CN117174920A - Preparation method and application of a heterostructure ruthenium cobalt boron-based oxide catalyst - Google Patents

Abstract

The invention belongs to the technical field of catalysts and their preparation, and relates to a preparation method and application of a heterostructure ruthenium-cobalt-boron-based oxide catalyst. The preparation method includes: 1) Preparing Co-B precursor: According to the molar ratio of cobalt element to boron element Weigh the cobalt salt and borohydride respectively at a ratio of 1:2, and obtain the Co-B precursor through dissolution, stirring, precipitation, separation and drying; 2) Preparation of Ru-Co-B-based oxide catalyst: According to the ruthenium element and cobalt The molar ratio of the elements is 1: (4-16). The ruthenium salt and Co-B precursor are weighed respectively, and after mixing, grinding, and plasma technology treatment, the Ru-Co-B-based oxide catalyst is obtained. The present invention uses plasma technology to prepare a heterostructure ruthenium-cobalt-boron-based oxide catalyst. The preparation method is simple, easy to operate, and can be prepared on a large scale; and the prepared catalyst has high activity, and can improve battery discharge performance when used in fuel cells.

Description

Preparation method and application of a heterostructure ruthenium cobalt boron-based oxide catalyst

Technical field

The invention belongs to the technical field of catalysts and their preparation, and relates to a preparation method and application of a heterostructure ruthenium cobalt boron-based oxide catalyst.

Background technique

Fuel cells are efficient and clean electrochemical generating devices that convert the chemical energy of fuels such as hydrogen, methanol, ethanol, hydrocarbons, and borohydrides into electrical energy. They have the advantages of high efficiency and environmental friendliness. Fuel cells are considered the most promising energy conversion strategy to achieve energy sustainability.

At present, fuel cell technology has made great progress. However, because most catalysts are composed of precious metals, especially Pt metal, the large-scale application of fuel cells is still limited due to problems such as expensive precious metals and limited reserves. On the road to commercialization of low-temperature fuel cells (such as proton exchange membrane fuel cells (PEMFC)), methanol fuel cells (DMFC), and borohydride fuel cells (DBFC), the durability and cost of fuel cells are the key to fuel cell energy. There are two main challenges to long-term development and commercialization. Therefore, by reducing the content of precious metals in electrode components, battery costs can be directly reduced. However, due to the reduction in content, battery performance and long-term stability are affected.

In recent years, the following two approaches have been used to reduce catalyst costs and improve catalyst performance: (1) developing platinum alloy catalysts; (2) developing non-platinum electrocatalysts; although the above approaches can achieve advantages in cost and performance, However, there are the following problems: At present, the synthesis method of this type of fuel cell catalyst is mainly conventional chemical synthesis or high-temperature treatment. For example, the literature Molten salt assisted to synthesize molybdenumeruthenium boride for hydrogen generation in wide pH range mentions the use of melting Method, mix the prepared molybdenum pentachloride, sodium chloride, potassium chloride, amorphous boron powder and ruthenium trichloride together, grind them until they become powder, then place the above powder in a tube furnace and heat Finally, the nanomaterial Mo-Ru-B was obtained. Literature Ultrafineamorphous Co-WB alloy as the anode catalyst for a direct borohydride fuel cell uses chemical reduction method to prepare ultrafine amorphous Co-WB alloy. Synthesized by chemical reduction of cobalt chloride (CoCl ₂ ) and sodium tungstate (Na ₂ WO ₄ ) with potassium borohydride solution. Different volumes _{of CoCl2} and _Na2WO4 solutions were mixed together to adjust the tungsten content in the sample. Then add the KBH ₄ /KOH solution dropwise into the mixed solution under magnetic stirring, then add potassium borohydride to release hydrogen, stir to obtain a black precipitate, filter it and wash it with distilled water to obtain Co-WB; Patent CN 105702971A introduces A core-shell gold@cobalt-boron catalyst for fuel cells. Prepare a mixed solution of cobalt salt and gold salt, dissolve borohydride in deionized water to prepare a borohydride solution, then add hydroxide to the borohydride solution, and combine the borohydride-hydroxide The mixed solution is added to the mixed solution of cobalt salt and gold salt at a certain speed. After no gas is generated during the reaction, the reaction material is continued to be stirred and filtered to obtain precipitation, thereby obtaining a core-shell gold@cobalt-boron catalyst. Patent CN201210120922.7 introduces a carbon-supported core-shell copper-palladium-platinum catalyst for fuel cells and its preparation method. This method uses a two-step reduction method, that is, first reducing the low-activity metal, and then reducing the active precious metal. By controlling the temperature and pH value of the reaction, the precious metal is deposited on the surface of the non-precious metal, and is supplemented by a dealloying step to form a core. Shell catalyst.

The above-mentioned methods have problems such as complex synthesis processes and high energy consumption, which make it difficult to achieve large-scale production in the long run.

Contents of the invention

In order to solve the technical problem of complicated synthesis process of existing fuel cell catalysts, the present invention provides a preparation method and application of a heterostructure ruthenium cobalt boron-based oxide catalyst.

In order to achieve the above purpose, the present invention uses plasma technology to prepare a heterostructure ruthenium cobalt boron-based oxide catalyst. The preparation method is simple, easy to operate, and can be prepared on a large scale; and the prepared catalyst has high activity and can be used in fuel cells to improve battery performance. Discharge performance. The technical solutions used in the present invention are specifically:

A method for preparing a heterostructure ruthenium-cobalt-boron-based oxide catalyst, which is characterized by comprising the following steps:

1) Preparation of Co-B precursor

Weigh the cobalt salt and boron hydride respectively according to the molar ratio of cobalt element to boron element 1:2, and obtain the Co-B precursor through dissolution, stirring, precipitation, separation and drying;

2) Preparation of Ru-Co-B based oxide catalyst

Weigh the ruthenium salt and Co-B precursor respectively according to the molar ratio of ruthenium element to cobalt element 1: (4-16), and obtain the Ru-Co-B catalyst after mixing, grinding, and plasma technology treatment.

It is further limited that in step 2), the conditions for plasma technology treatment are: voltage 40V-70V, treatment time 5min-20min, and temperature normal temperature.

It is further limited that in step 2), the ruthenium salt is anhydrous ruthenium trichloride.

To further limit, said step 1) specifically includes the following steps:

1.1) Dissolve the weighed cobalt salt in water to obtain a cobalt salt solution;

1.2) Dissolve the weighed borohydride in water to obtain a borohydride solution;

1.3) Add the borohydride solution dropwise to the cobalt salt solution, stir until the reaction is complete, leave to settle, filter, separate and dry to obtain the Co-B precursor.

It is further limited that in step 1.1), the cobalt salt is cobalt chloride hexahydrate, and the concentration of the cobalt salt solution is 0.015 mol/L.

It is further limited that in step 1.2), the borohydride is potassium borohydride, and the concentration of the potassium borohydride solution is 0.03 mol/L.

It is further limited that in the step 1.3), the dropping speed is 1mL/min~2mL/min; the drying conditions are: vacuum degree 80Pa-100Pa, temperature 60℃~120℃, time 6h-12h.

A method for preparing a heterostructure ruthenium cobalt boron based oxide catalyst. The prepared ruthenium cobalt boron based oxide catalyst is a core-shell-lamellar mosaic type heterostructure.

An application of the ruthenium cobalt boron-based oxide catalyst as an anode catalyst in a borohydride fuel cell.

It is further limited that the maximum power density of the borohydride fuel cell is 143.12mW·cm ^-2 ~ 206.35mW·cm ^-2 .

Compared with the prior art, the beneficial effects of the present invention are:

1. The present invention uses a combination of plasma technology to prepare the catalyst. Compared with the traditional chemical synthesis method, the method is simple, easy to operate, and can achieve large-scale production.

2. The present invention adopts low-temperature plasma technology and the temperature is normal temperature. Compared with the high-temperature treatment in traditional chemical methods, the energy consumption is reduced.

3. The preparation method provided by the present invention firstly grinds the reactants thoroughly and mixes them evenly, and then uses low-temperature plasma technology to generate a high-voltage electric field. Under the action of the high-voltage electric field, the reactants are bombarded into particles such as ions, atoms or free radicals, so that the reactants The structure changes and presents a core-shell-lamellar mosaic heterostructure. The prepared catalyst is assembled in a battery, which can greatly improve the performance of the catalyst and has excellent electrochemical performance.

4. The ruthenium cobalt boron-based oxide catalyst prepared by the present invention is a core-shell-lamellar mosaic heterostructure. Compared with the spherical, core-shell structure or hollow structure reported in the existing literature, the catalyst of this structure has low cost and High activity; the fuel cell assembled with carbon-supported cerium oxide (CeO ₂ /C) as the cathode catalyst of the direct borohydride fuel cell DBFC and Ru-Co-B as the anode catalyst, the maximum power density of the fuel cell was measured to reach 143.12mW·cm ^-2 ~ 206.35mW·cm ^-2 , the fuel cell discharge performance is better.

4. The catalyst prepared by the present invention is composed of ruthenium, cobalt and boron, and the molar ratio of ruthenium element, cobalt element and boron element is 1:(4-16):(8-32), and the molar fraction of ruthenium element is 9.09% , the amount of precious metals used has been greatly reduced, and the platinum content in current platinum-based catalysts with good properties is about 10%, and the cost of ruthenium is the lowest among platinum group metals, and the price is far lower than that of platinum, making the cost of fuel cells significantly higher. This will help promote the development of fuel cells.

Description of drawings

Figure 1 is a scanning electron microscope image of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention when magnified 150,000 times;

Figure 2 is a scanning electron microscope image of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention when magnified 50,000 times;

Figure 3 is a scanning electron microscope image of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention when magnified 200,000 times;

Figure 4 is a scanning electron microscope image of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention when magnified 100,000 times;

Figure 5 is an EDS spectrum of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention;

Figure 6 is the XRD spectrum of the Ru-Co-B-based oxide catalyst prepared in Examples 1 to 4 of the present invention;

Figure 7 is a power performance diagram of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention as an anode catalyst for a direct borohydride fuel cell, respectively compared with commercial Pt-Ru/C, commercial Pt/C, and chemically prepared Comparison of battery performance of Ru-Co-B and CoB catalysts as anodes of direct borohydride fuel cells;

Figure 8 is a constant current discharge test of the Ru-Co-B-based oxide catalyst prepared in Example 1 of the present invention.

Detailed ways

The technical solution protected by the present invention will now be described in detail with reference to the accompanying drawings and examples.

A method for preparing a heterostructure ruthenium-cobalt-boron-based oxide catalyst, including the following steps.

1) Preparation of Co-B precursor

Weigh the cobalt salt and boron hydride respectively according to the molar ratio of cobalt element to boron element 1:2, and obtain the Co-B precursor through dissolution, stirring, precipitation, separation and drying.

The Co-B precursor in this step specifically includes the following steps:

1.1) Dissolve the weighed cobalt salt in water to obtain a cobalt salt solution.

Preferably, the cobalt salt is cobalt chloride hexahydrate, but the cobalt salt can also use anhydrous cobalt chloride, cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, etc., and the concentration of the cobalt salt solution is 0.015 mol/L.

1.2) Dissolve the weighed borohydride in water to obtain a borohydride solution.

Preferably, the borohydride is potassium borohydride, but the borohydride can also be sodium borohydride, lithium borohydride, etc., wherein the concentration of the borohydride solution is 0.03 mol/L.

1.3) Add the borohydride solution dropwise to the cobalt salt solution, stir until the reaction is complete, leave to settle, filter, separate and dry to obtain the Co-B precursor.

In this step, the dropping speed is 1mL/min~2mL/min; the drying conditions are: vacuum degree 80Pa-100Pa, temperature 60℃~120℃, time 6h-12h.

2) Preparation of Ru-Co-B based oxide catalyst

Weigh the ruthenium salt and Co-B precursor respectively according to the molar ratio of ruthenium element to cobalt element 1: (4-16), and obtain the Ru-Co-B-based oxide catalyst after mixing, grinding, and plasma technology treatment.

Specifically, the molar ratio of the ruthenium salt is deduced based on the molar ratio of cobalt element to boron element in the Co-B precursor of 1:2 and the amount of cobalt salt material prepared and configured as a standard.

In this step, the plasma technology treatment conditions are: voltage 40V-70V, treatment time 5min-20min, and temperature at normal temperature.

Preferably, the ruthenium salt is anhydrous ruthenium trichloride, but the ruthenium salt can also be water-soluble ruthenium trichloride (RuCl ₃ ·xH ₂ O), ruthenium nitrate, ruthenium sulfate, ruthenium acetate, etc.

The ruthenium cobalt boron-based oxide catalyst prepared by the above method of the present invention has a core-shell-lamellar mosaic heterostructure and can be used as an anode catalyst in a borohydride fuel cell. When CeO ₂ /C is used as a cathode catalyst, the assembled The maximum power density of the fuel cell is 143.12mW·cm ^-2 ~ 206.35mW·cm ^-2 , and the discharge performance is better.

The preparation method of the present invention and the performance advantages of the catalyst are described below with several sets of specific examples.

Example 1

The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst in this embodiment includes the following steps.

1) Preparation of Co-B precursor

1.1) Prepare cobalt salt solution: Weigh 0.9137g cobalt chloride hexahydrate, dissolve it in deionized water, and dilute it to a 250 mL volumetric flask to obtain a cobalt chloride hexahydrate solution with a concentration of 0.015 mol/L.

1.2) Prepare potassium borohydride solution: According to the standard that the molar ratio of cobalt element to boron element is 1:2, weigh 0.4142g potassium borohydride, dissolve potassium borohydride in deionized water, and adjust the volume to a 250mL volumetric flask. Prepare a potassium borohydride solution with a concentration of 0.03mol/L.

1.3) Preparation of Co-B precursor: Slowly drop 0.03 mol/L, 250 mL potassium borohydride solution into 0.015 mol/L, 250 mL cobalt chloride hexahydrate solution at a dropping speed of 1 mL/min, and stir continuously until When no bubbles emerge, the reaction is complete. Leave it to settle for half an hour, then filter it and dry it in a vacuum drying oven with a vacuum degree of 80 Pa and 60°C for 12 hours. Finally, the Co-B precursor is obtained.

2) Preparation of Ru-Co-B based oxide catalyst

According to the standard that the molar ratio of ruthenium element to cobalt element is 1:8, weigh 0.1g anhydrous ruthenium trichloride; according to the standard that the mass ratio of Co-B precursor to anhydrous ruthenium trichloride is 1:1, Weigh 0.1g Co-B precursor, mix the precursor with the weighed anhydrous ruthenium trichloride and grind it thoroughly, then put the mixed solid particles into a low-temperature plasma device, in an air-state atmosphere, at a voltage of 50V , energized for 10 minutes, and finally the Ru-Co-B catalyst was obtained.

In this embodiment, the positive and negative electrodes of the low-temperature plasma device are made of conductive metal materials such as stainless steel, copper, aluminum, and iron.

The performance of the Ru-Co-B-based oxide catalyst prepared in this example was characterized.

1. SEM scans of the catalyst at different magnifications, as shown in Figures 1 to 4, which are the SEM scans corresponding to 150,000 times, 50,000 times, 200,000 times and 100,000 times respectively.

The instrument used for SEM scanning is a scanning electron microscope Hitachi SU8230, which is carried out under cold field emission and vacuum conditions in the transition chamber.

It can be seen from Figures 1 to 4 that the Ru-Co-B-based oxide synthesized according to Example 1 is a core-shell-lamellar mosaic type, and the morphology is uniform and nanoscale. It can be seen that the catalyst prepared by plasma technology is a nanocatalyst with a heterogeneous structure. It is different from the load and wrapping structure prepared by existing methods. The structure has undergone major changes. Due to this core-shell -Layered mosaic heterostructure greatly improves the performance of the catalyst, which is significantly better than catalysts prepared by conventional methods.

2. EDS energy spectrum chart

The instrument used by EDS is the American FEI Talos F200x, which is tested under vacuum conditions and under electron beam bombardment conditions.

From Figure 5, we can see the distribution of the three elements Ru, Co, and B, and it can be seen that the three elements are well doped together.

3. XRD spectrum

The instrument used for XRD is the RIGAKU SMARTLAB diffractometer, which is carried out under the scanning conditions of a scanning angle of 10°-80° and a scanning speed of 10°/min.

It can be seen from Figure 6 that the XRD patterns of Ru-Co-B-based oxides with different molar ratios, when 2θ=35°, the three elements are respectively CoO, RuO ₂ and B ₂₀ H ₂₆ O A heterogeneous structure is formed, and the diffraction peaks of the three elements Co, Ru, and B are consistent with their standard peaks (JCPDS NO.42-1300, JCPDS NO.43-1027, JCPDS NO.22-0118), indicating that through the plasma Finally, a Ru-Co-B-based oxide heterostructure catalyst was successfully prepared.

4. Battery performance

The Ru-Co-B-based oxide prepared in this example was used as the anode catalyst of the borohydride fuel cell DBFC, and CeO ₂ /C was used as the cathode catalyst to assemble a borohydride fuel cell. The discharge performance of a single DBFC was passed by the battery test system ( Neware Technology Limited from Shenzhen, China) conducted tests by introducing oxygen at room temperature, and found that the maximum power density of the fuel cell reached 143.12mW·cm ^-2 .

Example 2

The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst in this embodiment includes the following steps.

1) Preparation of Co-B precursor

1.1) Prepare cobalt salt solution: Weigh 0.9137g cobalt chloride hexahydrate, dissolve it in deionized water, and dilute it to a 250 mL volumetric flask to obtain a cobalt chloride hexahydrate solution with a concentration of 0.015 mol/L.

1.2) Prepare potassium borohydride solution: According to the standard that the molar ratio of cobalt element to boron element is 1:2, weigh 0.4142g potassium borohydride, dissolve potassium borohydride in deionized water, and adjust the volume to a 250mL volumetric flask. Prepare a potassium borohydride solution with a concentration of 0.03mol/L.

1.3) Preparation of Co-B precursor: Slowly drop 0.03 mol/L, 250 mL potassium borohydride solution into 0.015 mol/L, 250 mL cobalt chloride hexahydrate solution, with a dropping speed of 2 mL/min, and stir continuously until there is no more When bubbles appear, the reaction is complete. Leave it to settle for half an hour. Then filter it and dry it in a vacuum drying oven with a vacuum of 90 Pa and 80°C for 10 hours. Finally, the Co-B precursor is obtained.

2) Preparation of Ru-Co-B based oxide catalyst

According to the standard that the molar ratio of ruthenium element to cobalt element is 1:9, weigh 0.0885g anhydrous ruthenium trichloride; according to the standard that the mass ratio of Co-B precursor to anhydrous ruthenium trichloride is 1:1, Weigh 0.0885g Co-B precursor, mix the precursor with the weighed anhydrous ruthenium trichloride and grind it fully, then put the mixed solid particles into a low-temperature plasma device, in an air-state atmosphere, at a voltage of 50V , energized for 10 minutes, and finally a Ru-Co-B-based oxide catalyst was obtained.

Characterize the Ru-Co-B-based oxide catalyst prepared in this example.

1. XRD spectrum

The XRD physical characterization results of the product prepared in this example are the same as those in Example 1.

2. Battery performance

The Ru-Co-B-based oxide prepared in this example was used as the anode catalyst of the borohydride fuel cell DBFC, and CeO ₂ /C was used as the cathode catalyst to assemble a borohydride fuel cell. It was measured that the maximum power density of the fuel cell reached 165.16 mW·cm ^-2 .

Example 3

The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst in this embodiment includes the following steps.

1) Preparation of Co-B precursor

1.1) Prepare cobalt salt solution: Weigh 0.9137g cobalt chloride hexahydrate, dissolve it in deionized water, and dilute it to a 250mL volumetric flask to obtain a cobalt chloride hexahydrate solution with a concentration of 0.015 mol/L;

1.2) Prepare potassium borohydride solution: According to the standard that the molar ratio of cobalt element to boron element is 1:2, weigh 0.4142g potassium borohydride, dissolve potassium borohydride in deionized water, and adjust the volume to a 250mL volumetric flask. Prepare a potassium borohydride solution with a concentration of 0.03mol/L;

1.3) Preparation of Co-B precursor: Slowly drop 0.03 mol/L, 250 mL potassium borohydride solution into 0.015 mol/L, 250 mL cobalt chloride hexahydrate solution, with a dropping speed of 1 mL/min, and stir continuously until there is no more When bubbles appear, the reaction is complete. Leave it to settle for half an hour. Then filter it and dry it in a vacuum drying oven with a vacuum of 100Pa and 100°C for 8 hours. Finally, the Co-B precursor is obtained;

2) Preparation of Ru-Co-B based oxide catalyst

According to the standard that the molar ratio of ruthenium element to cobalt element is 1:10, weigh 0.0798g anhydrous ruthenium trichloride; according to the standard that the mass ratio of Co-B precursor to anhydrous ruthenium trichloride is 1:1, Weigh 0.0798g Co-B precursor, mix the precursor with the weighed anhydrous ruthenium trichloride and grind it fully, then put the mixed solid particles into a low-temperature plasma device, in an air-state atmosphere, at a voltage of 50V , energized for 10 minutes, and finally a Ru-Co-B-based oxide catalyst was obtained.

Characterize the Ru-Co-B-based oxide catalyst prepared in this example.

1. XRD spectrum

The XRD physical characterization results of the product prepared in this example are the same as those in Example 1.

2. Battery performance

The Ru-Co-B-based oxide prepared in this example was used as the anode catalyst of the borohydride fuel cell DBFC, and CeO ₂ /C was used as the cathode catalyst to assemble a borohydride fuel cell. It was measured that the maximum power density of the fuel cell reached 206.35 mW·cm ^-2 .

Example 4

The preparation method of the heterostructure ruthenium cobalt boron catalyst in this embodiment includes the following steps.

1) Preparation of Co-B precursor

1.1) Prepare cobalt salt solution: Weigh 0.9137g cobalt chloride hexahydrate, dissolve it in deionized water, and dilute it to a 250mL volumetric flask to obtain a cobalt chloride hexahydrate solution with a concentration of 0.015 mol/L;

1.2) Prepare potassium borohydride solution: According to the standard that the molar ratio of cobalt element to boron element is 1:2, weigh 0.4142g potassium borohydride, dissolve potassium borohydride in deionized water, and adjust the volume to a 250mL volumetric flask. Prepare a potassium borohydride solution with a concentration of 0.03mol/L;

1.3) Preparation of Co-B precursor: Slowly drop 0.03 mol/L, 250 mL potassium borohydride solution into 0.015 mol/L, 250 mL cobalt chloride hexahydrate solution, with a dropping speed of 2 mL/min, and stir continuously until there is no more When bubbles appear, the reaction is complete. Leave it to settle for half an hour. Then filter it and dry it in a vacuum drying oven with a vacuum of 100 Pa and 120°C for 6 hours. Finally, the Co-B precursor is obtained.

2) Preparation of Ru-Co-B based oxide catalyst

According to the standard that the molar ratio of ruthenium element to cobalt element is 1:11, weigh 0.0724g anhydrous ruthenium trichloride; according to the standard that the mass ratio of Co-B precursor to anhydrous ruthenium trichloride is 1:1, Weigh 0.0724g Co-B precursor, mix the precursor with the weighed anhydrous ruthenium trichloride and grind it fully, then put the mixed solid particles into a low-temperature plasma device, in an air-state atmosphere, at a voltage of 50V , energized for 10 minutes, and finally the Ru-Co-B catalyst was obtained.

Characterize the Ru-Co-B-based oxide catalyst prepared in this example.

1. XRD spectrum

The XRD physical characterization results of the product prepared in this example are the same as those in Example 1.

2. Battery performance

The Ru-Co-B-based oxide prepared in this example was used as the anode catalyst of the borohydride fuel cell DBFC, and CeO ₂ /C was used as the cathode catalyst to assemble a borohydride fuel cell. It was measured that the maximum power density of the fuel cell reached 170.72 mW·cm ^-2 .

In summary, the Ru-Co-B-based oxide prepared in the present invention is used as an anode catalyst in a borohydride fuel cell DBFC, and the maximum power density of the fuel cell reaches 143.12mW·cm ^-2 ~ 206.35mW·cm ^-2 . It has good catalytic activity and better discharge performance.

The performance of the ruthenium cobalt boron-based oxide catalyst prepared in the present invention is further verified through the following experiments.

Verify 1

Under the same conditions, the ruthenium cobalt boron-based oxide nanocatalyst with heterogeneous structure prepared in Example 1 was compared with commercial Pt/C, commercial Pt-Ru/C, chemically prepared ruthenium cobalt boron catalyst and cobalt boron The power of the catalyst is compared, and the results are shown in Figure 7.

The operation method of the ruthenium cobalt boron catalyst prepared by chemical method is as follows: refer to the ratio of Example 1 to mix the three solutions of ruthenium salt solution, cobalt salt solution and boride solution in sequence at room temperature, and stir evenly to obtain the catalyst. .

It can be concluded from Figure 7 that the heterostructured ruthenium-cobalt-boron-based oxide nanocatalyst prepared using plasma technology has excellent electrochemical properties, its power is much higher than other catalysts, and the battery discharge performance has been improved. . Therefore, the method of the present invention has good application prospects.

Verification 2

The stability of the ruthenium cobalt boron-based oxide catalyst prepared in Example 1 was studied.

For the ruthenium-cobalt-boron-based oxide catalyst after repeated use for a week, under constant current discharge, the changing trend of battery voltage and discharge time was obtained. The results are shown in Figure 8.

Referring to Figure 8, it can be seen that after nearly a week of use, the ruthenium cobalt boron-based oxide catalyst can still have good discharge performance under constant current discharge for more than 80 hours, indicating that the catalyst prepared by this method has good stability and has Broad commercial application prospects.

The above are only a few sets of embodiments of the present invention, and do not limit the present invention in any way. Any simple modifications, changes and equivalent changes made to the above embodiments based on the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention. Inside.

Claims (10)

1. A method for preparing a heterostructure ruthenium-cobalt-boron-based oxide catalyst, which is characterized by comprising the following steps: 1) Preparation of Co-B precursor Weigh the cobalt salt and boron hydride respectively according to the molar ratio of cobalt element to boron element 1:2, and obtain the Co-B precursor through dissolution, stirring, precipitation, separation and drying; 2) Preparation of Ru-Co-B based oxide catalyst Weigh the ruthenium salt and Co-B precursor respectively according to the molar ratio of ruthenium element to cobalt element 1: (4-16), and obtain the Ru-Co-B-based oxide catalyst after mixing, grinding, and plasma technology treatment. 2. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 1, characterized in that in step 2), the conditions for plasma technology treatment are: voltage 40V-70V, treatment time 5min -20min, the temperature is normal temperature. 3. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 1, characterized in that in step 2), the ruthenium salt is anhydrous ruthenium trichloride, ruthenium nitrate, ruthenium sulfate or Ruthenium acetate. 4. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 1, characterized in that the step 1) specifically includes the following steps: 1.1) Dissolve the weighed cobalt salt in water to obtain a cobalt salt solution; 1.2) Dissolve the weighed borohydride in water to obtain a borohydride solution; 1.3) Add the borohydride solution dropwise to the cobalt salt solution, stir until the reaction is complete, leave to settle, filter, separate and dry to obtain the Co-B precursor. 5. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 4, characterized in that in the step 1.1), the concentration of the cobalt salt solution is 0.015 mol/L; the cobalt salt is hexahydrate Cobalt chloride, anhydrous cobalt chloride, cobalt chloride, cobalt sulfate, cobalt nitrate or cobalt carbonate. 6. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 4, characterized in that in the step 1.2), the borohydride is potassium borohydride, sodium borohydride or lithium borohydride, The concentration of potassium borohydride solution is 0.03mol/L. 7. The preparation method of the heterostructure ruthenium cobalt boron-based oxide catalyst according to claim 4, characterized in that in the step 1.3), the dropping speed is 1mL/min～2mL/min; the drying condition is: vacuum Degree 80Pa-100Pa, temperature 60℃~120℃, time 6h-12h. 8. A ruthenium cobalt boron based oxide catalyst prepared by the preparation method of a heterostructure ruthenium cobalt boron based oxide catalyst according to any one of claims 1 to 7, characterized in that, the ruthenium cobalt boron based oxide catalyst The oxide catalyst is a core-shell-lamellar mosaic heterostructure. 9. Application of the ruthenium cobalt boron-based oxide catalyst as claimed in claim 8 as an anode catalyst in a borohydride fuel cell. 10. The application according to claim 9, characterized in that the maximum power density of the borohydride fuel cell is 143.12mW·cm ^-2 ~ 206.35mW·cm ^-2 .