CN112408362B - Carbon quantum dot and preparation method and application thereof - Google Patents
Carbon quantum dot and preparation method and application thereof Download PDFInfo
- Publication number
- CN112408362B CN112408362B CN201910772740.XA CN201910772740A CN112408362B CN 112408362 B CN112408362 B CN 112408362B CN 201910772740 A CN201910772740 A CN 201910772740A CN 112408362 B CN112408362 B CN 112408362B
- Authority
- CN
- China
- Prior art keywords
- carbon
- nitrogen
- doped
- carbon quantum
- prepared
- 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.)
- Active
Links
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
- C01B32/15—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
- B82Y40/00—Manufacture or treatment of nanostructures
-
- 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
Abstract
The invention provides a carbon quantum dot and a preparation method and application thereof. The preparation method comprises the following steps: 1) compounding a carbon material on carbon cloth to prepare an electrode; 2) and electrolyzing in electrolyte by taking the electrode as an anode to prepare the carbon quantum dot. The nitrogen-doped carbon quantum dot prepared by the preparation method can be applied to iron ion detection; the iron-nitrogen doped carbon quantum dot prepared by the preparation method can be applied to copper ion detection. The preparation method utilizes the carbon cloth smear as the anode for electrolytic oxidation stripping to prepare the carbon quantum dots, is suitable for preparing the undoped carbon quantum dots and the doped carbon quantum dots, and has higher yield of the carbon quantum dots.
Description
Technical Field
The invention relates to the field of carbon nanomaterial science, in particular to a carbon quantum dot preparation method capable of repeatedly using a carbon cloth smear to prepare carbon quantum dots.
Background
The current preparation methods of carbon dots mainly include two types, namely a bottom-up method and a top-down method, wherein the bottom-up method is to polymerize a small-molecule carbon source into carbon quantum dots, and the bottom-up method mainly includes a microwave method, a template method, a hydrothermal method and the like, wherein the separation and purification of the carbon quantum dots prepared by the microwave method are difficult, the template method is required to be separated when used, and the hydrothermal method is not beneficial to industrial mass production. The top-down method is to etch a macromolecular carbon source into micromolecular carbon quantum dots, and mainly comprises an arc discharge method, a chemical oxidation method, an electrochemical oxidation method and the like, wherein the arc discharge method has the defect of high impurity yield and low yield, the chemical oxidation method can generate a large amount of waste acid to pollute the environment, the electrochemical oxidation method has high yield and adjustable particle size, the industrial graphite rods, carbon black and the like mainly used in the current electrochemical oxidation are used as electrodes, the electrode raw materials are all undoped pure carbon materials, and the prepared carbon quantum dots are also undoped carbon quantum dots, so that certain limitation of practical application is brought, and the carbon quantum dots modified and passivated by the elements cannot be prepared.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method of a carbon quantum dot, which is used for preparing the carbon quantum dot by taking an electrode prepared from a composite carbon material with carbon cloth as a substrate as an anode for electrolytic oxidation stripping, and is suitable for preparing the undoped carbon quantum dot and the doped carbon quantum dot.
The invention provides a preparation method of a carbon quantum dot, wherein the method comprises the following steps:
1) compounding a carbon material on carbon cloth to prepare an electrode; the carbon material includes undoped carbon and doped carbon;
2) electrolyzing the electrode serving as an anode in electrolyte to prepare the carbon quantum dots; the carbon quantum dots are distributed in the electrolyzed electrolyte.
In the above method, the carbon material may be one or a combination of two or more of doped carbon and undoped carbon, and the doped carbon may be carbon doped with one element or carbon doped with a plurality of elements (two or more elements). The undoped carbon can be carbon materials such as undoped porous carbon, natural graphite and the like; the doped carbon can be carbon materials such as doped porous carbon, doped graphite and the like.
In the above method, preferably, the carbon material includes at least one of undoped carbon, nitrogen-doped carbon, and iron-nitrogen-doped carbon; more preferably, the carbon material comprises at least one of graphene, undoped porous carbon, nitrogen-doped graphene, nitrogen-doped porous carbon, iron-nitrogen-doped porous carbon; further preferably, the carbon material includes graphene prepared by using graphene oxide and a reducing agent, undoped porous carbon prepared by using a carbon source and a template, nitrogen-doped graphene prepared by using graphene oxide, a reducing agent and a nitrogen source (the reducing agent and the nitrogen source may be the same substance or different substances, for example, urea may be used as the nitrogen source and the reducing agent), nitrogen-doped porous carbon prepared by using a carbon source, a nitrogen source and a template (the carbon source and the nitrogen source may be the same substance or different substances, for example, 1,10 phenanthroline may be used as both the carbon source and the nitrogen source), a carbon source, at least one of a nitrogen source, an iron source and iron-nitrogen doped porous carbon prepared by a template agent (the carbon source and the nitrogen source can be the same substance or different substances, for example, 1,10 phenanthroline can be used as both the carbon source and the nitrogen source); most preferably, the carbon material includes at least one of graphene prepared by using graphene oxide and hydrazine hydrate, undoped porous carbon prepared by calcining triphenylmethane and a magnesium oxide template, nitrogen-doped graphene prepared by using graphene oxide, urea and the like, nitrogen-doped porous carbon prepared by calcining 1,10 phenanthroline and a magnesium oxide template, and iron-nitrogen-doped porous carbon generated by calcining 1,10 phenanthroline, ferric trichloride and a magnesium oxide template.
In the above method, preferably, the carbon material comprises one or a combination of two or more of doped carbons; more preferably, the carbon material comprises at least one of nitrogen-doped carbon and iron-nitrogen-doped carbon; further preferably, the carbon material comprises at least one of nitrogen-doped graphene, nitrogen-doped porous carbon, iron-nitrogen-doped porous carbon; for example, the carbon material may include nitrogen-doped graphene prepared using graphene oxide, a reducing agent, and a nitrogen source (the reducing agent and the nitrogen source may be the same substance or different substances, for example, urea may be used as both the nitrogen source and the reducing agent), nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source, and a template (the carbon source and the nitrogen source may be the same substance or different substances, for example, 1,10 phenanthroline may be used as both the carbon source and the nitrogen source, and may be used as the nitrogen source), and at least one of iron-nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source, an iron source, and a template (the carbon source and the nitrogen source may be the same substance or different substances, for example, 1,10 phenanthroline may be used as both the carbon source and the nitrogen source); for another example, the carbon material may include nitrogen-doped graphene prepared using graphene oxide, urea, and the like; the method comprises the steps of calcining 1,10 phenanthroline and a magnesium oxide template to prepare nitrogen-doped porous carbon, and calcining 1,10 phenanthroline, adding ferric trichloride and calcining a magnesium oxide template to generate at least one of iron-nitrogen-doped porous carbon.
In the above method, preferably, the compounding of the carbon material onto the carbon cloth is performed by a coating method, specifically according to the following steps: A. dispersing a carbon material and a binder into a solvent to form a dispersion slurry; B. and coating the dispersion slurry on carbon cloth, and then drying to prepare the electrode. In step a, dispersing the carbon material and the binder into the solvent is preferably achieved by a method comprising the steps of: adding the carbon material and the binder into a solvent for grinding (the grinding time is preferably not less than 5min), so as to disperse the carbon material and the binder into the solvent; the drying temperature is preferably 80-100 ℃; the drying time is preferably 5-16 h.
In the above method, preferably, the solvent used for compounding the carbon material onto the carbon cloth includes at least one of ethanol, water (e.g., pure water); more preferably, the solvent is ethanol.
In the above method, preferably, the binder used for compounding the carbon material onto the carbon cloth includes at least one of Polytetrafluoroethylene (PTFE) binder, perfluorosulfonic acid-polytetrafluoroethylene copolymer (Nafion) binder, phenol resin, and polyvinylidene fluoride (PVDF). More preferably, the binder comprises at least one of a Polytetrafluoroethylene (PTFE) binder, a perfluorosulfonic acid-polytetrafluoroethylene copolymer (Nafion) binder.
In the method, the particle size of the prepared carbon quantum dots can be regulated and controlled by controlling the using amount of the binder. Preferably, the dosage ratio of the carbon material to the binder is 9.5mg:0.5 μ L-5mg:5 μ L; more preferably 3mg: 1. mu.L-19 mg: 1. mu.L; further preferably 4mg: 1. mu.L-9 mg: 1. mu.L; most preferably 17mg: 3. mu.L.
In the above method, preferably, the carbon material is coated at 2 to 10mg per square centimeter of the carbon cloth.
In the above method, preferably, the counter electrode used for the electrolysis includes at least one of a graphite rod, a platinum sheet electrode, and a platinum wire electrode; more preferably a graphite rod.
In the above method, preferably, the electrolyte contains at least one of sodium hydroxide ethanol aqueous solution, ammonia water, pure water (i.e., deionized water); more preferably an aqueous solution of sodium hydroxide in ethanol; wherein, in the sodium hydroxide ethanol water solution, the concentration of the sodium hydroxide is preferably 0.005-0.1 mol/L; in the sodium hydroxide ethanol water solution, the volume ratio of ethanol to water is preferably 3:1 to 5: 1; the water used for preparing the sodium hydroxide ethanol water solution is preferably pure water; the resistivity of pure water is preferably 18.25 M.OMEGA.per cm at 24 ℃.
In the above method, it is preferable to use an alkaline electrolyte and a binder having excellent alkali resistance during electrolysis, for example, an aqueous solution of sodium hydroxide and ethanol as the electrolyte and PTFE as the binder (the binder PTFE is excellent in alkali resistance and is more excellent in binding effect in the alkaline electrolyte). The electrode prepared in the step 1) can be kept in a stable state during the electrolysis in the step 2), for example, the electrode can be bonded more firmly and is less prone to loosening, and the electrode can keep higher conductivity for a longer time.
In the above method, preferably, in the step 2), the voltage used for the electrolysis is 2 to 10V. The particle size of the prepared carbon quantum dots can be regulated and controlled by controlling the voltage, and the particle size of the carbon quantum dots is increased along with the increase of the voltage.
In the above method, preferably, in step 2), the power source used for electrolysis is a direct current power source.
In the above method, preferably, the step 2) further comprises: and (4) purifying the electrolyzed electrolyte by using carbon quantum dots.
In the above method, preferably, the step of purifying includes: and filtering the electrolyzed electrolyte to remove solid particles and dialyzing. Wherein, the filtration can be performed using a microfiltration membrane, but is not limited thereto, and the microfiltration membrane preferably uses a 0.22 μm microfiltration membrane; the dialysis can be performed using a dialysis bag, but is not limited thereto, and the dialysis bag is preferably a dialysis bag having a molecular weight cut-off of 3500 Da; the dialysis time may be 12-48h, but is not limited thereto. The filter can effectively get rid of binder and large granule carbon piece, and the ion in the electrolyte can be got rid of in the dialysis, and the carbon quantum dot that makes like this not only is purer free from impurity, and the particle diameter is more even moreover.
In the above method, preferably, the step of purifying includes a step of neutralizing a pH value in the electrolytic solution after electrolysis, and removing an organic component contained in the electrolytic solution. In one embodiment, the sodium hydroxide electrolyte in the electrolyte is removed to make the pH neutral, and the organic components contained in the electrolyte are removed.
In the method, preferably, the step of purifying includes the steps of filtering the electrolyzed electrolyte to remove solid particles, dialyzing, neutralizing the pH value of the electrolyzed electrolyte, and removing organic components contained in the electrolyte. In a specific embodiment, the electrolyzed electrolyte is filtered by using a microfiltration membrane (for example, a 0.22 μm microfiltration membrane) to remove solid particles in the electrolyte, dialyzed by using a dialysis bag (for example, a dialysis bag with a molecular weight cut-off of 3500 Da), purified by removing alkali, dried (for example, freeze-dried), and purified by removing ethanol to obtain the carbon quantum dots (generally, the obtained carbon quantum dots are yellow solid powder). The purified carbon quantum dots, especially the carbon quantum dots prepared after drying, are more beneficial to long-term storage, and can be directly used or directly dissolved in pure water and other polar solutions for use.
In a specific embodiment, the preparation method of the carbon quantum dot provided by the invention can be carried out according to the following specific steps:
(1) preparing an electrode: dispersing 10-50mg of doped porous carbon mixed with 0.5-50 mu L of binder in a proper amount of solvent to obtain dispersed slurry; wherein the mass (mg) of the porous carbon doped: the volume (muL) of the binder is 19mg:1 muL to 1mg:1 muL, the dispersion slurry is coated on a carbon cloth with the thickness of 2cm multiplied by 2cm, and the carbon cloth is dried for 5 to 16 hours at the temperature of 80 to 100 ℃ to obtain an electrode; the doped porous carbon comprises at least one of nitrogen doped porous carbon and iron nitrogen doped porous carbon;
(2) preparing the doped carbon quantum dots: taking the prepared electrode as an anode, taking a graphite rod as a counter electrode, taking 100mL of NaOH ethanol water (the ratio of ethanol to water is 3:1-5: 1) solution with the concentration of 0.005-0.1mol/L as electrolyte, switching on a direct current power supply, adjusting the voltage to be 2-10V, and electrolyzing for 8-36h to obtain electrolyte containing doped carbon quantum dots;
(3) and (3) purifying the doped carbon quantum dots: filtering with a 0.22 μm microporous filter membrane to remove particles in the electrolyte, dialyzing with a dialysis bag with a molecular weight cutoff of 3500Da for 16-48h, removing alkali, purifying, freeze-drying the solution after alkali removal, and removing ethanol to obtain the doped carbon quantum dots (generally, nitrogen-doped carbon quantum dots are yellow solid powder).
According to the preparation method of the carbon quantum dot, provided by the invention, the nitrogen-doped carbon quantum dot is prepared by taking an electrode plate prepared by coating a carbon material on carbon cloth as an anode and electrolyzing in electrolyte. The method can realize the preparation of the carbon quantum dots through a simple one-step stripping process; and the carbon material is coated on the carbon cloth to form an anode for electrolysis, so that the aim of preparing the micromolecular carbon quantum dots by electrolytically oxidizing and stripping the carbon material is fulfilled.
The electrode manufactured by coating the carbon cloth with the binder and the mixed carbon material has the characteristics of firm binding, difficult loosening and capability of keeping higher conductivity for a longer time, and the binder and large-particle carbon fragments are easy to remove and can be directly removed by filtering through a 0.22-micron microporous filter membrane in a preferred embodiment. Meanwhile, the carbon quantum is prepared by the method provided by the invention, so that the prepared nitrogen-doped carbon quantum dot has excellent hydrophilic performance and can be directly used or directly dissolved in pure water and other polar solutions for use.
The invention also provides the carbon quantum dot prepared by the preparation method of the carbon quantum dot.
According to an embodiment of the present invention, preferably, the carbon quantum dots are nitrogen-doped carbon quantum dots. The carbon material adopted for preparing the nitrogen-doped carbon quantum dot preferably comprises nitrogen-doped porous carbon prepared by calcining 1,10 phenanthroline and adding a magnesium oxide template.
According to an embodiment of the present invention, preferably, the carbon quantum dots are iron-nitrogen doped carbon quantum dots. The carbon material adopted for preparing the iron-nitrogen doped carbon quantum dot preferably comprises iron-nitrogen doped porous carbon generated by calcining 1,10 phenanthroline, adding ferric trichloride and calcining a magnesium oxide template.
The invention also provides an application of the carbon quantum dot in iron ion detection, wherein the carbon quantum dot is a nitrogen-doped carbon quantum dot.
In the application of the carbon quantum dots in iron ion detection, the linear detection range of detection is preferably 0-1000 [ mu ] mol/L;
in the application of the carbon quantum dots in iron ion detection, the detection limit of the detection is preferably 0.8 μmol/L.
The invention also provides an application of the carbon quantum dot in copper ion detection, wherein the carbon quantum dot is an iron-nitrogen doped carbon quantum dot.
In the application of the carbon quantum dots in the detection of copper ions, preferably, the linear detection range of the detection is 0-500 [ mu ] mol/L;
in the application of the carbon quantum dots in copper ion detection, the detection limit of the detection is preferably 0.8 μmol/L.
According to the preparation method of the carbon quantum dots, the carbon material is compounded on the carbon cloth (in a specific embodiment, the carbon material and the binder are mixed and coated on the carbon cloth) to be used as an electrode, and the carbon quantum dots are prepared from top to bottom. Compared with the prior art, the technical scheme provided by the invention has the following advantages:
1) the preparation method of the carbon quantum dots provided by the invention utilizes the carbon cloth as the conductive current collecting substrate, so that the electrolytic efficiency can be improved, namely the conductivity is better, a certain supporting framework (namely higher strength) and larger contact area can be provided, and the carbon material compounded on the carbon cloth can be fully electrolyzed and stripped into the carbon quantum dots, thereby improving the yield, and the electrolytic yield can reach up to 25.1% in the specific embodiment; in addition, compared with other electrode manufacturing methods such as a tablet pressing method and a packing method, the electrode prepared by compounding the carbon material on the carbon cloth is more suitable for preparing the carbon quantum dots, the tablet pressing method is easy to loosen, the contact area of the packing method is small, and the electrodes prepared by the electrode manufacturing methods are low in conductive efficiency and yield when applied to preparing the carbon quantum dots.
2) The preparation method of the carbon quantum dots provided by the invention has a simpler preparation process, the carbon cloth serving as the substrate can be recycled, and the electrode preparation is continuously carried out and applied to the next preparation of the carbon quantum dots, so that the preparation cost is obviously reduced, the yield is improved, and the economic benefit is higher.
3) The preparation method of the carbon quantum dots has wide applicability, can be suitable for preparing the undoped carbon quantum dots and the doped carbon quantum dots, can be suitable for preparing the carbon quantum dots doped with one element and can also be suitable for preparing the carbon quantum dots doped with multiple elements, and provides a new route for preparing the corresponding doped carbon quantum by electrolyzing different elements and doped porous carbon.
4) According to the preparation method of the carbon quantum dot, the polar functional group is introduced to the surface of the carbon material in the electrolytic process, so that the prepared nitrogen-doped carbon quantum dot has excellent hydrophilic performance and can be directly used or directly dissolved in pure water and other polar solutions for use.
5) The nitrogen-doped carbon quantum dot provided by the invention can be well used for iron ion detection, has good selectivity on iron ions, sensitive response, a large linear detection range (up to 0 mu mol/L-1000 mu mol/L in a specific embodiment) and an excellent detection limit (up to 0.8 mu mol/L in a specific embodiment); the iron-nitrogen doped carbon quantum dot provided by the invention can be well used for copper ion detection, has good selectivity on copper ions, sensitive response, a large linear detection range (up to 1 mu mol/L-500 mu mol/L in a specific embodiment) and an excellent detection limit (up to 0.8 mu mol/L in a specific embodiment);
6) the preparation method of the carbon quantum dots provided by the invention is environment-friendly, simple in process and suitable for batch production.
Drawings
Fig. 1A, 1B, and 1C are an AFM (atomic force microscope) characterization graph, a local thickness statistical graph (a range marked by a white line in fig. 1A), and a particle size distribution histogram of the nitrogen-doped carbon quantum dots provided in example 1, respectively.
Fig. 2 is a fluorescence diagram of the nitrogen-doped carbon quantum dot provided in example 1.
FIG. 3 is a fluorescence plot of the electrolyte provided in comparative example 1.
Fig. 4 is a fluorescence quenching diagram of the nitrogen-doped carbon quantum dot provided in example 1.
Fig. 5 is a graph of iron ion detection of nitrogen-doped carbon quantum dots provided in example 1.
Fig. 6A, 6B, and 6C are an AFM (atomic force microscope) characterization graph, a local thickness statistical graph (a range marked by a white line in fig. 6A), and a particle size distribution histogram of the fe-n doped carbon quantum dots provided in example 2, respectively.
Fig. 7 is a fluorescence diagram of the fe-n doped carbon quantum dot provided in example 2.
Fig. 8 is a fluorescence quenching diagram of the fe-n doped carbon quantum dot provided in example 2.
Fig. 9 is a copper ion detection diagram of the iron-nitrogen doped carbon quantum dots provided in example 2.
Fig. 10 is a comparison graph of XPS (X-ray photoelectron spectroscopy) analysis of nitrogen-doped carbon quantum dots and raw material nitrogen-doped porous carbon of example 1.
Fig. 11A, 11B, and 11C are an AFM characterization graph, a local thickness statistical graph (the range marked by the white line in fig. 11A), and a particle size distribution histogram of the nitrogen-doped carbon quantum dots (3V voltage) provided in example 4, respectively.
Fig. 12 is a fluorescence diagram of the nitrogen-doped carbon quantum dots (3V voltage) provided in example 4.
Fig. 13A, 13B, and 13C are AFM profiles, local thickness statistical graphs (the range marked by the white line in fig. 13A), and particle size distribution histograms of the nitrogen-doped carbon quantum dots (7V voltage) provided in example 5, respectively.
Fig. 14 is a fluorescence diagram of the nitrogen-doped carbon quantum dots (7V voltage) provided in example 5.
Fig. 15A, 15B, and 15C are an AFM (atomic force microscope) characterization map, a local thickness statistical map (the range marked by the white line in fig. 15A), and a particle size distribution histogram of the nitrogen-doped carbon quantum dots provided in example 6, respectively.
Fig. 16 is a fluorescence diagram of the nitrogen-doped carbon quantum dot provided in example 6.
Fig. 17A, 17B, and 17C are an AFM (atomic force microscope) characterization graph, a local thickness statistical graph (the range marked by the white line in fig. 17A), and a particle size distribution histogram of the nitrogen-doped carbon quantum dots provided in example 7, respectively.
Fig. 18 is a fluorescence diagram of the nitrogen-doped carbon quantum dots provided in example 7.
Fig. 19A, 19B, and 19C are an AFM (atomic force microscope) characterization graph, a local thickness statistical graph (a range marked by a white line in fig. 19A), and a particle size distribution histogram of the undoped carbon quantum dots provided in example 3, respectively.
Fig. 20 is a fluorescence plot of undoped carbon quantum dots provided in example 3.
Detailed Description
The technical solutions of the present invention will be described in detail below in order to clearly understand the technical features, objects, and advantages of the present invention, but the present invention is not limited to the practical scope of the present invention.
The atomic force microscope AFM test and the particle size detection, the FL test (namely the fluorescence test), the fluorescence quenching test, the iron ion detection and the copper ion detection are carried out by the following methods:
1. AFM (atomic force microscope) test and particle size detection
The experiment was carried out using an atomic mechanical microscope model Bruker Multimode 8 from Bruker, Germany. Diluting a sample to be detected to ppm level, dripping the sample on the surface of a mica sheet, testing after natural air drying, observing the information such as the appearance, the particle size, the distribution uniformity and the like of the carbon quantum dots, carrying out thickness statistics in a local range, carrying out thickness statistical analysis on an AFM image through Nanoscope analysis in particle size analysis, and obtaining a particle size distribution histogram.
2. FL test (i.e. fluorescence Spectroscopy test)
The fluorescence spectrum is used for analyzing and representing the fluorescence performance of the carbon quantum dots, a sample to be detected is dissolved in pure water (the pure water is 18.25M omega/cm at 24 ℃) and is prepared into a sample with proper concentration of 100 mu g/mL, 1mL of the sample is added into a cuvette, an excitation wavelength is selected every 10nm from 310nm for fluorescence emission spectrum test, and the sample is detected to have no fluorescence emission until the maximum emission wavelength and the optimal excitation wavelength are found out.
3. Fluorescence quenching assay
The selectivity of the carbon quantum dots in pure water to various metal ions is explored by measuring the change of fluorescence intensity, and the specific process comprises the following steps:
(1) deionized water is added into the carbon quantum dot powder obtained by freeze drying to prepare 100 mug/mL carbon quantum dot aqueous solution;
(2) respectively preparing Fe with the ion concentration of 1mmol/L3+Aqueous solution, Pb2+Aqueous solution, Co2+Aqueous solution, Zn2+Aqueous solution, Ca2+Aqueous solution, Ba2+Aqueous solution, Ni2+Aqueous solution, Cu2+Aqueous solution, K+Aqueous solution, Mg2+Aqueous solution, Na+An aqueous solution;
(3) sequentially mixing 0.6mL of each metal ion aqueous solution prepared in the step (2) with 0.4mL of carbon quantum dot aqueous solution prepared in the step (1), recording the fluorescence emission intensity of the carbon quantum dot aqueous solution at an excitation wavelength of 360nm, marking the mixture as F, simultaneously mixing 0.6mL of deionized water with 0.4mL of carbon quantum dot aqueous solution prepared in the step (1) to obtain a blank sample, recording the fluorescence emission intensity of the carbon quantum dot aqueous solution at an excitation wavelength of 360nm, and marking the mixture as F0Will F/F0And performing histogram analysis on the corresponding metal ion species.
4. Iron ion detection
(1) Adding 400 mu L of aqueous solution of carbon quantum dots with the concentration of 100 mu g/mL into 2mL of aqueous solution at room temperature to obtain a mixed solution a; adding 400 mu L of iron ion aqueous solution with certain concentration into the mixed solution a to obtain mixed solution b; shaking the obtained mixed solution b for several minutes to ensure sufficient mixing, and then standing for 5 minutes to achieve stable fluorescence intensity; adding 1mL of the mixed solution b after standing in the step into a fluorescence cuvette, and recording the fluorescence emission intensity of the mixed solution b under the excitation wavelength of 360nm, wherein the mark is F;
(2) repeating the operation of step (1), wherein the concentration of the iron ion aqueous solution added in step (1) is changed;
(3) repeating step (1) in which the aqueous iron ion solution is exchanged for deionized water as a blank, and the measured fluorescence emission intensity, labeled F0；
(4) Dividing F measured in the step (1) and the step (2) by F measured in the step (3) respectively0Is denoted as F/F0(ii) a F/F0Corresponding to Fe3+And (3) performing linear fitting on the concentration (namely the concentration of the iron ions in the iron ion aqueous solution added in the step (1) and the step (2)).
Repeating the above steps (1) - (4) three times to draw F/F0Corresponding to Fe2+Concentration profile, standard deviation calculated and measured at F/F0Corresponding to Fe2+Standard deviation is plotted as error bars in the plot of concentration (i.e., giving F/F)0Corresponding to Fe2+Error bars for each data point in the concentration dependence plot).
5. Copper ion detection
(1) Adding 400 mu L of carbon quantum dot aqueous solution with the concentration of 100 mu g/mL into 2mL of aqueous solution at room temperature to obtain a mixed solution a; adding 400 mu L of copper ion aqueous solution with certain concentration into the mixed solution a to obtain mixed solution b; shaking the obtained mixed solution b for several minutes to ensure sufficient mixing, and then standing for 5 minutes to achieve stable fluorescence intensity; adding 1mL of the mixed solution b after standing in the step into a fluorescence cuvette, and recording the fluorescence emission intensity of the mixed solution b under the excitation wavelength of 360nm, wherein the mark is F;
(2) repeating the operation of step (1) in which the concentration of the aqueous solution of copper ions added in step (1) is changed;
(3) repeating step (1) in which the aqueous solution of copper ions is exchanged for deionized water as a blank and the fluorescence emission intensity measured, labeled F0；
(4) Dividing F measured in the step (1) and the step (2) by F measured in the step (3) respectively0Is marked as F/F0(ii) a F/F0Corresponding to Cu2+And (3) performing linear fitting on the concentration (namely the concentration of the copper ions in the copper ion aqueous solution added in the step (1) and the step (2)).
Repeating the above steps (1) - (4) three times to draw F/F0Corresponding to Cu2+Concentration profile, standard deviation calculated and measured at F/F0Corresponding to Cu2+Standard deviation is plotted as error bars (i.e., giving F/F) in the plot of concentration0Corresponding to Cu2+Error bars for each data point in the concentration dependence plot).
Example 1
The embodiment provides a method for preparing nitrogen-doped carbon quantum dots, wherein the method comprises the following steps:
1) weighing 25.5mg of nitrogen-doped porous carbon, mixing 4.5 mu L of PTFE binder, adding into a mortar, adding _2mL of ethanol, grinding until uniformly dispersed slurry is formed, then directly coating on 2cm × 2cm of carbon cloth, and drying at 80 ℃ for 12 hours to obtain an electrode;
2) taking the electrode obtained in the step 1) as an anode, taking a graphite rod as a counter electrode, taking a sodium hydroxide ethanol aqueous solution (which is prepared from 30mgNaOH, 35mL ethanol and 8mL deionized water, wherein the resistivity of the deionized water at 24 ℃ is 18.25M omega/cm) as an electrolyte, switching on a direct current power supply, adjusting the voltage to 5V, and electrolyzing for 36h to obtain the electrolyte containing the nitrogen-doped carbon quantum dots;
3) and filtering by using a 0.22-micron microporous filter membrane to remove black particles in the electrolyte, dialyzing by using a dialysis bag with the molecular weight cutoff of 3500Da for 48h to remove NaOH, removing ethanol by rotary evaporation at 40 ℃, and then freeze-drying to obtain the nitrogen-doped carbon quantum dot.
The preparation method of the nitrogen-doped porous carbon comprises the following steps: 1.5mmol of 1, 10-phenanthroline and 1g of MgO template agent are dissolved in 100mL of ethanol and stirred for 12 hours, and the ethanol solvent is removed by rotary evaporation to obtain solid powder; calcining the obtained black solid in an argon atmosphere at 800 ℃ (the heating rate is 10 ℃/min) for 2h to obtain black solid powder; and dispersing the obtained black solid powder in 100mL of diluted hydrochloric acid with the concentration of 1mol/L, stirring at normal temperature for 30min to remove the MgO template agent, and drying for 6h to obtain the nitrogen-doped porous carbon.
Example 2
This example provides a method for preparing fe-n doped carbon quantum dots, wherein the method is different from example 1 only in that the carbon material used is fe-n doped porous carbon (rather than n doped porous carbon), and the other steps are the same as those of example 1.
The preparation method of the iron-nitrogen doped porous carbon comprises the following steps: 0.5mmol of FeCl3·6H2Dissolving O, 1.5mmol of 1, 10-phenanthroline and 1g of MgO template agent in 100mL of ethanol, stirring for 12h, and removing the ethanol solvent by rotary evaporation to obtain solid powder; calcining the obtained black solid in an argon atmosphere at 800 ℃ (the heating rate is 10 ℃/min) for 2h to obtain black solid powder; and dispersing the obtained black solid powder in 100mL of dilute hydrochloric acid with the concentration of 1mol/L, stirring at 80 ℃ for 2h to remove unstable iron particles generated on the surface, and drying for 6h to obtain the iron-nitrogen doped porous carbon.
Example 3
This example provides a method for preparing carbon quantum dots, which is different from example 1 only in that the carbon material used is undoped porous carbon (not nitrogen-doped porous carbon), and the other steps are the same as those of example 1.
The preparation method of the undoped porous carbon comprises the following steps: dissolving 1.5mmol of triphenylmethane and 1g of MgO template agent in 100mL of ethanol, stirring for 12h, and removing the ethanol solvent by rotary evaporation to obtain solid powder; calcining the obtained solid powder at 800 ℃ under an argon atmosphere (with the heating rate of 10 ℃/min) for 2h to obtain black solid powder; and dispersing the obtained black solid powder in 100mL of diluted hydrochloric acid with the concentration of 1mol/L, stirring at normal temperature for 30min to remove the MgO template agent, and drying for 6h to obtain the undoped porous carbon.
Example 4
This example provides a method for preparing nitrogen-doped carbon quantum dots, wherein the method is different from example 1 only in that, in step 2), the voltage is adjusted to 3V instead of 5V, and the other steps are the same as the method for preparing example 1.
Example 5
This example provides a method for preparing nitrogen-doped carbon quantum dots, wherein the method is different from example 1 only in that, in step 2), the adjustment voltage is 7V instead of 5V, and the other steps are the same as the preparation method of example 1.
Example 6
This example provides a method for preparing nitrogen-doped carbon quantum dots, wherein the method is different from example 1 only in that 24mg (instead of 25.5mg) of nitrogen-doped porous carbon is weighed in step 1) and 6 μ L (instead of 4.5 μ L) of PTFE binder (4mg:1 μ L) is mixed, and the other steps are the same as the preparation method of example 1.
Example 7
This example provides a method for preparing nitrogen-doped carbon quantum dots, wherein the method is different from example 1 only in that 27mg (instead of 25.5mg) of nitrogen-doped porous carbon is weighed in step 1) and 3 μ L (instead of 4.5 μ L) of PTFE binder (9mg:1 μ L) is mixed, and the other steps are the same as the preparation method of example 1.
Comparative example 1
1) Adding 4.5 mu L of PTFE binder into a mortar, adding 2mL of ethanol, grinding until uniformly dispersed slurry is formed, then directly coating the slurry on a carbon cloth with the size of 2cm multiplied by 2cm, and drying for 12h at the temperature of 80 ℃ to obtain an electrode;
2) taking the electrode obtained in the step 1) as an anode, taking a graphite rod as a counter electrode, taking a sodium hydroxide ethanol aqueous solution (which is prepared from 30mgNaOH, 35mL ethanol and 8mL deionized water, wherein the resistivity of the deionized water at 24 ℃ is 18.25M omega/cm) as an electrolyte, switching on a direct current power supply, adjusting the voltage to be 5V, and electrolyzing for 36h to obtain the electrolyte;
3) filtering with 0.22 μm microporous membrane to remove black particulate matter in the electrolyte, dialyzing with a dialysis bag with molecular weight cutoff of 3500Da for 48h to remove NaOH, removing ethanol by rotary evaporation at 40 deg.C to obtain the reference sample solution, and performing fluorescence spectrum test on the reference sample solution to verify whether carbon dots are generated.
Experimental example 1
The nitrogen-doped carbon quantum dots prepared in example 1 and examples 4 to 7 were subjected to an atomic force microscope AFM test, a particle size detection, and a fluorescence spectrum test, respectively.
Example 1 the results of AFM measurement and particle size measurement are shown in fig. 1A, 1B and 1C, and the results of fluorescence spectrum measurement are shown in fig. 2. In example 4, results of the atomic force microscope AFM test and the particle size measurement are shown in fig. 11A, 11B, and 11C, and results of the fluorescence spectrum test are shown in fig. 12. In example 5, results of the atomic force microscope AFM test and the particle size measurement are shown in fig. 13A, 13B, and 13C, and results of the fluorescence spectrum test are shown in fig. 14. In example 6, results of the atomic force microscope AFM test and the particle size measurement are shown in fig. 15A, 15B, and 15C, and results of the fluorescence spectrum test are shown in fig. 16. In example 7, results of the atomic force microscope AFM test and the particle size measurement are shown in fig. 17A, 17B, and 17C, and results of the fluorescence spectrum test are shown in fig. 18.
The product prepared in comparative example 1 was subjected to fluorescence spectroscopy. The fluorescence spectrum test results are shown in FIG. 3.
As can be seen from fig. 1A to fig. 1C in combination with fig. 2, the product prepared in example 1 is a nitrogen-doped carbon quantum dot with a significant fluorescence effect, and the maximum fluorescence emission peak of the nitrogen-doped carbon quantum dot is about 444nm, which is consistent with the previously reported fluorescence properties of the nitrogen-doped carbon quantum dot. As can be seen from fig. 11A to 11C in conjunction with fig. 12, the product prepared in example 4 is a nitrogen-doped carbon quantum dot with a distinct fluorescent effect; as can be seen from fig. 13A to 13C in conjunction with fig. 14, the product prepared in example 5 is a nitrogen-doped carbon quantum dot with a distinct fluorescent effect; as can be seen from fig. 15A to 15C in conjunction with fig. 16, the product prepared in example 6 is a nitrogen-doped carbon quantum dot with a distinct fluorescent effect; from fig. 17A to 17C in combination with fig. 18, it can be seen that the product prepared in example 7 is a nitrogen-doped carbon quantum dot with a significant fluorescence effect.
As can be seen from fig. 3, the fluorescence characterization graph of the electrolyte obtained by electrolyzing the pure carbon cloth can find the fluorescence peak of the carbon quantum dot, which indicates that the non-fluorescent carbon quantum dot is generated. The fluorescent carbon quantum dots in the electrolyte obtained by the electrolysis of the coated electrode are basically stripped from the coated nitrogen-doped porous carbon by electrolysis.
Experimental example 2
The iron-nitrogen doped carbon quantum dots prepared in example 2 were subjected to an atomic force microscope AFM test, a particle size detection, and a fluorescence spectrum test, respectively.
The results of the atomic force microscope AFM test and the particle size measurement are shown in fig. 6A, 6B, and 6C, and the results of the fluorescence spectrum measurement are shown in fig. 7. As can be seen from fig. 6A to 6C in combination with fig. 7, the product prepared in example 2 is an iron-nitrogen doped carbon quantum dot with a significant fluorescence effect, and the maximum fluorescence emission peak of the iron-nitrogen doped carbon quantum dot is around 460 nm. Therefore, the carbon quantum dots prepared by using the carbon quantum dots provided by the invention are carbon quantum dots with obvious fluorescence effect.
Experimental example 3
The carbon quantum dots prepared in example 3 were subjected to an atomic force microscope AFM test, a particle size detection, and a fluorescence spectrum test, respectively.
The results of the atomic force microscope AFM test and the particle size detection are shown in fig. 19A, 19B, and 19C, and the results of the fluorescence spectrum test are shown in fig. 20. As can be seen from fig. 19A to 19C and fig. 20, the product prepared in example 3 is a carbon quantum dot with a significant fluorescence effect, and the maximum fluorescence emission peak of the carbon quantum dot is around 465 nm. Therefore, the carbon quantum dots prepared by using the carbon quantum dots provided by the invention are carbon quantum dots with obvious fluorescence effect. It can be seen from experimental examples 1 to 3 that the preparation method of the carbon quantum dot provided by the present application can be applied to the preparation of various carbon quantum dots, whether doped (e.g., experimental examples 1 to 2) or undoped (e.g., experimental example 3) carbon quantum dots, and whether doped with one element (e.g., experimental example 1) or doped with multiple elements (e.g., experimental example 2) carbon quantum dots.
Experimental example 4
The influence of the voltage during electrolysis on the particle size of the prepared carbon quantum dots was tested.
As can be seen from comparison of the particle diameters of the nitrogen-doped carbon quantum dots prepared in comparative examples 1, 5 and 6, i.e., from fig. 1A to 1C, 11A to 11C and 13A to 13C, the average particle diameter of the nitrogen-doped carbon quantum dots was changed from 1.2nm (voltage of 3V) to 3.1nm (voltage of 5V) and finally to 7.1nm (voltage of 7V), and it was found that the particle diameter of the nitrogen-doped carbon quantum dots increased with an increase in voltage.
In the experimental example, the nitrogen-doped carbon quantum dots are prepared by electrolysis under different direct-current voltage conditions within 2-10V, and the fact that the average particle size of the carbon quantum dots is correspondingly increased along with the increase of the voltage is found, so that the carbon quantum dots with the corresponding particle sizes can be prepared by regulating and controlling the voltage.
Experimental example 5
And testing the influence of different binder contents on the particle size of the prepared carbon quantum dots.
As can be seen from comparison of the particle diameters of the nitrogen-doped carbon quantum dots prepared in the comparative examples 1, 6 and 7, i.e., comparison of fig. 1A to 1C, 15A to 15C and 17A to 17C, the particle diameters of the prepared nitrogen-doped carbon quantum dots are influenced by the content of the binder, wherein the ratio of the nitrogen-doped porous carbon to the PTFE binder is 9mg:1 μ L (average particle diameter of 16.8nm), 17mg:3 μ L (average particle diameter of 3.1nm) and 4mg:1 μ L (average particle diameter of 6.5nm), and the change is probably caused by the fact that the ratio of 9mg:1 μ L is small in the content of the binder, the binder is not firm, large particles are liable to fall off along with electrolysis, the electrolysis etching is not sufficient, and when the ratio is 4mg:1 μ L, the content of the binder is high, the overall conductivity of the electrode is influenced by the non-conductivity of the binder itself, the current loss is large, and the particles are electrolyzed, the electrolysis is not deep enough. Therefore, the ratio of 17mg to 3 μ L is better, and the particle size of the electrolyzed particles is the smallest.
The experimental example researches the influence of different binder contents on the particle size of the prepared carbon quantum dots, and finds that the particle size is influenced by the binder content, so that the particle size can be regulated and controlled by different binder contents.
Experimental example 6
The nitrogen-doped carbon quantum dot prepared in example 1 is calibrated at an excitation wavelength of 360nm by using a reference method and using quinine sulfate (QY: 54%) as a standard reference, wherein the fluorescence quantum yield of the nitrogen-doped carbon quantum dot is 10.44%.
The fluorescence quantum yield adopts quinine sulfate (QY is 54 percent) as a standard reference substance, and the quinine sulfate is dispersed in 0.1mol/L H2SO4Preparing a reference sample in the solution (the concentration of quinine sulfate in the reference sample needs to meet the requirement that the initial absorbance of the reference sample is below 0.1), and dispersing a sample to be detected (the nitrogen-doped carbon quantum dots N-CQDs prepared in example 1) into deionized water (the resistivity of the deionized water at 24 ℃ is 18.25M omega)The method comprises the following steps of (1)/cm) preparing a sample to be detected (the concentration of the sample to be detected in the sample to be detected needs to meet the requirement that the initial absorbance of the sample to be detected is below 0.1), then measuring the ultraviolet visible absorption spectrum of a reference sample and the sample to be detected in the sample to be detected, scanning the fluorescence emission peaks of the two substances under the excitation wavelength of 360nm, and integrating to obtain the peak area. The solution equation is as follows:
where Φ represents fluorescence Quantum Yield (QY), K is the slope of a fitted line with emission peak area and absorbance, η represents refractive index, "x" represents the sample, and "st" represents quinine sulfate. For these solutions, all using water as solvent,. etax/η st1, the equation reduces to:
experimental example 7
The nitrogen-doped carbon quantum dots prepared in example 1 were subjected to a fluorescence quenching test and an iron ion test.
The results of the selective fluorescence quenching test of the nitrogen-doped carbon quantum dots on iron ions are shown in FIG. 4, and the results of the iron ion test are shown in FIG. 5, wherein F and F0The fluorescence intensity of the iron-nitrogen doped carbon quantum dots obtained in the presence and absence of metal ions, respectively. As can be seen from FIGS. 4-5, the nitrogen-doped carbon dot can be well used for iron ion detection, has good selectivity to iron ions, and has sensitive response, a large linear detection range (0-1000. mu. mol/L) and an excellent detection limit of 0.8. mu. mol/L.
And (3) calculation of detection limit: the limit of detection (LOD) of iron ions was calculated by the following formula
Wherein sigma is F/F0Value targetQuasi-deviation (i.e. 1.12 x 10)-4) K is F/F0The slope of the linear relationship with the iron ion concentration, i.e., the slope of the linear line in the linear range of iron ion detection, i.e., the slope (excluding the minus sign) in fig. 5 (i.e., 4.21 × 10)-4)。
Experimental example 8
The iron-nitrogen doped carbon quantum dots prepared in example 2 were subjected to a fluorescence quenching test and a copper ion test.
The results of the fluorescence quenching test are shown in FIG. 8, and the results of the iron ion test are shown in FIG. 9, in which F and F0The fluorescence intensity of the iron nitrogen doped carbon quantum dots obtained in the presence and absence of metal ions, respectively. As can be seen from FIGS. 8-9, the nitrogen-doped carbon dots can be well used for copper ion detection, have good selectivity to copper ions, and have sensitive response, large linear detection range (0-500. mu. mol/L) and excellent detection limit of 0.8. mu. mol/L.
Calculation of detection Limit the limit of detection of copper ions (LOD) was calculated by the following formula
Wherein sigma is F/F0Standard deviation of values (i.e. 8.2 × 10)-5) K is F/F0The slope of the linear relationship with the copper ion concentration, i.e. the slope of the linear line in the linear range of copper ion detection, i.e. the slope in fig. 9 (i.e. 3.06 × 10)-4)。
Experimental example 9
The prepared carbon quantum dots prepared in examples 1 to 7 were tested for particle size distribution.
As is clear from fig. 1C, 6C, 11C, 13C, 15C, and 17C, the particle size distribution range of the carbon quantum dots prepared in each example is narrow, and the particle size is uniform. Taking the carbon quantum dots prepared in example 1 as an example, the particle size distribution range is 2.0nm-3.6nm, the particle size distribution range is mainly concentrated between 2.8nm-3.4nm, and the average particle size is 3.1 nm.
Experimental example 10
The nitrogen-doped carbon quantum dots prepared in example 1 were tested and the XPS spectra of the nitrogen-doped porous carbon were expected. The results are shown in FIG. 10.
As shown in fig. 10, the XPS spectra of the nitrogen-doped carbon quantum dot and the raw material nitrogen-doped porous carbon show that the oxygen peak of the nitrogen-doped carbon quantum dot obtained by electrolysis is greatly enhanced compared with that of the prior raw material, which indicates that a large amount of oxygen-containing functional groups are introduced during the electrolysis process, and the nitrogen-doped carbon quantum dot prepared by the oxygen-containing polar functional groups has excellent hydrophilic properties.
In conclusion, the electrode plate prepared by the preparation method of the carbon quantum dots is used for preparing the carbon quantum dots through electrolysis, and has the advantages of simple operation, high electrolysis efficiency, repeatable recycling of the substrate, high yield of the carbon quantum dots, easiness in large-scale production, low cost, controllable particle size, greenness, purity, no impurities, easiness in dissolving in water and the like.
Claims (37)
1. A method for preparing a carbon quantum dot, wherein the method comprises:
1) compounding a carbon material on carbon cloth to prepare an electrode;
2) electrolyzing in electrolyte by taking the electrode as an anode to prepare the carbon quantum dots;
the carbon material includes undoped carbon and doped carbon.
2. The production method according to claim 1, wherein, in the step 1), the carbon material is compounded on the carbon cloth, and the electrode is produced by:
A. dispersing a carbon material and a binder into a solvent to form a dispersion slurry;
B. and coating the dispersion slurry on carbon cloth, and then drying to prepare the electrode.
3. The production method according to claim 2, wherein the solvent includes at least one of ethanol and water.
4. The method of claim 2, wherein the binder comprises at least one of a polytetrafluoroethylene binder, a perfluorosulfonic acid-polytetrafluoroethylene copolymer binder, a phenolic resin, and polyvinylidene fluoride.
5. The method of claim 4, wherein the binder comprises at least one of a polytetrafluoroethylene binder, a perfluorosulfonic acid-polytetrafluoroethylene copolymer binder.
6. The production method according to claim 5, wherein the binder is a polytetrafluoroethylene binder.
7. The production method according to claim 2, wherein the dispersing of the carbon material and the binder into the solvent is carried out by: the carbon material and the binder are added to a solvent and ground, thereby dispersing the carbon material and the binder in the solvent.
8. The method of claim 7, wherein the milling time is not less than 5 min.
9. The production method according to claim 2, wherein the amount ratio of the carbon material to the binder used for compounding the carbon material onto the carbon cloth is 9.5mg:0.5 μ L to 5mg:5 μ L.
10. The production method according to claim 9, wherein the amount ratio of the carbon material to the binder used for compounding the carbon material onto the carbon cloth is 3mg:1 μ L to 19mg:1 μ L.
11. The production method according to claim 10, wherein the amount ratio of the carbon material to the binder used for compounding the carbon material onto the carbon cloth is 4mg:1 μ L to 9mg:1 μ L.
12. The production method according to claim 11, wherein the amount ratio of the carbon material to the binder for compounding the carbon material onto the carbon cloth is 17mg:3 μ L.
13. The method according to claim 1, wherein the amount of the carbon material compounded on the carbon cloth is 2 to 10mg per square centimeter.
14. The method of claim 1, wherein the electrolyte comprises at least one of an aqueous solution of sodium hydroxide in ethanol, aqueous ammonia, and pure water.
15. The production method according to claim 14, wherein the electrolyte is an aqueous solution of sodium hydroxide and ethanol.
16. The production method according to claim 14, wherein the concentration of the sodium hydroxide in the aqueous solution of sodium hydroxide in ethanol is 0.005 to 0.1 mol/L.
17. The method of claim 14, wherein the volume ratio of ethanol to water in the aqueous solution of sodium hydroxide in ethanol is from 3:1 to 5: 1.
18. The method according to claim 14, wherein the water used for preparing the aqueous solution of sodium hydroxide in ethanol is pure water.
19. The production method according to claim 14, wherein the pure water has an electrical resistivity of 18.25M Ω/cm at 24 ℃.
20. The production method according to claim 1, wherein the counter electrode used for electrolysis includes at least one of a graphite rod, a platinum sheet electrode, and a platinum wire electrode.
21. The production method according to claim 20, wherein the counter electrode used for electrolysis is a graphite rod.
22. The production method according to claim 1, wherein a power source used for the electrolysis is a direct current power source.
23. The production method according to claim 1, wherein the voltage used for the electrolysis is 2 to 10V.
24. The production method according to any one of claims 1 to 23, wherein the carbon material includes at least one of undoped carbon, nitrogen-doped carbon, and iron-nitrogen-doped carbon.
25. The production method according to claim 24, wherein the carbon material includes at least one of graphene prepared using graphene oxide and a reducing agent, undoped porous carbon prepared using a carbon source and a template, nitrogen-doped graphene prepared using graphene oxide, a reducing agent and a nitrogen source, nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source and a template, iron-nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source, an iron source and a template.
26. The preparation method according to claim 25, wherein the carbon material includes at least one of graphene prepared using graphene oxide and hydrazine hydrate, undoped porous carbon prepared by calcination using triphenylmethane and a magnesium oxide template, nitrogen-doped graphene prepared using graphene oxide and urea, nitrogen-doped porous carbon prepared by calcination using 1,10 phenanthroline and a magnesium oxide template, and iron-nitrogen-doped porous carbon generated by calcination using 1,10 phenanthroline plus ferric trichloride and a magnesium oxide template.
27. The production method according to claim 24, wherein the carbon material includes at least one of nitrogen-doped carbon and iron-nitrogen-doped carbon.
28. The production method according to claim 27, wherein the carbon material includes at least one of nitrogen-doped graphene, nitrogen-doped porous carbon, iron-nitrogen-doped porous carbon.
29. The preparation method according to claim 28, wherein the carbon material may include at least one of nitrogen-doped graphene prepared using graphene oxide, a reducing agent, and a nitrogen source, nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source, and a template, and iron-nitrogen-doped porous carbon prepared using a carbon source, a nitrogen source, an iron source, and a template.
30. The production method according to claim 29, wherein the carbon material may include nitrogen-doped graphene produced using graphene oxide and urea; the method comprises the steps of calcining the prepared nitrogen-doped porous carbon by using a 1,10 phenanthroline and magnesium oxide template, and calcining the nitrogen-doped porous carbon by using the 1,10 phenanthroline, ferric trichloride and a magnesium oxide template to generate iron-nitrogen-doped porous carbon.
31. A carbon quantum dot produced by the method for producing a carbon quantum dot according to any one of claims 27 to 30; the carbon quantum dots are nitrogen-doped carbon quantum dots or iron-nitrogen-doped carbon quantum dots.
32. The use of the carbon quantum dot of claim 31 in iron ion detection, wherein the carbon quantum dot is a nitrogen-doped carbon quantum dot.
33. The use of claim 32, wherein the linear detection range of the detection is 0 μmol/L to 1000 μmol/L.
34. The use of claim 32, wherein the limit of detection of said detection is 0.8 μmol/L.
35. The use of the carbon quantum dot of claim 31 in copper ion detection, wherein the carbon quantum dot is an iron-nitrogen doped carbon quantum dot.
36. The use of claim 35, wherein the linear detection range of the detection is 0 μmol/L to 500 μmol/L.
37. The use of claim 35, wherein the limit of detection of said detection is 0.8 μmol/L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910772740.XA CN112408362B (en) | 2019-08-21 | 2019-08-21 | Carbon quantum dot and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910772740.XA CN112408362B (en) | 2019-08-21 | 2019-08-21 | Carbon quantum dot and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112408362A CN112408362A (en) | 2021-02-26 |
| CN112408362B true CN112408362B (en) | 2022-07-19 |
Family
ID=74780044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910772740.XA Active CN112408362B (en) | 2019-08-21 | 2019-08-21 | Carbon quantum dot and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112408362B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113201335B (en) * | 2021-05-13 | 2022-07-05 | 江南大学 | Enhanced fluorescent carbon dot, preparation method and application in cadmium ion detection |
| CN114256420B (en) * | 2021-12-24 | 2022-08-30 | 华荣照明有限公司 | Preparation method of carbon quantum dot, carbon quantum dot and application of carbon quantum dot in OLED |
| CN115849339B (en) * | 2022-10-11 | 2024-01-26 | 云南师范大学 | Preparation method of phenanthrene Luo Lintan quantum dot polar fluorescent probe |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015011726A1 (en) * | 2013-07-23 | 2015-01-29 | Council Of Scientific & Industrial Research | Conducting carbon cloth electrode for hydrogen generation and dye sensitized solar cells |
| CN105733573B (en) * | 2015-09-24 | 2018-11-06 | 中国石油大学(华东) | Electrolysis nitrating one-step method prepares petroleum coke base carbon quantum dot |
| CN106947475B (en) * | 2017-03-30 | 2020-01-10 | 皖西学院 | Preparation method of fluorescent carbon quantum dots and detection of Al in water by using fluorescent carbon quantum dots3+Ion application |
| CN108251108B (en) * | 2018-01-19 | 2020-12-08 | 北京服装学院 | Preparation of iron ion doped carbon quantum dot, obtained carbon quantum dot and application |
-
2019
- 2019-08-21 CN CN201910772740.XA patent/CN112408362B/en active Active
Non-Patent Citations (2)
| Title |
|---|
| Water-Soluble Fluorescent Carbon Quantum Dots and Photocatalyst;Haitao Li，et al.;《Angew. Chem. Int. Ed》;20100609;全文 * |
| 基于碳量子点荧光猝灭-恢复法测定L-半胱氨酸;刘梦琴，等;《衡阳师范学院学报》;20171215;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112408362A (en) | 2021-02-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112408362B (en) | Carbon quantum dot and preparation method and application thereof | |
| KR101835879B1 (en) | Process for preparation of nanoporous graphene and graphene quantum dots | |
| US7998450B2 (en) | Continuous methods and apparatus of functionalizing carbon nanotube | |
| Ejigu et al. | On the role of transition metal salts during electrochemical exfoliation of graphite: antioxidants or metal oxide decorators for energy storage applications | |
| CN108779562B (en) | Metal doped tin oxide for electrocatalytic applications | |
| CN114620815A (en) | Device and method for electro-Fenton process using carbon electrodes and use thereof for removing organic pollutants | |
| CN105733573B (en) | Electrolysis nitrating one-step method prepares petroleum coke base carbon quantum dot | |
| TW201924949A (en) | Energy storage devices, membrane thereof and ink for printed film | |
| CN108190877B (en) | Graphene oxide, preparation method and application | |
| CN103253740A (en) | Preparation method of three-dimensional hierarchical graphene/porous carbon composite capacitive type desalination electrode | |
| Zhu et al. | Performance improvement of N-doped carbon ORR catalyst via large through-hole structure | |
| Hsieh et al. | Photoluminescence from amino functionalized graphene quantum dots prepared by electrochemical exfoliation method in the presence of ammonium ions | |
| WO2007049549A1 (en) | Method for producing fine particles of salt, hydroxide or oxide, and fine particles of salt, hydroxide or oxide produced by such method | |
| CN111606317A (en) | Nano fluorescent carbon dots and preparation method thereof | |
| Peng et al. | N-Doped ordered mesoporous carbon grafted onto activated carbon fibre composites with enhanced activity for the electro-Fenton degradation of Brilliant Red X3B dye | |
| FR2466436A1 (en) | PROCESS FOR PREPARING GEL AND SILICA XEROGEL AND SILICA XEROGEL OBTAINED | |
| CN108191008B (en) | Preparation method and application of Pd/TiN electro-catalytic electrode | |
| JP6634339B2 (en) | Oxygen reduction catalyst and method for producing the same | |
| JP6762417B2 (en) | Manufacturing method and application of graphite-like microcrystalline carbon nanomaterials | |
| Piri et al. | In situ one‐pot electrochemical synthesis of aluminum oxide/polyaniline nanocomposite; characterization and its adsorption properties towards some heavy metal ions | |
| CN108277520A (en) | The preparation method of hollow cube stannous chloride film | |
| WO2020092473A1 (en) | Composite films and methods of making and use thereof | |
| KR102029539B1 (en) | Method of manufacturing electrode for water treatment | |
| Mirzaie et al. | Non-enzymatic reusable graphene-based electrodes by a simple scalable preparation method and superior electrochemical property | |
| JP6815918B2 (en) | Silver acetylide and its manufacturing method |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |