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CN-122006821-A - H-Co with hollow core-shell tubular structure3O4@CoMn-LDH catalyst and preparation method and application thereof

CN122006821ACN 122006821 ACN122006821 ACN 122006821ACN-122006821-A

Abstract

The invention relates to the technical field of preparation of novel efficient catalysts and pollutant degradation, in particular to a hollow core-shell tubular structure h-Co 3 O 4 @CoMn-LDH catalyst and a preparation method and application thereof. The composite catalyst comprises a hollow h-Co 3 O 4 pipe and a CoMn-LDH ultrathin nano sheet formed on the surface of the hollow pipe through in-situ growth, so that the double-metal-based hollow core-shell structure composite catalyst with high specific surface area and high dispersion active sites is formed, and active oxygen species generated by persulfate can be activated more efficiently and stably to degrade organic pollutants.

Inventors

  • YANG WENNING
  • WANG DONG
  • HE QINGPENG
  • YANG HUA
  • DU FANGHUI
  • LI HONGGANG

Assignees

  • 聊城大学

Dates

Publication Date
20260512
Application Date
20260318

Claims (10)

  1. 1. The hollow core-shell tubular structure h-Co 3 O 4 @CoMn-LDH composite catalyst is characterized by comprising a hollow h-Co 3 O 4 tube and CoMn-LDH ultrathin nano sheets formed on the surface of the hollow h-Co 3 O 4 tube through in-situ growth, so as to form the composite catalyst with a core-shell structure.
  2. 2. The h-Co 3 O 4 @CoMn-LDH composite catalyst according to claim 1, wherein the hollow h-Co 3 O 4 tube is obtained by impregnating natural bay fiber seed hairs including at least one of goose down vine seed hairs, ox horn seed hairs, wood cotton seed hairs, dandelion seed hairs, cattail seed hairs, sycamore seed hairs, cattail seeds or poplar seeds with cobalt salt and calcining.
  3. 3. A method for preparing the h-Co 3 O 4 @ CoMn-LDH composite catalyst according to claim 1 or 2, comprising the steps of: (1) The preparation of the hollow h-Co 3 O 4 pipe comprises the steps of immersing natural flossing fiber seed wool in cobalt salt ethanol solution, filtering, drying, and calcining at 500-600 ℃ for 1-2 h to obtain a hollow h-Co 3 O 4 pipe; (2) And (3) preparing the hollow core-shell structure h-Co 3 O 4 @CoMn-LDH, namely dispersing the hollow h-Co 3 O 4 pipe obtained in the step (1) in a precursor solution containing a manganese source and an alkali source, performing hydrothermal reaction, and separating, washing and drying after the reaction is finished to obtain the h-Co 3 O 4 @CoMn-LDH composite catalyst.
  4. 4. The method according to claim 3, wherein in the step (1), the concentration of the cobalt salt ethanol solution is 0.05-0.2 mol/L, the amount of the natural flossing fiber seed wool is 0.2-0.8 g, and the soaking time is 8-12 h.
  5. 5. The method according to claim 3, wherein in the step (1), the cobalt salt is any one of cobalt nitrate, cobalt chloride, cobalt acetate, cobalt acetylacetonate and cobalt sulfate.
  6. 6. The preparation method of claim 3, wherein in the step (2), the dosage ratio of the hollow h-Co 3 O 4 pipe, the manganese source and the alkali source is 100-300 mg, 0.5-2 mmol and 2-6 mmol, the manganese source is any one of manganese nitrate, manganese acetate, manganese chloride, manganese acetylacetonate or manganese sulfate, and the alkali source is any one of urea or urotropine.
  7. 7. The preparation method according to claim 3, wherein in the step (2), the hydrothermal reaction is performed at a temperature of 80-140 ℃ for 8-12 hours, the washing is performed by sequentially washing with water and ethanol, the drying temperature is 50-80 ℃, and the drying time is 2-5 hours.
  8. 8. A method of preparation according to claim 3 wherein in step (2) the hollow h-Co 3 O 4 tube is partially dissolved during the reaction to provide the cobalt source required to form the CoMn-LDH without the need for additional addition of cobalt salts.
  9. 9. Use of the h-Co 3 O 4 @ CoMn-LDH composite catalyst according to claim 1 or 2, or the h-Co 3 O 4 @ CoMn-LDH composite catalyst prepared by the preparation method according to any one of claims 3-8, in activating persulfate to degrade organic pollutants.
  10. 10. The use according to claim 9, wherein the persulfate is a peroxymonosulfate or a peroxydisulfate, and the organic contaminant comprises any one of an antibiotic, a dye or a drug, preferably chloroquine phosphate.

Description

Hollow core-shell tubular structure h-Co 3O4 @CoMn-LDH catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of preparation of novel efficient catalysts and pollutant degradation, in particular to a hollow core-shell tubular structure h-Co 3O4 @CoMn-LDH catalyst and a preparation method and application thereof. Background The disclosure of this background section is only intended to increase some understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. Chloroquine phosphate (CQP) is an antimalarial drug that is widely used in the treatment of amoeba, connective tissue disease and novel coronaviruses. The organic pollutants have the characteristics of low concentration, large potential hazard, stable structure, strong accumulation and the like in the water environment, and the organic pollutants are difficult to quickly and thoroughly remove by the traditional water treatment technology. Advanced oxidation techniques based on persulfates (including peroxomonosulfates and peroxodisulfates) have been demonstrated to degrade such contaminants into less toxic small molecule substances and even mineralize into carbon dioxide. However, the biggest disadvantage of persulfate is that it is difficult to oxidize organic contaminants directly, and it is required to function by heating, ultraviolet irradiation or catalyst activation. At present, cobalt-based catalysts are considered as the most effective persulfate activators, but the existing cobalt-based catalysts still face the problems of insufficient exposure of active sites, low charge transmission efficiency, poor structural stability and the like, and particularly have great challenges in the aspects of three-dimensional structural design and large-scale preparation of the catalysts. Disclosure of Invention Aiming at the problems, the invention builds the composite material with the multi-component and layered structure, fully utilizes the combined action of the multi-component and the space structure, and simultaneously improves the catalytic activity and the structural stability of the catalytic material. First is the screening of the multicomponent components, the active core of which is known to be the cleavage of its O-O bonds (bond energy about 140 kJ/mol) by electron transfer processes, yielding reactive oxygen species (ROS, such as OH, SO 4-·、1O2, etc.) to degrade organic pollutants. The invention selects cobalt (Co) as a main active center, the common valence state of Co element is Co 2+/Co3+, and the standard oxidation-reduction potential (E 0(Co3+/Co2+) =1.81V) of the Co element is highly matched with the electron transfer energy level required by persulfate O-O bond fracture. Theoretically, co 2+ can directly reduce persulfate (such as PMS: HSO 5-+ Co2+→ SO4-· + Co3++ OH-) through single electron transfer, and Co 3+ can be regenerated into Co 2+ through reaction with pollutant molecules or reducing agents (such as H 2 O and organic substrates) in a system, so that stable Co 2+/Co3+ circulation is formed, and persulfate activation is continuously driven. Compared to other transition metals (e.g., E 0 =1.59V of E 0=0.77 V,Ni3+/Ni2+ of Fe 3+/Fe2+), the redox potential of Co more readily enables efficient activation of persulfate and the kinetic rate of Co 2+/Co3+ cycle is faster, a highly efficient active component of persulfate activation. Further, based on the three-dimensional theoretical requirement of 'main active center synergy + reaction mechanism complementation + structural stability enhancement', the invention selects manganese (Mn) and Co to form a bimetal composite system to improve the catalytic performance of the catalyst. Mn has a rich valence state (Mn 2+、Mn3+、Mn4+, etc.), and its redox potential interval (e.g., E 0(Mn3+/Mn2+)=1.54 V,E0(MnO2/Mn3+) =0.95V) overlaps with the Co 2+/Co3+ cycle with energy levels. In theory, mn can be used as an electronic bridge to participate in valence state circulation of Co, on one hand, mn 2+ can reduce Co 3+ into Co 2+（Co3++ Mn2+→ Co2++ Mn3+ to accelerate regeneration of Co main active centers and solve the problem of slower reduction rate of Co 3+ in a single Co system, on the other hand, generated Mn 3+/Mn4+ can further activate persulfate (such as Mn 3++ HSO5-→ SO4-· + MnO2++ OH-) to form a bimetallic cycle of Co activation-Mn regeneration-Mn auxiliary activation, and the electron transfer efficiency and the persulfate activation rate are greatly improved. in addition, the composite enhancement of Mn and Co can strengthen the stability of the core-shell structure, wherein Mn grows on the surface of the h-Co 3O4 core in situ in the form of CoMn-LDH nano-sheets. In theory, co 2+ and Mn 2+ have similar ionic radii (Co 2+ radius 0.074 nm and Mn 2+ radius 0.080 nm