CN113788479A - Preparation method of graphite-based quantum dots - Google Patents
Preparation method of graphite-based quantum dots Download PDFInfo
- Publication number
- CN113788479A CN113788479A CN202111267837.9A CN202111267837A CN113788479A CN 113788479 A CN113788479 A CN 113788479A CN 202111267837 A CN202111267837 A CN 202111267837A CN 113788479 A CN113788479 A CN 113788479A
- Authority
- CN
- China
- Prior art keywords
- graphite
- based quantum
- preparing
- quantum dots
- quantum dot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 71
- 239000010439 graphite Substances 0.000 title claims abstract description 71
- 239000002096 quantum dot Substances 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 18
- 239000002253 acid Substances 0.000 claims abstract description 13
- 238000000498 ball milling Methods 0.000 claims abstract description 12
- 239000007788 liquid Substances 0.000 claims abstract description 11
- 238000010992 reflux Methods 0.000 claims abstract description 9
- 239000006185 dispersion Substances 0.000 claims abstract description 8
- 239000008367 deionised water Substances 0.000 claims abstract description 7
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 7
- 238000010907 mechanical stirring Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000001035 drying Methods 0.000 claims abstract description 6
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 4
- 239000000919 ceramic Substances 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims abstract description 3
- 238000000502 dialysis Methods 0.000 claims description 10
- 229910017604 nitric acid Inorganic materials 0.000 claims description 6
- 238000000746 purification Methods 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 5
- 238000005119 centrifugation Methods 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 2
- 238000009777 vacuum freeze-drying Methods 0.000 claims description 2
- 239000002243 precursor Substances 0.000 abstract description 9
- 238000009826 distribution Methods 0.000 abstract description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 9
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011031 large-scale manufacturing process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910021382 natural graphite Inorganic materials 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000001241 arc-discharge method Methods 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 239000002608 ionic liquid Substances 0.000 description 1
- 238000000608 laser ablation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004729 solvothermal method Methods 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
Abstract
The invention relates to a preparation method for preparing graphite-based quantum dots, which is characterized by comprising the following steps: (1) placing natural fine-flake graphite into a ceramic crucible, placing the crucible into a muffle furnace, and heating for 1-3 h at 900-1200 ℃ to prepare graphite with high fixed carbon content; (2) ball-milling the graphite obtained in the step (1) for 2-4 h at 3000-6000 rpm/min to obtain graphite powder; (3) placing graphite powder into mixed acid, controlling the mass-volume ratio of the graphite powder to the mixed acid to be 1: 10-50, and refluxing the mixture for 24-48 hours under the mechanical stirring condition, wherein the refluxing temperature is 60-100 ℃; (4) and (4) centrifuging the black dispersion liquid obtained in the step (3), dialyzing the upper layer liquid in deionized water for 5-7 days, drying the dialyzate, and removing the deionized water to obtain the target product graphite-based quantum dots. The invention has the advantages that: the natural fine flake graphite is used as a precursor to prepare the graphite-based quantum dots, the price is low, the resources are rich, the size distribution of the prepared graphite-based quantum dots is uniform, the process is simple, and the operation is easy.
Description
Technical Field
The invention belongs to the technical field of nano material preparation, and particularly relates to a preparation method of graphite-based quantum dots.
Background
The preparation strategies of the carbon quantum dots can be roughly divided into a Top-down (Top-down) strategy and a Bottom-up (Bottom-up) strategy. A physical or chemical method is adopted to strip a precursor with larger size into carbon quantum dots with smaller size from top to bottom, the specific method comprises an arc discharge method, a laser ablation method, an electrochemical synthesis method and the like, and the corresponding precursor comprises graphite, carbon nano tubes, carbon fibers, graphite rods, activated carbon and the like. The strategy of preparation from bottom to top is just opposite to the strategy from top to bottom, the strategy from bottom to top utilizes molecular or ionic precursors to prepare the carbon quantum dots, the commonly used precursors comprise saccharides, amines, alcohols, organic matters, ionic liquid and the like, and the specific synthetic methods comprise a chemical oxidation method, a pyrolysis method, a hydrothermal/solvothermal method, a microwave synthesis method, a template method and the like. From the aspect of preparation raw materials, along with the continuous widening of the types of precursors, the materials are more evolved to be low in price, green and environment-friendly; from the viewpoint of the preparation process, researchers have produced carbon quantum dots with controllable sizes by optimizing the preparation process.
Although the carbon quantum dots are simple in preparation process, rich in raw materials and various in preparation method, the defects of low yield, high cost, complex process, poor product consistency, incapability of large-scale production and the like generally exist, and the practical application of the carbon quantum dots is greatly limited. Therefore, the development of a novel carbon quantum dot which can be produced in large scale and has high commercial value is necessary and necessary, and related researches have great theoretical and practical significance. As is well known, natural fine flake graphite is low in price and rich in resources, and if the natural fine flake graphite is used for producing and preparing graphite-based quantum dots, the production cost of the carbon quantum dots can be greatly reduced, and the natural fine flake graphite has price advantages which cannot be compared with the traditional carbon quantum dots. At present, the research related to the preparation of the graphite-based quantum dots by adopting natural graphite is not reported.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a preparation method for preparing graphite-based quantum dots.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method for preparing graphite-based quantum dots is characterized by comprising the following steps:
(1) selecting natural fine-flake graphite as a raw material, placing the natural fine-flake graphite in a ceramic crucible, then placing the crucible in a muffle furnace for high-temperature purification, and heating at 900-1200 ℃ for 1-3 h to prepare graphite with the fixed carbon content of 90-95%;
(2) ball-milling the graphite obtained in the step (1) by adopting a ball milling method, controlling the rotating speed of a ball mill to be 3000-6000 rpm/min, and ball-milling for 2-4 h to obtain graphite powder;
(3) placing graphite powder in mixed acid (H)2SO4And HNO3) In the method, the mass-to-volume ratio of the graphite powder to the mixed acid is controlled to be 1: 10-50 (g/ml), then the mixture is refluxed for 24-48 hours under mechanical stirring (200-400 rpm/min), and the reflux temperature is controlled to be 60-100 ℃;
(4) and (4) performing centrifugal separation on the black dispersion liquid obtained in the step (3), removing impurities at the bottom of a centrifugal tube, putting the upper layer liquid into deionized water for dialysis for 5-7 days to obtain dialysate, drying the dialysate, and removing the deionized water to obtain the target product graphite-based quantum dots.
Further, the graphite-based quantum dots have a layered structure of graphite.
Further, the natural fine flake graphite is produced from Panzhihua city kernel and district Zhongbaoxian.
Further, the particle size of the natural fine flake graphite is less than 100 meshes.
Further, H in the mixed acid2SO4And HNO3In a volume ratio of 1: a0.5～4。
Further, the centrifugation speed is 2000-6000 rpm/min, and the centrifugation time is 20-30 min.
Furthermore, the dialysis adopts a dialysis bag with the intercepted molecular weight of 1000-4000.
Further, the drying mode is vacuum freeze drying, and the drying time is 24-48 h.
The invention has the beneficial effects that:
the invention adopts natural fine flake graphite as a precursor to prepare the graphite-based quantum dots, the natural fine flake graphite has low price and rich resources, the cost for producing and preparing the graphite-based quantum dots is low, the size distribution is uniform, and the preparation process is simple, easy to operate and beneficial to large-scale production.
Drawings
Fig. 1 is a process for preparing the graphite-based quantum dot of example 1;
fig. 2 TEM image of graphite-based quantum dots prepared in example 1;
fig. 3 XRD pattern of graphite-based quantum dots prepared in example 1.
Example 1
The invention is further illustrated with reference to fig. 1:
a preparation method of graphite-based quantum dots comprises the following specific implementation steps:
(1) 20g of Panzhihua city kernel and natural fine flake graphite (80 meshes) produced in Zhongzhuan county are weighed and placed in a ceramic crucible; then, the crucible is placed in a muffle furnace for high-temperature purification, and is calcined for 2 hours at the temperature of 1000 ℃ to prepare graphite with the fixed carbon content of 92%;
(2) transferring the graphite prepared in the step (1) into a ball mill, setting the rotating speed of the ball mill to be 5000 rpm/min, and carrying out ball milling for 4 hours;
(3) placing the graphite powder subjected to ball milling in the step (2) in 800 ml of mixed acid (H)2SO4And HNO3Volume ratio of the graphite powder to the mixed acid is 1: 40 (g/ml); then refluxing the mixture for 36 h under mechanical stirring, wherein the refluxing temperature is controlled at 80 ℃; wherein the mechanical stirring speed is 200 rpm/min;
(4) centrifuging the black dispersion liquid obtained in the step (3), wherein the speed of a centrifuge is 5000 rpm/min, and centrifuging to remove large-particle impurities in the black dispersion liquid to obtain black upper-layer dispersion liquid;
(5) transferring the black dispersion liquid in the step (4) into a dialysis bag, dialyzing in deionized water for 7 days, and removing H in the black dispersion liquid2SO4And HNO3Obtaining black dialysate; wherein the cut-off molecular weight of the dialysis bag is 1000 Da;
(6) and (5) placing the black dialysate in the step (5) into a freeze dryer, and drying for 48 hours to obtain the target product graphite-based quantum dots.
The mass of the graphite-based quantum dots prepared above was about 7.0 g, and the yield was about 35%.
As shown in FIG. 1, the graphite-based quantum dots prepared above are spheroidal, have a uniform size distribution, and have a small particle diameter of about 5.4 nm.
As shown in fig. 2, the obtained graphite-based quantum dot is substantially identical to the XRD of graphite, which indicates that the prepared graphite-based quantum dot and graphite have similar crystal structures.
Examples 2 to 4
Natural fine flake graphite is selected as a precursor, and parameters such as precursor quality, graphite purification temperature and time, ball milling speed and time, graphite and mixed acid ratio and the like are respectively regulated and controlled in examples 2 to 4, so that the graphite-based quantum dots are prepared. The corresponding experimental parameters and experimental results are shown in table 1:
table 1 examples 2-4 experimental parameters and experimental results
| Example 2 | Example 3 | Example 4 | Example 4 | Example 4 | Example 4 | |
| Natural graphite quality (g) | 20 | 20 | 10 | 20 | 30 | 40 |
| Purification temperature (. degree.C.) | 1000 | 1000 | 900 | 1100 | 1200 | 1000 |
| Purification time (h) | 1 | 3 | 2 | 1 | 2 | 3 |
| Ball milling speed (rpm/min) | 3000 | 4000 | 5000 | 6000 | 5000 | 5000 |
| Ball milling time (h) | 1 | 2 | 3 | 4 | 4 | 4 |
| Volume of mixed acid (ml) | 1000 | 800 | 300 | 400 | 900 | 1600 |
| Volume ratio of mixed acid (H)2SO4/HNO3） | 1/0.5 | 1/1 | 1/2 | 1/3 | 1/4 | 1/5 |
| Mechanical stirring speed (rpm/min) | 200 | 200 | 300 | 300 | 400 | 400 |
| Reflux time (h) | 24 | 24 | 48 | 36 | 36 | 36 |
| Reflux temperature (. degree.C.) | 60 | 60 | 60 | 70 | 90 | 100 |
| Centrifuge Rate (rpm/min) | 5000 | 5000 | 2000 | 3000 | 4000 | 6000 |
| Centrifuge time (min) | 20 | 20 | 25 | 25 | 30 | 30 |
| Cut-off molecular weight of dialysis bag (Da) | 2000 | 3000 | 4000 | 1000 | 1000 | 1000 |
| Dialysis time (d) | 5 | 5 | 6 | 6 | 7 | 7 |
| Time of lyophilization (h) | 48 | 36 | 24 | 24 | 36 | 48 |
| Average particle size (nm) of graphite-based quantum dots | 9.7 | 9.3 | 8.5 | 7.1 | 5.9 | 4.0 |
| Graphite-based quantum dot yield (%) | 21 | 24 | 31 | 26 | 32 | 40 |
Claims (9)
1. A preparation method for preparing graphite-based quantum dots is characterized by comprising the following steps:
(1) selecting natural fine-flake graphite as a raw material, placing the natural fine-flake graphite in a ceramic crucible, then placing the crucible in a muffle furnace for high-temperature purification, and heating at 900-1200 ℃ for 1-3 h to prepare graphite with the fixed carbon content of 90-95%;
(2) ball-milling the graphite obtained in the step (1) by adopting a ball milling method, controlling the rotating speed of a ball mill to be 3000-6000 rpm/min, and ball-milling for 2-4 h to obtain graphite powder;
(3) placing graphite powder in mixed acid, controlling the mass-to-volume ratio of the graphite powder to the mixed acid to be 1: 10-50, and refluxing the mixture for 24-48 hours under mechanical stirring, wherein the reflux temperature is controlled to be 60-100 ℃;
(4) and (4) performing centrifugal separation on the black dispersion liquid obtained in the step (3), removing impurities at the bottom of a centrifugal tube, putting the upper layer liquid into deionized water for dialysis for 5-7 days to obtain dialysate, drying the dialysate, and removing the deionized water to obtain the target product graphite-based quantum dots.
2. The method of claim 1, wherein the step of preparing the graphite-based quantum dot comprises: the graphite-based quantum dots have a graphite layered structure.
3. The method of claim 1, wherein the step of preparing the graphite-based quantum dot comprises: the natural fine flake graphite is produced from Panzhihua city kernel and Zhongbaxiang in the region.
4. The method of claim 1, wherein the step of preparing the graphite-based quantum dot comprises: the particle size of the natural fine flake graphite is less than 100 meshes.
5. The method of claim 1, wherein the step of preparing the graphite-based quantum dot comprises: h in the mixed acid2SO4And HNO3The volume ratio of (A) to (B) is 1: 0.5-4.
6. The method of claim 1, wherein the step of preparing the graphite-based quantum dot comprises: and (3) the mechanical stirring speed in the step (3) is 200-400 rpm/min.
7. The method for preparing a graphite-based quantum dot according to any one of claims 1 to 6, wherein: the centrifugation speed of the step (4) is 2000-6000 rpm/min, and the centrifugation time is 20-30 min.
8. The method for preparing a graphite-based quantum dot according to any one of claims 1 to 6, wherein: and (4) adopting a dialysis bag with the intercepted molecular weight of 1000-4000 for dialysis.
9. The method for preparing a graphite-based quantum dot according to any one of claims 1 to 6, wherein: and (4) performing vacuum freeze drying for 24-48 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111267837.9A CN113788479A (en) | 2021-10-29 | 2021-10-29 | Preparation method of graphite-based quantum dots |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111267837.9A CN113788479A (en) | 2021-10-29 | 2021-10-29 | Preparation method of graphite-based quantum dots |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113788479A true CN113788479A (en) | 2021-12-14 |
Family
ID=78878337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111267837.9A Pending CN113788479A (en) | 2021-10-29 | 2021-10-29 | Preparation method of graphite-based quantum dots |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113788479A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102849724A (en) * | 2012-10-12 | 2013-01-02 | 上海交通大学 | Preparation method of water-soluble carbon quantum dots |
| CN103265020A (en) * | 2013-05-27 | 2013-08-28 | 中国科学院上海微***与信息技术研究所 | Method for preparing graphene quantum dot powder on large scale |
| CN105502340A (en) * | 2015-12-30 | 2016-04-20 | 哈尔滨工业大学 | Preparation method of fluorescent carbon dots |
| CN105883734A (en) * | 2016-04-08 | 2016-08-24 | 山东大学 | Graphite phase carbon nitride quantum dot and preparation method thereof |
| US20180086976A1 (en) * | 2015-03-31 | 2018-03-29 | South China University Of Technology | Porous graphene, graphene quantum dot, and green manufacturing method therefor |
| CN108467028A (en) * | 2018-04-26 | 2018-08-31 | 上海大学 | The preparation method and application of intelligent graphene quantum dot cluster |
| CN109052381A (en) * | 2018-09-30 | 2018-12-21 | 西安理工大学 | A kind of method that microexplosion method prepares graphene quantum dot |
-
2021
- 2021-10-29 CN CN202111267837.9A patent/CN113788479A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102849724A (en) * | 2012-10-12 | 2013-01-02 | 上海交通大学 | Preparation method of water-soluble carbon quantum dots |
| CN103265020A (en) * | 2013-05-27 | 2013-08-28 | 中国科学院上海微***与信息技术研究所 | Method for preparing graphene quantum dot powder on large scale |
| US20180086976A1 (en) * | 2015-03-31 | 2018-03-29 | South China University Of Technology | Porous graphene, graphene quantum dot, and green manufacturing method therefor |
| CN105502340A (en) * | 2015-12-30 | 2016-04-20 | 哈尔滨工业大学 | Preparation method of fluorescent carbon dots |
| CN105883734A (en) * | 2016-04-08 | 2016-08-24 | 山东大学 | Graphite phase carbon nitride quantum dot and preparation method thereof |
| CN108467028A (en) * | 2018-04-26 | 2018-08-31 | 上海大学 | The preparation method and application of intelligent graphene quantum dot cluster |
| CN109052381A (en) * | 2018-09-30 | 2018-12-21 | 西安理工大学 | A kind of method that microexplosion method prepares graphene quantum dot |
Non-Patent Citations (1)
| Title |
|---|
| 赵志凤等: "《炭材料工艺基础》", 30 November 2017, 哈尔滨工业大学出版社 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108975310B (en) | Preparation method of pressure-assisted size-controllable hydrothermal carbon sphere and prepared hydrothermal carbon sphere | |
| CN106629661A (en) | Process for preparing carbon nanospheres from bagasse | |
| CN103864137B (en) | Flower shape zinc oxide nano material and preparation method thereof | |
| CN105600779A (en) | Method for preparing self-assembly all-carbon three-dimensional graphene from papermaking black liquid | |
| CN110117006A (en) | A kind of method that high-efficiency environment friendly prepares grapheme material | |
| CN104289244A (en) | Preparation method for porous g-C3N4/AgBr nanometer composite material | |
| CN105542761A (en) | Method for preparing fluorescence carbon dots taking rice bran as carbon source | |
| CN107556329A (en) | A kind of porous metals organic framework materials and preparation method thereof | |
| CN110655056A (en) | Preparation method of porous nano silicon-carbon composite material | |
| CN114249326A (en) | Method for preparing sub-nano silicon-carbon composite material by liquid phase method | |
| CN113788479A (en) | Preparation method of graphite-based quantum dots | |
| CN109675568B (en) | In-situ preparation method and application of Ni/NiO composite material | |
| CN111595918A (en) | Octahedron Cu-Cu2Preparation method of O composite material | |
| CN114835122B (en) | Method for preparing silicon carbide aerogel powder from coal gangue | |
| CN108940366B (en) | Preparation method of pore-adjustable Fe-based metal organic framework-phosphotungstic acid | |
| CN111807380B (en) | Method for preparing three-dimensional multilevel structure basic nickel silicate catalyst by one pot | |
| CN111392715A (en) | Preparation method of three-dimensional graphene material | |
| CN113697794A (en) | Method for preparing dendritic superfine hydrothermal carbon by slow temperature control method, prepared hydrothermal carbon adsorption ball and application | |
| CN111439745B (en) | Preparation method of single-layer or few-layer biomass graphene | |
| CN110697725B (en) | Preparation method of lithium disilicate whisker | |
| CN113666370A (en) | Method for preparing capacitance carbon material by secondary microbial fermentation and activation of vinasse | |
| CN113501529A (en) | Preparation method of sodium silicate for tire reinforcing agent | |
| CN111892034A (en) | Mass production method of long-range ordered mesoporous carbon/mesoporous silicon material with ultrahigh specific surface area | |
| CN107777682A (en) | The method that graphene nanometer sheet is prepared based on micro crystal graphite wet grinding | |
| CN104528820A (en) | Preparation method of multilevel structural titanium dioxide nano flower string |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211214 |
|
| RJ01 | Rejection of invention patent application after publication |