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CN-121972674-A - Magnetic CoCu/C micro-ring and preparation method and application thereof

CN121972674ACN 121972674 ACN121972674 ACN 121972674ACN-121972674-A

Abstract

The invention discloses a magnetic CoCu/C micro-ring and a preparation method and application thereof, comprising the following steps of (1) dissolving cobalt salt, copper salt and surfactant in water to prepare a metal ligand solution A, dispersing 2-methylimidazole in water to prepare an organic ligand solution B; mixing the solution A, B, stirring to react under heating to obtain a solid product, washing, freeze-drying to obtain a CoCu-ZIF micro-ring, and performing carbothermic reduction reaction under the condition of protective gas by taking the CoCu-ZIF micro-ring as a template and a precursor to obtain the magnetic CoCu/C micro-ring. The obtained CoCu/C micro-ring has excellent microwave absorption performance, and the maximum effective absorption bandwidth can reach 7.2GHz when the thickness is 1.8 mm in the range of 2-18 GHz. Meanwhile, the preparation method has the advantages of simple process, low energy consumption, capability of realizing mass preparation, wide application range and the like.

Inventors

  • HE NA
  • LIU ZHONGWU
  • ZHONG XICHUN
  • YU HONGYA
  • WU YAXIANG
  • MENG YUYING

Assignees

  • 华南理工大学

Dates

Publication Date
20260505
Application Date
20260122

Claims (10)

  1. 1. The preparation method of the magnetic CoCu/C micro-ring is characterized by comprising the following steps of: (1) Dissolving cobalt salt, copper salt and a surfactant in water to prepare a metal ligand solution A, dispersing 2-methylimidazole in the water to prepare an organic ligand solution B, mixing the solutions A, B, stirring and reacting under a heating condition to obtain a solid product, washing, and performing freeze drying treatment to obtain the CoCu-ZIF micro-ring; (2) And performing carbothermic reduction reaction under the condition of shielding gas by taking the CoCu-ZIF micro-ring as a template and a precursor to obtain the magnetic CoCu/C micro-ring.
  2. 2. The process according to claim 1, wherein the heating temperature in step (1) is 55-80 ℃ and the reaction time is 10-40 min.
  3. 3. The preparation method according to claim 2, wherein the solution A, B is heated to 65.+ -. 10 ℃ with stirring, and then the solution A is added to the solution B rapidly, and the reaction is carried out for 30.+ -. 10min with stirring under the heating condition.
  4. 4. The method according to claim 1,2 or 3, wherein the carbothermic reaction in step (2) is carried out at a temperature of 500 to 900 ℃ for a period of 1 to 3 hours.
  5. 5. The method according to claim 4, wherein the carbothermic reaction is carried out at a temperature of 700.+ -. 100 ℃ for a time of 2.+ -. 0.5 h.
  6. 6. The preparation method according to claim 1, 2 or 3, wherein the molar ratio of the cobalt salt to the copper salt in the step (1) is 0.1-10, the mass molar ratio of the surfactant to the cobalt salt is 0.1-5 g/mol, and the mass molar ratio of the 2-methylimidazole to the cobalt salt is 0.1-5 g/mol.
  7. 7. The preparation method of claim 6, wherein the molar ratio of the cobalt salt to the copper salt in the step (1) is 0.5-2, the mass molar ratio of the surfactant to the cobalt salt is 0.5-2 g/mol, and the mass molar ratio of the 2-methylimidazole to the cobalt salt is 0.05-2 g/mol.
  8. 8. The preparation method of the carbon thermal reduction catalyst according to claim 1, 2 or 3, wherein the surfactant in the step (1) is cetyl trimethyl ammonium bromide, the cobalt salt is one or more of cobalt chloride and cobalt nitrate, the copper salt is one or more of copper chloride and copper nitrate, the flow rate of the protective gas in the step (2) is 20-50 mL/min, and the heating rate of the carbon thermal reduction reaction is 1-10 ℃.
  9. 9. A magnetic CoCu/C micro-ring made by the method of any one of claims 1-8.
  10. 10. The use of the magnetic CoCu/C micro-ring of claim 9 in fuel cells, adsorptive separation, microwave absorbing articles, sensing, biomedical, electronic and optical applications.

Description

Magnetic CoCu/C micro-ring and preparation method and application thereof Technical Field The invention relates to the technical field of organic Metal framework (Metal-Organic Framework, MOF) nano-composite, in particular to a simple preparation method and application of a magnetic CoCu/C micro-ring, belonging to the field of microwave absorbing materials (Microwave absorbing materials, MAM). Background With the rapid development of 5G communication, intelligent equipment and electronic information technology, electromagnetic wave absorbing materials are increasingly widely applied in the civil field. A popular model for high performance MAM is to combine dielectric and magnetic components together so that the composite material produced can benefit from complementary loss mechanisms and significant synergistic effects. In order to meet the light weight requirements in the fields of aerospace, wearable devices and the like, the combination of magnetic metal and carbon materials has been considered as one of the most effective methods for achieving "thin, light, wide and strong" technical indexes. On the one hand, magnetic metal particles can provide magnetic losses, and on the other hand, the carbon matrix has adjustable dielectric properties and a programmable microstructure. The focus in the preparation of magnetic metal/carbon composites is to optimize the chemical composition and microstructure, which will enhance their microwave absorption properties. The method is characterized in that the microstructure of the wave-absorbing material is regulated and controlled, and the core aim is to optimize the loss mechanism of the wave-absorbing material, namely, the interface polarization loss is enhanced by constructing rich heterogeneous interfaces, the shape anisotropy field is provided for the magnetic component by means of specific morphology, so that the high-frequency magnetic permeability is improved, and meanwhile, a long-range conductive network is established to promote the conductivity loss. Therefore, the design and preparation of the carbon-magnetic composite material with controllable morphology have important significance for the definition and cooperation of each loss mechanism. The central hole of the magnetic nano ring is the key point of realizing a unique and stable magnetization configuration, thereby fundamentally avoiding the formation of vortex nuclei and eliminating the problem of exchange energy density divergence at the position. In addition, the aspect ratio and radial perpendicular anisotropy strength of the nanoring can control the stable magnetic configuration as well as the location and number of frequency peaks in the ferromagnetic resonance. Therefore, the magnetic nano-ring is an ideal candidate material for designing a novel efficient microwave absorber. At present, the synthesis of the magnetic micro/nano ring mainly utilizes the physical and chemical properties of the material, such as amphiphilic interface, atomic diffusion, magnetic dipole interaction and the like, to drive the formation of a ring structure. The chemical method has advantages in the aspects of purity control and morphology regulation, but generally faces the problems of complex process, limited universality, difficult scale and the like. For example, a microwave-assisted sugar reduction-etching method is adopted in the patent document (CN 104671292B) to prepare a Fe 3O4 polycrystalline nanoring with controllable size, an alpha-Fe 2O3 nanoring is firstly synthesized by a hydrothermal method in the patent document (CN 115532244B) and then reduced to obtain a gamma-Fe 2O3 magnetic nanoring, and a layer-by-layer self-assembly is combined by the hydrothermal method in the patent document (CN 108578695B) to prepare the nickel-cobalt alloy nanoring with the surface functionalized. These cases show that the existing chemical synthesis route can realize the controllable preparation of the annular structure of the specific material, but the technology is still challenging in terms of process simplification and mass production. The invention adopts a liquid phase method to construct an annular metal organic framework precursor, and then carries out high-temperature annealing treatment to obtain the CoCu/C micro-ring with the characteristics of annular structure and adjustable components. The method can realize controllable preparation of the precursor size and morphology, and has the advantages of short preparation period, low cost, easy scale and the like. The obtained CoCu/C micro-ring has excellent corrosion resistance and structural stability, and has wide application prospect in the fields of electrode materials, electrocatalysis, microwave absorption and shielding, photoelectric conversion and the like. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a preparation method of a precursor of a CoCu-ZIF micro-ring and a CoCu/C micro-ring. The invention solves the