Three-dimensional carbon nanocomposite material bonded with single-atom copper, preparation method and application thereof

Abstract

This case involves a three-dimensional carbon nanocomposite bonded with single-atom copper, its preparation method and application. A hyperdispersant is added to water and stirred to dissolve, then GNP and CNT are added. After rapid stirring and uniform dispersion, it is sanded; CNT is continuously added in portions and ground to obtain a GNP / CNT aqueous nano-slurry. An aqueous copper salt solution is added thereto, and after stirring for 1 h, it is vacuum dried and pulverized to obtain a composite nano-powder; it is carbonized in an inert gas to obtain a Cu-GNP / CNT composite nano-powder. In the present invention, graphene and carbon nanotubes form a three-dimensional carbon nano-network, which has an ultra-high specific surface area and excellent electron conduction ability, and can bond single-atom copper with a high loading capacity; thereby activating O2, and having a very wide application prospect in the fields of organic matter degradation and catalytic chemical reactions; it has application potential in the field of non-enzymatic glucose sensors.

Description

Technical Field

[0001] The invention relates to the field of metal single atom / carbon nanocomposite materials, and in particular to a three-dimensional carbon nanocomposite material bonded with single atom copper, and a preparation method and application thereof. Background Art

[0002] Glucose sensor is one of the most widely used biosensors and plays a very important role in the diagnosis and treatment of diabetes. In the prior art, graphene-loaded copper nanoparticles are usually used to prepare non-enzymatic glucose sensors, which can overcome the instability defects of enzyme glucose sensors. For example, Chinese patent 201910030193.8 uses an electrochemical reduction method to prepare graphene-loaded copper nanoparticles, and CN 111999360 B uses an electrochemical reduction method to prepare a graphene film / two-dimensional layered structure compound / copper nanoparticle outer layer composite material. The size of the obtained copper nanoparticles is 100-400nm, and the loading amount of copper nanoparticles is 0.1-0.5mg / g. Through the synergistic conductivity and large specific surface area graphene function, copper nanoparticles show excellent electrocatalytic sensing activity, but compared with single-atom copper, its catalytic activity is much inferior, and the application effect is greatly reduced compared with single-atom metals.

[0003] Compared with homogeneous catalysts, single metal atoms fixed on a carrier have the highest atomic efficiency, excellent catalytic performance, and are easy to separate, thus attracting great attention. However, due to their large specific surface energy and easy migration and agglomeration, there are many challenges in effectively stabilizing the atomic dispersion of single atoms. Summary of the invention

[0004] In view of the deficiencies in the prior art, a three-dimensional carbon nanomaterial formed by graphene and carbon nanotubes bonded with single-atom copper to form a carbon nanocomposite material is provided, which can be used to prepare a non-enzymatic glucose sensor.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a three-dimensional carbon nanocomposite material bonded with single-atom copper comprises the following steps:

[0007] Step 1: Add the hyperdispersant to water and stir to dissolve, add GNP and CNT, stir quickly to disperse evenly, and then sand grind for 3-7 hours; continue to add CNT in batches, grind for 8-10 hours, and obtain GNP / CNT aqueous nanoslurry;

[0008] Step 2: Dissolve the copper salt in water and add it to the GNP / CNT aqueous nanoslurry prepared in step 1, stir for 1 hour, and obtain Cu 2 + / GNP / CNT aqueous nanoslurry;

[0009] Step 3: Vacuum drying of the Cu prepared in step 2 2+ / GNP / CNT aqueous nanoslurry, after crushing, Cu 2+ / GNP / CNT composite nanopowder;

[0010] Step 4: Carbonizing the Cu in an inert gas 2+ / GNP / CNT composite nanopowder is obtained by heating to 950-1050°C at a rate of 5°C / min and carbonizing for 1-1.5h, which is recorded as Cu-GNP / CNT.

[0011] Furthermore, the hyperdispersant is DC-P, and the structural formula is

[0012] Furthermore, the dosage of the hyperdispersant is 0.75-1.5% of the total mass of GNP and CNT, and the mass ratio of GNP to CNT is 8:1-16:1.

[0013] Furthermore, the solid content of the GNP / CNT aqueous nanoslurry is 15-20%.

[0014] Furthermore, the copper salt is at least one of copper sulfate, copper chloride and copper nitrate, wherein the mass of copper is 1-2% of the total mass of GNP and CNT.

[0015] The present invention further provides a three-dimensional nanocomposite material of bonded single-atom copper obtained by the preparation method as described above.

[0016] The present invention further provides a use of the three-dimensional nanocomposite material bonded with single-atom copper as described above in a non-enzymatic glucose sensor.

[0017] The Cu-GNP / CNT prepared by the present invention uses a three-dimensional carbon nanomaterial formed by graphene (GNP) and carbon nanotubes (CNT) as a carrier, and utilizes Cu in a high-temperature inert gas to form a carbon nanomaterial. 2+ The Cu-GNP / CNT nanocomposite material is reduced and enters the defective lattice of the carbon nanomaterial, thereby forming a single-atom Cu bonded to the GNP / PANI three-dimensional carbon nanostructure to form a Cu-GNP / CNT nanocomposite material; the three-dimensional structured carbon nanomaterial has a large specific surface area and can bond single-atom copper at a high loading; the three-dimensional structured carbon nanomaterial has excellent electronic conductivity, which can greatly improve the electrocatalytic activity of Cu-GNP / CNT and has application potential in the field of non-enzymatic glucose sensors. In addition, the Cu-GNP / CNT in this case not only exhibits excellent electrocatalytic activity characteristics, but also has certain antimicrobial properties. Specifically, the single-atom Cu in Cu-GNP / CNT will lead to oxygen vacancies on the interface, which helps to activate oxygen; the use of single-atom copper can effectively catalyze the surrounding oxygen and water to form superoxide and The product exhibits high antimicrobial activity by removing free radicals; the preparation method is simple and green, the cost is low, it can be prepared on an industrial scale, and the product has good stability.

[0018] The beneficial effects of the present invention are:

[0019] 1) Graphene and carbon nanotubes form a three-dimensional carbon nanonetwork with an ultra-high specific surface area and excellent electron conductivity, which can bond single-atom copper with high loading capacity;

[0020] 2) The copper ions are uniformly adsorbed on the surface of the GNP / CNT three-dimensional carbon nanomaterial through electrostatic interaction with the negative charges in the superdispersant on the surface of the three-dimensional carbon nanomaterial;

[0021] 3) During high-temperature carbonization, copper ions are reduced and tend to bond to defect sites in the three-dimensional carbon nanocrystal lattice, thereby obtaining a nanocomposite material with a stable structure of three-dimensional carbon nanomaterials bonded to single-atom copper (Cu-GNP / CNT);

[0022] 4) Single-atom Cu in Cu-GNP / CNT will lead to oxygen vacancies on the interface, which helps to activate oxygen, making it have very broad application prospects in the fields of organic matter degradation and catalytic chemical reactions. At the same time, the synergistic effect of single-atom copper and three-dimensional carbon nanonets greatly enhances the electrocatalytic activity, making it have potential for application in the field of non-enzymatic glucose sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 (a) TEM image of experimental sample 1 at a lower magnification; (b) TEM image at a higher magnification; (c) HrTEM image; (d) diffraction pattern corresponding to (c).

[0024] Figure 2 HAADF-STEM and elemental mapping of experimental sample 1.

[0025] Figure 3 This is the Raman spectrum of experimental sample 1.

[0026] Figure 4 (a) TEM image of experimental sample 2 at a lower magnification; (b) TEM image of experimental sample 2 at a higher magnification.

[0027] Figure 5 (a, b) are the TEM image and HrTEM image of the control sample, respectively.

[0028] Figure 6 This is the redox reaction activity diagram of experimental sample 1.

[0029] Figure 7 Fluorescence microscopy image of the coating's resistance to diatom attachment.

[0030] Figure 8 The cyclic voltammetry curve.

[0031] Fig. 9 This is the current-time response curve of Cu-GNP / CNT as a glucose sensor. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] A method for preparing a three-dimensional carbon nanocomposite material bonded with single-atom copper comprises the following steps:

[0035] Step 1: Add the hyperdispersant (DC-P) into water and stir to dissolve, add GNP and part of CNT, disperse at a speed of 1500r / min for 10-15 minutes; sand grind for 3-7 hours; add the remaining CNT in batches, continue grinding until the fineness and viscosity meet the requirements, the total grinding time is 8-10 hours, and obtain graphene / carbon nanotube (GNP / CNT) aqueous nanoslurry.

[0036] Step 2: Dissolve the copper salt in water and add it to the graphene / carbon nanotube aqueous nanoslurry prepared in step 1, and stir at a speed of 1000 r / min for 1 hour to obtain a copper salt uniformly dispersed on the surface of the graphene / carbon nanotubes (Cu 2+ / GNP / CNT) aqueous nanoslurry.

[0037] Step 3: Vacuum drying of the Cu prepared in step 2 2+ / GNP / CNT aqueous nanoslurry, after crushing, Cu 2+ / GNP / CNT composite nanopowder.

[0038] Step 4: Carbonize the composite nanopowder, raise the temperature to 950-1050°C at 5°C / min, and carbonize for 1-1.5 hours. The carbonization atmosphere is at least one of nitrogen or argon.

[0039] In this case, super dispersant (DC-P) The other reagents were purchased from Yangzhou Yilite Polymer Material Technology Co., Ltd.

[0040] The above method is used to prepare a series of products, as follows:

[0041] Example 1

[0042] 2.55 g of superdispersant DC-P was added to 1100 g of water and stirred to dissolve, and then 240 g of graphene nanosheets and 7 g of carbon nanotubes were added, and the mixture was dispersed at a speed of 1500 r / min for 10-15 minutes and sand-milled for 4 hours; the remaining 8 g of carbon nanotubes were added and the mixture was further ground for 6 hours to obtain graphene / carbon nanotube nano-water-based nano-slurry;

[0043] Dissolve 9.96 g of CuSO4·5H2O in 180 g of water to form a CuSO4 aqueous solution, and then add it to the graphene / carbon nanotube nano aqueous nano slurry; stir at a speed of 1000 r / min for 1 hour to achieve uniform mixing;

[0044] The nanocomposite slurry is vacuum dried and crushed to obtain copper sulfate / graphene / carbon nanotube uniformly dispersed composite powder;

[0045] Carbonize the composite powder: heat up to a carbonization temperature of 1000°C at a rate of 5°C / min and carbonize for 1 hour.

[0046] The experimental sample 1 was obtained: Cu (1%)-GNP (93.2%) / CNT (5.8%).

[0047] Depend on Figure 1 (a) It can be seen that CNTs are evenly distributed on the surface of the GNP nanosheets. In the magnified TEM image (1b), it can be clearly seen that the binary GNP nanosheets and the one-dimensional CNT carbon nanotubes form a three-dimensional network structure. Figure 1 (c) is the HrTEM image, in which we can see that CNTs are evenly dispersed on the GNP nanosheets, and the CNT wall thickness is about 3-4 nm. Figure 1 (d) The strong crystalline diffraction peaks formed by GNPs and CNTs can be clearly seen.

[0048] Figure 2 These are the HAADF-STEM and elemental mapping images of the nanocomposite. In the elemental mapping of the nanocomposite, we can see that "C" and "Cu" are evenly distributed. Combined with the fact that no copper nanoparticles are observed in the HrTEM image, this result indicates that copper is bonded in the three-dimensional carbon nanomaterial lattice in the form of single atoms.

[0049] Figure 3 This is the Raman spectrum of experimental sample 1, 1580cm -1 The G characteristic peak of CNT and GNP is 1353cm -1The D characteristic peak of CNT and GNP is at the center. The bonding of copper has no significant effect on the Raman spectrum of GNP / CNT. This is because the mass content of single atomic copper accounts for only 1-2% of the total mass of GNP / CNT.

[0050] Embodiment 2:

[0051] 0.18 g of superdispersant DC-P was added to 130 g of water and stirred to dissolve, and then 32 g of graphene nanosheets and 2 g of carbon nanotubes were added, and dispersed at a speed of 1500 r / min for 10-15 minutes. After sand grinding for 3-4 hours, the remaining 2 g of carbon nanotubes were added twice according to the viscosity of the system, and the total grinding time was 10 hours to obtain graphene / carbon nanotube nano water-based nano slurry;

[0052] Dissolve 2.72 g of Cu(NO3)2·3H2O in 25 g of water to form a Cu(NO3)2 aqueous solution, and then add it to the graphene / carbon nanotube nano aqueous nano slurry; stir at a speed of 1000 r / min for 1 hour to achieve uniform mixing;

[0053] The nanocomposite slurry is vacuum dried and crushed to obtain a copper nitrate / graphene / carbon nanotube uniformly dispersed composite powder;

[0054] Carbonize the composite powder: heat up to a carbonization temperature of 950°C at a rate of 5°C / min and carbonize for 1.5 h.

[0055] The experimental sample 2 was obtained: Cu (2%)-GNP (87.1%) / CNT (10.9%).

[0056] like Figure 4 This is the TEM image of experimental sample 2. From this, we can see the three-dimensional carbon nanostructure of Cu(2%)-GNP(87.1%) / CNT(10.9%), and no copper nanoparticles are observed, indicating that copper is also bonded in the three-dimensional carbon nanomaterial lattice in the form of single atoms.

[0057] Comparative Example 1

[0058] 2 g of hyperdispersant DC-P was added to 900 g of water and stirred to dissolve, and then 200 g of graphene nanosheets were added, and dispersed at a speed of 1500 r / min for 10-15 minutes, and sand-milled for 8 hours to obtain graphene aqueous nanoslurry;

[0059] Dissolve 7.8 g of CuSO4·5H2O in 100 g of water to form a CuSO4 aqueous solution, and then add it to the above graphene aqueous nanoslurry; stir at a speed of 1000 r / min for 1 hour to achieve uniform mixing;

[0060] The nanocomposite slurry is vacuum dried and crushed to obtain copper sulfate / graphene uniformly dispersed composite powder;

[0061] Carbonize the composite powder: heat up to a carbonization temperature of 1000°C at a rate of 5°C / min and carbonize for 1 hour.

[0062] The comparative sample was obtained: Cu(1%)-GNP(99%).

[0063] Figure 5 (a, b) are the TEM and HrTEM images of the comparison sample, respectively. It can be seen that the graphene surface is adsorbed with hyperdispersant molecules, and no nanoparticles are observed on the binary nanosheets, indicating that copper is bonded in the graphene lattice in atomic form.

[0064] application:

[0065] 1. Comparison of oxygen reduction (ORR) activity between experimental sample 1 and control sample

[0066] The LSV electrocatalytic activities of Cu-GNP and Cu-GNP / CNT catalysts for ORR were compared in 0.1 mol / L NaOH solution under O2 saturation and at a rotation rate of 1600 r / min.

[0067] like Figure 6 As shown, compared with the Cu-GNP prepared in Comparative Example 1, the Cu-GNP / CNT catalyst prepared in Example 1 shows higher ORR electrocatalytic activity in terms of the most positive half-wave potential (E1 / 2) and the starting potential (Eonset), which are 0.73V and 0.883V respectively, both of which are comparable to the voltages of the same type of ORR catalysts. This is because the three-dimensional carbon nanocarrier has a larger surface than the two-dimensional nanosheet 1) which accelerates the transport of molecules and makes it easier to contact the active sites; 2) has better electrical conductivity, which is conducive to the improvement of ORR activity.

[0068] 2. Anti-diatom and antibacterial performance test:

[0069] The experimental sample 1 and the control sample were added to acrylic polyurethane coating (purchased from Jiangsu Huaxia Paint Technology Co., Ltd., model: PU700-J), and the addition amount was 0.5% of the solid mass. After sanding process, nano slurry was formed and then evenly mixed with PU700-J coating. After drying at room temperature, a nano-composite coating (coating thickness 60 μm) was formed and anti-diatom tests were carried out.

[0070] 1. Anti-diatom test: cultured diatoms were selected to test different coating samples in a constant temperature incubator at 23°C. After 3 days, the samples were taken out and gently rinsed with saline. Then, they were observed under a fluorescence microscope, 20 photos were selected, and statistics were performed using ImageJ software.

[0071] Figure 7As a result of the above test, it can be seen that the coating obtained by using the Cu-GNP / CNT nanocomposite prepared by the present invention as a functional additive has excellent anti-diatom adhesion performance. The red part represents the fluorescence of diatoms. The spherical algae under the fluorescence microscope, the control sample has no anti-diatom property, and the composite coating of the experimental sample has good diatom antifouling ability, indicating that the Cu-GNP / CNT nanocomposite has excellent anti-diatom adhesion activity.

[0072] 2. Antibacterial test

[0073] Table 1

[0074]

[0075] In Table 1, the control group is a coating without Cu-CNT / GNP addition; the experimental group is a coating with 0.5wt% Cu-CNT / GNP addition, and the antibacterial performance R = LgC 24h，对照组 -LgC 24h，实验组 The results in Table 1 show that compared with the coating without Cu-CNT / GNP, the nanocomposite coating with 0.5wt% Cu-CNT / GNP significantly reduced the bacterial concentration after 24 hours. Moreover, the antibacterial performance R is greater than or equal to 2, indicating that the antibacterial rate of the coating material without Cu-CNT / GNP is greater than 99%; and the coating material with Cu-CNT / GNP has better antibacterial performance against Staphylococcus aureus than Escherichia coli.

[0076] 3. The electrocatalytic oxidation performance of the modified electrode on glucose was studied by cyclic voltammetry and current-time curve method.

[0077] A three-electrode method was used, with a platinum electrode as the counter electrode, a calomel electrode as the reference electrode, a nanomaterial-modified glassy carbon electrode as the working electrode, and a 0.1 M NaOH solution as the electrolyte.

[0078] Figure 7 The cyclic voltammetry (CV) diagram of the glassy carbon electrode modified with the Cu-GNP / CNT prepared in Example 1 and the Cu-GNP nanocomposite prepared in Comparative Example 1 was tested for 20 mM glucose in 0.1 M NaOH solution. Compared with Cu-GNP, the oxidation current of Cu-GNP / CNT increased by more than 2 times. This result indicates that the single-atom copper bonded to three-dimensional carbon nanotubes has better glucose oxidation electrocatalytic activity than the single-atom copper bonded to two-dimensional graphene.

[0079] The Cu-GNP / CNT prepared in Example 1 was further used as a glucose electroanalysis sensor material, the potential was kept constant at 0.50 V, and the current-time measurement method ( Fig. 9), and it was found that when the glucose concentration was in the range of 0.01mM-0.48mM, the current was linearly related to the glucose concentration: I = 1.70294×10-6 + 2.3089×10-5×C (R is 0.995). Therefore, Cu-GNP / CNT is a potential electrocatalytic oxidation sensing material for non-enzymatic glucose concentration detection, which is suitable for the determination of glucose concentration in sweat, saliva and beverages.

[0080] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a three-dimensional carbon nanocomposite material bonded with single-atom copper, characterized in that: The steps include: Step 1: Add the hyperdispersant to water and stir to dissolve, add GNP and CNT, stir quickly to disperse evenly, and then sand grind for 3-7 hours; continue to add CNT in batches, grind for 8-10 hours, and obtain GNP / CNT aqueous nanoslurry; Step 2: Dissolve the copper salt in water and add it to the GNP / CNT aqueous nanoslurry prepared in step 1, stir for 1 h to obtain Cu 2+ / GNP / CNT aqueous nanoslurry; Step 3: Vacuum drying of the Cu prepared in step 2 2+ / GNP / CNT aqueous nanoslurry, after crushing, Cu 2+ / GNP / CNT composite nanopowder; Step 4: Carbonizing the Cu in an inert gas 2+ / GNP / CNT composite nanopowders are heated to 950-1050 °C at 5 °C / min for 1-1.5 h to obtain; The amount of the hyperdispersant is 0.75-1.5% of the total mass of GNP and CNT, and the mass ratio of GNP to CNT is 8:1-16:1; the solid content of the GNP / CNT aqueous nanoslurry is 15-20%; the hyperdispersant is DC-P, and the structural formula is 。 2. The method for preparing the three-dimensional carbon nanocomposite material bonded with single-atom copper according to claim 1, characterized in that: The copper salt is at least one of copper sulfate, copper chloride and copper nitrate, wherein the mass of copper is 1-2% of the total mass of GNP and CNT.

3. A three-dimensional carbon nanocomposite material bonded with single-atom copper obtained by the preparation method according to claim 1 or 2.

4. The use of the three-dimensional carbon nanocomposite material bonded with single-atom copper as claimed in claim 3, characterized in that: Used for the preparation of non-enzymatic glucose sensors or antimicrobial coatings.

Images