CN112048297B - Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof - Google Patents
Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof Download PDFInfo
- Publication number
- CN112048297B CN112048297B CN202010949585.7A CN202010949585A CN112048297B CN 112048297 B CN112048297 B CN 112048297B CN 202010949585 A CN202010949585 A CN 202010949585A CN 112048297 B CN112048297 B CN 112048297B
- Authority
- CN
- China
- Prior art keywords
- carbon quantum
- quantum dot
- titanium dioxide
- carbon
- phenylenediamine
- 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
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 141
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 95
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 48
- 239000002131 composite material Substances 0.000 title claims abstract description 46
- 239000004408 titanium dioxide Substances 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 37
- 238000006243 chemical reaction Methods 0.000 claims abstract description 50
- GEYOCULIXLDCMW-UHFFFAOYSA-N 1,2-phenylenediamine Chemical compound NC1=CC=CC=C1N GEYOCULIXLDCMW-UHFFFAOYSA-N 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 26
- 238000001027 hydrothermal synthesis Methods 0.000 claims abstract description 19
- 238000002156 mixing Methods 0.000 claims abstract description 12
- WHUUTDBJXJRKMK-VKHMYHEASA-N L-glutamic acid Chemical compound OC(=O)[C@@H](N)CCC(O)=O WHUUTDBJXJRKMK-VKHMYHEASA-N 0.000 claims description 55
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical group NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 claims description 30
- 229940018564 m-phenylenediamine Drugs 0.000 claims description 30
- 229960002989 glutamic acid Drugs 0.000 claims description 28
- 239000011550 stock solution Substances 0.000 claims description 14
- 230000035484 reaction time Effects 0.000 claims description 11
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 238000004108 freeze drying Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims 10
- 125000003338 L-glutaminyl group Chemical group O=C([*])[C@](N([H])[H])([H])C([H])([H])C([H])([H])C(=O)N([H])[H] 0.000 claims 1
- 230000001699 photocatalysis Effects 0.000 abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 20
- 238000013329 compounding Methods 0.000 abstract description 10
- 229910001868 water Inorganic materials 0.000 abstract description 9
- 239000000463 material Substances 0.000 abstract description 8
- 238000011065 in-situ storage Methods 0.000 abstract description 7
- 238000000746 purification Methods 0.000 abstract description 7
- 230000004048 modification Effects 0.000 abstract description 4
- 238000012986 modification Methods 0.000 abstract description 4
- 238000005580 one pot reaction Methods 0.000 abstract description 4
- 238000002161 passivation Methods 0.000 abstract description 4
- RWSXRVCMGQZWBV-WDSKDSINSA-N glutathione Chemical compound OC(=O)[C@@H](N)CCC(=O)N[C@@H](CS)C(=O)NCC(O)=O RWSXRVCMGQZWBV-WDSKDSINSA-N 0.000 description 35
- STZCRXQWRGQSJD-GEEYTBSJSA-M methyl orange Chemical compound [Na+].C1=CC(N(C)C)=CC=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-GEEYTBSJSA-M 0.000 description 24
- 229940012189 methyl orange Drugs 0.000 description 24
- 102100028892 Cardiotrophin-1 Human genes 0.000 description 18
- 108010041776 cardiotrophin 1 Proteins 0.000 description 18
- 230000005284 excitation Effects 0.000 description 18
- 230000015556 catabolic process Effects 0.000 description 17
- 238000006731 degradation reaction Methods 0.000 description 17
- 239000002096 quantum dot Substances 0.000 description 17
- 238000012360 testing method Methods 0.000 description 17
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 17
- 229960003180 glutathione Drugs 0.000 description 16
- 238000007146 photocatalysis Methods 0.000 description 14
- 239000000243 solution Substances 0.000 description 14
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 13
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 description 12
- 239000008367 deionised water Substances 0.000 description 11
- 229910021641 deionized water Inorganic materials 0.000 description 11
- 239000002994 raw material Substances 0.000 description 10
- 238000000295 emission spectrum Methods 0.000 description 9
- 239000002086 nanomaterial Substances 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 229910052724 xenon Inorganic materials 0.000 description 7
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 7
- YASYEJJMZJALEJ-UHFFFAOYSA-N Citric acid monohydrate Chemical compound O.OC(=O)CC(O)(C(O)=O)CC(O)=O YASYEJJMZJALEJ-UHFFFAOYSA-N 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- 229960002303 citric acid monohydrate Drugs 0.000 description 6
- 238000013033 photocatalytic degradation reaction Methods 0.000 description 6
- 238000011282 treatment Methods 0.000 description 6
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 238000003760 magnetic stirring Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000003917 TEM image Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 229910021642 ultra pure water Inorganic materials 0.000 description 4
- 239000012498 ultrapure water Substances 0.000 description 4
- 108010024636 Glutathione Proteins 0.000 description 3
- 238000003763 carbonization Methods 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000005424 photoluminescence Methods 0.000 description 3
- -1 polytetrafluoroethylene Polymers 0.000 description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 239000004809 Teflon Substances 0.000 description 2
- 229920006362 Teflon® Polymers 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 125000003277 amino group Chemical group 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000002189 fluorescence spectrum Methods 0.000 description 2
- 239000008098 formaldehyde solution Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000002114 nanocomposite Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000011941 photocatalyst Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000006862 quantum yield reaction Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 2
- 238000005917 acylation reaction Methods 0.000 description 1
- 238000012863 analytical testing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012984 biological imaging Methods 0.000 description 1
- UHYPYGJEEGLRJD-UHFFFAOYSA-N cadmium(2+);selenium(2-) Chemical class [Se-2].[Cd+2] UHYPYGJEEGLRJD-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000000608 laser ablation Methods 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 150000004986 phenylenediamines Chemical class 0.000 description 1
- 238000007539 photo-oxidation reaction Methods 0.000 description 1
- 238000001782 photodegradation Methods 0.000 description 1
- 238000000103 photoluminescence spectrum Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Images
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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/063—Titanium; Oxides or hydroxides thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/24—Nitrogen compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
- B01J35/39—Photocatalytic properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
- B01J37/10—Heat treatment in the presence of water, e.g. steam
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
- C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
-
- 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
- C09K11/0883—Arsenides; Nitrides; Phosphides
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/308—Dyes; Colorants; Fluorescent agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/34—Organic compounds containing oxygen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/38—Organic compounds containing nitrogen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/40—Organic compounds containing sulfur
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/10—Photocatalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Nanotechnology (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Manufacturing & Machinery (AREA)
- Biophysics (AREA)
- Optics & Photonics (AREA)
- Composite Materials (AREA)
- Thermal Sciences (AREA)
- Catalysts (AREA)
Abstract
The invention discloses a carbon quantum dot, a carbon quantum dot-titanium dioxide composite material and a preparation method thereof, and relates to the technical field of photocatalytic materials. The preparation method of the carbon quantum dot comprises the following steps: mixing and dissolving a carbon source, phenylenediamine and water, and then carrying out hydrothermal reaction. The method avoids complex purification steps caused by passivation or surface modification, is a simple one-pot method for preparing N-CQDs, and the prepared N-doped carbon quantum dots have good up-conversion fluorescence properties and fluorescence stability. The preparation method of the carbon quantum dot-titanium dioxide composite material adopts an in-situ compounding or later-stage compounding mode, can obviously improve the photocatalytic capacity of titanium dioxide, and has good application prospect.
Description
Technical Field
The invention relates to the technical field of photocatalytic materials, in particular to a carbon quantum dot, a carbon quantum dot-titanium dioxide composite material and a preparation method thereof.
Background
Semiconductor Quantum Dots (QDs) have unique size-dependent photoelectric properties, leading to extensive research into their applications. For example, CdSe quantum dots have applications in sensing, imaging, environmental monitoring, solar cells, and the like. Carbon Quantum Dots (CQDs) are an emerging material that have been used in a variety of applications, such as analytical testing, photocatalysis, etc., due to their excellent biocompatibility, resistance to photodegradation, and low toxicity.
Many methods for preparing Carbon Quantum Dots (CQDs) have been reported, such as laser ablation, electrochemistry, chemical oxidation, etc., some of which require strict reaction conditions and time-consuming purification processes, and the quantum yield of the obtained quantum dots is low. Similar to other nanomaterials, doping heteroatoms into CQDs can create defect levels, alter charge transfer and tune device performance. Among them, N doping has attracted considerable attention because introduction of N atoms can improve quantum yield and efficiently transfer electrons. In recent years, N-doped carbon quantum dots have been prepared by various strategies, which exhibit unique properties such as electrocatalytic activity, tunable luminescence and biocompatibility. This makes N-doped carbon quantum dots show great potential in photocatalysis, analytical detection and biological imaging.
However, many chemical methods for doping N require further passivation or surface modification, which can lead to complicated purification steps and environmental hazards.
Disclosure of Invention
The invention aims to provide a preparation method of a carbon quantum dot, and aims to prepare an N-doped carbon quantum dot with up-conversion fluorescence by a one-step method, and the N-doped carbon quantum dot has good fluorescence performance.
The second purpose of the invention is to provide a carbon quantum dot which is low in preparation cost and has good up-conversion fluorescence property and fluorescence stability.
The third purpose of the invention is to provide a preparation method of the carbon quantum dot-titanium dioxide composite material, aiming at improving the photocatalytic capacity of titanium dioxide.
The fourth object of the present invention is to provide a carbon quantum dot-titanium dioxide composite material having excellent photocatalytic performance.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
The invention provides a preparation method of a carbon quantum dot, which comprises the following steps: and carrying out hydrothermal reaction on a carbon source and a phenylenediamine aqueous solution to obtain a carbon quantum dot stock solution.
The invention provides a carbon quantum dot prepared by the preparation method.
The invention provides a preparation method of a carbon quantum dot-titanium dioxide composite material, which adopts the preparation method and adds titanium dioxide in the stage of mixing raw materials.
The invention provides a preparation method of a carbon quantum dot-titanium dioxide composite material, which comprises the following steps: the preparation method is adopted to prepare the carbon quantum dot stock solution, and then the carbon quantum dot stock solution and the titanium dioxide are mixed and react.
The invention provides a carbon quantum dot-titanium dioxide composite material which is prepared by adopting the preparation method.
The embodiment of the invention provides a preparation method of carbon quantum dots, which has the beneficial effects that: the inventor finds that the N-doped carbon quantum dots can be prepared by a one-step hydrothermal method by using a carbon source, phenylenediamine and water as raw materials, avoids complex purification steps caused by passivation or surface modification, is a simple one-pot method for preparing N-CQDs, and has good up-conversion fluorescence property and fluorescence stability.
The embodiment of the invention also provides a carbon quantum dot which is prepared by the one-pot method, has good water solubility and relatively uniform particle size, and also has excitation wavelength dependence, good up-conversion fluorescence property and fluorescence stability.
The embodiment of the invention also provides a preparation method of the carbon quantum dot-titanium dioxide composite material, which is used for carrying out in-situ compounding by a one-step hydrothermal method or preparing CQDs-TiO by a later-stage compounding method2The composite nano material can obviously improve the photocatalysis capability of the titanium dioxide.
The embodiment of the invention also provides a carbon quantum dot-titanium dioxide composite material which has very good photocatalytic efficiency and very good application prospect.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is CQDs-TiO2The composite material is synthesized schematically by a hydrothermal method;
FIG. 2 shows fluorescence emission spectra of different phenylenediamine-doped carbon quantum dots;
FIG. 3 is a bar graph of the emission spectrum and fluorescence intensity of fluorescent carbon quantum dots at different reaction temperatures;
FIG. 4 is a graph showing emission spectra and fluorescence intensity curves at different reaction times;
FIG. 5 is a transmission electron micrograph of a CQD;
FIG. 6 is a TEM image of CT-1 of example 19;
FIG. 7 is a graph showing the results of fluorescence stability tests of carbon quantum dots;
FIG. 8 shows emission spectra of carbon quantum dots under ultraviolet and visible light excitation;
FIG. 9 is a degradation curve under UV lamp illumination;
FIG. 10 is a degradation curve under simulated sunlight;
FIG. 11 is a graph showing the degradation curve of CT-1 to methyl orange under different light source irradiation;
FIG. 12 shows the photocatalytic activity of CT-1 and CT-0 prepared in different ways on methyl orange under the irradiation of a light source of 600 nm;
FIG. 13 is a line fitted to the degradation curve of CT-1 to formalin solution under UV irradiation and the first order kinetic curve;
fig. 14 is an emission spectrum under ultraviolet and visible light excitation of the carbon quantum dots prepared in the test comparative example.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The fluorescent carbon quantum dot, the fluorescent carbon quantum dot-titanium dioxide composite material and the preparation method thereof provided by the embodiment of the invention are specifically described below.
The embodiment of the invention provides a preparation method of carbon quantum dots, which comprises the following steps: mixing and dissolving a carbon source, phenylenediamine and water, and then carrying out hydrothermal reaction. The inventor finds that the N-doped carbon quantum dot can be prepared by a one-step hydrothermal method by using a carbon source, phenylenediamine and water as raw materials, and the prepared carbon quantum dot has good fluorescence performance.
Specifically, the phenylenediamine is selected from at least one of o-phenylenediamine, m-phenylenediamine and p-phenylenediamine; m-phenylenediamine is preferred. When the m-phenylenediamine is used for regulating and controlling the surface groups of the fluorescent carbon dots, the fluorescence property of the quantum dots is optimal, probably because in the hydrothermal process, two amino groups on the m-phenylenediamine are easier to perform acylation reaction with two carboxyl groups of L-glutamic acid, and then carbonization is performed to form a carbon core.
Specifically, the carbon source is selected from at least one of L-glutamic acid or a derivative thereof, and more preferably L-glutamic acid. The L-glutamic acid is used as a carbon source, so that the cost is low, and the fluorescence property of the prepared carbon quantum dot is excellent.
Further, the hydrothermal reaction temperature is 140-250 ℃, preferably 180-220 ℃, and more preferably 200-220 ℃; the reaction time is 2 to 12 hours, preferably 4 to 8 hours, more preferably 5.5 to 6.5 hours. By optimizing the reaction temperature and the reaction time, the fluorescence property of the N-doped carbon quantum dot can be further improved. The fluorescence of the carbon quantum dots prepared at the reaction temperature is not strong, probably because the incomplete carbonization of the L-glutamic acid causes low-carbonized or non-carbonized molecules around the carbon core; the fluorescent property is not further improved when the reaction temperature is too high. Too long or too short a reaction time may decrease the fluorescence intensity of the carbon quantum dots.
Further, the molar ratio of the carbon source to the phenylenediamine is 1:0.8 to 1.2, preferably 1:0.9 to 1.1. The dosage of the carbon source and the phenylenediamine is controlled to be about 1:1, so that the obtained N-doped quantum dot has good fluorescence property.
The embodiment of the invention also provides a carbon quantum dot which is prepared by the one-step hydrothermal method, the method is simple and easy to implement, and the fluorescence property of the N-doped carbon quantum dot is further improved by optimizing the selection of raw materials, the reaction temperature and the reaction time. The prepared carbon quantum dot has good water solubility and relatively uniform particle size, and also has excitation wavelength dependence, good up-conversion fluorescence property and fluorescence stability.
Referring to fig. 1, an embodiment of the present invention further provides a method for preparing a carbon quantum dot-titanium dioxide composite material, which adopts the above one-step hydrothermal preparation method, and titanium dioxide is added at the raw material mixing stage, i.e., an in-situ compounding method is used to prepare CQDs-TiO2A composite nanomaterial. CQDs/TiO prepared by simple hydrothermal method2Mainly has anatase structure, and carbon quantum dots can not be aligned with TiO in hydrothermal process2The crystal form causes influence. After the up-conversion fluorescent carbon quantum dots are combined with the up-conversion fluorescent carbon quantum dots to prepare the composite material, the photocatalytic capability can be effectively improved under ultraviolet light or visible light.
In some embodiments, after the reaction is complete, freeze-drying is performed to obtain a powder of the composite material.
Additionally, CQDs/TiO2The material can perform photocatalysis by utilizing the up-conversion property of the fluorescent carbon quantum dot, and can convert long-wavelength light into ultraviolet light (300-400nm) with short wavelength and high energy by the up-conversion effect, thereby exciting TiO2So that the methyl orange is degraded. Can achieve the photocatalysis effect close to that under the irradiation of a 3W ultraviolet lamp (365nm) under the irradiation of 3W monochromatic light (600 nm). CQDs/TiO2The composite nano material has stronger purification effect on formaldehyde, and can be degraded by half in 480min photocatalysis even in the presence of formaldehyde with higher concentrationThe above.
The embodiment of the invention also provides a preparation method of the carbon quantum dot-titanium dioxide composite material, which comprises the following steps: preparing a carbon quantum dot stock solution by adopting the one-step hydrothermal preparation method, mixing the carbon quantum dot stock solution and titanium dioxide for reaction, namely preparing CQDs-TiO by adopting a later-stage compounding method2A composite nanomaterial.
In the preparation methods of the two carbon quantum dot-titanium dioxide composite materials, the molar ratio of the carbon source to the titanium dioxide is 1:1-100, and preferably 1: 1-2. The inventor finds that the photocatalytic activity is best when the molar ratio of the carbon source to the titanium dioxide is controlled to be 1: 1-2.
Preferably, the carbon quantum dot stock solution and the titanium dioxide are mixed and reacted for 20 to 30 hours under the condition of keeping out of the sun; in some embodiments, freeze-drying is performed after the reaction of the carbon quantum dot dope and titanium dioxide is completed to obtain a powder of the composite material.
The embodiment of the invention also provides a carbon quantum dot-titanium dioxide composite material which is prepared by adopting the in-situ compounding or later-stage compounding method, and has very good photocatalytic efficiency and very good application prospect.
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
The embodiment provides a preparation method of a carbon quantum dot, which comprises the following steps:
0.74g (0.005mol) of L-glutamic acid and 0.054g (0.0005mol) of o-phenylenediamine were weighed into a 50mL polytetrafluoroethylene reaction vessel, and dissolved in 20mL of deionized water. After magnetic stirring for 30min, the stirrer is taken out and reacted in an oven at 200 ℃ for 6 h. And after the reaction is finished, cooling the mixture to room temperature along with an oven, and taking out the carbon quantum dot stock solution.
Example 2
This example provides a method for preparing carbon quantum dots, which is different from example 1 only in that: the o-phenylenediamine is replaced by equimolar m-phenylenediamine.
Example 3
This example provides a method for preparing carbon quantum dots, which is different from example 1 only in that: the o-phenylenediamine is replaced by an equimolar amount of p-phenylenediamine.
Example 4
The embodiment provides a preparation method of a carbon quantum dot, which comprises the following steps:
3.7g L-glutamic acid and 0.27g m-phenylenediamine were weighed into a polytetrafluoroethylene reaction vessel and dissolved in 100mL of deionized water. After magnetic stirring for 30min, the stirrer is taken out and reacted in an oven at 140 ℃ for 6 h. And after the reaction is finished, cooling the mixture to room temperature along with an oven, and taking out the carbon quantum dot stock solution.
Examples 5 to 8
This example provides a method for preparing carbon quantum dots, and examples 5 to 8 are different from example 4 only in that: the reaction temperature is 160 ℃, 180 ℃, 200 ℃ and 220 ℃ in sequence.
Example 9
The embodiment provides a preparation method of a carbon quantum dot, which comprises the following steps:
4.44g L-glutamic acid and 0.324g m-phenylenediamine were weighed into a polytetrafluoroethylene reaction vessel and dissolved in 120mL of deionized water. After magnetic stirring for 30min, the stirrer is taken out and reacted in an oven at 200 ℃ for 2 h. And after the reaction is finished, cooling the mixture to room temperature along with an oven, and taking out the carbon quantum dot stock solution.
Examples 10 to 14
This example provides a method for preparing carbon quantum dots, and examples 10 to 14 differ from example 9 only in that: the reaction time is 4h, 6h, 8h, 10h and 12h in sequence.
Example 15
The embodiment provides a preparation method of a carbon quantum dot-titanium dioxide composite material, which comprises the following steps:
mixing L-glutamic acid (0.0368g,0.00025mol), m-phenylenediamine (0.0027g,0.000025mol) and TiO2(1.9975g,0.025mol) was dissolved in 100mL of deionized water. After magnetic stirring for 30min, the solution was transferred to a 250mL Teflon reaction kettle and placed in an oven at 200 ℃ for 6 h. After the reaction was completed, the reaction product was taken out with oven cooling to room temperature, and CT-100 (in terms of molar ratio, L-glutamic acid: TiO2 ═ 1:100) solution was obtained. Then, the obtained solution is mixedFreeze drying to obtain CT-100 powder.
Examples 16 to 19
This example provides a method for preparing a carbon quantum dot-titanium dioxide composite material, which is different from example 15 only in that: l-glutamic acid and TiO2The molar ratio of (A) is as follows:
example 16: CT-20 (L-glutamic acid: TiO)21: 20): mixing L-glutamic acid (0.1839g,0.00125mol), m-phenylenediamine (0.0135g,0.000125mol) and TiO2(1.9975g,0.025mol) was dissolved in 100mL of deionized water and the subsequent treatments were as above.
Example 17: CT-10 (L-glutamic acid: TiO)21: 10): mixing L-glutamic acid (0.3678g,0.0025mol), m-phenylenediamine (0.0270g,0.00025mol) and TiO2(1.9975g,0.025mol) was dissolved in 100mL of deionized water and the subsequent treatments were as above.
Example 18: CT-2 (L-glutamic acid: TiO)21: 2): mixing L-glutamic acid (1.8391g,0.0125mol), m-phenylenediamine (0.1352g,0.00125mol) and TiO2(1.9975g,0.025mol) was dissolved in 100mL of deionized water and the subsequent treatments were as above.
Example 19: CT-1 (L-glutamic acid: TiO)21: 1): mixing L-glutamic acid (3.67825g,0.025mol), m-phenylenediamine (0.27035g,0.0025mol) and TiO2(1.9975g,0.025mol) was dissolved in 100mL of deionized water and the subsequent treatments were as above.
Example 20
The embodiment provides a preparation method of a carbon quantum dot-titanium dioxide composite material, which comprises the following steps: CT-0 (L-glutamic acid: TiO)21: 1): l-glutamic acid (3.67825g,0.025mol) and m-phenylenediamine (0.27035g,0.0025mol) were dissolved in 100mL of deionized water. After magnetic stirring for 30min, the solution was transferred to a 250mL Teflon reaction kettle and placed in an oven at 200 ℃ for 6 h. And after the reaction is finished, cooling the reaction product to room temperature along with an oven, and taking out the reaction product to obtain the carbon quantum dot solution. Then, TiO was added to the resulting solution2(1.9975g,0.025mol), stirred magnetically for 24h in the absence of light. Thereafter, the suspension was freeze-dried to obtain CT-0 powder.
Comparative example 1
The comparative example provides a preparation method of a carbon quantum dot, which adopts the existing preparation method and specifically comprises the following steps: reduced glutathione (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of ethanol and transferred to an autoclave, reacted in an oven at 200 ℃ for 6 hours, and the subsequent treatments were the same as in example 1.
Comparative example 2
The comparative example provides a preparation method of a carbon quantum dot, which adopts the existing preparation method and specifically comprises the following steps: citric acid monohydrate (2.1014g, 0.01mol) and m-phenylenediamine (0.108g, 0.001mol) were dissolved in 20mL of ultrapure water and transferred to an autoclave, reacted in an oven at 180 ℃ for 6 hours, and the subsequent treatments were the same as in example 1.
Comparative example 3
The comparative example uses reduced glutathione (GSH, C10H17N3O6S, 307.32g/mol) and O-phenylenediamine (C6H8N2, 108.1426g/mol) as raw materials to prepare the carbon dots, and comprises the following groups:
(1) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of formamide and transferred to an autoclave for 6 hours in an oven at 210 ℃.
(2) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 21mL of a DMF: formamide (1: 6) mixture and transferred to an autoclave for reaction in an oven at 210 ℃ for 6 hours.
(3) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of a DMF: formamide (3: 2) mixture and transferred to an autoclave for reaction in an oven at 210 ℃ for 6 hours.
(4) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL DMF and transferred to an autoclave for 6 hours in an oven at 210 ℃.
(5) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of ethanol and transferred to an autoclave for 6 hours in an oven at 210 ℃.
(6) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of an aqueous sulfuric acid solution (2.8mol/L) and transferred to an autoclave for 6 hours in an oven at 210 ℃.
(7) GSH (0.154g, 0.0005mol) and o-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of an aqueous sulfuric acid solution (6.1mol/L) and transferred to an autoclave for reaction in an oven at 210 ℃ for 6 hours.
Comparative example 4
The comparative example takes reduced glutathione (GSH, C10H17N3O6S, 307.32g/mol) and m-phenylenediamine (C6H8N2, 108.1426g/mol) as raw materials to prepare the carbon dots, and specifically comprises the following groups:
(1) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of formamide and transferred to an autoclave for 6 hours in an oven at 200 ℃.
(2) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 21mL of a DMF: formamide (1: 6) mixture and transferred to an autoclave for reaction in an oven at 200 ℃ for 6 hours.
(3) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of a DMF: formamide (3: 2) mixture and transferred to an autoclave for reaction in an oven at 200 ℃ for 6 hours.
(4) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of DMF and transferred to an autoclave for reaction in an oven at 200 ℃ for 6 hours.
(5) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of ethanol and transferred to an autoclave for reaction in an oven at 200 ℃ for 6 hours.
(6) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of an aqueous sulfuric acid solution (2.8mol/L) and transferred to an autoclave, and reacted in an oven at 200 ℃ for 6 hours.
(7) GSH (0.154g, 0.0005mol) and m-phenylenediamine (0.162g, 0.0015mol) were dissolved in 20mL of an aqueous sulfuric acid solution (6.1mol/L) and transferred to an autoclave, and reacted in an oven at 200 ℃ for 6 hours.
Comparative example 5
The carbon dots are prepared by using citric acid monohydrate (CA, C6H8O 7. H2O, 210.14g/mol) and phenylenediamine (C6H8N2, 108.1426g/mol) as raw materials, and specifically comprise the following groups:
(1) CA (2.1014g, 0.01mol) and o-phenylenediamine (0.108g, 0.001mol) were dissolved in 20mL of ultrapure water and transferred to an autoclave for 6 hours in an oven at 180 ℃.
(2) CA (2.1014g, 0.01mol) and m-phenylenediamine (0.108g, 0.001mol) were dissolved in 20mL of ultrapure water and transferred to an autoclave for 6 hours in an oven at 180 ℃.
(3) CA (2.1014g, 0.01mol) and p-phenylenediamine (0.108g, 0.001mol) were dissolved in 20mL of ultrapure water and transferred to an autoclave for 6 hours in an oven at 180 ℃.
Test example 1
The fluorescence properties of the carbon quantum dots prepared in examples 1 to 3 were tested, and FIG. 2 shows fluorescence emission spectra (410nm excitation) of carbon quantum dots prepared from different phenylenediamines and L-glutamic acid.
As can be seen from FIG. 2, the strongest emission wavelength of the carbon quantum dots is 510nm, and the fluorescence performance of the quantum dots is the best when the m-phenylenediamine is adopted to regulate and control the surface groups of the fluorescent carbon dots; when the o-phenylenediamine is adopted to regulate and control the surface groups of the fluorescent carbon dots, the fluorescence performance of the quantum dots is reduced; and when the surface groups of the fluorescent carbon dots are regulated and controlled by adopting p-phenylenediamine, the fluorescence property of the quantum dots is the worst. This is probably because two amino groups on m-phenylenediamine are more likely to be acylated with two carboxyl groups of L-glutamic acid during hydrothermal treatment, and are carbonized to form a carbon core.
Test example 2
The fluorescence properties of the carbon quantum dots prepared in examples 4 to 8 were tested, and fig. 3 shows emission spectra (410nm excitation) of the fluorescent carbon quantum dots at different reaction temperatures.
As can be seen from FIG. 3, the fluorescence emission peak has symmetrical peak shape, which indicates that the particle size of the quantum dots is relatively uniform. In addition, the fluorescence intensity of the carbon quantum dots increases with the increase in the reaction temperature. When the reaction temperature is increased from 140 ℃ to 160 ℃, the fluorescence emission peak intensity of the carbon quantum dots is less improved; when the reaction temperature is increased to 180 ℃, the peak intensity is obviously increased; when the temperature was increased to 200 ℃ and 220 ℃, the peak intensity was not significantly increased. The fluorescence of the carbon quantum dots prepared at the lower reaction temperature is not strong, probably because incomplete carbonization of L-glutamic acid results in low-carbonized or non-carbonized molecules around the carbon core. Therefore, in the aspect of energy conservation, the optimal temperature for controlling the surface groups of the carbon quantum dots by the m-phenylenediamine is 200-220 ℃ by taking the L-glutamic acid as a carbon source.
Test example 3
The fluorescence properties of the carbon quantum dots prepared in examples 9 to 14 were tested, and fig. 4 is an emission spectrum (410nm) of the fluorescent carbon quantum dots at different reaction times.
As can be seen from fig. 4, the fluorescence intensity of the carbon quantum dots tended to increase and then decrease. When the reaction time is increased from 2h to 6h, the fluorescence intensity of the carbon quantum dots is gradually increased. When the hydrothermal time is 6h, the fluorescence of the quantum dots is strongest. Thereafter, the fluorescence intensity starts to decrease. This may cause oxidation of carbon atoms on the surface of the quantum dot due to too long reaction time, so that non-radiative recombination centers increase, and the luminous intensity of the carbon quantum dot is reduced. In addition, the reaction time is too long, the particle size of the carbon dots begins to increase, and the concentration of the carbon dots also increases, which may cause self-absorption of the carbon quantum dots and fluorescence quenching. Therefore, L-glutamic acid is used as a carbon source, m-phenylenediamine is used for regulating and controlling surface groups of the fluorescent carbon dots, the carbon quantum dots prepared by the hydrothermal reaction for 4-8h have good fluorescent property, and the effect of the hydrothermal reaction for 6h is optimal.
Test example 4
Transmission electron micrographs of the carbon quantum dots prepared in test example 1 (a) are low-resolution images and (b) are high-resolution images, and the results are shown in fig. 5. Meanwhile, the TEM image of CT-1 in test example 19 is shown in FIG. 6.
In fig. 5, (a) is a low resolution graph showing approximately that the carbon quantum dots are well dispersed in deionized water and have relatively uniform particle sizes. It was also shown that there were bubbles in the sample and a partial aggregation phenomenon in the vicinity of the bubbles, which is probably due to aggregation of carbon quantum dots having a large number of hydrophilic functional groups due to surface tension. (b) For the high resolution plot, it is clearly shown that the prepared quantum dots are spherical in shape with a diameter size of about 10nm and no other quantum dots are aggregated around, again demonstrating good dispersion of the carbon quantum dots in deionized water.
As can be seen in fig. 6: CT-1 is spherical and has an average diameter of about 25 nm.
The stability of the fluorescent carbon quantum dots of the product prepared in example 1 was tested, and a 360min irradiation experiment was performed on the sample using an ultraviolet lamp and a xenon lamp, and the results are shown in fig. 7.
As can be seen from FIG. 7, the fluorescence intensity of the carbon quantum dots slightly decreases after being irradiated by two different light sources for a long time. Compared with the irradiation of a 300W xenon lamp, the fluorescence intensity of the carbon quantum dots is reduced more slowly under the irradiation of a 365nm ultraviolet lamp, and the intensity of the carbon quantum dots is still more than 85% of that of the quantum dots which are not irradiated by light. The fluorescence intensity of the quantum dots after 360min xenon lamp irradiation is still over 72%. The reason for this is probably that the xenon lamp has large output power and high energy given to the quantum dots, so that the photooxidation of the carbon quantum dots is enhanced, and the falling of hydrophilic groups on the surfaces of the carbon quantum dots in the aqueous solution is accelerated, thereby causing the continuous reduction of the fluorescence intensity of the carbon quantum dots. In general storage and use processes, conditions are rarely met, and the conditions are also shown in a side view to show that the prepared upconversion fluorescent carbon quantum dot has good photobleaching resistance even under extreme conditions.
Test example 5
The emission spectra of the carbon quantum dots prepared in example 1 under the excitation of ultraviolet light and visible light are tested, specifically as shown in fig. 8, (a) is 290-530 nm; (b) 560 and 760 nm.
FIG. 8 shows Photoluminescence (PL) of Carbon Quantum Dots (CQDs) at different excitation wavelengths. As the excitation wavelength increases (290-530nm), the position of the maximum emission peak shifts to longer wavelengths, and the PL intensity increases first and then decreases. A maximum emission peak at 510nm can be observed under 450nm excitation. The excitation-dependent fluorescence properties of CQDs are attributed to the different surface states and size dispersion of nanomaterials. Notably, it also showed significant up-conversion fluorescence. When the excitation wavelength is 560-760nm, the up-conversion PL spectrum of the CQDs is 300-550 nm. The excitation wavelength is 600nm, with the strongest emission, at 350 nm. This property can be attributed to the multi-photon mobility process in which the simultaneous absorption of two or more photons results in emission at a shorter wavelength than the excitation wavelength. Thus, the combination of CQDs with existing semiconductor photocatalysts would likely increase their availability to sunlight, thereby increasing their photocatalytic capabilities.
Test example 6
The composite materials prepared in examples 15 to 19 were tested for their degradation under UV irradiation and simulated sunlight, and the results are shown in FIGS. 9 to 10, where Blank indicates the test results using water as a Blank, TiO2Represents pure TiO2Test results on samples, CQDS indicates that TiO was not added in example 152Test results of the product obtained in the case.
FIG. 9 shows CQDs and TiO2And the photocatalytic degradation curve of the nano composite material with different carbon quantum dot contents for degrading 40ppm methyl orange under the light of an ultraviolet lamp. As can be seen from the figure, CQDs/TiO with different carbon quantum dot contents are prepared under the irradiation of an ultraviolet lamp2The composite material has photocatalytic degradation capability, wherein the photocatalytic activity of CT-1 is the best. The concentration of methyl orange was almost unchanged throughout the photocatalytic experiment, and pure CQDs had no photocatalytic ability for methyl orange. After 480min under the irradiation of ultraviolet light, 81.84% of methyl orange is catalyzed and degraded by CT-1, and TiO is2The degradation rates of CT-100, CT-20, CT-10 and CT-2 to methyl orange are 46.85%, 43.59%, 49.71%, 54.18% and 69.21% respectively. In addition, CQDs/TiO became adsorbed during equilibrium in dark conditions 30 minutes prior to photocatalysis2The adsorption capacity of the composite material to methyl orange is also remarkably improved, which is probably because the composite material has larger specific surface area and more adsorption sites.
Except that the CQDs/TiO with different carbon quantum dot contents are evaluated by ultraviolet lamp irradiation2The photocatalytic activity was evaluated by using a 300W xenon lamp to simulate sunlight, and the results are shown in fig. 10. FIG. 10 shows CQDs and TiO2And the photocatalytic degradation curve of the nano composite material for degrading 40ppm methyl orange under the simulated sunlight irradiation of a 300W xenon lamp. As can be seen from FIG. 10, under simulated solar radiation, different carbons were producedCQDs/TiO of quantum dot content2The composite material shows photocatalytic degradation capability and is compared with pure TiO2Has stronger photocatalysis capability. After 480min under xenon lamp irradiation, the degradation rates of CT-100, CT-20, CT-10, CT-2 and CT-1 to methyl orange are 34.76%, 49.33%, 53.28%, 60.59% and 61.71%, respectively, while pure TiO2The photocatalytic degradation rate of (2) is only 21.20%. In addition, the concentration of methyl orange was almost unchanged throughout the photocatalytic experiment, and pure CQDs also had no photocatalytic ability for methyl orange.
Test example 7
The composite material prepared in example 19 was tested for its degradation curve against methyl orange under different light source irradiation, and the results are shown in fig. 11.
As can be seen from FIG. 11, CT-1 shows different photocatalytic activities under different light sources. After 360min of illumination, the degradation rate of CT-1 to methyl orange under 365nm wavelength reaches 78.56%, the degradation rate of CT-1 to methyl orange under 420nm wavelength is only 29.02%, the degradation rate to methyl orange under 600nm wavelength is 70.56%, and the degradation rate to methyl orange under simulated sunlight irradiation is only 56.57%. This demonstrates CQDs/TiO2The composite material can be used for photocatalysis by utilizing the up-conversion characteristic of the fluorescent carbon quantum dots. It converts long-wave light into short-wave high-energy ultraviolet light (300-2Degrading methyl orange. This will be CQDs/TiO2Photocatalysis of composite materials in indoor environments not exposed to sunlight provides a new direction of research.
Test example 8
The photocatalytic activity of the composite materials prepared in examples 19 and 20 was tested for methyl orange under the irradiation of a light source at 600nm, and the results are shown in fig. 12.
The CT-1 and CT-0 composite nano materials prepared in different modes are subjected to a photocatalysis experiment on methyl orange under the irradiation of an orange LED lamp light source with the wavelength of 600nm, and the result is shown in figure 12. After 360min of irradiation, pure TiO2The degradation rate of the compound on methyl orange is 13.66%, the degradation rate of the compound in-situ prepared CT-1 on methyl orange reaches 70.56%, and the degradation rate of the compound later prepared CT-0 on methyl orange is 42.53%. This demonstrates CQDs/T prepared by in situ compoundingiO2Material, carbon quantum dots can be better bonded to TiO2And the photocatalyst has better photocatalytic performance.
Test example 9
The degradation curve of the composite material prepared in example 19 to an aqueous formaldehyde solution and a first order kinetic curve fit curve were tested, and the results are shown in fig. 13.
A photocatalytic degradation experiment was performed on 40mg/L formaldehyde solution using a CT-1 sample with a 365nm UV lamp (3W). As shown in FIG. 13 (a), the degradation rate of CT-1 to formaldehyde reached 54.56% after 480min irradiation. Furthermore, pseudo first order kinetic simulations were performed for CT-1 photocatalysis, and as shown in FIG. 13 (b), the reaction rate constant was 0.00157cm-1And the fitting R2 value is 0.9709, so that the fitting effect is good. The above results indicate CQDs/TiO2The composite nano material has a strong purification effect on formaldehyde, and can be degraded by more than half by 480min photocatalysis even in the presence of formaldehyde with higher concentration.
Test example 10
The emission spectra under ultraviolet and visible light excitation of the carbon quantum dots prepared in comparative example 5 were tested, and the results are shown in fig. 14. In comparative example 5, the emission spectrum of the carbon quantum dot under the excitation of ultraviolet light and visible light was prepared from citric acid monohydrate and phenylenediamine as raw materials: (1) citric acid monohydrate and o-phenylenediamine: (a) 290 nm and 530 nm; (b) 560 and 760 nm. (2) Citric acid monohydrate and m-phenylenediamine: (c) 290 nm and 530 nm; (d) 560 and 760 nm. (3) Citric acid monohydrate and p-phenylenediamine: (e) 290 nm and 530 nm; (f) 560 and 760 nm.
Tests show that the carbon quantum dot prepared in the comparative example has a fluorescence emission peak in the wavelength band of 400-600nm when excited by 290-530nm light. Meanwhile, under the excitation of light with different wavelengths, the fluorescence emission peak of the material has small-amplitude red shift, which shows that the prepared carbon quantum dots have dependence on the excitation wavelength. When excited by long-wavelength light (560-. This indicates that the prepared carbon quantum dots have upconversion capability, but cannot upconvert visible light to ultraviolet light.
In summary, the inventors found that the carbon quantum dot doped with N can be prepared by a one-step hydrothermal method by using a carbon source, phenylenediamine and water as raw materials, so that a complicated purification step caused by passivation or surface modification is avoided, the method is a simple one-pot method for preparing N-CQDs, and the prepared N-doped carbon quantum dot has good up-conversion fluorescence property and fluorescence stability.
The embodiment of the invention also provides a carbon quantum dot-titanium dioxide composite material and a preparation method thereof, wherein the carbon quantum dot-titanium dioxide composite material is subjected to in-situ compounding by a one-step hydrothermal method, or is prepared into CQDs-TiO by a later-stage compounding method2The composite nano material can obviously improve the photocatalysis capability of the titanium dioxide and has good application prospect.
The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (14)
1. A method for preparing a carbon quantum dot, comprising: carrying out hydrothermal reaction on a carbon source and a phenylenediamine aqueous solution to obtain a carbon quantum dot stock solution;
the phenylenediamine is m-phenylenediamine, and the carbon source is selected from at least one of L-glutamic acid or derivatives thereof;
the temperature of the hydrothermal reaction is 200 ℃ and 220 ℃, and the reaction time is 5.5-6.5 h;
the molar ratio of the carbon source to the phenylenediamine is 1: 0.8-1.2.
2. The method for producing a carbon quantum dot according to claim 1, wherein the carbon source is L-glutamic acid.
3. The method for producing a carbon quantum dot according to claim 1, wherein a molar ratio of the carbon source to the phenylenediamine is 1:0.9 to 1.1.
4. A carbon quantum dot produced by the production method according to any one of claims 1 to 3.
5. A method for producing a carbon quantum dot-titanium dioxide composite material, characterized in that the production method according to any one of claims 1 to 3 is employed, and titanium dioxide is added to the aqueous solution before hydrothermal reaction.
6. The production method according to claim 5, wherein the molar ratio of the carbon source to the titanium dioxide is 1:1 to 100.
7. The production method according to claim 6, wherein the molar ratio of the carbon source to the titanium dioxide is 1: 1-2.
8. The method according to claim 5, wherein after completion of the reaction, lyophilization is performed.
9. A preparation method of a carbon quantum dot-titanium dioxide composite material is characterized by comprising the following steps: preparing a carbon quantum dot stock solution by the preparation method of any one of claims 1 to 3, and then mixing and reacting the carbon quantum dot stock solution and titanium dioxide.
10. The production method according to claim 9, wherein the molar ratio of the carbon source to the titanium dioxide is 1:1 to 100.
11. The production method according to claim 10, wherein the molar ratio of the carbon source to the titanium dioxide is 1: 1-2.
12. The preparation method of claim 11, wherein the mixing reaction of the carbon quantum dot stock solution and the titanium dioxide is carried out for 20-30h under the condition of avoiding light.
13. The method of claim 12, wherein the freeze-drying is performed after the reaction between the carbon quantum dot stock solution and the titanium dioxide is completed.
14. A carbon quantum dot-titanium dioxide composite material, characterized by being produced by the production method according to any one of claims 5 to 13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010949585.7A CN112048297B (en) | 2020-09-10 | 2020-09-10 | Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010949585.7A CN112048297B (en) | 2020-09-10 | 2020-09-10 | Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112048297A CN112048297A (en) | 2020-12-08 |
| CN112048297B true CN112048297B (en) | 2021-11-16 |
Family
ID=73611656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010949585.7A Active CN112048297B (en) | 2020-09-10 | 2020-09-10 | Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112048297B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112961669A (en) * | 2021-02-01 | 2021-06-15 | 苏州星烁纳米科技有限公司 | Preparation method of solid-phase carbon quantum dot, solid-phase carbon quantum dot prepared by same and light-emitting device |
| CN113462385B (en) * | 2021-07-20 | 2022-07-12 | 苏州大学 | Composite material capable of realizing photo-thermal blending and preparation method and application thereof |
| CN114058370A (en) * | 2021-10-20 | 2022-02-18 | 华南师范大学 | Carbon dot material and preparation method and application thereof |
| CN115044370A (en) * | 2022-06-08 | 2022-09-13 | 福建农林大学 | Hetero-element-doped red light carbon dot for detecting various metal ions and preparation method and application thereof |
| CN115090111B (en) * | 2022-06-23 | 2023-11-14 | 烟台海誉新材料有限公司 | Preparation and application methods of formaldehyde remover for home use |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104923202B (en) * | 2015-04-29 | 2017-10-24 | 东华大学 | A kind of preparation method of nitrogen-doped carbon quantum dot/composite titania material |
| CN106995699B (en) * | 2017-05-31 | 2018-06-01 | 中国矿业大学 | Carbon quantum dot prepared by the method and this method of the adjustable fluorescent carbon point of a large amount of synthetic wavelengths |
| CN107876036A (en) * | 2017-09-15 | 2018-04-06 | 东北林业大学 | A kind of CQDs/TiO2The preparation method of sunlight photocatalysis agent |
| CN107876035B (en) * | 2017-11-24 | 2020-06-12 | 中国科学院上海硅酸盐研究所 | Carbon quantum dot/titanium dioxide composite photocatalytic material and preparation method and application thereof |
| CN108018039B (en) * | 2017-12-18 | 2020-08-25 | 河北工业大学 | Preparation method and application of white light emitting carbon quantum dots |
| CN111100637B (en) * | 2020-02-14 | 2022-03-29 | 太原理工大学 | Green fluorescent carbon quantum dot based on high fluorescent quantum yield and preparation method thereof |
-
2020
- 2020-09-10 CN CN202010949585.7A patent/CN112048297B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112048297A (en) | 2020-12-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112048297B (en) | Carbon quantum dot, carbon quantum dot-titanium dioxide composite material and preparation method thereof | |
| Aghamali et al. | Synthesis and characterization of high efficient photoluminescent sunlight driven photocatalyst of N-Carbon Quantum Dots | |
| Yao et al. | Carbon dots based photocatalysis for environmental applications | |
| Yu et al. | Facilely synthesized N-doped carbon quantum dots with high fluorescent yield for sensing Fe 3+ | |
| CN108690609B (en) | Synthesis method of water-soluble or oil-soluble carbon dots and fluorescent carbon dots | |
| Li et al. | Fluorescent carbon nanoparticles: electrochemical synthesis and their pH sensitive photoluminescence properties | |
| Wang et al. | Vegetable-extracted carbon dots and their nanocomposites for enhanced photocatalytic H 2 production | |
| Tan et al. | Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source | |
| Niu et al. | Facile synthesis and optical properties of nitrogen-doped carbon dots | |
| CN110205121B (en) | Room-temperature phosphorescent carbon dot material and preparation method and application thereof | |
| Li et al. | Engineering of Gd/Er/Lu-triple-doped Bi2MoO6 to synergistically boost the photocatalytic performance in three different aspects: Oxidizability, light absorption and charge separation | |
| CN108753283B (en) | Method for safely and simply preparing double-doped nitrogen and phosphorus carbon quantum dots | |
| KR101663748B1 (en) | Method of manufacturing nitrogen-doped carbon dots | |
| WO2014084797A1 (en) | Method for forming nitrogen and sulfur co-doped graphene quantum dots | |
| Vieira et al. | Synthesis of multicolor photoluminescent carbon quantum dots functionalized with hydrocarbons of different chain lengths | |
| Zhang et al. | Near-infrared light-driven photocatalytic NaYF 4: Yb, Tm@ ZnO core/shell nanomaterials and their performance | |
| Li et al. | Synthesis and characterization of copper ions surface-doped titanium dioxide nanotubes | |
| Zhu et al. | Efficient upconverting carbon nitride nanotubes for near-infrared-driven photocatalytic hydrogen production | |
| Li et al. | Blue fluorescence-assisted SrTi 1− x Cr y O 3 for efficient persistent photocatalysis | |
| Liu et al. | Facile synthesis of nitrogen and sulfur co-doped carbon dots for multiple sensing capacities: alkaline fluorescence enhancement effect, temperature sensing, and selective detection of Fe 3+ ions | |
| Li et al. | Modulation of single-band red upconversion luminescence in Er3+/Yb3+ codoped bismuth oxyiodide nanoplates by bandgap engineering and their application in NIR photocatalysis | |
| CN111748346B (en) | Up-conversion nanowire and preparation method and application thereof | |
| CN109847799A (en) | With highlight catalytic active C-dots/UiO-66-NH2The preparation method and applications of composite material | |
| Mozdbar et al. | The impact of Carbon Quantum Dots (CQDs) on the photocatalytic activity of TiO2 under UV and visible light | |
| CN110467916B (en) | Nitrogen-doped carbon quantum dot green fluorescent material and preparation method thereof |
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 |