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CN-117943053-B - Micro-flower manganese cobaltate composite catalyst and preparation method and application thereof

CN117943053BCN 117943053 BCN117943053 BCN 117943053BCN-117943053-B

Abstract

The micro-flower manganese cobaltate composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 has a micro-flower shape, wherein spinel structure transition metal oxide MnCo 2 O 4 has a petal shape with a thickness of 10 nm-15 nm, the petals are uniformly distributed, the diameter of the micro-flower is 1.5 mu m-2 mu m, the micro-flower shape has rich gaps, a larger specific surface area provides more contact sites, delta-MnO 2 is formed by gathering flaky microsphere structure particles on the surface of MnCo 2 O 4 micro-flower, the diameter of the flaky microsphere structure particles is 90 nm-120 nm, pt nano particles are uniformly loaded on the surface of MnCo 2 O 4 micro-flower, the diameter of the Pt nano particles is 1 nm-2 nm, the surface of the micro-flower manganese cobaltate composite catalyst is rough, and a heterojunction is formed between delta-MnO 2 and MnCo 2 O 4 . The preparation method of the micro-flower manganese cobaltate composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 is simple and convenient, firstly, a MnCo 2 O 4 carrier with micro-flower morphology is synthesized through a solvothermal method and a heat treatment, and then the micro-flower composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 is prepared by loading delta-MnO 2 and Pt nano particles on the carrier through a deposition-precipitation method and an in-situ reduction method. The prepared micro-flower manganese cobaltate composite catalyst has high stability and catalytic activity, and can be used for remarkably catalyzing, oxidizing and degrading formaldehyde and benzene series such as toluene at room temperature.

Inventors

  • LIU WEI
  • Fan Bangqiu
  • NING YANG
  • Ji Yajia
  • YU XINYING
  • ZHAO JING
  • Cui Haokang

Assignees

  • 天津工业大学

Dates

Publication Date
20260505
Application Date
20240108

Claims (10)

  1. 1. A microflora manganese cobaltate composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 is characterized in that: the spinel-structure transition metal oxide MnCo 2 O 4 is formed by closely stacking oxygen ions according to cubes, mn 2+ is filled in eighth tetrahedral gaps, co 3+ is filled in half of octahedral gaps, pt@ delta-MnO 2 @MnCo 2 O 4 has a micro-flower shape, petal thickness is 10-15 nm, distribution is uniform, micro-flower diameter is 1.5-2 mu m, a MnCo 2 O 4 carrier has the micro-flower shape and has rich gaps, a larger specific surface area provides more contact sites, delta-MnO 2 particles and Pt nano particles are uniformly loaded on the micro-flower surface, wherein delta-MnO 2 is a flaky microsphere structure particle which is aggregated on the MnCo 2 O 4 micro-flower surface, the diameter is 90-120 nm, pt nano particles are fine particles which are uniformly loaded on the MnCo 2 O 4 micro-flower surface, the diameter is 1-2 nm, the micro-flower manganese cobaltate composite catalyst has a rough surface, and a heterojunction is formed between delta-MnO 2 and Mn 2 O 4 .
  2. 2. A method for preparing the micro-flower-shaped composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 according to claim 1, wherein the micro-flower-shaped composite catalyst is formed by compounding micro-flower-shaped MnCo 2 O 4 stably loaded delta-MnO 2 particles and Pt nano particles, and the specific preparation method comprises the following steps: Step one, preparing a MnCo 2 O 4 carrier: Mn (CH 3 COO) 2 ·4H 2 O and Co (CH 3 COO) 2 ·4H 2 O are used as Mn and Co sources, PVP is used as a surface protective agent), a MnCo 2 O 4 nano-sheet precursor is prepared by a solvothermal method, then the obtained precursor solution is transferred to a stainless steel high-pressure reaction kettle for heat treatment reaction, and finally the obtained precursor solution is naturally cooled to room temperature to prepare MnCo 2 O 4 micro-flowers; Step two, preparing delta-MnO 2 @MnCo 2 O 4 : Taking KMnO 4 and MnSO 4 ·H 2 O as Mn sources, loading delta-MnO 2 on MnCo 2 O 4 micro flowers by a deposition-precipitation method, forming a heterojunction between delta-MnO 2 and MnCo 2 O 4 , and obtaining delta-MnO 2 @MnCo 2 O 4 after centrifugation, washing and vacuum drying; Preparation of Pt@ delta-MnO 2 @MnCo 2 O 4 : And (3) taking H 2 PtCl 6 ·6H 2 O as a Pt source and NaBH 4 as a reducing agent, and synthesizing Pt nano particles on the surface of delta-MnO 2 @MnCo 2 O 4 in situ to prepare the Pt@ delta-MnO 2 @MnCo 2 O 4 micro-flower-shaped composite catalyst.
  3. 3. The preparation method according to claim 2, characterized in that: in the first step, the temperature in the stainless steel high-pressure reaction kettle is constant at 180 ℃ for 12 hours.
  4. 4. The preparation method according to claim 2, characterized in that: In the second step, the mass ratio of MnCo 2 O 4 to KMnO 4 to MnSO 4 ·H 2 O is controlled to be 2.0:1-10.0:1, and the mass ratio of MnCo 2 O 4 to delta-MnO 2 is controlled to be 2.7:1-13.6:1.
  5. 5. The preparation method according to claim 2, characterized in that: In the second step, the deposition-precipitation method is to heat and stir for 3 hours in a water bath at 60 ℃.
  6. 6. The preparation method according to claim 2, characterized in that: In the third step, the concentration range of H 2 PtCl 6 ·6H 2 O is 0.09-0.10M, and the mass fraction of the loaded Pt in Pt@ delta-MnO 2 @MnCo 2 O 4 is controlled to be 0.1-1 wt%.
  7. 7. The use of the micro-flower-like composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 according to claim 1, which is characterized in that the micro-flower-like composite catalyst is used for catalyzing and oxidizing formaldehyde at room temperature, and can remarkably reduce formaldehyde concentration.
  8. 8. Use of the micro-flower-like composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 according to claim 1 for the catalytic degradation of substances other than formaldehyde.
  9. 9. The use of the micro-flower-like composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 according to claim 8, the catalytic degradation of substances other than formaldehyde into a catalytic degradation of benzene series.
  10. 10. The use of the micro-flower shaped composite catalyst Pt@ delta-MnO 2 @MnCo 2 O 4 according to claim 9, the catalytic degradation of benzene series is the catalytic degradation of toluene.

Description

Micro-flower manganese cobaltate composite catalyst and preparation method and application thereof Technical Field The invention relates to the field of composite catalysts, in particular to a micro-flower manganese cobaltate composite catalyst Pt@ delta-MnO 2@MnCo2O4, a preparation method thereof and application thereof in catalytic degradation of organic pollutants. Background Indoor air pollution poses a major threat to human health, with formaldehyde and benzene-based species in VOCs, such as toluene, being two major hazardous substances. For the remediation of these contaminants, catalyst degradation techniques are considered to be both effective and environmentally friendly methods. Currently, various catalysts have been developed, such as supported transition metal oxide (MnO 2、Co3O4、CeO2, etc.) and supported noble metal (e.g., au, pt, pd, etc.) catalysts, and transition metal oxide catalysts such as MnO 2 generally require relatively high temperatures (> 150 ℃) to achieve a good catalytic effect on formaldehyde and benzene systems, thereby completely removing contaminants, and noble metal catalysts tend to exhibit good catalytic effects at relatively low temperatures, even at room temperature, which is not enough for the cost of noble metal catalysts to be higher. In view of the above problems, a need exists for a composite catalyst that can efficiently catalyze, oxidize and degrade formaldehyde and benzene series at room temperature. Spinel type ferrite is widely used as a catalyst carrier, wherein n type semiconductor MnCo 2O4 has the advantages of narrow band gap, high catalytic activity, good chemical stability, environmental friendliness and the like. These unique advantages make it a good candidate for catalyzing the degradation of contaminants. The catalyst can be effectively combined with the transition metal oxide particles and the noble metal nano particles, and the catalytic degradation effect is improved by generating structures such as atomic vacancies, occupation and the like. Therefore, the patent discloses a stable and simple composite catalyst material with the micro-flower MnCo 2O4 as an active carrier and a preparation method thereof, so as to solve the problem of high-efficiency catalytic degradation of formaldehyde and benzene series at room temperature. Disclosure of Invention In view of the above, the invention aims to solve the technical problems that the existing composite catalyst has complex preparation process, poor catalytic degradation performance on pollutants, higher raw material cost and the like. Aiming at the technical problems, the invention provides a micro-flower-shaped composite catalyst material and a preparation method thereof, which can obviously catalyze and oxidize formaldehyde and benzene series at room temperature and reduce the concentration of the formaldehyde and the benzene series. The invention provides the following technical scheme: The micro-flower manganese cobaltate composite catalyst Pt@ delta-MnO 2@MnCo2O4 is formed by closely stacking oxygen ions according to cubes, mn 2+ is filled in one eighth tetrahedral gaps, co 3+ is filled in one half of octahedral gaps, pt@ delta-MnO 2@MnCo2O4 has micro-flower morphology, petal thickness is 10 nm-15 nm, distribution is uniform, micro-flower diameter is 1.5-2 mu m, mnCo 2O4 carrier has micro-flower morphology and rich gaps, larger specific surface area provides more contact sites, delta-MnO 2 particles and Pt nano particles are uniformly loaded on the micro-flower surface, wherein delta-MnO 2 is a flaky microsphere structure particle, the diameter is 90 nm-120 nm, pt nano particles are uniformly loaded on the MnCo 2O4 micro-flower surface, the diameter is 1 nm-2 nm, and the micro-flower manganese cobaltate composite catalyst has rough surface and simultaneously forms a hetero-junction between delta- 2 and MnO 38. The micro-flower-shaped manganese cobaltate composite catalyst Pt@ delta-MnO 2@MnCo2O4 is prepared by a solvothermal method and heat treatment, and has high catalytic activity and high stability. The preparation method of the micro-flower-shaped composite catalyst Pt@ delta-MnO 2@MnCo2O4 is characterized in that the micro-flower-shaped composite catalyst is formed by compounding micro-flower-shaped MnCo 2O4 stably loaded delta-MnO 2 particles and Pt nano particles, and the specific preparation method comprises the following steps: Step one, preparing a MnCo 2O4 carrier: Mn (CH 3COO)2·4H2 O and Co (CH 3COO)2·4H2 O are used as Mn and Co sources, PVP is used as a surface protective agent), a MnCo 2O4 nano-sheet precursor is prepared by a solvothermal method, then the obtained precursor solution is transferred to a stainless steel high-pressure reaction kettle for heat treatment reaction, and finally the obtained precursor solution is naturally cooled to room temperature to prepare MnCo 2O4 micro-flowers; Step two, pt@ delta-MnO 2@MnCo2O4 preparation: Taking KMnO 4 and MnSO 4·H2 O as Mn sources, l