Search

CN-122006778-A - Fe-Mn double-monoatomic catalyst, preparation method and application thereof

CN122006778ACN 122006778 ACN122006778 ACN 122006778ACN-122006778-A

Abstract

The invention discloses a Fe-Mn double single-atom catalyst, a preparation method and application thereof, and belongs to the technical fields of environmental catalytic materials and water treatment advanced oxidation. The catalyst takes N-doped porous carbon derived from tussah cocoons as a carrier, and takes atomically dispersed Fe and Mn as active components to form a symmetrical N 4 –Mn–Fe–N 4 coordination structure, wherein Fe and Mn are respectively coordinated with 4N atoms, and strong electronic interaction exists between the Fe and Mn to bond with heteronucleuses. The biomass tussah cocoons are used as a carbon-nitrogen source, and the catalyst is prepared through four steps of degumming, metal ion adsorption, high-temperature pyrolysis and acid washing purification, so that the raw materials are cheap and easy to obtain, the process is simple and controllable, and the large-scale production can be realized. The catalyst can efficiently activate peroxyacetic acid, build sustainable Fe 3+ /Fe 2+ and Mn 4+ /Mn 3+ to cooperate with redox circulation, selectively generate hydroxyl free radicals and singlet oxygen, and efficiently degrade organic pollutants such as sulfonamide antibiotics, phenols and the like. The invention discloses a catalytic mechanism through combination of DFT theoretical calculation and multidimensional characterization, and proves that the catalyst has excellent catalytic activity, anti-interference performance and cycling stability in a wide pH range and a complex water matrix, and has wide application prospect in the field of deep purification of industrial wastewater and drinking water.

Inventors

  • ZHENG HENG
  • WANG YANGYANG
  • XU JIANING

Assignees

  • 广西科技大学

Dates

Publication Date
20260512
Application Date
20260326

Claims (10)

  1. 1. The Fe-Mn diatomic catalyst is characterized in that N-doped porous carbon is used as a carrier, atomically dispersed Fe and Mn are used as active components, and the Fe and Mn form a symmetrical N 4 –Mn–Fe–N 4 coordination structure on the N-doped porous carbon carrier, wherein Fe atoms coordinate with 4N atoms, mn atoms coordinate with 4N atoms, heteronuclear metal bonding effect exists between Fe and Mn, and Fe-Mn diatomic pairs are formed.
  2. 2. The Fe-Mn diatomic catalyst according to claim 1, wherein the mass loading of Fe in the catalyst is 2.0-3.0 wt%, the mass loading of Mn is 1.5-2.0 wt%, and the atomic distance of the Fe-Mn diatomic pairs is 0.20-0.25 nm.
  3. 3. The Fe-Mn diatomic catalyst of claim 1, wherein the N-doped porous carbon is a tussah cocoon derived carbon material having a fibrous morphology and a hierarchical micro-mesoporous structure, a specific surface area of 150-250 m 2 /g, and a pore volume of 0.15-0.20 cm 3 /g.
  4. 4. The Fe-Mn diatomic catalyst according to claim 1, wherein the N element in the catalyst is present as pyridine nitrogen, metal-N coordination bonds, graphite nitrogen and nitrogen oxide, wherein the ratio of metal-N coordination bonds is equal to or greater than 24% and the ratio of graphite nitrogen is equal to or greater than 38%.
  5. 5. The Fe-Mn diatomic catalyst according to claim 1, wherein Fe exists in the mixed valence state of Fe 2+ and Fe 3+ , mn exists in the mixed valence state of Mn 3+ and Mn 4+ , the 2p orbital binding energy of Fe in the catalyst is more than or equal to 0.1 eV compared with that of single atom Fe/N-C, the Fe 2+ ratio is more than or equal to 8%, and the 2p orbital binding energy of Mn in the catalyst is more than or equal to 0.2 eV compared with that of single atom Mn/N-C.
  6. 6. A method for preparing the Fe-Mn diatomic catalyst according to any one of claims 1 to 5, comprising the following steps: S1, silk degumming treatment, namely putting tussah cocoons into a sodium carbonate aqueous solution, heating, boiling and degumming, washing to neutrality after the reaction is completed, and drying to obtain degummed silk fibers; S2, adsorbing a metal precursor, namely immersing degummed silk fibers into a mixed aqueous solution containing ferric salt and manganese salt, standing at room temperature, adsorbing and drying to obtain a metal-loaded silk precursor; S3, high-temperature pyrolysis, namely placing the metal-loaded silk precursor in an inert atmosphere, heating to 800-1000 ℃ through programming, carrying out thermal insulation pyrolysis, and naturally cooling to obtain a pyrolysis product; S4, acid washing and purifying, namely acid washing the pyrolysis product by dilute nitric acid, washing to be neutral, centrifuging, and vacuum drying to obtain the Fe-Mn double single-atom catalyst.
  7. 7. The method according to claim 6, wherein in the step S1, the concentration of the sodium carbonate aqueous solution is 0.1-0.3M, the boiling temperature is 90-100 ℃, and the heat preservation time is 2-4 hours.
  8. 8. The preparation method of claim 6, wherein in the step S3, the inert atmosphere is argon or nitrogen, the temperature-programmed heating rate is 2-5 ℃ per minute, and the pyrolysis heat-preserving time is 4-8 hours.
  9. 9. The use of the Fe-Mn double monoatomic catalyst according to any one of claims 1 to 5, wherein the Fe-Mn double monoatomic catalyst is used for activating peracetic acid in a Fenton-like water purification system to degrade organic pollutants in water.
  10. 10. The application of the catalyst according to claim 9, wherein the adding amount of the catalyst in the water body is 0.05-0.2 g/L, the adding concentration of the peracetic acid in the water body is 0.1-1.0 mM, the pH value of the water body is 3.0-11.0, and the organic pollutant comprises at least one of sulfonamide antibiotics, phenolic organic matters and dye organic matters.

Description

Fe-Mn double-monoatomic catalyst, preparation method and application thereof Technical Field The invention belongs to the technical field of environmental catalytic materials and advanced oxidation of water treatment, and particularly relates to an Fe-Mn double-monoatomic catalyst, a preparation method and application thereof. Background With the acceleration of industrialization and urbanization, the discharge of persistent organic pollutants (especially antibiotics, phenolic endocrine disruptors and the like) in water bodies poses serious threats to the ecological environment and human health. Advanced Oxidation Processes (AOPs) realize efficient degradation and mineralization of organic pollutants by generating high Reactive Oxygen Species (ROS), and are one of the most promising technologies in the current water treatment field. The monoatomic catalyst (SACs) has the advantages of maximized atomic utilization rate, definite coordination environment of active sites, high catalytic selectivity and the like, and is widely researched in Fenton-like advanced oxidation systems. However, the existing single-atom catalyst still has a plurality of bottlenecks that the synthesis process is complex and difficult to prepare in a large scale, isolated metal active sites lead to slow redox kinetics, low interfacial charge transfer efficiency, narrow pH application range, easiness in being interfered by co-existing ions and organic matters in a water body, easiness in deactivation of the active sites, poor circulation stability and difficulty in maintaining long-term and efficient ROS generation, and meanwhile, the single-atom sites are difficult to realize accurate regulation and control on various ROS generation paths, and cannot be matched with the synergistic degradation of various organic pollutants in a complex water body. The double-atom catalyst can optimize the electronic structure of the active site by means of the electronic synergistic effect of adjacent metal sites by coupling two metal centers in an atomic scale, promote charge delocalization, construct double-metal redox circulation, and greatly improve the catalytic activity and stability. Wherein, fe and Mn have complementary oxidation-reduction potential, and the coupling of the two can realize the efficient regeneration of Fe 3+/Fe2+ and Mn 4+/Mn3+ circulation, thus being an ideal active component of Fenton-like catalytic system. However, the design and preparation of the Fe-Mn diatomic catalyst still have key defects that 1) the coordination structure of an active site is not clear, the accurate regulation and control of an electronic structure cannot be realized, the molecular mechanism of a bimetal synergistic effect is not clear, the selective regulation and control of ROS generation is difficult to realize, 2) the preparation process is complex, the large-scale production cannot be realized by relying on an expensive carbon source and complex synthesis equipment, and 3) the anti-interference capability, the circulation stability and the engineering applicability of the catalyst in an actual water body still cannot meet the requirements of actual water treatment. Therefore, the Fe-Mn diatomic catalyst which has definite coordination structure, high catalytic activity, good stability and simple preparation process and can be scaled is developed, and the mechanism of peroxyacetic acid activation and pollutant degradation is clear, so that the Fe-Mn diatomic catalyst has important significance for promoting the application of Fenton-like advanced oxidation technology in actual water treatment. Disclosure of Invention Aiming at the defects and shortcomings in the prior art, the primary purpose of the invention is to provide an Fe-Mn double-single-atom catalyst which has a definite N 4–Mn–Fe–N4 symmetrical coordination structure, an electronic structure can be accurately regulated and controlled, the catalytic activity is high, the stability is good, the pH application range is wide, and the anti-interference capability is strong. The second object of the invention is to provide a preparation method of the Fe-Mn double single-atom catalyst, which takes cheap biomass as a raw material, has simple and controllable process, does not need complex equipment, and can realize large-scale preparation. The third object of the invention is to provide an application of the Fe-Mn double-single-atom catalyst in Fenton-like water purification, wherein the catalyst can efficiently activate peracetic acid, realize broad-spectrum, efficient and stable degradation on various organic pollutants in a water body, and adapt to the actual water treatment requirements of a complex water body. In order to achieve the aim, the invention provides an Fe-Mn diatomic catalyst, which takes N-doped porous carbon as a carrier and takes Fe and Mn which are dispersed in atomic scale as active components, wherein the Fe and Mn form a symmetrical N 4–Mn–Fe–N4 coordination structure on t