CN115522223A - Fluorine-doped non-noble metal electrocatalyst and preparation method and application thereof - Google Patents

Abstract

The invention discloses a fluorine-doped non-noble metal electrocatalyst, a preparation method and application thereof. The electrocatalyst comprises an active amorphous layer and a substrate, the active amorphous layer is distributed on the surface of the substrate, and the active amorphous layer is a fluorine-doped non-noble metal oxyhydroxide. In the present invention, the surface of the matrix is converted into oxyhydroxide by an electrochemical anodic oxidation method, and at the same time, the fluoride ion is doped to improve the electrocatalytic activity of oxygen evolution. The method has easy-to-obtain raw materials, simple operation and convenient mass production. The prepared catalyst has both high intrinsic performance and abundant active sites, and can efficiently and stably catalyze the oxygen evolution reaction in water electrolysis under alkaline conditions. Catalyst Catalyst.

Description

A kind of fluorine-doped non-noble metal electrocatalyst and its preparation method and application

technical field

The invention belongs to the field of hydrogen production technology and material technology, and specifically relates to a fluorine-doped non-noble metal electrocatalyst and its preparation method and application.

Background technique

The world's growing demand for energy and the consumption of fossil fuels are major challenges to achieving sustainable development. Hydrogen is generally considered to be a clean and efficient secondary energy carrier, and its large-scale industrial application is expected to fundamentally solve global problems such as energy shortage and environmental pollution. Therefore, the development of hydrogen energy utilization technology has become the focus of energy development strategies of countries around the world . To promote the industrial application of hydrogen energy, it is necessary to build a complete hydrogen energy industry chain including hydrogen production, hydrogen storage, hydrogen fuel cells and other links, of which hydrogen production is the source. Among the existing hydrogen production methods, the coupling of hydrogen production by electrolysis of water and primary renewable energy such as solar energy and wind energy can become an ideal large-scale hydrogen production technology, and it is the best way to lead to the "hydrogen economy". Electrolysis of water involves two half-reactions of hydrogen evolution at the cathode and oxygen evolution at the anode. Reducing the overpotential of the two reactions, that is, reducing the energy consumption of the electrolysis reaction is the core of the development of electrolysis water technology. Among them, the oxygen evolution (OER) process at the anode involves a four-electron transfer reaction and becomes the main rate-limiting step for hydrogen production from water electrolysis.

In recent years, the development of new non-precious metal catalysts to achieve excellent catalytic performance while reducing material costs has become the mainstream trend in the field of electrolysis of water. According to literature reports, 3d transition metal compounds, such as oxides/hydroxides, nitrides, phosphides, sulfides, borides and other types of materials have good basic electrocatalytic oxygen evolution activity, but in general, Non-noble transition metal oxygen evolution electrocatalysts can achieve the lowest overpotential for oxygen evolution reaction due to the four-electron reaction and only the active sites have suitable adsorption energies for oxygen intermediates (OH*, O*, and OOH*). (T. H. Lee, S. A. Lee, H. Patk, M. J. Choi, D. Lee, H. W. Jang, ACS Appl. Energy Mater. 2020, 3, 1634-1643.). The heteroatom doping can optimize the electronic structure of the active site of the oxygen evolution catalyst, thereby optimizing the binding energy between the active site and the oxygen intermediate, so it is considered as an important means to obtain high-performance catalysts.

Contents of the invention

In view of the shortcomings and deficiencies in the prior art, the primary purpose of the present invention is to provide a fluorine-doped non-noble metal electrocatalyst and its preparation method and application. Due to its high electron affinity and electronegativity, fluoride ions can affect the electronic structure and physicochemical properties of metal catalysts, thereby changing the intrinsic activity of the catalysts. Therefore, non-noble metal catalysts can be modified by fluoride ion doping and the OER activity of the catalysts can be improved. The catalyst prepared by the invention has high intrinsic activity, can efficiently catalyze the oxygen evolution reaction of electrolyzed water under alkaline conditions, and has a catalytic performance close to that of a noble metal _RuO2 catalyst.

The object of the invention is achieved through the following technical solutions:

A fluorine-doped non-noble metal electrocatalytic oxygen evolution catalyst, the electrocatalyst includes an active amorphous layer and a substrate, the active amorphous layer is distributed on the surface of the substrate, and the active amorphous layer is a fluorine-doped non-noble metal oxyhydroxide. The active amorphous layer is amorphous oxyhydroxide.

Preferably, the non-noble metal in the fluorine-doped non-noble metal oxyhydroxide is at least one of Fe, Co and Ni.

Preferably, the substrate is a non-noble metal oxide or metal hydroxide, and the non-noble metal is at least one of Fe, Co, Ni and Mo.

Preferably, the thickness of the active amorphous layer is 2-5 nanometers; the active amorphous layer is obtained by electrochemical anodic oxidation of the substrate in an alkaline solution containing fluorine ions.

Preferably, the matrix exists in the form of nanosheets;

Preferably, the electrocatalyst further includes a carrier on which the substrate is supported; the carrier is one of metal foam, metal mesh, ion exchange resin and molecular sieve.

Preferably, the matrix is Ni(OH) ₂ , Co(OH) ₂ or NiMoO ₄ .

The above-mentioned preparation method of a fluorine-doped non-noble metal electrocatalyst comprises the following steps:

(1) adding the carrier material to a solution containing a non-noble metal salt, hydrothermally reacting, and growing a nanostructured catalyst precursor on the surface of the carrier material,

(2) The catalyst precursor described in step (1), is electrochemically anodized in an alkaline solution containing fluorine ions to obtain a fluorine-doped non-noble metal electrocatalyst.

Preferably, the non-noble metal salt in step (1) includes at least one of a non-noble metal halide and an oxo acid salt, and the non-noble metal includes at least one of Fe, Ni, Co, Mo;

Further preferably, the halide is chloride; the oxo acid salt is nitrate, carbonate, acetate and sulfate;

Preferably, the carrier material in step (1) is selected from one of metal foam, metal mesh, ion exchange resin and molecular sieve.

Preferably, the concentration of the non-noble metal salt in step (1) is 0.01-0.1M (when there are multiple non-noble metal salts, it is the total concentration); the solvent of the solution is water; the temperature of the hydrothermal reaction is 120 -180°C; the hydrothermal reaction time is 6-12 hours.

Preferably, the solution in step (1) also contains a precipitating agent; the precipitating agent is CO(NH ₂ ) ₂ ; the concentration of the precipitating agent is 0.1-1M.

Preferably, the fluoride ion in step (2) is at least one of sodium fluoride and potassium fluoride; the electrochemical anodic oxidation time is 0.5-1.5 h, and the current density is 5-20 mA cm ^-2 , so The concentration of the fluoride ion is 0.25-0.75M; the concentration of the alkaline solution is 0.5M-1.5M.

The application of the above-mentioned fluorine-doped non-noble metal electrocatalyst in the electrocatalytic water desorption oxygen.

Design principle of the present invention is:

The principle of the present invention is: for an electrocatalyst, intrinsic activity, number of active sites, and electrical conductivity are three elements that affect its apparent catalytic activity. Among them, the improvement of intrinsic activity can be achieved by doping elements, but because many compounds doped with transition metal elements may undergo phase separation during the oxygen evolution reaction process, the optional range of metal elements is limited. In order to improve the activity of the catalyst and expand the exploration range of doping elements, the catalyst provided by the present invention is designed to improve the intrinsic activity of the catalyst through the doping of anionic fluorine element, and provides a simple and easy preparation method to realize it. First, a nanosheet precursor containing catalyst active components and a high specific surface area is grown on the surface of the carrier material by a hydrothermal method, laying the foundation for the composition and structure of the material for the synthesis of a high-performance catalyst; Chemical anodization converts the surface of nanosheets into oxyhydroxides with high catalytic activity, and fluoride ions are doped into the surface of the catalyst while forming oxyhydroxides to improve the intrinsic activity of the catalyst; in summary, the present invention provides Electrochemical oxygen evolution catalysts have both high intrinsic activity and abundant active sites.

Advantage of the present invention and beneficial effect are:

(1) The key difference between the present invention and the traditional method is that the catalyst is prepared by electrochemical anodic oxidation in a fluorine-containing solution, and the active phase oxyhydroxide can be formed on the surface of the catalyst while doping fluoride ions into the catalyst to improve the intrinsic properties of the catalyst. activity; in addition, the hydrothermally synthesized ultrathin nanosheets exposed a large number of active sites, resulting in high catalytic activity for the oxygen evolution reaction.

(2) The new method for preparing a fluoride ion-doped non-precious metal oxygen evolution electrocatalyst provided by the present invention has easy-to-obtain raw materials, simple process, convenient mass production, and no pollution in the whole process.

(3) The present invention provides a non-precious metal oxygen evolution electrocatalyst doped with fluoride ions, which can efficiently catalyze the oxygen evolution reaction in electrolyzed water under alkaline conditions, and its comprehensive catalytic performance is close to that of noble metal _RuO2 catalysts.

Description of drawings

Figure 1 shows the hydrothermal sample Ni(OH) ₂ /NF of Example 1, NiOOH/Ni(OH) ₂ /NF after electrochemical anodization and F-NiOOH/Ni(OH) after electrochemical anodization doped with fluorine ions ) ₂ /NF X-ray diffraction pattern.

Fig. 2 is the SEM morphology of sample F-NiOOH/Ni(OH) ₂ /NF in Example 1 (a) hydrothermal state Ni(OH) ₂ /NF and (b) electrochemical anodic oxidation doped with fluoride ions picture.

Figure 3 is the (a) selected area electron diffraction pattern (b) high-resolution electron micrograph of the hydrothermal state Ni(OH) ₂ /NF in Example 1, and the F-NiOOH/Ni( (c) Selected area electron diffraction pattern (d) High-resolution electron micrograph of OH) ₂ /NF.

Figure 4 is the X-ray photoelectron of Ni(OH) ₂ /NF, NiOOH/Ni(OH) ₂ /NF and sample F-NiOOH/Ni(OH) ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 1 Spectrum.

Fig. ₅ is the _XANES spectrogram (a) and the EXAFS analysis result ( b).

Figure 6 shows the oxygen evolution reaction polarization of NiOOH/Ni(OH) ₂ /NF and samples F-NiOOH/Ni(OH) ₂ /NF, RuO ₂ /NF, NF after electrochemical anodic oxidation doping with fluorine ions in Example 1 Curve comparison chart.

Fig. 7 is a graph showing the relationship between the current density and the potential sweep rate of the sample F-NiOOH/Ni(OH) ₂ /NF(a) after NiOOH/Ni(OH) ₂ /NF and electrochemical anodization doped with fluoride ions in Example 1 (b) Impedance spectroscopy test results at open circuit potential.

Fig. 8 is a diagram of the durability test results of the sample F-NiOOH/Ni(OH) ₂ /NF in 1M KOH electrolyte containing 0.01M KF after electrochemical anodic oxidation doping with fluorine ions in Example 1.

FIG. 9 is a scanning electron microscope topography of the sample F-CoOOH/Co(OH) ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 2. FIG.

Fig. 10 is an X-ray diffraction pattern of the sample F-CoOOH/Co(OH) ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 2.

Fig. 11 is a high-resolution electron micrograph of the sample F-CoOOH/Co(OH) ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 2.

Fig. 12 is an X-ray photoelectron spectrum of the sample F-CoOOH/Co(OH) ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 2.

Fig. 13 is a graph comparing polarization curves of oxygen evolution reaction of samples F-CoOOH/Co(OH) ₂ /NF and RuO ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 2.

Figure 14 shows the oxygen evolution reaction polarization curves of samples F-CoOOH/Co(OH) ₂ /CF, CoOOH/Co(OH) ₂ /CF and RuO ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 3 Comparison chart.

Fig. 15 is a comparison diagram of the oxygen evolution reaction polarization curves of samples F-NiOOH/NiMoO ₄ /NF, NiOOH/NiMoO ₄ /NF and RuO ₂ /NF after electrochemical anodic oxidation doping with fluorine ions in Example 4.

Fig. 16 is a comparison diagram of polarization curves of oxygen evolution reaction of samples F-NiOOH/NiMoO ₄ /CF, NiOOH/NiMoO ₄ /CF and RuO ₂ /CF after electrochemical anodic oxidation doping with fluorine ions in Example 5.

Figure 17 shows the oxygen evolution reaction polarization curves of samples F-Ni _1-x Fe _x OOH/NiFeLDH/NF and Ni _1-x Fe _x OOH/NiFe LDH/NF after electrochemical anodic oxidation doping with fluorine ions in Example 6 Comparison chart.

detailed description

The present invention will be specifically described below in conjunction with the examples, but the embodiments and protection scope of the present invention are not limited to the following examples.

The present invention is described in detail below through specific examples.

Example 1

Synthesis, Structure and Catalytic Properties of F-NiOOH/Ni(OH) ₂ /NF Catalyst

Catalyst preparation:

(1) Nickel foam (NF) is used as the carrier, with a thickness of 1.80mm, a surface density of 650g/m ² , and a pore diameter of 0.20-0.80mm. Nickel foam (1×4cm ² ) was ultrasonically cleaned with ethanol for 10 minutes, activated with 1M hydrochloric acid solution for 5 minutes, and ultrasonically cleaned with deionized water for 10 minutes, and placed together with 30 mL of deionized aqueous solution containing NiSO ₄ ·6H ₂ O (0.02M). In a hydrothermal ax with a volume of 50mL, it was treated at a constant temperature of 140°C for 6 hours and then naturally cooled to room temperature. After the sample was fully cleaned, it was vacuum-dried at 60°C for 2 hours to obtain a hydrothermal sample Ni(OH) ₂ / NF.

(2) The 1×2cm ² hydrothermal sample is used as the working electrode, the counter electrode is a carbon plate, and the reference electrode is Hg/HgO, and electrochemical anodic oxidation doping is carried out in a mixed solution of 1M KOH and 0.5M KF. The current density was 15 mA cm ⁻² . The target catalyst F-NiOOH/Ni(OH) ₂ /NF was obtained after electrochemical anodization for 1h.

The difference between the preparation of NiOOH/Ni(OH) ₂ /NF and F-NiOOH/Ni(OH) ₂ /NF is that electrochemical anodic oxidation doping is carried out in 1M KOH solution; the others are the same.

Catalyst phase/structure/element chemical state characterization:

The X-ray diffraction and scanning electron microscope images of the hydrothermal sample obtained in this example and the sample after electrochemical anodization are shown in Fig. 1 and Fig. 2, respectively. According to the XRD analysis (Fig. 1), the synthesized hydrothermal sample and the electrochemical anodized sample are Ni(OH) ₂ crystalline phase. Scanning electron microscope observation (a, b in Figure 2) found that the hydrothermal sample had a nanosheet structure, and the morphology of the nanosheets did not change significantly after electrochemical anodic oxidation. Transmission electron microscope observation (c, d in Fig. 3) further confirms that the surface of the target catalyst is covered with an amorphous phase, and the substrate remains Ni(OH) ₂ .

According to the X-ray photoelectron spectroscopy analysis (Fig. 4), Ni ³⁺ signal appears in the sample after electrochemical anodization, while after fluorine element doping, the binding energy of Ni ³⁺ shifts to high binding energy. According to the EXAFS analysis results of b in Figure 5, it can be seen that the bond length of Ni-O(OH) is shortened after F doping, and F ^- replaces the position of O ² - or OH ^- in NiOOH, and according to a in Figure 5, it can be known that F After doping, the valence state increases, excluding the possibility of F- replacing O ^2- , so F replaces the position of ^OH- in NiOOH. This proves that F ions are doped into the nickel oxyhydroxide and replace the OH- position in the nickel oxyhydroxide. The above analysis confirms that the target catalyst is the F-NiOOH/Ni(OH ₎ catalyst supported by nickel foam.

Catalyst electrocatalytic performance test:

The oxygen evolution reaction polarization curve test results (Figure 6) show that the electrocatalytic activity of the oxygen evolution reaction of the catalyst after fluorine ^doping is improved by using this method. The overpotential is 30mV lower than that without fluorine doping, and the catalytic activity is better than that of the noble metal RuO ₂ catalyst; the oxygen evolution overpotential of 10mA cm ^-2 is respectively, NiOOH/Ni(OH) ₂ /NF: 300mV, F-NiOOH/Ni (OH) ₂ /NF: 268mV, RuO ₂ /NF: 272mV, NF: 340mV.

Fig. 7 shows the relationship between the current density and the potential sweep rate and the impedance spectrum test results of the target catalyst F-NiOOH/Ni(OH) ₂ /NF and the reference sample. The electrochemical specific surface area and load transfer resistance of the undoped sample and the target catalyst did not change significantly, that is, the number of active sites and conductivity of the catalyst did not change significantly. For electrocatalysts, three elements that affect their apparent catalytic activity are: intrinsic activity, number of active sites, and electrical conductivity. Therefore, the reason for the improvement of the catalyst activity is the improvement of the intrinsic activity of the catalyst after fluorine doping.

Figure 8 shows the stability test results of the F-NiOOH/Ni(OH) ₂ /NF catalyst. After 100 hours of constant flow measurement in the 1MKOH solution containing 0.01M KF, the catalyst activity did not decline significantly, indicating that the catalyst has excellent stability.

Example 2

Synthesis, Structure and Catalytic Properties of F-CoOOH/Co(OH) ₂ /NF Catalyst

Catalyst preparation:

The synthesis method of this example is similar to that of Example 1, except that the synthesis of the precursor is different.

The hydroxide precursor was synthesized by the following method: nickel foam (1×4cm ² ) was ultrasonically cleaned with ethanol for 10 minutes, activated with 1M hydrochloric acid solution for 5 minutes and ultrasonically cleaned with deionized water for 10 minutes, together with 30 mL of Co(NO ₃ ) ₂ ·6H ₂ O (3mmol), CO(NH ₂ ) ₂ (12mmol) deionized aqueous solution was placed in a hydrothermal ax with a volume of 50mL, treated at a constant temperature of 120°C for 8 hours, and then naturally cooled to room temperature. After sufficient cleaning, vacuum drying was carried out at 60° C. for 2 hours to obtain a hydroxide precursor Co(OH) ₂ /NF.

Catalyst phase/structure/element chemical state characterization:

Scanning electron microscope observation ( FIG. 9 ) revealed that the target catalyst was a 3D nano-curd structure composed of nano-sheets.

The XRD results show (Fig. 10) that the synthesized hydrothermal sample and the electrochemical anodized sample are Co(OH) ₂ crystalline phases.

TEM observation (Figure 11) further confirmed the existence of the surface amorphous phase in the target catalyst.

The XPS results showed (Fig. 12) that CoOOH was generated on the surface and F was doped into CoOOH.

Catalyst electrocatalytic performance test:

The oxygen evolution reaction polarization curve test results (Figure 13) show that the F-CoOOH/Co(OH) ₂ /NF catalyst has excellent electrocatalytic activity for the oxygen evolution reaction, which requires only 245mV in 1.0M potassium hydroxide alkali solution The oxygen evolution overpotential can reach the current density of 10mA cm ^-2 .

Example 3

Synthesis, Structure and Catalytic Properties of F-CoOOH/Co(OH) ₂ /CF Catalyst

Catalyst preparation:

In the synthesis method of this example, it is similar to Example 2, the only difference is that nickel foam (NF) is replaced by cobalt foam (CF).

Catalyst electrocatalytic performance test:

The oxygen evolution reaction polarization curve test results (Figure 14) show that the F-CoOOH/Co(OH) ₂ /CF catalyst has excellent electrocatalytic activity for the oxygen evolution reaction, which requires only 248mV in 1.0M potassium hydroxide lye Oxygen evolution overpotential can reach a current density of 10mAcm ^-2 .

Example 4

Synthesis, Structure and Catalytic Properties of F-NiOOH/NiMoO ₄ /NF Catalyst

Catalyst preparation:

In the synthesis method of this example, it is similar to that of Example 1, except that the hydroxide/oxide precursor is the only difference.

The oxide precursor was synthesized by the following method: nickel foam (1×4cm ² ) was ultrasonically cleaned with ethanol for 10 minutes, activated with 1M hydrochloric acid solution for 5 minutes and ultrasonically cleaned with deionized water for 10 minutes, together with 36 mL of Ni(NO ₃ ) ₂ · 6H ₂ O (4mmol), (NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O (1mmol), CO(NH ₂ ) ₂ (10mmol) deionized aqueous solution was placed in a water heating ax with a volume of 50mL, and the After being treated at a constant temperature of 150°C for 18 hours, it was naturally cooled to room temperature, and the prepared sample was fully cleaned and then vacuum-dried at 60°C for 2 hours to obtain the oxide precursor NiMoO ₄ /NF.

Catalyst electrocatalytic performance test:

The oxygen evolution reaction polarization curve test results (Figure 15) show that the F-NiOOH/NiMoO ₄ /NF catalyst has excellent electrocatalytic activity for the oxygen evolution reaction, and it only needs 252mV of oxygen evolution reaction in 1.0M potassium hydroxide alkali solution. Potential can reach the current density of 10mAcm ^-2 .

Example 5

Synthesis, Structure and Catalytic Properties of F-NiOOH/NiMoO ₄ /CF Catalyst

Catalyst preparation:

In the synthesis method of this example, similar to Example 4, only nickel foam (NF) is replaced with cobalt foam (CF).

The oxygen evolution reaction polarization curve test results (Figure 16) show that the F-NiOOH/NiMoO ₄ /CF catalyst has excellent electrocatalytic activity for the oxygen evolution reaction, and it only needs a 253mV oxygen evolution reaction in 1.0M potassium hydroxide alkali solution. Potential can reach the current density of 10mAcm ^-2 .

Example 6

Synthesis, Structure and Catalytic Properties of F-Ni _1-x Fe _x OOH/NiFe LDH/NF Catalyst

Catalyst preparation:

In the synthesis method of this example, it is similar to that of Example 1, except that the hydroxide/oxide precursor is the only difference.

The oxide precursor was synthesized by the following method: nickel foam (1×4cm ² ) was ultrasonically cleaned with ethanol for 10 minutes, activated with 1M hydrochloric acid solution for 5 minutes and ultrasonically cleaned with deionized water for 10 minutes, together with 36 mL of Ni(NO ₃ ) ₂ · 6H ₂ O (4mmol), Fe(NO ₃ ) ₃ · 9H ₂ O (1mmol), CO(NH ₂ ) ₂ (10mmol) deionized aqueous solution was placed in a water heating ax with a volume of 50mL, and kept at 150°C After 18 hours of treatment, it was naturally cooled to room temperature, and the prepared sample was fully cleaned and then vacuum-dried at 60°C for 2 hours to obtain the oxide precursor NiFe LDH/NF.

The oxygen evolution reaction polarization curve test results (Figure 17) show that the F-Ni _1-x Fe _x OOH/NiFe LDH/NF catalyst has excellent electrocatalytic activity for the oxygen evolution reaction, which is only The current density of 100mA cm ^-2 can be reached with an oxygen evolution overpotential of 260mV.

The above embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. The fluorine-doped non-noble metal electrocatalyst is characterized by comprising an active amorphous layer and a substrate, wherein the active amorphous layer is distributed on the surface of the substrate, and the active amorphous layer is fluorine-doped non-noble metal oxyhydroxide.

2. The fluorine doped non-noble metal electrocatalyst according to claim 1, wherein the non-noble metal in the fluorine doped non-noble metal oxyhydroxide is at least one of Fe, co and Ni;

the base body is non-noble metal oxide or metal hydroxide, and the non-noble metal is at least one of Fe, co, ni and Mo.

3. The fluorine doped non-noble metal electrocatalyst according to claim 1, wherein the thickness of the active amorphous layer is from 2 to 5 nm; the active amorphous layer is obtained by the conversion of a substrate under electrochemical anodic oxidation in an alkaline solution containing fluoride ions.

4. A fluorine doped non-noble metal electrocatalyst according to claim 1, wherein the matrix is present in the form of nanoplates;

the electrocatalyst further comprises a support on which the substrate is supported; the carrier is one of foam metal, metal mesh, ion exchange resin and molecular sieve.

5. The fluorine-doped non-noble metal electrocatalyst according to claim 1, wherein the substrate is Ni (OH) ₂ 、Co(OH) ₂ Or NiMoO ₄ 。

6. A process for the preparation of a fluorine doped non-noble metal electrocatalyst according to any one of claims 1 to 5, comprising the steps of:

(1) Adding a carrier material into a solution containing non-noble metal salt, carrying out hydrothermal reaction, growing a nano-structure catalyst precursor on the surface of the carrier material,

(2) And (2) electrochemically anodizing the catalyst precursor in the step (1) in an alkaline solution containing fluoride ions to obtain the fluorine-doped non-noble metal electrocatalyst.

7. The method according to claim 6, wherein the non-noble metal salt of step (1) comprises at least one of a halide and an oxysalt of a non-noble metal, the non-noble metal comprising at least one of Fe, ni, co, and Mo; the carrier material is selected from one of foamed metal, metal mesh, ion exchange resin and molecular sieve.

8. The method according to claim 6, wherein the concentration of the non-noble metal salt in the step (1) is 0.01 to 0.1M; the solvent of the solution is water; the temperature of the hydrothermal reaction is 120-180 ℃; the time of the hydrothermal reaction is 6-12 hours.

9. The method according to claim 6, wherein the fluoride ion in the step (2) is at least one of sodium fluoride and potassium fluoride; the time of the electrochemical anode oxidation is 0.5 to 1.5h, and the current density is 5 to 20mA cm ^-2 The concentration of the fluorine ions is 0.25-0.75M; the concentration of the alkaline solution is 0.5M-1.5M.

10. Use of a fluorine doped non-noble metal electrocatalyst according to any one of claims 1 to 5 for the electrocatalytic decomposition of oxygen from water.

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