Multi-carbon-layer loaded metal atom material and preparation method thereof
By using the carbon layer of the multi-walled carbon nanotube itself to build a carbon cladding layer and using the metal nanoparticles inside it as a metal source, a high-stability multi-carbon layer-loaded metal atomic material is prepared, which solves the problems of insufficient stability and high manufacturing cost of metal atomic materials in the prior art, and achieves high stability and large-scale application potential of the material.
Patent Information
- Application Number
- CN202510034576.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2025-04-01
AI Technical Summary
There are shortcomings in existing metal atomic materials in terms of stability and large-scale applications, especially due to the attenuation of the stability of metal-heteroatom bonds, the performance of materials is attenuated, and the existing carbon coating methods have poor crystallinity and electrical conductivity, making it difficult to improve the stability of materials and promote them on a large scale.
By constructing a carbon cladding layer using the highly conductive carbon layer of the multi-walled carbon nanotube itself and using the metal nanoparticles within it as a metal source, a high-stability multi-carbon layer-loaded metal atomic material is prepared through simple mixing and heat treatment steps.
It achieves high stability of the material structure, simplifies the synthesis process, reduces manufacturing costs, has cost advantages and large-scale application potential.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
Technical Field
[0001] The invention belongs to the field of inorganic nanomaterials, and in particular relates to a multi-carbon layer loaded metal atom material and a preparation method thereof. Background Art
[0002] Materials containing atomically dispersed metals, namely metal atomic materials, have the characteristics of high utilization rate of metal atoms and diversified distribution of valence electron clouds. They are an emerging functional nanomaterial that has flourished in recent years and have broad application prospects in the fields of light, electricity, magnetism, heat, chemistry, biochemistry, etc. Multi-walled carbon nanotubes have become one of the most common metal atomic material substrates due to their advantages such as high mechanical strength, high chemical stability and high conductivity. Even so, due to the large changes in the electron cloud distribution of atomically dispersed metals that rely on the stable metal-heteroatom-carbon bond structure, while their intrinsic activity is greatly improved, the stability of the metal-heteroatom bond is attenuated, resulting in the attenuation of material performance, which is not conducive to large-scale promotion and application.
[0003] To improve the stability of metal atomic materials, an effective method that has been explored is to modify the second coordination circle of the metal with specific heteroatoms (Nature 2019, 575, 639-642). However, this method is not only difficult to design, but also difficult to accurately synthesize, which is not conducive to large-scale promotion and application. Carbon coating is a structure that effectively improves the stability of metal nanomaterials. It usually uses carbon sources such as glucose to mix with metal nanoparticles and then heat treat them to form a carbon coating on the surface of metal nanoparticles. By adjusting the dosage ratio of carbon source to metal nanoparticles, the thickness of the outer carbon layer can be optimized to reduce the impact on the internal metal nanoparticles as functional sites. However, this carbon coating usually has poor crystallinity and poor conductivity, and it is inevitable to have adverse effects. If the carbon coating structure can be constructed using the tube wall of multi-walled carbon nanotubes itself, it can not only directly utilize the inherent high crystallinity and high conductivity of carbon nanotubes to improve the stability of metal atomic materials based on multi-walled carbon nanotubes, but also simplify the synthesis process to prepare multi-carbon layer-loaded metal atomic materials with carbon coating structures, saving reagents and manufacturing costs, which is conducive to improving its stability and large-scale application potential. However, there have been no reports on this so far. Summary of the invention
[0004] The purpose of the present invention is to propose a multi-carbon layer loaded metal atom material and a simple and efficient preparation method thereof. The invention innovatively proposes to use the highly conductive carbon layer of multi-walled carbon nanotubes to construct a carbon coating layer, and use the metal nanoparticles contained therein as a metal source, and obtain a highly stable multi-carbon layer loaded metal atom material through simple mixing and heat treatment steps. The simple and inexpensive preparation method is used to solve the problems of poor stability and high manufacturing cost of metal atom materials, which is more conducive to actual production and application.
[0005] According to the first aspect of the present invention, the present invention provides a multi-carbon layer loaded metal atom material, wherein the multi-walled carbon nanotube is a carbon substrate loaded metal, the metal is dispersed in the form of atoms, and the dispersed position includes multiple layers of carbon tubes including the inner layer carbon tube.
[0006] According to a second aspect of the present invention, the present invention provides a method for preparing a multi-carbon layer-loaded metal atom material, comprising the following steps: Step 1: fully mix the multi-walled carbon nanotubes, the coordination element source material and the fluorine source material; Step 2: placing the mixture obtained in step 1 in an oxygen-free atmosphere for heat treatment to obtain a multi-carbon layer loaded metal atom material.
[0007] The purity of the multi-walled carbon nanotubes is not less than 75%, the thickness of the tube wall is not less than 1 nm; the metal residue is not less than 0.1wt%, and the metal type is one or a combination of iron, cobalt, nickel, manganese, copper, zinc, lanthanum, yttrium, scandium, europium, gadolinium, samarium, neodymium, cerium, and praseodymium.
[0008] In the step 1, the nitrogen source is urea, melamine, dicyandiamide, thiourea, polyethyleneimine, cyanuric chloride, polypyrrole, terpyridine, glycine, o-aminoazotoluene, bipyridine, o-phenanthroline, L-alanine, polyaniline, glutamic acid, tris(hydroxymethyl)aminomethane, cysteine, carrageenan, diphenyl disulfide, ammonium sulfide, thioacetamide, thiocarbonate, 4,4'-dihydroxydiphenyl sulfone, diphenyl thiocarbonate, 3,3'-thiodipropionic acid, triphenylphosphine, 1,3-nitrophosphorene, triethyl phosphite, phenylphosphonic acid, phosphoramide, phosphazene, boric acid, ferrocene boric acid, 1,4-phenylenediboric acid, boron phosphide, boronized carbon, or a combination thereof; the fluorine source is polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluorinated ethylene propylene copolymer (FEP), polyvinyl ... F), polychlorotrifluoroethylene (PCTFE), 4-fluorophenol, 4-fluorosalicylic acid, 2,4-difluorobenzoic acid, 3-fluoroacetic acid, 4-fluorophenylacetic acid, tetrafluoroterephthalonitrile, tetrafluoroterephthalaldehyde, polytetrafluoroethylene-ethylene copolymer (ETFE), vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene terpolymer, vinylidene fluoride-tetrafluoroethylene-perfluoromethyl vinyl ether-sulfurization point monomer quaternary copolymer, tetrafluoroethylene and hydrocarbon propylene copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, ammonium fluorosilicate, perfluorosulfonic acid monomer, perfluoroalkoxy resin, ammonium fluoride, ammonium hydrogen fluoride, xenon fluoride, zinc fluoride, sodium fluoride, potassium fluoride, barium fluoride, calcium fluoride, lithium fluoride, rubidium fluoride, silver fluoride, nickel fluoride, cobalt fluoride, ammonium fluorotitanate, one or more combinations thereof.
[0009] The mixing in step 1 is one or a combination of grinding mixing, ball milling mixing, magnetic stirring mixing, and vortex mixing.
[0010] The oxygen-free atmosphere in step 2 is one or a combination of helium, nitrogen, ammonia, hydrogen and argon.
[0011] The heat treatment temperature in step 2 is 600-1800°C, and the heating rate is 1-10°C·min -1 , constant temperature time is 0.5-10 h.
[0012] The multi-carbon layer loaded metal atom material prepared by the preparation method has a tube wall thickness of not less than 0.6 nm, and the metal atoms are dispersed in the multi-layer carbon tubes.
[0013] The beneficial effects of the present invention are embodied in: (1) The material structure has high stability, which is conducive to promotion and application. The multi-carbon layer-loaded metal atom material provided by the present invention uses the highly crystalline and highly conductive carbon tube layer of the multi-walled carbon nanotube itself to construct a carbon coating structure, and uses the metal remaining inside the multi-walled carbon nanotube during synthesis as a metal source to manufacture atomic-level distributed metal, thereby forming a multi-carbon layer-loaded metal atom material and improving its stability. In contrast, when single-walled carbon nanotubes are used as a substrate to synthesize metal atom materials, the atomic-level distributed metals are all exposed on the surface of the only carbon layer, and the metal single atoms are prone to poisoning, shedding and agglomeration. When graphene is used as a substrate to synthesize metal atom materials, not only the above problems need to be faced, but also the problem of graphene's easy agglomeration and deactivation needs to be solved. Therefore, the multi-carbon layer-loaded metal atom material provided by the present invention is more conducive to large-scale promotion and application.
[0014] (2) The raw materials are cheap and the synthesis process is simple, which is conducive to large-scale production. The price of multi-walled carbon nanotubes containing significant (0.1wt%~3wt%) metals applicable to the present invention (500 yuan / kg) is less than one-tenth of the price of high-purity multi-walled carbon nanotubes (9000 yuan / kg). In addition, multi-walled carbon nanotubes do not require pretreatment, and the metals remaining during the synthesis of multi-walled carbon nanotubes are directly used as metal sources to manufacture atomic-level distributed metal structures, which simplifies the process and reduces the cost of using reagents. In contrast, the method of modifying the second coordination circle of the metal with specific heteroatoms is not only difficult to design, but also difficult to accurately synthesize, which is not conducive to large-scale promotion and application. Therefore, the multi-carbon layer-loaded metal atom material and the synthesis method thereof provided by the present invention have cost advantages and are conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a transmission electron microscope image of the commercially available multi-walled carbon nanotubes used in Examples 1-2.
[0016] Figure 2This is a scanning transmission electron micrograph of the multi-carbon layer-loaded metal atom material prepared in Example 1.
[0017] Figure 3 This is the element distribution diagram of the multi-carbon layer loaded metal atom material prepared in Example 1.
[0018] Figure 4 High-resolution X-ray photoelectron spectroscopy (Ni 2p) of the commercially available multi-walled carbon nanotubes and the prepared multi-carbon layer-supported metal atom materials used in Example 1.
[0019] Figure 5 High-resolution X-ray photoelectron spectroscopy (N 1s) of the commercially available multi-walled carbon nanotubes used in Example 1 and the prepared multi-carbon layer-supported metal atom material.
[0020] Figure 6 This is a graph showing the experimental results of the thiocyanate resistance of the multi-carbon layer-loaded metal atom material prepared in Example 1. DETAILED DESCRIPTION
[0021] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. The following content is only an example and explanation of the concept of the present invention. The technicians in the field may make various modifications or supplements to the specific implementation cases described, or replace them with similar methods, as long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention. Example 1
[0022] A preparation method of a multi-carbon layer loaded metal atom material comprises the following steps: Step 1: Weigh 1 g of multi-walled carbon nanotubes with a purity of 90% and a Ni metal residue of 1 wt%, 10 g of urea, and 5 g of PTFE, and grind them thoroughly to obtain a mixed powder; Step 2: The mixed powder obtained in step 1 was heated in an argon atmosphere at a temperature of 800°C and a heating rate of 5°C·min -1 , the heating time is 1 h, and a multi-carbon layer loaded metal atom material is obtained.
[0023] The transmission electron microscope image of the commercially available multi-walled carbon nanotubes used in this example is as follows: Figure 1 As shown in the figure, the thickness of the tube wall is about 12 nm, and the cavity contains a large number of large-sized metal nanoparticles; the scanning transmission electron microscopy image of the obtained multi-carbon layer loaded with metal atoms is shown in Figure 2 As shown, no large-sized metal nanoparticles are found, and the metal is distributed at the atomic level; its element distribution diagram is shown in Figure 3 As shown, the Ni element is evenly distributed throughout the entire diameter of the carbon tube. Figure 4This is the Ni 2p fine X-ray photoelectron spectrum of the commercial multi-walled carbon nanotube raw material and the obtained multi-carbon layer loaded metal atom material, with a detection depth of 10 nm. It can be seen that the commercial multi-walled carbon nanotubes did not measure the Ni signal because its Ni signal was blocked by the multi-layer carbon nanotubes with a wall thickness of 12 nm, while the obtained multi-carbon layer loaded metal atom material measured an obvious Ni signal, indicating that Ni was dispersed into the multi-layer tube wall and entered the detection range of XPS. Figure 5 This is the N 1s fine X-ray photoelectron spectrum of the commercially available multi-walled carbon nanotube raw material and the obtained multi-carbon layer-loaded metal atom material. Similarly, no N signal was measured in the commercially available multi-walled carbon nanotubes, while an obvious N signal was measured in the obtained multi-carbon layer-loaded metal atom material. The fitting diagram shows that a Ni-N bond structure is formed.
[0024] Thiocyanate has a strong masking effect on metals exposed on the surface of the material, and is used to examine whether the multi-carbon layer-loaded metal atom material prepared by the present invention has a carbon-coated structure and high stability. In an H-type electrolytic cell, the catalyst in this embodiment is used as a cathode catalyst and loaded on a gas diffusion layer substrate to obtain a cathode; a platinum sheet is used as an anode, a silver / silver chloride electrode is used as a reference electrode, and the electrolyte is a 0.5 M KHCO3 aqueous solution containing saturated carbon dioxide. After a period of constant potential electrolysis, 0.385 mL of 8M potassium thiocyanate is added to the electrolyte; then constant potential electrolysis is performed again. The current density of the carbon dioxide reduction product of the two constant potential electrolysis was recorded, and the results are as follows: Figure 6 It can be seen that the addition of potassium thiocyanate does not affect the stability of the multi-carbon layer supported metal atom material, which indicates that the metal atom material prepared by the present invention has a carbon-coated multi-carbon layer supported structure. Example 2
[0025] A preparation method of a multi-carbon layer loaded metal atom material comprises the following steps: Step 1: Weigh 0.5 g of multi-walled carbon nanotubes with a purity of 85% and a Ni metal residue of 0.5 wt%, 10 g of dicyandiamide, and 4 g of PVF, and fully ball-mill them to obtain a mixed powder; Step 2: The mixed powder obtained in step 1 was placed in a nitrogen atmosphere and heated to 850°C at a heating rate of 7°C min. -1 , the heating time is 2.5 h, and a multi-carbon layer loaded metal atom material is obtained.
[0026] The transmission electron microscope image of the commercially available multi-walled carbon nanotubes used in this example is as follows: Figure 1 As shown, the tube wall thickness is about 12 nm, and the cavity contains a large number of large-sized metal nanoparticles. Example 3
[0027] A preparation method of a multi-carbon layer loaded metal atom material comprises the following steps: Step 1: Weigh 1 g of multi-walled carbon nanotubes with a purity of 80% and a cobalt metal residue of 2 wt%, 8 g of thiourea, and 6 g of PVDF, and vortex mix them thoroughly to obtain a mixed powder; Step 2: Heat the mixed powder obtained in step 1 in a helium atmosphere at a temperature of 750 °C, heating rate 6 °C min -1 , the heating time is 3 h, and a multi-carbon layer loaded metal atom material is obtained. Example 4
[0028] A preparation method of a multi-carbon layer loaded metal atom material comprises the following steps: Step 1: Weigh 1 g of multi-walled carbon nanotubes with a purity of 90% and a manganese metal residue of 1 wt%, 5 g of melamine, and 5 g of cobalt fluoride, and mix them by magnetic stirring to obtain a mixed powder; Step 2: Heat the mixed powder obtained in step 1 in a 5% hydrogen / 95% argon atmosphere at a temperature of 1200°C and a heating rate of 3°C·min -1 , the heating time is 5 h, and a multi-carbon layer loaded metal atom material is obtained. Example 5
[0029] A preparation method of a multi-carbon layer loaded metal atom material comprises the following steps: Step 1: Weigh 1 g of multi-walled carbon nanotubes with a purity of 75% and an iron metal residue of 1 wt%, 12 g of triphenylphosphine, and 5 g of vinylidene fluoride-hexafluoropropylene copolymer, and grind them thoroughly to obtain a mixed powder; Step 2: The mixed powder obtained in step 1 was heated in an argon atmosphere at a temperature of 800°C and a heating rate of 5°C·min -1 , the heating time is 1.5 h, and a multi-carbon layer loaded metal atom material is obtained.
Claims
1. A multi-carbon layer loaded metal atom material, characterized in that: Multi-walled carbon nanotubes are carbon substrates loaded with metals, with the metals dispersed in the form of atoms in multiple layers of carbon tubes including the surface and inner carbon tubes.
2. A method for preparing a multi-carbon layer-supported metal atom material as claimed in claim 1, characterized in that: The steps include: Step 1: fully mix the multi-walled carbon nanotubes, the coordination element source material and the fluorine source material; Step 2: placing the mixture obtained in step 1 in an oxygen-free atmosphere for direct heat treatment to obtain a multi-carbon layer loaded metal atom material.
3. The method for preparing a multi-carbon layer-loaded metal atom material according to claim 2, characterized in that: The purity of the multi-walled carbon nanotubes in step 1 is not less than 75%, and the tube wall thickness is not less than 1 nm; the metal residue is not less than 0.1wt%, and the metal type is one or a combination of iron, cobalt, nickel, manganese, copper, zinc, lanthanum, yttrium, scandium, europium, gadolinium, samarium, neodymium, cerium, and praseodymium.
4. The method for preparing a multi-carbon layer-supported metal atom material according to claim 2, characterized in that: Step 1: The coordination element source is urea, melamine, dicyandiamide, thiourea, polyethyleneimine, cyanuric chloride, polypyrrole, terpyridine, glycine, o-aminoazotoluene, bipyridine, o-phenanthroline, L-alanine, polyaniline, glutamic acid, tris(hydroxymethyl)aminomethane, cysteine, carrageenan, diphenyl disulfide, ammonium sulfide, thioacetamide, thiocarbonate, 4,4'-dihydroxydiphenyl sulfone, diphenyl thiocarbonate, 3,3'-thiodipropionic acid, triphenylphosphine, 1,3-nitrophosphorene, triethyl phosphite, phenylphosphonic acid, phosphoramide, phosphazene, boric acid, ferrocene boric acid, 1,4-phenylenediboric acid, boron phosphide, boronized carbon, or a combination thereof; the fluorine source is polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene copolymer, polyvinyl fluoride, polytrifluorochloroethylene, Ethylene, 4-fluorophenol, 4-fluorosalicylic acid, 2,4-difluorobenzoic acid, 3-fluoroacetic acid, 4-fluorophenylacetic acid, tetrafluoroterephthalonitrile, tetrafluoroterephthalaldehyde, polytetrafluoroethylene-ethylene copolymer (ETFE), vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene terpolymer, vinylidene fluoride-tetrafluoroethylene-perfluoromethyl vinyl ether-sulfurization point monomer quaternary copolymer, tetrafluoroethylene and hydrocarbon propylene copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, ammonium fluorosilicate, perfluorosulfonic acid monomer, perfluoroalkoxy resin, ammonium fluoride, ammonium hydrogen fluoride, xenon fluoride, zinc fluoride, sodium fluoride, potassium fluoride, barium fluoride, calcium fluoride, lithium fluoride, rubidium fluoride, silver fluoride, nickel fluoride, cobalt fluoride, ammonium fluorotitanate or a combination of the above.
5. The method for preparing a multi-carbon layer-loaded metal atom material according to claim 2, characterized in that: The mixing in step 1 is one or a combination of grinding mixing, ball milling mixing, magnetic stirring mixing, and vortex mixing.
6. The method for preparing a multi-carbon layer-supported metal atom material according to claim 2, characterized in that: The oxygen-free atmosphere in step 2 is one or a combination of helium, nitrogen, ammonia, hydrogen and argon.
7. The method for preparing a multi-carbon layer-supported metal atom material according to claim 2, characterized in that: The heat treatment temperature in step 2 is 600-1800°C, and the heating rate is 1-10°C·min -1 , constant temperature time is 0.5-10 h.
8. The multi-carbon layer-supported metal atom material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The tube wall thickness is no less than 0.6 nm, and metal atoms are dispersed in the multilayer carbon tubes.