Multi-element alloy catalyst, electrode containing rare earth elements and preparation and application thereof

Abstract

The present invention discloses a multi-component alloy catalyst containing rare earth elements, an electrode, and preparation and application thereof. The multi-component alloy catalyst containing rare earth elements includes iron powder, other metal powders and rare earth metal oxide powders, and the other metals are selected from one or more of nickel, chromium and manganese. The multi-component alloy catalyst containing rare earth elements is deposited on a metal substrate to obtain a multi-component alloy electrode containing rare earth elements, which can be used as an anode of an alkaline water electrolyzer for electrolyzing water to produce hydrogen. The alkaline water electrolyzer can show excellent activity and stability under high current density; and the multi-component alloy electrode containing rare earth elements can be directly activated in situ in the electrolyzer in a short time without the need for an additional step of long-term activation in a strong alkaline pool. The preparation method provided by the present invention is extremely simple and easy to operate, the source of raw materials is cheap and convenient, and it is suitable for large-scale assembly line production in workshops, thereby ensuring output and reducing costs, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of water electrolyzer electrodes, and in particular to a multi-component alloy catalyst containing rare earth elements, an electrode, and preparation and application thereof. Background Art

[0002] Water electrolysis technology coupled with renewable energy can produce green hydrogen without carbon emissions, and is considered an important way to decarbonize the energy sector. Typically, an alkaline water electrolyzer (AWE) consists of a cathode and an anode; and due to the half-reaction on the anode, the oxygen evolution reaction (OER) is considered to be the bottleneck reaction in the water electrolysis reaction. The OER performance of the anode can directly affect the overall working efficiency of the electrolyzer, and thus determine its operating cost. At present, AWE anodes are mainly made of nickel-aluminum (NiAl)-based OER catalysts (such as Raney Ni) deposited on metal substrates. Although the cost is low, the catalytic activity is still unsatisfactory under harsh industrial conditions (such as strong alkali, high temperature, strong oxidation, etc.), and long-term stability is difficult to maintain, resulting in high operating costs, making green hydrogen unable to compete with other hydrogen production methods based on traditional fossil energy. In addition, this type of electrode often requires additional pre-activation in a strong alkali, which further leads to more cumbersome steps and further increased costs ( Adv. Funct. Mater. 2023, 33 ,2303702). Based on the above difficulties, it is urgent to develop a new type of OER catalyst that is different from the traditional NiAl system. After being deposited on a metal substrate as an AWE anode, it has the advantages of high efficiency, durability, economy, easy large-scale preparation, and simple and direct operation.

[0003] At present, Fe metal-based catalysts have the following two advantages: 1) Fe has the lowest cost and the highest crustal abundance among all OER-active transition metals, which means that Fe metal materials have great advantages in cost and raw material sources for AWE anode catalysts (Ames National Laboratory, US Department of Energy (DOE), Understanding relative metal prices and availability: Combining physical and economic perspectives , 2021); 2) All OER-active transition metal-based catalysts actually only act as precatalysts in the alkaline OER process. Often, these catalyst materials are converted in situ into the corresponding (hydroxy) oxides as the real active phase. Compared with the common single transition metal (such as Ni, cobalt (Co), Mn) based phases, Fe-based (hydroxy) oxides have been proven to have the highest alkaline OER intrinsic catalytic activity ( J. Phys. Chem. Lett. 2015, 6 , 3737). However, the converted Fe-based (hydroxy) oxide phase has very poor corrosion resistance in alkaline OER because it is easily further oxidized to a higher valent phase (FeO4) in alkaline OER. 2- species, which are highly water soluble and often result in poor catalytic stability (GK Schweitzer, LL Pesterfield, The Aqueous Chemistry of the Elements , 2010; J. Phys. Chem. Lett. 2015, 6 , 3737). In addition, in OER electrochemistry, Fe-based (hydroxy) oxides exhibit extremely poor electrical conductivity and even insulating properties compared to other single transition metal-based phases ( J. Phys. Chem. Lett. 2015, 6 , 3737). On the other hand, the (hydroxy) oxide active species generated in situ during the OER process tend to exist in the form of agglomerated nanodomains, whereby the active sites are largely shielded and cannot contact the electrolyte to participate in the electrochemical reaction.

[0004] Therefore, although metallic Fe-based materials have great potential as alkaline OER catalysts and deposited as electrodes, they still need further modification and regulation to improve corrosion resistance, conductivity, and the limitation of insufficient exposure of active sites. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a multi-element alloy catalyst, electrode and preparation and application thereof containing rare earth elements (RE). The multi-element alloy catalyst containing RE is deposited on a metal substrate to obtain a multi-element alloy electrode containing RE, which can be used as an AWE anode for electrolysis of water to produce hydrogen.

[0006] The present invention is achieved through the following technical solutions:

[0007] A first aspect of the present invention provides a multi-component alloy catalyst containing rare earth elements, wherein the multi-component alloy catalyst containing rare earth elements comprises iron (Fe) powder, other metal powders and rare earth metal oxide powders, wherein the other metals are selected from one or more of nickel (Ni), chromium (Cr) and manganese (Mn).

[0008] Since RE tends to exist as a stable and insoluble oxide / hydroxide phase in alkaline OER scenarios, it will heterogeneously constrain and couple with the active transition metal-based (hydroxy)oxides generated in situ at the same time. Thanks to this, the dissolution of active transition metal atoms in OER electrochemistry is greatly alleviated; at the same time, the pseudo-periodic heterogeneous coupling with RE-based oxides / hydroxides causes the separation of active transition metal-based (hydroxy)oxide nanodomains, effectively avoiding the occurrence of agglomeration, thereby curbing the reduction in the exposure and accessibility of surface active transition metal sites. In addition, the formation of heterojunctions is believed to be beneficial for regulating the electronic structure of transition metal-based (hydroxy)oxide phases, improving the adsorption free energy and intrinsic OER activity of OER reaction intermediates. Therefore, the introduction of RE to regulate metallic Fe-based materials is expected to comprehensively improve their alkaline OER catalytic performance. In addition, Fe alloys doped with other cheap transition metals are selected to receive RE regulation because alloying is believed to be beneficial for improving various final physicochemical properties, such as conductivity, corrosion resistance, mechanical strength, etc.

[0009] The present invention forms a mixed phase through simple mechanical mixing, utilizes a small amount of cheap RE oxide powder raw material to modify the multi-component iron alloy (pre) catalyst, and significantly improves its performance.

[0010] Furthermore, the mass of the iron powder accounts for more than 50% of the sum of the mass of the iron powder and other metal powders.

[0011] Furthermore, when the other metals are Ni, Cr and Mn, the mass ratio of Fe, Ni, Cr and Mn is preferably (60~75):(5~15):(15~30):(0.1~5).

[0012] Furthermore, the rare earth metal oxide is selected from one or more of the oxides of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and yttrium (Y).

[0013] Furthermore, the mass of the rare earth metal in the rare earth metal oxide powder accounts for less than 30% of the mass of all metals in the multi-component alloy catalyst containing rare earth elements, preferably less than 5%, and less than 1% can also meet the requirements. Rare earth elements will be converted into insoluble oxide / hydroxide phases (without electrochemical activity, just acting as regulators) during the electrochemical process, thereby regulating and optimizing the metal-based (hydroxy) oxide phase generated by Fe (the active component responsible for the electrochemical reaction). When the amount of inactive regulator is too much, the active component will be reduced, resulting in poor performance.

[0014] The second aspect of the present invention provides a method for preparing the multi-component alloy catalyst containing rare earth elements described in the first aspect, comprising the following steps: mixing iron powder, other metal powders and rare earth metal oxide powder to obtain the multi-component alloy catalyst containing rare earth elements; the other metals are selected from one or more of nickel, chromium and manganese.

[0015] Furthermore, the mass of the iron powder accounts for more than 50% of the sum of the mass of the iron powder and other metal powders.

[0016] Furthermore, when the other metals are Ni, Cr and Mn, the mass ratio of Fe, Ni, Cr and Mn is (60~75):(5~15):(15~30):(0.1~5).

[0017] Furthermore, the rare earth metal oxide is one or more selected from the group consisting of oxides of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium.

[0018] Furthermore, the mass of the rare earth metal in the rare earth metal oxide powder accounts for less than 30% of the mass of all metals in the multi-component alloy catalyst containing rare earth elements, preferably less than 5%, and less than 1% can also meet the requirement.

[0019] In a specific embodiment, the preparation method of the multi-component alloy catalyst containing rare earth elements comprises the following steps:

[0020] (1) Mixing metallic iron with other metals to prepare a multi-element alloy powder;

[0021] (2) Mixing rare earth metal oxide powder and multi-component alloy powder to obtain the multi-component alloy catalyst containing rare earth elements.

[0022] Furthermore, in step (1), the method for preparing multi-element alloy powder comprises the following steps: placing a multi-element alloy obtained by mixing metallic iron with other metals in an evaporation furnace, evaporating the multi-element alloy into a gas phase, and obtaining the multi-element alloy powder after cooling.

[0023] In a specific embodiment, the method for preparing multi-component alloy powder includes the following steps: mixing iron metal ingots and other metal ingots to obtain a multi-component alloy; placing the multi-component alloy in an evaporation furnace through a fine feeder, heating it through plasma to evaporate the multi-component alloy into a gas phase, and cooling it into powder through an inert gas to obtain the multi-component alloy powder.

[0024] Furthermore, the inert gas is selected from one or more of argon, helium, krypton and xenon.

[0025] Furthermore, in step (1), the mixing time is 1 to 3 hours.

[0026] Furthermore, in step (1) and step (2), the mixing method is selected from one or more of grinding, ball milling, stirring, shaking and oscillation.

[0027] Furthermore, in step (2), the mixing time is 1 to 3 hours.

[0028] The third aspect of the present invention provides a multi-component alloy electrode containing rare earth elements, wherein the multi-component alloy electrode containing rare earth elements comprises a metal substrate and the multi-component alloy catalyst containing rare earth elements according to the first aspect deposited on the metal substrate.

[0029] Furthermore, the metal substrate is nickel foam or nickel mesh.

[0030] Since OER catalysts are usually deposited on Ni substrates (such as nickel foam or nickel mesh) to form AWE anodes, the surface of the Ni substrate will be in situ oxidized to oxyhydroxide (NiOOH) during the alkaline OER process, which will couple with FeOOH converted in situ from the deposited Fe-based compound (precatalyst) to form NiOOH / FeOOH. This heterogeneous species has been shown to have particularly enhanced electrocatalytic oxygen evolution activity. Therefore, the AWE anode obtained by depositing a small amount of RE-regulated metal Fe-based catalyst on a Ni-based metal substrate will have greatly optimized catalytic activity and stability.

[0031] The present invention utilizes the hydrochemical properties of RE, that is, it will not precipitate under the oxygen evolution reaction environment of the water electrolysis anode, but tends to exist as a stable oxide / hydroxide insoluble phase, thereby coupling and constraining the Fe / Ni / Mn (hydroxy) oxide phase derived from the multi-element alloy (widely regarded as the real catalytic active substance, in this system, mainly Fe-based) formed in situ under alkaline OER, thereby achieving a regulatory effect.

[0032] The present invention has considerable system innovation, and develops a Fe alloy catalyst that is cheaper, simple to synthesize, and can be mass-produced. It can be deposited on different Ni-based substrates on a large scale and with high applicability to prepare a new generation of electrodes. During the anode OER process, it can quickly form an active phase regulated by RE oxide / hydroxide in situ, which is mainly Fe-based (hydroxy) oxide; it is particularly noteworthy that the Ni substrate is inevitably oxidized to (quasi) NiOOH substances at the same time, which couples with Fe-based (hydroxy) oxides, thereby substantially improving the intrinsic oxygen evolution performance of the electrode. Based on this, the present invention specifically solves the problem that the NiAl electrode cannot be converted into a highly active phase in situ during the OER electrochemical process (due to the easy solubility of Al in the alkaline OER scenario, the main active phase is the Ni-based (hydroxy) oxide formed in situ), and needs to be activated for a long time in a strong base (to promote the full precipitation of Al).

[0033] The fourth aspect of the present invention provides a method for preparing a multi-component alloy electrode containing rare earth elements, comprising the following steps: using a plasma thermal spraying method or an ultrasonic cold spraying method to deposit the multi-component alloy catalyst containing rare earth elements described in the first aspect on a metal substrate to obtain the multi-component alloy electrode containing rare earth elements.

[0034] Furthermore, the deposition amount of the multi-component alloy catalyst containing rare earth elements on the metal substrate is 1-100 mg·cm -2 .

[0035] Furthermore, the plasma thermal spraying method does not require any additional bonding agents or additives, and the deposition area can be controlled from 0.001 to 5 m 2 The shape of the deposition surface can also be adjusted, such as round, rectangular, etc.

[0036] Furthermore, ultrasonic cold spraying requires the addition of 5-10 wt% Nafion connector with a volume fraction of 3%-5% to enhance the firmness of the deposited alloy; the deposition area is controllable from 0.001 to 5 m 2 The shape of the deposition surface can also be adjusted, such as round, rectangular, etc.

[0037] The fifth aspect of the present invention provides an alkaline water electrolyzer, comprising an anode, a cathode and an electrolyte, wherein the anode is the multi-component alloy electrode containing rare earth elements as described in the fourth aspect.

[0038] Furthermore, the cathode may be nickel-molybdenum foam.

[0039] Furthermore, the electrolyte may be a KOH aqueous solution.

[0040] The multi-element alloy electrode containing rare earth elements provided by the present invention is equipped as an anode in AWE, and AWE can show excellent activity and stability under high current density; and the electrode can be directly activated in situ in the electrolytic cell in a short time without the need for an additional long-term activation step in a strong alkaline cell.

[0041] The present invention also protects the use of the multi-component alloy catalyst containing rare earth elements, the multi-component alloy electrode containing rare earth elements or the alkaline water electrolyzer in the production of hydrogen by electrolysis of water.

[0042] The multi-component alloy electrode containing rare earth elements provided by the present invention is also expected to be applied to the fields of hydrogen fuel cells, direct alcohol fuel cells, etc., and has considerable ductility and applicability.

[0043] Beneficial effects of the present invention:

[0044] 1. The present invention uses a small amount of one or more rare earth element oxides, and through mechanical mixing, regulates the multi-element Fe alloy doped with other elements to obtain an OER catalyst. On this basis, a simple large-scale spraying method (plasma thermal spraying or ultrasonic cold spraying) is adopted to deposit the prepared catalyst on a metal substrate (such as nickel foam, nickel mesh, etc.) to obtain an electrode.

[0045] 2. When the multi-element alloy electrode containing rare earth elements provided by the present invention is used as the anode of an alkaline water electrolyzer, the water chemical properties of the rare earth elements are utilized to convert them in situ into stable and insoluble oxide / hydroxide phases, thereby stabilizing and deeply coupling and regulating the transition metal (mainly Fe)-based (hydroxy) oxide active phase generated in situ at the same time, thereby achieving the effect of improving the catalytic performance.

[0046] 3. The preparation method of the multi-element alloy electrode containing rare earth elements provided by the present invention is extremely simple and easy to operate, the raw material source is cheap and convenient, and it is suitable for large-scale assembly line production in the workshop, thereby ensuring the output and reducing the cost; and the multi-element alloy electrode containing rare earth elements can change its size, shape, and the loading amount of OER catalyst according to the anode target parameters of the actual alkaline water electrolyzer equipped. Therefore, it has considerable production and application capabilities.

[0047] 4. When the multi-element alloy electrode containing rare earth elements provided by the present invention is used as the anode of an alkaline water electrolyzer, it can be directly activated in the electrolyzer under industrial conditions (6 M KOH aqueous electrolyte and 85°C operating temperature), and the pre-activation process can be completed within 3 minutes, avoiding the additional step of long-term activation treatment in strong alkali required for conventional nickel-aluminum (NiAl)-based electrodes.

[0048] 5. The alkaline water electrolyzer provided by the present invention can operate at 5000 A·m under industrial conditions of 6 M KOH aqueous electrolyte and operating temperature of 85°C with a cell voltage of less than 1.83 V. -2 The industrial current density is much higher than that of similar electrolyzers, such as alkaline water electrolyzers containing multi-element alloy anodes not modified with rare earth element oxides and common NiAl (such as Raney Ni) based anodes on the market.

[0049] 6. The present invention breaks through the shackles of the electrode composition of the current industrial alkaline water electrolyzer being limited to the NiAl system. In addition, the multi-element alloy electrode regulated by a small amount of rare earth elements developed by the present invention is simple and direct to implement, and the cost is greatly reduced. It is very suitable for application in industrial alkaline water electrolyzers, and can directly promote the cost reduction and scale upgrade of green hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1This is a physical picture of the La-multi-alloy electrode of Example 1.

[0051] Figure 2 1 and 2 are XRD patterns of the La-multinary alloy electrode and the La-free multinary alloy electrode of Example 1.

[0052] Figure 3 This is the SEM image of the La-multi-alloy electrode of Example 1.

[0053] Figure 4 The SEM-EDX element mapping diagram of the La-multi-alloy electrode of Example 1; wherein (a) is the SEM image, (b) is the La element mapping diagram, (c) is the Fe element mapping diagram, (d) is the Ni element mapping diagram, (e) is the Cr element mapping diagram, and (f) is the Mn element mapping diagram.

[0054] Figure 5 The SEM-EDX spectrum of the La-multinary alloy electrode of Example 1 and the corresponding element mass fractions.

[0055] Figure 6 The in-situ pre-activation (time-tank voltage) curves of the La-multi-alloy electrode of Example 1, the Ce-multi-alloy electrode of Example 4, the multi-alloy electrode-electrodeposition of Comparative Example 1, the multi-alloy electrode and the commercial NiAl electrode as AWE anodes.

[0056] Figure 7 The linear sweep voltammetry (LSV) curves of water electrolysis of AWEs including the La-multi-alloy electrode of Example 1, the Ce-multi-alloy electrode of Example 4, the multi-alloy electrode-electrodeposition of Comparative Example 1, the multi-alloy electrode and the commercial NiAl electrode. DETAILED DESCRIPTION

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0058] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0059] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified. Example 1

[0060] A multi-component alloy electrode containing lanthanum (La) element (La-multi-component alloy), wherein the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing La element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0061] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, commercially available lanthanum oxide (La2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on La element, that is, the mass of La in La2O3 powder accounts for 0.3% of the mass of all metals in the multi-component alloy catalyst containing La element) to obtain a multi-component alloy (La-multi-component alloy) catalyst containing La element. Finally, the obtained La-multi-component alloy catalyst was deposited on a Ni mesh substrate by plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular.

[0062] Figure 1 This is a physical picture of the La-multi-element alloy electrode of Example 1. Figure 1 It can be seen that the La-multi-alloy catalyst powder is evenly sprayed on the circular Ni mesh substrate.

[0063] Figure 2 The XRD patterns of the La-multinary alloy electrode and the multinary alloy electrode without La in Example 1 are shown in Figure 2. Figure 2 It can be seen that the diffraction characteristic peaks belonging to the Ni mesh substrate and the multi-component alloy can be distinguished in the XRD of the two electrodes, and no relevant characteristic peaks appear in the La-multi-component alloy due to the low La2O3 content.

[0064] Figure 3 This is a scanning electron microscope (SEM) image of the La-multi-element alloy electrode of Example 1. Figure 3 It can be seen that the La-multi-alloy is densely and firmly deposited on the Ni mesh substrate, presenting a micron-sphere stacking morphology.

[0065] Figure 4 This is a cold field emission scanning electron microscope & energy dispersive spectrometer (SEM-EDX) element mapping diagram of the La-multi-alloy electrode of Example 1. Figure 4It can be seen that La element (b), Fe element (c), Ni element (d), Cr element (e), and Mn element (f) are evenly distributed on the electrode, further proving the uniform deposition of La-multinary alloy on the Ni mesh substrate.

[0066] Figure 5 The SEM-EDX spectrum of the La-multinary alloy electrode of Example 1 and the corresponding element mass fractions. Figure 5 It was confirmed that this La-multi-component alloy was mainly an Fe alloy doped with Ni, Cr, and Mn, which was regulated by trace amounts (<1% mass fraction) of La (i.e., La2O3); it also proved the successful preparation of La-multi-component alloy electrodes. Example 2

[0067] A multi-component alloy electrode containing lanthanum (La) element (La-multi-component alloy), wherein the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing La element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0068] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the mixed alloy into a gas phase, and then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available lanthanum oxide (La2O3) powder was mixed with the prepared multi-component alloy powder at a mass fraction of 0.3% (based on La element) for 2 h to obtain a multi-component alloy (La-multi-component alloy) catalyst containing La element. Finally, the obtained La-multi-component alloy catalyst was deposited on a foamed Ni substrate by ultrasonic cold spraying. During the spraying, a 5 wt% Nafion connector with a volume fraction of 3% was added to enhance the firmness of the deposited alloy, and the deposition amount was about 5 mg cm -2 , with an area of ​​approximately 0.003 m 2 , the shape of the deposition surface is circular. Example 3

[0069] A multi-component alloy electrode containing lanthanum (La) element (La-multi-component alloy), wherein the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing La element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0070] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available lanthanum oxide (La2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 30% (based on La element) to obtain a multi-component alloy (La-multi-component alloy) catalyst containing La element. Finally, the obtained La-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 4

[0071] A multi-component alloy electrode containing cerium (Ce) element (Ce-multi-component alloy), the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing Ce element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0072] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, commercially available cerium dioxide (CeO2) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on Ce element) to obtain a multi-component alloy (Ce-multi-component alloy) catalyst containing Ce element. Finally, the obtained Ce-multi-component alloy catalyst was deposited on a Ni mesh substrate by plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 5

[0073] A multi-component alloy electrode containing praseodymium (Pr) element (Pr-multi-component alloy), the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing Pr element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0074] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, commercially available praseodymium oxide (Pr2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Pr element) to obtain a multi-component alloy (Pr-multi-component alloy) catalyst containing the Pr element. Finally, the obtained Pr-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 6

[0075] A multi-element alloy (Nd-multi-element alloy) electrode containing neodymium (Nd) element, wherein the multi-element alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-element alloy catalyst containing Nd element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0076] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available neodymium oxide (Nd2O3) powder was mixed with the prepared multi-component alloy powder at a mass fraction of 0.3% (based on the Nd element) for 2 h to obtain a multi-component alloy (Nd-multi-component alloy) catalyst containing the Nd element. Finally, the obtained Nd-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 7

[0077] A multi-component alloy electrode containing samarium (Sm) element (Sm-multi-component alloy), the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing Sm element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0078] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, commercially available samarium oxide (Sm2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Sm element) to obtain a multi-component alloy (Sm-multi-component alloy) catalyst containing the Sm element. Finally, the obtained Sm-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 8

[0079] A multi-element alloy (Eu-multi-element alloy) electrode containing europium (Eu) element, wherein the multi-element alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-element alloy catalyst containing Eu element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0080] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-element alloy powder. Then, commercially available europium oxide (Eu2O3) powder was mixed with the prepared multi-element alloy powder for 2 h at a mass fraction of 0.3% (based on Eu element) to obtain a multi-element alloy (Eu-multi-element alloy) catalyst containing Eu element. Finally, the obtained Eu-multi-element alloy catalyst was deposited on a Ni mesh substrate by plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 9

[0081] A multi-component alloy (Gd-multi-component alloy) electrode containing a gadolinium (Gd) element, wherein the multi-component alloy electrode containing a rare earth element comprises a Ni mesh substrate and a multi-component alloy catalyst containing a Gd element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0082] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available gadolinium oxide (Gd2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Gd element) to obtain a multi-component alloy (Gd-multi-component alloy) catalyst containing the Gd element. Finally, the obtained Gd-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 10

[0083] A multi-component alloy (Pm-multi-component alloy) electrode containing a promethium (Pm) element, wherein the multi-component alloy electrode containing a rare earth element comprises a Ni mesh substrate and a multi-component alloy catalyst containing the Pm element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0084] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available promethium oxide (Pm2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Pm element) to obtain a multi-component alloy (Pm-multi-component alloy) catalyst containing the Pm element. Finally, the obtained Pm-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Embodiment 11

[0085] A multi-component alloy electrode containing erbium (Er) element (Er-multi-component alloy), the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing Er element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0086] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, commercially available erbium oxide (Er2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Er element) to obtain a multi-component alloy (Er-multi-component alloy) catalyst containing the Er element. Finally, the obtained Er-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 12

[0087] A multi-element alloy (Yb-multi-element alloy) electrode containing ytterbium (Yb) element, wherein the multi-element alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-element alloy catalyst containing Yb element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0088] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-element alloy powder. Then, the commercially available ytterbium oxide (Yb2O3) powder was mixed with the prepared multi-element alloy powder for 2 h at a mass fraction of 0.3% (based on the Yb element) to obtain a multi-element alloy (Yb-multi-element alloy) catalyst containing the Yb element. Finally, the obtained Yb-multi-element alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 13

[0089] A multi-element alloy electrode containing lutetium (Lu) element (Lu-multi-element alloy), the multi-element alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-element alloy catalyst containing Lu element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0090] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-element alloy powder. Then, the commercially available lutetium oxide (Lu2O3) powder was mixed with the prepared multi-element alloy powder for 2 h at a mass fraction of 0.3% (based on Lu element) to obtain a multi-element alloy (Lu-multi-element alloy) catalyst containing Lu element. Finally, the obtained Lu-multi-element alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Embodiment 14

[0091] A multi-component alloy (Y-multi-component alloy) electrode containing yttrium (Y) element, wherein the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing the Y element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0092] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h in a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available yttrium oxide (Y2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Y element) to obtain a multi-component alloy (Y-multi-component alloy) catalyst containing the Y element. Finally, the obtained Y-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Embodiment 15

[0093] A multi-component alloy electrode containing dysprosium (Dy) element (Dy-multi-component alloy), the multi-component alloy electrode containing rare earth elements comprises a Ni mesh substrate and a multi-component alloy catalyst containing Dy element deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0094] Using a high-temperature solid phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available dysprosium oxide (Dy2O3) powder was mixed with the prepared multi-component alloy powder for 2 h at a mass fraction of 0.3% (based on the Dy element) to obtain a multi-component alloy (Dy-multi-component alloy) catalyst containing the Dy element. Finally, the obtained Dy-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Example 16

[0095] A multi-component alloy (Ho-multi-component alloy) electrode containing a holmium (Ho) element, wherein the multi-component alloy electrode containing a rare earth element comprises a Ni mesh substrate and a multi-component alloy catalyst containing the Ho element deposited on the Ni mesh substrate, and a preparation method comprises the following steps:

[0096] Using a high-temperature solid-phase method, Fe, Ni, Cr and Mn metal ingots were mixed by ball milling for 2 h at a mass ratio of 66.8:9:23.3:0.6. Then, they were added to an evaporation furnace through a fine feeder and heated by plasma to evaporate the alloy mixture into a gas phase, which was then cooled into powder by argon gas to obtain a multi-component alloy powder. Then, the commercially available holmium oxide (Ho2O3) powder was mixed with the prepared multi-component alloy powder at a mass fraction of 0.3% (based on the Ho element) for 2 h to obtain a multi-component alloy (Ho-multi-component alloy) catalyst containing the Ho element. Finally, the obtained Ho-multi-component alloy catalyst was deposited on a Ni mesh substrate using plasma thermal spraying, with a deposition amount of about 60 mg cm -2 , with an area of ​​approximately 0.05 m 2 , the shape of the deposition surface is circular. Comparative Example 1

[0097] A multi-element alloy electrode (multi-element alloy electrode-electrodeposition) prepared by an electrodeposition method, wherein the multi-element alloy electrode comprises a Ni mesh substrate and a multi-element alloy catalyst deposited on the Ni mesh substrate, and the preparation method comprises the following steps:

[0098] The nitrate containing Fe, Ni, Cr, Mn and La was dissolved in water in the ratio of Fe:Ni:Cr:Mn:La with an atomic mass ratio of 66.8:9:23.3:0.6:0.3 to form a salt solution. The above salt solution was used as the electrolyte, and a three-electrode system with a platinum sheet as the counter electrode, a calomel electrode as the reference electrode and a Ni mesh as the working electrode was used to deposit the multi-electrode alloy catalyst on the Ni mesh substrate by chronoamperometry. The deposition amount was about 60 mg cm -2 , with an area of ​​approximately 4 cm 2 , the shape of the deposition surface is square.

[0099] Test Example 1

[0100] The multi-element alloy electrodes containing rare earth elements of Examples 1 to 16, the multi-element alloy electrode-electrodeposition of Comparative Example 1, the multi-element alloy electrode (without rare earth elements) and the commercial NiAl electrode were tested for water electrolysis in AWE. The test method is as follows:

[0101] AWE includes an anode, a cathode and an electrolyte. The anode is a multi-element alloy electrode containing rare earth elements, the cathode is blank nickel-molybdenum foam, the electrolyte is a 6 M KOH aqueous solution, and the operating temperature is 85 °C.

[0102] Figure 6 The graph is a graph of in-situ pre-activation (time-tank voltage) of the La-multi-alloy electrode of Example 1, the Ce-multi-alloy electrode of Example 4, the multi-alloy electrode-electrodeposition of Comparative Example 1, the multi-alloy electrode (without rare earth elements) and the commercial NiAl electrode as AWE anodes. Figure 6 It can be seen that the activation time of La-multi-alloy electrode and Ce-multi-alloy electrode in AWE is only <3 min, and the cell voltage tends to be stable, indicating that the in-situ pre-activation process is completed, avoiding the step of traditional NiAl-based AWE anode requiring extra long activation time in strong alkali.

[0103] Figure 7 The linear sweep voltammetry (LSV) curves of water electrolysis of AWEs including the La-multi-alloy electrode of Example 1, the Ce-multi-alloy electrode of Example 4, the multi-alloy electrode-electrodeposition of Comparative Example 1, the multi-alloy electrode (without rare earth elements) and the commercial NiAl electrode. Figure 7 It can be confirmed that the AWE of the La-multi-element alloy electrode of Example 1 reaches up to 5000 A·m -2The industrial current density only requires <1.83 V cell voltage, and the Ce-multi-alloy electrode has similar performance, both of which are significantly better than the multi-alloy electrode without RE and the same AWE with the mainstream commercial NiAl-based anode sold on the market. In addition, the multi-alloy electrode containing rare earth elements prepared by the high-temperature solid phase method of the present invention has similar element types and proportions as the comparative example 1, but the multi-alloy electrode prepared by the electrodeposition method has significantly better performance.

[0104] The performance of the multi-component alloy electrodes containing rare earth elements in Examples 2 to 3 and Examples 5 to 16 is better than the performance of the multi-component alloy electrodes not containing rare earth elements under the same conditions.

[0105] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An alkaline water electrolyzer comprising an anode, a cathode and an electrolyte, characterized in that: The anode is a multi-component alloy electrode containing rare earth elements, and the multi-component alloy electrode containing rare earth elements comprises a metal substrate and a multi-component alloy catalyst containing rare earth elements deposited on the metal substrate; the metal substrate is nickel foam or nickel mesh; The multi-component alloy catalyst containing rare earth elements comprises iron powder, other metal powders and rare earth metal oxide powders, and the other metals are selected from one or more of nickel, chromium and manganese.

2. The alkaline water electrolyzer according to claim 1, characterized in that: The mass of the iron powder accounts for more than 50% of the sum of the mass of the iron powder and other metal powders.

3. The alkaline water electrolyzer according to claim 1, characterized in that: The rare earth metal oxide is selected from one or more of the oxides of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium.

4. The alkaline water electrolyzer according to claim 1, characterized in that: The mass of the rare earth metal in the rare earth metal oxide powder accounts for less than 30% of the mass of all metals in the multi-component alloy catalyst containing rare earth elements.

5. The alkaline water electrolyzer according to claim 1, characterized in that: The preparation method of the multi-component alloy catalyst containing rare earth elements comprises the following steps: mixing iron powder, other metal powders and rare earth metal oxide powders to obtain the multi-component alloy catalyst containing rare earth elements; the other metals are selected from one or more of nickel, chromium and manganese.

6. The alkaline water electrolyzer according to claim 1, characterized in that: The method for preparing the multi-component alloy electrode containing rare earth elements comprises the following steps: depositing the multi-component alloy catalyst containing rare earth elements on a metal substrate by plasma thermal spraying or ultrasonic cold spraying to obtain the multi-component alloy electrode containing rare earth elements.

7. The alkaline water electrolyzer according to claim 1, characterized in that: The deposition amount of the multi-component alloy catalyst containing rare earth elements on the metal substrate is 1-100 mg•cm -2 .

8. Use of the alkaline water electrolyzer according to claim 1 in producing hydrogen by electrolyzing water.

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