WO2018056801A1 - Preparation of carbon quantum dots - Google Patents

Preparation of carbon quantum dots Download PDF

Info

Publication number
WO2018056801A1
WO2018056801A1 PCT/MY2017/050055 MY2017050055W WO2018056801A1 WO 2018056801 A1 WO2018056801 A1 WO 2018056801A1 MY 2017050055 W MY2017050055 W MY 2017050055W WO 2018056801 A1 WO2018056801 A1 WO 2018056801A1
Authority
WO
WIPO (PCT)
Prior art keywords
cqd
carbonaceous particles
dispersion
alcohol
quantum dots
Prior art date
Application number
PCT/MY2017/050055
Other languages
French (fr)
Inventor
Suraya ABDUL RASHID
Norhanisah JAMALUDIN
Hiroyuki Yoshida
Original Assignee
Universiti Putra Malaysia
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Universiti Putra Malaysia filed Critical Universiti Putra Malaysia
Publication of WO2018056801A1 publication Critical patent/WO2018056801A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/65—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing carbon
    • 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
    • C01B32/15—Nano-sized carbon materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • 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

Definitions

  • This invention relates to a method of preparing carbon quantum dots, and more particularly an acid-free method for carbon quantum dots preparation.
  • Carbon quantum dots are nanosized fragments of carbon typically less than 10 nanometers in size.
  • CQD is a generic term for carbon fragments having any particular shape.
  • CQD having planar structures are also known as Graphene Quantum Dots (GQD).
  • CQD prepared from graphite or graphite-like or graphitized material are also known as GQD.
  • CQD are categorised as zero dimensional nanostructures having high surface area and photoluminescent properties. These characteristics render them as promising material in various applications, such as energy storage, catalysts, and sensors. Furthermore, in their pure carbon form they are non-toxic if compared to their conventional metal counterparts.
  • GQD is usually synthesised by a top-down approach, which starts with large fragments and the fragments are chemically oxidised to reduce the size.
  • the top-down approach is popular because GQD has been found during the ubiquitous preparation of graphene oxide from graphite by chemical oxidation.
  • graphite can also be substituted with various types of carbonaceous starting materials, for example, charcoals and biochars.
  • the GQD is formed by exposing a carbon source to the oxidant, which may include an acid. Separation of the formed GQD from the oxidant is then performed by neutralisation, filtration, and dialysis.
  • the present invention relates to a method of preparing CQD, characterised by: dispersing carbonaceous particles in absolute alcohol or a mixture of water and alcohol; and heating the dispersion to obtain photoluminescent liquid comprising the CQD.
  • Fig. 1 (a) and (b) are HRTEM images of CQD obtained from coconut shell biochar at different magnifications.
  • Fig. 2 show CQD suspensions prepared at 250 °C using starting samples of (from left to right) coconut shell biochar, kenaf biochar and EFB biochar (a) under ambient light (b) under UV light (365 nm).
  • Fig. 3 is a graph illustrating the photoluminescent spectra for a CQD suspension prepared from EFB biochar at 250°C.
  • the present invention relates to a method of preparing carbon quantum dots (CQD), characterised by:
  • the carbonaceous particles are selected from a group comprising graphite or graphite-like materials including coal, biochar, or a combination thereof.
  • the alcohol is selected from a group comprising ethanol, methanol, propanol, isopropanol, or a combination thereof.
  • the dispersion is heated at a temperature below the critical point of water.
  • the temperature is in a range of 200°C to 350°C.
  • the heating is performed by submerging a container containing the dispersion in a salt bath for 5 to 10 minutes.
  • the carbonaceous particles are subjected to milling before the dispersion step.
  • the carbonaceous particles are subjected to microwaving after the milling step.
  • the microwaving is performed for up to 60 seconds for every gram of the carbonaceous particles.
  • Carbonaceous particles were ball milled to reduce the size of the particles from micrometer to nanometer.
  • the biochar was milled for 24 hours to yield a particle size distribution of less than 500 nanometers, with about 50% being less than 200 nanometers.
  • 0.6 g of the particles were dispersed in a mixture containing water and ethanol in a ratio (by volume) of 1 :1 by sonication for 15 minutes.
  • the dispersion was then poured into a steel cylindrical container with swagelok end caps that were carefully tightened to avoid leaking.
  • the container was immersed in a salt bath at a temperature of 250°C for five minutes.
  • the container was removed from the salt bath and allowed to cool down prior to the collection of the mixture.
  • the mixture was subjected to centrifugation at 4000 rpm for five minutes to separate any remaining solids from the liquid.
  • the liquid was then qualitatively examined for fluorescence by shining ultraviolet (UV) light onto the samples. CQD containing liquid were shown to emit blue light.
  • UV ultraviolet
  • FIGS. 1 and 2b show CQD suspensions prepared using different types of biochar at 250 °C under ambient light and UV light at 365 nm, respectively.
  • FIG. 3 illustrates the photoluminescent spectra for a CQD suspension obtained from EFB biochar prepared at 250°C.
  • CQD prepared using different water:alcohol ratios, different types of alcohol and different types of carbonaceous particles were shown to emit light ranging from green to blue.
  • the electrochemical and photochemical properties of CQD find applications in the fields of energy storage (supercapacitor and dye sensitised solar cell) and biosensing platforms.
  • CQD conducting polymers
  • Low cost dye-sensitised solar cell which is the third generation solar cell, has attracted considerable attention due to its advantages, such as cost effective, simple, and environmental friendly fabrication process.
  • the synthetic dyes tailored for its visible region is not sensitive to the UV light.
  • a stroke-shift material such as CQD is provided to contribute to quantum excitation effects that will improve the dye sensitised solar cell (DSSC) light absorption. This is achieved by incorporating CQD in the electrolytes in which the UV light is converted into visible light that can be absorbed by the dye, and thus improving the system efficiency.
  • CQD are excellent candidates for biosensing applications due to its photochemical properties.
  • the CQD can be important marker molecule for monitoring uric acid level in body fluids.
  • the existing methods involve laborious procedures, expensive reagents, and limited specificity and sensitivity. Therefore, it is necessary to develop simple, accurate, and sensitive methods for the determination of uric acid level , which can be achieved by the use of CQD conjugated dual enzymes (uricase/horseradish peroxidise).
  • the principle of detection is based on fluorescence quenching of CQD which is induced by enzymatic reaction. This biosensing system is expected to give high sensitivity and specificity with the utilisation of CQD.

Abstract

The present invention relates to a method of preparing carbon quantum dots (CQD), characterised by: dispersing carbonaceous particles in absolute alcohol or a mixture of water and alcohol; and heating the dispersion to obtain photoluminescent liquid comprising the CQD.

Description

PREPARATION OF CARBON QUANTUM DOTS
Background of the Invention
Field of the Invention
This invention relates to a method of preparing carbon quantum dots, and more particularly an acid-free method for carbon quantum dots preparation.
Description of Related Arts
Carbon quantum dots (CQD or C-dots) are nanosized fragments of carbon typically less than 10 nanometers in size. CQD is a generic term for carbon fragments having any particular shape. Usually CQD prepared from a bottom-up approach would have spherical structures whereas CQD prepared from a top-down approach would have planar structures. CQD having planar structures are also known as Graphene Quantum Dots (GQD). CQD prepared from graphite or graphite-like or graphitized material are also known as GQD. CQD are categorised as zero dimensional nanostructures having high surface area and photoluminescent properties. These characteristics render them as promising material in various applications, such as energy storage, catalysts, and sensors. Furthermore, in their pure carbon form they are non-toxic if compared to their conventional metal counterparts.
GQD is usually synthesised by a top-down approach, which starts with large fragments and the fragments are chemically oxidised to reduce the size. The top-down approach is popular because GQD has been found during the ubiquitous preparation of graphene oxide from graphite by chemical oxidation. Using the same approach, graphite can also be substituted with various types of carbonaceous starting materials, for example, charcoals and biochars.
Chemical oxidation processes use large amounts of acids and oxidising agents. Moreover, bases are used for the neutralisation of acids. However, the use of hazardous chemicals is undesirable, especially for large scale production. The neutralisation process in turn, produces large amounts of salts that need washing. The washing of GQD requires a tedious dialysis process as the small sized GQD have to be handled with extreme care. Despite the aforementioned drawbacks, chemical oxidation process is routinely used because of its effectiveness in GQD production.
An example of the method of making GQD using an oxidant is disclosed in WO 2014/179708. In this prior art, the GQD is formed by exposing a carbon source to the oxidant, which may include an acid. Separation of the formed GQD from the oxidant is then performed by neutralisation, filtration, and dialysis.
Recently alternative approaches have been used to produce GQD by using different chemicals, such as oxone (Shin, Y. et al., 2015) and sodium hypochlorite (Zhou, X. et al., 2016). However, the use of these chemicals can also lead to harmful complications.
Accordingly, it can be seen in the prior arts that there exists a need to provide a safe, acid-free, and simple method for large scale production of CQD. References
• Shin, Y. et al., Acid-free and Oxone Oxidant-assisted Solvothermal Synthesis of Graphene Quantum Dots using Various Natural Carbon Materials as Resources, Nanoscale, 2015, 7, 5633-5637.
• Zhou, X. et al., Large Scale Production of Graphene Quantum Dots Through the Reaction of Graphene Oxide with Sodium Hypochlorite, RSC
Advances, 2016, 54644-54648.
Summary of Invention
It is an objective of the present invention to provide an acid-free method for preparing CQD. It is also an objective of the present invention to provide a non-toxic method for preparing CQD.
It is yet another objective of the present invention to provide a simple method for large-scale production of CQD.
Accordingly, these objectives may be achieved by following the teachings of the present invention. The present invention relates to a method of preparing CQD, characterised by: dispersing carbonaceous particles in absolute alcohol or a mixture of water and alcohol; and heating the dispersion to obtain photoluminescent liquid comprising the CQD.
Brief Description of the Drawings
The features of the invention will be more readily understood and appreciated from the following detailed description when read in conjunction with the accompanying drawings of the preferred embodiment of the present invention, in which:
Fig. 1 (a) and (b) are HRTEM images of CQD obtained from coconut shell biochar at different magnifications.
Fig. 2 show CQD suspensions prepared at 250 °C using starting samples of (from left to right) coconut shell biochar, kenaf biochar and EFB biochar (a) under ambient light (b) under UV light (365 nm).
Fig. 3 is a graph illustrating the photoluminescent spectra for a CQD suspension prepared from EFB biochar at 250°C.
Detailed Description of the Invention
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting but merely as a basis for claims. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims. As used throughout this application, the word "may" is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words "include," "including," and "includes" mean including, but not limited to. Further, the words "a" or "an" mean "at least one" and the word "plurality" means one or more, unless otherwise mentioned. Where the abbreviations or technical terms are used, these indicate the commonly accepted meanings as known in the technical field. For ease of reference, common reference numerals will be used throughout the figures when referring to the same or similar features common to the figures. The present invention will now be described with reference to Figs. 1 -3.
The present invention relates to a method of preparing carbon quantum dots (CQD), characterised by:
dispersing carbonaceous particles in absolute alcohol or a mixture of water and alcohol; and
heating the dispersion to obtain photoluminescent liquid comprising the CQD.
In a preferred embodiment of the method of preparing the CQD, the carbonaceous particles are selected from a group comprising graphite or graphite-like materials including coal, biochar, or a combination thereof.
In a preferred embodiment of the method of preparing the CQD, the alcohol is selected from a group comprising ethanol, methanol, propanol, isopropanol, or a combination thereof.
In a preferred embodiment of the method of preparing the CQD, the dispersion is heated at a temperature below the critical point of water. In a preferred embodiment of the method of preparing the CQD, the temperature is in a range of 200°C to 350°C. In a preferred embodiment of the method of preparing the CQD, the heating is performed by submerging a container containing the dispersion in a salt bath for 5 to 10 minutes.
In a preferred embodiment of the method of preparing the CQD, the carbonaceous particles are subjected to milling before the dispersion step.
In a preferred embodiment of the method of preparing the CQD, the carbonaceous particles are subjected to microwaving after the milling step. In a preferred embodiment of the method of preparing the CQD, the microwaving is performed for up to 60 seconds for every gram of the carbonaceous particles.
Below is an example of the preparation and applications of CQD from which the advantages of the present invention may be more readily understood. It is to be understood that the following example is for illustrative purpose only and should not be construed to limit the present invention in any way.
Examples
Carbonaceous particles were ball milled to reduce the size of the particles from micrometer to nanometer. In an example of using coconut shell biochar as the carbonaceous particles, the biochar was milled for 24 hours to yield a particle size distribution of less than 500 nanometers, with about 50% being less than 200 nanometers. Then, 0.6 g of the particles were dispersed in a mixture containing water and ethanol in a ratio (by volume) of 1 :1 by sonication for 15 minutes. The dispersion was then poured into a steel cylindrical container with swagelok end caps that were carefully tightened to avoid leaking. The container was immersed in a salt bath at a temperature of 250°C for five minutes. The container was removed from the salt bath and allowed to cool down prior to the collection of the mixture. The mixture was subjected to centrifugation at 4000 rpm for five minutes to separate any remaining solids from the liquid. The liquid was then qualitatively examined for fluorescence by shining ultraviolet (UV) light onto the samples. CQD containing liquid were shown to emit blue light.
In order to improve the yield of CQD, milled particles were microwaved for one minute using a conventional microwave oven before being dispersed in the water-alcohol mixture. This helps to expand and increase the interlayer d-spacing between graphitized sheets. Table 1 shows the CQD yield obtained from coconut shell biochar under different conditions.
Table 1 : Yield of CQD produced from coconut shell biochar under different conditions
Figure imgf000008_0001
3Subcritical conditions: 300°C for 5 minutes
bSonication time: 5 minutes
cMicrowave time: 1 minute Note that the yield of suspended product referred to the amount of particles suspended in the supernatant obtained after centrifuge. This liquid contained small CQD (around 10 nm) as well as relatively larger sheets of graphene platelets (200-300 nm). High-resolution transmission electron microscopy (HRTEM) images of the CQD are shown in Figures 1 a and 1 b.
Different types of biochar result in CQD with different photoluminescent behaviour. Examples of other types of biochar include kenaf and oil palm empty fruit bunch (EFB). Figures 2a and 2b show CQD suspensions prepared using different types of biochar at 250 °C under ambient light and UV light at 365 nm, respectively.
Quantitative analysis of the CQD was carried out using photoluminescent spectroscopy. Figure 3 illustrates the photoluminescent spectra for a CQD suspension obtained from EFB biochar prepared at 250°C.
In other embodiments, CQD prepared using different water:alcohol ratios, different types of alcohol and different types of carbonaceous particles were shown to emit light ranging from green to blue. The electrochemical and photochemical properties of CQD find applications in the fields of energy storage (supercapacitor and dye sensitised solar cell) and biosensing platforms.
Reports on the use of CQD as electrode materials in the field of energy storage are very limited. Meanwhile, conducting polymers (CP) are well-studied pseudocapacitive material used as the electrode material for supercapacitors due to the low cost of monomers, simple synthesis process, environmental stability, and high specific pseudocapacitance. However, CP swell and contract substantially on charge and discharge, respectively. Consequently, the life cycle is poor compared with carbon-based supercapacitors. Conducting polymer/carbon quantum dot (CP/CQD) composites can be developed as new electrode material for supercapacitor as the advantages of one type could complement with the drawbacks of another. It is expected that the synergistic effect of both materials can provide outstanding supercapacitor performance.
Low cost dye-sensitised solar cell, which is the third generation solar cell, has attracted considerable attention due to its advantages, such as cost effective, simple, and environmental friendly fabrication process. However, the synthetic dyes tailored for its visible region is not sensitive to the UV light. To overcome this problem, a stroke-shift material such as CQD is provided to contribute to quantum excitation effects that will improve the dye sensitised solar cell (DSSC) light absorption. This is achieved by incorporating CQD in the electrolytes in which the UV light is converted into visible light that can be absorbed by the dye, and thus improving the system efficiency.
CQD are excellent candidates for biosensing applications due to its photochemical properties. The CQD can be important marker molecule for monitoring uric acid level in body fluids. The existing methods involve laborious procedures, expensive reagents, and limited specificity and sensitivity. Therefore, it is necessary to develop simple, accurate, and sensitive methods for the determination of uric acid level , which can be achieved by the use of CQD conjugated dual enzymes (uricase/horseradish peroxidise). The principle of detection is based on fluorescence quenching of CQD which is induced by enzymatic reaction. This biosensing system is expected to give high sensitivity and specificity with the utilisation of CQD. Although the present invention has been described with reference to specific embodiments, also shown in the appended figures, it will be apparent for those skilled in the art that many variations and modifications can be done within the scope of the invention as described in the specification and defined in the following claims.

Claims

Claims I/We claim:
1 . A method of preparing carbon quantum dots (CQD), characterised by:
dispersing carbonaceous particles in absolute alcohol or a mixture of water and alcohol; and
heating the dispersion to obtain photoluminescent liquid comprising the CQD.
2. The method according to claim 1 , wherein the carbonaceous particles are selected from a group comprising graphite or graphite-like materials, including coal, biochar, or a combination thereof.
3. The method according to claim 1 , wherein the alcohol is selected from a group comprising ethanol, methanol, propanol, isopropanol, or a combination thereof.
4. The method according to claim 1 , wherein up to 1 g of the carbonaceous particles are dispersed in every 6 ml of the absolute alcohol or the mixture of water and alcohol to obtain the dispersion.
5. The method according to claim 1 , wherein the dispersion is heated at a temperature below the critical point of water.
6. The method according to claim 5, wherein the temperature is in a range of 200°C to 350°C.
7. The method according to claim 6, wherein the heating is performed by submerging a container containing the dispersion in a salt bath for 5 to 10 minutes.
8. The method according to claim 1 , wherein the carbonaceous particles are subjected to milling before the dispersion step.
9. The method according to claim 8, wherein the carbonaceous particles are subjected to microwaving after the milling step.
10. The method according to claim 9, wherein the microwaving is performed for up to 60 seconds for every gram of the carbonaceous particles.
PCT/MY2017/050055 2016-09-22 2017-09-11 Preparation of carbon quantum dots WO2018056801A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MYPI2016703467A MY195075A (en) 2016-09-22 2016-09-22 Preparation of Carbon Quantum Dots
MYPI2016703467 2016-09-22

Publications (1)

Publication Number Publication Date
WO2018056801A1 true WO2018056801A1 (en) 2018-03-29

Family

ID=61690964

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/MY2017/050055 WO2018056801A1 (en) 2016-09-22 2017-09-11 Preparation of carbon quantum dots

Country Status (2)

Country Link
MY (1) MY195075A (en)
WO (1) WO2018056801A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108671888A (en) * 2018-05-21 2018-10-19 徐州工程学院 A kind of N-CDs@δ-MnO2The preparation method and application of nanocomposite
CN108975309A (en) * 2018-09-03 2018-12-11 南京林业大学 The method and its application of Water-soluble carbon quantum dot and fluorescent ink are prepared using cyanobacteria
CN109019560A (en) * 2018-10-16 2018-12-18 吕梁学院 A kind of preparation method of coal-based carbon point
CN109777411A (en) * 2019-03-20 2019-05-21 南宁师范大学 The preparation method of cobalt doped magnetism carbon quantum dot and the method for detecting uric acid
CN109956917A (en) * 2019-03-19 2019-07-02 华中科技大学 A kind of method and product of biomass coproducing furfural and carbon quantum dot
CN110093157A (en) * 2017-09-29 2019-08-06 相昌盛 A method of fluorescence nano structure is extracted from carbon source by reduction reaction
WO2020121119A1 (en) * 2018-12-14 2020-06-18 Zaderko Alexander The process for obtaining of fluoralkylated carbon quantum dots
CN111547704A (en) * 2020-05-06 2020-08-18 大连海事大学 Method and device for preparing carbon quantum dots based on liquid phase pulse plasma effect

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080113448A1 (en) * 2005-10-27 2008-05-15 Clemson University Fluorescent Carbon Nanoparticles
US20080182984A1 (en) * 2007-01-25 2008-07-31 Canon Kabushiki Kaisha Method for producing a pigment
JP2014019599A (en) * 2012-07-17 2014-02-03 Japan Health Sciences Foundation Method for preparing highly-dispersible nanomaterial
CN103950913A (en) * 2014-03-31 2014-07-30 南京航空航天大学 Preparation method of water-soluble fluorescent carbon nanopowder
CN103980893A (en) * 2014-05-30 2014-08-13 太原理工大学 One-step preparation method of multicolor fluorescent functionalized graphene quantum dots
WO2015106437A1 (en) * 2014-01-17 2015-07-23 深圳粤网节能技术服务有限公司 Large-scale preparation method for graphene quantum dots

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080113448A1 (en) * 2005-10-27 2008-05-15 Clemson University Fluorescent Carbon Nanoparticles
US20080182984A1 (en) * 2007-01-25 2008-07-31 Canon Kabushiki Kaisha Method for producing a pigment
JP2014019599A (en) * 2012-07-17 2014-02-03 Japan Health Sciences Foundation Method for preparing highly-dispersible nanomaterial
WO2015106437A1 (en) * 2014-01-17 2015-07-23 深圳粤网节能技术服务有限公司 Large-scale preparation method for graphene quantum dots
CN103950913A (en) * 2014-03-31 2014-07-30 南京航空航天大学 Preparation method of water-soluble fluorescent carbon nanopowder
CN103980893A (en) * 2014-05-30 2014-08-13 太原理工大学 One-step preparation method of multicolor fluorescent functionalized graphene quantum dots

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SASIKALA, S. P. ET AL.: "High Yield Synthesis of Aspect Ratio Controlled Graphenic Materials from Anthracite Coal in Supercritical Fluids", ACS NANO, vol. 10, no. 5, May 2016 (2016-05-01), pages 5293 - 5303, XP055452769, ISSN: 1936-0851 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110093157A (en) * 2017-09-29 2019-08-06 相昌盛 A method of fluorescence nano structure is extracted from carbon source by reduction reaction
CN110093157B (en) * 2017-09-29 2022-06-03 相昌盛 Method for extracting fluorescent nanostructure from carbon source through reduction reaction
CN108671888A (en) * 2018-05-21 2018-10-19 徐州工程学院 A kind of N-CDs@δ-MnO2The preparation method and application of nanocomposite
CN108975309A (en) * 2018-09-03 2018-12-11 南京林业大学 The method and its application of Water-soluble carbon quantum dot and fluorescent ink are prepared using cyanobacteria
CN109019560A (en) * 2018-10-16 2018-12-18 吕梁学院 A kind of preparation method of coal-based carbon point
WO2020121119A1 (en) * 2018-12-14 2020-06-18 Zaderko Alexander The process for obtaining of fluoralkylated carbon quantum dots
CN109956917A (en) * 2019-03-19 2019-07-02 华中科技大学 A kind of method and product of biomass coproducing furfural and carbon quantum dot
CN109777411A (en) * 2019-03-20 2019-05-21 南宁师范大学 The preparation method of cobalt doped magnetism carbon quantum dot and the method for detecting uric acid
CN109777411B (en) * 2019-03-20 2022-04-12 南宁师范大学 Preparation method of cobalt-doped magnetic carbon quantum dots and method for detecting uric acid
CN111547704A (en) * 2020-05-06 2020-08-18 大连海事大学 Method and device for preparing carbon quantum dots based on liquid phase pulse plasma effect
CN111547704B (en) * 2020-05-06 2022-11-01 大连海事大学 Method and device for preparing carbon quantum dots based on liquid phase pulse plasma effect

Also Published As

Publication number Publication date
MY195075A (en) 2023-01-09

Similar Documents

Publication Publication Date Title
WO2018056801A1 (en) Preparation of carbon quantum dots
Zhou et al. Wet‐chemical synthesis of hollow red‐phosphorus nanospheres with porous shells as anodes for high‐performance lithium‐ion and sodium‐ion batteries
Chen et al. Green synthesis of graphene quantum dots from cotton cellulose
Li et al. Size‐dependent optical absorption of layered mos2 and dna oligonucleotides induced dispersion behavior for label‐free detection of single‐nucleotide polymorphism
Zhu et al. Hydrothermal preparation of photoluminescent graphene quantum dots characterized excitation‐independent emission and its application as a bioimaging reagent
Gu et al. Facile synthesis and photoluminescence characteristics of blue-emitting nitrogen-doped graphene quantum dots
Zhu et al. Mechanism of enhanced carbon cathode performance by nitrogen doping in lithium–sulfur battery: an X-ray absorption spectroscopic study
Kumar et al. Activated carbon modified with carbon nanodots as novel electrode material for supercapacitors
Rimal et al. Novel synthesis of high-thermal stability carbon dots and nanocomposites from oleic acid as an organic substrate
Sun et al. Microwave‐assisted in situ synthesis of graphene/PEDOT hybrid and its application in supercapacitors
Lin et al. Hollow hierarchical carbon spheres decorated with ultrathin molybdenum disulfide nanosheets as high‐capacity electrode materials for asymmetric supercapacitors
Du et al. Green synthesis of fluorescent carbon quantum dots and carbon spheres from pericarp
Jovanović et al. Enhancing photoluminescence of graphene quantum dots by thermal annealing of the graphite precursor
Li et al. Free-radical-assisted rapid synthesis of graphene quantum dots and their oxidizability studies
Wei et al. High yield controlled synthesis of nano-graphene oxide by water electrolytic oxidation of glassy carbon for metal-free catalysis
He et al. Coal based carbon dots: Recent advances in synthesis, properties, and applications
Zhu et al. Microwave synthesis of amphiphilic carbon dots from xylose and construction of luminescent composites with shape recovery performance
Guo et al. Mg− O‐Bridged Polypyrrole/g‐C3N4 Nanocomposites as Efficient Visible‐Light Catalysts for Hydrogen Evolution
Huang et al. Nitrogen-doped carbon quantum dot-anchored hydrogels for visual recognition of dual metal ions through reversible fluorescence response
Smrithi et al. Heteroatom modified hybrid carbon quantum dots derived from Cucurbita pepo for the visible light driven photocatalytic dye degradation
Ran et al. A thermal-assisted electrochemical strategy to synthesize carbon dots with bimodal photoluminescence emission
Shi et al. Preparation, characterization and the supercapacitive behaviors of electrochemically reduced graphene quantum dots/polypyrrole hybrids
Hou et al. Application of coal-based carbon dots for photocatalysis and energy storage: a minireview
Hao et al. Synthesis of blue fluorescent carbon dots and their application in detecting mercury and iodine based on “off–on” mode
Zhang et al. Preparation of polyaniline/porous carbon spheres derived from γ-cyclodextrin for supercapacitors

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17853512

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17853512

Country of ref document: EP

Kind code of ref document: A1