Search

CN-121972200-A - High-temperature stable non-iridium nickel-based catalyst and preparation method thereof

CN121972200ACN 121972200 ACN121972200 ACN 121972200ACN-121972200-A

Abstract

The invention belongs to the technical field of electrocatalytic and functional materials, and relates to a non-iridium nickel-based catalyst stable at high temperature and a preparation method thereof. The catalyst takes a nickel-cobalt layered double hydroxide compound which is modified by in-situ ionic liquid template induced self-limiting domain reconstruction as a main active phase, and 2, 4-dihydroxy-N-trifluoromethyl phenyl acetamide is introduced as an organic synergistic micromolecule to form a conductive framework by being matched with a carbon carrier, a reducing agent and a stabilizing auxiliary agent. The ionic liquid forms a dynamic template in the reaction to realize self-limited domain reconstruction and electron distribution regulation of a lattice structure, so that the composite material with a hierarchical pore structure and an N-doped carbon coating layer is obtained. The catalyst has excellent high-temperature structural stability and electronic conduction performance, and shows low oxygen precipitation overpotential, high specific surface area and good electrochemical cycling stability under alkaline medium. The invention realizes the cooperative promotion of structural stability, conductivity and catalytic activity through an in-situ reconstruction mechanism induced by the ionic liquid template.

Inventors

  • LIU XIANG
  • GUO ZHENBO
  • ZHAO HONGBIN

Assignees

  • 苏州工业园区和顺电气股份有限公司

Dates

Publication Date
20260505
Application Date
20260126

Claims (9)

  1. 1. The high-temperature stable non-iridium nickel-based catalyst is characterized by comprising, by weight, 80-120 parts of a nickel cobalt layered double hydroxide compound modified by self-limiting domain reconstruction induced by an in-situ ionic liquid template, 10-20 parts of 2, 4-dihydroxy-N- (trifluoromethyl phenyl) acetamide, 10-30 parts of a carbon carrier, 3-8 parts of a reducing agent and 2-6 parts of a stabilizing auxiliary agent, wherein the 2, 4-dihydroxy-N- (trifluoromethyl phenyl) acetamide is an organic micromolecule which has a simple structure and contains phenolic hydroxyl and trifluoromethyl substituents.
  2. 2. The high-temperature stable non-iridium nickel-based catalyst is characterized by comprising, by weight, 20-40 parts of nickel nitrate hexahydrate, 10-30 parts of cobalt nitrate hexahydrate, 5-15 parts of imidazolium ionic liquid, 3-10 parts of organic amine complexing agent, 100-200 parts of deionized water, wherein the imidazolium ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, and the organic amine complexing agent is ethylenediamine.
  3. 3. The high temperature stable non-iridium nickel-based catalyst according to any one of claims 1 or 2, wherein the preparation method of the nickel cobalt layered double hydroxide composite modified by in-situ ionic liquid template-induced self-limiting domain reconstruction comprises the following steps: (1) Dissolving nickel nitrate hexahydrate and cobalt nitrate hexahydrate in deionized water, fully stirring to form a uniform solution, then adding ethylenediamine as an organic amine complexing agent, continuously stirring to fully complex metal ions with the complexing agent, then slowly adding 1-butyl-3-methylimidazole hexafluorophosphate ionic liquid, and promoting the system to form stable complex sol under the stirring condition; (2) Transferring the complex sol into a closed reaction kettle, forming a dynamic template in a reaction system by utilizing ionic liquid, and inducing directional assembly of a Ni-Co bimetal layered structure and lattice self-limiting domain reconstruction to obtain a Ni-Co precursor in a gel state; (3) Drying the gel Ni-Co precursor, and then carrying out programmed temperature calcination in an inert atmosphere to partially decompose the ionic liquid cations in the pyrolysis process to generate an N-doped carbon phase coating layer, thereby realizing the redistribution of the structure finite field and the electronic structure and obtaining the nickel-cobalt layered double hydroxide compound modified by the self-finite field reconstruction induced by the in-situ ionic liquid template.
  4. 4. The high-temperature stable non-iridium nickel-based catalyst according to claim 3, wherein the reaction condition of the step (1) is that the uniform and transparent complex sol is formed after the reaction for 2 to 4 hours at 60 to 80 ℃ under the stirring state.
  5. 5. The high temperature stable non-iridium nickel-based catalyst according to claim 3, wherein the reaction condition of the step (2) is that the hydrothermal reaction is carried out for 6-10 hours at 120-150 ℃.
  6. 6. The high temperature stable non-iridium nickel-based catalyst according to claim 3, wherein the reaction condition of the step (3) is that the temperature is raised to 500-650 ℃ at a temperature raising rate of 2-5 ℃ min -1 in a nitrogen or argon atmosphere and the temperature is kept for 2-3 hours.
  7. 7. The high-temperature stable non-iridium nickel-based catalyst according to claim 1 is characterized in that the carbon carrier is formed by mixing conductive carbon black and graphene oxide according to a mass ratio of 3:1, the reducing agent is formed by mixing sodium borohydride and ascorbic acid according to a mass ratio of 2:1, and the stabilizing auxiliary agent is formed by mixing polyvinylpyrrolidone, sodium citrate and ammonia water according to a mass ratio of 2:1:1.
  8. 8. A method for preparing a high temperature stable non-iridium nickel-based catalyst, wherein the high temperature stable non-iridium nickel-based catalyst is as claimed in any one of claims 1 to 7, comprising the steps of: s1, adding a nickel-cobalt layered double hydroxide compound which is modified by in-situ ionic liquid template-induced self-limiting domain reconstruction, 2, 4-dihydroxy-N- (trifluoromethyl) phenylacetamide, a carbon carrier, a reducing agent and a stabilizing additive into an isopropanol solvent, and stirring and dispersing to form uniform mixed slurry; S2, placing the uniformly mixed slurry in a rotary evaporation device, and removing a solvent and loading the solvent on the surface of the organic micromolecule to enable the solvent and the surface of the compound to have a hydrogen bond-pi conjugation effect to obtain a solid; and S3, carrying out vacuum drying and low-temperature roasting treatment on the solid in an inert atmosphere to obtain the non-iridium nickel-based catalyst with high temperature stability.
  9. 9. The preparation method of the high-temperature stable non-iridium nickel-based catalyst according to claim 8, wherein the reaction condition of the step S1 is stirring and dispersing for 1-2 hours at 25-40 ℃ under magnetic stirring, the reaction condition of the step S2 is rotary evaporation at 50-70 ℃ under reduced pressure, the vacuum degree is controlled to be minus 0.08-minus 0.09MPa, and the reaction condition of the step S3 is that the temperature is raised to 300-400 ℃ at a heating rate of 2-3 ℃ min -1 in nitrogen or argon atmosphere and the temperature is kept for 1-2 hours.

Description

High-temperature stable non-iridium nickel-based catalyst and preparation method thereof Technical Field The invention belongs to the technical field of electrochemical catalytic materials, and particularly relates to a non-iridium nickel-based catalyst stable at high temperature and a preparation method thereof. Background Electrochemical oxygen evolution reactions and hydrogen evolution reactions are key steps in water electrolysis, fuel cells, and renewable energy conversion systems. The existing iridium-based or ruthenium-based noble metal oxide catalyst has high catalytic activity, but is easy to generate structural decay under high temperature or strong alkaline environment due to scarce noble metal resources and high price, so that the stability and economy of the catalyst are difficult to meet the industrial requirements. In contrast, non-noble metal-based catalysts, in particular Ni, ni-Fe, ni-Co layered double hydroxide systems based on nickel, are considered as potential materials for replacing noble metal catalysts due to their low cost, good electrical conductivity, and adjustable valence state. However, the conventional Ni-Co layered double hydroxide catalyst still has the problems of structure and performance decay under the conditions of high temperature and long-term electrochemical reaction. The layered skeleton is easy to collapse or convert into inert oxide, which causes insufficient exposure of active center, unstable metal-oxygen bond electron structure and reduced charge migration efficiency, and meanwhile, the interface binding force between the carrier and the active component is weaker, which is easy to cause the phenomena of particle agglomeration, sintering, inactivation and the like, and seriously affects the catalytic life and high-temperature stability of the material. The existing researches generally improve the problems by means of doping regulation, heterogeneous coating, carbon material compounding and the like, but most of the means rely on exogenous carbonization or aftertreatment coating, and in-situ regulation and control on lattice structures and electron energy levels cannot be realized in the material growth process, so that high-temperature structural stability and electron conduction continuity are difficult to be considered. Therefore, in the field of electrochemical energy conversion, a new modification path capable of realizing lattice confinement, defect regulation and electronic structure collaborative reconstruction in the synthesis stage is still needed to further improve the high-temperature stability and electrochemical activity of the non-noble metal catalyst. Disclosure of Invention In order to overcome the technical problems that the existing Ni-Co layered double hydroxide catalyst is easy to generate structural collapse, limited in electron conduction and attenuated in activity under high temperature and strong alkali conditions, the invention aims to provide a high-temperature stable non-iridium nickel-based catalyst and a preparation method thereof, so that the material can still maintain excellent structural integrity and long-term catalytic stability in a high-temperature electrochemical environment. The invention adopts an in-situ ionic liquid template-induced self-limiting domain reconstruction modification technology, introduces imidazolium ionic liquid as a dynamic template and a charge regulating medium in the formation process of nickel cobalt layered double hydroxide, realizes lattice self-limiting domain reconstruction and electron structure optimization by the directional induction effect of the ionic liquid and the coating of an N-doped carbon layer formed by subsequent thermal decomposition, and simultaneously introduces 2, 4-dihydroxy-N- (trifluoromethyl) phenylacetamide as a surface organic micromolecule stabilizer to form a hydrogen bond-pi conjugated protective layer on the surface of the material so as to enhance conductivity and oxidation resistance. The catalyst prepared by the invention has the advantages of stable high-temperature structure, continuous electron conduction, firm interface combination and high electrochemical activity retention rate. The aim of the invention can be achieved by the following technical scheme: the high-temperature stable non-iridium nickel-based catalyst comprises, by weight, 80-120 parts of nickel-cobalt layered double hydroxide compound subjected to in-situ ionic liquid template induced self-limiting domain reconstruction modification, 10-20 parts of 2, 4-dihydroxy-N- (trifluoromethyl phenyl) acetamide, 10-30 parts of carbon carrier, 3-8 parts of reducing agent and 2-6 parts of stabilizing auxiliary agent, wherein the 2, 4-dihydroxy-N- (trifluoromethyl phenyl) acetamide is an organic micromolecule which has a simple structure and contains phenolic hydroxyl and trifluoromethyl substituent groups. The nickel-cobalt layered double hydroxide compound which is modified by in-situ ionic liquid templat