Pt monatomic loaded amorphous / crystalline NiFe LDH electro-catalytic material, preparation method and application

Abstract

The invention belongs to the technical field of electro-catalytic materials, and particularly relates to a Pt monatomic loaded amorphous / crystalline NiFe LDH electro-catalytic material, a preparation method and application. According to the preparation method, conductive foamed nickel is mainly used as a self-supporting carrier, an ac-NiFe LDH precursor is prepared through constant-voltage electrodeposition, and then Pt-SAs is loaded on the ac-NiFe LDH through cyclic voltammetry electrodeposition to obtain the Pt-SAs / ac-NiFe LDH electrocatalytic material. The preparation process disclosed by the invention is simple, can efficiently utilize noble metal materials and reduce the cost, is suitable for industrial preparation of the electrocatalyst, and solves the problem that other synthesis technologies at present are complicated and high in cost and cannot meet the industrial production of hydrogen production by electrolysis of alkaline fresh water and sea water. The electrocatalyst synthesized by the invention has the full water electrolysis performance far better than that of HER and RuO2 (+) Pt / C (-) of commercial Pt / C under the industrial current density, and has the application potential of industrial electrochemical water decomposition.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and in particular relates to a Pt single atom-loaded amorphous / crystalline NiFeLDH electrocatalytic material, a preparation method and an application thereof. Background Art

[0002] Hydrogen production technology by water electrolysis is one of the main ways to obtain high-purity green hydrogen. At present, precious metal-based electrocatalysts are still the most advanced electrocatalyst materials for hydrogen evolution reaction (HER). However, the high price of precious metals limits their large-scale industrial application. Loading precious metals in the form of single atoms into non-precious metal materials is an effective way to reduce the cost of synthetic catalysts and improve catalyst performance. Amorphous materials are an effective strategy to improve the performance of electrocatalysts in phase engineering. Due to the presence of a large number of unsaturated dangling bonds and long-range disordered atomic arrangements, they can be used to capture and stabilize precious metal single atoms. Based on this, Professor Guo Lin and others from Beijing University of Aeronautics and Astronautics reported a Pt single atom-loaded amorphous Ni(OH) 2 HER electrocatalyst. Due to Ni(OH) 2 The amorphous structure of Pt-SA / a-Ni(OH) disperses and anchors a large number of Pt atoms on its surface. 2 The electrocatalyst only needs 64 mV overpotential to reach 10 mA cm in 1 M KOH solution. -2 The current density can be 10 mA cm -2 Professor Mu Shichun of Wuhan University of Technology and others reported a Ru single-atom doped amorphous MoO 3-x electrocatalyst, and through amorphous MoO 3-x Unsaturated sites in amorphous materials stabilize Ru single atoms, Ru SAs-MoO 3-x The electrocatalysts can reach 10 and 100 mA cm-2 with overpotentials of 36 and 86 mV, respectively, in 1 M KOH solution. -2 The current density is 50 mA cm -2 In addition, Ru SAs-MoO 3-x When the electrocatalyst is used as both the cathode and anode electrodes of the full water splitting electrolyzer, only a cell voltage of 1.716 and 1.759 V is required to achieve 100 mA cm in 1 M KOH solution and 1 M KOH seawater solution. -2 Although the literature reported so far has shown good performance in anchoring noble metal atoms on amorphous materials and in alkaline freshwater and seawater electrolysis, the poor conductivity of amorphous materials and the insufficient performance and stability of water electrolysis for hydrogen production at high current density still have a large gap with industrial applications.

[0003] As a clean and efficient energy carrier, hydrogen energy has become an important direction for the transformation of the global energy system. Hydrogen production by water electrolysis is considered to be an important technology for achieving large-scale green hydrogen production because it can be driven by renewable energy. At present, industrialized hydrogen production by water electrolysis is still mainly based on alkaline freshwater electrolysis. However, the global freshwater resources are limited, making seawater electrolysis more valuable in coastal arid areas. However, due to the complex impurity ions (such as Cl - Mg 2+ , Ca 2+ The problems of high current density, such as corrosion of catalyst materials and membrane contamination, can easily cause electrolysis efficiency and catalyst stability. Therefore, it is necessary to develop electrocatalysts that are both efficient and corrosion-resistant to meet the requirements of stable electrolysis of fresh water / seawater at industrial current density.

[0004] Amorphous / crystalline NiFe LDH shows potential application value in alkaline hydrogen evolution reaction (HER) due to its abundant defect sites, tunable electronic structure and good conductivity. However, its catalytic performance is still limited in many aspects. On the one hand, NiFe LDH has limited active sites, Ni 2+ Although it can effectively adsorb water molecules (H 2 O), but Fe 3+ Hydrogen adsorption intermediate (H ad ) has weak binding ability, resulting in limited Volmer step kinetics. On the other hand, under high current density, NiFeLDH is prone to lattice collapse, affecting catalytic activity and long-term stability. In addition, although precious metal catalysts have excellent HER activity, their high cost and resource scarcity severely limit their industrial application. Therefore, how to uniformly and stably load low-load precious metal single atoms on amorphous / crystalline NiFeLDH structures and maintain good structural stability under high current density conditions is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention discloses a Pt single atom loaded amorphous / crystalline NiFe LDH electrocatalytic material, a preparation method and an application thereof.

[0006] It should be noted that the present invention uses a self-supporting Pt-SAs / ac-NiFe LDH electrode to overcome the problems of active site blockage and charge transfer difficulties caused by the use of polymer binders. In addition, the Pt-SAs / ac-NiFe LDH electrocatalyst exhibits excellent hydrogen evolution reaction (HER) catalytic performance in alkaline freshwater and seawater electrolyzers at industrial current density. For alkaline freshwater and seawater HER, the Pt-SAs / ac-NiFe LDH electrocatalyst requires an overpotential of 141 and 138 mV, respectively, to achieve 1000 mA cm -2 This is much better than commercial Pt / C (which requires 376 mV and 400 mV to achieve 1000 mA cm for alkaline freshwater and seawater HER, respectively). -2 The self-supporting Pt-SAs / ac-NiFe LDH and ac-NiFe LDH electrocatalysts were used as cathode and anode electrodes, respectively, to assemble a full water electrolysis cell (ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-)), which can achieve 1000mAcm in alkaline fresh water with a driving voltage of only 1.74V. -2 The current density is also better than RuO 2 (+)||Pt / C(-) electrolyzer (2.24 V). In summary, the Pt-SAs / ac-NiFe LDH electrocatalyst has the potential for application in industrial electrochemical water splitting.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The first technical purpose of the present invention is to provide a Pt single atom loaded amorphous / crystalline NiFe LDH electrocatalytic material, wherein the material is a Pt-SAs / ac-NiFe LDH nanosheet, which mainly uses conductive nickel foam as a self-supporting carrier, prepares an ac-NiFe LDH precursor by constant voltage electrodeposition, and then loads Pt-SAs onto ac-NiFe LDH by cyclic voltammetry electrodeposition to obtain the Pt-SAs / ac-NiFe LDH electrocatalytic material.

[0009] The second technical purpose of the present invention is to provide a method for preparing the Pt single atom-loaded amorphous / crystalline NiFeLDH electrocatalytic material as described above, comprising the following steps:

[0010] Step (1): Pre-treat the nickel foam by first forming a 2×2 cm 2 The nickel foam was immersed in 3 mol / L hydrochloric acid for 15 min, then in deionized water for 6 min, and finally in ethanol for 5 min, and then naturally air-dried for later use;

[0011] Step (2): 0.65 mmol Ni(NO 3 ) 2 6H 2 O (analytical grade, ≥98%), 0.9mmol Fe(NO 3 ) 3 9H 2 O (trace analytical grade, ≥99.99%) was dissolved in 60 mL of deionized water and stirred well;

[0012] Step (3): On a CHI 760E electrochemical workstation, the pretreated NF (2×2 cm 2 ) was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the carbon rod was used as the counter electrode for electrodeposition. The deposition voltage was -1 V (vs. Hg / HgO) and the deposition time was 6 min.

[0013] Step (4): Rinse the nickel foam after the above reaction with deionized water for several times, and then dry it in air to obtain the ac-NiFe LDH precursor;

[0014] Step (5): Add 50 μmol K 2 PtCl 4 (analytical grade, ≥98%) was dissolved in 60 mL of deionized water and stirred well;

[0015] Step (6): On a CHI 760E electrochemical workstation, ac-NiFe LDH precursor (2×2 cm 2 ) was used as the working electrode, the SCE electrode was used as the reference electrode, and the platinum sheet was used as the counter electrode for electrodeposition. The deposition voltage ranged from 0 to -1.8 V (vs. SCE), and the number of deposition cycles was 60 cycles.

[0016] Step (7): The material after the above reaction is rinsed with deionized water for several times, and then dried in air to obtain the Pt-SAs / ac-NiFe LDH electrocatalyst.

[0017] The third technical purpose of the present invention is to provide an application of the Pt single atom-loaded amorphous / crystalline NiFeLDH electrocatalytic material as described above in the electrolysis of fresh water and seawater to produce hydrogen at industrial current density.

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

[0019] 1) The present invention obtains a Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalyst with high loading (2.55wt%) and good dispersibility through a two-step simple electrodeposition method. The preparation process disclosed in the present invention is simple, can efficiently utilize precious metal materials and reduce costs, is suitable for industrial preparation of electrocatalysts, and solves the problem that other current synthesis technologies are complex and costly and cannot meet the industrial production problem of electrolysis of alkaline fresh water and seawater to produce hydrogen.

[0020] 2) The electrocatalyst synthesized in this invention has much better HER and RuO performance than commercial Pt / C at industrial current density. 2 Full water electrolysis performance of (+)||Pt / C(-). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the synthesis of the Pt-SAs / ac-NiFe LDH catalyst described in the present invention.

[0023] Figure 2 The crystal structure and microstructure characterization of the ac-NiFe LDH catalyst of the present invention. (a) XRD diffraction pattern; (b) TEM image of ac-NiFe LDH; (c) HRTEM image of ac-NiFe LDH; (dg) element mapping images of ac-NiFe LDH.

[0024] Figure 3 The microstructure characterization of the Pt-SAs / ac-NiFe LDH catalyst of the present invention. (a) SEM image of Pt-SAs / ac-NiFe LDH; (b) TEM image of Pt-SAs / ac-NiFe LDH; (c) STEM image of Pt-SAs / ac-NiFe LDH; (d) HRTEM image of Pt-SAs / ac-NiFe LDH; (e, f) FFT images of region I and region II in Figure (d); (gi) AC-HAADF-STEM image of Pt-SAs / ac-NiFe LDH; (jn) element mapping image of Pt-SAs / ac-NiFe LDH.

[0025] Figure 4The HER performance of the samples obtained at different electrodeposition times in alkaline fresh water according to the present invention. (a) LSV diagram of the samples obtained at different electrodeposition times; (b) overpotential at different current densities.

[0026] Figure 5 The HER performance of the samples obtained at different electrodeposition cycles in alkaline fresh water according to the present invention is shown in Figure 1. (a) LSV diagram of the samples obtained at different electrodeposition times; (b) overpotential at different current densities.

[0027] Figure 6 The HER performance of the prepared catalysts described in the present invention in alkaline fresh water. (a) LSV diagram of different synthesized catalysts; (b) overpotential of the synthesized catalysts at different current densities; (c) overpotential of Pt-SAs / ac-NiFe LDH and Pt / C catalysts at 500 mA cm -2 Stability test under current density.

[0028] Figure 7 The HER performance of the prepared catalysts described in the present invention in alkaline seawater. (a) LSV diagram of different synthesized catalysts; (b) overpotential of the synthesized catalysts at different current densities; (c) overpotential of Pt-SAs / ac-NiFe LDH and Pt / C catalysts at 500 mA cm -2 Stability test under current density.

[0029] Figure 8 The performance of the catalyst prepared in the present invention in the full electrolysis of alkaline fresh water. (a) ac-NiFeLDH(+)||Pt-SAs / ac-NiFe LDH(-) and RuO 2 LSV diagram of (+)||Pt / C(-); (b) ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-) and RuO 2 Overpotential of (+)||Pt / C(-) at different current densities; (c) ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-) and RuO 2 (+)||Pt / C(-) at 500 mA cm -2 Stability test under current density. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0032] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0033] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0034] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0035] The invention discloses a preparation method of a Pt single atom-loaded amorphous / crystalline NiFe LDH and application of the LDH in producing hydrogen by electrolyzing fresh water and seawater at an industrial current density.

[0036] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0037] Example 1

[0038] A schematic diagram of the synthesis of a Pt-SAs / ac-NiFe LDH catalyst is shown in Figure 1 As shown, the specific steps include:

[0039] Step (1): Pre-treat the nickel foam by first forming a 2×2 cm 2 The nickel foam was immersed in 3 mol / L hydrochloric acid for 15 min, then in deionized water for 6 min, and finally in ethanol for 5 min, and then naturally air-dried for later use;

[0040] Step (2): 0.65 mmol Ni(NO 3 ) 2 6H2 O (analytical grade, ≥98%), 0.9mmol Fe(NO 3 ) 3 9H 2 O (trace analytical grade, ≥99.99%) was dissolved in 60 mL of deionized water and stirred well;

[0041] Step (3): On a CHI 760E electrochemical workstation, in a three-electrode system, a constant voltage electrodeposition method was used in the mixed solution of step (2) at a preparation temperature of 25°C to deposit the pretreated NF (2×2 cm 2 ) was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the carbon rod was used as the counter electrode for electrodeposition. The deposition voltage was -1 V (vs. Hg / HgO) and the deposition time was 6 min.

[0042] Step (4): Rinse the nickel foam after the above reaction with deionized water for several times, and then dry it in air to obtain the ac-NiFe LDH precursor;

[0043] Step (5): Add 50 μmol K 2 PtCl 4 (analytical grade, ≥98%) was dissolved in 60 mL of deionized water and stirred well;

[0044] Step (6): On a CHI 760E electrochemical workstation, ac-NiFe LDH precursor (2×2 cm 2 ) was used as the working electrode, the SCE electrode was used as the reference electrode, and the platinum sheet was used as the counter electrode for electrodeposition. The deposition voltage ranged from 0 to -1.8 V (vs. SCE), and the number of deposition cycles was 60 cycles.

[0045] Step (7): The material after the above reaction is rinsed with deionized water for several times, and then dried in air to obtain the Pt-SAs / ac-NiFe LDH electrocatalyst.

[0046] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following comparative examples and application examples are used to further illustrate the technical features disclosed in the present invention, but they should not be understood as limitations of the present invention. Other improvements made by those skilled in the art based on the above invention content without creative work are also considered to fall within the scope of protection of the present invention.

[0047] Comparative Example 1: HER catalytic performance of samples prepared with different electrodeposition times in alkaline fresh water by three-electrode system testing

[0048] A series of pre-treated NF (2×2 cm 2 ) is the working electrode (1×1cm 2 ), carbon rod as counter electrode and Hg / HgO as reference electrode were used to test the HER performance at high current density in 1 M KOH solution.

[0049] like Figure 4 As shown in the figure, the HER activity of the ac-NiFe LDH catalyst prepared with an electrodeposition time of 6 min is better than that of ac-NiFe LDH-4 and ac-NiFe LDH-8, indicating that the ac-NiFe LDH catalyst prepared with an electrodeposition time of 6 min is the optimal precursor.

[0050] Comparative Example 2: HER catalytic performance of samples prepared with different electrodeposition cycles in alkaline fresh water by three-electrode system testing

[0051] A series of ac-NiFe LDH precursors (2×2 cm 2 ) is the working electrode (1×1cm 2 ), platinum sheet as counter electrode and SCE electrode as reference electrode were used to test the HER performance at high current density in 1 M KOH solution.

[0052] like Figure 5 As shown in the figure, the HER activity of the Pt-SAs / ac-NiFe LDH catalyst prepared with 60 cycles of electrodeposition is better than that of the samples obtained with 40 and 80 cycles of electrodeposition, indicating that the Pt-SAs / ac-NiFe LDH catalyst prepared with 60 cycles of electrodeposition is the optimal electrocatalyst.

[0053] It should be noted that the samples used in the following application examples are all prepared in the above-mentioned Example 1.

[0054] Application Example 1: Testing the HER catalytic performance of the prepared catalyst in alkaline fresh water using a three-electrode system

[0055] The prepared sample was used as the working electrode (1×1 cm 2 ), carbon rod as counter electrode and Hg / HgO as reference electrode, and the HER performance of Pt-SAs / ac-NiFe LDH catalyst at high current density was tested in 1M KOH solution.

[0056] like Figure 6 a and Figure 6 As shown in (b), the prepared Pt-SAs / ac-NiFe LDH catalyst exhibits excellent HER performance, which requires an overpotential of 54, 97, and 141 mV to reach 100, 500, and 1000 mA cm-2 This is not only better than the performance of other comparative samples, but also much better than the benchmark Pt / C catalyst (η 100 =118mV, η 500 =273mV, η 1000 =376mV).

[0057] In addition, from Figure 6 c It can be seen that the Pt-SAs / ac-NiFe LDH catalyst has a -2 The stability at a current density of more than 100 h is much better than that of Pt / C catalyst. The above shows that the introduction of Pt single atoms significantly improves the HER performance of Pt-SAs / ac-NiFe LDH under high current conditions, and also shows that Pt-SAs / ac-NiFe LDH catalyst has the potential for industrial application in alkaline electrolysis of fresh water to produce hydrogen.

[0058] Application Example 2: Testing the HER catalytic performance of the prepared catalyst in alkaline seawater using a three-electrode system

[0059] The prepared sample was used as the working electrode (1×1 cm 2 ), carbon rod as counter electrode and Hg / HgO as reference electrode, and the HER performance of Pt-SAs / ac-NiFe LDH catalyst at high current density was tested in 1MKOH natural seawater solution.

[0060] like Figure 7 a and Figure 7 As shown in (b), the prepared Pt-SAs / ac-NiFe LDH catalyst exhibits excellent HER performance, which requires an overpotential of 56, 105, and 138 mV to reach 100, 500, and 1000 mA cm -2 This is not only better than the performance of other comparative samples, but also much better than the benchmark Pt / C catalyst (η 100 =102mV,

[0061] η 500 =275mV, η 1000 =400mV).

[0062] In addition, from Figure 7 c It can be seen that the Pt-SAs / ac-NiFe LDH catalyst has a -2 The stability at a current density of more than 100 h is much better than that of Pt / C catalyst. All these indicate that Pt-SAs / ac-NiFe LDH catalyst has the potential for industrial application in alkaline electrolysis of seawater to produce hydrogen.

[0063] Application Example 3: Full Electrolysis Water Performance Test

[0064] The Pt-SAs / ac-NiFe LDH electrocatalyst was used as the cathode and ac-NiFe LDH as the anode to form a double-electrode system for full water electrolysis in 1M KOH solution, named ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-). 2 and Pt / C as anode and cathode electrodes, respectively, to form a two-electrode system for comparison testing and named RuO 2 (+)||Pt / C(-).

[0065] like Figure 8 a and Figure 8 As shown in b, the catalytic performance of ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-) for water electrolysis is much better than that of the benchmark RuO 2 Specifically, ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-) require voltages of 1.51, 1.64, and 1.74 V to achieve 100, 500, and 1000 mA cm -2 The current density of RuO 2 To achieve the same current density, (+)||Pt / C(-) requires voltages of 1.67, 1.98, and 2.24 V, respectively.

[0066] In addition, if Figure 8 As shown in Fig. c, ac-NiFe LDH(+)||Pt-SAs / ac-NiFe LDH(-) has no obvious voltage increase after at least 100h of stability test, which is much better than RuO2(+)||Pt / C(-). The present invention provides a new idea for the preparation and modification of high-efficiency electrocatalysts.

[0067] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalytic material, characterized in that: The material is a Pt-SAs / ac-NiFe LDH nanosheet, which mainly uses conductive nickel foam as a self-supporting carrier, prepares an ac-NiFeLDH precursor by constant voltage electrodeposition, and then loads Pt-SAs on the ac-NiFe LDH by cyclic voltammetry electrodeposition to obtain a Pt-SAs / ac-NiFeLDH electrocatalytic material.

2. A method for preparing the Pt single atom supported amorphous / crystalline NiFe LDH electrocatalytic material as claimed in claim 1, characterized in that: The method is specifically operated as follows: Step 1: Preparation of ac-NiFe LDH precursor: Nickel nitrate hexahydrate and iron nitrate nonahydrate are dissolved in deionized water to form a homogeneous solution, and then electro-deposited in the homogeneous solution by constant voltage electrodeposition in a three-electrode system, with the pretreated NF as a working electrode, the Hg / HgO electrode as a reference electrode, and the carbon rod as a counter electrode to obtain an ac-NiFe LDH precursor; Step 2: Preparation of Pt-SAs / ac-NiFe LDH electrocatalyst: In a three-electrode system, cyclic voltammetric electrodeposition is performed in a K2PtCl4 solution, with the ac-NiFeLDH precursor obtained in step 1 as the working electrode, the SCE electrode as the reference electrode, and the platinum sheet as the counter electrode. After the electrodeposition is completed, the sample is rinsed several times with deionized water and dried to obtain the Pt-SAs / ac-NiFe LDH electrocatalytic material.

3. The method for preparing the Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalytic material according to claim 2, characterized in that: In the homogeneous solution, the molar ratio of nickel nitrate hexahydrate, iron nitrate nonahydrate and deionized water is 0.65 mmol:0.9 mmol:60 mL.

4. The method for preparing the Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalytic material according to claim 2, characterized in that: In the homogeneous solution, the amount ratio of potassium chloroplatinite to deionized water is 50 μmol:60 mL. The process parameters of the constant voltage electrodeposition method for preparing the ac-NiFe LDH electrocatalyst are as follows: The preparation temperature was 25°C, the pretreated nickel foam was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, the carbon rod was used as the counter electrode, the deposition voltage was -1 V (vs. Hg / HgO), and the deposition time was 6 min.

5. The method for preparing the Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalytic material according to claim 2, characterized in that: The process parameters of the cyclic voltammetric electrodeposition method are as follows: The preparation temperature was 25°C, the ac-NiFe LDH precursor was the working electrode, the SCE electrode was the reference electrode, the platinum sheet was the counter electrode, the deposition voltage ranged from 0 to -1.8 V (vs. SCE), and the number of deposition cycles was 60.

6. An application of the Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalyst material as claimed in claim 1 or the Pt single atom-loaded amorphous / crystalline NiFe LDH electrocatalyst material prepared by the method as claimed in claim 2 in electrolyzing fresh water and seawater to produce hydrogen at industrial current density.

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