WO2020118510A1

WO2020118510A1 - Boron-silicon co-doped diamond electrode, preparation method therefor and use thereof

Info

Publication number: WO2020118510A1
Application number: PCT/CN2018/120236
Authority: WO
Inventors: 唐永炳; 胡渊; 杨扬; 徐梦琦; 张文军
Original assignee: 深圳先进技术研究院
Priority date: 2018-12-11
Filing date: 2018-12-11
Publication date: 2020-06-18

Abstract

A boron-silicon co-doped diamond electrode, a preparation method therefor and use thereof. The boron-silicon co-doped diamond electrode comprises a substrate and a boron-silicon co-doped diamond layer provided on the substrate. The boron-silicon co-doped diamond electrode can effectively improve the conductivity of a diamond layer by doping boron element into the diamond layer, and can effectively improve the catalytic activity of the diamond layer by doping silicon element. Therefore, boron-silicon co-doping significantly increases the conductivity and catalytic activity of the diamond electrode, and in turn improves the production of ammonia gas through electrocatalytic nitrogen reduction. A preparation method for a boron-silicon co-doped diamond electrode can prepare a boron-silicon co-doped diamond electrode having excellent catalytic performance by means of simple processes, thereby simplifying preparation steps and reducing costs. Also disclosed are application examples where the boron-silicon co-doped diamond electrode is applied to electrocatalytic nitrogen reduction.

Description

Boron silicon co-doped diamond electrode and preparation method and application thereof

Technical field

The invention belongs to the technical field of electrochemical catalysis, and in particular relates to a borosilicate co-doped diamond electrode and a preparation method and application thereof.

Background technique

Ammonia has a very important role in human society. It can not only be used in chemical production, but also promote the growth of crops. The use of electro-catalytic nitrogen reduction to generate ammonia (Nitrogen Reduction) (NRR) technology is a potential solution to the problems faced in current industrial production. Whether the electrocatalytic reduction can be performed efficiently has high requirements on the catalytic activity of the electrode. At the same time, in aqueous solutions, the hydrogen evolution reaction is easier to perform than the NRR reaction, and the NRR reaction is often accompanied by side reactions. The above reasons restrict the conversion rate of ammonia.

At present, transition metals or transition metal compounds (such as transition metal oxides, transition metal nitrides, and transition metal carbides) are generally used as electrodes, but the above electrode materials still have many disadvantages, such as low catalytic activity and poor stability of electrode materials 1. By-products are produced during the reaction and the cost is high. Therefore, there is no efficient and safe electrode that can be used to catalyze the reduction of nitrogen to form ammonia.

Summary of the invention

In view of this, the present invention provides a boron-silicon co-doped diamond electrode and its preparation method and application. By doping silicon element and nitrogen element in the diamond layer, the conductivity and catalytic activity of the electrode are improved.

A first aspect of the present invention provides a borosilicate co-doped diamond electrode, which includes a substrate and a borosilicate co-doped diamond layer provided on the substrate.

A borosilicate co-doped diamond electrode provided in the first aspect of the present invention can effectively improve the conductivity of the diamond layer by doping boron element in the diamond layer; and the doping of silicon element can effectively improve the diamond layer Of catalytic activity. Therefore, the co-doping of borosilicate can effectively improve the conductivity and catalytic activity of diamond, and greatly increase the yield of electrocatalytic reduction of nitrogen to ammonia.

Wherein, the mass fraction of boron element in the borosilicate co-doped diamond layer is 0.05-0.5%, and the mass fraction of silicon element is 0.05-2.5%.

Wherein, the content of silicon element in the borosilicate co-doped diamond layer gradually increases from the side close to the base to the side far from the base.

Wherein, the grain size in the borosilicate co-doped diamond layer is 5-50 nm.

Wherein, the thickness of the borosilicate co-doped diamond layer is 500 nm-10 μm.

Wherein, the substrate is carbon cloth.

A second aspect of the present invention provides a method for preparing a borosilicate co-doped diamond electrode, including:

Take the base body, clean the base body, and then perform diamond seeding operation on the cleaned base body.

Depositing a boron-silicon co-doped diamond layer on the surface of the substrate to obtain a boro-silicon co-doped diamond electrode, the boro-silicon co-doped diamond electrode includes the substrate and the boro-silicon co-doped on the substrate Miscellaneous diamond layer.

The preparation method provided in the second aspect of the present invention can prepare a boron-silicon co-doped diamond electrode with excellent electrocatalytic nitrogen reduction to generate ammonia gas through a simple process. The preparation is simple, the cost is low, and the service life is under severe conditions Higher, with strong practicality.

Wherein, a hot-wire chemical vapor deposition method is used to deposit a boron-silicon co-doped diamond layer on the surface of the substrate. During the deposition process, the gases introduced include gaseous carbon source, hydrogen, argon, gaseous boron source and gaseous silicon Source, the flow rate of the gaseous carbon source is 7.5-25 sccm, the flow rate of the hydrogen gas is 25-132.5 sccm, the flow rate of the argon gas is 200-360 sccm, and the flow rate of the gaseous boron source is 10-100 sccm, The flow rate of the gaseous silicon source is 1-100 sccm, the deposition pressure is 1000-5000 Pa, the temperature of the substrate is 500-850° C., and the deposition time is 1-10 h.

Wherein, the flow rate of the gaseous silicon source gradually increases.

The third aspect of the present invention provides the application of the borosilicate co-doped diamond electrode according to the first aspect of the present invention in electrocatalytic reduction of nitrogen.

In the third aspect of the present invention, the boron-silicon co-doped diamond electrode provided in the first aspect of the present invention is used to electrocatalyze the reduction of nitrogen to produce ammonia gas, and the catalytic efficiency and catalytic yield are high.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions in the embodiments of the present invention, the drawings to be used in the embodiments of the present invention will be described below.

1 is a schematic structural view of a borosilicate co-doped diamond electrode in an embodiment of the present invention;

2 is a schematic structural view of a borosilicate co-doped diamond electrode in another embodiment of the present invention;

FIG. 3 is a process flow diagram of a method for preparing a borosilicate co-doped diamond electrode in an embodiment of the present invention.

detailed description

The following are the preferred embodiments of the present invention. It should be noted that those of ordinary skill in the art can make several improvements and retouching without departing from the principles of the present invention. These improvements and retouching are also considered as The scope of protection of the invention.

Please refer to FIG. 1, a boron-silicon co-doped diamond electrode provided by an embodiment of the present invention includes a substrate 1 and a boron-silicon co-doped diamond layer 2 disposed on the substrate 1.

First of all, the diamond layer has a certain chemical inertness, so it can effectively improve the stability and service life of the borosilicate co-doped diamond electrode. However, the diamond layer is a wide band gap semiconductor material, and its own conductivity is low. However, when boron is doped into the diamond layer, the conductivity of the electrode can be effectively improved, and even the conductivity of semi-metals or even metals can be achieved, and the resistivity can be as low as 0.001 Ω·cm. In addition, the boron-doped diamond electrode has the advantages of wide electrochemical window, low background current, etc. The wide electrochemical window and high hydrogen evolution potential can effectively inhibit the hydrogen evolution reaction, promote the NRR reaction, and improve the conversion of ammonia. rate.

Secondly, because nitrogen has a weak Lewis basicity, it is necessary to find a Lewis acidic electrode catalyst to promote the adsorption and reaction of nitrogen molecules. The electronegativity (1.90) of silicon element 21 is lower than that of boron (2.04) and C (2.55). When silicon element 21 is doped in the diamond layer or the boron-doped diamond layer, the positively charged silicon atoms It is more conducive to the adsorption of nitrogen, thereby providing excellent catalytic active sites for the generation of ammonia, making the electrode have excellent selective reduction during the catalytic reaction, can effectively prevent the generation of by-products, and improve the silicon-doped diamond electrode Of catalytic activity. Therefore, when the boron element and the silicon element 21 are doped into the diamond layer at the same time, the conductivity and catalytic activity of the boron-silicon co-doped diamond electrode can be simultaneously improved, and the conversion rate of ammonia gas is greatly improved. In addition, through the co-doping of boron and silicon element 21, the thermal expansion coefficient between the substrate 1 and the diamond film is adjusted, so that the thermal expansion coefficients between the two are closer, thereby improving the bonding performance between the diamond film and the substrate 1, To a certain extent, the stability of the electrode is improved. At the same time, the boron-silicon co-doped diamond electrode without metal elements also reduces environmental pollution to a certain extent.

In a preferred embodiment of the present invention, the mass fraction of boron element in the borosilicate co-doped diamond layer 2 is 0.05-0.5%, the mass fraction of silicon element 21 is 0.05-2.5%, and the remaining mass fraction is carbon element.

Boron can increase the conductivity of the borosilicate co-doped diamond electrode, but at the same time it will narrow the electrochemical window and promote the hydrogen evolution reaction to a certain extent, thereby inhibiting the NRR reaction. When the content of boron element is too small, the conductivity of the borosilicate co-doped diamond electrode is poor, and when the content of boron element is too large, the hydrogen evolution reaction will be significantly promoted. Therefore, the present invention needs to incorporate appropriate boron element to obtain a boron-silicon co-doped diamond electrode with excellent comprehensive performance.

Similarly, silicon element 21 can improve the catalytic activity of borosilicate co-doped diamond electrodes, but silicon element 21 will generate silicon carbide in the diamond layer. Although both silicon and silicon carbide have good catalytic activity, silicon carbide is not conductive. Therefore, when the silicon element 21 is too little, the catalytic activity of the boron-silicon co-doped diamond electrode is poor, and when the silicon element 21 is too much, the conductivity of the boron-silicon co-doped diamond electrode decreases. Therefore, the present invention needs to dope with appropriate silicon element 21 to obtain a borosilicate co-doped diamond electrode with excellent comprehensive performance.

It can be seen from the above that the silicon element 21 and the boron element will affect each other. The silicon element 21 will generate silicon carbide to affect the conductivity of the boron-silicon co-doped diamond electrode, and the addition of the boron element can improve the conductivity. Therefore, the doping amounts of the silicon element 21 and the boron element are not simply doped separately. The silicon element 21 and the boron element are a whole and cannot be viewed independently. Therefore, the boron-silicon co-doped diamond electrode with excellent comprehensive performance can be obtained only if the boron-doped element has a mass fraction of 0.05-0.5% and the silicon element 21 has a mass fraction of 0.05-2.5%. Preferably, the mass fraction of boron element in the borosilicate co-doped diamond layer 2 is 0.1-0.4%, and the mass fraction of silicon element 21 is 0.1-2%. More preferably, the mass fraction of boron element in the borosilicate co-doped diamond layer 2 is 0.2-0.3%, and the mass fraction of silicon element 21 is 0.15-2%.

In a preferred embodiment of the present invention, the silicon element, boron element and carbon element in the borosilicate co-doped diamond layer 2 may be evenly distributed, so that the comprehensive performance of the borosilicate co-doped diamond electrode reaches an average level to achieve a higher Service life. In addition, the silicon element, the boron element, and the carbon element may also be changed to achieve different performances in different parts of the boron-silicon co-doped diamond layer 2 to achieve higher catalytic performance. For example, by changing the element distribution on the side of the borosilicate co-doped diamond layer 2 close to the substrate 1, the bonding performance of the borosilicate co-doped diamond layer 2 and the substrate 1 is improved, or the borosilicate co-doped diamond layer 2 is far from the substrate 1 By changing the element distribution to improve the catalytic performance of the borosilicate co-doped diamond layer 2.

Referring to FIG. 2, in a preferred embodiment of the present invention, the content of silicon element 21 in the borosilicate co-doped diamond layer 2 gradually increases from the side close to the base 1 to the side far from the base 1. The silicon elements 21 in the boron-silicon co-doped diamond layer 2 of the present invention are not evenly distributed, because the silicon elements 21 can improve the catalytic activity, and during the use of the electrode, the most applied part is the surface of the electrode, so the silicon element 21 The gradual increase in the content from the side close to the base 1 to the side far from the base 1 can increase the content of silicon element 21 on the surface of the borosilicate co-doped diamond layer 2, further improving the borosilicate co-doped diamond electrode Of catalytic activity. Preferably, the content of the silicon element 21 is increased from 0.05% to 2.5%.

In a preferred embodiment of the present invention, the borosilicate co-doped diamond electrode further includes an electrode active material layer disposed on the surface of the borosilicate co-doped diamond layer 2. In the present invention, the boron-silicon co-doped diamond layer 2 containing the substrate 1 can serve as a current collector, and an active material layer is coated on the surface of the boron-silicon co-doped diamond layer 2 to form an electrode together.

In a preferred embodiment of the present invention, the borosilicate co-doped diamond layer 2 is provided on one side surface of the base 1 or the opposite sides of the base 1. Preferably, the borosilicate co-doped diamond layer 2 of the present invention may be provided on opposite sides of the substrate 1 to further improve the catalytic performance of the borosilicate co-doped diamond electrode.

In a preferred embodiment of the present invention, the grain size in the borosilicate co-doped diamond layer 2 is 5-50 nm. The grain size in the borosilicate co-doped diamond layer 2 is also an important factor that affects the ammonia conversion rate. The nano-scale grain size borosilicate co-doped diamond layer 2 has abundant grain boundaries and tunable defects. It can provide more catalytically active sites and thus has higher catalytic activity. Preferably, the grain size in the borosilicate co-doped diamond layer 2 is 10-40 nm. More preferably, the grain size in the borosilicate co-doped diamond layer 2 is 20-30 nm.

In a preferred embodiment of the present invention, the thickness of the borosilicate co-doped diamond layer 2 is 500 nm-10 μm. Preferably, the thickness of the borosilicate co-doped diamond layer 2 is 1 μm-8 μm. More preferably, the thickness of the borosilicate co-doped diamond layer 2 is 3 μm-6 μm.

In a preferred embodiment of the present invention, the substrate 1 is a carbon cloth. Carbon cloth has excellent electrical conductivity and electrochemical stability. At the same time, the carbon cloth usually has a three-dimensional network structure, which has a larger specific surface area than the existing silicon substrate 1 and can deposit diamond better; the boron-silicon co-doped high diamond layer is deposited on the three-dimensional network On the carbon cloth, therefore, the specific surface area of the borosilicate co-doped high diamond layer is also increased, and the active site of the borosilicate co-doped high diamond layer is further increased, which to a certain extent enhances the borosilicate co-doped high diamond layer The catalytic properties of diamond electrodes. Preferably, the carbon cloth is a three-dimensional network carbon cloth. Preferably, the mesh number of the carbon cloth is 50-200 mesh. More preferably, the mesh number of the carbon cloth is 100-150 mesh.

Referring to FIG. 3, a method for preparing a borosilicate co-doped diamond electrode provided by an embodiment of the present invention includes:

Step 1: Take the base body 1, clean the base body 1, and then perform a diamond seeding operation on the cleaned base body 1.

Step 2: Deposit a borosilicate co-doped diamond layer 2 on the surface of the substrate 1 to obtain a borosilicate co-doped diamond electrode. The borosilicate co-doped diamond electrode includes the substrate 1 and is disposed on the substrate 1 The borosilicate co-doped diamond layer 2.

The preparation method provided by the embodiment of the present invention can prepare a boron-silicon co-doped diamond electrode with excellent electrocatalytic nitrogen reduction to generate ammonia gas through a simple process. The preparation is simple, the cost is low, and the service life is more severe under severe conditions High, with strong practicality.

In a preferred embodiment of the present invention, a hot-wire chemical vapor deposition method is used to deposit a boron-silicon co-doped diamond layer 2 on the surface of the substrate 1. During the deposition process, the gases introduced include a gaseous carbon source, hydrogen, and argon , A gaseous boron source and a gaseous silicon source, the flow rate of the gaseous carbon source is 7.5-25sccm, the flow rate of the hydrogen gas is 25-132.5sccm, the flow rate of the argon gas is 200-360sccm, the flow rate of the gaseous boron source It is 10-100 sccm, the flow rate of the gaseous silicon source is 1-100 sccm, the deposition pressure is 1000-5000 Pa, the temperature of the substrate 1 is 500-850° C., and the deposition time is 1-10 h. Preferably, the gaseous carbon source is methane, the gaseous boron source is trimethylborane, and the gaseous silicon source is tetramethylsilane. Among them, trimethylborane is a mixed gas of trimethylborane and hydrogen, the concentration of trimethylborane in the mixed gas is 0.1%, and tetramethylsilane is a mixed gas of tetramethylsilane and hydrogen. Methylsilane concentration is 1%

In a preferred embodiment of the present invention, the flow rate of the gaseous silicon source gradually increases. Preferably, the flow rate of the gaseous silicon source is gradually increased from 0 to 100 sccm.

In a preferred embodiment of the present invention, in the deposition process, tantalum wire is used as the hot wire power source, the distance between the hot wire and the substrate 1 is 6-25 mm, the temperature of the hot wire is 2000-2400°C, and the power is 5000-7000w.

The application of the borosilicate co-doped diamond electrode according to the embodiment of the present invention provided in the embodiment of the present invention is used in electrocatalytic reduction of nitrogen.

The embodiments of the present invention utilize the boron-silicon co-doped diamond electrode provided by the embodiments of the present invention to electrically catalyze the reduction of nitrogen to produce ammonia gas, which has higher catalytic efficiency and catalytic yield. In addition, the borosilicate co-doped diamond electrode provided by the embodiment of the present invention can also be used to electrocatalyze carbon dioxide reduction, oxygen reduction, methanol oxidation and other electrochemical reactions, and also has high catalytic activity.

An embodiment of the present invention provides a dual-cell reactor for electrocatalytic reduction of nitrogen to form ammonia, which is characterized by comprising a working electrode, a counter electrode, and a reference electrode. The working electrode includes the one provided by the embodiment of the present invention. Boron silicon co-doped diamond electrode.

In the following, the present invention will be divided into multiple embodiments to further illustrate the embodiments of the present invention.

Example 1:

Step 1: Place the carbon in the beaker, add 50mL of acetone, place the beaker in the ultrasonic bath and clean it ultrasonically for 10min, then replace the acetone with ethanol, repeat the above process, and remove the impurities on the surface of the carbon cloth through two ultrasonic steps. Certain defects are formed on the surface to form planting sites. Then take out the carbon and arrange it in deionized water for ultrasonic cleaning for 10 min. Finally, the cleaned carbon was placed in a nano-diamond powder suspension and sonicated for 1 h. Diamond seeds were implanted on the surface of the carbon cloth. After the ultrasound was completed, the carbon cloth was dried at room temperature in a nitrogen stream.

Step 2: Use hot-wire chemical vapor deposition to deposit a boron-silicon co-doped diamond layer 2 on the surface of the carbon cloth, place the pre-treated carbon cloth substrate 1 on the base table in the chemical vapor deposition equipment, and keep the carbon cloth on The hot wire is in the middle and parallel to the hot wire, the distance between the hot wire and the surface of the carbon cloth is 20mm, and the power of the hot wire is 6900w. Pump the pressure in the furnace to less than 0.1Pa, then pass the reaction mixture gas, the gas flow includes gaseous methane, hydrogen, argon, trimethylborane and tetramethylsilane, the flow rate of methane is 10sccm, the flow rate of hydrogen 100sccm, the flow rate of argon is 360sccm, the flow rate of trimethylborane is 20sccm, the flow rate of tetramethylsilane is 10sccm, the deposition pressure is 1500Pa, the temperature of the substrate 1 is 500℃, the deposition time is 10h, and boron silicon is obtained Co-doped diamond electrode.

Example 2:

Step 2: Use hot-wire chemical vapor deposition to deposit a boron-silicon co-doped diamond layer 2 on the surface of the carbon cloth, place the pre-treated carbon cloth substrate 1 on the base table in the chemical vapor deposition equipment, and keep the carbon cloth on The hot wire is in the middle and parallel to the hot wire, the distance between the hot wire and the surface of the carbon cloth is 6mm, and the power of the hot wire is 5000w. Pump the pressure in the furnace to less than 0.1Pa, then pass the reaction mixture gas, the gas flow includes gaseous methane, hydrogen, argon, trimethylborane and tetramethylsilane, the flow rate of methane is 25sccm, the flow rate of hydrogen 25sccm, argon flow rate 200sccm, trimethylborane flow rate 100sccm, tetramethylsilane flow rate 100sccm, deposition pressure 5000Pa, substrate 1 temperature 850℃, deposition time 1h Co-doped diamond electrode.

Example 3:

Step 2: Hot wire chemical vapor deposition is used to deposit the borosilicate co-doped diamond layer 2 on the surface of the carbon cloth, and the pre-treated carbon cloth substrate 1 is placed on the base table in the chemical vapor deposition equipment to keep the carbon cloth The hot wire is in the middle and parallel to the hot wire, the distance between the hot wire and the surface of the carbon cloth is 15mm, and the power of the hot wire is 6000w. Pump the pressure in the furnace to less than 0.1Pa, and then pass the reaction mixture gas, the gas flow includes gaseous methane, hydrogen, argon, trimethylborane and tetramethylsilane, the flow rate of methane is 16sccm, the flow rate of hydrogen 132sccm, argon flow rate is 280sccm, trimethylborane flow rate is 60sccm, tetramethylsilane flow rate is 50sccm, deposition pressure is 3000Pa, substrate 1 temperature is 700℃, deposition time is 5h, borosilicate is obtained Co-doped diamond electrode.

Example 4: On the basis of Example 1, other experimental conditions remain unchanged, only the flow rate of argon gas is changed to 330 sccm, and the flow rate of tetramethylsilane is changed to 40 sccm.

Example 5: On the basis of Example 1, other experimental conditions remain unchanged, only the flow rate of argon gas is changed to 290 sccm, and the flow rate of tetramethylsilane is changed to 80 sccm.

Example 6: On the basis of Example 4, the other experimental conditions remain unchanged, the flow rate of hydrogen gas is changed to 330 sccm, and the flow rate of argon gas is changed to 100 sccm.

Example 7: On the basis of Example 4, other experimental conditions remain unchanged, the flow rate of tetramethylsilane is gradually increased from 1 to 40 sccm, and the flow rate of argon gas is gradually decreased from 360 to 330 sccm.

Effect example

The borosilicate co-doped diamond electrode obtained in Examples 1-7 was used to prepare a dual-cell reactor. A three-cell system is adopted, the prepared borosilicate co-doped diamond electrode is used as the working electrode, the graphite rod is the counter electrode, and the Ag/AgCl is the reference electrode, the working electrode and the counter electrode are separated by 2cm, and the reference electrode is close to the working electrode. A saturated 0.1M H2SO4 solution was added to the cathode chamber, and an equal volume of 0.1M H2SO4 solution was added to the anode chamber. The electrocatalytic reduction of N2 was carried out at a constant voltage of -1.05-0V, and then the reduction performance was tested in neutral and alkaline electrolytes. Finally, the production of ammonia gas by nitrogen reduction was determined by the indophenol blue method. The test results are shown in Table 1.

Table 1 Ammonia production

It can be seen from Table 1 that in Examples 1-7, the borosilicate co-doped diamond electrode obtained in Example 5 has the best performance of electrocatalytic nitrogen reduction to generate ammonia gas, has extremely high ammonia gas conversion rate, and has a strong Practicality. It can be seen from Example 1, Example 4 and Examples that as the flow rate of tetramethylsilane gradually increases from 10 sccm to 80 sccm, the catalytic performance of the borosilicate co-doped diamond electrode also gradually improves. It can be seen from Examples 4 and 6 that increasing the flow rate of hydrogen gas and reducing the flow rate of argon gas can adjust the grain size of diamond and the ratio of amorphous phase and sp ² phase in the diamond film, thereby increasing the borosilicate Catalytic performance of co-doped diamond electrodes. It can be seen from Example 4 and Example 7 that the content of silicon element 21 gradually increases from the side close to the base 1 to the side far from the base 1 so that boron-silicon co-doped silicon on the diamond surface Element 21 is greatly increased, further improving the catalytic performance of the borosilicate co-doped diamond electrode.

The above provides a detailed introduction to the content provided by the embodiments of the present invention. This article describes and explains the principles and embodiments of the present invention. The above description is only used to help understand the method of the present invention and its core ideas; at the same time, for the field of According to the idea of the present invention, general technical personnel will have changes in the specific implementation and application scope. In summary, the content of this specification should not be construed as limiting the present invention.

Claims

A boron-silicon co-doped diamond electrode, which includes a substrate and a boron-silicon co-doped diamond layer provided on the substrate.
The borosilicate co-doped diamond electrode according to claim 1, wherein the mass fraction of boron element in the borosilicate co-doped diamond layer is 0.05-0.5%, and the mass fraction of silicon element is 0.05-2.5%.
The boron-silicon co-doped diamond electrode according to claim 1, wherein the content of silicon element in the boron-silicon co-doped diamond layer gradually increases from a side close to the base to a side far from the base.
The borosilicate co-doped diamond electrode according to claim 1, wherein the grain size in the borosilicate co-doped diamond layer is 5-50 nm.
The borosilicate co-doped diamond electrode according to claim 1, wherein the thickness of the borosilicate co-doped diamond layer is 500 nm-10 μm.
The borosilicate co-doped diamond electrode according to claim 1, wherein the substrate is carbon cloth.
A preparation method of borosilicate co-doped diamond electrode, which includes:

Take the base body, clean the base body, and then perform diamond seeding operation on the cleaned base body;

Depositing a boron-silicon co-doped diamond layer on the surface of the substrate to obtain a boro-silicon co-doped diamond electrode, the boro-silicon co-doped diamond electrode includes the substrate and the boro-silicon co-doped on the substrate Miscellaneous diamond layer.
The preparation method according to claim 7, wherein a boron-silicon co-doped diamond layer is deposited on the surface of the substrate by hot-wire chemical vapor deposition, and the gas introduced during the deposition process includes a gaseous carbon source and hydrogen , Argon, gaseous boron source, and gaseous silicon source, the flow rate of the gaseous carbon source is 7.5-25sccm, the flow rate of the hydrogen gas is 25-132.5sccm, the flow rate of the argon gas is 200-360sccm, the gaseous state The flow rate of the boron source is 10-100 sccm, the flow rate of the gaseous silicon source is 1-100 sccm, the deposition pressure is 1000-5000 Pa, the temperature of the substrate is 500-850° C., and the deposition time is 1-10 h.
The preparation method according to claim 8, wherein the flow rate of the gaseous silicon source gradually increases.
The use of the borosilicate co-doped diamond electrode according to any one of claims 1-6 in electrocatalytic reduction of nitrogen.