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CN-122025679-A - Ultra-high density diatomic mesoporous carbon catalyst and preparation method and application thereof

CN122025679ACN 122025679 ACN122025679 ACN 122025679ACN-122025679-A

Abstract

The invention belongs to the technical field of preparation of catalytic materials, and particularly relates to an ultrahigh-density diatomic mesoporous carbon catalyst, and a preparation method and application thereof. The ultra-high density diatomic mesoporous carbon catalyst provided by the invention comprises a monodisperse mesoporous nitrogen doped carbon nanosphere carrier, and first metal atoms and second metal atoms which are atomically dispersed on the mesoporous carbon carrier, wherein the first metal atoms comprise Pt, the second metal atoms comprise at least one of Co, fe, ni, cu, mn and Zn, the first metal atoms and the second metal atoms form an atom pair with a distance of less than 0.3 nm, the total loading amount of the first metal single atoms and the second metal single atoms is 5-7 wt percent, the site density can reach 3-5 per square nanometer, and the pairing rate of the first metal atoms and the second metal atoms can reach 50-60 percent. The catalyst solves the problems of low metal atom loading, low active site density, nonuniform structure and difficult precise regulation and control existing in the prior art.

Inventors

  • Huang Senchuan
  • Cao Yangfei
  • LUO ZICHAO
  • ZHANG SHANQING

Assignees

  • 广东工业大学

Dates

Publication Date
20260512
Application Date
20260212

Claims (10)

  1. 1. The ultra-high density diatomic mesoporous carbon catalyst is characterized by comprising a monodisperse mesoporous nitrogen doped carbon nanosphere carrier, and first metal atoms and second metal atoms which are atomically dispersed on the mesoporous carbon carrier; the first metal atom includes a platinum atom, and the second metal atom includes at least one of Co, fe, ni, cu, mn and Zn; The first metal atom and the second metal atom form an atom pair with a distance less than 0.3 nm, and the first metal monoatom and the second metal monoatom; the total metal atom load in the ultra-high density diatomic mesoporous carbon catalyst is 5-7 wt%, the site density can reach 3-5 per square nanometer, and the pairing rate of the first metal atom and the second metal atom can reach 50-60%.
  2. 2. A method for preparing the ultra-high density diatomic mesoporous carbon catalyst of claim 1, comprising the steps of: dispersing monodisperse medium Kong Mian resin nanospheres in water, then adding first metal salt and ethylene glycol to perform a first reaction, and then adding second metal salt to perform a second reaction to obtain a compound precursor; and carrying out pyrolysis treatment on the compound precursor in an inert atmosphere to obtain the ultra-high density diatomic mesoporous carbon catalyst.
  3. 3. The method of claim 2, wherein the mass to volume ratio of monodisperse mesoporous Kong Mian resin nanospheres to water is 200 mg:45 mL.
  4. 4. The method of claim 2, wherein the first metal salt comprises chloroplatinic acid, added as an aqueous solution, at a concentration of 0.02 mol/L; And/or, the second metal salt comprises at least one of Co, fe, ni, cu, mn and Zn soluble chloride, and is added in the form of aqueous solution with the concentration of 0.02 mol/L.
  5. 5. The method of claim 4, wherein the monodisperse mesoporous Kong Mian resin nanospheres, the first metal salt and the ethylene glycol are used in an amount ratio of 200 mg (0.08-0.15) mL (2-6) mL; And/or the dosage ratio of the monodisperse medium Kong Mian resin nanospheres to the second metal salt is 200 mg (0.15-0.30) mL.
  6. 6. The method of claim 2, wherein the first reaction is performed for a period of 3 h; And/or the time of the second reaction is 3 h.
  7. 7. The method according to claim 2, wherein the pyrolysis treatment is performed by heating to 350 ℃ at a heating rate of 1 ℃ per minute, incubating the reaction mixture for 2-3h, heating to 700-1000 ℃ at a heating rate of 10 ℃ per minute, and incubating the reaction mixture for 2-h.
  8. 8. The method of preparing as claimed in claim 2, wherein the preparing step of the monodisperse mesoporous Kong Mian resin nanospheres comprises: mixing the segmented copolymer with water, adding pore-enlarging agent mesitylene, and uniformly mixing to obtain micelle template solution; adding melamine and formaldehyde into water, and adding inorganic base for prepolymerization reaction to obtain melamine-formaldehyde oligomer emulsion; Mixing the micelle template solution with the melamine-formaldehyde oligomer emulsion, and stirring to obtain a compound micelle solution; Adding hydrochloric acid into the composite micelle solution to perform secondary polymerization reaction to obtain the monodisperse mesoporous Kong Mian resin nanospheres.
  9. 9. The method of claim 8, wherein the block copolymer comprises Pluronic F127 and/or Pluronic P123; And/or the concentration of the block copolymer in the micelle template solution is (0.03-0.09) g/mL; And/or the mass ratio of the block copolymer to the pore-expanding agent mesitylene is 1 (0.5-1.5); And/or, the formaldehyde is added in the form of an aqueous solution with a concentration of 37 wt%; And/or the inorganic base comprises at least one of sodium hydroxide, potassium hydroxide and ammonia water, and is added in the form of an aqueous solution with the concentration of (0.06-0.15) mol/L; And/or the concentration of melamine in the melamine-formaldehyde oligomer emulsion is (6-12) mg/mL; And/or the mole ratio of melamine, formaldehyde and inorganic base is 1 (0.5-1.5): 0.00025-0.0015; And/or the reaction temperature of the prepolymerization reaction is 100 ℃ and the time is 30 min; And/or the volume ratio of the micelle template solution to the melamine-formaldehyde oligomer emulsion in the composite micelle solution is (5-15) mL, 40 mL; And/or the concentration of the hydrochloric acid is 0.2-0.7 mol/L; and/or the mol ratio of the hydrochloric acid to the melamine is 1 (0.2-0.5); And/or the temperature of the secondary polymerization reaction is 100 ℃ and the time is 4-8 h.
  10. 10. Use of the ultra-high density diatomic mesoporous carbon catalyst of claim 1 in electrocatalytic oxygen reduction reactions.

Description

Ultra-high density diatomic mesoporous carbon catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of preparation of catalytic materials, and particularly relates to an ultrahigh-density diatomic mesoporous carbon catalyst, and a preparation method and application thereof. Background Atomically dispersed metal catalysts, particularly monoatomic catalysts, are of great interest because of their extremely high atom utilization and defined active sites. However, for reactions requiring synergy between adjacent sites (e.g., fuel cell cathodic oxygen reduction), the single-atom catalyst is limited by its single active center structure, which presents an inherent bottleneck in activity and selectivity. The diatomic catalyst provides possibility for breaking the bottleneck and realizing synergistic catalysis by constructing a pair of adjacent metal active sites. In addition, the diatomic catalyst provides stronger flexibility in regulating the chemical composition of active sites, coordination environment and interaction of double sites, and greatly widens the design space of heterogeneous catalytic reaction. Currently, the preparation of diatomic catalysts generally relies on the capture of metal precursors at randomly distributed limited anchor sites on a support, which results in three general difficulties: (1) The lack of specific anchor points simultaneously constrains two metal atoms, so that the configuration, the spacing and the spatial distribution of the double-atom active center are difficult to realize accurate regulation and control; (2) To inhibit agglomeration of metal atoms during pyrolysis, it is often necessary to sacrifice metal loading (typically <3 wt%), resulting in low active site density; (3) The difference in microenvironment of the anchor sites themselves on the support can easily lead to non-uniformity in the finally formed diatomic site coordination structure. Therefore, developing a universal method capable of realizing high-density, high-load and high-uniformity double-atomic-site accurate construction is a technical problem to be broken through in the field. Disclosure of Invention The invention aims to provide an ultrahigh-density diatomic mesoporous carbon catalyst, and a preparation method and application thereof, so as to solve the problems in the prior art. In order to achieve the above object, the present invention provides the following solutions: The invention provides an ultra-high density diatomic mesoporous carbon catalyst, which comprises a monodisperse mesoporous nitrogen doped carbon nanosphere carrier, and first metal atoms and second metal atoms which are atomically dispersed on the mesoporous carbon carrier; The first metal atoms include platinum (Pt) atoms, and the second metal atoms include at least one of Co, fe, ni, cu, mn and Zn; The first metal atom and the second metal atom form an atom pair with a distance less than 0.3 nm, and the first metal monoatom and the second metal monoatom; the total metal atom load in the ultra-high density diatomic mesoporous carbon catalyst is 5-7 wt%, the site density can reach 3-5 per square nanometer, and the pairing rate of the first metal atom and the second metal atom can reach 50-60%. The second technical scheme of the invention provides a preparation method of the ultra-high density diatomic mesoporous carbon catalyst, which comprises the following steps: dispersing monodisperse medium Kong Mian resin nanospheres in water, then adding first metal salt and ethylene glycol to perform a first reaction, and then adding second metal salt to perform a second reaction to obtain a compound precursor (medium Kong Mian resin containing bimetallic ions); and carrying out pyrolysis treatment on the compound precursor in an inert atmosphere to obtain the ultra-high density diatomic mesoporous carbon catalyst. Further, the mass-volume ratio of the monodisperse mesoporous Kong Mian resin nanospheres to water is 200 mg/45 mL. Further, the first metal salt comprises chloroplatinic acid, and is added in the form of an aqueous solution at a concentration of 0.02 mol/L. Further, the dosage ratio of the monodisperse medium Kong Mian resin nanospheres to the first metal salt to the ethylene glycol is 200 mg (0.08-0.15) mL (2-6) mL. Further, the second metal salt comprises at least one of Co, fe, ni, cu, mn and Zn soluble chloride, and is added in the form of aqueous solution with the concentration of 0.02 mol/L. Further, the dosage ratio of the monodisperse mesoporous Kong Mian resin nanospheres to the second metal salt is 200 mg (0.15-0.30) mL. Further, the time of the first reaction was 3 h. Further, the second reaction time was 3 h. Further, the pyrolysis treatment is carried out by heating to 350 ℃ at a heating rate of 1 ℃ per minute, reacting at a temperature of 2-3 h, heating to 700-1000 ℃ at a heating rate of 10 ℃ per minute, and reacting at a temperature of 2-h. Further, th