CN102807249B - Method for controlling shapes of zinc oxide nanoparticles - Google Patents

Abstract

The invention provides a method for controlling shapes of zinc oxide nanoparticles. The method includes enabling N,N-dimethylformamide, water and zinc nitrate hexahydrate to contact with one another at the temperature ranging from 110 DEG C to 140 DEG C. The method is characterized in that the zinc oxide nanoparticles with different shapes can be obtained by controlling the proportion of the N,N-dimethylformamide to the water and contacting time of the N,N-dimethylformamide, the water and the zinc nitrate hexahydrate. By the method, the zinc oxide nanoparticles with controllable shapes and controllable defect concentrations can be prepared, and surface stabilizers are omitted in the preparation method.

Description

A method of controlling the morphology of zinc oxide nanoparticles

technical field

The invention relates to a method for controlling the morphology of zinc oxide nanoparticles.

Background technique

Compared with ordinary zinc oxide, nano zinc oxide has better physical and chemical properties. Especially in the aspects of piezoelectricity, fluorescence and photocatalysis. These excellent properties make nano-zinc oxide have potential value in energy, environment and industrial catalysis and other application fields, so it has attracted widespread attention of scientific researchers. Due to the large number of defects in the surface structure of nano-zinc oxide, it plays a significant role in photocatalytic degradation of organic pollutants. The bandgap energy Eg of zinc oxide is 3.2eV, and any ultraviolet light source with a wavelength lower than 387.5nm (λg=1240/Eg) can be used as its excitation light source. When the nano-zinc oxide material is irradiated by photons with energy greater than the forbidden band width, the electrons transition from the valence band to the conduction band, generating electron-hole pairs. The electrons are reducing and the holes are oxidizing. Photogenerated e ^- and h ⁺ can not only react with the reactants directly, but also react with other electron acceptors or donors adsorbed on the catalyst. The hole reacts with the ^OH on the surface of the nano-zinc oxide material to generate highly oxidizing OH radicals, and the active OH can oxidize organic fuel pollutants in water into CO ₂ and H ₂ O. Due to the different surface structures of different crystal faces of zinc oxide, there are large differences in the stability and the number of surface defects, resulting in different photocatalytic effects of zinc oxide with different crystal faces, for example: Hajime Haneda (Morphologies of zinc oxide particles and their effects on photocatalysis, Chemosphere, 2003, 5, 129-137) group used different methods to synthesize zinc oxide nanocrystals with different shapes, and found that their photocatalytic activity was closely related to the surface morphology. For this reason, the morphology and surface structure control of ZnO nanomaterials has become a major research hotspot. Many preparation methods of ZnO nanoparticles with different surface structures and morphologies have been developed. The most typical are vapor deposition and wet chemical methods. Vapor deposition methods are rarely used in photocatalyst research due to their shortcomings such as poor reproducibility and incapability of mass production. Wet chemical methods are a good choice for the large-scale preparation of ZnO nanomaterials with controllable morphology and structure. However, most of the current wet chemical methods utilize the adsorption of surface stabilizers to control the morphology of ZnO nanomaterials. The surface of the ZnO nanomaterial prepared in this way is affected by the stabilizer and its photocatalytic activity is affected and reduced. Therefore, how to avoid the influence of surface stabilizers on the surface structure of ZnO by selecting appropriate synthesis conditions has become a key challenge for the application of ZnO nanomaterials in the field of photocatalysis in the future.

Contents of the invention

The purpose of the present invention is to provide a method capable of controlling the morphology of zinc oxide nanoparticles, by which zinc oxide nanocrystalline particles with controllable morphology and defect concentration can be prepared, and no need to use surface stabilizer.

After in-depth research, the inventors of the present invention found that by controlling the ratio of N,N-dimethylformamide and water and the contact time of N,N-dimethylformamide, water and zinc nitrate hexahydrate, it is possible to prepare Zinc oxide nano crystal particles with controllable shape and controllable defect concentration.

That is, the present invention provides a method for controlling the morphology of zinc oxide nanoparticles, the method comprising contacting N,N-dimethylformamide, water and zinc nitrate hexahydrate at a temperature of 110-140°C, wherein, By controlling the ratio of N, N-dimethylformamide and water and the contact time of N, N-dimethylformamide, water and zinc nitrate hexahydrate, zinc oxide nanoparticles with different morphologies were obtained.

Compared with the prior art, the present invention has the following advantages:

1. The method of the present invention is simple and easy to operate, only using solvothermochemical synthesis of zinc oxide nano crystal particles, and fewer steps are required.

2. The present invention allows zinc nitrate hexahydrate to be hydrolyzed spontaneously in N, N-dimethylformamide, without adding other substances that can provide hydroxide, and requires less reaction substances.

3. The zinc oxide nano crystal particles prepared by the present invention do not add any surface stabilizer, so that the active sites are not covered, which helps to enhance its catalytic efficiency as a catalyst.

4. The surface defect concentration of the three zinc oxide nanocrystalline particles prepared by the present invention is controlled by the amount of reaction water, and the growth of its crystal plane is also related to the amount of water. Zinc oxide with different photocatalytic activities and luminescent properties can be prepared by simply adjusting the amount of water nanomaterials.

Description of drawings

Fig. 1 is the scanning electron microscope picture of the zinc oxide nanoparticle prepared by the present invention, wherein, a and b in Fig. 1 are the scanning electron microscope picture of the rod-shaped zinc oxide nanoparticle prepared in embodiment 1; c among Fig. 1 And d is the scanning electron microscope picture of the truncated hexagonal pyramid-shaped zinc oxide nanoparticle prepared in embodiment 2; e and f among Fig. 1 are the scanning electron microscope of the multilayer discoid zinc oxide nanoparticle prepared in embodiment 3 picture.

FIG. 2 is an X-ray photoelectron energy spectrum O1s peak diagram of rod-shaped zinc oxide nanoparticles prepared in Example 1. FIG.

3 is the X-ray photoelectron spectrum O1s peak diagram of the truncated hexagonal pyramid-shaped zinc oxide nanoparticles prepared in Example 2.

FIG. 4 is an X-ray photoelectron spectrum O1s peak diagram of the multilayer discotic zinc oxide nanoparticles prepared in Example 3. FIG.

Detailed ways

The invention provides a method for controlling the morphology of zinc oxide nanoparticles, the method comprising contacting N,N-dimethylformamide, water and zinc nitrate hexahydrate at a temperature of 110-140°C, wherein, by controlling The ratio of N,N-dimethylformamide to water and the contact time of N,N-dimethylformamide, water and zinc nitrate hexahydrate were used to obtain ZnO nanoparticles with different morphologies.

According to the method of the present invention, it is possible to provide a zinc oxide nanocrystal particle with a rod shape, a truncated hexagonal pyramid shape or a multi-layer disk shape, the size of the zinc oxide nanocrystal particle is nanoscale, and its surface is There are significant differences in the concentration of defects contained. The zinc oxide nanocrystalline particles are synthesized spontaneously by adding different amounts of water (H ₂ O) in N,N-dimethylformamide solvent, without adding other reagents.

The above-mentioned preparation mechanism may be speculated as follows: N,N-dimethylformamide is a substance with a high dielectric constant, because this high dielectric constant makes it easy to separate charges, making it a better solvent. When N,N-dimethylformamide is mixed with water, a polar, aprotic mixed solvent is obtained, which is a suitable medium for the spontaneous hydrolysis of metal ions. In the present invention, a mixture of N,N-dimethylformamide and H ₂ O is used as a solvent to make Zn(NO ₃ ) ₂ ·6H ₂ O spontaneously hydrolyzed and condensed to form zinc oxide nanocrystalline particles. There is no need to add other reagents that can provide hydroxide (such as sodium hydroxide, ammonia water, etc.) and any surface stabilizer, so that the active sites on the ZnO surface are not covered. The process of this hydrolysis can be represented by equations (1), (2), (3):

Zn ²⁺ +4OH ^- ＝Zn(OH) ₄ ^2- (2)

According to the method of the present invention, the temperature is preferably 115-125°C.

According to the method of the present invention, the quality of the zinc nitrate hexahydrate and the amount of N,N-dimethylformamide and water can vary in a wide range. Generally speaking, the quality of the zinc nitrate hexahydrate and the total volume ratio of N, N-dimethylformamide and water are 5-10: 1g/L; Considering the cost, the zinc nitrate hexahydrate is preferably The total volume ratio of mass to N,N-dimethylformamide and water is 7-8:1g/L.

In the present invention, it is necessary to control the ratio of N,N-dimethylformamide and water. The reasons may be:

(1) Zinc oxide nanocrystalline particles with rod-shaped morphology: the synthesis conditions contain sufficient water, so that the hydrolysis reaction can be fully carried out. On the other hand, since the top surface is a polar surface, which belongs to the high-energy surface and has high activity, based on the minimization of surface energy, this high-energy surface is easy to grow, so the growth rate of ZnO in the axial direction is faster than that in the lateral direction. The sufficient reaction of hydrolysis ensures sufficient nucleation and growth of zinc oxide, then the relative speed ratio between the axial direction and the transverse direction tends to a constant value, so that the final rod-shaped morphology is formed.

(2) Zinc oxide nanocrystalline particles with truncated hexagonal pyramid shape: the synthesis conditions contain an appropriate amount of water. During the growth process, as the amount of water gradually decreases as the reaction proceeds, the growth rate begins to slow down, making the axis The relative growth rates in the vertical and lateral directions gradually changed, eventually leading to the formation of hexagonal pyramidal ZnO nanocrystals.

(3) Zinc oxide nanocrystalline particles with multilayer discoid morphology: due to the anhydrous or very small amount of water in its synthesis conditions, the water of the hydrolysis reaction comes from the crystal water in zinc nitrate hexahydrate. Under the condition of extreme lack of water, the nucleation and growth rate are greatly limited, the absolute growth rate in the axial direction and the transverse direction and the relative growth rate between them are affected, and the axial direction belongs to layered growth. In the absence of sufficient In the case of zinc oxide nuclei, the growth of each layer may not be complete, and finally a multilayer disk structure is formed.

According to the method of the present invention, the rod-shaped zinc oxide nanocrystal particles have a diameter of 100-150 nm and a length of 800-1000 nm. In order to obtain the above-mentioned rod-shaped zinc oxide nanocrystalline particles, the volume ratio of N, N-dimethylformamide and water can be 6-25: 1, and the contact time can be 1-4 hours; in order to further improve the obtained rod-shaped The homogeneity of zinc oxide nanocrystalline particles, preferably the volume ratio of N,N-dimethylformamide and water is 9-19:1, and the N,N-dimethylformamide, water and hexahydrate The contact time of zinc nitrate is 2-3 hours.

According to the method of the present invention, the truncated hexagonal pyramid-shaped zinc oxide nanocrystal particles have a height of 50-150 nm, a top diameter of 160-240 nm, and a bottom diameter of 280-320 nm. In order to obtain the above-mentioned truncated hexagonal pyramid-shaped zinc oxide nanocrystal particles, the volume ratio of the N,N-dimethylformamide to water is 45-110:1, and the N,N-dimethylformamide, The contact time of water and zinc nitrate hexahydrate is 5-8 hours; In order to further improve the homogeneity of the rod-shaped zinc oxide nanocrystal particles obtained, preferably the volume ratio of N,N-dimethylformamide and water is 49 - 100:1, the contact time of said N,N-dimethylformamide, water and zinc nitrate hexahydrate is 5-7 hours.

According to the method of the present invention, the diameter of the multilayer disk-shaped zinc oxide nano crystal particles is 300-400 nm, the number of layers is 8-20 layers, and the thickness of each layer is 20-40 nm. In order to obtain the above-mentioned multilayer disk-shaped zinc oxide nanocrystal particles, the volume ratio of the N,N-dimethylformamide and water is greater than 500:1, and the N,N-dimethylformamide, water and hexa The contact time of hydrated zinc nitrate is 8-20 hours; In order to further improve the homogeneity of the rod-shaped zinc oxide nanocrystal particles obtained, preferably the volume ratio of N,N-dimethylformamide and water is 600-100000: 1. Preferably, the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 9-15 hours.

According to the method of the present invention, because the control of the ratio of N,N-dimethylformamide and water is necessary, the ratio of N,N-dimethylformamide and water will affect the resulting zinc oxide nanocrystalline particles shape. Therefore, the water contained in the N,N-dimethylformamide used is also calculated in the above ratio. For the convenience of operation, preferably use anhydrous N,N-dimethylformamide, more preferably use anhydrous N,N-dimethylformamide with a water content of 50ppm or less, and further preferably use anhydrous N below 10ppm , N-dimethylformamide. The anhydrous N,N-dimethylformamide can be obtained commercially.

According to the method of the present invention, the method comprises solid-liquid separation of the reacted product, washing and drying the obtained solid to obtain zinc oxide nano crystal particles.

The above solid-liquid separation methods are various methods known in the art. Solids can be obtained, for example, by centrifugation.

The above-mentioned washing method is a method known in the art. For example, after adding ethanol to the obtained solid, perform ultrasonic cleaning, and the number of times of ultrasonic cleaning can be selected according to the actual situation. The present invention preferably ultrasonically cleans twice. The ethanol is preferably absolute ethanol.

The above-mentioned drying method is a method known in the art. For example, the solid separated after washing can be dried at 40-95° C. for 10-24 hours.

In the present invention, zinc oxide nanoparticles with different shapes can be obtained through the ratio of N,N-dimethylformamide and water, and the zinc oxide nanoparticles with different shapes can have different defect concentrations. This is because the solvothermal method is adopted in the present invention. During the synthesis process, N,N-dimethylformamide is easy to deprive the lattice oxygen on the zinc oxide surface, so that oxygen vacancy defects are formed on the surface. The reaction process can use the reaction formula (4) means:

where V _O ·· represents the oxygen vacancy defect on the ZnO surface. At the same time, water is used as the source of lattice oxygen in zinc oxide. When it is extremely lacking, lattice oxygen cannot be replenished in time, and the formation of defects is also indirectly accelerated. From the present invention, water can be used as a regulator of oxygen defect concentration .

The above-mentioned zinc oxide nanoparticles of different shapes can be used as various materials according to their characteristics, for example, rod-shaped zinc oxide nanoparticles with high stability can be obtained without using a surface stabilizer in the method of the present invention, and the Rod-shaped zinc oxide nanoparticles are not wrapped by surface stabilizers, so they can be used as stable photocatalytic materials; truncated hexagonal pyramid-shaped zinc oxide nanoparticles can be prepared as thin films due to the polar side, and can be used as materials for capacitive nanogenerators; Multilayer discoidal zinc oxide nanoparticles have more oxygen defects. The narrow energy level of this defect state can be excited by visible light, and its surface can be modified to inhibit its photocorrosion. It can be used as a wider-band optically active material. .

The present invention is further described through examples below, but the present invention is not limited to the following examples.

The N,N-dimethylformamide in the following examples is purchased from Bailingwei (anhydrous N,N-dimethylformamide, the purity is 99.8%, and the water content is below 50ppm); zinc nitrate hexahydrate and ethanol are purchased from Beijing Chemical Reagent Factory; all the water used was ultrapure water with a resistivity of 18.2 MΩ·cm purified by an electrodeionization machine purchased from Electropure Company of the United States.

In the following examples, the obtained zinc oxide nanoparticles were characterized by SEM using a hitach S-4800 cold field emission scanning electron microscope. The preparation method of the sample used for SEM characterization is to add 3ml of ultrapure water to the zinc oxide nanoparticles (200mg) obtained in the following examples, mix well, and take 10 μl of the mixed solution and drop it on a 5mm×5mm silicon wafer In the incubator at 60°C, it was placed for 1 hour and then taken out for SEM characterization.

In the following examples, Bruker D8 Focus X-ray powder diffractometer is used to carry out XRD characterization of the obtained zinc oxide nanoparticles. The XRD characterization sample preparation method is to drop 2mL of the above-mentioned fully mixed liquid on a glass slide for XRD data characterization.

Example 1

Add 95ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 5ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, and mix well to obtain a mixed solution of reactants . The obtained mixed solution was stirred and reacted at 120°C for 2.5 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain rod-shaped zinc oxide nanoparticle precipitates, and 6 mL of absolute ethanol was added, and after ultrasonic cleaning for 20 minutes, Centrifuge at 13000rpm for 3 minutes, remove the supernatant, add 4mL of absolute ethanol to the obtained precipitate, and ultrasonically clean it again for 20 minutes, then centrifuge at 13000rpm for 3 minutes, remove the supernatant, and put the obtained precipitate into Dry at 85° C. for 15 hours in a thermostat to obtain dried rod-shaped zinc oxide nanoparticles. By scanning electron micrographs, as shown in a in Fig. 1 and b in Fig. 1, it can be seen that the diameter of the rod-shaped zinc oxide nanoparticles is 100-150nm, and the length is 800-1000nm; XPS characterization, the results are shown in Figure 2, Figure 2 is its XPS spectrum O1s peak.

Example 2

Add 98.5ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 1.5ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, mix well to get the reactant mixture. The obtained mixed solution was stirred and reacted at 120°C for 6 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain a truncated hexagonal pyramid-shaped zinc oxide nanoparticle precipitate, which was added to 6 mL of absolute ethanol and ultrasonically cleaned After 20 minutes, centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, add 4 mL of absolute ethanol to the obtained precipitate, and ultrasonically clean it again for 20 minutes, then centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, and The precipitate was put into a thermostat and dried at 85° C. for 15 hours to obtain dried truncated hexagonal pyramid-shaped zinc oxide nanoparticles. By scanning electron micrographs, as shown in c and d in Figure 1, it can be seen that the height of the truncated hexagonal pyramid-shaped zinc oxide nanoparticles is 50-150nm, the diameter of the top surface is 160-240nm, and the diameter of the bottom surface is 280-320nm Carry out XPS characterization to obtain truncated hexagonal pyramid-shaped zinc oxide nanoparticles, the result is shown in Figure 3, and Figure 3 is its XPS energy spectrum O1s peak.

Example 3

Add 100ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, and mix well to obtain a mixed solution of reactants. The obtained mixed solution was stirred and reacted at 120°C for 15 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain a multilayer disk-shaped zinc oxide nanoparticle precipitate, which was added to 6 mL of absolute ethanol and ultrasonically cleaned for 20 Minutes later, centrifuge at 13,000rpm for 3 minutes, remove the supernatant, add 4mL of absolute ethanol to the obtained precipitate, ultrasonically clean it again, and centrifuge at 13,000rpm for 3 minutes, remove the supernatant, and place the obtained precipitate in a constant temperature Dried at 85°C for 15 hours in an oven to obtain dried multilayer discotic zinc oxide nanoparticles, as shown in e and f in Figure 1 through scanning electron micrographs, it can be known that the multilayer discotic zinc oxide nanoparticles The diameter of the particles is 300-400nm, the number of layers is 8-20 layers, and the thickness of each layer is 20nm-40nm; XPS characterization is performed on the obtained multilayer discoidal zinc oxide nanoparticles, and the results are shown in Figure 4, and Figure 4 is its XPS spectrum O1s peak.

Example 4

Add 90ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 10ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, and mix well to obtain a mixed solution of reactants. The obtained mixed solution was stirred and reacted at 120°C for 3 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain rod-shaped zinc oxide nanoparticle precipitates, and 6 mL of absolute ethanol was added, and after ultrasonic cleaning for 20 minutes, Centrifuge at 13000rpm for 3 minutes, remove the supernatant, add 4mL of absolute ethanol to the obtained precipitate, and ultrasonically clean it again for 20 minutes, then centrifuge at 13000rpm for 3 minutes, remove the supernatant, and put the obtained precipitate into Dry at 85° C. for 15 hours in a thermostat to obtain dried rod-shaped zinc oxide nanoparticles. By scanning electron micrographs, it can be seen that the diameter of the rod-shaped zinc oxide nanoparticles is 100-150nm, and the length is 800-1000nm; and its XPS energy spectrum is measured.

Example 5

Add 98ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 2ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, and mix well to obtain a mixed solution of reactants . The obtained mixed solution was stirred and reacted at 125°C for 5 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain truncated hexagonal pyramid-shaped zinc oxide precipitated nanoparticles, which were added to 6 mL of absolute ethanol and ultrasonically cleaned After 20 minutes, centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, add 4 mL of absolute ethanol to the obtained precipitate, and ultrasonically clean it again for 20 minutes, then centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, and The precipitate was put into a thermostat and dried at 85° C. for 15 hours to obtain truncated hexagonal pyramid-shaped zinc oxide nanoparticles after drying. Scanning electron micrographs show that the height of the truncated hexagonal pyramid-shaped zinc oxide nanoparticles is 50-150nm, the diameter of the top surface is 160-240nm, and the diameter of the bottom surface is 280-320nm; and its XPS energy spectrum is measured.

Example 6

Add 100ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 1ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, and mix well to obtain a mixed solution of reactants . The obtained mixed solution was stirred and reacted at 115°C for 7 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain truncated hexagonal pyramid-shaped zinc oxide precipitated nanoparticles, which were added to 6 mL of absolute ethanol and ultrasonically cleaned After 20 minutes, centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, add 4 mL of absolute ethanol to the obtained precipitate, and ultrasonically clean it again for 20 minutes, then centrifuge at 13,000 rpm for 3 minutes, remove the supernatant, and The precipitate was put into a thermostat and dried at 85° C. for 15 hours to obtain dried rod-shaped zinc oxide nanoparticles. Scanning electron micrographs show that the height of the truncated hexagonal pyramid-shaped zinc oxide nanoparticles is 50-150nm, the diameter of the top surface is 160-240nm, and the diameter of the bottom surface is 280-320nm; and its XPS energy spectrum is measured.

Example 7

Add 98.8ml of N,N-dimethylformamide into a 150ml glass bottle container, then add 0.2ml of H ₂ O and 0.75g of Zn(NO ₃ ) ₂ ·6H ₂ O, mix well to get the reactant mixture. The obtained mixed solution was stirred and reacted at 120°C for 9 hours, and after naturally cooling to room temperature, the supernatant in the reaction system was sucked out to obtain multi-layer discoid zinc oxide precipitated nanoparticles, which were added with 6 mL of absolute ethanol and ultrasonically cleaned for 20 Minutes later, centrifuge at 13,000rpm for 3 minutes, remove the supernatant, add 4mL of absolute ethanol to the obtained precipitate, ultrasonically clean it again, and centrifuge at 13,000rpm for 3 minutes, remove the supernatant, and place the obtained precipitate in a constant temperature Dried at 85°C for 15 hours in the oven to obtain dried multilayer discotic zinc oxide nanoparticles. By scanning electron micrographs, it can be seen that the diameter of the multilayer discotic zinc oxide nanoparticles is 300-400nm, and the number of layers is 8-20 layers, the thickness of each layer is 20nm-40nm; and its XPS spectrum is measured.

By X-ray photoelectron spectroscopy (XPS) characterization of the zinc oxide nanoparticles obtained in Examples 1-7, it can be known that the difference in the surface O1s states of zinc oxide nanocrystal particles with different morphologies is more significant, and the analysis by Gaussian fitting The O1s state of zinc oxide can be divided into three peaks, in which Oa can be classified as surface lattice oxygen, Ob can be classified as surface oxygen defects, and Oc can be classified as surface-adsorbed oxygen-containing species such as: OH group, carbonic acid Root negative ions and oxygen negative ions, etc. From the X-ray photoelectron spectroscopy (XPS) characterization of the zinc oxide nanoparticles obtained in Examples 1-7, it can be clearly observed that the multilayer disk zinc oxide contains more oxygen defects, followed by truncated hexagonal pyramids, and rods are the least . It can be seen that the method of the present invention can not only control the shape of the prepared zinc oxide nanoparticles well, but also effectively control the defect concentration of zinc oxide nanoparticles with different shapes, so as to meet the needs of various materials.

Claims (6)

1. A method for controlling the morphology of zinc oxide nanoparticles, the method comprising at a temperature of 110-140 ° C, N, N-dimethylformamide, water and zinc nitrate hexahydrate contact, it is characterized in that, by Control the ratio of N,N-dimethylformamide and water and the contact time of N,N-dimethylformamide, water and zinc nitrate hexahydrate to obtain zinc oxide nanoparticles with different shapes; Wherein, the zinc oxide nanoparticles are rod-shaped, and the rod-shaped zinc oxide nanoparticles have a diameter of 100-150 nm and a length of 800-1000 nm; the volume ratio of N,N-dimethylformamide to water is 6-25:1 , the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 1-4 hours; Alternatively, the zinc oxide nanoparticles are in the shape of a truncated hexagonal pyramid, the height of the truncated hexagonal pyramidal zinc oxide nanoparticles is 50-150nm, the diameter of the top surface is 160-240nm, and the diameter of the bottom surface is 280-320nm; N, N -The volume ratio of dimethylformamide and water is 45-110:1, and the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 5-8 hours; Alternatively, the zinc oxide nanoparticles are multilayer disk-shaped, the diameter of the multilayer disk-shaped zinc oxide nanoparticles is 300-400nm, the number of layers is 8-20 layers, and the thickness of each layer is 20-40nm. The N , The volume ratio of N-dimethylformamide to water is greater than 500:1, and the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 8-20 hours. 2. The method according to claim 1, wherein the temperature of the contact is 115-125°C, and the mass ratio of the zinc nitrate hexahydrate to the total volume ratio of N,N-dimethylformamide and water is 5 -10: 1g/L. 3. The method according to claim 2, wherein the mass of the zinc nitrate hexahydrate to the total volume ratio of N,N-dimethylformamide and water is 7-8:1g/L. 4. The method according to claim 1, wherein the zinc oxide nanoparticles are rod-shaped, the diameter of the rod-shaped zinc oxide nanoparticles is 100-150nm, and the length is 800-1000nm, and the N,N-dimethyl The volume ratio of formamide to water is 9-19:1, and the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 2-3 hours. 5. The method according to claim 1, wherein the zinc oxide nanoparticles are truncated hexagonal pyramids, the height of the truncated hexagonal pyramidal zinc oxide nanoparticles is 50-150nm, and the diameter of the top surface is 160-240nm , the diameter of the bottom surface is 280-320nm, the volume ratio of the N,N-dimethylformamide and water is 49-100:1, the N,N-dimethylformamide, water and zinc nitrate hexahydrate The contact time is 5-7 hours. 6. The method according to claim 1, wherein the zinc oxide nanoparticles are multilayer disks, the diameter of the multilayer disk zinc oxide nanoparticles is 300-400nm, and the number of layers is 8-20 layers, each The thickness of the layer is 20-40 nm, and the contact time of the N,N-dimethylformamide, water and zinc nitrate hexahydrate is 9-15 hours.

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