Preparation Method and Application of Halogen / Boron Co-Doped Carbon-Coated Metal Catalytic Material

Abstract

The present invention provides a method for preparing a halogen / boron co-doped carbon-coated metal catalytic material. The method is as follows: After mixing a metal halide with a tetraphenylborate, a reaction precursor is obtained through ball milling; under the atmosphere of a protective gas, the reaction precursor is subjected to pyrolysis treatment to obtain a pyrolyzed product; the conditions for the pyrolysis treatment are: under the condition that the reaction pressure is 50 kPa to 300 kPa, the temperature is raised from room temperature to 600 °C to 1500 °C at a heating rate of 1 °C / min to 10 °C / min, then thermally pyrolyzed at a constant temperature for 1 h to 10 h, and then naturally cooled to room temperature; the pyrolyzed product is successively washed with ethanol, an aqueous hydrochloric acid solution, and deionized water, then centrifuged and separated, and then vacuum dried to obtain the halogen / boron co-doped carbon-coated metal catalytic material. It also provides applications in the reactions of deuterium evolution at the cathode, oxygen evolution at the anode, and overall deuterium water electrolysis of heavy water electrolysis. The catalytic material of the present invention exhibits excellent catalytic activity for both the cathode and anode reactions of electrochemical overall water splitting.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and particularly relates to a preparation method and application of a halogen / boron co-doped carbon-coated metal catalytic material. Background Art

[0002] Converting sustainable energy into green hydrogen energy through the electrocatalytic water splitting process for storage and utilization is one of the important ways for the future development of energy technology. However, this approach is still limited by the high overpotentials of the anode and cathode of the electrolytic cell and the price of commercial noble metal catalytic materials, resulting in high operating costs. In addition, deuterium, as one of the two isotopes of hydrogen, is extremely similar to hydrogen in properties but its content in nature is only 150 ppm. Deuterium gas composed of two deuterium atoms has important applications in the nuclear industry, communication, and integrated circuit fields, and is usually prepared by electrocatalytic decomposition of heavy water.

[0003] A reasonable catalyst structure can reduce the energy consumption of this process and improve the preparation efficiency, and a low-cost source of catalytic materials can significantly reduce the overall cost. Transition metal-based materials have good intrinsic catalytic activity, but unsupported metals (alloys) are prone to agglomeration and corrosion, resulting in insufficient exposure of active sites and poor stability of such materials. To solve the above problems, carbon materials are widely used as carriers for transition metal-based materials to improve their structural stability, conductivity, and reduce the metal usage and aggregation degree. However, there are few active sites on these chemically inert sp2 carbon carriers, and the outer carbon structure blocks the accessibility of internal metal active sites to a certain extent. Reasonably designing the carbon carrier itself and the composite metal structure through a simple and feasible synthesis strategy to improve the catalytic activity of the material and reduce the overall energy consumption of the reaction are the key and difficult problems in the fields of electrocatalytic water splitting and electrocatalytic heavy water splitting. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a preparation method and application of a halogen / boron co-doped carbon-coated metal catalytic material in view of the above-mentioned deficiencies of the prior art. The halogen / boron co-doped carbon-coated metal catalytic material prepared by this method is a spherical composite material wrapped by porous carbon, and can be used as an electrochemically hydrogen evolution, oxygen evolution, and overall water splitting catalytic material, as well as an application for electrolyzing heavy water cathode (deuterium evolution), anode (oxygen evolution), and overall heavy water splitting reaction.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: A preparation method of a halogen / boron co-doped carbon-coated metal catalytic material, and the method is as follows:

[0006] S1. After mixing a metal halide and tetraphenylborate, ball milling is carried out to obtain a reaction precursor;

[0007] S2. Under the atmosphere of a protective gas, subject the reaction precursor obtained in S1 to pyrolysis treatment to obtain a pyrolyzed product; the conditions for the pyrolysis treatment are: under a reaction pressure of 50 kPa to 300 kPa, raise the temperature from room temperature to 600 °C to 1500 °C at a heating rate of 1 °C / min to 10 °C / min, then keep it at a constant temperature for pyrolysis for 1 h to 10 h, and then naturally cool to room temperature;

[0008] S3. Wash the pyrolyzed product obtained in S2 successively with ethanol, an aqueous hydrochloric acid solution with a mass fraction of 10%, and deionized water, then perform centrifugal separation, and after vacuum drying, obtain a halogen / boron co-doped carbon-coated metal catalytic material.

[0009] In the present invention, a high-temperature treatment is used for a mixture of tetraphenylborate and metal halide to pyrolyze the tetraphenylborate to generate boron-doped carbon, and the halogen atoms are further doped therein by the reaction of the metal halide with the boron-doped carbon during the pyrolysis process, and at the same time alloy nanoparticles are generated to obtain a halogen / boron co-doped carbon-coated metal catalytic material.

[0010] The advantages of the catalytic material prepared by the present invention are as follows: on the one hand, electron-deficient boron can functionalize the inert carbon structure and endow it with certain catalytic activity; on the other hand, halogen atoms have strong electronegativity, which can promote the electron transfer between them, boron-doped carbon, and the metal coated therein, and optimize the adsorption energy of intermediates during the reaction process; the above two aspects work together to achieve the purpose of reducing the overpotential of the electrolytic water reaction and play a role in saving the energy consumption in the overall process of water decomposition for hydrogen production / deuterium production from heavy water decomposition. In addition, a low-cost transition metal material is used to partially or completely replace the noble metal material to enhance the price advantage of the catalyst.

[0011] Preferably, in S1, the mass ratio of the ball powder is 20:1, and the ball milling time is 30 min to 40 min.

[0012] Preferably, in S1, the molar ratio of the metal halide to the tetraphenylborate is 1:2.

[0013] Preferably, the metal halide is a mixture of nickel chloride hexahydrate and ferrous chloride tetrahydrate with a molar ratio of 2:1.

[0014] Preferably, the tetraphenylborate is sodium tetraphenylborate (C 24 H 20 BNa).

[0015] Preferably, in S1, the particle size of the reaction precursor is 150 nm to 200 nm.

[0016] Preferably, in S2, the protective gas is nitrogen or argon.

[0017] Preferably, the centrifugal speed in S3 is 7000 rpm to 8000 rpm, and the centrifugal time is 5 min to 10 min.

[0018] Preferably, the halogen / boron co-doped carbon-coated metal catalyst material in S3 is a porous spherical composite material with a diameter of 50 nm to 200 nm and a pore size of 2 nm to 20 nm.

[0019] The present invention also provides the use of the halogen / boron co-doped carbon-coated metal catalytic material prepared by the above-mentioned preparation method, and the use of the halogen / boron co-doped carbon-coated metal catalytic material in the cathode deuterium evolution, anode oxygen evolution and complete decomposition of heavy water electrolysis.

[0020] The tetraphenylborate in the present invention may also be potassium tetraphenylborate.

[0021] The metal halide used in the present invention can also be manganese fluoride (MnF2); iron fluoride (FeF2, FeF3); cobalt fluoride (CoF2); nickel fluoride (NiF2); copper fluoride (CuF, CuF2); zinc fluoride (ZnF2); tungsten hexafluoride (WF6); molybdenum hexafluoride (MoF6); ruthenium hexafluoride (RuF6); platinum hexafluoride (PtF6); manganese chloride (MnCl2, MnCl3, MnCl4) and hydrates thereof; iron chloride (FeCl2, FeCl3) and hydrates thereof; cobalt chloride (CoCl2, CoCl3) and hydrates thereof; nickel chloride (NiCl2) and hydrates thereof; copper chloride (CuCl, CuCl2) and hydrates thereof; zinc chloride (ZnCl2) and hydrates thereof; tungsten chloride (WCl2, WCl3, WCl4, WCl5, WCl6); molybdenum chloride (MoC l3, MoCl5); ruthenium chloride (RuCl3) and its hydrates; hexacarbonyl ruthenium chloride (Ru2Cl4(CO)6); iridium chloride (IrCl3) and its hydrates; platinum chloride (PtCl4) and its hydrates; chloroplatinic acid (H2PtCl6) and its hydrates; manganese bromide (MnBr2); iron bromide (FeBr2, FeBr3); cobalt bromide (CoBr2); nickel bromide (NiBr2); copper bromide (CuBr, CuBr2); zinc bromide (ZnBr2); tungsten bromide (WBr2, WBr3, WBr4, WBr5, WBr6); molybdenum bromide (MoBr3, MoBr4); ruthenium bromide (RuBr3) and its hydrates; iridium bromide (IrBr3, IrBr4) and its hydrates; platinum bromide (PtBr2, PtBr4) and its hydrates, one or a combination of two or more thereof.

[0022] The doped halogen of the present invention can also be any one of fluorine, chlorine, and bromine, or a combination of several of them; the carbon-coated metal can also be manganese, iron, cobalt, nickel, copper, zinc, tungsten, molybdenum, ruthenium, iridium, platinum, or an alloy formed by a combination of two or more.

[0023] In step S3 of the present invention, the ethanol used for washing can also be ethanol, water, acetone, isopropanol, and the dilute hydrochloric acid aqueous solution used can also be dilute acetic acid or dilute sulfuric acid.

[0024] The present invention has the following advantages compared with the prior art:

[0025] 1. The halogen / boron co-doped carbon-coated metal catalytic material prepared by the present invention is a spherical composite material wrapped by porous carbon, and can be used as an electrocatalytic hydrogen evolution, oxygen evolution, and overall water splitting catalytic material, as well as an application for the cathode (deuterium evolution), anode (oxygen evolution), and overall heavy water splitting reaction of electrolyzing heavy water.

[0026] 2. The present invention uses the above-mentioned halogen / boron co-doped carbon-coated metal catalytic material or the material prepared by the above-mentioned method as a bifunctional electrocatalytic hydrogen evolution (deuterium evolution), oxygen evolution, overall water splitting, and overall heavy water splitting reaction catalyst. When used as a catalyst for the cathode (hydrogen evolution) reaction of electrolyzing water, a current density of 20 mA cm -2 can be obtained with an overpotential of 210 mV. When used as a catalyst for the anode (oxygen evolution) reaction, a current density of 50 mA cm -2 can be obtained with an overpotential of 290 mV. When used as a catalyst for both the cathode and anode reactions, a current density of 50 mA cm -2 can be obtained by applying a voltage of 1.69 V. In addition, the above-mentioned material also exhibits excellent performance in electrolyzing heavy water. In the cathode (deuterium evolution) reaction in this system, a current density of 20 mA cm -2 can be obtained with only 259 - 261 mV; in the anode (oxygen evolution) reaction, a current density of 50 mA cm -2 can be obtained with only 309 - 312 mV; in the overall heavy water splitting reaction, a current density of 50 mA cm -2 can be obtained with only 1.76 - 1.78 V, which is superior to most electrolyzing water / electrolyzing heavy water catalysts and has a considerable price advantage, showing good application prospects.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0028] Figure 1 is a scanning electron microscope image of the halogen / boron co-doped carbon-coated metal catalytic material prepared in Example 1 of the present invention.

[0029] Figure 2 is a transmission electron microscope image of the halogen / boron co-doped carbon-coated metal catalytic material prepared in Example 1 of the present invention.

[0030] Figure 3 are the XRD curves of the halogen / boron co-doped carbon-coated metal catalytic materials prepared in Example 1 and Comparative Examples 1 - 4.

[0031] Figure 4 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in the hydrogen evolution reaction of electrolyzed water.

[0032] Figure 5 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in the oxygen evolution reaction of electrolyzed water.

[0033] Figure 6 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in overall water splitting.

[0034] Figure 7 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in the deuterium evolution reaction of electrolyzed heavy water.

[0035] Figure 8 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in the oxygen evolution reaction of electrolyzed heavy water.

[0036] Figure 9 Linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 of the present invention in overall heavy water splitting. Detailed implementation mode

[0037] Example 1

[0038] The preparation method of the halogen / boron co-doped carbon-coated metal catalytic material of this example is as follows:

[0039] S1. After mixing 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol), 1.33 g of ferrous chloride tetrahydrate (6.67 mmol) and 3.19 g of nickel chloride hexahydrate (13.33 mmol), and ball milling for 30 min, a reaction precursor with a particle size of 150 nm is obtained; the mass ratio of the ball to the powder during ball milling is 20:1;

[0040] S2. Under the atmosphere of a nitrogen protective gas, the reaction precursor obtained in S1 is subjected to pyrolysis treatment to obtain 3.64 g of pyrolyzed product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 100 kPa, the temperature is raised from room temperature to 900 °C at a heating rate of 5 °C / min, then thermally pyrolyzed at a constant temperature for 2 h, and then naturally cooled to room temperature;

[0041] S3. The pyrolysis products obtained in S2 are successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at 7000 rpm for 10 min, followed by vacuum drying to obtain a halogen / boron co-doped carbon-coated metal catalyst material (chlorine-boron co-doped carbon-coated nickel-iron alloy material), named Fe1Ni2@chlorine-boron-carbon; the halogen / boron co-doped carbon-coated metal catalyst material is a porous spherical composite material with a diameter of 50 nm to 150 nm and a pore size of 2 nm to 20 nm.

[0042] The scanning electron microscope image of Fe1Ni2@chlorine-boron-carbon prepared in this example is as Figure 1 shown, and it is observed that the composite material presents a rough and dispersed flaky structure, and there are also coated spherical nickel-iron alloy particles.

[0043] The transmission electron microscope image of Fe1Ni2@chlorine-boron-carbon prepared in this example is as Figure 1 shown, showing that the prepared catalyst material is evenly dispersed and the particle size is 50 nm to 150 nm.

[0044] In this example, the morphology of the material was studied by means of scanning electron microscopy, transmission electron microscopy, etc. It is characterized by: a porous carbon-wrapped spherical composite material. And the metal phases in it were analyzed by X-ray diffraction technology, and the metal in the multi-metal sample is an alloy.

[0045] This example also provides the application of the halogen / boron co-doped carbon-coated metal catalyst material prepared by the above preparation method, and the application of the halogen / boron co-doped carbon-coated metal catalyst material in the electrolysis of heavy water for cathodic deuterium evolution, anodic oxygen evolution, and overall electrolysis of heavy water reactions.

[0046] The halogen / boron co-doped carbon-coated metal catalyst material prepared by the present invention is used as a bifunctional electrocatalyst for hydrogen (deuterium) evolution, oxygen evolution, overall water splitting, and overall heavy water splitting reactions. The test system is a three-electrode system (Hg / HgO electrode as the reference electrode, graphite rod electrode as the counter electrode, and the working electrode is a rotating disk electrode), and the loading of the working electrode catalyst material is 1.2 mg cm -2 ; the electrolyte is 1.0 M potassium hydroxide solution; the reaction temperature is 298.15 K; the reaction pressure is 1 bar.

[0047] Electrochemical experiments show that: when the material prepared in this example is used as a catalyst for the cathodic (hydrogen evolution) reaction of electrolyzing water, an overpotential of 210 mV can obtain a current density of 20 mA cm -2 ; when used as a catalyst for the anodic (oxygen evolution) reaction, an overpotential of 290 mV can obtain a current density of 50 mA cm -2 ; when used as a catalyst for both the cathode and anode reactions, applying a voltage of 1.69 V can obtain a current density of 50 mA cm -2Current density; additionally, the material also exhibits excellent performance in electrolytic heavy water. In the cathode (deuterium evolution) reaction in this system, only 260 mV is required to obtain a current density of 20 mA cm -2 ; in the anode (oxygen evolution) reaction, only 310 mV is required to obtain a current density of 50 mA cm -2 ; in the overall heavy water electrolysis reaction, only 1.77 V is required to obtain a current density of 50 mA cm -2 . This is better than most electrolytic water / electrolytic heavy water catalysts and has a considerable price advantage, with good application prospects.

[0048] Comparative Example 1

[0049] The preparation method of the chlorine-boron co-doped carbon-coated iron single material in this comparative example is as follows:

[0050] S1. After mixing 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol) and 1.33 g of ferrous chloride tetrahydrate (6.67 mmol), ball milling is carried out for 30 min to obtain a reaction precursor with a particle size of 200 nm; the mass ratio of the ball to the powder in ball milling is 20:1;

[0051] S2. Under the atmosphere of nitrogen protective gas, the reaction precursor obtained in S1 is subjected to pyrolysis treatment to obtain 3.18 g of pyrolyzed product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 100 kPa, the temperature is raised from room temperature to 900 °C at a heating rate of 5 °C / min, then thermally pyrolyzed at a constant temperature for 2 h, and then naturally cooled to room temperature;

[0052] S3. The pyrolyzed product obtained in S2 is successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at a rotation speed of 7000 rpm for 10 min, and then vacuum dried to obtain a chlorine-boron co-doped carbon-coated iron single material, named Fe@chlorine-boron carbon; Fe@chlorine-boron carbon is a blocky porous composite material with a particle size of 100 nm to 200 nm and a pore size of 2 nm to 20 nm.

[0053] In this comparative example, the morphology of the material was studied by means of scanning electron microscopy, transmission electron microscopy, etc., and its characteristics are: a blocky composite material wrapped by porous carbon. And the metal phase in it was analyzed by X-ray diffraction technology, and the metal in the single metal sample is a metal single substance.

[0054] Comparative Example 2

[0055] The preparation method of the chlorine / boron co-doped carbon-coated nickel single material in this comparative example is as follows:

[0056] S1. Mix 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol) with 3.19 g of nickel chloride hexahydrate (13.33 mmol). After ball milling for 30 min, a reaction precursor with a particle size of 200 nm is obtained; the mass ratio of balls to powder for ball milling is 20:1;

[0057] S2. Under the atmosphere of nitrogen protective gas, perform pyrolysis treatment on the reaction precursor obtained in S1 to obtain 3.13 g of pyrolyzed product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 100 kPa, raise the temperature from room temperature to 900 °C at a heating rate of 5 °C / min, then keep it at a constant temperature for pyrolysis for 2 h, and then cool it naturally to room temperature;

[0058] S3. Wash the pyrolyzed product obtained in S2 successively with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, then perform centrifugal separation at a speed of 7000 rpm for 10 min, and then perform vacuum drying to obtain a chlorine / boron co-doped carbon-coated nickel single material, named Ni@chlorine boron carbon; Ni@chlorine boron carbon is a blocky porous composite material with a particle size of 100 nm - 150 nm and a pore size of 5 nm - 15 nm.

[0059] In this comparative example, the morphology of the material was studied by means of scanning electron microscopy, transmission electron microscopy, etc., and its characteristics are: a blocky composite material wrapped by porous carbon. And the metal phase in it was analyzed by X-ray diffraction technology, and the metal in the single metal sample is a metal single substance.

[0060] Comparative Example 3

[0061] The preparation method of the halogen / boron co-doped carbon-coated metal catalytic material in this comparative example is as follows:

[0062] S1. Mix 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol), 0.80 g of ferrous chloride tetrahydrate (4.00 mmol) and 3.80 g of nickel chloride hexahydrate (16.00 mmol). After ball milling for 30 min, a reaction precursor with a particle size of 150 nm is obtained; the mass ratio of balls to powder for ball milling is 20:1;

[0063] S2. Under the atmosphere of nitrogen protective gas, perform pyrolysis treatment on the reaction precursor obtained in S1 to obtain 2.74 g of pyrolyzed product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 100 kPa, raise the temperature from room temperature to 900 °C at a heating rate of 5 °C / min, then keep it at a constant temperature for pyrolysis for 2 h, and then cool it naturally to room temperature;

[0064] S3. The pyrolyzed product obtained in S2 is successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at 7000 rpm for 10 min, followed by vacuum drying to obtain a halogen / boron co-doped carbon-coated metal catalyst material (chlorine / boron co-doped carbon-coated nickel-iron alloy material), named Fe1Ni4@chlorine-boron-carbon; Fe1Ni4@chlorine-boron-carbon is a porous block composite material with a particle size of 20 nm to 150 nm and a pore size of 2 nm to 20 nm.

[0065] In this comparative example, the morphology of the material was studied by means of scanning electron microscopy, transmission electron microscopy, etc. It is characterized by a porous carbon-wrapped block composite material. The metal phases in it were analyzed by X-ray diffraction technology, and the metal in the multi-metal sample is an alloy.

[0066] Comparative Example 4

[0067] The preparation method of the halogen / boron co-doped carbon-coated metal catalyst material in this comparative example is as follows:

[0068] S1. 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol), 0.80 g of ferrous chloride tetrahydrate (4.00 mmol), and 3.80 g of nickel chloride hexahydrate (16.00 mmol) are mixed and then ball-milled for 30 min to obtain a reaction precursor with a particle size of 150 nm; the mass ratio of the ball to the powder in ball-milling is 20:1;

[0069] S2. Under the atmosphere of nitrogen protective gas, the reaction precursor obtained in S1 is pyrolyzed to obtain 2.74 g of pyrolyzed product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 100 kPa, the temperature is raised from room temperature to 900 °C at a heating rate of 5 °C / min, then kept at a constant temperature for pyrolysis for 2 h, and then naturally cooled to room temperature;

[0070] S3. The pyrolyzed product obtained in S2 is successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at 7000 rpm for 10 min, followed by vacuum drying to obtain a halogen / boron co-doped carbon-coated metal catalyst material (chlorine / boron co-doped carbon-coated nickel-iron alloy material), named Fe4N1@chlorine-boron-carbon; Fe4N1@chlorine-boron-carbon is a porous block composite material with a particle size of 50 nm to 100 nm and a pore size of 2 nm to 20 nm.

[0071] In this comparative example, the morphology of the material was studied by means of techniques such as scanning electron microscopy and transmission electron microscopy. Its characteristics are: a bulk composite material wrapped with porous carbon. And the metal phases in it were analyzed by X-ray diffraction technology. The metals in the multi-metal samples are alloys.

[0072] The XRD curves of the halogen / boron co-doped carbon-coated metal catalytic materials prepared in Example 1 and Comparative Examples 1-4 are as Figure 3 shown. The characteristic peaks observed in the prepared Fe@ClBC sample correspond to the standard peaks of metallic Fe (JCPDS No. 01-1262) at 44.6, 64.7, and 82.5°. The prepared Ni@ClBC sample shows three sharp diffraction peaks at 44.5, 51.8, and 75.3°, which correspond to the (111), (200), and (220) phases of highly crystalline metallic Ni (JCPDS No. 04-0850). In addition, the diffraction peaks of the prepared FexNiy@ClBC alloy catalyst were indexed as graphite C (JCPDS No. 41-1487), sodium chloride (JCPDS No. 75-0306), and NiFe alloy (JCPDS No. 38-0419).

[0073] To evaluate the electrocatalytic hydrogen evolution and oxygen evolution performance of the samples, linear sweep voltammetry (LSV) curves of different catalysts were obtained at 25 °C in a 1.0 M KOH solution using a conventional three-electrode system, as Figures 4 - 9 shown, and the details are as follows.

[0074] The linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials prepared in Example 1 and Comparative Examples 1-4 in the electrolytic water hydrogen evolution reaction are as Figure 4 shown. When used as a catalyst for the cathode (hydrogen evolution) reaction of electrolytic water, the overpotential of the optimal catalyst material is 210 mV to obtain a current density of 20 mA cm -2 .

[0075] The linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 in the electrolytic water oxygen evolution reaction are as Figure 5 shown. When used as a catalyst for the anode (oxygen evolution) reaction, the overpotential of the optimal catalyst material is 290 mV to obtain a current density of 50 mA cm -2 .

[0076] The linear sweep voltammetry measurement curve of the halogen / boron co-doped carbon-coated metal catalytic material prepared in Example 1 in overall water splitting is as Figure 6 shown. When used as a catalyst for both the cathode and anode reactions, a voltage of 1.69 V is applied to the optimal catalyst material to obtain a current density of 50 mA cm -2 .

[0077] The linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 in the electrolysis of heavy water for deuterium evolution reaction are as Figure 7 shown. When catalyzing the cathode (deuterium evolution) reaction, the overpotential of the optimal catalyst material is 260 mV to obtain a current density of 20 mA cm -2 .

[0078] The linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 in the electrolysis of heavy water for oxygen evolution reaction are as Figure 8 shown. When catalyzing the anode (oxygen evolution) reaction, the overpotential of the optimal catalyst material is 310 mV to obtain a current density of 50 mA cm -2 .

[0079] The linear sweep voltammetry measurement curves of the halogen / boron co-doped carbon-coated metal catalytic materials obtained in Example 1 and Comparative Examples 1-4 in the overall electrolysis of heavy water are as Figure 8 shown. In the overall electrolysis of heavy water reaction, only 1.77 V is required to obtain a current density of 50 mA cm -2 , which is superior to most electrolytic water / electrolytic heavy water catalysts.

[0080] Example 2

[0081] The preparation method of the halogen / boron co-doped carbon-coated metal catalytic material of this example is as follows:

[0082] S1. After mixing 13.69 g of sodium tetraphenylborate (C 24 H 20 BNa) (40 mmol), 1.33 g of ferrous chloride tetrahydrate (6.67 mmol) and 3.19 g of nickel chloride hexahydrate (13.33 mmol), ball milling for 40 min, a reaction precursor with a particle size of 200 nm is obtained; the mass ratio of the ball to the powder in ball milling is 20:1;

[0083] S2. Under the atmosphere of argon protective gas, the reaction precursor obtained in S1 is subjected to pyrolysis treatment to obtain 2.69 g of pyrolysis product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 300 kPa, the temperature is raised from room temperature to 1500 °C at a heating rate of 10 °C / min, then thermally pyrolyzed at a constant temperature for 10 h, and then naturally cooled to room temperature;

[0084] S3. The pyrolysis product obtained in S2 is successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at 8000 rpm for 5 min, and then vacuum dried to obtain a halogen / boron co-doped carbon-coated metal catalyst material (chlorine-boron co-doped carbon-coated nickel-iron alloy material); the halogen / boron co-doped carbon-coated metal catalyst material is a porous spherical composite material with a diameter of 50 nm to 200 nm and a pore size of 5 nm to 10 nm.

[0085] This example also provides the application of the halogen / boron co-doped carbon-coated metal catalyst material prepared by the above preparation method. The halogen / boron co-doped carbon-coated metal catalyst material exhibits excellent performance in the electrolysis of heavy water. In the cathode (deuterium evolution) reaction in this system, only 261 mV is required to obtain a current density of 20 mA cm -2 ; in the anode (oxygen evolution) reaction, only 312 mV is required to obtain a current density of 50 mA cm -2 ; in the overall electrolysis of heavy water reaction, only 1.78 V is required to obtain a current density of 50 mA cm -2 . It can be applied in the cathode deuterium evolution, anode oxygen evolution, and overall electrolysis of heavy water reactions.

[0086] Example 3

[0087] The preparation method of the halogen / boron co-doped carbon-coated metal catalyst material in this example is as follows:

[0088] S1. 13.69 g of sodium tetraphenylborate (40 mmol), 1.33 g of ferrous chloride tetrahydrate (6.67 mmol), and 3.19 g of nickel chloride hexahydrate (13.33 mmol) are mixed and then ball milled for 10 min to obtain a reaction precursor with a particle size of 170 nm; the mass ratio of the ball to the powder in the ball milling is 20:1;

[0089] S2. Under the atmosphere of nitrogen or argon protective gas, the reaction precursor obtained in S1 is pyrolyzed to obtain 2.68 g of pyrolysis product; the conditions of the pyrolysis treatment are: under the condition of a reaction pressure of 50 kPa, the temperature is raised from room temperature to 600 °C at a heating rate of 1 °C / min, then thermally pyrolyzed at a constant temperature for 1 h, and then naturally cooled to room temperature;

[0090] S3. The pyrolysis product obtained in S2 is successively washed with ethanol, 10% hydrochloric acid aqueous solution, and deionized water, and then centrifuged at 7000 rpm for 7 min, and then vacuum dried to obtain a halogen / boron co-doped carbon-coated metal catalyst material (chlorine-boron co-doped carbon-coated nickel-iron alloy material); the halogen / boron co-doped carbon-coated metal catalyst material is a porous spherical composite material with a diameter of 80 nm to 200 nm and a pore size of 2 nm to 15 nm.

[0091] This embodiment also provides the application of the halogen / boron co-doped carbon-coated metal catalytic material prepared by the above preparation method. The halogen / boron co-doped carbon-coated metal catalytic material exhibits excellent performance in the electrolysis of heavy water. In the cathode (deuterium evolution) reaction in this system, a current density of 20 mA cm -2 can be obtained with only 259 mV; in the anode (oxygen evolution) reaction, a current density of 50 mA cm -2 can be obtained with only 308 mV; in the overall electrolysis of heavy water reaction, a current density of 50 mA cm -2 can be obtained with only 1.76 V. It can be applied in the deuterium evolution at the cathode, oxygen evolution at the anode and overall electrolysis of heavy water reactions in the electrolysis of heavy water.

[0092] The metal halides used in the present invention may also be manganese fluoride (MnF2); iron fluoride (FeF2, FeF3); cobalt fluoride (CoF2); nickel fluoride (NiF2); copper fluoride (CuF, CuF2); zinc fluoride (ZnF2); tungsten hexafluoride (WF6); molybdenum hexafluoride (MoF6); ruthenium hexafluoride (RuF6); platinum hexafluoride (PtF6); manganese chloride (MnCl2, MnCl3, MnCl4) and its hydrates; iron chloride (FeCl2, FeCl3) and its hydrates; cobalt chloride (CoCl2, CoCl3) and its hydrates; nickel chloride (NiCl2) and its hydrates; copper chloride (CuCl, CuCl2) and its hydrates; zinc chloride (ZnCl2) and its hydrates; tungsten chloride (WCl2, WCl3, WCl4, WCl5, WCl6); molybdenum chloride (MoCl3, MoCl5); ruthenium chloride (RuCl3) and its hydrates; ruthenium carbonyl chloride (Ru2Cl4(CO)6); iridium chloride (IrCl3) and its hydrates; platinum chloride (PtCl4) and its hydrates; chloroplatinic acid (H2PtCl6) and its hydrates; manganese bromide (MnBr2); iron bromide (FeBr2, FeBr3); cobalt bromide (CoBr2); nickel bromide (NiBr2); copper bromide (CuBr, CuBr2); zinc bromide (ZnBr2); tungsten bromide (WBr2, WBr3, WBr4, WBr5, WBr6); molybdenum bromide (MoBr3, MoBr4); ruthenium bromide (RuBr3) and its hydrates; iridium bromide (IrBr3, IrBr4) and its hydrates; platinum bromide (PtBr2, PtBr4) and its hydrates, or a combination of two or more of them.

[0093] The tetraphenylborate in the present invention may also be potassium tetraphenylborate.

[0094] The ethanol used for washing in step S3 of the present invention may also be ethanol, water, acetone, isopropyl alcohol, and the dilute hydrochloric acid aqueous solution used may also be dilute acetic acid or dilute sulfuric acid.

[0095] The halogen doping in the present invention can also be any one or a combination of several of fluorine, chlorine, and bromine; the carbon-coated metal can also be an alloy formed by a single element of manganese, iron, cobalt, nickel, copper, zinc, tungsten, molybdenum, ruthenium, iridium, platinum or a combination of two or more of them.

[0096] The present invention conducts a morphological study on the material by means of technical means such as scanning electron microscopy and transmission electron microscopy, and is characterized by: a spherical composite material wrapped by porous carbon. And the metal phases therein are analyzed by X-ray diffraction technology, and it is found that the metal in the single-metal sample is a metal element, and the metal in the multi-metal sample is an alloy.

[0097] As described above, it is only a preferred embodiment of the present invention and does not impose any limitation on the present invention. Any simple modification, change, and equivalent change made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a halogen / boron co-doped carbon-coated metal catalytic material, characterized in that, The method is as follows: S1. After mixing the metal halide and tetraphenyl borate and then ball-milling, a reaction precursor is obtained; the molar ratio of the metal halide to the tetraphenyl borate in S1 is 1:

2. S2. Under the atmosphere of a protective gas, the reaction precursor obtained in S1 is subjected to pyrolysis treatment to obtain a pyrolyzed product; the conditions of the pyrolysis treatment are as follows: under the condition that the reaction pressure is 50 kPa to 300 kPa, the temperature is raised from room temperature to 600 °C to 1500 °C at a heating rate of 1 °C / min to 10 °C / min, then thermally pyrolyzed at a constant temperature for 1 h to 10 h, and then naturally cooled to room temperature. S3. The pyrolyzed product obtained in S2 is successively washed with ethanol, a hydrochloric acid aqueous solution with a mass fraction of 10%, and deionized water, then centrifuged and separated, and then vacuum dried to obtain a halogen / boron co-doped carbon-coated metal catalytic material.

2. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, characterized in that In S1, the mass ratio of the ball to the powder in ball-milling is 20:1, and the ball-milling time is 30 min to 40 min.

3. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, wherein, The metal halide is a mixture of nickel chloride hexahydrate and ferrous chloride tetrahydrate with a molar ratio of 2:

1.

4. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, characterized in that, The tetraphenyl borate is sodium tetraphenyl borate.

5. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, wherein, In S1, the particle size of the reaction precursor is 150 nm to 200 nm.

6. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, characterized in that, The protective gas in S2 is nitrogen or argon.

7. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, characterized in that In S3, the rotation speed of centrifugation is 7000 rpm to 8000 rpm, and the centrifugation time is 5 min to 10 min.

8. The preparation method of a halogen / boron co-doped carbon-coated metal catalytic material according to claim 1, characterized in that, In S3, the halogen / boron co-doped carbon-coated metal catalytic material is a porous spherical composite material with a diameter of 50 nm to 200 nm and a pore diameter of 2 nm to 20 nm.

9. Use of a halogen / boron co-doped carbon-coated metal catalytic material prepared by the preparation method according to any one of claims 1-8, characterized in that, Application of the halogen / boron co-doped carbon-coated metal catalytic material in the reactions of deuterium evolution at the cathode, oxygen evolution at the anode, and overall decomposition of heavy water in the electrolysis of heavy water.

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