A diamond electrode and its preparation method

Abstract

The present application relates to the technical field of electrode preparation, and specifically to a diamond electrode and a preparation method thereof. The diamond electrode comprises a porous consolidated block formed by consolidating conductive diamond particles; the particle size of the conductive diamond particles is 0.3-10 mm; the conductive diamond particles include diamond particles or diamond particles with a diamond coating deposited on the surface; the diamond particles or the diamond coating are made conductive by doping elements. On the basis of the above, the present application also deposits a nano-diamond porous film on the surface of the porous consolidated block, and the thickness of the nano-diamond porous film is 1-20 μm. In addition, the present application also provides a preparation method for the above-mentioned diamond electrode. The diamond electrode provided in the present application has a high specific surface area and is capable of controlling the pores inside the electrode and exposing the pores to the working environment.

Description

Technical Field

[0001] The present application relates to the technical field of electrode preparation, and in particular to a diamond electrode and a preparation method thereof. Background Art

[0002] Diamond is a material with unique physical and chemical properties. It does not easily react with acids, bases, and salts, and has good chemical stability. In recent years, researchers have applied it to fields such as the electrochemical degradation of organic wastewater. Through boron doping, diamond can be transformed into a semiconductor or a conductor with metallic properties. Compared with traditional electrodes, boron-doped diamond electrodes have many advantages, such as a wide electrochemical window, good electrochemical stability, excellent mechanical properties, strong corrosion resistance, and good conductivity. In particular, for refractory organic pollutants that are difficult to remove using biochemical treatment methods, the use of boron-doped diamond electrodes can often completely mineralize the refractory organic pollutants, thereby achieving their removal.

[0003] However, existing boron-doped diamond electrodes are mostly planar electrodes with a low specific surface area. This results in defects such as a small active area, low spatial yield of hydroxyl radicals, a strong oxidizing group, and slow mass transfer rates. These defects also limit the electrocatalytic performance of existing boron-doped diamond electrodes. Furthermore, existing diamond electrodes have small internal pores, most of which are non-through pores, which are easily clogged by debris or reaction products. This results in these pores not being exposed to the working environment, making them difficult to adapt to different working environments and resulting in low operating efficiency.

[0004] Therefore, there is an urgent need for a diamond electrode with a high specific surface area, which can control the internal pores of the electrode and expose the pores to the working environment. Summary of the Invention

[0005] The present application provides a diamond electrode and a method for preparing the same. The diamond electrode has a high specific surface area and can control the internal pores of the electrode and expose the pores to the working environment.

[0006] In a first aspect, the present application provides a diamond electrode, which adopts the following technical solution:

[0007] A diamond electrode comprising a porous consolidated block formed by consolidating conductive diamond particles; the conductive diamond particles have a particle size of 0.3-10 mm;

[0008] The conductive diamond particles include diamond particles or diamond particles with a diamond coating deposited on the surface;

[0009] The diamond grains or the diamond coating are made conductive by doping elements.

[0010] The main structure of the diamond electrode provided by the present application is a porous consolidation block formed by consolidating diamond particles or diamond particles with diamond coatings deposited on the surface. The setting of the porous consolidation block makes the diamond electrode provided by the present application a three-dimensional electrode, which can increase the active specific surface area of ​​the diamond electrode itself. The diamond electrode of the present application has diamond particles with diamond coatings deposited on the surface or a consolidation layer deposited between the diamond particles, so that the diamond particles are consolidated together. The diamond particles in the consolidation block or the diamond particles with diamond coatings deposited on the surface have large through-pores. The pores are fully exposed to the working environment of the diamond electrode, making the diamond electrode provided by the present application a three-dimensional electrode, and the processed liquid can flow freely and transfer mass in the pores. The setting of the pores greatly increases the active specific surface area of ​​the diamond electrode, improves the working efficiency of the diamond electrode, and can also achieve the purpose of controlling the internal pores of the diamond electrode by changing the size of the above-mentioned diamond particles and the thickness of the coating.

[0011] Optionally, the diamond particles or the diamond particles with diamond coating deposited on the surface have a particle size of 1-5 mm.

[0012] In a specific embodiment, the diamond particles or the diamond particles with diamond coating deposited on the surface have a particle size of 0.3 mm, 1 mm, 3 mm, 5 mm, 8 mm, or 10 mm.

[0013] In some specific embodiments, the diamond particles or the diamond particles with diamond coating deposited on the surface have a particle size of 0.3-1 mm, 0.3-3 mm, 0.3-5 mm, 0.3-8 mm, 1-3 mm, 1-5 mm, 1-8 mm, 1-10 mm, 3-5 mm, 3-8 mm, 3-10 mm, 5-8 mm, 5-10 mm, or 8-10 mm.

[0014] Optionally, the thickness of the diamond coating is 1-20 μm, and the particle size of the diamond grains is 0.5-10 μm; the diamond particles with the diamond coating deposited on the surface form the porous consolidated block through a consolidation layer, the thickness of the consolidation layer is 2-20 μm, and the particle size of the diamond grains is 0.5-15 μm; the sum of the thickness of the diamond coating and the consolidation layer is ≥5 μm.

[0015] Optionally, the diamond coating has a thickness of 5-15 μm.

[0016] In a specific embodiment, the thickness of the diamond coating is 1 μm, 5 μm, 10 μm, 15 μm, or 20 μm.

[0017] In some specific embodiments, the thickness of the diamond coating is 1-5 μm, 1-10 μm, 1-15 μm, 5-10 μm, 5-15 μm, 5-20 μm, 10-15 μm, 10-20 μm, or 15-20 μm.

[0018] Optionally, the consolidation layer has a thickness of 5-15 μm.

[0019] In a specific embodiment, the thickness of the consolidation layer is 2 μm, 5 μm, 10 μm, 15 μm, or 20 μm.

[0020] In some specific embodiments, the thickness of the consolidation layer is 2-5 μm, 2-10 μm, 2-15 μm, 5-10 μm, 5-15 μm, 5-20 μm, 10-15 μm, 10-20 μm, or 15-20 μm.

[0021] The sum of the thicknesses of the diamond coating and the solidification layer is ≥5 μm.

[0022] In a specific embodiment, the sum of the thickness of the diamond coating and the consolidation layer is 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or 35 μm.

[0023] In some specific embodiments, the sum of the thicknesses of the diamond coating and the consolidation layer is 5-10 μm, 5-15 μm, 5-20 μm, 5-25 μm, 5-35 μm, 10-15 μm, 10-20 μm, 10-25 μm, 10-30 μm, 10-35 μm, 15-20 μm, 15-30 μm, 15-35 μm, 20-25 μm, 20-30 μm, 20-35 μm, 25-30 μm, 25-35 μm, or 30-35 μm.

[0024] Optionally, the diamond particles with diamond coating deposited on the surface contain substrate particles; the material of the substrate particles is selected from diamond, silicon carbide, silicon dioxide and silicon.

[0025] In a specific embodiment, the substrate particles may be made of diamond.

[0026] In a specific embodiment, the substrate particles may be made of silicon carbide.

[0027] In a specific embodiment, the material of the substrate particles may be silicon dioxide.

[0028] In a specific embodiment, the substrate particles may be made of silicon.

[0029] Optionally, a nano-diamond porous film is deposited on the surface of the porous consolidated block; the nano-diamond porous film is made conductive by doping elements.

[0030] Optionally, the thickness of the nanodiamond porous film is 1-20 μm, and the diameter of the diamond grains is 10-800 nm.

[0031] Optionally, the thickness of the nanodiamond porous membrane is 2-12 μm, and the diameter of the diamond grains is 35 nm-500 nm.

[0032] The outer surface of the diamond electrode of the present application is also provided with a nano-diamond porous membrane, which can form a porous structure on the electrode surface. The pore size in the nano-diamond porous membrane is nanoscale. Although it is a non-through pore, it is an open pore that connects the interior of the consolidated block with the outside world. The ions in the liquid can transfer mass and exchange charges in the pores by diffusion, further increasing the active specific surface area of ​​the diamond electrode.

[0033] The doping element in the present application can be any element in the periodic table that can make diamond conductive through doping.

[0034] Optionally, the doping element is selected from any one of B, P, S, Li and Ba.

[0035] In a specific embodiment, the doping element may be B.

[0036] In a specific embodiment, the doping element may be P.

[0037] In a specific embodiment, the doping element may be S.

[0038] In a specific embodiment, the doping element may be Li.

[0039] In a specific embodiment, the doping element may be Ba.

[0040] In a second aspect, the present application provides a method for preparing the above-mentioned diamond electrode, which adopts the following technical solution:

[0041] A method for preparing a diamond electrode specifically comprises the following steps: piling prepared conductive diamond particles and continuously depositing a consolidation layer on the surface, thereby consolidating the conductive diamond particles to prepare a porous consolidation block.

[0042] Furthermore, the method also includes the following steps: depositing a nano-diamond porous membrane on the surface of the porous consolidated block, specifically: etching the surface of the porous consolidated block to form etch pits; then using chemical vapor deposition and etching processes alternately to deposit and etch to prepare the nano-diamond porous membrane.

[0043] In a specific embodiment, a method for preparing a diamond electrode comprises the following steps:

[0044] (1) depositing a doped diamond coating on the surface of a substrate particle to obtain a diamond particle having a diamond coating deposited on the surface;

[0045] (2) piling up the diamond particles with diamond coating deposited on the surface obtained in step (1) and further depositing a diamond-doped consolidation layer on the surface, thereby consolidating the diamond particles with diamond coating deposited on the surface to obtain a porous consolidation block;

[0046] (3) depositing a nano-diamond porous membrane on the surface of the porous consolidated block obtained in step (2), specifically: etching the surface of the porous consolidated block to form etch pits; then depositing and etching by alternating chemical vapor deposition and etching processes to prepare the nano-diamond porous membrane.

[0047] When the present application uses diamond particles with diamond coatings deposited on the surface to prepare diamond electrodes, the deposition is performed using chemical vapor deposition.

[0048] When the present application uses diamond particles with a diamond coating deposited on the surface to prepare a diamond electrode, the diamond particles with a diamond coating deposited on the surface are first produced, and then a diamond-doped consolidation layer is deposited between the diamond particles with the diamond coating deposited on the surface. The diamond particles are consolidated into blocks using a two-step deposition method, and then a nano-diamond porous film is deposited on the surface of the consolidated block to complete the preparation of the electrode. The entire preparation process is simple and easy to operate.

[0049] In summary, this application includes at least one of the following beneficial technical effects:

[0050] 1. The main structure of the diamond electrode provided in the present application is a porous consolidated block formed by consolidating diamond particles or diamond particles with a diamond coating deposited on the surface. The setting of the porous consolidated block makes the diamond electrode provided in the present application a three-dimensional electrode, which can increase the specific surface area of ​​the diamond electrode itself.

[0051] 2. The diamond electrode of the present application has a consolidation layer deposited between the diamond particles or between the diamond particles, so that the diamond particles are consolidated together. The diamond particles or between the diamond particles in the consolidation block have large through-pores. The pores are fully exposed to the working environment of the diamond electrode, making the diamond electrode provided by the present application a three-dimensional electrode. The processed liquid can flow freely and transfer mass in the pores. The setting of such pores greatly increases the active specific surface area of ​​the diamond electrode and improves the working efficiency of the diamond electrode. The purpose of controlling the internal pores of the diamond electrode can also be achieved by changing the size of the above-mentioned diamond particles and the thickness of the coating to meet different application requirements.

[0052] 3. The outer surface of the diamond electrode of the present application is also provided with a nano-diamond porous membrane, which can form a porous structure on the electrode surface. The pore size in the nano-diamond porous membrane is nanoscale. Although it is a non-through pore, it is an open pore that connects the interior of the consolidated block with the outside world. The ions in the liquid can transfer mass and exchange charges in the pores by diffusion, further increasing the active specific surface area of ​​the diamond electrode.

[0053] 4. This application first produces diamond particles with a diamond coating deposited on the surface, and then deposits a diamond-doped consolidation layer between the diamond particles with the diamond coating deposited on the surface. The diamond particles are consolidated into blocks using a two-step deposition method, and then a nano-diamond porous film is deposited on the surface of the consolidated block to complete the preparation of the electrode. The entire preparation process is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is an example of diamond particles with a diamond coating deposited on the surface (the shape of the substrate particles is spherical particles).

[0055] Figure 2 This is Example 2 of diamond particles with diamond coating deposited on the surface (the shape of the substrate particles is a polyhedral particle).

[0056] Figure 3 It is a structural diagram of the consolidation tooling.

[0057] Figure 4 Schematic diagram of the structure of the porous consolidated block prepared in Example 1.

[0058] Figure 5 This is the SEM morphology of the surface of the porous consolidated block in Example 1.

[0059] Figure 6 This is the SEM morphology of the nanodiamond porous membrane in Example 17.

[0060] Explanation of the accompanying symbols: 1. Diamond particles; 11. Substrate particles; 12. Diamond coating; 2. Consolidation tooling; 21. Size limiting ring; 22. Limiting grid; 3. Porous consolidation block. DETAILED DESCRIPTION

[0061] Before describing the embodiments of the present application in detail, it should be understood that the terminology used herein is only for the purpose of describing particular embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the term belongs.

[0062] The present application provides a diamond electrode comprising a porous consolidated block formed by consolidating conductive diamond particles; the conductive diamond particles have a particle size of 0.3-10 mm; the conductive diamond particles include diamond particles or diamond particles with a diamond coating deposited on their surface; the diamond particles or diamond coating are made conductive by doping with elements. Preferably, the diamond particles or diamond particles with a diamond coating deposited on their surface have a particle size of 1-5 mm.

[0063] Furthermore, the diamond coating has a thickness of 1-20 μm, and the diamond grains have a particle size of 0.5-10 μm. The diamond particles with the diamond coating deposited on their surfaces are formed into a porous consolidated mass through a consolidation layer. The consolidation layer has a thickness of 2-20 μm, and the diamond grains have a particle size of 0.5-15 μm. The combined thickness of the diamond coating and the consolidation layer is ≥ 5 μm. The diamond particles with the diamond coating deposited on their surfaces contain substrate particles, and the substrate particles are made of a material selected from diamond, silicon carbide, silicon dioxide, and silicon.

[0064] On the basis of the above, a nano-diamond porous film is also deposited on the surface of the porous consolidated block; the nano-diamond porous film is made conductive by doping elements. The thickness of the nano-diamond porous film is 1-20μm, and the diameter of the diamond grains is 10-800nm.

[0065] In the present application, the doping element is selected from any one of B, P, S, Li and Ba.

[0066] The present application also provides a method for preparing a diamond electrode. The preparation method specifically comprises the following steps:

[0067] (1) depositing a doped diamond coating on the surface of a substrate particle to obtain a diamond particle having a diamond coating deposited on the surface;

[0068] (2) piling up the diamond particles with diamond coating deposited on the surface obtained in step (1) and further depositing a diamond-doped consolidation layer on the surface, thereby consolidating the diamond particles with diamond coating deposited on the surface to obtain a porous consolidation block;

[0069] (3) depositing a nano-diamond porous membrane on the surface of the porous consolidated block obtained in step (2), specifically: etching the surface of the porous consolidated block to form etch pits; then depositing and etching by alternating chemical vapor deposition and etching processes to prepare the nano-diamond porous membrane.

[0070] When the applicant was improving the electrode material, he found that most of the existing electrodes were in the form of boron-doped diamond, which turned the diamond into a semiconductor or a conductor with metallic properties, thereby obtaining a diamond electrode. However, most of the diamond electrodes in the related art adopt a planar design, and their specific surface area is low. The low specific surface area restricts the performance of the diamond electrodes in the related art. In addition, even if the existing diamond electrodes are three-dimensional electrodes, the interior of the diamond electrodes in the related art cannot be fully exposed to the working environment of the diamond electrode due to their own structural airtightness. In this case, the specific surface area of ​​the diamond electrode can only be increased by increasing the ratio between the outer surface of the diamond electrode and the size of the diamond electrode. However, the use of the above method to increase the specific surface area of ​​the diamond electrode is relatively limited, and it is impossible to prepare a diamond electrode with a high specific surface area.

[0071] Therefore, the applicant, starting from the internal pores of the diamond electrode, configured the diamond electrode into an electrode block composed of multiple conductive diamond particles. The conductive diamond particles are consolidated by a diamond-doped consolidation layer, forming large through-pores between the diamond particles. The pores are fully exposed to the working environment of the diamond electrode, allowing the processed liquid to flow freely and transfer mass in the pores. This makes the diamond electrode provided by this application a porous three-dimensional diamond electrode with an extremely high specific surface area.

[0072] The diamond electrode provided in this application can increase the specific surface area from two aspects:

[0073] Firstly, the diamond electrode provided by the present application is prepared by consolidating multiple conductive diamond particles, so that the diamond electrode provided by the present application forms a three-dimensional electrode, which can increase the specific surface area of ​​the diamond electrode itself;

[0074] Secondly, after consolidation, large through-pores are formed between the conductive diamond particles. The pores are fully exposed to the working environment of the diamond electrode. The treated liquid can flow and transfer mass freely in the pores, thereby further increasing the active specific surface area of ​​the diamond electrode.

[0075] In addition, a nano-diamond porous membrane is provided on the surface of the diamond electrode provided in the present application, and the interior of the consolidated block is connected to the outside world, so that ions in the liquid can transfer mass and exchange charges in the pores by diffusion, thereby further increasing the active specific surface area of ​​the diamond electrode provided in the present application.

[0076] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0077] The present application is further described in detail below with reference to the embodiments, drawings, comparative examples and performance test results.

[0078] The present application may adopt chemical vapor deposition, and the deposition parameters may be adjusted as needed. The selection of the deposition method and the adjustment of the deposition parameters will not have much impact on the preparation of the diamond electrode of the present application.

[0079] In this application, the shape of the substrate particles can be arbitrary. For example, Figure 1 As shown, the shape of the substrate particles 11 can be spherical particles; Figure 2 As shown, the shape of the substrate particles 11 can be polyhedral particles.

[0080] In the following examples, the doping element used is B. The boron source used is selected from diborane, borax, elemental boron, trimethyl boron, trimethyl borate, and the like.

[0081] In the following examples, Figure 2 Taking the middle substrate particles 11 as polyhedral particles as an example, the technical solution of the present application is explained.

[0082] Example 1

[0083] The present application provides a diamond electrode.

[0084] The method for preparing the diamond electrode specifically comprises the following steps:

[0085] (1) Preparation of diamond particles with diamond coating deposited on the surface

[0086] A. Pretreatment of substrate particles

[0087] The substrate particles were cleaned with anhydrous ethanol. The cleaned substrate particles were then ultrasonically treated with a diamond powder suspension for 30 minutes. Diamond seeds were then deposited on the surface of the substrate particles. The substrate particles were then cleaned with anhydrous ethanol and then deionized water, followed by drying. The diamond powder suspension contained 50% by mass of 5μm diamond powder and 50% by mass of 20μm diamond powder. Anhydrous ethanol was used as the solvent.

[0088] B. Figure 2 As shown, a diamond coating 12 is deposited on the surface of a substrate particle 11 pre-set with diamond seed crystals to produce a diamond particle 1 with a diamond coating deposited on the surface. The particle size of the diamond particle 1 with a diamond coating deposited on the surface, the material of the substrate particle 11, and the thickness of the diamond coating 12 are shown in Table 1.

[0089] The deposition process of diamond coating is as follows:

[0090] A CH4 / H2 / Ar deposition atmosphere was used, with a methane flow rate of 120 sccm, a hydrogen flow rate of 8 SLM, and an argon flow rate of 3 SLM; the deposition temperature was 830°C, the deposition pressure was 3 kPa; and the B / C ratio in the atmosphere was 5000 ppm.

[0091] (2) Consolidation of diamond particles

[0092] refer to Figure 3 This embodiment utilizes a specific consolidation tool 2. The consolidation tool 2 includes a size limiting ring 21, with two openings on each side of the size limiting ring 21 provided with a limiting grid 22. A consolidation cavity is formed between the limiting grid 22 and the size limiting ring 21. The consolidation cavity is used to accommodate the diamond particles 1 with a diamond coating deposited on their surfaces.

[0093] The diamond particles 1 with diamond coating deposited on the surface are filled into the consolidation cavity, and a diamond-doped consolidation layer is further deposited on the surface, thereby consolidating the diamond particles 1 with diamond coating deposited on the surface, removing the consolidation tool 2, and obtaining a porous consolidation block 3, as shown in FIG. Figure 4 shown.

[0094] The deposition process of the consolidation layer is as follows:

[0095] A CH4 / H2 / Ar deposition atmosphere was used, with a methane flow rate of 120 sccm, a hydrogen flow rate of 8 SLM, and an argon flow rate of 3 SLM; the deposition temperature was 830°C, the deposition pressure was 3 kPa; and the B / C ratio in the atmosphere was 5000 ppm.

[0096] In this embodiment, the SEM morphology of the porous consolidated block surface is as follows: Figure 5 As shown. Figure 5 It can be seen that the crystal form of diamond grains on the surface of diamond particles is complete.

[0097] Examples 2-6

[0098] Examples 2-6 each provide a diamond electrode. The difference between the above examples and Example 1 is that the diamond particles with diamond coating deposited on the surface have different particle sizes, as shown in Table 1. The remaining parameters and steps are consistent with Example 1.

[0099] Examples 7-13

[0100] Examples 7-13 each provide a diamond electrode. The above examples differ from Example 4 in that the coating thickness of the diamond particles is different, as shown in Table 1. The remaining parameters and steps are consistent with Example 4.

[0101] Examples 14-16

[0102] Examples 14-16 each provide a diamond electrode. The above examples differ from Example 4 in that the materials of the substrate particles are different, as shown in Table 1. The remaining parameters and steps are consistent with those of Example 4.

[0103] Table 1 Partial parameters of diamond electrodes provided in the examples and comparative examples

[0104]

[0105]

[0106] Example 17

[0107] Example 17 provides a diamond electrode. The difference between this example and Example 4 is that a nano-diamond porous film is deposited on the surface of the porous consolidated block.

[0108] The method for preparing the diamond electrode specifically comprises the following steps:

[0109] (1) Preparation of diamond particles with diamond coating deposited on the surface: same as in Example 1.

[0110] (2) Consolidation of diamond particles with diamond coating deposited on the surface: Same as Example 1.

[0111] (3) Deposition of nanodiamond porous film:

[0112] A nanodiamond porous membrane was deposited on the surface of the porous consolidated block prepared in step (2). Specifically, the surface of the porous consolidated block was etched to form pits; then, a diamond deposition and etching process were alternately performed using chemical vapor deposition (CVD) and etching to prepare the porous membrane. The CVD process lasted 10 minutes, followed by a single plasma etching step, with the etching time being one-third of the CVD time. The thickness of the porous membrane is shown in Table 1.

[0113] The etching process is as follows: hydrogen-argon plasma etching is performed using an H2 / Ar etching atmosphere.

[0114] The etching parameters are as follows: in H2 / Ar etching atmosphere, the hydrogen flow rate is 8 SLM, the argon flow rate is 3 SLM; the etching temperature is 950°C, and the etching pressure is 3.5 kPa.

[0115] The deposition process of nanodiamond porous film is as follows:

[0116] A CH4 / H2 / Ar deposition atmosphere was used, with the methane flow rate set to 480 sccm, the hydrogen flow rate to 8 slm, the argon flow rate to 3 slm, the deposition temperature to 780°C, and the deposition pressure to 3.0 kPa; the B / C ratio in the atmosphere was 5000 ppm; after 10 minutes of deposition, the introduction of methane and B was suspended to form an H2 / Ar etching atmosphere, and hydrogen-argon plasma etching was performed, with the etching time being 1 / 3 of the deposition time; after the etching was completed, methane was continued to be introduced into the H2 / Ar etching atmosphere and B was introduced, and deposition and etching were performed alternately to form a nanodiamond porous membrane.

[0117] In this embodiment, the SEM morphology of the chemical vapor deposition nanodiamond porous film on the surface of the porous consolidated block is as follows: Figure 6 As shown. Figure 6 It can be seen that the nanodiamond porous membrane has an obvious porous structure.

[0118] Examples 18-23

[0119] Examples 18-23 each provide a diamond electrode. The difference between the above examples and Example 17 is that the thickness of the nanodiamond porous membrane is different, as shown in Table 1. The remaining parameters and steps are consistent with Example 4.

[0120] Example 24

[0121] This embodiment provides a diamond electrode. The difference between the above embodiment and embodiment 4 is that diamond particles are consolidated into a porous consolidated block, as shown in Table 1. The remaining parameters and steps are consistent with embodiment 4.

[0122] Example 25

[0123] This embodiment provides a diamond electrode. The difference between the above embodiment and embodiment 19 is that the diamond particles are consolidated into a porous consolidated block, as shown in Table 1. The remaining parameters and steps are consistent with embodiment 4.

[0124] Comparative Example

[0125] Comparative Example 1-2

[0126] Comparative Examples 1 and 2 each provide a diamond electrode. The difference between the above embodiment and Example 4 is that the particle size of the diamond particles is different, as shown in Table 1. The remaining parameters and steps are consistent with Example 4.

[0127] Comparative Example 3

[0128] Comparative Example 3 provides a diamond electrode.

[0129] Taking into account production costs and time costs, this comparative example differs from Example 4 in that, in step (2), when depositing the consolidation layer, the deposition is stopped when the consolidation layer grows until the pores on the surface of the accumulated diamond particles are completely filled, thereby producing a consolidated block. The remaining parameters and steps are consistent with Example 4.

[0130] Performance test results

[0131] (1) Active specific surface area detection

[0132] The active specific surface areas of the diamond electrodes prepared in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0133] The detection method is as follows: the active specific surface area of ​​the diamond electrode is expressed as the effective active area per unit volume of the electrode, which is calculated using the chronocoulometry method. The test solution is 0.1M KCl / 0.1mM K3[Fe(CN)6].

[0134] (2) Aqueous solution potential window

[0135] The aqueous solution potential windows of the diamond electrodes prepared in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0136] The detection method is as follows: the current-cyclic voltammetry scanning method is used for measurement, the working electrode is a diamond electrode, the auxiliary electrode is a Pt electrode, the reference electrode is a saturated calomel electrode, the solution is 0.2M Na2SO4, and the cyclic scanning rate is 0.1V / s.

[0137] As shown in Table 1, the smaller the particle size of the conductive diamond particles, the larger the active specific surface area. However, when the particle size is too small, the pores between the particles are small, and the pores between some particles are blocked when the consolidation layer is deposited. Therefore, the active specific surface area of ​​the diamond electrode obtained is reduced. At the same time, when the particle size of the conductive diamond particles is the same, the thicker the consolidation layer, the smaller the active specific surface area. In addition, when the particle size of the conductive diamond particles is the same and different particle substrate materials are used, the active specific surface area will not undergo significant changes due to different substrate materials. Based on the above, the technical solution of the present application can effectively improve the active specific surface area of ​​the prepared diamond electrode.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A diamond electrode, characterized in that: The method comprises forming a porous consolidated block by using conductive diamond particles through a consolidated layer; the particle size of the conductive diamond particles is 1-5 mm; The conductive diamond particles include diamond particles or diamond particles with a diamond coating deposited on the surface; The diamond grains or the diamond coating are made conductive by doping elements; A nano-diamond porous film is also deposited on the surface of the porous consolidated block; the nano-diamond porous film is made conductive by doping elements; and the thickness of the nano-diamond porous film is 2-12 μm.

2. The diamond electrode according to claim 1, characterized in that The thickness of the diamond coating is 1-20 μm, and the particle size of the diamond grains is 0.5-10 μm.

3. The diamond electrode according to claim 1, characterized in that The thickness of the consolidation layer is 2-20 μm, and the particle size of the diamond grains is 0.5-15 μm.

4. The diamond electrode according to claim 1, characterized in that The sum of the thicknesses of the diamond coating and the solidification layer is ≥5 μm.

5. The diamond electrode according to claim 1, characterized in that The thickness of the diamond coating is 5-15 μm.

6. The diamond electrode according to claim 1, characterized in that The thickness of the consolidation layer is 5-15 μm.

7. The diamond electrode according to claim 1, characterized in that The diamond particles with diamond coating deposited on the surface contain substrate particles; the material of the substrate particles is selected from diamond, silicon carbide, silicon dioxide and silicon.

8. The diamond electrode according to claim 1, characterized in that The particle size of the diamond grains in the nano-diamond porous membrane is 10-800 nm.

9. The diamond electrode according to claim 1, characterized in that The particle size of the diamond grains in the nano-diamond porous membrane is 35nm-500nm.

10. The diamond electrode according to claim 1, characterized in that The doping element is selected from any one of B, P, S, Li and Ba.

11. A method for preparing a diamond electrode according to any one of claims 1 to 10, characterized in that: The following steps are involved: The prepared conductive diamond particles are piled up, and a consolidation layer is further deposited on the surface, thereby consolidating the conductive diamond particles to obtain a porous consolidated block.

12. The method for preparing a diamond electrode according to claim 11, wherein: The following steps are also included: The nano-diamond porous membrane is deposited on the surface of the porous consolidated block, specifically: etching the surface of the porous consolidated block to form etch pits; then depositing and etching in an alternating manner of chemical vapor deposition and etching to prepare the nano-diamond porous membrane.

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