CN115418225A - Phosphorus-doped modified carbon quantum dot and preparation method of composite photocatalyst thereof - Google Patents

Phosphorus-doped modified carbon quantum dot and preparation method of composite photocatalyst thereof Download PDF

Info

Publication number
CN115418225A
CN115418225A CN202210828383.6A CN202210828383A CN115418225A CN 115418225 A CN115418225 A CN 115418225A CN 202210828383 A CN202210828383 A CN 202210828383A CN 115418225 A CN115418225 A CN 115418225A
Authority
CN
China
Prior art keywords
mol
phosphorus
cds
carbon quantum
preparation
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.)
Granted
Application number
CN202210828383.6A
Other languages
Chinese (zh)
Other versions
CN115418225B (en
Inventor
郭双祯
李祖钰
李炟
臧立华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Qilu University of Technology
Original Assignee
Qilu University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Qilu University of Technology filed Critical Qilu University of Technology
Priority to CN202210828383.6A priority Critical patent/CN115418225B/en
Publication of CN115418225A publication Critical patent/CN115418225A/en
Application granted granted Critical
Publication of CN115418225B publication Critical patent/CN115418225B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
    • 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
    • B01J27/14—Phosphorus; Compounds 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
    • B01J27/14—Phosphorus; Compounds thereof
    • B01J27/16—Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B01J31/22—Organic complexes
    • B01J31/2204—Organic complexes the ligands containing oxygen or sulfur as complexing atoms
    • B01J31/2208—Oxygen, e.g. acetylacetonates
    • B01J31/2226—Anionic ligands, i.e. the overall ligand carries at least one formal negative charge
    • B01J31/223—At least two oxygen atoms present in one at least bidentate or bridging ligand
    • B01J31/2239—Bridging ligands, e.g. OAc in Cr2(OAc)4, Pt4(OAc)8 or dicarboxylate ligands
    • B01J35/39—
    • 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
    • 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
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/80—Complexes comprising metals of Group VIII as the central metal
    • B01J2531/84—Metals of the iron group
    • B01J2531/847—Nickel
    • 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
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/44—Time
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Abstract

The invention provides a preparation method of phosphorus-doped modified carbon quantum dots and a composite photocatalyst thereof, which comprises the steps of mixing lignin and red phosphorus in a mass ratio of 1-10; mixing the mixed material with sodium hydroxide according to the mass ratio of 60-70. Phosphorus enters the carbon quantum dots by doping, exists in the chemical bond forms of C-P, C-O-P and C-P-O, and is more firmly combined and more uniformly distributed. The P-CDs/Ni-MOL composite photocatalyst is prepared by adding Ni-MOL into the phosphorized and modified carbon quantum dots for hydrothermal reaction, can realize the degradation of tetracycline in a water body under visible light or natural light, and is clean and sustainable.

Description

Phosphorus-doped modified carbon quantum dot and preparation method of composite photocatalyst thereof
Technical Field
The invention belongs to the field of environmental protection, relates to a preparation method of a photocatalyst, and particularly relates to a preparation method of a phosphorus-doped modified carbon quantum dot and a composite photocatalyst thereof.
Background
In recent years, in the field of photocatalytic degradation, metal-organic framework Materials (MOFs) have received sufficient attention due to their advantages of adjustable structure, high porosity, good photoelectric properties, and the like. Compared with MOFs with a three-dimensional structure, two-dimensional MOFs have the advantages of unique structure, ultrahigh porosity, high surface active metal site/active metal site ratio, large specific surface area and high conductivity, and are one of the most active fields in photoelectrocatalysis. However, the development of two-dimensional MOFs is still restricted by two main problems of narrow absorption spectrum and low utilization rate of photo-generated electrons (high recombination rate of photo-generated electron-hole pairs).
The carbon quantum dots have unique structures and physicochemical properties, such as wider light absorption range, up-conversion luminescence behavior, good electron transmission performance and the like, can directly capture near infrared light and convert the near infrared light into visible light, and can be compounded with two-dimensional MOFs to be used as a composite material of a semiconductor photocatalyst. Researches prove that the carbon quantum dots are combined with the photocatalyst, so that the light absorption range of the photocatalyst can be remarkably widened. In addition, the carbon quantum dots can be simultaneously used as an electron donor and an electron acceptor, play a role of a carrier transfer bridge in the composite catalyst, and can effectively reduce the recombination rate of electron-hole pairs. In addition, the energy band of the composite photocatalyst can be adjusted by doping the carbon quantum dots, so that the absorption of the composite photocatalyst on visible light can be increased, and the photocatalytic efficiency is improved. The doped atoms can form lattice defects, so that the recombination of photogenerated electrons and holes is avoided, and the photocatalytic performance can be improved. At present, the doped atoms reported in the literature include N, S, B, P, and compared with other heteroatoms, the substitution defect formed by the maximum atomic radius of the P atom is the largest, the formed C-P bond length is obviously longer than the C-X (X = N, S, B) bond length, and the doping of the phosphorus atom brings larger structural deformation to the photocatalyst. In terms of electronegativity, N (3.04) and S (2.58) have larger electronegativity than carbon (2.55), phosphorus (2.19) has smaller electronegativity than C, and the polarity of C-P bond is opposite to that of C-N, C-S bond, so that phosphorus-doped carbon quantum dots can generate more defect sites and new active sites different from nitrogen and sulfur doping.
However, the prior art preparation of phosphorus-doped carbon quantum dots generally uses phosphorus tribromide, sodium dihydrogen phosphate and phosphorus-containing precursors of phosphoric acid. However, the carbon quantum dots prepared by using these precursors have problems of low phosphorus content and non-uniform distribution of phosphorus. The existing phosphorus doping means comprise a hydrothermal method, a high-temperature pyrolysis method, a dipping-high-temperature treatment combined method, a sol-gel-high-temperature treatment combined method, a high-temperature and high-pressure method and the like, the preparation period is long, the process is complex, and the phosphorus utilization rate is low. Chinese patent document CN 110790256A (201910997630.3) discloses a method for simultaneously preparing carbon quantum dots and porous carbon by a one-pot method, corncob lignin and phosphoric acid are used as raw materials, and carbon quantum dot solid doped with nitrogen and phosphorus elements is obtained under the conditions of high temperature and high pressure. In the method for preparing the carbon quantum dots by phosphorus doping in the above patent, phosphoric acid is used as a phosphorus source, and the method for doping modification is a high-temperature high-pressure method. Phosphoric acid is toxic and has strong corrosivity, and in the preparation process by adopting a high-temperature high-pressure method, the phosphoric acid can be heated and decomposed to generate highly toxic phosphorus oxide smoke and toxic waste liquid. However, the phosphorus doping method has huge environmental risks, and the preparation method has high energy consumption and low phosphorus doping amount. Chinese patent document CN109453795A (201811499217.6) discloses a CQDs/P photocatalytic composite material and a preparation method and application thereof, wherein the CQDs/P photocatalytic composite material is composed of flaky red phosphorus and carbon quantum dots, the red phosphorus has a mesoporous structure, the carbon quantum dots are distributed on the surface of the red phosphorus, and the red phosphorus exists in a monoclinic phase. The CQDs/P composite material provided by the method can effectively inhibit the recombination of electrons and holes during visible light catalytic reaction, and the photocatalytic efficiency of the catalyst is obviously improved. However, in the preparation method of the CQDs/P composite material in the patent, carbon quantum dots are distributed on the surface of a monoclinic phase, and the combination is not firm and is easy to fall off, so that the photocatalytic performance is reduced. In addition, in the above patent, red phosphorus is used as a carrier, the red phosphorus is of a mesoporous structure, the specific surface area is small, and the surface is of a smooth structure, which is not favorable for combining with carbon quantum dots. Although triphenylphosphine is the best phosphorus precursor found so far, which can effectively modify carbon quantum dots by forming strong C — P bonds, its toxicity and high price limit its further application.
Disclosure of Invention
The invention provides a phosphorus-doped modified carbon quantum dot and a preparation method of a composite photocatalyst thereof, aiming at solving the technical problems of complex preparation method, high energy consumption and great environmental pollution in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of phosphorus modified carbon quantum dots (P-CDs) comprises the following steps:
mixing lignin and red phosphorus in a mass ratio of 1-10, adding ethanol, and performing ball milling for 5-10 h at a ball milling speed of 800-900 rpm to obtain a ball-milled mixed material; mixing the mixed material with sodium hydroxide according to the mass ratio of 60-70.
Preferably, the mass ratio of the lignin to the red phosphorus is 1.5-6:1. Preferably, the mass ratio of the added volume of the ethanol to the lignin is 1-2 mL/g. ZrO is used for ball milling 2 The number of the balls is 25-35. The ball milling time is preferably 7 to 9 hours.
Preferably, the solvent in the hydrothermal reaction is water, and the mass ratio of the volume of the solution to the solid (the mass sum of the mixed material and the sodium hydroxide) is 20 to 25mL/g.
Before the hydrothermal reaction, the raw materials of the hydrothermal reaction are subjected to ultrasonic treatment, so that the mixed material and sodium hydroxide are uniformly dispersed in the solvent.
The centrifugal speed is 10000rpm and the centrifugation is carried out for 5min.
The phosphorus content of the phosphorized and modified carbon quantum dot obtained by the invention is high (the phosphorus content is 8.5-11%), more substitution defects can be formed, and the separation of electrons and holes in a photon-generated carrier is facilitated, so that the photocatalysis performance can be improved.
The invention adopts red phosphorus as a phosphorus source to modify the carbon quantum dots, and compared with other phosphorus sources, the red phosphorus has the advantages of no toxicity, no corrosion and low price. However, under the standard condition of red phosphorus, the red phosphorus is solid, large in particle and low in activity, and the carbon quantum dots are difficult to effectively modify by adopting a conventional method. According to the invention, lignin and red phosphorus are treated by ball milling, the rotation speed exceeds 800rpm in the ball milling process, and high energy generated by collision can convert red phosphorus into atomic phosphorus, so that the problems of large red phosphorus particles and low activity are solved. In addition, the physical structure of lignin can be destroyed by ball milling, atomic phosphorus can be combined with lignin fragments in high-energy collision, and the distribution of the phosphorus is more three-dimensional and uniform. Compared with other doping methods, the ball milling method has the advantages of simple preparation method, low energy consumption, no secondary pollution and short period. In the invention, phosphorus is doped into the carbon quantum dots by high-speed ball milling and exists in the chemical bond forms of C-P, C-O-P and C-P-O, so that the combination is firmer and the distribution is more uniform.
The invention also provides a preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst, which is obtained by adding Ni-MOL into P-CDs for hydrothermal reaction. The method specifically comprises the following steps:
(1) Preparing Ni-MOL:
dropwise adding a DMF (dimethyl formamide) solution of terephthalic acid into a DMF solution of nickel salt, and adjusting the pH of the solution to be alkaline to obtain a mixture; and (3) reacting the mixture at the temperature of 115-125 ℃ for 9-11 h, filtering to obtain a precipitate, and drying to obtain the product Ni-MOL with the two-dimensional layered structure.
The concentration of terephthalic acid in the DMF solution of terephthalic acid is preferably 0.03 to 0.04g/mL, more preferably 0.03 to 0.035g/mL.
Preferably, the nickel salt is selected from Ni (NO) 3 ) 2 、NiCl 2 、NiSO 4 One or more of them. The concentration of the nickel salt in the DMF solution of the nickel salt is 0.04-0.05 g/mL; more preferably 0.04 to 0.045g/mL.
Preferably, the pH of the solution is adjusted to 10 to 11, and the pH of the solution is adjusted by using a sodium hydroxide solution or a potassium hydroxide solution. The concentration of the solution is 0.035-0.045 mol/L.
Preferably, the drying conditions are as follows: at 50 ℃ for 12 hours.
(2) Preparing a P-CDs/Ni-MOL composite photocatalyst:
adding Ni-MOL into P-CDs to obtain a mixture, performing ultrasonic dispersion, performing hydrothermal reaction at 115-125 ℃ for 9-11 h, and drying the product to obtain the composite photocatalyst (P-CDs/Ni-MOL).
Preferably, the concentration of Ni-MOL in the mixture is 0.015 to 0.025g/mL.
The photocatalyst is prepared by taking two-dimensional MOFs (Ni-MOL) as a carrier, the Ni-MOL has the advantages of large specific surface area and many active sites, the surface is of a porous structure, and carbon quantum dots can be semi-embedded on the surface of the Ni-MOL, so that the combination is firmer. The composite photocatalyst (P-CDs/Ni-MOL) obtained by the invention has 13-16% of Ni load, 4-11% of P load and 33-40% of carbon (at% of the above), and the sum of atomic percentages of C, ni, P and O in the composite photocatalyst is 100%. Preferably, the Ni content is 14 to 15%, the P content is 8 to 9%, the C content is 36 to 37%, and the O content is 40 to 41%.
The invention also provides application of the P-CDs/Ni-MOL composite photocatalyst in tetracycline degradation.
The invention has the beneficial effects that:
a) Based on the principle of recycling of wastes, the research uses cheap and easily-obtained renewable agricultural waste lignin as a carbon source to prepare the composite photocatalyst.
b) The method for modifying the carbon quantum dots is innovatively characterized in that a method combining red phosphorus and mechanical ball milling is adopted in a synthetic method. Compared with other preparation methods, the preparation method avoids preparation steps with high energy consumption and high pollution, and has the advantages of simple preparation method, short period and low energy consumption.
c) The prepared composite photocatalyst is convenient to use, has stable chemical properties (can still keep 91.6 percent of tetracycline removal rate after being recycled for 5 times), is not easily influenced by external environmental factors, and is easy to store;
d) The P-CDs/Ni-MOL composite photocatalyst can degrade tetracycline in water under visible light or natural light, and is clean and sustainable. Use ofDegrading tetracycline in water by using a P-CDs/Ni-MOL composite photocatalyst, wherein the initial concentration of the tetracycline is 50mg/L, the addition amount of the photocatalyst is 1.0g/L, adsorbing saturation is carried out under the dark reaction condition, and visible light is used (optical power density: 11 mW/cm) 2 ) After tetracycline is removed by irradiation (the irradiation time is 120min, and the removal rate reaches 98.98%), the tetracycline can be regenerated by ethanol washing.
Drawings
FIG. 1 is a transmission electron micrograph of a composite photocatalytic material; wherein (a) is a transmission electron microscope of Ni-MOL; (b) is a high power transmission electron microscope of Ni-MOL; (c) is a transmission electron microscope of P-CD/Ni-MOL; and (d) high power transmission electron microscopy at P-CD/Ni-MOL.
FIG. 2 is an EDS spectrum of P (1) -CD/Ni-MOL.
FIG. 3 is an atomic force microscope spectrum of Ni-MOL (a) and P (1) -CD/Ni-MOL (b).
FIG. 4 is an XRD spectrum of the composite photocatalytic material.
FIG. 5 is an infrared spectrum of the composite photocatalytic material.
FIG. 6 is a total X-ray photoelectron spectroscopy (XPS) spectrum of the composite photocatalytic material.
FIG. 7 is a high resolution X-ray photoelectron spectrum (XPS) P2P spectrum of the composite photocatalytic material.
FIG. 8 is a partial enlarged view of P in an X-ray photoelectron spectroscopy (XPS) total spectrum of the composite photocatalytic material.
FIG. 9 is a graph showing the photocatalytic degradation of tetracycline by the composite photocatalytic material.
Detailed Description
The invention is further described in the following description with reference to the figures and specific examples, which should not be construed as limiting the invention. The lignin in the invention is a common commercial product.
Example 1
A preparation method of a carbon quantum dot composite nano photocatalyst,
(1) Preparing Ni-MOL: terephthalic acid (0.166 g) was mixed with 5mL of DMF solution and stirred for 10 minutes to form solution A. Mixing Ni (NO) 3 ) 2 (0.436 g) was added to 10mL of DMF solution and stirred for 10 minutes to form solution B. Then, solution A was droppedTo solution B was added, followed by the slow dropwise addition of 2mL NaOH (0.04 mol/L). The mixture was then transferred to a hydrothermal reaction kettle and reacted at 120 ℃ for 10h. The resulting precipitate was collected by filtration, washed with DMF and the collected sample was dried in an oven at 50 ℃ for 12 hours to obtain the final product (Ni-MOL).
(2) Preparation of carbon quantum dots (P (0) -CDs): 3.0g of lignin was added to the jar, followed by 5mL of ethanol and 30 ZrO particles 2 And (4) ball milling for 8 hours at a ball milling speed of 800 rpm. After the ball milling is finished, 2.0g of the obtained material and 0.3g of sodium hydroxide are added into 50mL of solution, ultrasonic treatment is carried out for 10 minutes, the mixed solution is transferred into a hydrothermal reaction kettle, and the reaction is carried out for 5 hours at 180 ℃. And after the hydrothermal reaction kettle is naturally cooled, centrifuging the obtained liquid at 10000rpm for 5min, wherein the centrifuged liquid is the carbon quantum dots and is marked as (P (0) -CDs).
(3) Preparing a composite photocatalyst (P-CDs/Ni-MOL): 1.0g of Ni-MOL was added to 50mL of the P (0) -CDs solution and sonicated for 15 minutes. Transferring the mixed solution into a hydrothermal reaction kettle, and reacting for 10 hours at 120 ℃. After natural cooling, the resulting precipitate was collected by filtration and washed several times with water and ethanol. And drying the collected sample in a vacuum oven at 60 ℃ for 12 hours to obtain the sample, namely the composite photocatalyst, which is recorded as P (0) -CDs/Ni-MOL. The carbon and Ni contents of the composite photocatalyst are 40.51% and 16.37%, respectively.
Example 2
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from that of the embodiment 1 in that 3.0g of lignin and 0.5g of red phosphorus are added into a ball milling tank in the step (2), and other conditions are the same as those of the embodiment 1. And (3) the liquid obtained in the step (2) is phosphorus modified carbon quantum dots which are marked as (P (0.5) -CDs). The composite photocatalyst is marked as P (0.5) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are respectively 4.37%,39.84% and 15.32%.
Example 3
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from that of the embodiment 1 in that 3.0g of lignin and 1.0g of red phosphorus are added into a ball milling tank in the step (2), and other conditions are the same as those of the embodiment 1. And (3) the liquid obtained in the step (2) is phosphorus modified carbon quantum dots which are marked as (P (1) -CDs). The composite photocatalyst is marked as P (1) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are respectively 8.52%,36.43% and 14.35%.
Example 4
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from that of the embodiment 1 in that 3.0g of lignin and 1.5g of red phosphorus are added into a ball milling tank in the step (2), and other conditions are the same as those of the embodiment 1. And (3) the liquid obtained in the step (2) is phosphorus modified carbon quantum dots which are marked as (P (1.5) -CDs). The composite photocatalyst is marked as P (1.5) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are respectively 9.43%,35.31% and 13.22%.
Example 5
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from that of the embodiment 1 in that 3.0g of lignin and 2.0g of red phosphorus are added into a ball milling tank in the step (2), and other conditions are the same as those of the embodiment 1. And (3) the liquid obtained in the step (2) is phosphorus modified carbon quantum dots which are marked as (P (2.0) -CDs). The composite photocatalyst is marked as P (2.0) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are respectively 10.81%,33.29% and 13.02%.
Comparative example 1
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from the preparation method of the P modified carbon quantum dot in the embodiment 3. The preparation method of the P modified carbon quantum dot comprises the following steps: weighing 3.0g of lignin, adding 3.16g of phosphoric acid, adding deionized water, wherein the ratio g of the lignin to the deionized water is as follows: mL is 1:10 Stirring for 30min at 70 ℃ until the dispersion is uniform, then keeping the temperature at 180 ℃ for 6h under the pressure of 1.6MPa, and stopping heating after the reaction is finished.
Comparative example 2
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is the same as that in example 3 except that red phosphorus and lignin are mixed and then are not subjected to ball milling.
The experiment for degrading tetracycline by the composite photocatalyst through photocatalysis comprises the following steps:
preparing a tetracycline solution with an initial concentration of 50mg/L, example 1E5 adding the composite photocatalyst and the Ni-MOL composite material obtained in the step (1) into a tetracycline solution according to the addition amount of 1.0g/L respectively, adsorbing to saturation (4 hours) under the dark reaction condition, and using visible light (optical power density: 11 mW/cm) 2 ) Irradiating, sampling every 20min, and detecting and analyzing the tetracycline removal rate.
Product characterization of the composite photocatalytic material:
FIG. 1 shows Ni-MOL and P-CD/Ni-MOL transmission electron microscopy and high power transmission electron field. As can be seen from (a) and (b) of FIG. 1, ni-MOL is a two-dimensional layered structure, and 0.31nm of lattice fringes corresponds to the 100 crystal plane of Ni-MOL. FIGS. 1 (c) and (d) are a transmission electron microscope and a high-power transmission electron microscope of P-CD/Ni-MOL, and it can be seen that P-CD/Ni-MOL has a layered structure, and P-CDs are uniformly supported on the Ni-MOL. Wherein the lattice fringes of 0.36nm and 0.31nm correspond to the 110 crystal plane of P-CDs and the 100 crystal plane of Ni-MOL, respectively, which proves the success of the combination of P-CDs and Ni-MOL.
FIG. 2 is an EDS spectrum of P (1.0) -CD/Ni-MOL showing a uniform distribution of C, O, ni and P, which indicates that P-CDs are uniformly distributed on the Ni-MOL rather than agglomerated together. The elemental percentages of C, O, ni, and P were 36.43%,40.70%,8.52%, and 14.35%.
FIG. 3 is an atomic force microscope image of the product, (a) and (b) are an atomic force microscope image of Ni-MOL and P (1.0) -CD/Ni-MOL, respectively. As can be seen from the figure, the Ni-MOL surface became rough after loading with P-CDs, and irregular spherical particles were clearly observed, which indicates that P-CDs are semi-mosaic distributed on the Ni-MOL surface.
FIG. 4 shows XRD spectra of CDs (i.e., P (0) -CDs), ni-MOL and P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2). It can be seen from the figure that 8.5 ° and 16.9 ° of Ni — MOL correspond to the 010 and 100 crystal planes, respectively. For CDs, the peaks at 8.1 °,22.9 ° and 31.6 ° correspond to the internal lamellar structure of the graphite phase CDs. P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2) has characteristic peaks of both Ni-MOL and CDs, indicating that CDs have been successfully loaded onto Ni-MOL. No other characteristic peak is found on the P (X) -CD/Ni-MOL, which indicates that the P element is highly dispersed in the composite photocatalyst and does not cause crystal form change, and the graphite-like layered configuration of the carbon quantum dots is not changed. As the amount of P doping increases, the characteristic peak at 31.6 ° shifts to a lower angle, indicating that P is doped into the lattice of CDs, rather than forming other species. In the figure, P (0) -CD/Ni-MOL which is not doped with P has impurity peaks at about 58 degrees and 38 degrees, and other P (X) -CD/Ni-MOL which is doped with phosphorus has no obvious impurity peaks. This is probably due to the fact that in the hydrothermal process, a small amount of Ni-MOL decomposes to form nickel hydroxide, which is present in a small amount and has negligible effect on the photocatalytic effect.
FIG. 5 shows the IR spectra of Ni-MOL and P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2). 3467cm -1 The peak corresponds to the stretching vibration peak of O-H. 1413-1668cm -1 The series of peaks corresponds to the benzene ring and the carbonyl group. 1210cm -1 The peak corresponds to the characteristic peak of the C-O bond. After introduction of P in CD/Ni-MOL, P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2) was 1180cm -1 A new peak was found, which corresponds to the stretching vibration peak of P-O. In addition, P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2) is 723cm -1 The new peak that appears corresponds to the stretching vibration of the C-P bond. 723cm with the increase of P doping amount -1 The peak intensity is increasing, indicating that P has entered the carbon lattice of CDs rather than PO in the adsorbed state 4 3- In the form of a salt. P enters carbon lattices of CDs to form substitution defects to effectively capture photon-generated carriers, which is beneficial to the separation of electrons and holes and is further beneficial to the improvement of photocatalytic performance.
FIGS. 6 to 8 show XPS spectra of Ni-MOL, P (0) -CD/Ni-MOL and P (1.0) -CD/Ni-MOL. It can be seen from FIG. 6 that P (1.0) -CD/Ni-MOL found a new peak at 133eV compared to Ni-MOL (FIG. 8), indicating that phosphorus has been successfully doped into CD/Ni-MOL. FIG. 7 shows a high resolution spectrum of P2P. It can be seen from the figure that P-CD/Ni-MOL has a distinct P2P peak compared to CD/Ni-MOL, where the peaks at 133.94, 133.45 and 132.87eV correspond to C-O-P, C-P-O and C-P = O, respectively.
FIG. 9 shows the degradation performance of Ni-MOL and P (X) -CD/Ni-MOL (X =0,0.5,1.0,1.5,2) on tetracycline under visible light. As can be seen from the figure, the degradation rate of tetracycline by Ni-MOL is 23.93% in 120 minutes. After the carbon quantum dots which are not doped with phosphorus are loaded (P (0) -CD/Ni-MOL), the degradation rate of the composite photocatalyst to tetracycline is improved to 47.69%. After the carbon quantum dots after phosphorus doping are loaded (P (X) -CD/Ni-MOL (X =0.5,1.0,1.5,2)), the photocatalytic performance of the composite photocatalyst is greatly improved, and the photocatalytic performance is ranked as P (1.0) -CD/Ni-MOL > P (1.5) -CD/Ni-MOL > P (0.5) -CD/Ni-MOL > P (2.0) -CD/Ni-MOL. When the phosphorus doping amount is 1.0g, the highest degradation performance of the composite photocatalyst on tetracycline is 98.98% within 120 min. And the experiments of degrading tetracycline by using the phosphorus modified carbon quantum dot composite nano photocatalyst obtained in the comparative examples 1 and 2 are carried out, and the degradation rate of the composite photocatalyst obtained in the comparative example 1 to tetracycline is 37.45% within 120 min. The degradation rate of the composite photocatalyst obtained in the comparative example 2 to tetracycline is 47.63%. This is because the yield of lignin decomposed into quantum dots in an acidic environment is low, which results in a decrease in carbon quantum dots supported on the surface of Ni-MOL, thereby having a large influence on photocatalytic performance. In the ball milling process, transition state atomic phosphorus can be formed in the process of converting red phosphorus into black scales, and the size of lignin can be further reduced in the ball milling process, so that the distribution of the atomic phosphorus is more uniform. Ball milling also results in the conversion of the C-O bonds on the surface of the lignin to C-O-P, C-P-O. Thereby reducing electron transfer resistance.

Claims (10)

1. A preparation method of phosphorus modified carbon quantum dots (P-CDs) is characterized by comprising the following steps:
mixing lignin and red phosphorus in a mass ratio of 1-10, adding ethanol, and performing ball milling for 5-10 h at a ball milling speed of 800-900 rpm to obtain a ball-milled mixed material; mixing the mixed material with sodium hydroxide according to a mass ratio of 60-70.
2. The method according to claim 1, wherein the mass ratio of the lignin to the red phosphorus is 1.5 to 6:1.
3. The method according to claim 1, wherein the ratio of the volume of ethanol added to the mass of lignin is 1 to 2mL/g. Preferably, the solvent in the hydrothermal reaction is water, and the mass ratio of the volume of the solution to the solid (the mass sum of the mixed material and the sodium hydroxide) is 20-25 mL/g.
4. The method of claim 1, wherein the ball milling uses ZrO 2 The number of the balls is 25-35.
5. A preparation method of a phosphorus modified carbon quantum dot composite nano photocatalyst is characterized in that Ni-MOL is added into P-CDs prepared by any one of claims 1 to 4 for hydrothermal reaction.
6. The preparation method of claim 5, wherein the Ni-MOL is added into the P-CDs to obtain a mixture, the mixture is subjected to ultrasonic dispersion, hydrothermal reaction is carried out at 115-125 ℃ for 9-11 h, and the product is dried to obtain the composite photocatalyst (P-CDs/Ni-MOL). Preferably, the concentration of Ni-MOL in the mixture is 0.015 to 0.025g/mL.
7. The method according to claim 5 or 6, wherein the Ni-MOL is prepared as follows:
dropwise adding a DMF (dimethyl formamide) solution of terephthalic acid into a DMF solution of nickel salt, and adjusting the pH of the solution to be alkaline to obtain a mixture; and (3) reacting the mixture at the temperature of 115-125 ℃ for 9-11 h, filtering to obtain a precipitate, and drying to obtain the product Ni-MOL with the two-dimensional layered structure.
8. The process according to claim 7, wherein the concentration of terephthalic acid in the DMF solution of terephthalic acid is 0.03 to 0.04g/mL, preferably 0.03 to 0.035g/mL.
Preferably, the nickel salt is selected from Ni (NO) 3 ) 2 、NiCl 2 、NiSO 4 One or more of the above; the concentration of the nickel salt in the DMF solution of the nickel salt is 0.04 to 0.05g/mL; more preferably 0.04 to 0.045g/mL.
9. A composite photocatalyst (P-CDs/Ni-MOL) is characterized in that two-dimensional MOFs (Ni-MOL) with a porous structure on the surface are used as carriers, and phosphorus-doped modified carbon quantum dots are semi-embedded on the surface of the Ni-MOL.
Preferably, the composite photocatalyst (P-CDs/Ni-MOL) has Ni loading of 13-16%, P loading of 4-11%, carbon content of 33-40% and total atomic percent of C, ni, P and O of 100%.
10. The use of the P-CDs/Ni-MOL composite photocatalyst prepared by the method of any one of claims 5 to 6 in tetracycline degradation.
CN202210828383.6A 2022-07-13 2022-07-13 Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof Active CN115418225B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210828383.6A CN115418225B (en) 2022-07-13 2022-07-13 Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210828383.6A CN115418225B (en) 2022-07-13 2022-07-13 Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof

Publications (2)

Publication Number Publication Date
CN115418225A true CN115418225A (en) 2022-12-02
CN115418225B CN115418225B (en) 2023-06-09

Family

ID=84197039

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210828383.6A Active CN115418225B (en) 2022-07-13 2022-07-13 Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof

Country Status (1)

Country Link
CN (1) CN115418225B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117582985A (en) * 2023-12-11 2024-02-23 河北工程大学 Quartz sand-based composite photocatalyst and preparation method and application thereof

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104774612A (en) * 2015-04-22 2015-07-15 北京化工大学 Preparation method of dual-wavelength fluorescence/dual-wavelength electrochemiluminescence carbon quantum dots
CN105642321A (en) * 2015-12-31 2016-06-08 青岛科技大学 Nano red phosphorus/graphene composite photocatalyst and preparation method thereof
CN106381143A (en) * 2016-08-30 2017-02-08 上海交通大学 Method for batch green synthesis of nitrogen and phosphorus doped fluorescent carbon dots
US20170050851A1 (en) * 2015-08-18 2017-02-23 Transfert Plus, Société En Commandite Method for manufacturing carbon quantum dots
CN107376967A (en) * 2017-06-27 2017-11-24 常州大学 A kind of preparation method of nitrogenous carbon quantum dot/graphite phase carbon nitride composite photo-catalyst
CN108441214A (en) * 2018-03-21 2018-08-24 王子韩 A kind of preparation method of more Heteroatom doping type carbon quantum dot fluorescence probes
CN111215112A (en) * 2020-01-17 2020-06-02 华侨大学 Preparation method and application of composite photocatalyst
CN113042004A (en) * 2021-04-13 2021-06-29 昆明理工大学 Preparation method and application of modified carbon-based material
CN113699556A (en) * 2021-08-27 2021-11-26 常州大学 CoNiMOF-BP QDs/b-CNF composite material electrocatalyst and preparation method thereof
US20210370309A1 (en) * 2020-06-02 2021-12-02 Boise State University Alloys of Black Phosphorus by Ball Milling Techniques
CN114572946A (en) * 2022-03-30 2022-06-03 贵州民族大学 Preparation method for rapidly preparing high-brightness black phosphorus quantum dot by ball milling method and black phosphorus quantum dot

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104774612A (en) * 2015-04-22 2015-07-15 北京化工大学 Preparation method of dual-wavelength fluorescence/dual-wavelength electrochemiluminescence carbon quantum dots
US20170050851A1 (en) * 2015-08-18 2017-02-23 Transfert Plus, Société En Commandite Method for manufacturing carbon quantum dots
CN105642321A (en) * 2015-12-31 2016-06-08 青岛科技大学 Nano red phosphorus/graphene composite photocatalyst and preparation method thereof
CN106381143A (en) * 2016-08-30 2017-02-08 上海交通大学 Method for batch green synthesis of nitrogen and phosphorus doped fluorescent carbon dots
CN107376967A (en) * 2017-06-27 2017-11-24 常州大学 A kind of preparation method of nitrogenous carbon quantum dot/graphite phase carbon nitride composite photo-catalyst
CN108441214A (en) * 2018-03-21 2018-08-24 王子韩 A kind of preparation method of more Heteroatom doping type carbon quantum dot fluorescence probes
CN111215112A (en) * 2020-01-17 2020-06-02 华侨大学 Preparation method and application of composite photocatalyst
US20210370309A1 (en) * 2020-06-02 2021-12-02 Boise State University Alloys of Black Phosphorus by Ball Milling Techniques
CN113042004A (en) * 2021-04-13 2021-06-29 昆明理工大学 Preparation method and application of modified carbon-based material
CN113699556A (en) * 2021-08-27 2021-11-26 常州大学 CoNiMOF-BP QDs/b-CNF composite material electrocatalyst and preparation method thereof
CN114572946A (en) * 2022-03-30 2022-06-03 贵州民族大学 Preparation method for rapidly preparing high-brightness black phosphorus quantum dot by ball milling method and black phosphorus quantum dot

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117582985A (en) * 2023-12-11 2024-02-23 河北工程大学 Quartz sand-based composite photocatalyst and preparation method and application thereof

Also Published As

Publication number Publication date
CN115418225B (en) 2023-06-09

Similar Documents

Publication Publication Date Title
CN106914265B (en) method for preparing nitrogen-doped porous nano carbon material by using biomass as carbon source through gel method
US20210331149A1 (en) Biochar-modified bismuth vanadate catalyst and preparation method and use thereof
CN107626336B (en) Preparation method and application of carbon dot/graphite-like phase carbon nitride composite photocatalyst
CN107233909B (en) Preparation method and application of strontium niobate/carbon nitride composite nano material
CN108067281B (en) Porous g-C3N4Photocatalyst and preparation method and application thereof
CN111659434B (en) CuO nanosheet/g-C 3 N 4 Preparation method and application of nanosheet heterojunction composite material
CN111185210B (en) Titanium carbide/titanium dioxide/black phosphorus nanosheet composite photocatalyst and preparation method and application thereof
CN101613100A (en) The biomass-based graphitized carbon and the microwave preparation of carbon-carbon composite
CN112844476A (en) Biomass-based carbon material loaded nano nickel catalyst and preparation method and application thereof
CN111974432A (en) Preparation method of oxygen-doped graphite-phase carbon nitride-cadmium sulfide composite material
CN112604690A (en) Method for preparing rare earth perovskite/biochar composite material by using agricultural and forestry wastes and application thereof
CN111330613A (en) Preparation method of hollow porous prismatic graphite phase carbon nitride
Ma et al. Hetero-structured ZnIn2S4-NiO@ MOF photo-catalysts for efficient hydrogen evolution
CN115418225A (en) Phosphorus-doped modified carbon quantum dot and preparation method of composite photocatalyst thereof
CN110961150A (en) Preparation method of porphyrin/carbon nitride layer-by-layer composite structure photocatalytic nanocomposite material
Qi et al. Synthesis of holey graphitic carbon nitride with highly enhanced photocatalytic reduction activity via melamine-cyanuric acid precursor route
CN112892555B (en) ZnIn synergistically modified by cavity promoter Ti (IV) and electron promoter MXene QDs2S4Photocatalyst and process for producing the same
CN111085230B (en) Preparation method and application of nitrogen-doped sludge compost visible light photocatalytic material
CN112452351A (en) Preparation method of recyclable floating type photocatalytic ciprofloxacin removal
CN109482200B (en) Porous carbon supported defected molybdenum sulfide electrocatalyst and preparation method thereof
CN115090318B (en) Preparation method and application of high specific surface area intermolecular heterojunction carbon nitride photocatalyst
CN107715882B (en) preparation method of carbon point hybrid polyhedral nickel oxide photocatalyst
CN110711599A (en) g-C3N4/Bi5O7I composite microsphere material and preparation method thereof
CN115591558A (en) Composite photocatalytic hydrogen production material NiTiO 3 /CdIn 2 S 4 Preparation method of (1)
CN112138700A (en) Bismuth phosphate-based heterojunction photocatalyst 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