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CN-122025676-A - Oxygen reduction catalyst based on Nb-oxyfluoride cluster confinement and pulse-induced ordering and preparation method and application thereof

CN122025676ACN 122025676 ACN122025676 ACN 122025676ACN-122025676-A

Abstract

The invention discloses an oxygen reduction catalyst based on Nb-oxyfluoride cluster confinement and pulse induction ordering, and a preparation method and application thereof. The preparation method of the platinum-based multi-element alloy catalyst comprises the following steps of S1, adding niobium ammonium fluoride and hydrogen peroxide into a dispersion liquid containing a carbon carrier for reaction so as to introduce Nb-oxyfluoride clusters on the surface of the carbon carrier in situ, S2, adding a platinum source, a cobalt source and a nickel source into a product obtained in the step S1, then adding ascorbic acid and sodium borohydride for reaction to obtain Pt-Co-Ni alloy particles with Nb-oxyfluoride cluster limited domains, and S3, carrying out pulse Joule heating treatment on the product obtained in the step S2 so as to convert the alloy from a disordered structure to an ordered L1 2 phase, thereby obtaining the platinum-based multi-element alloy catalyst. The catalyst of the invention shows excellent oxygen reduction reaction activity and long-term stability in the application of a proton exchange membrane fuel cell cathode.

Inventors

  • HUANG GUOYONG
  • ZENG YIFENG
  • CUI JIAN
  • LIU YUCHUN

Assignees

  • 中国石油大学(北京)

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. A method for preparing a platinum-based multi-component alloy catalyst, comprising the steps of: S1, adding niobium ammonium fluoride and hydrogen peroxide into a dispersion liquid containing a carbon carrier to react so as to introduce Nb-oxyfluoride clusters on the surface of the carbon carrier in situ; s2, adding a platinum source, a cobalt source and a nickel source into the product obtained in the step S1, and then adding ascorbic acid and sodium borohydride to react to obtain Nb-oxyfluoride cluster limited Pt-Co-Ni alloy particles; And S3, carrying out pulse Joule heating treatment on the product obtained in the step S2 to convert the alloy from a disordered structure into an ordered L1 2 phase, thereby obtaining the platinum-based multi-element alloy catalyst.
  2. 2. The method according to claim 1, wherein the carbon carrier comprises one or more of carbon black, N-doped graphene, carbon nanotubes, and graphene oxide; And/or the carbon carrier is carbon black, and the method further comprises the step of pretreating the carbon black by treating the carbon black for 1-2 hours at 700-900 ℃ in an inert atmosphere, dispersing the carbon black in 0.05-0.2M nitric acid solution after cooling, and refluxing for 2-4 hours at 70-100 ℃.
  3. 3. The preparation method of any one of claims 1-2, wherein the mass ratio of the carbon carrier to the niobium ammonium fluoride is 2 (0.3-0.6); and/or adding 5-10 mL of 30% hydrogen peroxide aqueous solution into each 2g of carbon carrier; And/or in the step S1, the reaction temperature is 50-80 ℃ and the reaction time is 1-3 h.
  4. 4. The method according to any one of claims 1 to 3, wherein the molar ratio of the platinum source, the cobalt source and the nickel source is 1 (0.2 to 0.3): 0.05 to 0.3 in terms of metal; and/or the ratio of the carbon carrier to the platinum element in the platinum source is 2g (0.1-0.3) mmol; and/or the platinum source is selected from one or more of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate and ammonium chloroplatinate; And/or the cobalt source is selected from one or more of cobalt chloride, cobaltous chloride and sodium cobaltate chloride; And/or the nickel source is selected from nickel nitrate, nickel chloride and sodium chloronickelate.
  5. 5. The method according to claim 4, wherein the ascorbic acid is added as an aqueous solution thereof, the ratio of the platinum source to the ascorbic acid solution is 0.1 mmol:5-30 mL, and the concentration of the ascorbic acid solution is 0.05M-0.5M.
  6. 6. The method according to claim 4 or 5, wherein the sodium borohydride is added in the form of an aqueous solution thereof, the ratio of the platinum source to the sodium borohydride solution is 0.1 mmol/4 to 15mL, and the concentration of the sodium borohydride solution is 0.02M to 0.1M.
  7. 7. The method of any one of claims 1 to 6, wherein in the pulse Joule heating step, the pulse width is 100 to 500 microseconds, the pulse current is 5 to 15A, the heating time is 1 to 1.5 milliseconds, and the temperature is 850 to 950 ℃.
  8. 8. The method according to any one of claims 1 to 7, wherein the method further comprises the step of acid washing the product obtained in the step S3 or subjecting the product to an acidic solution for electrochemical recycling treatment after the step S3.
  9. 9. A platinum-based multi-alloy catalyst prepared by the method of any one of claims 1-8.
  10. 10. Use of the platinum-based multi-alloy catalyst according to claim 9 for catalyzing an oxygen reduction reaction.

Description

Oxygen reduction catalyst based on Nb-oxyfluoride cluster confinement and pulse-induced ordering and preparation method and application thereof Technical Field The invention belongs to the technical field of electrochemical energy materials, in particular to a platinum-based multielement alloy electrocatalyst and a preparation method thereof, and particularly relates to an oxygen reduction reaction catalyst for realizing structural ordering through limited-area regulation and control and pulse treatment. Background The fuel cell is a clean energy conversion device capable of efficiently and directly converting fuel chemical energy into electric energy, and has important strategic significance in the construction of a green low-carbon energy system. In particular to a Proton Exchange Membrane Fuel Cell (PEMFC), which has low working temperature, high energy conversion efficiency, high response speed and compact structure, and has wide application prospect in the fields of transportation, stationary power generation, portable power supply and the like. However, the large-scale industrialization of fuel cells is still limited by critical materials, with slow kinetics of the cathodic Oxygen Reduction Reaction (ORR) being the most significant bottleneck problem. How to develop electrocatalysts with both high activity and high stability is one of the core challenges in pushing the advancement of fuel cell technology. Currently, platinum and its alloys remain the most effective oxygen reduction catalysts, and carbon-supported platinum nanoparticles are commonly employed as cathode catalysts for commercial fuel cells. However, the single-metal platinum has the problems of high noble metal usage, limited specific activity, easy dissolution and agglomeration in the long-time operation process and the like in an acidic medium. These drawbacks not only lead to a significant increase in the consumption of platinum resources, but also make it difficult for the durability of the fuel cell in long-term operation to meet the demands of commercial applications. To overcome these problems, researchers have proposed various improvement strategies. One common approach is to introduce transition metal elements into the platinum lattice by alloying means to regulate the electronic structure and surface adsorption properties of the platinum, thereby optimizing the reaction path of the oxygen reduction reaction. The elements such as nickel, cobalt, iron, copper, chromium and the like are widely applied to alloying research, and the activity and the utilization rate of the catalyst can be improved to a certain extent. However, conventional alloy catalysts often face serious stability problems under practical fuel cell operating conditions, the base metal is easily dissolved in the acid electrolyte, active sites are lost, and the particles are sintered or agglomerated at high potential, so that the long-term stability of the catalyst is significantly reduced. Another direction of development is monoatomic catalysts. By dispersing the metal atoms in monoatomic form on a carbon support or doped substrate, the atom utilization can be significantly improved, achieving nearly one hundred percent active site exposure. Such materials theoretically have excellent mass activity and lower noble metal requirements, and exhibit certain advantages in oxygen reduction reactions. However, the single-atom catalyst still has the defects in practical application, the structure of the single-atom catalyst is often not stable enough in a complex electrochemical environment, migration and agglomeration are easy to occur, and single atoms gradually evolve into small clusters or nano particles, so that long-term performance is reduced. In addition, the synthesis method of the monoatomic catalyst has strict requirements on conditions, and usually requires special defect sites or coordination structures to stabilize monoatoms, so that the controllability of the process and the feasibility of large-scale production are difficult to ensure. Yet another improvement is to increase the loading of noble metals on the carbon support, and to increase the apparent activity of the catalyst by increasing the overall platinum content. In this strategy, noble metals are typically deposited uniformly on the carbon support surface using a variety of wet chemistry methods, and particle size and distribution are controlled by optimizing the reaction conditions. The high-loading catalyst can improve the initial activity to a certain extent, but agglomeration and oswald ripening are easily caused due to the reduction of the inter-particle distance, so that the specific surface area of the catalyst is reduced, and finally the utilization rate of noble metal is reduced. Meanwhile, the method often needs complex pretreatment steps and long synthesis period, and has certain limitation in process. Existing oxygen reduction catalyst research is mainly focused on three directions of