Multi-element alloy porous electrode and preparation method and application thereof
By doping rare earth metals and Al in the electrolytic water hydrogen production catalyst, multi-alloy porous electrodes are prepared, which solves the problem of difficult to take into account both the activity and stability of the catalyst, and achieves efficient hydrogen production and long-term stability, and has broad industrial application prospects.
Patent Information
- Application Number
- CN202510099768.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-04-11
AI Technical Summary
The existing electrolytic hydrogen production catalysts have problems that they are difficult to take into account both the activity and the stability. Especially under high-temperature and concentrated alkali conditions, highly active metal elements such as Co, Mo, Fe are prone to metal dissolution, affecting long-term stable performance.
By doping rare earth metal and Al, multi-alloy porous electrodes are prepared, and three-dimensional continuous pores and extremely small rare earth metal alloy phases are formed using rare earth metals to improve catalytic activity, and the precipitation of transition metals is suppressed through rare earth metals to enhance electrode stability.
While improving catalytic activity and stability, it inhibits the dissolution loss of active elements and extends the life of the catalyst. It is suitable for industrial applications of electrolyzed hydrogen production.
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Figure CN119800406A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of hydrogen evolution material preparation, and mainly to a multi-element alloy porous electrode and a preparation method and application thereof. Background Art
[0002] Hydrogen (H2), as a green and renewable energy, is regarded as a promising energy carrier due to its high energy density and environmental protection characteristics. At present, hydrogen energy has become a strategic technology for the energy technology revolution and industrial development of major countries in the world. Support policies of various countries are constantly being introduced and improved, industrial technology innovation is constantly iterating and upgrading, and emerging business models and application scenarios are constantly emerging, which has created an important opportunity window for accelerating the development of the hydrogen energy industry. The market scale of hydrogen production by water electrolysis has increased significantly under the incentive of policies. According to research reports, the scale of hydrogen production by renewable energy will exceed 100 million tons by 2060. As a mature commercial hydrogen production technology, the alkaline water electrolysis hydrogen production system will become an important way to produce hydrogen on a large scale.
[0003] Currently, the commercial electrolytic water hydrogen production electrode catalyst uses Raney nickel, which is a nickel-aluminum alloy, which can achieve long-term stable operation for hydrogen production. However, the Raney nickel catalyst has low activity and high overpotential, which makes it difficult to meet the next step of fluctuating operating conditions. Therefore, the development of high-activity, long-term stable and low-cost electrodes is the main task of the current development of electrolytic water.
[0004] Alloy electrode catalyst materials are favored by scientific research workstations because of their good mechanical properties, high stability, and easy adjustment. However, pure alloy materials have low activity, and highly active metal elements such as Co, Mo, Fe, etc. have metal dissolution under high temperature and concentrated alkali conditions, resulting in the loss of active substances and affecting long-term stability. Therefore, it is urgent to develop effective strategies to improve the activity of alloy materials in electrolyzing water to produce hydrogen while inhibiting the dissolution of active elements. Therefore, the existing technology still needs to be improved and developed. Summary of the invention
[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a multi-element alloy porous electrode and a preparation method and application thereof, aiming to solve the problem that it is difficult to balance the activity or stability of the existing hydrogen production catalysts.
[0006] The technical solution of this application is as follows: In a first aspect, the present application provides a method for preparing a multi-element alloy porous electrode, which comprises the following steps: preparing a multi-element alloy precursor; Activating the multi-component alloy precursor to obtain the multi-component alloy porous electrode; The multi-element alloy precursor is doped with rare earth metal and Al.
[0007] The preparation method provided by the present application helps to prepare a multi-element alloy porous electrode with three-dimensional continuous pores by doping with rare earth metals, which can improve the catalytic activity. At the same time, the prepared multi-element alloy porous electrode retains the remaining rare earth metals after preparation for further self-sacrificial strategy, which can form a very small rare earth metal alloy phase, greatly promoting hydrogen production activity. At the same time, rare earth metals are also beneficial to inhibit the precipitation of other transition metals that may be added under high temperature and concentrated alkali conditions, thereby improving electrode stability.
[0008] Furthermore, the raw material of the multi-element alloy precursor is a multi-element alloy metal powder, which includes the following components calculated by mass percentage: Sacrificial metal 3wt% -25wt%, rare earth metal 0.5wt% -20wt%, the remainder is main metal; The sacrificial metal is Al; The rare earth metal is one or more of La, Ce, Sm, Nb, Pr, Pm, Er, and Gd; The main metal is one or more of Ni, Co, Fe, Mo, Mn, Ti and Cr.
[0009] Furthermore, the step of preparing the multi-element alloy precursor comprises: Weigh the multi-element alloy metal powder according to proportion, put it into a vacuum arc melting furnace for melting, and obtain an alloy ingot precursor after cooling; The alloy ingot precursor is cut into electrode sheet sizes.
[0010] Furthermore, the smelting current is 150-220A and the smelting time is 1-5min; The melting was repeated at least three times under argon atmosphere.
[0011] Furthermore, the step of activating the multi-element alloy precursor comprises: The multi-element alloy precursor is placed in an alkaline solution for heating and activation to remove rare earth oxides and Al.
[0012] Further, the concentration of the alkaline solution is 3 mol / L-8 mol / L, the heating temperature is 40°C-160°C, and the activation time is 1h-144h; The alkali in the alkaline solution is one or both of potassium hydroxide and sodium hydroxide.
[0013] In a second aspect, the present application provides a multi-component alloy porous electrode, wherein the electrode is prepared by the method for preparing the multi-component alloy porous electrode as described in the first aspect.
[0014] Furthermore, the multi-element alloy porous electrode comprises a continuous pore structure, and the pore diameter of the continuous pore structure is 0.5 μm-8 μm.
[0015] Furthermore, the multi-element alloy porous electrode includes a rare earth metal alloy phase.
[0016] In a third aspect, the present application provides an application of the multi-component alloy porous electrode as described in the second aspect, wherein the multi-component alloy porous electrode is applied to produce hydrogen by electrolysis of water.
[0017] Beneficial effects: Through the preparation method provided by the present application, by doping rare earth metals, it is helpful to prepare a multi-element alloy porous electrode with three-dimensional continuous pores, which can improve the catalytic activity. At the same time, the prepared multi-element alloy porous electrode retains the remaining rare earth metal after preparation for further self-sacrificial strategy, which can form a very small rare earth metal alloy phase, greatly promoting hydrogen production activity. At the same time, the rare earth metal is also conducive to inhibiting the precipitation of other transition metals that may be added under high temperature and concentrated alkali conditions, thereby improving the stability of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a scanning electron microscope image of the multi-element alloy precursor of Example 2 of the present application before activation at a scale of 10 μm.
[0019] Figure 2 This is a scanning electron microscope image of the multi-element alloy porous electrode prepared after activation in Example 2 of the present application at a scale of 10 μm.
[0020] Figure 3 This is a scanning electron microscope image of the multi-element alloy porous electrode obtained after activation in Example 2 of the present application at a scale of 30 μm.
[0021] Figure 4 This is the element distribution diagram of the multi-element alloy precursor before activation in Example 2 of the present application.
[0022] Figure 5 This is the element distribution diagram of the multi-element alloy porous electrode obtained after activation in Example 2 of the present application.
[0023] Figure 6 In the comparative example 1 and the examples 1-2 of the present application, Ni 60 Co 20 Al 20 、Ni 55 Co 20 Al 20 Ce5、Ni 50 Co 20 Al 20 Ce 10 This is the LSV comparison diagram of hydrogen production by water electrolysis of electrodes with multi-element alloy precursors.
[0024] Figure 7 In the comparative examples 1-2 and the example 3 of the present application, Ni 60 Co 20 Al 20 、Ni 60 Co 10 Mo 10 Al 20 、Ni 50 Co 10 Mo 10 Al 20 Ce 10 This is the LSV comparison diagram of hydrogen production by water electrolysis of electrodes with multi-element alloy precursors.
[0025] Figure 8 This is a stability diagram of hydrogen production by electrolysis of water using the multi-element alloy porous electrode of Example 2 of the present application. DETAILED DESCRIPTION
[0026] The present application provides a multi-element alloy porous electrode and a preparation method and application thereof. To make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0027] The present application provides a method for preparing a multi-element alloy porous electrode, which comprises the following steps: S1. preparing a multi-element alloy precursor; S2, activating the multi-element alloy precursor to obtain a multi-element alloy porous electrode; The multi-element alloy precursor is doped with rare earth metals and Al.
[0028] The preparation method provided by the present application helps to prepare a multi-element alloy porous electrode with three-dimensional continuous pores by doping with rare earth metals, which can improve the catalytic activity. At the same time, the prepared multi-element alloy porous electrode retains the remaining rare earth metals after preparation for further self-sacrificial strategy, which can form a very small rare earth metal alloy phase, greatly promoting hydrogen production activity. At the same time, rare earth metals are also beneficial to inhibit the precipitation of other transition metals that may be added under high temperature and concentrated alkali conditions, thereby improving electrode stability.
[0029] Furthermore, the raw material of the multi-element alloy precursor is a multi-element alloy metal powder, which includes the following components calculated by mass percentage: 3wt%-25wt% of sacrificial metal, 0.5wt%-20wt% of rare earth metal, and the remainder is main metal; The sacrificial metal is Al; The rare earth metal is one or more of La, Ce, Sm, Nb, Pr, Pm, Er, and Gd; The main metal is one or more of Ni, Co, Fe, Mo, Mn, Ti and Cr.
[0030] In the present application, a multi-alloy precursor is prepared by compounding a sacrificial metal, a rare earth metal and a main metal. Al and rare earth metals will be corroded during the activation treatment, thereby preparing a multi-alloy porous electrode with three-dimensional continuous pores. The size and number of the pores can be precisely controlled by regulating the amount of rare earth metal added and the amount of Al element added, thereby optimizing the hydrogen production activity and stability.
[0031] Specifically, if the proportion of Al is too high, it will cause the collapse of the remaining alloy structure after dissolution during the activation process. If the proportion is too low, the pore structure formed will be discontinuous, or the pore structure will be less, which is not conducive to exposing more active sites and affecting the catalytic activity of the electrode. If the proportion of rare earth metals is too high, the fluidity during the smelting process will be poor, the mixing effect will be poor, and the formation of the alloy will be affected. At the same time, the rare earth will accumulate seriously, and the pores formed will be uneven, which will have a great impact on the stability of the overall structure. If the proportion is too low, it will be difficult to achieve the effect of inhibiting the dissolution of active elements. The present application is conducive to the preparation of a multi-element alloy porous electrode with a good pore structure by controlling Al and rare earth metals in a suitable proportion, which has good catalytic activity and high stability and is not easy to collapse.
[0032] Furthermore, in step S1, the step of preparing a multi-element alloy precursor includes: S11, weighing multi-element alloy metal powder according to proportion, putting it into a vacuum arc melting furnace for melting, and obtaining an alloy ingot precursor after cooling; S12. Cut the alloy ingot precursor into electrode sheet size to obtain a multi-element alloy precursor.
[0033] The metal powder raw material of the multi-element alloy metal powder can be firstly put into pure water for washing for multiple times, and then taken out for drying and standby use.
[0034] Furthermore, the smelting current is 150-220A, the smelting time is 1-5min, and the smelting is repeated at least three times under an inert atmosphere. The vacuum arc melting furnace can be evacuated to a vacuum degree of 1×10 -2 Pa, and the inert atmosphere introduced at the same time can be an argon atmosphere. The present application ensures that the components of the multi-component alloy are mixed evenly through appropriate melting conditions.
[0035] The present application obtains a multi-element alloy precursor by vacuum arc melting, and the preparation method is simple, easy to operate, and easy to mass produce.
[0036] Specifically, the alloy ingot precursor may be cut into electrode sheet sizes by wire cutting, and the size of the electrode sheet to be tested may be required, such as 1 cm*1 cm*0.1 cm.
[0037] Furthermore, in step S2, the step of activating the multi-element alloy precursor includes: The multi-element alloy precursor is placed in an alkaline solution and heated for activation to remove rare earth oxides and Al.
[0038] Specifically, vacuum arc melting is generally carried out by evacuating a vacuum and passing an inert atmosphere, but some of the remaining oxygen will react with the more reactive rare earth metals to form rare earth oxides. The present application can remove the sacrificial metal Al by heating in an alkaline solution for activation treatment, thereby forming a porous multi-element alloy electrode material with three-dimensional continuous pores in the remaining part, and the rare earth oxides formed by smelting are also removed, and pores continue to be formed on the basis of the three-dimensional pores, while retaining a small amount of rare earth metal alloy phase. The porous structure formed is conducive to substrate contact and hydrogen release, improves stability, and also exposes more remaining alloy active sites. In addition, the remaining very small amount of rare earth metal alloy phase can greatly promote hydrogen production activity while stabilizing other metals, inhibit the loss of active elements and active sites, improve stability and extend catalyst life.
[0039] Further, in step S2, the concentration of the alkaline solution is 3mol / L-8mol / L, the heating temperature is 40°C-160°C, and the activation time is 1h-144h. In the present application, the alkaline solution concentration is too low or the activation time is too short, the dissolution effect on Al is poor, and it is difficult to form a pore structure. The present application ensures that Al and rare earth oxides are removed by controlling the appropriate concentration and activation time, which is conducive to forming the desired pore structure.
[0040] Furthermore, the alkali in the alkaline solution may be one or both of potassium hydroxide and sodium hydroxide, or other strong alkalis may be selected.
[0041] The present application also provides a multi-component alloy porous electrode, wherein the electrode material is prepared by the preparation method of the multi-component alloy porous electrode as described above. The prepared electrode material can greatly improve the activity of hydrogen production by electrolysis of water, while inhibiting the dissolution of active metals, and has great industrial application prospects.
[0042] Furthermore, the multi-element alloy porous electrode includes a continuous pore structure, and the pores of the continuous pore structure are 0.5 μm-8 μm. The formed pore structure can increase the specific surface area, expose more active sites, and is conducive to improving the electrochemical performance of the multi-element alloy porous electrode.
[0043] Furthermore, the multi-element alloy porous electrode includes a rare earth metal alloy phase. Specifically, the multi-element alloy porous electrode of the present application also includes a main metal, and the selected main metal is used as a transition metal with good activity. The present application implements a further self-sacrificial strategy by doping rare earths. The remaining rare earth metal has formed a very small rare earth metal alloy phase, and the electrode has also formed a well-structured porous structure, which greatly promotes hydrogen production activity. At the same time, the rare earth metal is also conducive to inhibiting the precipitation of the remaining transition metals under high temperature and concentrated alkali conditions, thereby improving the stability of the electrode.
[0044] The present application also provides an application of the multi-component alloy porous electrode as described above, wherein the multi-component alloy porous electrode is applied to produce hydrogen by electrolysis of water. In the present application, the main metal types of the multi-component alloy porous electrode provided are widely adjustable, and the rare earth doping-self-sacrificial strategy has universal applicability, and the performance of producing hydrogen by electrolysis of water can be improved by reasonably designing the alloy composition.
[0045] The invention is further described below by means of specific examples.
[0046] Examples 1-3 Examples 1-3 are respectively based on Ni 55 Co 20 Al 20 Ce5、Ni 50 Co 20 Al 20 Ce 10 、 50 Co 10 Mo 10 Al 20 Ce 10 (subscript indicates mass ratio) is a multi-element alloy precursor. The metal raw materials are cleaned and dried. The multi-element alloy metal powders are weighed according to the element ratio, with a total mass of 40 g each. Then, the powders are evacuated to a vacuum degree of 1×10 -2 Pa, using vacuum arc, smelting 3 times in argon atmosphere, the smelting current is 200A, each time is 3min, and after cooling, alloy ingot precursors are obtained respectively; The alloy ingot precursor is cut into electrode sheets with a size of 1 cm*1 cm*0.1 cm by wire cutting to obtain multi-element alloy precursors; Then, the multi-component alloy precursors were placed in KOH with a concentration of 7.5 mol / L, activated at 95° C. for 24 h, and then cleaned with pure water to obtain the multi-component alloy porous electrodes of Examples 1-3, respectively.
[0047] Comparative Example 1-2 The preparation methods of the multi-electrode of Comparative Examples 1 and 2 are basically the same as those of Examples 1-3, except that the precursor of Comparative Example 1 is Ni 60 Co20 Al 20 (subscripts indicate mass percentage), the precursor of comparative example 2 is Ni 60 Co 10 Mo 10 Al 20 (The subscripts represent the mass percentages). After the preparation, multi-element electrodes of Comparative Example 1 and Comparative Example 2 were prepared respectively.
[0048] The scanning electron microscope image of the multi-element alloy precursor (after polishing) before activation of Example 2 is as follows: Figure 1 The scanning electron microscope image of the multi-element alloy porous electrode obtained after activation in Example 2 is shown in FIG. Figure 2 and Figure 3 As shown, by comparison, it can be found that the activated multi-element alloy porous electrode forms a porous structure with three-dimensional continuous pores with good morphology.
[0049] Example 2 The element distribution diagram of the multi-component alloy precursor before activation is as follows Figure 4 As shown, the element distribution diagram of the multi-element alloy porous electrode obtained after activation in Example 2 is as follows Figure 5 As shown, it can be found that before activation, the rare earth is a light-colored phase, and after activation, an uneven surface is formed, most of the rare earth metal has been dissolved, and the remaining rare earth metal alloy phase.
[0050] Electrochemical tests were performed in a three-electrode system using the electrodes prepared in Examples 1-3 and Comparative Examples 1-2 as working electrodes, respectively. Hg / HgO was used as a reference electrode and a Pt sheet was used as a counter electrode. Linear sweep voltammetry tests were performed in a KOH concentration of 7.5 mol / L at room temperature with a sweep rate of 5 mV / s and no iR compensation. The test results are shown in FIG. Figure 6 and 7 As shown. It can be seen that after doping with rare earth metals, the performance of the porous electrode is greatly improved. This is due to the fact that after activation by doping with rare earth, the formed pore structure can expose more active sites, and the formed rare earth metal alloy phase has high activity, which also helps to maintain the electrode performance.
[0051] The multi-electrode alloy porous electrode prepared in Example 2 was used as an electrode to conduct stability test in a two-electrode system. The nickel mesh was used as a counter electrode. The current was measured at 85°C in a KOH concentration of 7.5 mol / L with a chronoamperometric current density of 500 mA / cm 2 , the test results are as follows Figure 8 As shown in the figure, it can still maintain good stability after 165h.
[0052] The multi-component alloys prepared in Examples 1-3 and Comparative Examples 1-2 were sliced and immersed in a KOH solution at 90° C. and a concentration of 7.5 mol / L for 336 hours, and the metal dissolution was tested. The test results are shown in Table 1: Table 1 Multi-element alloy slices Initial weight / g Dissolution mass / mg <![CDATA[Ni 60 What 20 Al 20 ]]> 0.3150 Ni:0;Al:1.164;Co:0.018 <![CDATA[Ni 55 What 20 Al 20 Ce5]]> 0.2940 Ni:0;Co:0;Al:0.428;Ce:0 <![CDATA[Ni 50 Co. 20 the 20 What 10 ]]> 0.9142 Ni:0;Al:2.308;Co:0;Ce:0 <![CDATA[Ni 60 Co 10 Mo 10 Al 20 ]]> 0.2936 Ni:0;Al:0.086;Mo:0.534;Co:0 <![CDATA[Ni 50 Co. 10 Mo 10 the 20 What 10 ]]> 0.4465 Ni:0;Al:0.428;Mo:0.108;Co:0;Ce:0 It can be found from Table 1 that the dissolution of active elements Co and Mo decreases after doping with rare earth metals, indicating that rare earth doping can inhibit the dissolution of active elements and is beneficial to maintaining the activity of the electrode.
[0053] The present application forms larger three-dimensional continuous pores after activation by doping Al and rare earth metals into a multi-element alloy precursor, and the rare earth metals can also assist in forming a porous structure. More importantly, the dissolution and loss of active elements can be inhibited to maintain stability, which can greatly improve the activity of hydrogen production by electrolysis of water while improving stability, and has great industrial application prospects.
[0054] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the scope of protection of the present application.
Claims
1. A method for preparing a multi-element alloy porous electrode, characterized in that: The following steps are involved: preparing a multi-element alloy precursor; Activating the multi-component alloy precursor to obtain the multi-component alloy porous electrode; The multi-element alloy precursor is doped with rare earth metal and Al.
2. The method for preparing a multi-element alloy porous electrode according to claim 1, characterized in that: The raw material of the multi-element alloy precursor is multi-element alloy metal powder, which includes the following components calculated by mass percentage: Sacrificial metal 3wt% -25wt%, rare earth metal 0.5wt% -20wt%, the remainder is main metal; The sacrificial metal is Al; The rare earth metal is one or more of La, Ce, Sm, Nb, Pr, Pm, Er, and Gd; The main metal is one or more of Ni, Co, Fe, Mo, Mn, Ti and Cr.
3. The method for preparing a multi-element alloy porous electrode according to claim 2, characterized in that: The step of preparing the multi-element alloy precursor comprises: Weigh the multi-element alloy metal powder according to proportion, put it into a vacuum arc melting furnace for melting, and obtain an alloy ingot precursor after cooling; The alloy ingot precursor is cut into electrode sheet sizes.
4. The method for preparing a multi-element alloy porous electrode according to claim 3, characterized in that: The smelting current is 150-220A and the smelting time is 1-5min; The melting was repeated at least three times under argon atmosphere.
5. The method for preparing a multi-element alloy porous electrode according to claim 1, characterized in that: The step of activating the multi-element alloy precursor comprises: The multi-element alloy precursor is placed in an alkaline solution for heating and activation to remove rare earth oxides and Al.
6. The method for preparing a multi-element alloy porous electrode according to claim 5, characterized in that: The concentration of the alkaline solution is 3 mol / L-8 mol / L, the heating temperature is 40°C-160°C, and the activation time is 1h-144h; The alkali in the alkaline solution is one or both of potassium hydroxide and sodium hydroxide.
7. A multi-element alloy porous electrode, characterized in that: The porous electrode is prepared by the method for preparing a multi-element alloy as described in any one of claims 1 to 6.
8. The multi-element alloy porous electrode according to claim 7, characterized in that: The multi-element alloy porous electrode comprises a continuous pore structure, and the pore diameter of the continuous pore structure is 0.5 μm-8 μm.
9. The multi-element alloy porous electrode according to claim 7, characterized in that: The multi-element alloy porous electrode includes a rare earth metal alloy phase.
10. An application of the multi-element alloy porous electrode as claimed in any one of claims 7 to 9, characterized in that: The multi-element alloy porous electrode is applied to produce hydrogen by electrolyzing water.