A method for depositing metal nanoparticles on powdered boron nitride nanotubes

Abstract

The application relates to the field of nanometer processing technology, and particularly relates to a method for depositing metal nanoparticles on powdery boron nitride nanotubes, which comprises the following steps: S1, adding boron nitride nanotube powder and a functionalization reagent into a high-pressure kettle or a three-necked bottle flask, and performing ultrasonic and water bath heating; S2, evaporating liquid in the high-pressure kettle or the three-necked bottle flask, adding an acidic solution, and performing filtration, cleaning and drying treatment; S3, under a high-purity nitrogen environment, adding boron nitride nanotube powder with active functional groups on the surface and a surfactant into a solvent, preheating, weighing metal source precursors according to a proportion, and adding the metal source precursors into the solvent, and reacting for 20-50 min; and S4, performing filtration treatment on the above reaction liquid, and then performing cleaning, vacuum filtration treatment and vacuum drying treatment on the solid, so as to obtain boron nitride nanotube powder coated with metal nanoparticles on the surface. The deposition method can uniformly deposit metal nanoparticles on the powdery boron nitride nanotubes.

Description

Technical Field

[0001] This invention relates to the field of nanofabrication technology, and in particular to a method for depositing metal nanoparticles on powdered boron nitride nanotubes. Background Technology

[0002] In recent years, tubular nanoparticles such as boron nitride nanotubes (BNNTs) have attracted much attention from researchers due to their chemical, mechanical, and thermal properties. Despite these key characteristics, the inert surfaces of these nanoparticles still require modification to prepare them for any potential future applications. In this sense, functional groups can be grafted onto the inert surfaces of these particles using a grafting method, thereby functionalizing them and enabling them to adhere to polymers, nanoparticles, and even thin films.

[0003] It is well known that coating boron nitride nanotubes with metal nanoparticles is beneficial for applications in photocatalysis, biolabeling, optoelectronics, and nanofluidics. Among these, boron nitride nanotubes coated with titanium (Ti) or tungsten (W) have a wider range of applications in additive manufacturing, aerospace, and electronics. Currently, the deposition of titanium or tungsten on nanoparticles is usually achieved by using corresponding oxides. This involves first depositing TiO2 or WO3 powder or other oxides onto boron nitride nanotubes, followed by a hydrogen-assisted magnesothermic or calcothermic reduction process to reduce these oxides to metallic Ti and W on the surface of the boron nitride nanotubes through a phase transition. However, this reduction method is not only complex and involves numerous steps, but also requires additional experimental equipment, such as electrochemical equipment. Furthermore, it demands very high safety monitoring during the preparation process, requiring various safety tests, such as hydrogen leakage tests. This significantly increases the preparation cost, thereby reducing the economic efficiency of this method. Therefore, it is necessary to develop an alternative method for depositing and coating Ti, W, and other metal nanoparticles onto powdered boron nitride nanotubes for decoration. However, there is currently no research on the direct deposition and coating of Ti, W, and other metals onto powdered boron nitride nanotubes. Since boron nitride has two crystal forms, diamond and graphite, the graphite-type boron nitride crystal is also known as "white graphite" due to its structure being similar to graphene. Therefore, it might be possible to refer to methods for preparing metal coatings on graphene surfaces, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), to design a method that can directly deposit and coat Ti, W, and other metal coatings onto powdered boron nitride nanotubes.

[0004] This invention provides a method for depositing metal nanoparticles on powdered boron nitride nanotubes, thereby solving the problems of existing deposition methods being unable to directly deposit or coat metal coatings on powdered boron nitride nanotubes. Summary of the Invention

[0005] The purpose of this invention is to provide a method for depositing metal nanoparticles on powdered boron nitride nanotubes, thereby solving the problems of existing deposition methods being unable to directly deposit or coat metal coatings on powdered boron nitride nanotubes.

[0006] The technical solution of this invention is: a method for depositing metal nanoparticles on powdered boron nitride nanotubes, comprising the following steps: Preferably, in step S1, the boron nitride nanotube powder to be treated and the functionalizing reagent are weighed out according to the proportion, and the weighed boron nitride nanotube powder and functionalizing reagent are added to an autoclave or a three-necked flask. Then, the autoclave or three-necked flask is sealed and placed in an ultrasonic instrument for ultrasonic treatment. After ultrasonic treatment for 3-10 minutes, it is transferred to a water bath at a temperature of 100-120℃ and heated in a water bath for 20-30 hours to perform functionalization treatment on the boron nitride nanotube powder. S2. After the functionalization process is completed, the liquid phase in the autoclave or three-necked flask is evaporated to separate the solid and liquid phases. Then, an acidic solution is added to the autoclave or three-necked flask, and the mixture is stirred or sonicated for 5-20 minutes to ensure that the acidic solution is mixed evenly with the solid phase in the autoclave or three-necked flask to form a mixture. The mixture is then filtered to obtain a filter residue containing boron nitride nanotube powder with active functional groups on its surface. The filter residue is then washed and dried several times with pure water and acetone to obtain boron nitride nanotube powder with active functional groups on its surface. S3. Under a high-purity nitrogen atmosphere, the obtained boron nitride nanotube powder with active functional groups on the surface and the surfactant are added to the solvent and mixed evenly. The mixture is then preheated to 100-150℃. After that, the metal source precursor is weighed according to the molar ratio of boron nitride nanotube powder with active functional groups on the surface to the metal source precursor of 1:(1-2) and added to the solvent. The mixture is heated under reflux and the reaction is stopped after 20-50 min. The reaction solution is then cooled to room temperature. S4. The above reaction solution is filtered to obtain a solid containing boron nitride nanotube powder coated with metal nanoparticles. Then, the solid is washed with deionized water and subjected to vacuum filtration and vacuum drying in sequence to obtain boron nitride nanotube powder coated with metal nanoparticles.

[0007] Preferably, in step S1, the mass ratio of the boron nitride nanotube powder to the functionalized reagent is (4-5):1; The functionalizing reagent is any one or more of hydrogen peroxide, water, and ozone.

[0008] Preferably, in step S2, the acidic solution is any one of HNO3, H2SO4, fuming sulfuric acid, a mixture of HNO3 and H2SO4, or a mixture of HNO3, H2SO4 and fuming sulfuric acid.

[0009] Preferably, in step S2, the cleaning process includes treating the filter residue several times with pure water and acetone; the drying process uses a vacuum drying oven.

[0010] Preferably, in step S3, the surfactant is a mixture of oleic acid and trioctylphosphine oxide; The metal source precursor is titanium isopropoxide and tungsten hexacarbonyl; The solvent is THF, diphenyl ether, or toluene.

[0011] Preferably, in step S3, the molar ratio of boron nitride nanotube powder to metal source precursor is 1:(1-1.5).

[0012] Compared with the prior art, the advantages of the present invention are: This invention provides a method for depositing metal nanoparticles on powdered boron nitride nanotubes. This deposition method activates B sites on the powdered boron nitride nanotubes through functionalization treatment, grafts oxygen-containing functional groups onto the surface of the boron nitride nanotubes, and enhances the polarity of the surface, thus allowing direct deposition and decoration of the surface with metal nanoparticles such as Ti and W. This deposition method not only enables uniform deposition of metal nanoparticles on the powdered boron nitride nanotubes, but also allows adjustment of the metal content deposited on the surface of the powdered boron nitride nanotubes by adjusting the concentration of the metal precursor, and optimizes the oxidation degree of the deposited metal particles by adjusting the proportion of surfactant added. Furthermore, this deposition method is simple to operate, requires no additional experimental equipment, and has low requirements for safety monitoring during the deposition process, thus helping to save on preparation costs. It solves the problem that existing deposition methods cannot directly deposit or coat metal coatings on powdered boron nitride nanotubes. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart of the experimental procedures for preparing functionalized boron nitride nanotubes according to the present invention. Figure 2 This is a TEM micrograph of the functionalized boron nitride nanotubes prepared in Example 1 of the present invention; Figure 3 Comparison of EDX analysis at positions 007 and 008 on the functionalized boron nitride nanotubes prepared in Example 1 of the present invention; Figure 4 This is a comparison of Fourier transform infrared spectra of 10 points on the unfunctionalized boron nitride nanotubes in Example 2 of the present invention. Figure 5 This is a comparison of Fourier transform infrared spectra of 10 points on the functionalized boron nitride nanotubes prepared in Example 2 of the present invention. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments: This application provides a method for depositing metal nanoparticles on powdered boron nitride nanotubes, comprising the following steps: S1, such as Figure 1 As shown, the boron nitride nanotube powder and functionalizing reagent to be treated are weighed out according to the specified proportions, and then added to a reaction vessel such as an autoclave or a three-necked flask. The autoclave or three-necked flask is then sealed and placed in an ultrasonic bath for ultrasonic treatment for 3-10 minutes to ensure that the boron nitride nanotube powder and functionalizing reagent are mixed evenly. Afterward, the autoclave or three-necked flask is transferred to a water bath for heating at 100-120℃ for 20-30 hours to functionalize the boron nitride nanotube powder. The mass ratio of boron nitride nanotube powder to functionalizing reagent is (4-5):1. The functionalizing reagent can be one or more oxidants such as hydrogen peroxide, water, and ozone, for example, a combination of ozone and water. The surface of boron nitride nanotube powder particles is inert. To directly coat these particles with metal nanoparticles such as Ti and W, chemical treatment of the boron nitride nanotube powder is necessary. This involves activating the B sites on the boron nitride nanotube powder through grafting oxygen-containing functional groups. After functionalization, hydroxyl groups bind to the B sites, while N sites form -NH groups, enhancing the polarity of the boron nitride nanotube powder particles. This allows for direct decoration with metal nanoparticles such as Ti and W. The reason for prioritizing coating with Ti and W nanoparticles is that intermediate phases form at the interfaces between Ti and other metal compounds. For example, when Ti nanoparticles are deposited on boron nitride nanotubes in aluminum alloys, TiB and TiN phases can be formed, allowing the Ti nanoparticles to act as a bridge between the reinforcing particles and the Al matrix, thereby improving the mechanical properties of the coating. Furthermore, this deposition method not only promotes heat transfer in the boron nitride nanotubes, preventing thermal degradation, but also increases the hardness of the final alloy by forming new phases.

[0015] S2. After the functionalization process is completed, open the sealed autoclave or three-necked flask and evaporate the liquid phase in the autoclave or three-necked flask to separate the solid phase from the liquid phase, obtaining crude boron nitride nanotube powder with active functional groups on the surface. Then, add an appropriate amount of acidic solution to the autoclave or three-necked flask to remove impurities from the crude boron nitride nanotube powder with active functional groups. Stir or sonicate for 5-20 minutes to mix the acidic solution with the crude boron nitride nanotube powder with active functional groups evenly and form a mixture. Then, filter the mixture to obtain a filter residue containing boron nitride nanotube powder with active functional groups. Then, wash the filter residue several times with pure water and acetone. Finally, place the filter residue in a vacuum oven for drying to obtain boron nitride nanotube powder with active functional groups on the surface. During the functionalization process of boron nitride nanotube powder in the autoclave or three-necked flask, N2H4 is generated. During the evaporation and removal of the liquid phase in the autoclave or three-necked flask, some N2H4 and H2O2 are coated and remain in the solid phase. Adding an acidic solution can remove the coated and remaining N2H4 and H2O2 in the solid phase. The acidic solution is HNO3, H2SO4, fuming sulfuric acid, a mixture of HNO3 and H2SO4, or a mixture of HNO3, H2SO4 and fuming sulfuric acid. The filter residue obtained by filtration is washed several times with pure water and acetone to remove the acidic solvent and other soluble impurities in the filter residue.

[0016] S3. Under a high-purity nitrogen atmosphere, the obtained boron nitride nanotube powder with active functional groups on the surface and the surfactant are added to the solvent and mixed evenly. The mixture is then preheated to 100-150℃, and the solvent is kept under continuous reflux to ensure thorough mixing between the solvent and the boron nitride nanotube powder with active functional groups. After that, the metal source precursor is weighed according to a molar ratio of 1:(1-2) between the boron nitride nanotube powder with active functional groups and the metal source precursor, and added to the solvent. The mixture is heated under reflux and reacted for 20-50 minutes. The color change of the solution is observed. The reaction is then stopped, and the reaction solution is cooled to room temperature. The solvent is selected from THF, diphenyl ether, toluene, etc.; the surfactant can be selected from a mixture of stearic acid, oleic acid, lauric acid, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, etc., and trioctylphosphine oxide; the purpose of adding the surfactant during the deposition of metal nanoparticles from boron nitride nanotube powder with active functional groups on the surface is to reduce the possibility of oxidation of the deposited metal nanoparticles; the molar ratio of boron nitride nanotube powder with active functional groups on the surface to the surfactant is 1:(0.01-0.5); the metal precursor can be titanium isopropoxide (IV), titanium acetylacetonate, tungsten hexacarbonyl (W(CO)6), or a binuclear tungsten carbonyl nitroso coordination compound (W2(NO)2(CO)). n )wait.

[0017] S4. The above reaction solution is filtered to obtain a solid containing boron nitride nanotube powder coated with metal nanoparticles. Then, the filtered solid is placed in a container filled with deionized water for washing. Next, vacuum filtration is performed to obtain a pure solid. The pure solid is then placed in a vacuum oven for vacuum drying to obtain boron nitride nanotube powder coated with metal nanoparticles.

[0018] The method provided in this application is an improvement on existing chemical vapor deposition (CVD) methods for coating chemical coatings on graphene, based on the similarity between graphene and white graphene (BN). While traditional physical vapor deposition (PVD) methods, such as magnetron sputtering, offer advantages such as lower heat requirements, no damage to substrates with insufficient thermal resistance, and higher sputtering yield, the powder morphology of boron nitride nanotubes is a major limiting factor in coating. During the evacuation and degassing of the sputtering chamber, powder may fly away. Furthermore, sputtering coatings are pseudo-conformal and cannot guarantee uniform deposition. Therefore, to overcome these problems, this application provides the aforementioned chemical deposition method as an alternative. Extensive experimental research shows that the chemical deposition method provided in this application can adjust the metal content deposited on the surface of powdered boron nitride nanotubes by adjusting the concentration of the metal precursor; and can optimize the oxidation degree of the deposited metal by changing the amount of the mixture of oleic acid and trioctylphosphine oxide. In addition, experimental research has found that the chemical deposition method provided in this application can also be applied to the direct deposition of metal nanoparticles on the surface of boron nitride nanosheets.

[0019] Example 1

[0020] S1. Weigh out powdered boron nitride nanotubes and 30% H2O2 solution in a mass ratio of 4:1. Add the weighed boron nitride nanotube powder and 30% H2O2 solution to an autoclave. Then, seal the autoclave and place it in an ultrasonic instrument for ultrasonication for 5 minutes to fully mix the hydrogen peroxide and boron nitride nanotube powder. After that, transfer it to a water bath at 100℃ and heat it for 24 hours to perform functionalization treatment on the boron nitride nanotube powder.

[0021] S2. After the functionalization process is completed, the autoclave is opened, and the liquid phase in the autoclave is evaporated to separate the solid phase from the liquid phase. Then, a mixture of HNO3, H2SO4, and fuming sulfuric acid is added to the autoclave to remove impurities such as N2H4 and H2O2 coated in the solid phase. The mixture is sonicated for 10 minutes to mix the acidic solution with the solid phase in the autoclave to form a mixture. The mixture is then filtered to obtain a filter residue containing boron nitride nanotube powder with active functional groups on its surface. The filter residue is then washed several times with pure water and acetone in sequence, and then dried in a vacuum oven to obtain boron nitride nanotube powder with active functional groups on its surface, i.e., powdered and functionalized boron nitride nanotubes. Finally, the prepared functionalized boron nitride nanotubes are taken and detected and analyzed using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX).

[0022] S3. Under a high-purity nitrogen atmosphere, the obtained boron nitride nanotube powder with active functional groups on its surface, the mixture of oleic acid and trioctylphosphine oxide were added to THF solvent. After mixing evenly, the mixture was preheated to 100°C and the solvent was continuously refluxed in the reaction vessel. Then, titanium isopropoxide (IV) was weighed according to the molar ratio of boron nitride nanotube powder with active functional groups on its surface to titanium isopropoxide (IV) of 1:1.5 and added to the solvent. The mixture was heated to reflux and reacted for 30 min. The reaction was then stopped and the reaction solution was cooled to room temperature.

[0023] S4. The above reaction solution is filtered to obtain a solid containing boron nitride nanotube powder coated with Ti nanoparticles. Then, the solid is washed with deionized water and vacuum filtered and vacuum dried in sequence to obtain boron nitride nanotube powder coated with Ti nanoparticles.

[0024] like Figure 2 , Figure 3 As shown, after functionalization, oxygen- and nitrogen-containing functional groups are formed on the surface of boron nitride nanotubes.

[0025] Example 2

[0026] S1. Weigh out powdered boron nitride nanotubes and 30% H2O2 solution in a mass ratio of 5:1, and use Fourier transform infrared spectroscopy (FTIR) to detect and analyze the boron nitride nanotube powder. Then, add the weighed boron nitride nanotube powder and 30% H2O2 solution to an autoclave. Seal the autoclave and place it in an ultrasonic instrument for ultrasonication for 5 minutes to fully mix the hydrogen peroxide and boron nitride nanotube powder. Then, transfer it to a water bath at 120℃ and heat it for 24 hours to functionalize the boron nitride nanotube powder.

[0027] S2. After the functionalization process is complete, the autoclave is opened, and the liquid phase in the autoclave is evaporated to separate the solid and liquid phases. Then, a mixture of HNO3, H2SO4, and fuming sulfuric acid is added to the autoclave to remove impurities such as N2H4 and H2O2 coated on the solid phase. The mixture is ultrasonicated for 10 minutes to ensure uniform mixing of the acidic solution with the solid phase in the autoclave, forming a mixture. The mixture is then filtered to obtain a filter residue containing boron nitride nanotube powder with active functional groups on its surface. This residue is then washed several times with pure water and acetone, followed by drying in a vacuum oven to obtain boron nitride nanotube powder with active functional groups on its surface. A small amount of this powder is then taken and analyzed using Fourier transform infrared spectroscopy (FTIR). Comparing the chemical composition of unfunctionalized boron nitride nanotubes with that of functionalized boron nitride nanotubes reveals that... Figure 4 , Figure 5 As shown, after functionalization, functional groups are uniformly distributed on the boron nitride nanotubes; and according to the comparison of the detection results of 10 different sites, the functional groups on the functionalized boron nitride nanotubes have high uniformity.

[0028] S3. Under a high-purity nitrogen atmosphere, the obtained boron nitride nanotube powder with active functional groups on its surface, the mixture of oleic acid and trioctylphosphine oxide were added to xylene solvent. After mixing evenly, the mixture was preheated to 130°C and the solvent was continuously refluxed in the reaction vessel. Then, tungsten hexacarbonyl was weighed according to the molar ratio of boron nitride nanotube powder with active functional groups on its surface to tungsten hexacarbonyl of 1:1.3 and added to the solvent. The mixture was heated to reflux and reacted for 30 minutes. The reaction was then stopped and the reaction solution was cooled to room temperature.

[0029] S4. The above reaction solution is filtered to obtain a solid containing boron nitride nanotube powder coated with W nanoparticles. Then, the solid is washed with deionized water and subjected to vacuum filtration and vacuum drying in sequence to obtain boron nitride nanotube powder coated with W nanoparticles.

[0030] Comparing the chemical composition detection results of unfunctionalized boron nitride nanotubes with those of functionalized boron nitride nanotubes reveals that, for example... Figure 4 , Figure 5As shown, after functionalization, functional groups are uniformly distributed on the boron nitride nanotubes. Furthermore, a comparison of the detection results at 10 different sites shows that the functional groups on the functionalized boron nitride nanotubes exhibit high uniformity of distribution. This allows for the uniform deposition of metal nanoparticles onto the boron nitride nanotubes. The chemical deposition method provided in this application can prepare powdered boron nitride nanotubes with a surface coated with metal nanoparticles that meet the deposition requirements. Simultaneously, the deposition method provided in this application not only preserves the microstructure of the powdered boron nitride nanotubes but also forms strong TiB2 and WB2 phases at the interface of the particle-coated metal layer during the deposition process, effectively improving the hardness and tensile strength of any possible Ti or W deposited boron nitride nanotubes embedded in the alloy.

[0031] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. A method for depositing metal nanoparticles on powdered boron nitride nanotubes, characterized in that, Includes the following steps: S1. Weigh out the boron nitride nanotube powder and functionalizing reagent according to the proportion, and add the weighed boron nitride nanotube powder and functionalizing reagent into an autoclave or a three-necked flask. Then, seal the autoclave or three-necked flask and place it in an ultrasonic instrument for ultrasonic treatment. After ultrasonic treatment for 3-10 minutes, transfer it to a water bath at a temperature of 100-120℃ and heat it in a water bath for 20-30 hours to perform functionalization treatment on the boron nitride nanotube powder. S2. After the functionalization process is completed, the liquid phase in the autoclave or three-necked flask is evaporated to separate the solid and liquid phases. Then, an acidic solution is added to the autoclave or three-necked flask, and the mixture is stirred or sonicated for 5-20 minutes to mix the acidic solution with the solid phase in the autoclave or three-necked flask to form a mixture. The mixture is then filtered to obtain a filter residue containing boron nitride nanotube powder with active functional groups on its surface. The filter residue is then washed and dried several times with pure water and acetone to obtain boron nitride nanotube powder with active functional groups on its surface. S3. Under a high-purity nitrogen atmosphere, the obtained boron nitride nanotube powder with active functional groups on the surface and the surfactant are added to the solvent and mixed evenly. The mixture is then preheated to 100-150℃. After that, the metal source precursor is weighed according to the molar ratio of boron nitride nanotube powder with active functional groups on the surface to the metal source precursor of 1:(1-2) and added to the solvent. The mixture is heated under reflux and reacted for 20-50 min. The reaction is then stopped and the reaction solution is cooled to room temperature. S4. The above reaction solution is filtered to obtain a solid containing boron nitride nanotube powder coated with metal nanoparticles. Then, the solid is washed with deionized water and subjected to vacuum filtration and vacuum drying in sequence to obtain boron nitride nanotube powder coated with metal nanoparticles.

2. The method for depositing metal nanoparticles on powdered boron nitride nanotubes according to claim 1, characterized in that, In step S1, the mass ratio of the boron nitride nanotube powder to the functionalized reagent is (4-5):1; The functionalizing reagent is any one or more of hydrogen peroxide, water, and ozone.

3. The method for depositing metal nanoparticles on powdered boron nitride nanotubes according to claim 1, characterized in that, In step S2, the acidic solution is any one of HNO3, H2SO4, fuming sulfuric acid, a mixture of HNO3 and H2SO4, or a mixture of HNO3, H2SO4 and fuming sulfuric acid.

4. The method for depositing metal nanoparticles on powdered boron nitride nanotubes according to claim 1, characterized in that, In step S2, the cleaning process includes treating the filter residue several times with pure water and acetone; the drying process uses a vacuum drying oven.

5. The method for depositing metal nanoparticles on powdered boron nitride nanotubes according to claim 1, characterized in that, In step S3, the surfactant is a mixture of oleic acid and trioctylphosphine oxide; The metal source precursor is titanium isopropoxide and tungsten hexacarbonyl; The solvent is THF, diphenyl ether, or toluene.

6. The method for depositing metal nanoparticles on powdered boron nitride nanotubes according to claim 1, characterized in that, In step S3, the molar ratio of boron nitride nanotube powder to metal source precursor is 1:(1-1.5).

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