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CN-121988275-A - Fe (Fe)2O3/Co3O4Preparation method and application of nanocomposite

CN121988275ACN 121988275 ACN121988275 ACN 121988275ACN-121988275-A

Abstract

The invention belongs to the technical field of materials, and particularly relates to a preparation method and application of a Fe 2 O 3 /Co 3 O 4 nano composite material. The invention synthesizes the bimetallic Fe/Co-MOF by adopting a one-step solvothermal method, and prepares the Fe 2 O 3 /Co 3 O 4 compound by MOF derivatization, which keeps the high specific surface area and the porosity of the precursor MOF. By MOF derivatization, the metal precursor can still maintain relatively uniform distribution in the decomposition process, and a uniformly distributed Fe 2 O 3 and Co 3 O 4 composite material is formed. The composite material has the advantages of low working temperature, short response recovery time, low detection limit and good selectivity. By high temperature annealing, fe 2 O 3 and Co 3 O 4 gradually crystallize and contact each other and react at the interface, forming a tightly contacting heterogeneous interface. At this interface, a heterojunction is formed by fermi level modulation and carrier transport. An internal electric field is formed in the Fe 2 O 3 /Co 3 O 4 compound, free electrons exist to migrate from Fe 2 O 3 to Co 3 O 4 , carrier mobility of the material surface is accelerated, and the Fe 2 O 3 /Co 3 O 4 gas sensor has low response and recovery time to acetone.

Inventors

  • YU BO
  • ZHAO YING
  • WANG RU
  • QI TAO
  • ZHANG YUANPING
  • Liu Lieni
  • Pu Xinhong
  • CHEN ZHICHENG
  • GE XIAODONG
  • LIU JUHUI
  • MAO SHENGHAO
  • WANG HAIJUN
  • ZHOU JIE
  • ZHOU XUEJUN
  • SONG ZIHAO
  • SUN XIAOLI
  • ZHANG GANGGANG
  • CHEN HAN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (9)

  1. 1. A preparation method of a Fe 2 O 3 /Co 3 O 4 nano composite material is characterized by comprising the following steps: Step 1) dissolving cobalt nitrate hexahydrate and ferric nitrate nonahydrate with the mass ratio of 10-20:1 in 25-40ml of N, N-dimethylformamide, and uniformly stirring to obtain cobalt-iron ion dispersion liquid; Step 2) dissolving dimethyl imidazole in 12-20ml of N, N-dimethylformamide, and uniformly stirring to obtain a ligand solution; wherein the mass of the dimethylimidazole is 50% of the total mass of the cobalt nitrate hexahydrate and the ferric nitrate nonahydrate; Step 3) adding the ferrocobalt ion dispersion liquid into the ligand solution while stirring, and continuously stirring for 30-60min to obtain a uniform solution; Step 4), pouring the uniform solution into a reaction kettle, and performing heating reaction at 180-210 ℃ for 24-36 h; And 5) after the reaction is finished, cooling to room temperature, sequentially carrying out centrifugal washing by using N, N-dimethylformamide and ethanol, and drying and annealing the washed product to obtain the Fe 2 O 3 /Co 3 O 4 nano composite material.
  2. 2. The method of claim 1, wherein the reaction vessel in the step 4) is a polytetrafluoroethylene-lined reaction vessel, and the reaction vessel is sealed during the reaction.
  3. 3. The method of claim 1, wherein the drying in step 5) is performed in an oven at 60-100deg.C to obtain a dried bimetallic Fe/Co-MOF material.
  4. 4. The method of claim 1, wherein the annealing in step 5) is performed at a high temperature of 500-650 ℃ for 4-6 hours.
  5. 5. An application of Fe 2 O 3 /Co 3 O 4 nanometer composite material in high-efficiency detection of volatile organic compounds.
  6. 6. The application of the Fe 2 O 3 /Co 3 O 4 nanocomposite in high-efficiency detection of volatile organic compounds according to claim 5, wherein the Fe 2 O 3 /Co 3 O 4 nanocomposite is coated on a planar electrode to obtain a gas sensor element of a gas sensor.
  7. 7. The use of the Fe 2 O 3 /Co 3 O 4 nanocomposite for efficient detection of volatile organic compounds according to claim 5, wherein: the volatile organic compound is acetone.
  8. 8. The application of the Fe 2 O 3 /Co 3 O 4 nanocomposite in high-efficiency detection of volatile organic compounds according to claim 6, wherein the thickness of the Fe 2 O 3 /Co 3 O 4 nanocomposite on the gas sensor is 0.25-0.30nm.
  9. 9. The method for efficiently detecting volatile organic compounds by using a Fe 2 O 3 /Co 3 O 4 nanocomposite as set forth in claim 6, wherein ethanol is added to form uniform slurry before coating the Fe 2 O 3 /Co 3 O 4 nanocomposite, the slurry is dipped with a brush pen after grinding, and the coating is repeated three times, each time after the coating is performed, the next coating is performed after the coating is performed naturally, and after the coating is performed, the gas sensor based on Fe 2 O 3 /Co 3 O 4 is obtained after the coating is performed in the shade at room temperature.

Description

Preparation method and application of Fe 2O3/Co3O4 nano composite material Technical Field The invention belongs to the technical field of materials, and particularly relates to a preparation method and application of a Fe 2O3/Co3O4 nano composite material. Background The semiconductor metal oxide gas sensor has good economy, simple operation, multifunction and wide detection range, and becomes an ideal choice for detecting VOCs. Semiconductor metal oxide gas sensors offer significant advantages over traditional monitoring methods, such as gas chromatography and mass spectrometry, in terms of portability, real-time monitoring, and cost effectiveness. However, conventional metal oxide-based gas sensors still have some inherent drawbacks, such as high operating temperature, poor selectivity, low long-term stability, etc., which limit their wide spread in practical applications. In order to solve these problems, researchers have recently adopted a series of improvement strategies to improve the performance of semiconductor metal oxide gas sensors. The foreign researchers Zhengfei Dai and （Dai Z, Lee CS, Kim B Y, et al. Honeycomb-like periodic porous LaFeO3 thin filmchemiresistors with enhanced gas-sensing performances.[J]. Acs AppliedMaterials&Interfaces, 2014, 6(18):16217-16226.） prepare the LaFeO 3 film by using the polystyrene nanospheres as templates, and the result shows that the honeycomb LaFeO 3 film has good acetone gas sensitivity, the minimum detection limit of the acetone is 50ppm, but the working temperature of the paper is higher and is about 400 ℃. In order to effectively reduce the operating temperature of the sensor and improve the selectivity of the sensor to specific VOCs, noble metal nanoparticles such as gold, silver, platinum and the like can be introduced. CN201611216957.5 is a high-selectivity acetone gas-sensitive material, a preparation method thereof and the application thereof disclose that the high-selectivity acetone gas-sensitive material is prepared from raw materials of Ag-LaFeO 3 gel, template molecules, functional monomers and an initiator, and is a lanthanum ferrite acetone gas-sensitive material with high sensitivity, good selectivity and low working temperature. However, noble metals are expensive, large-scale use greatly increases the production cost of materials, and silver may exhibit toxic effects in living beings and environments, and long-term exposure or accumulation may cause potential harm to the ecosystem and human health, which limits its wide application in the field of gas sensors. In addition, doping other metal ions or forming a composite material is a common modification method, so that the sensitivity and stability of the sensor can be remarkably improved. However, the doping or forming of composite materials requires precise control of the proportion, uniform distribution, and synthesis conditions of the doping elements, which increases the complexity and difficulty of the synthesis process, and the consistency of production is difficult to ensure. Thus, in a particular sensor manufacturing process, it is often necessary to go through fine material preparation, strict experimental condition control, and a series of performance tests. And (3) evaluating response characteristics of the sensor under different VOCs environments through a series of gas-sensitive test experiments, wherein the response characteristics comprise parameters such as sensitivity, selectivity, response time, recovery time and the like, and verifying the reliability and practicability of the sensor in actual environment monitoring. Disclosure of Invention The invention aims to provide a preparation method of a Fe 2O3/Co3O4 nano composite material, which adopts a one-step solvothermal method to synthesize bimetallic Fe/Co-MOF, and prepares a Fe 2O3/Co3O4 composite through MOF derivatization, so that the high specific surface area and the porosity of a precursor MOF are reserved. The invention further aims to provide an application of the Fe 2O3/Co3O4 nano composite material in efficient detection of volatile organic compounds. Therefore, the technical scheme provided by the invention is as follows: A method for preparing a Fe 2O3/Co3O4 nanocomposite, comprising the following steps: Step 1) dissolving cobalt nitrate hexahydrate and ferric nitrate nonahydrate with the mass ratio of 10-20:1 in 25-40ml of N, N-dimethylformamide, and uniformly stirring to obtain cobalt-iron ion dispersion liquid; Step 2) dissolving dimethyl imidazole in 12-20ml of N, N-dimethylformamide, and uniformly stirring to obtain a ligand solution; wherein the mass of the dimethylimidazole is 50% of the total mass of the cobalt nitrate hexahydrate and the ferric nitrate nonahydrate; Step 3) adding the ferrocobalt ion dispersion liquid into the ligand solution while stirring, and continuously stirring for 30-60min to obtain a uniform solution; Step 4), pouring the uniform solution into a reaction kettle, and performing