretreatment of the substrate is the same as in Example 1.

[0192] (2) Preparation of metal oxide catalyst layer

[0193] This comparative example contains ruthenium nitrate, cerium nitrate and praseodymium nitrate, wherein the concentration of ruthenium nitrate is 100 g / L, and the molar percentage of the metal salts is ruthenium:cerium:praseodymium=75%:15%:10%.

[0194] Place the ruthenium nitrate solution on a magnetic stirrer with a heater and stir for 10 minutes. Then add cerium nitrate and praseodymium nitrate and continue stirring for 10 minutes. Then heat and stir with a heating magnetic stirrer. When the solution temperature reaches 80°C, keep it warm for 100 minutes. Turn off the heater of the heating magnetic stirrer and cool it to room temperature while stirring with a heating magnetic stirrer.

[0195] The prepared nitrate metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 200°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes for thermal decomposition treatment. This operation is repeated 12 times to obtain a metal oxide catalyst layer with a certain thickness.

[0196] Comparative Example 6

[0197] ⑴Pretreatment of conductive substrate

[0198] The pretreatment of the substrate is the same as in Example 1

[0199] (2) The pretreated substrate was calcined at 500°C for 30 minutes.

[0200] ⑶ Preparation of precious metal oxide catalysts

[0201] Same as Example 1

[0202] Comparative Example 7:

[0203] ⑴Pretreatment of conductive substrate

[0204] Same as comparative example 1

[0205] (2) The pretreated substrate was calcined at 300°C for 40 minutes.

[0206] ⑶ Preparation of precious metal oxide catalysts

[0207] The comparative example contains ruthenium nitrate and cerium nitrate, wherein the concentration of ruthenium nitrate is 100 g / L, and the molar percentage of the metal salt is ruthenium:cerium=85%:15%. The ruthenium nitrate solution and the cerium nitrate are mixed and stirred with a magnetic stirrer until the cerium nitrate is completely dissolved to form a uniform mixed solution.

[0208] (3.1) Bottom catalytic layer: The prepared nitrate metal salt solution is evenly coated on the conductive substrate, first fired in an air atmosphere at a low temperature of 200°C for 30 minutes, and then fired in an air atmosphere at a high temperature of 500°C for another 30 minutes for thermal decomposition treatment, and this operation is repeated 12 times.

[0209] (3.2) Surface catalytic layer: platinum nitrate solution, in which the concentration of platinum is 50g / L. The platinum nitrate metal salt solution is evenly coated on the metal oxide catalyst intermediate layer of the conductive substrate and fired in an air atmosphere at a low temperature of 200°C for 20 minutes. Then, it is further fired in an air atmosphere at a high temperature of 500°C for 20 minutes for heat treatment to obtain a Pt-containing catalytic layer.

[0210] 1. Hydrogen evolution potential detection: In the electrolyte of 32% sodium hydroxide solution, the hydrogen evolution potential detection was carried out at 90°C. The results are as follows:

[0211] Table 1

[0212]

[0213]

[0214] 2. Enhanced reverse current test: by electrolyzing in a sodium hydroxide solution with a mass fraction of 32%, multiple enhanced reverse current acceleration tests are carried out continuously to determine the coating residue. Figure 2 This is a comparison chart of the Ru residue in the coating for reverse current resistance, which shows that the composite coating electrode in the present invention has a stronger ability to resist reverse current. The electrolyte is a sodium hydroxide solution with a mass fraction of 32%, and electrolysis is carried out at 90°C under 8KA / m2 conditions. After 48 hours, reverse electrolysis is carried out at 100A / m2 for 2 hours every 4 hours, for a total of 10 times.

[0215] Table 2

[0216] Residual amount of enhanced reverse current coating % Example 1 75.5 Example 2 78.2 Example 3 70.4 Example 4 72.1 Example 5 77.6 Example 6 78.0 Comparative Example 1 44.8 Comparative Example 2 26.2 Comparative Example 3 51.8 Comparative Example 4 25.4 Comparative Example 5 39.5 Comparative Example 6 48.2 Comparative Example 7 73.3

[0217] 3. Since the acetic acid coating liquid of the present invention has low corrosiveness to the substrate, the nickel content in the coating liquid after coating is completed is shown in Table 3

[0218] Table 3

[0219] Hydrochloric acid coating liquid Nitric acid based coating fluid Acetic acid coating liquid Nickel content detection of coating liquid Ni(ppm) Ni(ppm) Ni(ppm) After coating is completed 254 128 45

[0220] It can be seen from Table 1 that the cathode hydrogen evolution potential in each embodiment is relatively stable and relatively low, the potential values ​​in Comparative Examples 1-5 fluctuate greatly, and the potential of Comparative Example 6 is higher than that of Example 1. Although the potential values ​​of Comparative Examples 2 / 4 / 5 are low, the coating residue is very low in the anti-reverse electrical strengthening experiment shown in Table 2; it can be seen from Table 2 that the results of the anti-reverse electrical strengthening experiment show that the coating residue of the electrode of the present invention after reverse electricity can reach the level of non-acetic acid electrode containing the precious metal Pt surface catalytic layer. Comparative Example 7 can be seen from Table 3 that the nickel content in the acetic acid coating solution of the present invention is the lowest.

[0221] See also Figure 1 , Figure 1 The figure is a comparison diagram of hydrogen evolution potential between various embodiments of the nickel-based active cathode of the present invention and various comparative examples; the figure shows that the hydrogen evolution potential of the embodiments of the present invention is lower than that of the comparative examples as a whole, indicating that the electrochemical performance thereof is better.

[0222] See also Figure 2 , Figure 2 It is a comparison diagram of the reverse current resistance between various embodiments of the nickel-based active cathode of the present invention and various comparative examples; the figure shows that the reverse current resistance of the embodiments of the present invention is much higher than that of the comparative examples.

[0223] See also Figure 3 , Figure 3 The hydrogen evolution potential diagram of the acetic acid electrode of the nickel-based active cathode conductor substrate of the present invention is calcined at different temperatures. It can be seen that the hydrogen evolution potential of the acetic acid electrode of the present invention in which the substrate is calcined at a temperature of 200°C-350°C is lower than that of the acetic acid electrode of the present invention in which the substrate is calcined at a temperature outside this calcination temperature range.

[0224] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineers and technicians in the field should all fall within the protection scope of the claims of the present invention.

Claims

1. Nickel-based active cathode, Features A conductive substrate comprising a nickel substrate, the conductive substrate is made of a nickel wire-based stretched mesh or a nickel wire mesh, the outer surface of the conductive substrate is covered with a burnt metal oxide layer, and the outer surface of the burnt oxide layer is covered with a metal oxide catalyst layer; The metal oxide catalyst layer is composed of ruthenium oxide or iridium oxide and lanthanide oxide, the thickness of the metal oxide catalyst layer is 2 μm-10 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 75%-85%, and the molar percentage of lanthanide is 15%-25% according to the metal components; The nickel-based active cathode is prepared by the following steps: A. preparing a nickel-based conductive substrate by using a nickel-based wire mesh or a nickel-based wire screen, cleaning the conductive substrate, removing surface dirt of the conductive substrate, and roughening the surface of the conductive substrate; B. sintering the conductive substrate at 200°C-350°C for 10 minutes-50 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate; Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside; C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution; D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate; Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate; E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

2. The nickel-based active cathode according to claim 1, Features The thickness of the metal oxide catalyst layer is 4 μm-8 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 78%-82%, and the molar percentage of lanthanide is 17%-23% according to the metal components; In the step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate; In step C, ruthenium acetate or iridium acetate obtained in step B is mixed with a soluble acetate solution of a lanthanide element in a ratio that the molar percentage of ruthenium element or iridium element is 78% - 82%, and the molar percentage of lanthanide element is 17% - 23%. The concentration of ruthenium element or iridium element in the mixed solution is 100 - 140 g / L to obtain a coating solution. In step D, the coating solution obtained in step C is coated on the conductive substrate treated in step B, and the conductive substrate is heated to 120°C - 280°C in an air atmosphere for 15 minutes - 45 minutes to obtain a first heat-treated conductive substrate. Then, the first heat-treated conductive substrate is heated to 350°C - 550°C for 15 minutes - 45 minutes to obtain a conductive substrate with a metal oxide catalyst layer coated on the outer surface of the conductive substrate. In step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4μm - 8μm, thus obtaining a nickel-based active cathode.

3. The nickel-based active cathode according to claim 2, characterized in that the thickness of the metal oxide catalyst layer is 5μm - 7μm. Calculated by metal components in the metal oxide coating, the molar percentage of ruthenium element or iridium element is 79% - 81%, and the molar percentage of lanthanide element is 18% - 22%. In step B, the conductive substrate is subjected to a firing treatment at 250°C - 300°C for 25 minutes - 35 minutes to form a fired metal oxide layer on the outer surface of the conductive substrate. In step C, ruthenium acetate or iridium acetate obtained in step B is mixed with a soluble acetate solution of a lanthanide element in a ratio that the molar percentage of ruthenium element or iridium element is 79% - 81%, and the molar percentage of lanthanide element is 18% - 22%. The concentration of ruthenium element or iridium element in the mixed solution is 110 - 130 g / L to obtain a coating solution. In step D, the coating solution obtained in step C is coated on the conductive substrate treated in step B, and the conductive substrate is heated to 150°C - 250°C in an air atmosphere for 20 minutes - 40 minutes to obtain a first heat-treated conductive substrate. Then, the first heat-treated conductive substrate is heated to 400°C - 500°C for 20 minutes - 40 minutes to obtain a conductive substrate with a metal oxide catalyst layer coated on the outer surface of the conductive substrate. In step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5μm - 7μm, thus obtaining a nickel-based active cathode.

4. A method for preparing a nickel-based active cathode, characterized in that it includes the following steps: A. A conductive substrate of a nickel-based material is prepared by using a nickel wire-based expanded metal or a nickel wire mesh. The conductive substrate is cleaned to remove surface contaminants and roughen the surface of the conductive substrate. B. The conductive substrate is subjected to a firing treatment at 200°C - 350°C for 10 minutes - 50 minutes to form a fired metal oxide layer on the outer surface of the conductive substrate. Prepare a soluble acetate of a lanthanide element, prepare ruthenium acetate or iridium acetate, dissolve the ruthenium acetate or iridium acetate in water, add the soluble acetate of the lanthanide element, stir evenly, obtain a soluble acetate solution of ruthenium acetate or iridium acetate and lanthanide element, and set aside; C. Mixing the ruthenium acetate or iridium acetate obtained in step B with a soluble acetate solution of lanthanide elements in a ratio of 75% to 85% by mole of ruthenium or iridium and 15% to 25% by mole of lanthanide elements, wherein the concentration of ruthenium or iridium in the mixed solution is 90 to 150 g / L, to obtain a coating solution; D. coating the coating solution obtained in step C onto the conductive substrate treated in step B, heating the conductive substrate to 100° C.-300° C. in an air atmosphere for 10 minutes-50 minutes to obtain a first heat-treated conductive substrate; Then, the first heat-treated conductive substrate is heated to 300° C. to 600° C. for 10 minutes to 50 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate; E. Repeat step D for multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 2 μm-10 μm, thereby obtaining a nickel-based active cathode.

5. The method for preparing the nickel-based active cathode according to claim 4, Features In the step B, the conductive substrate is subjected to a sintering treatment at 220° C. to 330° C. for 20 minutes to 40 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate; In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 78% to 82% by mole of the ruthenium element or the iridium element and 17% to 23% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 100 to 140 g / L, to obtain a coating solution; In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 120° C. to 280° C. in an air atmosphere for 15 minutes to 45 minutes to obtain a first heat-treated conductive substrate; Then, the first heat-treated conductive substrate is heated to 350° C.-550° C. for 15 minutes-45 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate; In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 4 μm-8 μm, thus obtaining a nickel-based active cathode.

6. The method for preparing the nickel-based active cathode according to claim 5, Features The thickness of the metal oxide catalyst layer is 5 μm-7 μm, and the molar percentage of ruthenium or iridium in the metal oxide coating is 79%-81%, and the molar percentage of lanthanide is 18%-22% according to the metal components; In the step B, the conductive substrate is subjected to a sintering treatment at 250° C. to 300° C. for 25 minutes to 35 minutes to form a sintered metal oxide layer on the outer surface of the conductive substrate; In the step C, the ruthenium acetate or iridium acetate obtained in the step B is mixed with a soluble acetate solution of a lanthanide element in a ratio of 79% to 81% by mole of the ruthenium element or the iridium element and 18% to 22% by mole of the lanthanide element, and the concentration of the ruthenium element or the iridium element in the mixed solution is 110 to 130 g / L, to obtain a coating solution; In the step D, the coating solution obtained in the step C is coated on the conductive substrate treated in the step B, and the conductive substrate is heated to 150° C.-250° C. in an air atmosphere for 20 minutes-40 minutes to obtain a first heat-treated conductive substrate; Then, the first heat-treated conductive substrate is heated to 400° C.-500° C. for 20 minutes-40 minutes to obtain a conductive substrate having a metal oxide catalyst layer coated on the outer surface of the conductive substrate; In the step E, step D is repeated multiple times until the thickness of the metal oxide catalyst layer on the surface of the conductive substrate is 5 μm-7 μm, thus obtaining a nickel-based active cathode.

7. Use of the nickel-based active cathode according to any one of claims 1 to 3.

8. An electrolysis device using the nickel-based active cathode according to any one of claims 1 to 3.

9. A nickel-based active cathode prepared by the preparation method according to any one of claims 4 to 6.

10. An electrolysis device using a nickel-based active cathode prepared by the preparation method according to any one of claims 4 to 6.

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