Amorphous reconstructed hydrogen evolution catalyst and preparation method and application thereof

Abstract

The invention relates to an amorphous reconstruction hydrogen evolution catalyst and a preparation method and application thereof. The amorphous reconstruction hydrogen evolution catalyst is of a heterostructure, the surface layer of the amorphous reconstruction hydrogen evolution catalyst is a transition metal oxide, and the inner layer of the amorphous reconstruction hydrogen evolution catalyst is a transition metal boride or a transition metal boron-phosphorus co-doped compound; the transition metal oxide, the transition metal boride and the transition metal boron-phosphorus co-doped compound are all in an amorphous state; transition metals in the amorphous state reconstruction hydrogen evolution catalyst are at least two of Fe, Co, Ni, Ce, Cu, Mn, V, W and Mo.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical catalytic electrode technology, specifically relating to an amorphous reconstructed hydrogen evolution catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as an excellent alternative to traditional fossil fuels, has attracted considerable interest. Water electrolysis is a highly efficient method for producing green hydrogen using clean energy sources such as solar or wind power. This method involves the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. However, large overpotentials increase the energy consumption and cost of water electrolysis, hindering its development. Using noble metal electrocatalysts such as Pt, RuO2, and IrO2 can effectively reduce the overpotentials of HER and OER and accelerate the reaction process; however, traditional powdered noble metal catalysts have poor stability. Therefore, finding stable and widely applicable electrocatalysts to achieve cost-effective water electrolysis for hydrogen production remains a highly challenging goal.

[0003] Currently, numerous novel transition metal-based electrocatalysts have been reported through various synthetic strategies. For example, Shao et al. altered the proximity configuration of cobalt-based perovskites by controlling peroxide vacancies (Adv. Funct. Mater. 2019, 29, 1900704), thus exhibiting excellent HER activity. More interestingly, catalysts have been shown to undergo structural reconstruction during electrochemical reactions to form truly catalytically active materials, especially in OER. However, most synthesized catalysts currently exhibit relatively stable crystalline structures. Therefore, structural reconstruction is difficult to occur during HER electrochemistry. In addition, crystalline catalyst materials usually require complex and / or harsh synthetic conditions. Recently, Xie et al. revealed that lattice distortion or defects in the precatalyst may be the main reason for material reconstruction during HER (Angew. Chem. Int. Ed. 2021, 60, 21575). In summary, there is an urgent need to develop HER catalyst materials that readily undergo structural reconstruction to significantly improve the HER catalytic activity of catalysts. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a mild, flexible, and controllable method for constructing a novel class of high-performance amorphous catalysts composed of amorphous metal borides. Furthermore, an electrochemical activation strategy is employed to significantly enhance the catalytic activity and stability of the amorphous catalysts.

[0005] In a first aspect, the present invention provides an amorphous reconstructed hydrogen evolution catalyst, wherein the amorphous reconstructed hydrogen evolution catalyst has a heterogeneous structure, wherein the surface layer is a transition metal oxide and the inner layer is a transition metal boride or a transition metal boron-phosphorus co-doped compound; wherein the transition metal oxide, transition metal boride and transition metal boron-phosphorus co-doped compound are all amorphous; wherein the transition metal in the amorphous reconstructed hydrogen evolution catalyst is at least two of Fe, Co, Ni, Ce, Cu, Mn, V, W and Mo.

[0006] Preferably, the transition metal oxide has a nanosheet structure; more preferably, the size of the transition metal oxide is 50-100 nm; more preferably, the transition metal oxide is cobalt oxide.

[0007] Preferably, the transition metal boride is NiFeB or / and NiCoB; The transition metal boron-phosphorus co-doped compound is at least one of NiCoBP, NiFeBP, NiFeCoBP, NiBP, and CoBP.

[0008] Preferably, the content of transition metal in the surface layer of the amorphous reconstructed hydrogen evolution catalyst is 30wt% to 65wt%, with the balance being oxygen. In the inner layer of the amorphous reconstructed hydrogen evolution catalyst, the content of transition metal is 60-85 wt%, and the content of boron and / or phosphorus is 15-40 wt%.

[0009] Preferably, the transition metals in the amorphous reconstructed hydrogen evolution catalyst are Ni and Co; more preferably, the mass ratio of Ni to Co is 2.5:(0.1-1).

[0010] Secondly, the present invention provides a method for preparing an amorphous reconstructed hydrogen evolution catalyst, comprising: (1) A chemical plating solution is obtained by mixing a transition metal salt, a stabilizer, a complexing agent, a reducing agent and a solvent; (2) The substrate is immersed in the obtained chemical plating solution for reaction, and after washing and drying, an amorphous catalyst is obtained; (3) The obtained amorphous catalyst is subjected to electrochemical activation treatment to obtain the amorphous reconstructed hydrogen evolution catalyst.

[0011] Preferably, the metal cation in the transition metal salt is selected from at least one of Fe, Co, Ni, Ce, Cu, Mn, V, W, and Mo; The concentration of transition metal salts in the electroless plating solution is 1–100 g / L.

[0012] Preferably, the stabilizer is selected from at least one of ethylenediamine, phosphoric acid, citric acid, carbonic acid, and acetic acid.

[0013] Preferably, the concentration of the stabilizer in the electroless plating solution is 1–25 g / L.

[0014] Preferably, the complexing agent is selected from at least one of hydroxides, citrates, pyrophosphates, thiosulfates, and sulfites.

[0015] Preferably, the concentration of the complexing agent in the electroless plating solution is 1–50 g / L.

[0016] Preferably, the reducing agent is at least one of sodium borohydride, DMAB, and hydrazine hydrate.

[0017] Preferably, the concentration of the reducing agent in the electroless plating solution is 1–25 g / L.

[0018] Preferably, the solvent is selected from deionized water.

[0019] Preferably, the pH value of the electroless plating solution is 2 to 14; more preferably, the pH value of the electroless plating solution is 6 to 10.

[0020] Preferably, water, ethanol, or acetone is used as a washing solution to clean the substrate and remove surface impurities; the substrate is a conductive substrate or an insulating substrate. The conductive substrate is preferably a metal substrate, more preferably a foamed metal substrate, and most preferably a foamed nickel substrate; The insulating substrate is made of sponge, filter paper, carbon felt, or graphite paper.

[0021] Preferably, the reaction is carried out at a temperature of 10–80°C for a time of 0.5–12 h.

[0022] Preferably, the amorphous catalyst has an amorphous structure composed of amorphous materials; the amorphous materials are transition metal borides or transition metal boron-phosphorus co-doped compounds; the amorphous materials are at least one of NiFeB, NiCoB, NiCoBP, NiFeBP, and NiFeCoBP.

[0023] Preferably, the electrochemical activation parameters include: the activation solution is an alkaline solution with a concentration of 0.1 to 10 M; the activation voltage is -4.0 V to -0.2 V; more preferably, the activation solution is a KOH solution with a concentration of 0.1 to 10 M or a NaOH solution with a concentration of 0.1 to 10 M; and the activation voltage is -1.5 V to -0.7 V.

[0024] Preferably, the electrochemical activation is performed by cyclic voltammetry or linear scan method; more preferably, the electrochemical activation is performed by cyclic voltammetry; the parameters of the cyclic voltammetry include: the activation solution is a KOH solution with a concentration of 0.1 to 10 M or a NaOH solution with a concentration of 0.1 to 10 M; the activation voltage is -1.5 V to -0.7 V.

[0025] Chemical plating is defined as a simple and mild autocatalytic deposition method. This invention uses chemical plating to prepare amorphous hydrogen evolution catalysts. The composition of the catalyst is flexibly controlled by selecting / designing raw materials, solutions, and operating conditions. Subsequent electrochemical activation significantly enhances the catalytic activity and stability of the amorphous catalyst. This electrochemical activation is a reconstruction process that promotes the production of a large number of catalytically active substances on the catalyst surface, thereby significantly improving the catalyst's catalytic activity. Compared to crystalline materials, amorphous materials have long-range disordered atomic arrangements and numerous defect sites, such as unsaturated coordination, vacancies, and dangling bonds. These defects can trigger spontaneous reconstruction of the catalyst during the electrocatalytic reaction, leading to the formation of more active new sites and thus exhibiting superior electrocatalytic performance. Specifically, during the hydrogen evolution reaction, the morphology and composition of the catalyst differ significantly from the original catalyst. After activation, a nanosheet structure (transition metal oxide) is formed on the surface, exhibiting good gas-repellent properties, which is more conducive to the exposure of catalytically active sites, thereby significantly improving the catalyst's catalytic activity.

[0026] Thirdly, the present invention provides a modified matrix, comprising: a matrix, and an amorphous reconstructed hydrogen evolution catalyst in situ supported on the matrix; wherein the matrix is ​​a conductive matrix or an insulating matrix; The conductive substrate is preferably a metal substrate, more preferably a foamed metal substrate, and most preferably a foamed nickel substrate; The insulating substrate is made of sponge, filter paper, carbon felt, or graphite paper.

[0027] Fourthly, this invention provides an application of an amorphous reconstructed hydrogen evolution catalyst in the electrocatalytic hydrogen evolution reaction, wherein the modified amorphous reconstructed hydrogen evolution catalyst electrode is used as the working electrode and placed in an electrolyte at 10–2500 mA / cm². -2 At the operating current density, it exhibits excellent hydrogen evolution catalytic performance; Preferably, the electrolyte is an alkaline solution with a concentration of 0.1–10 M; more preferably, it is a NaOH solution with a concentration of 0.1–10 M or a KOH solution with a concentration of 0.1–10 M. Preferably, the counter electrode is a graphite carbon rod; the reference electrode is mercury / mercury oxide.

[0028] The beneficial effects of this invention are: (1) The preparation method of the present invention is mild, simple to operate, and has good repeatability. It can be operated online or offline, and has significant and fast effects. It can greatly improve the hydrogen evolution performance and stability of amorphous transition metal borides in water electrolysis. (2) The electrocatalytic hydrogen evolution performance of the amorphous reconstructed hydrogen evolution catalyst prepared by the method of the present invention is significantly improved. The activated amorphous catalyst can reach 500 mA cm⁻¹ with only 175 mV overpotential in 1 mol / L potassium hydroxide solution. -2 ; (3) The preparation method of the amorphous reconstructed hydrogen evolution catalyst of the present invention is simple, the materials are widely applicable and the cost is low, and it has industrial practical value in the fields of water electrolysis and electrocatalysis. Attached Figure Description

[0029] Figure 1 Ni prepared by electroless plating 2.5 Co 0.5 Scanning electron microscope image of the amorphous catalyst B; Figure 2 Ni after activation 2.5 Co 0.5 Scanning electron microscope image of the amorphous catalyst B; Figure 3 For Ni 2.5 Co 0.5 Test results of hydrogen evolution performance of B / NF electrode before and after activation; Figure 4 For Ni 2.5 Co 0.5 Test results of hydrogen evolution stability of B / NF electrode under high current density; Figure 5 For different proportions of Ni x Co y Test results of hydrogen evolution performance of electrode B; Figure 6 For Ni 2.5 Co 0.5 Results of hydrogen evolution performance tests of the BP electrode at 25℃ and 60℃. Detailed Implementation

[0030] To further illustrate the invention's content, features, and practical effects, the invention will be described in detail below with reference to embodiments. It should be noted that the modification methods of the invention are not limited to these specific implementation methods. Equivalent substitutions and modifications made by those skilled in the art based on their reading of the invention, without departing from its spirit and essence, are also within the scope of protection claimed by the invention. Unless otherwise specified, percentage content refers to mass percentage content.

[0031] In this invention, a simple and efficient preparation strategy is used to construct amorphous catalysts, and electrochemical activation (reconstruction) is used to significantly improve the electrocatalytic performance of amorphous catalysts, such as hydrogen evolution activity, high stability, and high current operating characteristics.

[0032] Specifically, this invention first prepares an amorphous catalyst using chemical plating. The amorphous catalyst has an amorphous structure composed of amorphous materials, specifically transition metal borides or transition metal boron-phosphorus co-doped compounds. After electrochemical activation, the transition metal borides or boron-phosphorus co-doped compounds undergo compositional and structural reconstruction on their surface. The reconstructed catalyst (amorphous reconstructed hydrogen evolution catalyst) exhibits a heterogeneous structure, with a transition metal oxide surface and a transition metal boride or boron-phosphorus co-doped compound inner layer. Specifically, the transition metal content in the inner layer of the obtained amorphous reconstructed hydrogen evolution catalyst is 60–85 wt%, and the boron and / or phosphorus content is 15–40 wt%; the transition metal content in the outer layer is 30 wt%–65 wt%, with the balance being oxygen. The transition metal oxides, transition metal borides, and transition metal boron-phosphorus co-doped compounds are all amorphous, and their morphology and size are not limited, and they can be granular, flake-like, or spherical. The transition metal element in the amorphous catalyst can be selected from at least two of Fe, Co, Ni, Ce, Cu, Mn, V, W, and Mo, preferably Ni and Co; more preferably, the mass ratio of Ni to Co is 2.5:(0.1~1). When the mass ratio of Ni to Co is too small, the performance degrades; when the mass ratio of Ni to Co is too large, the performance degrades, and only when the ratio is 2.5:0.5 is the performance optimal.

[0033] After electrochemical activation, the hydrogen evolution performance of the electrocatalyst is significantly improved. For example, the activated amorphous nickel-cobalt-boron catalyst can reach 500 mA cm⁻¹ with only 175 mV overpotential in a 1 mol / L potassium hydroxide solution. -2 Therefore, the amorphous catalyst preparation method of the present invention is simple, has wide material applicability, and low cost, and has industrial practical value in the fields of water electrolysis and electrocatalysis.

[0034] Compared with hydrogen evolution catalysts containing noble metals, the amorphous reconstructed hydrogen evolution catalyst of the present invention exhibits superior HER catalytic activity without the presence of noble metals, and effectively maintains excellent stability of the catalyst during the HER reaction through the synergistic effect between the inner and outer layers.

[0035] The preparation and activation method of this invention is simple to operate, has a short preparation cycle, and is widely applicable to most amorphous catalysts (such as borides, phosphides, or boron-phosphorus compounds). Furthermore, this activation method can improve performance based on two aspects: firstly, it increases the density of active sites in the electrocatalyst after undergoing an electrochemical process; secondly, it changes the composition and electronic structure of the catalyst during the reconstruction process, thereby improving the intrinsic catalytic activity of the electrocatalyst. The nanosheet-like structure formed on the catalyst surface has good gas-repellent properties, which is more conducive to the exposure of catalytic active sites and improves gas-liquid mass transfer efficiency. The modified electrocatalyst obtained by this method can operate efficiently and stably in industrial high-current environments. Therefore, this novel amorphous catalyst and its universal preparation and activation method have important application value for the development of water electrolysis catalysts. The following exemplarily illustrates the preparation method of the amorphous reconstructed hydrogen evolution catalyst provided by this invention.

[0036] A chemical plating solution of a certain concentration is prepared by mixing transition metal salts, stabilizers, complexing agents, and reducing agents according to the elemental composition ratio of the amorphous reconstruction hydrogen evolution catalyst. The chemical plating solution consists of transition metal salts, stabilizers, complexing agents, reducing agents, and solvents. Specifically, the transition metal salt cation is selected from at least two of nickel, cobalt, iron, cerium, copper, manganese, vanadium, tungsten, and molybdenum; the stabilizer is selected from at least one of ethylenediamine, phosphoric acid, citric acid, carbonic acid, and acetic acid; the complexing agent is selected from at least one of hydroxides, citrates, pyrophosphates, thiosulfates, and sulfites; the reducing agent is selected from at least one of sodium borohydride, DMAB, and hydrazine hydrate; the concentration of the transition metal salt is 1–100 g / L; the solvent is water; and the pH value of the chemical plating solution is 6–10.

[0037] In this invention, the transition metal must be selected from at least two of nickel, cobalt, iron, cerium, copper, manganese, vanadium, tungsten, and molybdenum because amorphous catalysts prepared from single transition metal elements can also form a heterogeneous structure with inner and outer layers after electrochemical reduction. However, unlike amorphous catalysts formed from single transition metal elements, the outer oxide layer cannot be effectively maintained during subsequent stability tests, leading to a significant decrease in catalytic activity due to the reduction of the outer oxide layer. Therefore, selecting binary or multi-component transition metals can effectively maintain the stability of the heterogeneous catalyst in the later stages.

[0038] The substrate of the supported catalyst (such as nickel foam, sponge, filter paper, etc.) is pretreated with water, ethanol or acetone as a solution to remove surface impurities.

[0039] The pretreated nickel foam substrate was immersed in a prepared chemical plating solution and reacted at a temperature of 10–80°C for 0.5–12 h. The sample was then washed with deionized water and dried to obtain the amorphous catalyst.

[0040] The obtained amorphous catalyst was electrochemically activated to obtain the amorphous hydrogen evolution remodeling catalyst.

[0041] In an optional embodiment, the electrochemical activation is performed by multiple cyclic voltammetry or linear scan method tests. The parameters for the electrochemical activation may include: the activation solution is an alkaline solution with a concentration of 0.1–10 M, the test voltage is -1.5 V to -0.7 V, and the number of tests is 1–10. Preferably, the activation solution is a KOH solution with a concentration of 0.1–10 M or a NaOH solution with a concentration of 0.1–10 M; and the activation voltage is -1.5 V to -0.7 V.

[0042] In this invention, the amorphous reconstructed hydrogen evolution catalyst is used in hydrogen evolution with a working current density of 10–2500 mA / cm². -2 The electrolyte can be a 0.1–10 M NaOH or KOH alkaline solution.

[0043] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0044] Example 1 (Amorphous Ni) 2.5 Co 0.5 Preparation of catalyst B)

[0045] In Example 1, amorphous Ni 2.5 Co 0.5 The preparation method of catalyst B includes: washing nickel foam with water, ethanol, and hydrochloric acid, then placing it in a chemical plating solution and reacting it at 40°C for 2 hours to complete the treatment. After removing the electrode, washing it with water and drying it, amorphous Ni is obtained. 2.5 Co 0.5 Catalyst B. In the electroless plating solution, the mass ratio of transition metal salt (complexing agent (thiosulfate) + stabilizer (citric acid) + reducing agent (DMAB)) to water is 1:6:200, wherein the mass ratio of metallic nickel to metallic cobalt is 2.5:0.5. Subsequently, cyclic voltammetry is used to investigate the plating of amorphous Ni. 2.5 Co 0.5 Activation treatment of electrocatalyst B: Using KOH (1 mol / L) as the electrolyte solution, a graphite carbon rod as the counter electrode, and mercury / mercury oxide as the reference electrode, the prepared catalytic electrode was used as the working electrode, with a scanning voltage of -1.5V to -0.7V. Amorphous Ni 2.5 Co0.5 After seven cycles of cyclic voltammetry testing, catalyst B was found to be a highly active heterostructure catalyst.

[0046] The heterostructure catalyst obtained in Example 1 has an inner alloy layer that can effectively maintain the stability of the outer oxide layer, thereby continuously catalyzing the hydrogen evolution reaction and effectively improving the catalyst stability.

[0047] Evaluation criteria: The performance of the obtained amorphous reconstructed hydrogen evolution catalyst was tested using a three-electrode system. KOH (1 mol / L) was used as the electrolyte solution, graphite carbon rod as the counter electrode, mercury / mercuric oxide as the reference electrode, and the prepared catalytic electrode as the working electrode. The scanning voltage was -1.5V to -0.7V. The catalyst composition and evaluation results are shown in Tables 2 and 3.

[0048] Example 2 (Amorphous Ni) 2.5 Co 0.1 Preparation of catalyst B)

[0049] In this embodiment 2, amorphous Ni 2.5 Co 0.1 The preparation process of catalyst B is the same as in Example 1, except that the mass ratio of nickel to cobalt is 2.5:0.1. All other steps are the same as in Example 1. The evaluation conditions are the same as in Example 1. The catalyst composition and evaluation results are shown in Tables 2 and 3.

[0050] Example 3 (Amorphous Ni) 2.5 Co 0.3 Preparation of catalyst B)

[0051] In Example 3, amorphous Ni 2.5 Co 0.3 The preparation process of catalyst B is the same as in Example 1, except that the mass ratio of nickel to cobalt is 2.5:0.3. All other steps are the same as in Example 1. The evaluation conditions are the same as in Example 1. The catalyst composition and evaluation results are shown in Tables 2 and 3.

[0052] Example 4 (Amorphous Ni) 2.5 Co 0.7 Preparation of catalyst B)

[0053] In Example 4, amorphous Ni 2.5 Co 0.7 The preparation process of catalyst B is the same as in Example 1, except that the mass ratio of nickel to cobalt is 2.5:0.7. All other steps are the same as in Example 1. The evaluation conditions are the same as in Example 1. The catalyst composition and evaluation results are shown in Tables 2 and 3.

[0054] Example 5 (Amorphous Ni) 2.5 Co 0.5Preparation of BP catalysts

[0055] In Example 5, amorphous Ni 2.5 Co 0.5 The preparation process of the BP catalyst was the same as in Example 1, except that in the electroless plating solution, the mass ratio of metal salt:(complexing agent (thiosulfate) + stabilizer (citric acid) + reducing agent (DMAB and sodium hypophosphite)):water was 1:6:200, and the mass ratio of nickel to cobalt was 2.5:0.5. Other steps were the same as in Example 1. The evaluation conditions were the same as in Example 1, and the catalyst composition and evaluation results are shown in Tables 2 and 3.

[0056] Comparative Example 1 (Preparation of Amorphous CoB Catalyst)

[0057] The preparation process of the amorphous CoB catalyst in Comparative Example 1 was the same as in Example 1, except that the transition metal was only cobalt. Other steps were the same as in Example 1. The evaluation conditions were the same as in Example 1, and the catalyst composition and evaluation results are shown in Tables 2 and 3.

[0058] Comparative Example 2 (Preparation of Amorphous NiB Catalyst)

[0059] The preparation process of the amorphous NiB catalyst in Comparative Example 2 was the same as in Example 1, except that the transition metal was only nickel. Other steps were the same as in Example 1. The evaluation conditions were the same as in Example 1, and the catalyst composition and evaluation results are shown in Tables 2 and 3.

[0060] Table 1 lists the preparation parameters of the amorphous reconstructed hydrogen evolution catalysts in Examples 1-5 and Comparative Examples 1-2 of this invention: .

[0061] Table 2 shows the elemental content and composition of the surface and inner layers of different amorphous reconstructed hydrogen evolution catalysts obtained in the examples and comparative examples: .

[0062] Table 3 shows the amorphous reconstructed hydrogen evolution catalysts obtained in Examples 1-5 and Comparative Examples 1-2, and their hydrogen evolution performance evaluation results. .

[0063] Table 3 shows that as the nickel:cobalt mass ratio decreases, the overpotential first decreases and then increases, reaching its minimum when the nickel:cobalt mass ratio is 2.5:0.5. Furthermore, when the amorphous catalyst is a nickel-cobalt-boron-phosphorus catalyst with a nickel:cobalt mass ratio of 2.5:0.5, the overpotential is the lowest, requiring only 175 mV to reach 500 mA cm⁻¹. -2The catalytic activity reached its optimal level. Moreover, the overpotentials of the activated binary transition metal catalysts were all lower than those of the single transition metal catalysts, indicating that the binary transition metal catalysts exhibited a more significant reconstruction effect.

[0064] Figure 1 Ni prepared by electroless plating 2.5 Co 0.5 Scanning electron microscope (SEM) image of the NiCoB amorphous catalyst. As shown in the image, the original NiCoB alloy coating has a smooth surface and is composed of micron-sized cellular particles.

[0065] Figure 2 Ni after activation 2.5 Co 0.5 Scanning electron microscope (SEM) image of the amorphous catalyst B. As shown in the image, after activation treatment, the catalyst surface no longer appears as flat and smooth as the original material, but shows some tiny nanosheets and nanopores, indicating that catalyst morphology reconstruction occurred during the HER process.

[0066] Figure 3 For Ni 2.5 Co 0.5 Test results of hydrogen evolution performance of B / NF electrode before and after activation. As shown in the figure, Ni... 2.5 Co 0.5 The HER overpotential of B / NF showed a clear and gradually decreasing trend after 7 LSV cycles until it reached a steady state, indicating that the synthesized alloy catalyst undergoes an activation process during the HER process. Specifically, at a current density of 300 mA cm⁻¹ -2 At that time, 300mA cm can be clearly observed. -2 The overpotential at the point decreased from 290mV to 190mV.

[0067] Figure 4 For Ni 2.5 Co 0.5 Test results of hydrogen evolution stability of B / NF electrode under high current density. As shown in the figure, Ni... 2.5 Co 0.5 The B / NF electrode maintains good hydrogen evolution stability even at high current densities. This is mainly because the catalyst exhibits a two-layer heterogeneous structure after electrochemical reconstruction: an outer layer of cobalt oxide and an inner layer of nickel-cobalt-boron alloy. The inner nickel-cobalt-boron alloy effectively transfers electrons from the outer layer, keeping the outer cobalt oxide in an oxidized state and preventing excessive reduction, thus maintaining the catalyst's catalytic activity. In contrast, the oxides formed during surface reconstruction in monolithic transition metal catalysts are easily over-reduced during long-term hydrogen evolution reactions, leading to a significant decrease in catalytic activity. Therefore, binary transition metal catalysts can maintain more stable catalytic activity over a longer period.

[0068] Figure 5For different proportions of Ni x Co y The hydrogen evolution performance test results of electrode B. As shown in the figure, the overpotential is lowest when the mass ratio of nickel to cobalt is 2.5:0.5, indicating that the catalyst after electrochemical reconstruction can exhibit the best catalytic activity.

[0069] Figure 6 For Ni 2.5 Co 0.5 The results of hydrogen evolution performance tests of the BP electrode at 25℃ and 60℃ are shown in the figure. As can be seen from the figure, this reconstructed catalyst can be used not only at room temperature, but also exhibits excellent catalytic activity in harsh high-temperature environments.

Claims

1. An amorphous restructured hydrogen evolution catalyst, characterized by, The amorphous restructuring hydrogen evolution catalyst is a heterogeneous structure, the surface layer of which is a transition metal oxide, and the inner layer of which is a transition metal boride or a transition metal boron-phosphorus co-doped compound; the transition metal oxide, the transition metal boride and the transition metal boron-phosphorus co-doped compound are all amorphous; the transition metal in the amorphous restructuring hydrogen evolution catalyst is at least two of Fe, Co, Ni, Ce, Cu, Mn, V, W and Mo.

2. The amorphous restructured hydrogen evolution catalyst of claim 1, wherein, The transition metal oxide is in a nanosheet structure; preferably, the size of the transition metal oxide is 50-100 nm; The transition metal oxide is cobalt oxide; The transition metal boride is NiFeB or / and NiCoB; The transition metal boron-phosphorus co-doped compound is at least one of NiCoBP, NiFeBP, NiFeCoBP, NiBP and NiCoBP.

3. The amorphous restructured hydrogen evolution catalyst according to claim 1 or 2, characterized in that, In the surface layer of the amorphous restructuring hydrogen evolution catalyst, the content of the transition metal is 30wt%-65wt%, and the balance is oxygen element; In the inner layer of the amorphous restructuring hydrogen evolution catalyst, the content of the transition metal is 60-85wt%, and the content of boron or / and phosphorus is 15-40wt%.

4. A method for preparing an amorphous restructured hydrogen evolution catalyst according to any one of claims 1 to 3, characterized in that, The method comprises: (1) mixing a transition metal salt, a stabilizer, a complexing agent, a reducing agent and a solvent to obtain a chemical plating solution; (2) immersing a substrate in the obtained chemical plating solution to react at a temperature of 10-80℃ for 0.5-12h, and then washing and drying to obtain an amorphous catalyst; (3) electrochemically activating the obtained amorphous catalyst to obtain the amorphous restructuring hydrogen evolution catalyst; wherein the parameters of the electrochemical activation include: the activation solution is an alkali solution with a concentration of 0.1-10M; the activation voltage is-4.0V--0.2V; preferably, the activation solution is a KOH solution with a concentration of 0.1-10M or a NaOH solution with a concentration of 0.1-10M; and the activation voltage is-1.5V--0.7V.

5. The preparation method according to claim 4, characterized in that, The metal cation in the transition metal salt is at least one of Fe, Co, Ni, Ce, Cu, Mn, V, W and Mo; The stabilizer is at least one of ethylenediamine, phosphoric acid, citric acid, carbonic acid and acetic acid; The complexing agent is at least one of hydroxide, citrate, pyrophosphate, thiosulfate and sulfite; The reducing agent is at least one of sodium borohydride, DMAB and hydrazine hydrate.

6. The production method according to claim 4 or 5, characterized by, The pH value of the chemical plating solution is 2-14; The concentration of the transition metal salt in the chemical plating solution is 1-100g / L; The concentration of the stabilizer in the chemical plating solution is 1-25g / L; The concentration of the complexing agent in the chemical plating solution is 1-50g / L; The concentration of the reducing agent in the chemical plating solution is 1-25g / L.

7. The production method according to any one of claims 4 to 6, characterized by, Water, ethanol or acetone is used as a washing liquid to clean the substrate to remove surface impurities; the substrate is a conductive substrate or an insulating substrate; The conductive substrate is preferably a metal substrate, more preferably a foam metal substrate, and most preferably a foam nickel substrate; The insulating substrate is sponge, filter paper, carbon felt or graphite paper.

8. The production method according to any one of claims 4 to 7, characterized by, The amorphous catalyst is an amorphous structure composed of amorphous substances; the amorphous substances are transition metal borides or transition metal boron-phosphorus co-doped compounds; the amorphous substances are at least one of NiFeB, NiCoB, NiCoBP, NiFeBP and NiFeCoBP.

9. The production method according to any one of claims 4 to 8, characterized by, The electrochemical activation is cyclic voltammetry or linear sweep method; preferably, the electrochemical activation is cyclic voltammetry; the parameters of the cyclic voltammetry include: the activation solution is a KOH solution with a concentration of 0.1-10 M or a NaOH solution with a concentration of 0.1-10 M; the activation voltage is-1.5 V to-0.7 V.

10. A modified matrix characterized in that, The application further provides a preparation method of the amorphous restructured hydrogen evolution catalyst, comprising the following steps: A substrate and an amorphous restructured hydrogen evolution catalyst loaded in situ on the substrate; the substrate is a conductive substrate or an insulating substrate; Preferably, the conductive substrate is a metal substrate, more preferably a foam metal substrate, and most preferably a foam nickel substrate; Preferably, the insulating substrate is a sponge, filter paper, carbon felt or graphite paper.

11. Use of the amorphous restructured hydrogen evolution catalyst according to any one of claims 1 to 3 and the modified metal substrate according to claim 10 in an electrocatalytic hydrogen evolution reaction, characterized in that, The modified amorphous restructured hydrogen evolution catalyst electrode is used as a working electrode in an electrolyte, and shows excellent hydrogen evolution catalytic performance under a working current density of 10-2500 mAcm -2 . Preferably, the electrolyte is an alkali solution with a concentration of 0.1-10 M; more preferably, the electrolyte is a NaOH solution with a concentration of 0.1-10 M or a KOH solution with a concentration of 0.1-10 M; Preferably, the counter electrode is a graphite carbon rod; and the reference electrode is mercury / mercury oxide.

Images