Pt-Ni (OH) 2 composite hydrogen evolution catalyst and preparation method and application thereof

Abstract

The invention discloses a Pt-Ni (OH) 2 composite hydrogen evolution catalyst and a preparation method and application thereof.The preparation method of the Pt-Ni (OH) 2 composite hydrogen evolution catalyst comprises the following steps that a platinum source, metal nickel salt and urea are dissolved in a solvent and dispersed, and a mixed solution is obtained; transferring the mixed solution into a reaction kettle, carrying out hydrothermal reaction, cooling, and carrying out solid-liquid separation on a reaction product to obtain a solid product; and finally, washing the solid product, and freeze-drying to obtain the product. According to the Pt-Ni (OH) 2 composite hydrogen evolution catalyst prepared by adopting a one-step solvothermal method, the alpha-Ni (OH) 2 component can obviously improve the hydrogen evolution catalytic activity in an alkaline electrolyte; and the interlayer spacing of alpha-Ni (OH) 2 is further expanded, so that more active sites can be exposed, the mass transfer process is accelerated, the electron transfer path is improved, the proton conductivity is improved, rapid transfer of reactants and products is promoted, and the catalytic activity is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a Pt-Ni(OH)2 composite hydrogen evolution catalyst and a preparation method and application thereof. Background Art

[0002] Producing hydrogen from water electrolysis using renewable energy is a safe, environmentally friendly and efficient way to produce hydrogen. Theoretically, it can achieve a thermodynamic conversion efficiency of 80%. The produced hydrogen is called "green hydrogen" and has broad development prospects.

[0003] The hydrogen evolution reaction at the cathode of water electrolysis includes three possible steps: the first step of Volmer reaction, and the subsequent Heyrovsky reaction or Tafel reaction. Platinum (Pt) is considered to be the best element for catalyzing the hydrogen evolution reaction. However, under alkaline conditions, due to the slow water dissociation and poor proton supply rate, the kinetics of the hydrogen evolution reaction on Pt is significantly slower, resulting in a reaction rate that is often 2-3 orders of magnitude lower than that in acidic electrolytes. Nickel (Ni) hydroxide is usually used to improve the catalytic activity of Pt in alkaline water electrolysis because of its strong water dissociation ability. Traditional Pt-Ni(OH)2 composite catalysts are usually prepared by a two-step method, that is, first preparing Ni(OH)2 and then reducing Pt to the Ni(OH)2 surface. The preparation process is relatively cumbersome and not conducive to the large-scale preparation of the catalyst. In addition, the catalytic activity of the prepared Pt-Ni(OH)2 composite catalyst is not ideal.

[0004] Therefore, there is an urgent need to develop a simple and rapid method for preparing Pt-Ni(OH)2 composite catalysts, and to make the prepared catalysts have high catalytic activity for hydrogen production by alkaline water electrolysis. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a Pt-Ni(OH)2 composite hydrogen evolution catalyst and a preparation method and application thereof. The preparation method adopts a one-step solvothermal method, which can simply, quickly and large-scale prepare the Pt-Ni(OH)2 composite hydrogen evolution catalyst, and the Pt in the composite hydrogen evolution catalyst is inserted into the interlayer of α-Ni(OH)2, and the interlayer distance of α-Ni(OH)2 is expanded, so that more active sites are exposed, thereby accelerating the mass transfer process and improving the catalytic performance of hydrogen evolution in alkaline water electrolysis.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst, comprising the following steps:

[0007] (1) dissolving a platinum source, a metal nickel salt, and urea in a solvent, and dispersing the mixture to obtain a mixed solution;

[0008] (2) transferring the mixed solution to a reaction vessel for hydrothermal reaction, and after cooling, performing solid-liquid separation on the reaction product to obtain a solid product;

[0009] (3) washing and freeze-drying the solid product to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst.

[0010] Specifically, the present invention adopts a one-step solvothermal method to prepare a Pt-Ni(OH)2 composite hydrogen evolution catalyst. Compared with the traditional two-step method, not only is the preparation method simpler and suitable for large-scale production, but also in the prepared composite hydrogen evolution catalyst, the Ni(OH)2 component can quickly dissociate water molecules in the alkaline electrolyte into protons, and then quickly transfer them to the Pt site, where a rapid Tafel reaction occurs, significantly improving the hydrogen evolution catalytic activity in the alkaline electrolyte. At the same time, in the composite hydrogen evolution catalyst prepared by the one-step solvothermal method, Pt is inserted into the interlayer of α-Ni(OH)2, so that it has an enlarged interlayer distance, which can expose more active sites, and can accelerate the mass transfer process, improve the electron transfer path, improve the proton conductivity, and promote the rapid transfer of reactants and products, thereby effectively improving the catalytic activity.

[0011] In some embodiments of the present invention, the platinum source is selected from at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, potassium tetrachloroplatinite, and sodium tetrachloroplatinite.

[0012] In some embodiments of the present invention, the metal nickel salt is selected from at least one of nickel chloride, nickel nitrate, and nickel sulfate, for example, nickel nitrate and its hydrate, nickel chloride and its hydrate, and nickel sulfate and its hydrate.

[0013] In some embodiments of the present invention, the mass ratio of the platinum source to the metal nickel salt is 10:(1-100). Preferably, the mass ratio of the platinum source to the metal nickel salt is 10:(10-50). Further preferably, the mass ratio of the platinum source to the metal nickel salt is 10:(20-40).

[0014] In some embodiments of the present invention, the mass ratio of the metal nickel salt to urea is 1:(0.1-10). Preferably, the mass ratio of the metal nickel salt to urea is 1:(0.5-5). Further preferably, the mass ratio of the metal nickel salt to urea is 1:(0.8-4).

[0015] In some embodiments of the present invention, the solvent comprises ethylene glycol and water.

[0016] In some embodiments of the present invention, the volume ratio of ethylene glycol to water is 10:(1-10). Preferably, the volume ratio of ethylene glycol to water is 10:(1-5). Further preferably, the volume ratio of ethylene glycol to water is 10:(1-3).

[0017] In some embodiments of the present invention, the temperature of the hydrothermal reaction is 120-180° C. Preferably, the temperature of the hydrothermal reaction is 140-160° C.

[0018] In some embodiments of the present invention, the hydrothermal reaction time is 0.5-6 hours. Preferably, the hydrothermal reaction time is 2-6 hours.

[0019] The second aspect of the present invention provides a Pt-Ni(OH)2 composite hydrogen evolution catalyst, which is prepared by the above-mentioned preparation method. The Pt-Ni(OH)2 composite hydrogen evolution catalyst comprises Pt and α-Ni(OH)2, wherein the Pt is inserted into the interlayer of α-Ni(OH)2 and expands the interlayer distance of α-Ni(OH)2.

[0020] Specifically, the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared by the present invention includes Pt and α-Ni(OH)2, and α-Ni(OH)2 is composed of Ni(OH)2 layers embedded with anions or water molecules, which has a stronger mass transfer ability than β-Ni(OH)2 formed by hexagonal close packing, and therefore has a higher catalytic activity. At the same time, Pt is inserted into the interlayer of α-Ni(OH)2, so that the interlayer spacing of α-Ni(OH)2 is further expanded. The expanded interlayer spacing can expose more active sites on the one hand, and on the other hand, it is conducive to accelerating the mass transfer process, improving the electron transfer path, improving proton conductivity, and promoting the rapid transfer of reactants and products, thereby effectively improving the catalytic activity.

[0021] The third aspect of the present invention provides the use of the above-mentioned Pt-Ni(OH)2 composite hydrogen evolution catalyst in hydrogen production by alkaline water electrolysis. The Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared by the present invention exhibits good electrocatalytic hydrogen evolution activity under alkaline conditions.

[0022] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0023] (1) The present invention adopts a one-step solvothermal method to prepare a Pt-Ni(OH)2 composite hydrogen evolution catalyst, wherein the Ni(OH)2 component can quickly dissociate water molecules in an alkaline electrolyte into protons, which are then quickly transferred to the Pt site, and a rapid Tafel reaction occurs at the Pt site, significantly improving the hydrogen evolution catalytic activity in the alkaline electrolyte. At the same time, in the composite catalyst prepared by the one-step solvothermal method, the interlayer spacing of α-Ni(OH)2 is further expanded, which can expose more active sites, and at the same time can accelerate the mass transfer process, improve the electron transfer path, increase proton conductivity, and promote the rapid transfer of reactants and products, thereby effectively improving the catalytic activity.

[0024] (2) The one-step solvothermal method used in the present invention for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst is simple, fast, and efficient, the reaction conditions are controllable, the utilization rate of the precious metal Pt is high, the prepared catalyst has good uniformity, and is suitable for mass production.

[0025] (3) The Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared by the present invention has good electrocatalytic hydrogen evolution performance. When the current density reaches -10mAcm -2 The overpotential is 39-46 mV, which is better than that of commercial platinum-carbon catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst according to the present invention;

[0027] Figure 2 The X-ray diffraction pattern of the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared in Example 1-2 of the present invention;

[0028] Figure 3 The X-ray diffraction pattern of the hydrogen evolution catalyst prepared in Comparative Example 2-3 of the present invention;

[0029] Figure 4 This is a comparison diagram of the electrochemical polarization curves of the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared in Examples 1-3 of the present invention in 1M potassium hydroxide solution. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0031] like Figure 1 As shown, the preparation method of the Pt-Ni(OH)2 composite hydrogen evolution catalyst provided by the present invention comprises the following steps:

[0032] (1) dissolving a platinum source, a metal nickel salt, and urea in a mixed solution of ethylene glycol and water, and stirring to make them uniformly dispersed to obtain a mixed solution;

[0033] (2) transferring the mixed solution obtained in step (1) into a reaction vessel and performing a hydrothermal reaction to obtain a reaction product;

[0034] (3) The reaction product obtained in step (2) is centrifuged, washed and freeze-dried to obtain a Pt-Ni(OH)2 composite hydrogen evolution catalyst.

[0035] Example 1

[0036] A method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst comprises the following steps:

[0037] (1) Weighing 0.6 g of nickel nitrate hexahydrate, 0.5 g of urea, and 0.2 g of potassium chloroplatinate respectively, dissolving them in a mixed solution of 4 ml of water and 28 ml of ethylene glycol solution, stirring them thoroughly, and ultrasonicating them to completely dissolve them, to obtain a mixed solution;

[0038] (2) transferring the mixed solution obtained in step (1) into a reaction kettle, performing a hydrothermal reaction at 140° C. for 2 hours, cooling naturally to room temperature, and centrifuging the reaction product for solid-liquid separation to obtain a solid product;

[0039] (3) The solid product obtained in step (2) was washed three times with ultrapure water and ethanol respectively, and then freeze-dried to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst of this embodiment.

[0040] Example 2

[0041] A method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst comprises the following steps:

[0042] (1) Weighing 0.6 g of nickel nitrate hexahydrate, 2.0 g of urea, and 0.2 g of chloroplatinic acid hexahydrate, respectively, dissolving them in a mixed solution of 4 ml of water and 28 ml of ethylene glycol solution, stirring them thoroughly, and ultrasonicating them to completely dissolve them, to obtain a mixed solution;

[0043] (2) transferring the mixed solution obtained in step (1) into a reaction kettle, performing a hydrothermal reaction at 140° C. for 2 hours, cooling naturally to room temperature, and centrifuging the reaction product for solid-liquid separation to obtain a solid product;

[0044] (3) The solid product obtained in step (2) was washed three times with ultrapure water and ethanol respectively, and then freeze-dried to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst of this embodiment.

[0045] Example 3

[0046] A method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst comprises the following steps:

[0047] (1) Weighing 0.6 g of nickel nitrate hexahydrate, 0.5 g of urea, and 0.2 g of potassium chloroplatinate respectively, dissolving them in a mixed solution of 4 ml of water and 28 ml of ethylene glycol solution, stirring them thoroughly, and ultrasonicating them to completely dissolve them, to obtain a mixed solution;

[0048] (2) transferring the mixed solution obtained in step (1) into a reaction kettle, performing a hydrothermal reaction at 160° C. for 6 hours, cooling naturally to room temperature, and centrifuging the reaction product for solid-liquid separation to obtain a solid product;

[0049] (3) The solid product obtained in step (2) was washed three times with ultrapure water and ethanol respectively, and then freeze-dried to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst of this embodiment.

[0050] Comparative Example 1

[0051] A commercially available Pt / C catalyst (TANAKATK, model: TEC10E20E, platinum loading of 20 wt.%) was used as the hydrogen evolution catalyst in Comparative Example 1.

[0052] Comparative Example 2

[0053] The difference between Comparative Example 2 and Example 1 is that the prepared hydrogen evolution catalyst does not contain Pt and is a single α-Ni(OH)2, and its preparation method comprises the following steps:

[0054] (1) Weighing 0.6 g of nickel nitrate hexahydrate and 0.5 g of urea respectively, dissolving them in a mixed solution of 4 ml of water and 28 ml of ethylene glycol solution, stirring them thoroughly and ultrasonicating them to completely dissolve them, to obtain a mixed solution;

[0055] (2) transferring the mixed solution obtained in step (1) into a reaction kettle, performing a hydrothermal reaction at 140° C. for 2 hours, cooling naturally to room temperature, and centrifuging the reaction product for solid-liquid separation to obtain a solid product;

[0056] (3) The solid product obtained in step (2) was washed three times with ultrapure water and ethanol respectively, and then freeze-dried to obtain the α-Ni(OH)2 hydrogen evolution catalyst of this comparative example.

[0057] Comparative Example 3

[0058] The difference between Comparative Example 3 and Example 1 is that a two-step solvothermal method is used to prepare the Pt-Ni(OH)2 composite hydrogen evolution catalyst, and the preparation method thereof comprises the following steps:

[0059] (1) Weighing 0.6 g of nickel nitrate hexahydrate and 0.5 g of urea respectively, dissolving them in a mixed solution of 4 ml of water and 28 ml of ethylene glycol solution, stirring them fully, and ultrasonicating them to completely dissolve them to obtain a mixed solution; then transferring the mixed solution to a reactor, performing a hydrothermal reaction at 140° C. for 2 hours, cooling them naturally to room temperature, and performing solid-liquid separation on the reaction product to obtain a solid product; then washing the obtained solid product with ultrapure water and ethanol for three times respectively, and finally freeze-drying them to obtain an α-Ni(OH)2 hydrogen evolution catalyst;

[0060] (2) dispersing the α-Ni(OH)2 hydrogen evolution catalyst prepared in step (1) and 0.2 g of potassium chloroplatinate in 20 ml of ethylene glycol solution, stirring and ultrasonicating to completely dissolve the potassium chloroplatinate and evenly disperse the α-Ni(OH)2; then transferring the dispersed solution to a reactor, reacting at 140° C. for 2 hours, and cooling the reaction product to room temperature naturally to obtain a reaction product; then centrifuging the reaction product for solid-liquid separation to obtain a solid product;

[0061] (3) The solid product obtained in step (2) was washed three times with ultrapure water and ethanol respectively; then freeze-dried to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst of this comparative example.

[0062] Performance Testing

[0063] 1. Component Analysis

[0064] Figure 2 The X-ray diffraction pattern of the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared in Example 1-2 of the present invention is as follows: Figure 2The horizontal axis 2-Theta represents the 2θ angle, and the vertical axis Intensity represents the intensity of the diffraction peak. Among them: the diffraction peaks at 39.6°, 46.5° and 67.5° correspond to the (111), (200) and (220) crystal planes of Pt respectively; the diffraction peaks at 33.4° and 59.9° correspond to the (101) and (110) crystal planes of α-Ni(OH)2 respectively, and the diffraction peak near 10° corresponds to the (003) crystal plane of α-Ni(OH)2.

[0065] Figure 3 The X-ray diffraction patterns of the hydrogen evolution catalysts prepared in Comparative Examples 2-3 of the present invention are consistent with the standard card (JCPDS 38-0715) in which the diffraction peaks at 11.3°, 22.7°, 33.4° and 59.9° correspond to the (003), (006), (101) and (110) crystal planes of α-Ni(OH)2, respectively. The Pt-Ni(OH)2 hydrogen evolution catalyst sample prepared in Comparative Example 3 exhibits similar diffraction peaks of α-Ni(OH)2, and the diffraction peaks at 39.6°, 46.5° and 67.5° correspond to the (111), (200) and (220) crystal planes of Pt, respectively.

[0066] α-Ni(OH)2 is composed of Ni(OH)2 layers embedded with anions or water molecules, and has a stronger mass transfer capacity than β-Ni(OH)2 formed by hexagonal close packing. Therefore, α-Ni(OH)2 has higher catalytic activity than β-Ni(OH)2. Figure 2 and Figure 3 By comparison, it can be seen that in the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared in Examples 1-2 of the present invention, the (003) crystal plane of α-Ni(OH)2 has a significant shift to a low angle (from 11.3° to 10°) compared to Comparative Examples 2 and 3, which indicates that the interlayer spacing of α-Ni(OH)2 in the composite catalyst prepared by the one-step solvothermal method is further expanded. The reason may be due to the insertion of Pt into the interlayer of the octahedral α-Ni(OH)6. This further expanded interlayer spacing can expose more active sites on the one hand, and on the other hand, it can speed up the mass transfer process, improve the electron transfer path, improve the proton conductivity, and promote the rapid transfer of reactants and products, thereby effectively improving the catalytic activity.

[0067] 2. Electrocatalytic hydrogen evolution performance

[0068] A 1 mol / L potassium hydroxide solution was prepared as an electrocatalytic electrolyte, and the Pt-Ni(OH)2 composite hydrogen evolution catalyst, Hg / HgO electrode, and carbon rod electrode prepared in Examples 1-3 were respectively used as a working electrode, a reference electrode, and a counter electrode, respectively, and connected to an electrochemical workstation. A linear voltammetric test was performed on the electrode material at a scan rate of 10 mV / s. The electrochemical polarization curves were as shown in FIG. Figure 4 As shown, Figure 4 The horizontal axis Potential represents voltage, and the vertical axis Current density represents current density. Figure 4 It can be seen that when the current density reaches 10mAcm -2 When the overpotential of the Pt-Ni(OH)2 composite hydrogen evolution catalyst prepared in Examples 1-3 is 39-46 mV. The electrocatalytic hydrogen evolution performance of the hydrogen evolution catalyst prepared in Comparative Examples 1-3 was measured by the same test method, and the results are shown in Table 1.

[0069] Table 1:

[0070] sample <![CDATA[10mAcm -2 Overpotential at (mV)]]> Example 1 39 Example 2 46 Example 3 42 Comparative Example 1 56 Comparative Example 2 120 Comparative Example 3 63

[0071] As shown in Table 1, the Pt-Ni(OH)2 composite hydrogen evolution catalysts prepared in Examples 1-3 of the present invention all have good electrocatalytic hydrogen evolution performance, 10 mA cm -2 The overpotential is as low as 39-46 mV, which is better than the electrocatalytic hydrogen evolution performance of the commercially available Pt / C catalyst in Comparative Example 1.

[0072] Compared with Example 1, the hydrogen evolution catalyst of Comparative Example 2 does not contain Pt, and its 10mAcm -2 The overpotential is 120 mV, which is much higher than 39 mV in Example 1, indicating that Pt has a good promoting effect on the electrocatalytic hydrogen evolution performance of α-Ni(OH)2.

[0073] The hydrogen evolution catalyst of Comparative Example 3, relative to Example 1, adopts the traditional two-step solvothermal method, in which Pt is loaded on the surface of Ni(OH)2 in the prepared Pt-Ni(OH)2 composite hydrogen evolution catalyst, the interlayer spacing of Ni(OH)2 is not enlarged, and the exposed active sites are less than those in Example 1. Therefore, the catalytic activity is not as good as that in Example 1.

[0074] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. A method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst, characterized in that: The following steps are involved: (1) dissolving a platinum source, a metal nickel salt, and urea in a solvent, and dispersing the mixture to obtain a mixed solution; (2) transferring the mixed solution to a reaction vessel for hydrothermal reaction, and after cooling, performing solid-liquid separation on the reaction product to obtain a solid product; (3) washing and freeze-drying the solid product to obtain the Pt-Ni(OH)2 composite hydrogen evolution catalyst.

2. The method for preparing a Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The platinum source is selected from at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, potassium tetrachloroplatinite and sodium tetrachloroplatinite.

3. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The metal nickel salt is selected from at least one of nickel chloride, nickel nitrate and nickel sulfate.

4. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The mass ratio of the platinum source to the metal nickel salt is 10:(1-100).

5. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The mass ratio of the metal nickel salt to urea is 1:(0.1-10).

6. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The solvents include ethylene glycol and water.

7. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 6, characterized in that: The volume ratio of the ethylene glycol to water is 10:(1-10).

8. The method for preparing the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 120-180° C.; and / or the time of the hydrothermal reaction is 0.5-6 hours.

9. A Pt-Ni(OH)2 composite hydrogen evolution catalyst, characterized in that: The Pt-Ni(OH)2 composite hydrogen evolution catalyst is prepared by the preparation method according to any one of claims 1 to 8, wherein the Pt-Ni(OH)2 composite hydrogen evolution catalyst comprises Pt and α-Ni(OH)2, wherein the Pt is inserted into the interlayer of α-Ni(OH)2 and expands the interlayer distance of α-Ni(OH)2.

10. Use of the Pt-Ni(OH)2 composite hydrogen evolution catalyst according to claim 9 in hydrogen production by alkaline water electrolysis.

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