Search

CN-119581581-B - Fe-S-N-C cathode oxygen reduction catalyst doped with iron by sulfur, preparation method and application

CN119581581BCN 119581581 BCN119581581 BCN 119581581BCN-119581581-B

Abstract

The invention provides a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts and preparation thereof. The preparation method comprises the steps of mixing and pyrolyzing ZIF-8 with a regular dodecahedron framework structure and a nitrogen-containing ligand to form a nitrogen-coated nitrogen-carbon substrate, wherein the nitrogen-carbon substrate has a regular dodecahedron framework structure, and carrying out chemical vapor deposition on a precursor ferric salt, a precursor sulfur salt and the nitrogen-coated nitrogen-carbon substrate to obtain the Fe-S-N-C cathode oxygen reduction catalyst of sulfur-doped iron. The invention reduces electrons around the active center of Fe, improves interaction with oxides, promotes oxygen reduction process of four-electron transfer in subsequent application, reduces dissolution of Fe, and improves the cycling stability of the catalyst.

Inventors

  • GE JUNJIE
  • LIN LIN

Assignees

  • 中国科学技术大学

Dates

Publication Date
20260512
Application Date
20241216

Claims (7)

  1. 1. A preparation method of a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst comprises the following steps: Mixing and pyrolyzing ZIF-8 with a regular dodecahedron framework structure and a nitrogen-containing ligand to form a nitrogen-coated nitrogen-carbon substrate, wherein the nitrogen-carbon substrate has the regular dodecahedron framework structure; Performing chemical vapor deposition on a precursor iron source, a precursor sulfur source and the nitrogen-coated nitrogen-carbon substrate to obtain a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst, breaking the symmetrical structure of Fe-N 4 sites through sulfur doping, and changing the spin and charge density of an active center of Fe-N 4 , wherein the chemical vapor deposition temperature is 750-900 ℃ and the time is 2-4 hours; The precursor iron source and the precursor sulfur source are subjected to common vapor deposition to form uniform distribution of iron and sulfur, wherein the precursor iron source is ferrocene, the precursor sulfur source is thiourea, and the molar ratio of the precursor iron source to the precursor sulfur source to the nitrogen-coated nitrogen-carbon substrate is 1:1 (1.6-3.2); The mixing pyrolysis of ZIF-8 with a framework structure of regular dodecahedron and a nitrogen-containing ligand to form a nitrogen-coated nitrogen-carbon substrate comprises: Dissolving ZIF-8 and the nitrogen-containing ligand in a solvent, and mixing to obtain a suspension; sequentially carrying out rotary steaming, drying and grinding on the suspension to obtain a nitrogen-coated ZIF-8; Pyrolyzing the nitrogen-coated ZIF-8 in a protective atmosphere to obtain the nitrogen-coated nitrogen-carbon substrate; The nitrogen-containing ligand comprises at least one of phenanthroline and dopamine; the pyrolysis temperature is 900-1000 ℃ and the pyrolysis time is 0.5-1.5 h; the solvent comprises a mixed solution of water and ethanol.
  2. 2. The preparation method according to claim 1, wherein the atmosphere of the chemical vapor deposition is a mixed gas of argon and hydrogen, or argon.
  3. 3. The method according to claim 1, wherein when the nitrogen-containing ligand is phenanthroline, the mass ratio of ZIF-8 to the nitrogen-containing ligand is (3-5): 1.
  4. 4. The preparation method of claim 1, wherein the ZIF-8 is prepared by the following process: dissolving zinc nitrate and dimethyl imidazole in methanol solution, and mixing to obtain mixed solution; And (5) sequentially centrifuging and drying the mixed solution to obtain ZIF-8.
  5. 5. The preparation method of claim 4, wherein the mass ratio of zinc nitrate to dimethylimidazole is (4-8): 11-15.
  6. 6. A sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst prepared by the method of any one of claims 1-5, comprising: A nitrogen-coated nitrogen-carbon substrate having a frame structure of regular dodecahedron, wherein the nitrogen-coated nitrogen-carbon substrate has sulfur supported thereon, the sulfur interacting with the nitrogen-coated nitrogen-carbon substrate, and An active center comprising Fe-N 4 supported within the nitrogen-coated nitrogen-carbon substrate.
  7. 7. Use of the Fe-S-N-C cathode oxygen reduction catalyst of claim 6 in a proton exchange membrane fuel cell cathode.

Description

Fe-S-N-C cathode oxygen reduction catalyst doped with iron by sulfur, preparation method and application Technical Field The invention relates to the technical field of catalysts and preparation thereof, in particular to a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst, a preparation method and application thereof. Background Proton Exchange Membrane Fuel Cells (PEMFC) are a new type of energy conversion device, which has received much attention due to their environmental friendliness, low cost, high theoretical energy density, and the like. Oxygen Reduction Reactions (ORR) are the more critical electrochemical reactions in fuel cell applications. Since the reaction involves four electron transfer, the reaction kinetics are slow and the development of higher performance and more stable ORR electrocatalysts is an important point in the development of proton exchange membrane fuel cells. The conventional platinum-based catalyst is expensive due to the rare yield of platinum, which hinders the wide application of proton exchange membrane fuel cells. Therefore, the development of alternative catalysts for non-noble metals is considered to be key to achieving large-scale operation of proton exchange membrane fuel cells. The single-atom catalyst has the advantages of higher atom utilization efficiency, adjustable coordination structure, designable geometric configuration and the like, and has ORR catalytic activity equivalent to that of a platinum-based catalyst in an acidic medium. However, in proton exchange membrane fuel cells, there is still a large gap in membrane electrode performance between the monoatomic catalyst and the platinum-based catalyst. Disclosure of Invention In view of the above, the present invention provides a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst, and a preparation method and application thereof, in order to at least partially solve at least one of the above-mentioned technical problems. According to an embodiment of one aspect of the invention, a preparation method of a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst is provided, which comprises the steps of mixing and pyrolyzing ZIF-8 with a regular dodecahedron framework structure and a nitrogen-containing ligand to form a nitrogen-coated nitrogen-carbon substrate, wherein the nitrogen-carbon substrate has a regular dodecahedron framework structure, and carrying out chemical vapor deposition on a precursor ferric salt, a precursor sulfur salt and the nitrogen-coated nitrogen-carbon substrate to obtain the sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst. According to the embodiment of the invention, the temperature of the chemical vapor deposition is 750-900 ℃ and the time is 2-4 hours, wherein the atmosphere of the chemical vapor deposition is a mixed gas of argon and hydrogen or argon. According to the embodiment of the invention, the ZIF-8 with the regular dodecahedron framework structure and the nitrogen-containing ligand are mixed and pyrolyzed to form the nitrogen-coated nitrogen-carbon substrate, wherein the ZIF-8 and the nitrogen-containing ligand are dissolved in a solvent to obtain a suspension, the suspension is sequentially subjected to rotary evaporation, drying and grinding to obtain the nitrogen-coated ZIF-8, and the nitrogen-coated ZIF-8 is pyrolyzed in a protective atmosphere to obtain the nitrogen-coated nitrogen-carbon substrate, and the nitrogen-containing ligand comprises at least one of phenanthroline and dopamine. According to the embodiment of the invention, the pyrolysis temperature is 900-1000 ℃ and the pyrolysis time is 0.5-1.5 h, and the solvent comprises a mixed solution of water and ethanol. According to the embodiment of the invention, when the nitrogen-containing ligand is phenanthroline, the mass ratio of ZIF-8 to the nitrogen-containing ligand is (3-5): 1. According to the embodiment of the invention, the precursor ferric salt comprises at least one of ferrocene, ferrous chloride and ferrous chloride hydrate, the precursor sulfur salt comprises at least one of thiourea and sublimed sulfur, and the molar ratio of the precursor ferric salt to the precursor sulfur salt to the nitrogen-coated nitrogen-carbon substrate is 1:1 (1.6-3.2). According to the embodiment of the invention, ZIF-8 is prepared by dissolving zinc nitrate and dimethyl imidazole in methanol solution, mixing to obtain a mixed solution, and sequentially centrifuging and drying the mixed solution to obtain ZIF-8. According to the embodiment of the invention, the mass ratio of zinc nitrate to dimethylimidazole is (4-8): 11-15. According to another embodiment of the present invention, there is provided a sulfur-doped iron Fe-S-N-C cathode oxygen reduction catalyst prepared by the above preparation method, comprising a nitrogen-coated nitrogen-carbon substrate having a frame structure of a regular dodecahedron, wherein sulfur is supported on the nitrogen-coated nitrogen-carbon substra