A nano-catalyst, a preparation method and application thereof

Abstract

The present application relates to the technical field of nanocomposite catalyst preparation, and particularly relates to a kind of nanometer catalyst and its preparation method and application.A kind of nanometer catalyst, the nanometer catalyst is Fe-Si-B base alloy doped with transition metal, its general chemical formula is Fe 75‑ x M x Si 12.5 B 12.5 ;x is 2-10;Wherein, M is selected from transition metal Co or Ni.The nanometer catalyst prepared by the preparation method of the present application overcomes the problem of low electrocatalytic activity and stability of NS-Fe 75 Si 12.5 B 12.5 In addition, the preparation method of the present application is simple, and the repeatability is high, without relying on nickel foam substrate, and the nanometer catalyst is self-supporting, and is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanocomposite catalyst preparation, and particularly relates to a nanocatalyst and a preparation method and application thereof. BACKGROUND

[0002] Element doping is an important research direction in the field of electrocatalysis, and currently, noble metals (such as Pt) are considered to be the most active hydrogen evolution reaction catalysts to date, but due to their high price and scarcity, they hinder their wide application. In order to overcome this challenge, researchers try to improve the performance of the catalyst by doping other elements.

[0003] However, the existing NS-Fe 75 Si 12.5 B 12.5 has low electrocatalytic activity and stability, which is difficult to meet the actual demand. The hydrothermally synthesized catalyst based on a nickel foam substrate has insufficient self-supporting performance, which restricts its industrial application potential. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a nanocatalyst and a preparation method and application thereof. The present application provides a nanocatalyst which is a transition metal-doped Fe-Si-B-based alloy, and its chemical general formula is Fe 75- x M x Si 12.5 B 12.5 , and x is 2-10; wherein M is selected from transition metals Co or Ni. The nanocatalyst of the present application has a high specific surface area, a porous structure and excellent electrocatalytic performance, overcoming the problem that the existing NS-Fe 75 Si 12.5 B 12.5 has low electrocatalytic activity and stability, which is difficult to meet the actual demand. In addition, the nanocatalyst of the present application has excellent self-supporting performance and is suitable for large-scale production.

[0005] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0006] The first object of the present application is to provide a nanocatalyst which is a transition metal-doped Fe-Si-B-based alloy, and its chemical general formula is Fe 75-x M x Si 12.5 B 12.5 ; x is 2-10; wherein M is selected from transition metals Co or Ni, and X represents the atomic proportion of Co or Ni.

[0007] Preferably, the surface of the nanocatalyst is in a lamellar structure, the depth of the lamellar structure is in nanometer size, the lamellar structure has high specific surface area and can expose more active sites.

[0008] Preferably, when M is transition metal Co, the nanocatalyst is Fe 73 Co2Si 12.5 B 12.5 , Fe 70 Co5Si 12.5 B 12.5 , Fe 67 Co8Si 12.5 B 12.5 or Fe 65 Co 10 Si 12.5 B 12.5 .

[0009] Preferably, when M is transition metal Ni, the nanocatalyst is Fe 73 Ni2Si 12.5 B 12.5 , Fe 70 Ni5Si 12.5 B 12.5 , Fe 67 Ni8Si 12.5 B 12.5 or Fe 65 Ni 10 Si 12.5 B 12.5 .

[0010] A second object of the present application is to provide a preparation method of the nanocatalyst, comprising the following steps:

[0011] S1, weighing FeB, FeSi, pure Fe, Co or Ni and mixing to obtain a mixture according to the general formula Fe 75-x M x Si 12.5 B 12.5 , M is transition metal Co or Ni; wherein x is 2-10.

[0012] S2, subjecting the mixture to smelting treatment to obtain a Fe-Si-B-based alloy doped with transition metal.

[0013] S3, subjecting the Fe-Si-B-based alloy doped with transition metal to dealloying corrosion treatment to corrode off Si atoms and part of B atoms on the surface of the Fe-Si-B-based alloy doped with transition metal, so that the surface presents a lamellar structure, and then washing and drying to obtain the nanocatalyst.

[0014] Preferably, the conditions of the dealloying corrosion treatment are: corrosion in a strong alkali solution of 0.5 mol / L to 4 mol / L for 2 h to 3 h.

[0015] Preferably, the strong alkali solution is selected from a KOH solution or a NaOH solution.

[0016] Preferably, the conditions of the smelting treatment are: smelting at 1800 DEG C to 2200 DEG C for 5 min to 10 min.

[0017] A third object of the present application is to provide the use of the above-mentioned nano-catalyst in the preparation of an electrolytic water hydrogen evolution catalyst.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. The present application provides a nano-catalyst, which is a transition metal-doped Fe-Si-B-based alloy with a chemical formula of Fe 75-x M x Si 12.5 B 12.5 , and x is 2 to 10; wherein M is selected from transition metals Co or Ni.

[0020] 2. The present application provides a preparation method of a nano-catalyst, which is a transition metal-doped Fe-Si-B-based alloy with a chemical formula of Fe 75-x M x Si 12.5 B 12.5 , M is a transition metal Co or Ni, FeB, FeSi and Fe, and Co or Ni are weighed and mixed to obtain a mixture; wherein x is 2 to 10; the mixture is subjected to a smelting treatment to obtain a transition metal-doped Fe-Si-B-based alloy; the transition metal-doped Fe-Si-B-based alloy is subjected to a dealloying corrosion treatment to corrode off Si atoms and part of B atoms on the surface of the transition metal-doped Fe-Si-B-based alloy, and the surface presents a lamellar structure; after washing and drying, a nano-catalyst is obtained.

[0021] 3. The nano-catalyst of the present application is used for an electrolytic water hydrogen evolution reaction, and compared with Fe 75 Si12.5 B 12.5 and NS-Fe 75 Si 12.5 B 12.5 The Co or Ni-doped nanocatalyst provided by the present application reduces the hydrogen evolution overpotential to 175.1 mV and 168 mV (the undoped system is ≥ 214 mV) at a current density of 10 mA / cm 2 The Tafel slope is significantly optimized to 134 mV / dec and 158 mV / dec (the undoped system is ≥ 210 mV / dec), the charge transfer resistance of the optimal Co-doped nanocatalyst is as low as 2.265 Ω, and the charge transfer resistance of the optimal Ni-doped nanocatalyst is as low as 2.515 Ω (the undoped system is 3.67 Ω). At the same time, the introduction of the nanosheet layered porous structure significantly improves the electrochemical active surface area of the nanocatalyst of the present application, and the nanocatalyst of the present application can be stably operated for 15 h to 20 h at a current density of 50 mA / cm 2 The synergistic optimization of the active site density and the electron transfer efficiency significantly enhances the water electrolysis hydrogen evolution kinetics and durability of the nanocatalyst of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 XRD patterns of Fe 65 Co 10 Si 12.5 B 12.5 and NS-Fe 65 Co 10 Si 12.5 B 12.5 of Example 4 75 Si 12.5 B 12.5 .

[0023] Figure 2 XRD patterns of Fe 65 Co 10 Si 12.5 B 12.5 and NS-Fe 65 Co 10 Si 12.5 B 12.5 Scanning electron microscope images and EDS spectra of Fe 65 Co 10 Si 12.5 B 12.5 × 5000, b is NS-Fe 65 Co 10 Si 12.5 B 12.5 × 5000, c is NS-Fe 65 Co10 Si 12.5 B 12.5 SEM images of NS-Fe of Example 4 at 7000 times magnification, d is NS-Fe 65 Co 10 Si 12.5 B 12.5 EDS spectra of NS-Fe of Example 4.

[0024] Figure 3 SEM images of NS-Fe of Comparative Example 1, (a) is a SEM image, (b) is an EDS spectrum of Fe, (c) is an EDS spectrum of B. 75 Si 12.5 B 12.5 EDS spectra of NS-Fe of Example 4, (a) is a SEM image, (b) is an EDS spectrum of Fe, (c) is an EDS spectrum of B.

[0025] Figure 4 SEM images of NS-Fe of Example 4 at 7000 times magnification, d is NS-Fe 65 Co 10 Si 12.5 B 12.5 XPS spectra of NS-Fe of Example 4, a is NS-Fe 65 Co 10 Si 12.5 B 12.5 , b is Co 2p, c is Fe 2p, d is Si 2p, e is O 1s.

[0026] Figure 5 SEM images of NS-Fe of Example 4 at 7000 times magnification, d is NS-Fe 75 Si 12.5 B 12.5 Electrocatalytic performance test graphs of NS-Fe of Example 4 and Comparative Example 1, a is a comparison graph of LSV of NS-Fe of Example 1-4, b is a comparison graph of LSV of NS-Fe of Example 4 and Comparative Example 1 75 Si 12.5 B 12.5 LSV comparison graphs of NS-Fe of Example 4 and Comparative Example 1, c is an overpotential graph, d is a Tafel slope graph, e is an impedance graph, f is C dl graph, g is a local magnification graph in the potential range of -0.1V to -0.4V in the a graph, h is a local magnification of the high frequency region of the AC impedance spectrum in the e graph.

[0027] Figure 6 SEM images of NS-Fe of Example 4 at 7000 times magnification, d is NS-Fe 65 Co 10 Si 12.5 B 12.5 Stability test graphs of NS-Fe of Example 4, a is a comparison graph of linear sweep voltammetry before and after 1000 cycles, b is a current density vs. time curve graph at a potential of 269mV.

[0028] Figure 7 Fe of Example 5 73 Ni2Si 12.5 B 12.5 Fe of Comparative Example 1 75 Si 12.5 B 12.5 X-ray diffraction pattern of Fe of Comparative Example 1

[0029] Figure 8 Fe of Comparative Example 1 75 Si 12.5 B 12.5 NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 Scanning electron microscope images of Fe of Comparative Example 1 75 Si 12.5 B 12.5 at a magnification of 5000 times, b is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 at a magnification of 5000 times, c is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 at a magnification of 2000 times, d is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 at a magnification of 10000 times, e is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 at a magnification of 20000 times, f is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 EDS spectrum of NS-Fe of Example 5

[0030] Figure 9 X-ray photoelectron spectrum of NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 a is NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 b is Ni 2p, c is Fe 2p, d is Si 2p, e is O 1s

[0031] Figure 10 Nanocatalyst of Example 5 to Example 8 and NS-Fe of Comparative Example 1 75 Si 12.5 B 12.5Figure 1 is a comparison chart of LSV of the electrocatalytic performance test of the Fe 73 Ni2Si 12.5 B 12.5 and NS-Fe 73 Ni2Si 12.5 B 12.5 and NS-Fe of Comparative Example 1 75 Si 12.5 B 12.5 and NS-Fe 75 Si 12.5 B 12.5 of the Fe C dl Figure.

[0032] Figure 11 of the NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 of the NS-Fe of Comparative Example 1 75 Si 12.5 B 12.5 of the NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 of the NS-Fe of Comparative Example 1 75 Si 12.5 B 12.5 of the NS-Fe of Example 5 73 Ni2Si 12.5 B 12.5 of the NS-Fe of Example 5 DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be described clearly and completely below in combination with the data in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] It should be noted that the professional terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the scope of protection of the present application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present application can be purchased from the market or prepared by the existing method.

[0035] At present, the existing NS-Fe 75 Si 12.5 B 12.5 The electrocatalytic activity and stability are low, and it is difficult to meet the actual demand. The hydrothermal synthesis catalyst based on the nickel foam substrate has insufficient self-supporting performance, which restricts its industrial application potential.

[0036] In view of the problems existing in the prior art, the present application provides a kind of nano catalyst, the nano catalyst is Fe-Si-B based alloy doped with transition metal, its chemical general formula is Fe 75-x M x Si 12.5 B 12.5 And x is 2-10;Wherein, M is selected from transition metal Co or Ni.

[0037] The present application reconstructs the electronic structure of Fe-Si-B alloy by doping Co or Ni, at the same time, the nanosheet layered porous structure formed by dealloying corrosion treatment significantly increases the specific surface area, exposes more active sites, and synergistically improves the catalytic activity and stability, overcoming the problem that the electrocatalytic activity and stability of the prior art pure FeSiB are low and difficult to meet the actual demand.

[0038] The present application adopts arc melting method combined with dealloying corrosion treatment, which avoids the complex process of traditional hydrothermal method or molten salt method. By adjusting the melting parameters and corrosion conditions, the composition and structure of the nano catalyst are precisely controlled. The preparation method of the present application is simple and has high repeatability, does not need to rely on nickel foam substrate, and the obtained nano catalyst has excellent self-supporting performance and is suitable for large-scale production.

[0039] The performance of the nano catalyst prepared by the present application is better than that of the noble metal-based catalyst, overcoming the problem that the noble metal such as platinum is used in the preparation of the existing electrolytic water hydrogen evolution reaction catalyst, and reducing the cost.

[0040] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific embodiments:

[0041] Example 1

[0042] A preparation method of a nano catalyst, comprising the following steps:

[0043] S1, according to the chemical general formula Fe 75-x Co x Si 12.5 B 12.5FeB, FeSi, pure Fe and Co are weighed, wherein x is 2; that is, FeB (wherein the proportion of B is 19.37%), FeSi (wherein the proportion of Si is 75%), pure Fe and Co are weighed according to the atomic proportions of Fe, B, Si and Co being 73:12.5:12.5:2, the total mass is 20g, and mixing is performed, to obtain a mixed material.

[0044] S2, the mixed material is placed into an electric arc smelting furnace, argon is introduced into the furnace to create a protective atmosphere. High temperature is generated by electric arc discharge to melt the mixed material, and the mixed material is fully mixed by magnetic stirring. During the smelting process, the front and back of the mixed material are repeatedly smelted three times, and each smelting is accompanied by three magnetic stirring operations; after the smelting is completed, the operation mode of arc smelting suction casting is adopted to prepare the molten raw material into a cylindrical rod with a diameter of 6, and then naturally cooled to room temperature, to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 73 Co2Si 12.5 B 12.5 .

[0045] S3, the transition metal-doped Fe-Si-B-based alloy after cooling is cut by using a wire cutting machine, to obtain small iron pieces with a thickness of 0.5mm, a length and a width of 5mm. Then, it is placed in a 2mol / L KOH solution for 3h of dealloying corrosion treatment, to obtain a nano catalyst, denoted as NS-Fe 73 Co2Si 12.5 B 12.5 .

[0046] Example 2

[0047] A preparation method of a nano catalyst is the same as that of Example 1, and the difference is that x in S1 is replaced by 5, including the following steps:

[0048] S1, Fe 75-x Co x Si 12.5 B 12.5 FeB, FeSi, pure Fe and Co are weighed, wherein x is 5; that is, FeB (wherein the proportion of B is 19.37%), FeSi (wherein the proportion of Si is 75%), pure Fe and Co are weighed according to the atomic proportions of Fe, B, Si and Co being 70:12.5:12.5:5, the total mass is 20g, and mixing is performed, to obtain a mixed material.

[0049] S2, put the mixed material into an electric arc melting furnace, and introduce argon into the furnace to create a protective atmosphere. Use electric arc discharge to generate high temperature to melt the mixed material, and use magnetic stirring to fully mix the mixed material. During the melting process, the front and back of the mixed material are repeatedly melted three times, each time accompanied by three magnetic stirring operations; after the melting is completed, the molten raw material is made into a cylindrical rod with a diameter of 6 using the electric arc melting suction casting operation, and then naturally cooled to room temperature to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 70 Co5Si 12.5 B 12.5 .

[0050] S3, use a wire cutting machine to cut the cooled transition metal-doped Fe-Si-B-based alloy to obtain small iron pieces with a thickness of 0.5 mm, a length of 5 mm, and a width of 5 mm. Then place it in a 2 mol / L KOH solution and dealloying corrosion treatment for 3 hours to obtain a nano-catalyst, denoted as NS-Fe 70 Co5Si 12.5 B 12.5 .

[0051] Example 3

[0052] A method for preparing a nano-catalyst, which is the same as the preparation method of Example 1, except that x in S1 is replaced by 8, comprising the following steps:

[0053] S1, according to the chemical formula Fe 75-x Co x Si 12.5 B 12.5 Weigh FeB, FeSi, pure Fe and Co, wherein x is 8; that is, according to the atomic ratio of Fe, B, Si, and Co is 67:12.5:12.5:8, respectively weigh FeB (wherein B accounts for 19.37%), FeSi (wherein Si accounts for 75%), pure Fe and Co, the total mass is 20g, and mix to obtain a mixed material.

[0054] S2, put the mixed material into an electric arc melting furnace, and introduce argon into the furnace to create a protective atmosphere. Use electric arc discharge to generate high temperature to melt the mixed material, and use magnetic stirring to fully mix the mixed material. During the melting process, the front and back of the mixed material are repeatedly melted three times, each time accompanied by three magnetic stirring operations; after the melting is completed, the molten raw material is made into a cylindrical rod with a diameter of 6 using the electric arc melting suction casting operation, and then naturally cooled to room temperature to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 67 Co8Si 12.5 B 12.5 .

[0055] S3, using a wire cutting machine to cut the cooled transition metal doped Fe-Si-B based alloy, obtaining small iron pieces with a thickness of 0.5 mm, a length and a width of 5 mm. Then placed in a 2 mol / L KOH solution, dealloying corrosion treatment for 3 h, to obtain a nano catalyst, denoted as NS-Fe 67 Co8Si 12.5 B 12.5 .

[0056] Example 4

[0057] A method for preparing a nano catalyst, which is the same as the preparation method of Example 1, except that x in S1 is replaced by 10, comprising the following steps:

[0058] S1, according to the chemical formula Fe 75-x Co x Si 12.5 B 12.5 FeB, FeSi, pure Fe and Co are weighed, wherein x is 10; that is, according to the atomic ratio of Fe, B, Si and Co is 65:12.5:12.5:10, FeB (wherein B accounts for 19.37%), FeSi (wherein Si accounts for 75%), pure Fe and Co are weighed respectively, the total mass is 20g, and mixed to obtain a mixture.

[0059] S2, the mixture is placed in an arc melting furnace, and argon is introduced into the furnace to create a protective atmosphere. High temperature is generated by arc discharge to melt the mixture, and the mixture is fully mixed by magnetic stirring. During the melting process, the mixture is repeatedly melted on the front and back surfaces for three times, each time with three magnetic stirring operations; after the melting is completed, the operation mode of arc melting suction casting is adopted to prepare the molten raw material into a cylindrical rod with a diameter of 6, and then naturally cooled to room temperature to obtain a transition metal doped Fe-Si-B based alloy, denoted as Fe 65 Co 10 Si 12.5 B 12.5 .

[0060] S3, using a wire cutting machine to cut the cooled transition metal doped Fe-Si-B based alloy, obtaining small iron pieces with a thickness of 0.5 mm, a length and a width of 5 mm. Then placed in a 2 mol / L KOH solution, dealloying corrosion treatment for 3 h, to obtain a nano catalyst, denoted as NS-Fe 65 Co 10 Si 12.5 B 12.5 .

[0061] Example 5

[0062] A preparation method of a nano-catalyst, which is the same as the preparation method of Example 1, except that the Co atoms in S1 are replaced by Ni atoms, comprising the following steps:

[0063] S1, according to the chemical formula Fe 75-x Ni x Si 12.5 B 12.5 FeB, FeSi, pure Fe and Ni are weighed, wherein x is 2; that is, FeB (wherein B accounts for 19.37%), FeSi (wherein Si accounts for 75%), pure Fe and Ni are weighed according to the atomic ratio of Fe, B, Si and Ni being 73:12.5:12.5:2, the total mass is 20g, and mixed to obtain a mixture.

[0064] S2, the mixture is placed in an arc melting furnace, argon is introduced into the furnace to create a protective atmosphere. High temperature is generated by arc discharge to melt the mixture, and the mixture is fully mixed by magnetic stirring. During the melting process, the mixture is repeatedly melted on the front and back surfaces for three times, and each melting is accompanied by three magnetic stirring operations; after the melting is completed, the operation mode of arc melting suction casting is adopted to prepare the molten raw material into a cylindrical rod with a diameter of 6, and then naturally cooled to room temperature to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 73 Ni2Si 12.5 B 12.5 .

[0065] S3, the transition metal-doped Fe-Si-B-based alloy after cooling is cut by a wire cutting machine to obtain small iron pieces with a thickness of 0.5mm, a length and a width of 5mm. Then placed in a 2mol / L KOH solution for 3h of dealloying corrosion treatment to obtain a nano-catalyst, denoted as NS-Fe 73 Ni2Si 12.5 B 12.5 .

[0066] Example 6

[0067] A preparation method of a nano-catalyst, which is the same as the preparation method of Example 2, except that the Co atoms in S1 are replaced by Ni atoms, comprising the following steps:

[0068] S1, according to the chemical formula Fe 75-x Ni x Si 12.5 B 12.5FeB, FeSi, pure Fe and Ni are weighed, wherein x is 5; that is, FeB (wherein the proportion of B is 19.37%), FeSi (wherein the proportion of Si is 75%), pure Fe and Ni are weighed according to the atomic proportions of Fe, B, Si and Ni being 70:12.5:12.5:5, the total mass is 20g, and mixing is performed, to obtain a mixed material.

[0069] S2, the mixed material is placed into an electric arc smelting furnace, argon is introduced into the furnace to create a protective atmosphere. High temperature is generated by electric arc discharge to melt the mixed material, and the mixed material is fully mixed by magnetic stirring. During the smelting process, the front and back of the mixed material are repeatedly smelted three times, and each smelting is accompanied by three magnetic stirring operations; after the smelting is completed, the operation mode of arc smelting suction casting is adopted to prepare the molten raw material into a cylindrical rod with a diameter of 6, and then naturally cooled to room temperature, to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 70 Ni5Si 12.5 B 12.5 .

[0070] S3, the transition metal-doped Fe-Si-B-based alloy after cooling is cut by using a wire cutting machine, to obtain small iron pieces with a thickness of 0.5mm, a length and a width of 5mm. Then, it is placed in a 2mol / L KOH solution for 3h of dealloying corrosion treatment, to obtain a nano-catalyst, denoted as NS-Fe 70 Ni5Si 12.5 B 12.5 .

[0071] Example 7

[0072] A preparation method of a nano-catalyst is the same as that of Example 3, except that the Co atom in S1 is replaced by a Ni atom, comprising the following steps:

[0073] S1, Fe 75-x Ni x Si 12.5 B 12.5 FeB, FeSi, pure Fe and Ni are weighed, wherein x is 8; that is, FeB (wherein the proportion of B is 19.37%), FeSi (wherein the proportion of Si is 75%), pure Fe and Ni are weighed according to the atomic proportions of Fe, B, Si and Ni being 67:12.5:12.5:8, the total mass is 20g, and mixing is performed, to obtain a mixed material.

[0074] S2, put the mixed material into an arc melting furnace, and pass argon into the furnace to create a protective atmosphere. Use arc discharge to generate high temperature to melt the mixed material, and use magnetic stirring to fully mix the mixed material. During the melting process, repeatedly melt the front and back of the mixed material three times, each time accompanied by three magnetic stirring operations; after the melting is completed, use the arc melting suction casting operation to make the molten raw material into a φ6 cylindrical rod shape, and then naturally cool to room temperature to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe 67 Ni8Si 12.5 B 12.5 .

[0075] S3, use a wire cutting machine to cut the cooled transition metal-doped Fe-Si-B-based alloy to obtain small iron pieces with a thickness of 0.5 mm, a length and a width of 5 mm. Then place it in a 2 mol / L KOH solution and dealloying corrosion treatment for 3 h to obtain a nano catalyst, denoted as NS-Fe 67 Ni8Si 12.5 B 12.5 .

[0076] Example 8

[0077] A method for preparing a nano catalyst, which is the same as the preparation method of Example 4, except that the Co atoms in S1 are replaced by Ni atoms to obtain a nano catalyst, denoted as NS-Fe 65 Ni 10 Si 12.5 B 12.5 .

[0078] S1, according to the chemical formula Fe 75-x Ni x Si 12.5 B 12.5 Weigh FeB, FeSi, pure Fe and Ni, wherein x is 10; that is, according to the atomic ratio of Fe, B, Si and Ni is 65:12.5:12.5:10, respectively weigh FeB (wherein B accounts for 19.37%), FeSi (wherein Si accounts for 75%), pure Fe and Ni, the total mass is 20g, and mix to obtain a mixed material.

[0079] S2, put the mixed material into an arc melting furnace, and pass argon into the furnace to create a protective atmosphere. Use arc discharge to generate high temperature to melt the mixed material, and use magnetic stirring to fully mix the mixed material. During the melting process, repeatedly melt the front and back of the mixed material three times, each time accompanied by three magnetic stirring operations; after the melting is completed, use the arc melting suction casting operation to make the molten raw material into a φ6 cylindrical rod shape, and then naturally cool to room temperature to obtain a transition metal-doped Fe-Si-B-based alloy, denoted as Fe65 Ni 10 Si 12.5 B 12.5 ...

[0080] S3. The cooled Fe-Si-B based alloy doped with transition metal was cut using a wire EDM machine to obtain small iron sheets with a thickness of 0.5 mm and a length and width of 5 mm. These sheets were then placed in a 2 mol / L KOH solution for de-alloying corrosion treatment for 3 hours to obtain a nano-catalyst, denoted as NS-Fe. 65 Ni 10 Si 12.5 B 12.5 .

[0081] Comparative Example 1

[0082] A method for preparing a nanocatalyst includes the following steps:

[0083] S1, according to the general chemical formula Fe 75 Si 12.5 B 12.5 Weigh FeB, FeSi, and pure Fe; that is, weigh FeB (where B accounts for 19.37%), FeSi (where Si accounts for 75%), and pure Fe according to an atomic ratio of 75:12.5:12.5, with a total mass of 20g, and mix them to obtain a mixture.

[0084] S2. Place the mixture into an electric arc melting furnace and introduce argon gas to create a protective atmosphere. The high temperature generated by the electric arc discharge melts the mixture, and magnetic stirring ensures thorough mixing. During the melting process, the mixture is repeatedly melted on both sides three times, with each melting process accompanied by three magnetic stirring operations. After melting, an electric arc melting and casting method is used to form the molten material into φ6 cylindrical rods, which are then naturally cooled to room temperature to obtain Fe. 75 Si 12.5 B 12.5 .

[0085] S3. Use a wire EDM machine to process the cooled Fe... 75 Si 12.5 B 12.5 The iron was cut to obtain small iron sheets with a thickness of 0.5 mm and a length and width of 5 mm. These sheets were then placed in a 2 mol / L KOH solution for de-alloying etching treatment for 3 hours to obtain NS-Fe. 75 Si 12.5 B 12.5 .

[0086] Depend on Figure 1 The red rhomboid peaks represent NS-Fe. 65 Co 10 Si12.5 B 12.5 , pink diamond peak represents Fe 65 Co 10 Si 12.5 B 12.5 , blue diamond peak represents Fe 75 Si 12.5 B 12.5 . Among them, 2 θ peaks with angles of 44.675°, 65.026° and 82.339° correspond to (110), (200) and (211) crystal faces of Fe respectively; 2 θ peaks with angles of 45.047°, 65.603° and 79.730° correspond to (210), (310) and (123) crystal faces of FeSi respectively; 2 θ peaks with angles of 42.611°, 45.107°, 56.339° and 79.763° correspond to (002), (211), (202) and (330) crystal faces of Fe2B respectively. The diffraction peaks of FeSi and Fe2B are consistent with those of Fe 75 Si 12.5 B 12.5 , Fe 65 Co 10 Si 12.5 B 12.5 and NS-Fe 65 Co 10 Si 12.5 B 12.5 , the diffraction peaks of Co7Fe3 at 2 θ peaks with angles of 45.169°, 65.712° and 83.252° are (110), (200) and (211) respectively, which proves that the prepared Fe 65 Co 10 Si 12.5 B 12.5 contains Fe, Si, B and Co four elements, which corresponds to the EDS spectrum, and NS-Fe 65 Co 10 Si 12.5 B 12.5 is successfully synthesized.

[0087] Compared with Fe 75 Si 12.5 B 12.5 , the diffraction intensity of NS-Fe 65 Co 10 Si 12.5 B 12.5 is stronger, indicating that the doping of Co can effectively improve the Fe 75 Si 12.5 B 12.5crystallinity. Especially, the increase of Fe-Si phase crystallinity reflects the enhanced combination of Si and metal. The dealloyed NS-Fe 65 Co 10 Si 12.5 B 12.5 , Fe-Si phase disappears and Fe phase appears, which indicates that Si is dissolved in alkaline solution during the dealloying process. Compared with the un-etched Fe 65 Co 10 Si 12.5 B 12.5 The intensity of the diffraction peak at 42.611° is weakened, which indicates that part of B element is dissolved during the dealloying process.

[0088] The surface morphology of Fe 65 Co 10 Si 12.5 B 12.5 before and after dealloying was further observed by scanning electron microscope. It is observed from Fig. a and Fig. b of Figure 2 that after etching, NS-Fe 65 Co 10 Si 12.5 B 12.5 forms nanosheet structure on the surface, but part of the area is not completely etched. It is observed from Fig. c of Figure 2 that compared with the un-doped Co Fe 75 Si 12.5 B 12.5 , see Figure 3 , the surface of the nanometer porous structure is smaller and more.

[0089] It is observed from Fig. d of Figure 2 that the content distribution of Fe, Si, B and Co is consistent with the result of X-ray diffraction spectrum.

[0090] It is observed from Fig. a of Figure 4 that there are Fe, Co, Si and B on the surface of NS-Fe 65 Co 10 Si 12.5 B 12.5 , and the corresponding binding energy peaks are 787eV, 712eV, 180eV and 102eV respectively. It is observed from Fig. b of Figure 4 that the two peaks near 780.78eV and 795.98eV correspond to the 2p 3 / 2 and 2p 1 / 2 peaks of Co in oxidation state respectively; the two peaks near 785.18eV and 802.33eV correspond to the satellite peaks of Co 2+ . The intensity of the satellite peak of Co 2+ ion has approached the 2p3 / 2 The intensity of the Fe 2p peak indicates that NS-Fe 65 Co 10 Si 12.5 B 12.5 There is a large amount of +2 valence Co on the surface. From the c plot in FIG. 7, Figure 4 Fe 2p peak compared to NS-Fe 75 Si 12.5 B 12.5 , NS-Fe 65 Co 10 Si 12.5 B 12.5 There is still a small amount of Fe on the surface after dealloying 0 Fe 2p peak (706.03 eV), indicating that the Co doping intervention changes the valence state of Fe, and Fe atoms are less likely to be oxidized during the dealloying process.

[0091] From the d plot in FIG. 7, Figure 4 Fe 2p peak compared to NS-Fe 65 Co 10 Si 12.5 B 12.5 The Si and metal bond peak on the surface is enhanced, indicating that Co doping helps to bind Si and metal. From the e plot in FIG. 7, Figure 4 Fe 2p and Si 2p results, the intensity of the Si-O bond is enhanced and the intensity of the Fe-O bond is weakened after Co doping.

[0092] From the a plot in FIG. 7, Figure 5 The hydrogen evolution reaction overpotential decreases as the amount of Co doping increases, and NS-Fe 65 Co 10 Si 12.5 B 12.5 has the best hydrogen evolution reaction activity. NS-Fe 65 Co 10 Si 12.5 B 12.5 can reach a overpotential of 314.7 mV at a current density of 100 mA / cm 2 , which is much lower than NS-Fe 67 Co8Si 12.5 B 12.5 (348.7 mV), NS-Fe 70 Co5Si 12.5 B 12.5 (395.7 mV), and NS-Fe 73 Co2Si 12.5 B 12.5 (415.7 mV). Similarly, NS-Fe 65 Co 10 Si 12.5 B12.5 At 10mA / cm 2 The overpotential at the specified current density is 175.1 mV. This is due to the synergistic effect between Fe and Co ions. During the H2 evolution process in water electrolysis, the Co atoms in these Co-Fe groups act as reaction sites for the OH bond cleavage of water, while the Fe atoms serve as H2 evolution centers. Furthermore, the corroded surface has the largest specific surface area, exposing more active sites and exhibiting better hydrogen evolution reaction performance. Figure 5 Figure b shows that Co-doped NS-Fe 75 Si 12.5 B 12.5 Significantly better than undoped NS-Fe 75 Si 12.5 B 12.5 Performance has been greatly improved. Uncorroded Fe 65 Co 10 Si 12.5 B 12.5 With NS-Fe 75 Si 12.5 B 12.5 The performance is similar, but after 100mA / cm 2 Under current density conditions, uncorroded Fe 65 Co 10 Si 12.5 B 12.5 It has good performance. Figure 5 From graph c, we can see that at a current density of 10 mA / cm² 2 Below, NS-Fe 67 Co8Si 12.5 B 12.5 NS-Fe 70 Co5Si 12.5 B 12.5 NS-Fe 73 Co2Si 12.5 B 12.5 Fe 65 Co 10 Si 12.5 B 12.5 NS-Fe 75 Si 12.5 B 12.5 The overpotentials were 198.2mV, 211.1mV, 199.7mV, 215mV, and 214mV, respectively.

[0093] To further investigate the effect of Co doping on NS-Fe 75 Si 12.5 B 12.5 The influence of [the specific factor] will be revealed through Tafel analysis, which will elucidate the kinetics and reaction mechanism of the hydrogen evolution reaction. For example...Figure 5 NS-Fe 65 Co 10 Si 12.5 B 12.5 NS-Fe 67 Co8Si 12.5 B 12.5 NS-Fe 70 Co5Si 12.5 B 12.5 NS-Fe 73 Co2Si 12.5 B 12.5 Fe 65 Co 10 Si 12.5 B 12.5 Tafel slope of 134 mV / dec, 165 mV / dec, 212 mV / dec, 161 mV / dec, 210 mV / dec, respectively, which indicates that NS-Fe 65 Co 10 Si 12.5 B 12.5 is more conducive to improving the catalytic kinetics of hydrogen evolution reaction.

[0094] From e figure in Figure 5 NS-Fe 60 Co 10 Si 12.5 B 12.5 charge transfer resistance is the smallest, which is 2.265 Ω, less than NS-Fe 67 Co8Si 12.5 B 12.5 (2.709 Ω), NS-Fe 70 Co5Si 12.5 B 12.5 (2.961 Ω), NS-Fe 73 Co2Si 12.5 B 12.5 (2.843 Ω), Fe 60 Co 10 Si 12.5 B 12.5 (2.713 Ω) and NS-Fe 75 Si 12.5 B 12.5 (3.67 Ω). It shows that the transfer rate of electrons in NS-Fe 65 Co 10 Si 12.5 B 12.5 is improved, which confirms that the Co doping has superior electrocatalytic performance.

[0095] By obtaining the area of ​​the cyclic voltammetric characteristic curves at different rates in the non-Radida region and the slope of the straight line fitted by the scan rate, the bilayer specific capacitance of different materials can be obtained. C dl .like Figure 5 As shown in f, in a 1 mol / L KOH solution, at a voltage of 0.05 V, the linear relationship between current density difference and scan rate is observed for NS-Fe. 65 Co 10 Si 12.5 B 12.5 NS-Fe 67 Co8Si 12.5 B 12.5 NS-Fe 70 Co5Si 12.5 B 12.5 NS-Fe 73 Co2Si 12.5 B 12.5 Fe 65 Co 10 Si 12.5 B 12.5 The Cdl values ​​(corresponding ECSA values) were 0.342 mF / cm (8.55), 0.325 mF / cm (8.125), 0.283 mF / cm (7.075), 0.258 mF / cm (6.45), and 0.157 mF / cm (3.925), respectively. C dl The ECSA value gradually increases with increasing Co doping concentration. This is because Co doping improves the dispersibility of the nanocatalyst, resulting in finer nanocatalyst particles with a larger specific surface area. Furthermore, Co doping induces electronic effects, altering the electronic states of the FeSiB alloy and thus affecting its catalytic performance. In addition, the synergistic effect between Co and Fe, Si, and B leads to the formation of new active sites, increasing the electrochemical active area.

[0096] In addition, NS-Fe 65 Co 10 Si 12.5 B 12.5 It also exhibits excellent stability in the hydrogen evolution reaction. Figure 6 Figure a shows that after 1000 cycles, NS-Fe 65 Co 10 Si 12.5 B 12.5 The linear sweep voltammetric characteristic curve showed no significant change compared to before cycling, indicating good stability in the hydrogen evolution reaction. Figure 6 Figure b shows that after 15 hours of hydrogen evolution reaction, the hydrogen evolution reaction current density decreased to 81.9% of the initial value, indicating that the NS-Fe...65 Co 10 Si 12.5 B 12.5 It can stably carry out the hydrogen evolution reaction over a long period of time. Co doping improves NS-Fe 75 Si 12.5 B 12.5 Improving the crystallinity enhances the bonding of metal bonds and improves the lattice structure of nanocatalysts, which not only enhances the catalytic performance of nanocatalysts but also improves their stability.

[0097] like Figure 7 As shown, the green rhomboid peaks represent NS-Fe. 73 Ni2Si 12.5 B 12.5 The deep red rhomboid peak represents Fe 73 Ni2Si 12.5 B 12.5 The light blue rhomboid peaks represent Fe. 75 Si 12.5 B 12.5 Samples. Among them, 2 θ Three strong diffraction peaks exist at 45.22°, 65.38°, and 83.1°, corresponding to Fe... 0.95 Ni 0.05 (PDF#04-004-8515) and Fe(PDF#04-004-8514) crystal planes (110), (200) and (211), 2 θ The diffraction peaks at 42.527°, 45.043°, 49.71°, 50.436°, 56.244°, 56.912°, 79.533°, and 80.668° correspond to the (002), (121), (112), (022), (130), (132), (330), and (141) crystal planes of Fe2B (PDF#36-1332), respectively. θ The diffraction peaks at 45.047°, 65.603°, and 79.730° correspond to the (210), (310), and (123) crystal planes of FeSi (PDF#86-0792), respectively. The diffraction peaks of Fe2B and FeSi correspond to the Fe... 75 Si 12.5 B 12.5 Fe 73 Ni2Si 12.5 B 12.5 and NS-Fe 73 Ni2Si 12.5 B 12.5 The diffraction peaks are consistent, proving that NS-Fe 73 Ni2Si 12.5 B 12.5There are four elements of Fe, Ni, B and Si.

[0098] Compared with Fe 75 Si 12.5 B 12.5 , NS-Fe 73 Ni2Si 12.5 B 12.5 The diffraction intensity is stronger, indicating that the doping of Ni element can effectively improve the crystallinity of the material. Especially the improvement of Fe-Si phase crystallinity, the reaction of Si and metal is enhanced. After dealloying, NS-Fe 73 Ni2Si 12.5 B 12.5 , Fe-Si phase disappears, Fe phase appears, indicating that Si is dissolved in the alkaline solution during the dealloying process. Compared with the uncorroded phase, the intensity of the diffraction peak at 42.611° is weakened, indicating that part of the B element is dissolved in the process of dealloying corrosion. In the process of corrosion, active components Si and B and part of Fe atoms dissolve on the electrolyte interface, form vacancies, cause Ni to migrate and recombine on the surface, and make the electronic density redistribute, form a strong electronic structure between Ni and Fe, optimize the adsorption and desorption of intermediates in the reaction process, and thus improve the hydrogen evolution reaction activity.

[0099] From the a graph and the b graph in Figure 8 , after corrosion, NS-Fe 73 Ni2Si 12.5 B 12.5 The surface forms a nanosheet layered structure, but part of the area is not completely corroded. From the c graph in Figure 8 , compared with NS-Fe 75 Si 12.5 B 12.5 without doping Ni, the surface of the nanometer porous structure is smaller and more. From the d graph and the e graph in Figure 8 , the number and size of the sheet layer in the hole are seen.

[0100] From the f graph in Figure 8 , NS-Fe 73 Ni2Si 12.5 B 12.5 contains the content distribution of four elements of Fe, Ni, Si and B, which is consistent with the result of X-ray diffraction spectrum.

[0101] From the a graph in Figure 9 , the existence of Fe, Ni, Si, B, C and O elements and no other element characteristics confirms that the purity of the preparation of the nanometer catalyst is at a high level. As shown in b in Figure 9 , the binding energy peak signal is found, indicating that the Ni element is successfully doped into NS-Fe75 Si 12.5 B 12.5 In the middle. Observation Figure 9 Figure c shows that, compared to NS-Fe 75 Si 12.5 B 12.5 NS-Fe 73 Ni2Si 12.5 B 12.5 A small amount of Fe remains on the surface after dealloying. 0 The characteristic peak (706.13 eV) indicates that Ni doping alters the valence state of Fe, making Fe atoms less susceptible to oxidation during dealloying. (Observation) Figure 9 The d-plot shows that, compared to NS-Fe 75 Si 12.5 B 12.5 and NS-Fe 73 Ni2Si 12.5 B 12.5 X-ray photoelectron spectroscopy of Si 2p, NS-Fe 73 Ni2Si 12.5 B 12.5 The enhanced peak intensity of the Si-metal bond on the surface indicates that Ni doping facilitates the bonding between Si and the metal. Figure 9 The e-plot shows that after Ni doping, the strength of Si-O bonds and Fe-O bonds weakens, while the strength of Fe-OH bonds gradually increases, which is beneficial to the bonding between Fe and OH. The generated FeOOH enhances the catalytic activity of the nanocatalyst.

[0102] Depend on Figure 10 From Figure a, we can see that Fe 73 Ni2Si 12.5 B 12.5 The performance is the best, at a current density of 10 mA / cm². 2 The hydrogen evolution overpotential decreased to 168 mV, indicating that Ni doping enhances the interaction between electrons; however, higher Ni content actually hinders the adsorption and dissociation of hydrogen ions. (Observation) Figure 10 From graph b, we can see that Fe 73 Ni2Si 12.5 B 12.5 with Fe 75 Si 12.5 B 12.5 The increase of 35.4 mV is due to the fact that the introduction of cation Ni doping induces a redistribution of electron density, precisely modulates the electronic structure of Fe-Ni, optimizes the adsorption and dissociation of intermediates in the reaction, and thus improves the catalytic activity of the nanocatalyst for the hydrogen evolution reaction. NS-Fe 73 Ni2Si 12.5 B 12.5with Fe 73 Ni2Si 12.5 B 12.5 In comparison, the performance was improved by 55 mV through dealloying corrosion. This is because dealloying corrosion causes the nanocatalyst surface to form a nanoporous structure, which can expose more active sites, increase the electrochemical surface area, and exhibit better hydrogen evolution reaction performance.

[0103] From graph c in 9, we can see that NS-Fe 75 Si 12.5 B 12.5 overpotential and NS-Fe 65 Ni 10 Si 12.5 B 12.5 They are quite similar. (By) Figure 10 From the d-plot, we can see that NS-Fe 73 Ni2Si 12.5 B 12.5 The Tafel slope is only 158 mV / dec, much smaller than that of NS-Fe. 70 Ni5Si 12.5 B 12.5 (182) NS-Fe 67 Ni8Si 12.5 B 12.5 (198), NS-Fe 65 Ni 10 Si 12.5 B 12.5 (205)Fe 73 Ni2Si 12.5 B 12.5 (175) A lower slope indicates that the smaller the Tafel slope, the faster the electron transfer and catalytic reaction kinetics, and the better the NS-Fe 73 Ni2Si 12.5 B 12.5 It can reduce hydrogen ion concentration at relatively low overpotential values. Observation Figure 10 From the e-graph, we can see that NS-Fe 73 Ni2Si 12.5 B 12.5 NS-Fe 70 Ni5Si 12.5 B 12.5 NS-Fe 67 Ni8Si 12.5 B 12.5 NS-Fe 65 Ni 10 Si 12.5 B 12.5 Fe 73 Ni2Si 12.5 B 12.5 and NS-Fe75 Si 12.5 B 12.5 The charge transfer resistance is about 2.515 Ω, 2.537 Ω, 3.172 Ω, 3.406 Ω, 2.578 Ω and 3.67 Ω, respectively, NS-Fe 73 Ni2Si 12.5 B 12.5 The smaller charge transfer resistance (2.515 Ω) indicates that Ni and Fe have a strong synergistic effect on improving electrical conductivity, which is conducive to fast electron transfer and improves the hydrogen evolution reaction performance.

[0104] The f figure in Figure 10 is C dl The figure, NS-Fe 73 Ni2Si 12.5 B 12.5 The C dl The value is 0.279 mF / cm, which is significantly greater than NS-Fe 70 Ni5Si 12.5 B 12.5 (0.140 mF / cm), NS-Fe 67 Ni8Si 12.5 B 12.5 (0.106 mF / cm), NS-Fe 65 Ni 10 Si 12.5 B 12.5 (0.077 mF / cm) and Fe 73 Ni2Si 12.5 B 12.5 (0.136 mF / cm), indicating that under the action of doping and etching process, NS-Fe 73 Ni2Si 12.5 B 12.5 has rich surface catalytic active sites, according to the formula ECSA= C dl / C s , NS-Fe 73 Ni2Si 12.5 B 12.5的 The ECSA value is calculated as 6.975 cm 2 , which is attributed to the interface charge redistribution and the synergistic effect between Ni-Fe, which can enhance the contact area with the electrolyte, thereby improving the charge transfer capacity at the interface and promoting the mass transfer between the reactants and products.

[0105] At the same time, the chronopotentiometry method was used to evaluate NS-Fe 73 Ni2Si 12.5 B12.5 Long-term stability in 1 mol / L KOH solution. As shown in a graph in FIG. Figure 11 As shown in a graph in FIG. 2b, after 1000 cycles, the NS-Fe 73 Ni2Si 12.5 B 12.5 The linear sweep voltammetry curve did not change significantly before and after the cycle, indicating that the hydrogen evolution reaction was stable. As shown in a graph in FIG. Figure 11 As shown in a graph in FIG. 2b, after 20 h of hydrogen evolution reaction, the hydrogen evolution reaction current density decreased to 86% of the initial value, indicating that the hydrogen evolution reaction could be performed stably for a long time.

[0106] Co-doped NS-Fe 75 Si 12.5 B 12.5 , so that the nano-catalyst particles are finer and the specific surface area is larger. The doping of Co can cause an electronic effect, change the electronic state of NS-Fe 75 Si 12.5 B 12.5 , and thus affect the catalytic performance. In addition, the synergistic effect between Co and Fe, Si and B can also lead to the formation of new active sites, increasing the electrochemical active area. 75 Si 12.5 B 12.5 , which is beneficial to improve the hydrogen evolution reaction performance. This is due to the interface charge redistribution and the synergistic effect between Ni-Fe, which can enhance the contact area with the electrolyte, thereby improving the charge transfer ability at the interface and promoting the mass transfer between the reactants and products.

[0107] It should be noted that when the present application involves a numerical range, it should be understood that both endpoints of each numerical range and any number between the two endpoints can be selected. Since the same steps and examples are used, the preferred embodiments of the present application are described to prevent redundancy.

[0108] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they understand the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the present application.

Claims

1. A nanocatalyst, characterized in that, The nano-catalyst is a transition metal doped Fe-Si-B based alloy, and its chemical general formula is Fe 75-x M x Si 12.5 B 12.5 , and x is 2-10; M is selected from transition metals Co or Ni.

2. The nanocatalyst of claim 1, wherein, The surface of the nanocatalyst is in a lamellar structure.

3. The nanocatalyst of claim 1, wherein, When M is the transition metal Co, the nanocatalyst is Fe 73 Co2Si 12.5 B 12.5 , Fe 70 Co5Si 12.5 B 12.5 , Fe 67 Co8Si 12.5 B 12.5 or Fe 65 Co 10 Si 12.5 B 12.5 .

4. The nanocatalyst of claim 1, wherein, When M is the transition metal Ni, the nanocatalyst is Fe 73 Ni2Si 12.5 B 12.5 , Fe 70 Ni5Si 12.5 B 12.5 , Fe 67 Ni8Si 12.5 B 12.5 or Fe 65 Ni 10 Si 12.5 B 12.5 .

5. A method of preparing the nanocatalyst of claim 1, characterized by, The method comprises the following steps: According to the chemical formula Fe 75-x M x Si 12.5 B 12.5 , M is transition metal Co or Ni, weighing FeB, FeSi and Fe, and Co or Ni, and mixing to obtain a mixture; wherein, x is 2~10; The mixed material is subjected to a smelting treatment to obtain a transition metal doped Fe-Si-B based alloy; The transition metal doped Fe-Si-B based alloy is subjected to a dealloying corrosion treatment to corrode off Si atoms and part of B atoms on the surface of the transition metal doped Fe-Si-B based alloy, so that the surface presents a lamellar structure, and a nanocatalyst is obtained.

6. The method for preparing the nanocatalyst according to claim 5, characterized in that, The dealloying corrosion treatment is performed in a strong alkali solution with a concentration of 0.5-4 mol / L for 2-3 hours.

7. The method for preparing the nanocatalyst according to claim 6, characterized in that, The strong alkali solution is selected from KOH solution or NaOH solution.

8. The method for preparing the nanocatalyst according to claim 5, characterized in that, The smelting treatment is performed at 1800-2200 DEG C for 5-10 minutes.

9. Use of the nanocatalyst of claim 1 in the preparation of an electrolytic water hydrogen evolution reaction catalyst.

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