Preparation method and application of nano powder

Abstract

The invention provides a method for preparing nano powder. The preparation method of the nano powder comprises the following steps: 1, directly ablating the surface of an inorganic target material by adopting laser to ablate nano particles from the surface of the target material; 2, collecting the nano particles by the following two schemes: 1) adopting a barrel-like container to cover the sputtering position of the nano particles; (2) aligning a suction head of a dust collector to the ablation area, and meanwhile, blowing the nanoparticles to the suction head by a fan; 3, extracting the particles according to the two schemes: taking down the nano powder from the inner surface of the container; the nano-particles are oscillated from a dust isolation bag and a collection bag of a dust collector in an ultrasonic mode, and the nano-particles are further extracted in a graded mode through a centrifugal machine to obtain the nano-powder. The nano powder has photocatalytic activity and can be activated under a normal sunshine condition; and the material can also be used for other catalysts, biomedicine, pollution repair and electrode materials of batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanopowder preparation, and prepares nanopowders by the method of rapid laser ablation. Specifically, it relates to a method for preparing nanopowders and its applications. Background Art

[0002] Nanopowders have extensive applications in aspects such as catalysts, biomedicine, pollution remediation, and electrode materials for batteries.

[0003] Currently, there is a significant phenomenon of "bad money driving out good money" in the nanopowder market. Taking Taobao as an example, metal nanopowders with a size of 20 nanometers are sold at extremely low prices (less than 10 yuan per gram) and are only presented in a simple bottled form. This phenomenon ignores the key technical challenges faced by nanopowders during storage and transportation, such as the agglomeration of nanoparticles and the risk of combustion. If pure metal nanoparticles are in the bottle, they will spontaneously agglomerate and grow to reduce their surface energy.

[0004] In contrast, the price of passivated nanopowders, such as colloidal solutions or metal nanoparticles passivated with core-shell structures, is significantly higher than that of untreated products. For example, the price of a colloidal solution prepared from 1 gram of nanopowder can reach several hundred to thousands of yuan, and the price of 100-nanometer core-shell structure passivated metal nanoparticles starts from 500 yuan per gram. These stabilized nanomaterials are relatively scarce and expensive in the market due to their high technical threshold and cost.

[0005] The present invention produces nanopowders by directly laser ablating inorganic targets, which is fast, simple, and efficient, and is expected to significantly reduce the cost of nanopowder preparation and achieve large-scale production. Summary of the Invention

[0006] The present invention provides a method for preparing nanopowders and its applications. By changing the target composition, laser parameters, and atmosphere regulation, the formed nanopowders are obtained, thereby achieving the purpose of preparing nanopowders.

[0007] To achieve the above-mentioned invention purpose, the technical solution of the present invention is as follows:

[0008] The present invention provides a method for preparing nanopowders, including the following steps:

[0009] (1) Using laser to directly ablate the surface of an inorganic target to ablate nanoparticles from the target surface;

[0010] (2) Collecting the nanoparticles includes the following two schemes: 1) Using a bucket-shaped container to cover the position where the nanoparticles are sputtered out; 2) Aligning the suction head of a vacuum cleaner with the ablation area, and at the same time equipping a fan to blow the nanoparticles towards the suction head;

[0011] (3) Extract particles for the above two schemes: Remove the nano powder from the inner surface of the container; Oscillate the nano particles from the dust bag and collection bag of the vacuum cleaner by ultrasonic waves, and further extract the nano powder by a centrifuge.

[0012] Further, the inorganic material target includes at least one of silver, niobium, manganese, nickel, molybdenum, iron, tungsten, titanium, vanadium, copper, aluminum, magnesium, zinc, bismuth, zirconium, silicon, carbon, etc.; It also includes alloys, compounds, and composite materials of the above elements.

[0013] The typical process parameters of laser ablation are as follows: Use a 2000-watt laser cleaning machine to focus on a piece of iron, with a line width of 30 - 600 mm and a laser scanning speed of 10 mm / s - 10 m / s.

[0014] In the present invention, the process parameters of different devices are different and can be selected according to actual needs.

[0015] Further, reaction gases and protective gases such as oxygen, air, nitrogen, and argon can be introduced during the laser ablation process in step (1).

[0016] In step (2), if a bucket-shaped container is used for collection, a fan can be used to blow part of the escaped powder back into the bucket during laser ablation.

[0017] In step (3), a filter screen can be placed in the centrifuge bottle or centrifuge tube to separate large particles and small particles.

[0018] Further, the prepared nano powder can be used in aspects such as catalysts, biomedicine, pollution remediation, and electrode materials for batteries.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0020] 1. The method of directly laser ablating inorganic targets is simple and efficient. It can be produced in air, and the obtained nano powder has been passivated and is relatively stable.

[0021] 2. The entire preparation method has low cost and can be completed using industrialized stable and mature equipment, having the advantage of scalable production. Description of the Drawings

[0022] Figure 1 It is a real scene photo of the nano powder obtained in Example 1.

[0023] Figure 2 It is a transmission electron microscope photo of the nano powder obtained in Example 1.

[0024] Figure 3 It is a transmission electron microscope photo of the nano powder obtained in Example 2.

[0025] Figure 4 is a picture of the EDS mapping of the nanopowder obtained in Example 2.

[0026] Figure 5 is the XRD photograph of the nanopowder obtained in Example 2.

[0027] Figure 6 is the photograph of the decomposition of methyl orange solution by the nanopowder obtained in Example 2 under outdoor natural light.

[0028] Figure 7 is the transmission electron microscope photograph of the nanopowder obtained in Example 3.

[0029] Figure 8 is the transmission electron microscope photograph of the nanopowder obtained in Example 4.

[0030] Figure 9 is the transmission electron microscope photograph of the nanopowder obtained in Example 5.

[0031] Figure 10 is the transmission electron microscope photograph of the nanopowder obtained in Example 6. Detailed implementation manners

[0032] The following implementation manners better illustrate the content of the present invention. However, the present invention is not limited to the following examples.

[0033] Example 1

[0034] The specific steps for preparing the titanium-based nanopowder are as follows:

[0035] (1) Focus a 2000-watt laser cleaning machine on the titanium plate in the collection bucket, with a line width of 50 mm - 300 mm, a scanning speed of 10 mm / s - 10 m / s, and scan for 10 min. Note that the default ablation atmosphere is in air without special instructions.

[0036] (2) Use a brush and a scraper to remove the nanopowder deposited on the inner surface of the collection bucket and pour it into the collection tube.

[0037] Figure 1 shows the actual scene photograph of the obtained nanopowder. Figure 2 shows the transmission electron microscope photograph of these nanoparticles. It can be seen that most of the nanoparticles are less than 20 nm.

[0038] Example 2

[0039] The specific steps for preparing the copper-zinc-based nanopowder are as follows:

[0040] (1) Focus a 2000-watt laser cleaning machine on the copper plate, with a line width of 50 mm - 300 mm, a scanning speed of 10 mm / s - 10 m / s, and scan for 30 min. At the same time, use a vacuum cleaner to suck away the ablated nanopowder.

[0041] (2) Place the vacuum cleaner dust bag in alcohol and ultrasonically vibrate for 15 minutes.

[0042] (3) Focus a 2000-watt laser cleaning machine onto the zinc plate, with a line width of 50 mm to 300 mm, a scanning speed of 10 mm / s to 10 m / s, and a scanning time of 30 min. At the same time, use a vacuum cleaner to remove the ablated nanopowder.

[0043] (4) Place the vacuum cleaner dust bag into the alcohol prepared in step (2) and ultrasonically vibrate for 15 minutes.

[0044] (5) Pour the shaken liquid into a centrifuge bottle / centrifuge tube at a centrifugal speed of 4000 rpm; pour out the supernatant, and the copper-zinc-based nanopowder remains in the centrifuge bottle.

[0045] Figure 3 The transmission electron microscope photos of these powders are shown. It can be seen that most of the nanoparticles are smaller than 20nm. Figure 4 shows its EDS photos, which shows that the oxygen content decreases towards the center, while the metal content increases, indicating that the nanoparticles are core-shell structures, with the outer shell being oxide and the inner core being metal. Figure 5 This is the XRD spectrum of copper-zinc-based nanopowder. It can be seen that the main peak is metal peak, the oxide peak is short and wide, and there is no copper oxide peak. It may be amorphous or the amount is very small, which is consistent with the transmission electron microscopy results, indicating that it is a thin oxide shell wrapped around the metal core. Figure 6 The process of the solution changing from orange to colorless and transparent after the nanopowder was placed in a methyl orange solution and left outdoors for 4 days was demonstrated. The excellent catalytic performance of the nanopowder was demonstrated.

[0046] Example 3

[0047] The specific steps for preparing tungsten-based nanopowder are as follows:

[0048] (1) Focus a 2000W laser cleaning machine onto a tungsten plate with a line width of 50mm-300mm, a scanning speed of 10mm / s-10m / s, and scan for 30min. At the same time, use a vacuum cleaner to remove the ablated nanopowder.

[0049] (2) Place the dust bag of the vacuum cleaner in alcohol and ultrasonically vibrate for 15 minutes. Pour the vibrated solution into a centrifuge bottle / centrifuge tube. The centrifugal speed is 6000 rpm; pour out the supernatant, and the nanopowder remains in the centrifuge bottle.

[0050] Figure 6 The transmission electron microscope photo of tungsten-based nanopowders is shown. It can be seen that most of the nanoparticles are smaller than 20nm.

[0051] Example 4

[0052] The specific steps for preparing iron-based nanopowder are as follows:

[0053] (1) Focus a 2000-watt laser cleaning machine on an iron plate, with a line width of 50 mm - 300 mm, a scanning speed of 10 mm / s - 10 m / s, and scan for 30 minutes. At the same time, use a vacuum cleaner to suck away the ablated nano-powder.

[0054] (2) Place the dust bag of the vacuum cleaner in alcohol and ultrasonically oscillate for 15 minutes. Pour the oscillating liquid into a centrifuge bottle / centrifuge tube. The centrifugation speed is 6000 rpm; pour out the supernatant, and the centrifuge bottle will be left with nano-powder.

[0055] Figure 7 The transmission electron microscope photo of the iron-based nano-powder is shown. It can be seen that most of the nano-particles are less than 20 nm.

[0056] Example 5

[0057] The specific steps for preparing stainless steel-based nano-powder are as follows:

[0058] (1) Focus a 2000-watt laser cleaning machine on a stainless steel plate, with a line width of 50 mm - 300 mm, a scanning speed of 10 mm / s - 10 m / s, and scan for 30 minutes. At the same time, use a vacuum cleaner to suck away the ablated nano-powder.

[0059] (2) Place the dust bag of the vacuum cleaner in alcohol and ultrasonically oscillate for 15 minutes. Pour the oscillating liquid into a centrifuge bottle / centrifuge tube. The centrifugation speed is 6000 rpm; pour out the supernatant, and the centrifuge bottle will be left with nano-powder.

[0060] Figure 8 The transmission electron microscope photo of the stainless steel-based nano-powder is shown. It can be seen that most of the nano-particles are less than 20 nm.

[0061] Example 6

[0062] The specific steps for preparing brass-based nano-powder are as follows:

[0063] (1) Focus a 2000-watt laser cleaning machine on a brass plate, with a line width of 50 mm - 300 mm, a scanning speed of 10 mm / s - 10 m / s, and scan for 30 minutes. At the same time, use a vacuum cleaner to suck away the ablated nano-powder.

[0064] (2) Place the dust bag of the vacuum cleaner in alcohol and ultrasonically oscillate for 15 minutes. Pour the oscillating liquid into a centrifuge bottle / centrifuge tube. The centrifugation speed is 6000 rpm; pour out the supernatant, and the centrifuge bottle will be left with nano-powder.

[0065] Figure 9 The transmission electron microscope photo of the brass-based nano-powder is shown. It can be seen that most of the nano-particles are less than 20 nm.

[0066] As shown in the above embodiments, the properties of the nanopowder can be adjusted by replacing the inorganic target and laser scanning parameters, and it can be widely used in catalysts, biomedicine, pollution remediation, and electrode materials for batteries.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions required to be protected by the present invention.

Claims

1. A method for preparing a rapid nano powder, characterized in that: The following steps are involved: (1) Directly ablate the surface of an inorganic target material using laser to ablate nanoparticles from the target surface; (2) Collecting nanoparticles includes the following two schemes: 1) using a barrel-shaped container to encompass the location where the nanoparticles are sputtered; 2) using a vacuum cleaner nozzle to aim at the ablation area and equipping it with a fan to blow the nanoparticles toward the nozzle. (3) Removing the nanopowder from the inner surface of the container; using ultrasonic wave to vibrate the micro-nano particles from the dust bag / collection bag of the vacuum cleaner, and further using a centrifuge to extract the nanopowder.

2. The method for preparing nanopowder according to claim 1, characterized in that: The laser includes continuous laser and pulse laser.

3. The method for preparing nanopowder according to claim 1, characterized in that: The inorganic target material includes at least one of silver, niobium, manganese, nickel, molybdenum, iron, tungsten, titanium, vanadium, copper, aluminum, magnesium, zinc, bismuth, zirconium, silicon, carbon, etc.; and also includes alloys, compounds, and composite materials of the above elements.

4. The method for preparing nanopowder according to claim 1, characterized in that: In step (1), a reaction gas or a protective gas such as oxygen, air, nitrogen or argon may be introduced.

5. The nanopowder according to claim 1 can be used in catalysts, biomedicine, pollution remediation, and battery electrode materials.

6. The nanopowder prepared by the preparation method according to any one of claims 1 to 5 and its application.

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