CN115418225B - Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof - Google Patents

Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof Download PDF

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CN115418225B
CN115418225B CN202210828383.6A CN202210828383A CN115418225B CN 115418225 B CN115418225 B CN 115418225B CN 202210828383 A CN202210828383 A CN 202210828383A CN 115418225 B CN115418225 B CN 115418225B
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CN115418225A (en
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郭双祯
李祖钰
李炟
臧立华
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Qilu University of Technology
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Abstract

The invention provides a preparation method of a phosphorus doped modified carbon quantum dot and a composite photocatalyst thereof, which comprises the steps of mixing lignin and red phosphorus with a mass ratio of 1-10:1, adding ethanol, ball milling for 5-10 hours at a ball milling speed of 800-900 rpm to obtain a ball-milled mixed material; mixing the mixed material and sodium hydroxide according to the mass ratio of 60-70:1, performing hydrothermal reaction for 4-6 hours at 175-185 ℃, and centrifuging the hydrothermal product to obtain liquid, namely the phosphating modified carbon quantum dots. The phosphorus doping enters the carbon quantum dots and exists in the form of chemical bonds of C-P, C-O-P and C-P-O, so that the combination is firmer and the distribution is more uniform. The P-CDs/Ni-MOL composite photocatalyst is prepared by adding Ni-MOL into the phosphorization modified carbon quantum dots to carry out hydrothermal reaction, and can degrade tetracycline in water under visible light or natural light, and cleaning is sustainable.

Description

Preparation method of phosphorus doped modified carbon quantum dot and composite photocatalyst thereof
Technical Field
The invention belongs to the field of environmental protection, and relates to a preparation method of a photocatalyst, in particular 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 for their advantages of adjustable structure, high porosity, good photoelectric properties, and the like. Compared with MOFs with three-dimensional structures, two-dimensional MOFs are one of the most active fields in photoelectrocatalysis due to the advantages of unique structures, ultrahigh porosity, high surface active metal site/active metal site ratio, large specific surface area and high conductivity. However, two major problems of narrow absorption spectrum and low utilization of photo-generated electrons (high photo-generated electron-hole pair recombination rate) of two-dimensional MOFs still restrict the development of the MOFs.
The carbon quantum dots have unique structure and physical and chemical properties, such as a wider light absorption range, up-conversion luminescence behavior, good electron transmission performance and the like, can directly capture near infrared light to be converted into visible light, and can be compounded with two-dimensional MOFs to be used as a composite material of a semiconductor photocatalyst. The research proves that the combination of the carbon quantum dots and the photocatalyst can remarkably widen the light absorption range of the photocatalyst. In addition, the carbon quantum dots can be used as electron donors and electron acceptors simultaneously, 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 to visible light can be increased, and the photocatalytic efficiency is improved. The doped atoms can form lattice defects, so that the recombination of photo-generated electrons and holes is avoided, and the photocatalytic performance can be improved. At present, the doping atoms reported in the literature include N, S, B, P, compared with other hetero atoms, the largest atomic radius of the P atom forms the largest substituted defect, 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 more structural deformation to the photocatalyst. In terms of electronegativity, N (3.04) and S (2.58) are more electronegative than carbon (2.55), while phosphorus (2.19) is less electronegative than C, and the polarity of the C-P bond is opposite to that of the C-N, C-S bond, so that phosphorus-doped carbon quantum dots can produce more defect sites and new active sites different from nitrogen and sulfur doping.
However, prior art methods for preparing phosphorus doped carbon quantum dots typically use phosphorus tribromide, sodium dihydrogen phosphate, and a phosphorus containing precursor of phosphoric acid. However, the carbon quantum dots prepared by using the precursors have the problems of low phosphorus content and uneven phosphorus distribution. The existing phosphorus doping means comprise a hydrothermal method, a pyrolysis method, an immersion-high temperature treatment combination method, a sol-gel-high temperature treatment combination method, a high-temperature high-pressure method and the like, and the preparation cycle 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, which adopts corncob lignin and phosphoric acid as raw materials, and obtains carbon quantum dot solids doped with nitrogen and phosphorus elements under high temperature and high pressure conditions. In the method for preparing the carbon quantum dots by phosphorus doping in the patent, phosphoric acid is used as a phosphorus source, and the doping modification method is a high-temperature high-pressure method. The phosphoric acid is poisonous and has strong corrosiveness, and in the process of preparing the phosphoric acid by adopting a high-temperature high-pressure method, the phosphoric acid can be heated and decomposed to generate extremely toxic phosphorus oxide flue gas, and toxic waste liquid can be generated. 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, a preparation method and application thereof, wherein the CQDs/P photocatalytic composite material consists 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 form. The CQDs/P composite material provided by the preparation method can effectively inhibit the recombination of electrons and holes during the visible light catalytic reaction, and can obviously improve the photocatalytic efficiency of the catalyst. However, in the preparation method of the CQDs/P composite material in the patent, the carbon quantum dots are distributed on the surface of the monoclinic phase, so that the bonding is weak and the CQDs/P composite material is easy to fall off, and the photocatalytic performance is reduced. In the 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, so that the combination with the carbon quantum dots is not facilitated. Although triphenylphosphine can effectively modify carbon quantum dots by forming strong C-P bonds, it is the best phosphorus precursor currently found, but its toxicity and high price limit its further application.
Disclosure of Invention
The invention provides a preparation method of a phosphorus doped modified carbon quantum dot and a composite photocatalyst thereof, which aims to solve the technical problems of complex preparation method, high energy consumption and large environmental pollution in the prior art.
In order to achieve the above purpose, the present 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 with the mass ratio of 1-10:1, adding ethanol, ball milling for 5-10 h at the ball milling speed of 800-900 rpm to obtain a ball-milled mixed material; mixing the mixed material and sodium hydroxide according to the mass ratio of 60-70:1, performing hydrothermal reaction for 4-6 hours at 175-185 ℃, and centrifuging the hydrothermal product to obtain liquid, namely the phosphating modified carbon quantum dots.
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 to 35. Preferably, the ball milling time is 7-9 h.
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 sodium hydroxide) is 20-25 mL/g.
Before the hydrothermal reaction, the raw materials of the hydrothermal reaction are subjected to ultrasonic treatment, so that the mixed materials and sodium hydroxide are uniformly dispersed in a solvent.
The centrifugal speed is 10000rpm for 5min.
The phosphating modified carbon quantum dot obtained by the invention has high phosphorus content (the phosphorus content is 8.5% -11%), can form more substitution defects, is beneficial to separation of electrons and holes in a photogenerated carrier, and can improve the photocatalytic performance.
According to the invention, red phosphorus is used as a phosphorus source to remove the modified carbon quantum dots, and compared with other phosphorus sources, the red phosphorus has the advantages of no toxicity, no corrosiveness and low price. However, the red phosphorus is solid under the standard condition, has large particles and low activity, and is difficult to effectively modify the carbon quantum dots by adopting a conventional method. The invention uses ball milling to treat lignin and red phosphorus, the rotating speed exceeds 800rpm in the ball milling process, and the high energy generated by collision can convert the red phosphorus into atomic phosphorus, thereby solving the problems of large red phosphorus particles and low activity. 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 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. According to the invention, through high-speed ball milling, phosphorus is doped into the carbon quantum dots, and the carbon quantum dots exist in the form of chemical bonds 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) Preparation of Ni-MOL:
dropwise adding a DMF 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; the mixture is reacted for 9 to 11 hours at the temperature of 115 to 125 ℃, the sediment is obtained by filtration, and the product Ni-MOL with a two-dimensional lamellar structure is obtained by drying.
Preferably, the concentration of terephthalic acid in DMF solution of terephthalic acid is 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 nickel salt in DMF solution of 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 sodium hydroxide solution or potassium hydroxide solution is used to adjust the pH of the solution. The concentration of the solution is 0.035-0.045 mol/L.
Preferably, the drying conditions are: 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 for 9-11 h at 115-125 ℃, and drying the product to obtain the composite photocatalyst (P-CDs/Ni-MOL).
Preferably, the concentration of Ni-MOL in the mixture is 0.015-0.025 g/mL.
According to the invention, the two-dimensional MOFs (Ni-MOL) are used as the carrier to prepare the photocatalyst, the Ni-MOL has the advantages of large specific surface area and more active sites, the surface is of a porous structure, and the 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 Ni loading of 13-16%, P loading of 4-11%, carbon content of 33-40% (at% and atomic number percentage), and the total atomic percentage of C, ni, P, O in the composite photocatalyst is 100%. Preferably, the Ni loading is 14-15%, the P loading is 8-9%, the C content is 36-37% and the O content is 40-41%.
The invention also provides application of the P-CDs/Ni-MOL composite photocatalyst in tetracycline degradation.
The beneficial effects of the invention are as follows:
a) Based on the principle of recycling waste, the composite photocatalyst is prepared by taking low-cost easily-obtained renewable agricultural waste lignin as a carbon source.
b) The method for modifying the carbon quantum dots by combining red phosphorus and mechanical ball milling is creatively adopted in the synthesis method. Compared with other preparation methods, the preparation method avoids the 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 (the removal rate of the tetracycline can still be kept at 91.6% after the composite photocatalyst is 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 cleaning is sustainable. The P-CDs/Ni-MOL composite photocatalyst is used for degrading tetracycline in water, the initial concentration of the tetracycline is 50mg/L, the addition amount of the photocatalyst is 1.0g/L, and the photocatalyst is adsorbed and saturated under dark reaction conditions and is treated with visible light (optical power density: 11mW/cm 2 ) After removal of the tetracycline by irradiation (irradiation time is 120min and removal rate is 98.98%), the tetracycline can be regenerated by washing with ethanol.
Drawings
FIG. 1 is a transmission electron microscope image 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) a transmission electron microscope of P-CD/Ni-MOL; and (d) a high power transmission electron microscope of 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 a composite photocatalytic material.
Fig. 6 is an X-ray photoelectron spectroscopy (XPS) total spectrum of the composite photocatalytic material.
Fig. 7 is an X-ray photoelectron spectrum (XPS) P2P high resolution spectrum of the composite photocatalytic material.
Fig. 8 is a partial enlarged view of P in an X-ray photoelectron spectrum (XPS) total spectrum of the composite photocatalytic material.
FIG. 9 is a graph of photocatalytic degradation of tetracycline by the composite photocatalytic material.
Detailed Description
The following is a further description of the invention, taken in conjunction with the accompanying drawings and specific examples of the invention, and should not be taken as limiting the invention. The lignin is a common commercial product.
Example 1
A preparation method of a carbon quantum dot composite nano photocatalyst,
(1) Preparation of Ni-MOL: terephthalic acid (0.166 g) was mixed into 5mL DMF solution and stirred for 10 minutes to form solution A. Ni (NO) 3 ) 2 (0.436 g) was added to 10mL of DMF solution and stirred for 10 minutes to form solution B. Then, the solution A was added dropwise to the solution B, followed by slowly adding 2mL of 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 and washed with DMF and the collected sample was dried in an oven at 50℃for 12 hours to give the final product (Ni-MOL).
(2) Preparation of carbon quantum dots (P (0) -CDs): 3.0g lignin was added to a ball milling pot, followed by 5mL ethanol and 30 ZrO 2 Ball, set ball milling speed at 800rpm, ball milling for 8h. After ball milling is completed, 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 ℃. 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) Preparation of composite photocatalyst (P-CDs/Ni-MOL): 1.0g Ni-MOL was added to 50mL P (0) -CDs solution and sonicated for 15 minutes. The mixed solution is transferred into a hydrothermal reaction kettle to react for 10 hours at 120 ℃. After natural cooling, the precipitate produced was collected by filtration and washed several times with water and ethanol. The collected sample was dried in a vacuum oven at 60℃for 12 hours, and the obtained sample was a composite photocatalyst, designated as P (0) -CDs/Ni-MOL. The carbon content and the Ni content in the composite photocatalyst are 40.51 percent and 16.37 percent respectively.
Example 2
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from example 1 in that 3.0g lignin and 0.5g red phosphorus are added into a ball milling tank in the step (2), and other conditions are the same as in example 1. The liquid obtained in the step (2) is phosphorus modified carbon quantum dots, and is marked as (P (0.5) -CDs). The composite photocatalyst obtained was designated 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 example 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 in example 1. The liquid obtained in the step (2) is phosphorus modified carbon quantum dots, and is marked as (P (1) -CDs). The composite photocatalyst is named as P (1) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are 8.52%,36.43% and 14.35%, respectively.
Example 4
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from example 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 in example 1. The liquid obtained in the step (2) is phosphorus modified carbon quantum dots, and is marked as (P (1.5) -CDs). The composite photocatalyst obtained was designated as P (1.5) -CDs/Ni-MOL. The contents of P, carbon and Ni in the composite photocatalyst are 9.43%,35.31% and 13.22%, respectively.
Example 5
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is different from example 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 in example 1. The liquid obtained in the step (2) is phosphorus modified carbon quantum dots, and is marked as (P (2.0) -CDs). The composite photocatalyst obtained was designated as P (2.0) -CDs/Ni-MOL. The P, carbon and Ni contents in the composite photocatalyst are respectively 10.81%,33.29% and 13.02%.
Comparative example 1
A method for preparing a phosphorus-modified carbon quantum dot composite nano photocatalyst, which is different from example 3 in that the method for preparing P-modified carbon quantum dots is different. 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, and mixing the lignin and the deionized water according to the ratio g: mL is 1:10 Stirring at 70deg.C for 30min until the mixture is dispersed uniformly, then maintaining at 180deg.C for 6 hr under 1.6MPa, and stopping heating after the reaction.
Comparative example 2
The preparation method of the phosphorus modified carbon quantum dot composite nano photocatalyst is the same as in example 3, except that red phosphorus and lignin are mixed and ball milling is not performed.
Photocatalytic degradation of tetracycline by composite photocatalyst:
preparing a tetracycline solution with initial concentration of 50mg/L, adding the composite photocatalyst obtained in examples 1-5 and the Ni-MOL composite material obtained in step (1) into the tetracycline solution according to the addition amount of 1.0g/L, adsorbing to saturation (4 hours) under dark reaction condition, and using visible light (optical power density: 11mW/cm 2 ) And (5) irradiating, sampling every 20min, and detecting and analyzing the removal rate of the tetracycline.
Product characterization of the composite photocatalytic material:
FIG. 1 shows Ni-MOL and P-CD/Ni-MOL transmission electron mirrors and high power transmission electron environments. As can be seen from FIGS. 1 (a) and (b), ni-MOL has a two-dimensional layered structure, and the lattice fringes of 0.31nm correspond to the 100 crystal plane of Ni-MOL. The transmission electron microscope and the high power transmission electron microscope of the P-CD/Ni-MOL shown in the figures (c) and (d) are shown in the figures, the P-CD/Ni-MOL is a layered structure, and the P-CDs are uniformly loaded on the Ni-MOL. Wherein the lattice fringes 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 that the combination of P-CDs and Ni-MOL is successful.
FIG. 2 is an EDS spectrum of P (1.0) -CD/Ni-MOL showing a uniform distribution of C, O, ni and P, indicating that P-CDs are uniformly distributed over 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, and (a) and (b) are atomic force microscope images of Ni-MOL and P (1.0) -CD/Ni-MOL, respectively. As can be seen from the figure, after loading the P-CDs, the Ni-MOL surface became rough and irregular spherical particles were clearly observed, which indicated that the P-CDs were semi-mosaic distributed on the Ni-MOL surface.
Shown in fig. 4 are XRD patterns 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 010 and 100 crystal planes, respectively. For CDs, peaks of 8.1 °,22.9 ° and 31.6 ° correspond to the internal lamellar structure of the graphitic phase CDs. P (X) -CD/Ni-MOL (X= 0,0.5,1.0,1.5,2) has both Ni-MOL and CDs characteristic peaks, which indicates that CDs have been successfully loaded onto Ni-MOL. No other characteristic peaks are 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 change the graphite-like lamellar configuration of the carbon quantum dots. As the P doping level increases, the characteristic peak at 31.6 ° shifts to a lower angle, indicating that P is doped into the lattice of CDs, but not forming other species. In the figure, P (0) -CD/Ni-MOL without doped P showed impurity peaks around 58 ° and 38 °, while other P (X) -CD/Ni-MOL doped with phosphorus had no apparent impurity peak. This is probably due to the fact that during hydrothermal process, a small amount of Ni-MOL is decomposed to form nickel hydroxide, and the content is small, and the influence on the photocatalytic effect is negligible.
FIG. 5 shows the infrared 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 benzene rings and carbonyl groups. 1210cm -1 The peaks correspond to characteristic peaks of the C-O bonds. After P is introduced in the CD/Ni-MOL,p (X) -CD/Ni-MOL (X= 0,0.5,1.0,1.5,2) at 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) was found to be 723cm -1 The new peak appearing corresponds to the stretching vibration of the C-P bond. 723cm with increasing P doping amount -1 The peak intensity increases, indicating that P has entered the carbon lattice of CDs rather than PO in the adsorbed state 4 3- In the form of a powder. P enters into the carbon lattice of CDs to form substituted defects to effectively capture photo-generated carriers, thereby being beneficial to separation of electrons and holes and improving the photocatalysis performance.
FIGS. 6-8 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 (FIG. 8) compared to Ni-MOL, which indicates that phosphorus has been successfully doped into CD/Ni-MOL. Fig. 7 shows a P2P high resolution spectrum. It can be seen from the figure that P-CD/Ni-MOL has a distinct P2P peak compared to CD/Ni-MOL, with positions 133.94, 133.45 and 132.87eV corresponding to C-O-P, C-P-O and C-P=O, respectively.
FIG. 9 shows the degradation properties of Ni-MOL and P (X) -CD/Ni-MOL (X= 0,0.5,1.0,1.5,2) for tetracycline under visible light. As can be seen from the graph, the degradation rate of Ni-MOL to tetracycline in 120 minutes was 23.93%. 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 the tetracycline is improved to 47.69 percent. After the carbon quantum dots doped with phosphorus 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 ordered 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 degradation performance of the composite photocatalyst to the tetracycline reaches 98.98% at most within 120 min. And the phosphorus modified carbon quantum dot composite nano photocatalyst obtained in comparative example 1 and comparative example 2 is subjected to an experiment of degrading tetracycline, wherein the degradation rate of the composite photocatalyst obtained in comparative example 1 to the tetracycline is 37.45% within 120 min. The degradation rate of the composite photocatalyst obtained in comparative example 2 to tetracycline is 47.63%. This is because the yield of lignin decomposed into quantum dots is relatively low in an acidic environment, so that the carbon quantum dots loaded on the surface of Ni-MOL are reduced, and the photocatalytic performance is greatly affected. 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 atomic phosphorus is distributed more uniformly. Ball milling also results in conversion of the C-O bonds on the lignin surface to C-O-P, C-P-O. Thereby reducing electron transfer resistance.

Claims (14)

1. The preparation method of the phosphorus modified carbon quantum dots (P-CDs) is characterized by comprising the following steps:
mixing lignin and red phosphorus in a mass ratio of 1-10:1, adding ethanol, ball milling for 5-10 hours at a ball milling speed of 800-900 rpm to obtain a ball-milled mixed material; mixing the mixed material and sodium hydroxide according to the mass ratio of 60-70:1, performing hydrothermal reaction for 4-6 hours at 175-185 ℃, and centrifuging the hydrothermal product to obtain liquid, namely the phosphorus-modified carbon quantum dots.
2. The preparation method of claim 1, wherein the mass ratio of lignin to red phosphorus is 1.5-6:1.
3. The preparation method of claim 1, wherein the mass ratio of the added volume of the ethanol to the lignin is 1-2 mL/g.
4. The preparation method of claim 1, wherein the solvent in the hydrothermal reaction is water, and the mass ratio of the volume of the solution to the mass sum of the mixed material and sodium hydroxide is 20-25 mL/g.
5. The method according to claim 1, wherein the ball milling uses ZrO 2 The number of the balls is 25-35.
6. The preparation method of the phosphorus-modified carbon quantum dot composite nano photocatalyst is characterized by adding Ni-MOL into the P-CDs prepared by the method of any one of claims 1-5 for hydrothermal reaction.
7. The preparation method of claim 6, wherein the Ni-MOL is added into the P-CDs to obtain a mixture, the mixture is subjected to ultrasonic dispersion, the mixture is subjected to hydrothermal reaction for 9-11 h at 115-125 ℃, and the product is dried to obtain the P-CDs/Ni-MOL composite photocatalyst.
8. The method of claim 7, wherein the concentration of Ni-MOL in the mixture is 0.015-0.025 g/mL.
9. The preparation method according to claim 6 or 7, wherein the preparation method of Ni-MOL is as follows:
dropwise adding a DMF 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 for 9-11 h at 115-125 ℃, filtering to obtain a precipitate, and drying to obtain the product Ni-MOL with the two-dimensional layered structure.
10. The process according to claim 9, wherein the concentration of terephthalic acid in DMF solution of terephthalic acid is 0.03-0.04 g/mL, and the nickel salt is selected from Ni (NO 3 ) 2 、NiCl 2 、NiSO 4 One or more of the following; the concentration of the nickel salt in the DMF solution of the nickel salt is 0.04-0.05 g/mL.
11. The method according to claim 10, wherein the concentration of terephthalic acid in the DMF solution of terephthalic acid is 0.03-0.035 g/mL; the concentration of the nickel salt in the DMF solution of the nickel salt is 0.04-0.045 g/mL.
12. The P-CDs/Ni-MOL composite photocatalyst prepared by the method of any one of claims 7-8, which 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.
13. The composite photocatalyst of claim 12, wherein the P-CDs/Ni-MOL composite photocatalyst has a Ni loading of 13-16%, a P loading of 4-11%, a carbon content of 33-40%, and a total of C, ni, P, O atomic percent of the composite photocatalyst is 100%.
14. The use of the P-CDs/Ni-MOL composite photocatalyst prepared by the method of any one of claims 6 to 8 in the degradation of tetracycline.
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CN116693581B (en) * 2022-12-31 2024-06-18 深圳中农秸美科技股份有限公司 Method for depolymerizing lignin by visible light catalysis
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Citations (9)

* 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
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
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

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170050851A1 (en) * 2015-08-18 2017-02-23 Transfert Plus, Société En Commandite Method for manufacturing carbon quantum dots
US20210370309A1 (en) * 2020-06-02 2021-12-02 Boise State University Alloys of Black Phosphorus by Ball Milling Techniques

Patent Citations (9)

* 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
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
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

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