Preparation method of pure nano diamond film
The preparation of pure nanodiamond films through surface high-temperature purification and oxygen-containing functional group grafting in solvent-heat reaction is solved, and the problem of high temperature and high cost in the existing technology is achieved, and the preparation of high-efficiency and simplified nanodiamond films is achieved. Wide application potential.
Patent Information
- Application Number
- CN202411326535.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2025-01-17
AI Technical Summary
In the prior art, the preparation method of nanodiamond film requires a high temperature and complex gas environment, the equipment cost is high, and it is difficult to achieve large-scale application, and it is difficult to obtain a pure diamond film in traditional methods.
The nanodiamond was subjected to high-temperature purification of the surface, and the addition of potassium persulfate and phosphorus pentoxide to concentrated sulfuric acid for oxygen-containing functional groups to graft to form negatively charged nanodiamonds, and then undergo solvothermal reaction in the solvent to obtain pure nanometers Diamond film.
It reduces the manufacturing cost of nanodiamond films, simplifies the process flow, and realizes the preparation of a uniform and controllable pure nanodiamond film, with huge application potential in the fields of electronics, optical and biomedical.
Smart Images
Figure CN119320132A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of superhard materials, and in particular relates to a method for preparing a pure nano diamond film. Background Art
[0002] As an emerging functional material, nanodiamond film has shown great application potential in many fields such as electronics, optics, and biomedicine in recent years. Its excellent physical and chemical properties, such as high hardness, high thermal conductivity, chemical inertness, and biocompatibility, make it a research hotspot. However, the preparation of pure nanodiamond film has always been one of the challenges faced by researchers. Traditional methods for preparing nanodiamond films mainly include chemical vapor deposition (CVD), laser ablation, and mechanical alloying. Among them, CVD is the most commonly used technology, which can produce large-size, high-purity diamond films. However, the CVD process often requires high temperature and a complex gas environment, and the equipment cost is high, making it difficult to achieve large-scale application. Other methods for synthesizing superhard materials, such as high temperature and high pressure method and explosion method, require relatively harsh reaction conditions. The sol-gel method can be used to prepare superhard abrasives such as diamond, but the prepared material contains ceramic binders, making it difficult to obtain pure diamond films. Summary of the invention
[0003] In order to reduce the manufacturing cost of nano-diamond film and simplify the process, the present invention mainly provides a method for preparing pure nano-diamond film.
[0004] In a first aspect, the present invention provides a method for preparing a pure nano-diamond film, comprising the following steps:
[0005] Step 1, placing the nanodiamond in a tube furnace, heating it to 800-1200° C. and keeping it at that temperature for 5-10 hours to perform high-temperature surface purification treatment;
[0006] Step 2, adding the nano-diamond, potassium persulfate and phosphorus pentoxide purified in step 1 into concentrated sulfuric acid respectively, stirring and reacting for 8 to 10 hours, filtering, washing the product with deionized water until it is neutral, and drying to obtain negatively charged nano-diamond with a large number of oxygen-containing functional groups grafted on the surface;
[0007] Step 3, uniformly dispersing the negatively charged nanodiamonds in a solvent, subjecting the formed suspension to a solvothermal reaction at 110-180° C. for 10-14 hours, and filtering and vacuum drying after the solvothermal reaction to obtain a pure nanodiamond film.
[0008] Preferably, the particle size of the nanodiamond is 5 to 500 nm.
[0009] Preferably, the mass ratio of the purified nano-diamond, potassium persulfate, and phosphorus pentoxide is 1:1:1. This ratio can ensure that the surface oxidation grafting process is complete, so that the degree of surface negative charge is high.
[0010] Preferably, in step 3, the solvent is selected from any one of methanol, ethanol or water.
[0011] Preferably, in step 3, the negatively charged nanodiamonds are uniformly dispersed in a solvent, and the concentration of the formed suspension is 0.1 to 3 g / mL.
[0012] Preferably, in step 3, the negatively charged nanodiamonds are uniformly dispersed in the solvent by ultrasound for 30 to 60 minutes.
[0013] Preferably, in step 3, the vacuum drying temperature is 50-80° C. and the time is 30-120 min.
[0014] Compared with the prior art, the present invention has the following advantages:
[0015] (1) The present invention purifies the surface of nanodiamonds by high-temperature treatment, and then grafts oxygen-containing functional groups on the surface of nanodiamonds by potassium persulfate and phosphorus pentoxide in a concentrated sulfuric acid environment to obtain nanodiamonds with negative surface charges. After dispersing the nanodiamonds in solvents such as methanol, the nanodiamonds are further synthesized by a solvothermal method to obtain a uniform and morphologically controllable pure nanodiamond film, which has great application potential in multiple fields such as electronics, optics, and biomedicine.
[0016] (2) The process of the present invention combines precise control with efficient synthesis, and achieves simple preparation of nanodiamond film by optimizing reaction conditions, especially the volume of solvent-thermal reaction solution. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a scanning electron microscope image of the 5 nm nanodiamond film prepared in Example 1 of the present invention.
[0018] Figure 2 This is the X-ray photoelectron spectrum of the 5 nm nanodiamond film prepared in Example 1 of the present invention.
[0019] Figure 3 This is the Raman spectrum of the 5 nm nano-diamond film prepared in Example 1 of the present invention.
[0020] Figure 4 This is a scanning electron microscope image of the 5 nm nanodiamond film prepared in Example 2 of the present invention.
[0021] Figure 5 This is a scanning electron microscope image of the 5 nm nanodiamond film prepared in Example 3 of the present invention.
[0022] Figure 6 This is a scanning electron microscope image of the 100nm nanodiamond film prepared in Example 4 of the present invention.
[0023] Figure 7 This is a scanning electron microscope image of the 100nm nanodiamond film prepared in Example 5 of the present invention.
[0024] Figure 8 This is a scanning electron microscope image of the 100nm nanodiamond film prepared in Example 6 of the present invention.
[0025] Fig. 9 This is a scanning electron microscope image of the 500nm nanodiamond film prepared in Example 7 of the present invention.
[0026] Fig.10 This is a scanning electron microscope image of the 500nm nanodiamond film prepared in Example 8 of the present invention.
[0027] Fig.11 This is a scanning electron microscope image of the 500nm nanodiamond film prepared in Example 9 of the present invention. DETAILED DESCRIPTION
[0028] The present application is further described below in conjunction with specific embodiments.
[0029] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.
[0030] 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 this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.
[0031] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.
[0032] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.
[0033] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.
[0034] Concentration, amount and other numerical data can be presented in range format herein.It should be understood that such range format is only used for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all single numerical values or sub-ranges contained in the range, just as each numerical value and sub-range are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including single numerals (such as 2,3,4) and sub-ranges (such as 1 to 3,2 to 4, etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values and ranges.In addition, no matter how the breadth of the described range or feature is, this explanation should be applicable.
[0035] The method for preparing a pure nano-diamond film of the present invention comprises the following steps:
[0036] Step 1, placing the nanodiamond in a tube furnace, heating it to 800-1200° C. and keeping it at that temperature for 5-10 hours to perform high-temperature surface purification treatment;
[0037] Step 2, add the nanodiamond, potassium persulfate and phosphorus pentoxide purified in step 1 into concentrated sulfuric acid respectively, and stir the reaction for 8 to 10 hours. Only with sufficient stirring reaction time can the negatively charged groups be firmly grafted on the surface of the nanodiamond. If the time is too short, the grafted bonds will easily break. After the reaction is completed, filter and wash the product with deionized water until it is neutral, and dry it to obtain negatively charged nanodiamond with a large number of oxygen-containing functional groups grafted on the surface;
[0038] Step 3, the negatively charged nano-diamond is uniformly dispersed in the solvent, and the concentration of the formed suspension is 0.1-3g / mL. The concentration of the dispersion prepared in this way is more uniform and easy to be ultrasonically dispersed. Too high a concentration will affect the dispersion of the nano-diamond, which is not conducive to the formation of a uniform nano-diamond film. The suspension is subjected to a solvent thermal reaction at 110-180°C for 10-14 hours, and the volume of the solvent thermal reaction solution is 30-50mL. This can not only make the nano-diamond film fully and uniformly deposited, but also regulate the saturated vapor pressure inside the reaction vessel, ensuring the optimization and stability of the reaction conditions. After the solvent thermal reaction is completed, the solution is filtered and vacuum dried to obtain a pure nano-diamond film.
[0039] The present invention first prepares a nano-diamond with a clean surface, and then adds potassium persulfate, phosphorus pentoxide and concentrated sulfuric acid. Since potassium persulfate and phosphorus pentoxide have a strong oxidizing effect in concentrated sulfuric acid, abundant negatively charged functional groups (hydroxyl, carboxyl) can be grafted on the surface of the clean nano-diamond. Then the obtained surface is negatively charged nano-diamond. The method uses a high-temperature solvent under high pressure as a reaction medium, and can react at a lower temperature, effectively reducing energy consumption. In the process of preparing pure nano-diamond film by solvothermal method, saturated vapor pressure is a key parameter. Using solvothermal method and controlling saturated vapor pressure to prepare pure nano-diamond film is an innovative and effective strategy. This method not only simplifies the preparation process and reduces costs, but also opens up a new way for preparing high-purity nano-diamond film. In addition, by accurately controlling the reaction conditions, it is expected to achieve precise regulation of the microstructure of the nano-diamond film, thereby improving its application performance in various fields.
[0040] Example 1
[0041] 1) Preparation of surface negatively charged nanodiamonds: First, commercial 5 nm nanodiamonds were heated at 1000°C for 5 h to clean the surface, and then 5 g of fired nanodiamonds, 5 g of potassium persulfate and 5 g of phosphorus pentoxide were dissolved in 50 mL of concentrated sulfuric acid and stirred for 8 h. The surface-grafted nanodiamonds with negatively charged oxygen-containing groups were washed with deionized water until neutral, and dried to obtain negatively charged nanodiamonds with a large number of surface-grafted oxygen-containing functional groups.
[0042] 2) Prepare pure nano-diamond film. Add 1 g of negatively charged nano-diamond into 1000 mL of methanol reagent and ultrasonicate for 60 min until evenly dispersed. Take 30 mL of the solution and add it into a solvent thermal synthesis reactor with a volume of 80 mL. React at 150°C for 12 hours. After the reaction is completed, filter and vacuum dry at 50°C to obtain pure nano-diamond film.
[0043] The scanning electron microscope, X-ray photoelectron spectroscopy and Raman spectrum of the nanodiamond film obtained in this example are shown in the attached drawings. Figure 1 , Figure 2 , Figure 3 As shown. Figure 1 It can be seen that the surface of the obtained nanodiamond film has slight protrusions and depressions, but has a complete and regular film structure. Figure 2 There are almost only C and O element peaks in the film, indicating that the prepared nanodiamond film has high purity. Figure 3 In the Raman spectrum of D / I G The value is 0.84, indicating that there are fewer defects.
[0044] Example 2
[0045] 1) The other processes are the same as in Example 1, except that the reaction conditions for the solvent thermal synthesis in this example are 150° C. for 9 hours.
[0046] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Figure 4 Part of the membrane structure can be seen, but it is not complete.
[0047] Example 3
[0048] 1) The other processes are the same as in Example 1, except that the reaction conditions for the solvent thermal synthesis in this example are 120° C. for 12 hours.
[0049] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Figure 5 As shown, it can be seen that the membrane structure is relatively complete, but the surface is uneven, with many protrusions and depressions, and cracks.
[0050] Example 4
[0051] 1) The other processes are the same as in Example 1, except that the commercial nanodiamond particles used in this example have a particle size of 100 nm.
[0052] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Figure 6 As shown. Its particle size is slightly larger, the membrane surface is relatively flat, and there are fewer protrusions or depressions.
[0053] Example 5
[0054] 1) The other processes are the same as Example 1, except that the commercial nanodiamond particles used in this example have a particle size of 100 nm, and the reaction conditions for solvent thermal synthesis are 150° C. for 9 hours.
[0055] The scanning electron microscope image of the nanodiamond film obtained in this example is as follows Figure 7 As shown, it can be seen that the prepared nanodiamond has a relatively complete film structure, but there are large depressions on the surface.
[0056] Example 6
[0057] 1) The other processes are the same as Example 1, except that the commercial nanodiamond particle size used in this example is 100 nm, and the reaction conditions for solvent thermal synthesis are 120° C. for 12 hours.
[0058] The scanning electron microscope image of the nanodiamond film obtained in this example is as follows Figure 8 As shown, it can be seen that the prepared nanodiamond film has a complete film structure, with only some protrusions on the surface.
[0059] Example 7
[0060] 1) The other processes are the same as in Example 1, except that the commercial nanodiamond particles used in this example have a particle size of 500 nm.
[0061] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Fig. 9 As shown in the figure, it can be seen that the diamond film is curled, not very smooth, and cannot form a complete film structure.
[0062] Example 8
[0063] 1) The other processes are the same as Example 1, except that the commercial nanodiamond particle size used in this example is 500 nm, and the reaction conditions for solvent thermal synthesis are 150° C. for 9 hours.
[0064] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Fig.10 The prepared nanodiamond film exhibits an appearance similar to "pebble-like" paving, with each particle tightly but not completely fused together to form a continuous but slightly rough layer.
[0065] Example 9
[0066] 1) The other processes are the same as Example 1, except that the commercial nanodiamond particle size used in this example is 500 nm, and the reaction conditions for solvent thermal synthesis are 120° C. for 12 hours.
[0067] The scanning electron microscope image of the nanodiamond film obtained in this example is shown in the attached figure. Fig.11 As shown in Figure 2, it can be seen that the prepared nanodiamond film is relatively complete, but the surface nanodiamonds are relatively large in agglomeration and have many protrusions.
[0068] Comparative Example 1
[0069] Without performing negative charge grafting treatment on the surface of nanodiamond, 30 g of nanodiamond was directly added into 1000 mL of deionized water and ultrasonicated for 60 min, but no suspension with good dispersion could be obtained.
Claims
1. A method for preparing a pure nano-diamond film, characterized in that: The following steps are involved: Step 1, placing the nanodiamond in a tube furnace, heating it to 800-1200°C and keeping it at that temperature for 5-10 hours to perform high-temperature surface purification treatment; Step 2, adding the nanodiamond, potassium persulfate and phosphorus pentoxide purified in step 1 into concentrated sulfuric acid respectively, stirring and reacting for 8-10 hours, filtering, washing the product with deionized water until it is neutral, and drying to obtain negatively charged nanodiamond with a large number of oxygen-containing functional groups grafted on the surface; Step 3: Evenly disperse the negatively charged nanodiamonds in the solvent, and subject the formed suspension to a solvothermal reaction at 110-180° C. for 10-14 hours. After the solvothermal reaction, filter and vacuum dry to obtain a pure nanodiamond film.
2. The method according to claim 1, characterized in that The particle size of nanodiamond is 5~500 nm.
3. The method according to claim 1, characterized in that The mass ratio of the purified nano-diamond, potassium persulfate and phosphorus pentoxide is 1:1:
1.
4. The method according to claim 1, characterized in that In step 3, the solvent is selected from any one of methanol, ethanol or water.
5. The method according to claim 1, characterized in that In step 3, the negatively charged nanodiamonds are uniformly dispersed in a solvent to form a suspension having a concentration of 0.1-3 g / mL.
6. The method according to claim 1, characterized in that In step 3, the negatively charged nanodiamonds are uniformly dispersed in the solvent by ultrasonication for 30 to 60 minutes.
7. The method according to claim 1, characterized in that In step 3, the vacuum drying temperature is 50-80°C and the time is 30-120 min.
8. A pure nano-diamond film prepared by the method according to any one of claims 1 to 7.