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KR-20260065166-A - Control method for dispersion of dual-atom catalysts, dual-atom catalyst with improved dispersion, and manufacturing method thereof

KR20260065166AKR 20260065166 AKR20260065166 AKR 20260065166AKR-20260065166-A

Abstract

The present invention relates to a method for controlling the dispersion of a diatomaceous atomic catalyst, a diatomaceous atomic catalyst with improved dispersion, and a method for manufacturing the same. More specifically, the invention relates to a method for controlling the dispersion of diatomaceous atomic

Inventors

  • 김현탁
  • 김상준
  • 박지훈
  • 유영우
  • 이진희
  • 박민주
  • 김민철
  • 신재호
  • 김경민

Assignees

  • 한국화학연구원

Dates

Publication Date
20260508
Application Date
20241101

Claims (12)

  1. A method for controlling the dispersion of diatomes in a catalyst in which different types of catalytically active metals are dispersed as diatomes and supported on a nitrogen-doped carbon material, wherein A method for controlling the dispersion of diatomaceous atoms in a catalyst, characterized by controlling the dispersion of diatomaceous atoms in a diatomaceous catalyst by changing the heating rate during the process of preparing a diatomaceous catalyst by heating a dispersion of catalyst precursors containing a first organometallic compound, a second organometallic compound, and colloidal silica to a thermal decomposition temperature and then thermally decomposing it.
  2. In paragraph 1, A method for controlling the dispersion of diatomaceous atoms in a catalyst, characterized in that the first organometallic compound and the second organometallic compound contain any one of phthalocyanine, porphyrin, and porphyrazine in their structure.
  3. In paragraph 1, A method for controlling the dispersion of diatomaceous atoms in a catalyst, characterized in that the above-mentioned catalyst precursor dispersion is obtained by mixing and dispersing a first organometallic compound, a second organometallic compound, and colloidal silica in an organic solvent, and then removing the organic solvent until the ratio of the remaining solvent is 5 to 15 wt% of the total solution.
  4. In paragraph 3, A method for controlling the dispersion of diatomaceous atoms in a catalyst, characterized in that the above organic solvent is a mixture of ethanol and DMF.
  5. In paragraph 4, A method for controlling the dispersion of diatomaceous atoms in a catalyst, characterized in that the relative volume ratio of ethanol per unit volume of DMF (ethanol/DMF) is in the range of 0.2 to 5.
  6. (a) a step of providing a catalyst precursor dispersion in which a catalyst precursor mixture comprising a first organometallic compound, a second organometallic compound, and colloidal silica is dispersed in an organic solvent; (b) a step of removing the solvent from the catalyst precursor dispersion to a predetermined level; (c) a step of obtaining a pyrolysis product by heating the catalyst precursor dispersion after step (b) at a rate of 2.0 to 4.5 ℃/min to a pyrolysis temperature under an inert gas atmosphere and then pyrolyzing for a predetermined time; and (d) a step of obtaining a diatomaceous atom catalyst in which diatomaceous atoms are dispersed on a nitrogen-doped carbon material by removing colloidal silica from the above pyrolysis product; characterized by comprising a method for producing a diatomaceous atom catalyst with improved dispersion.
  7. In paragraph 6, A method for preparing a diatomaceous atomic catalyst with improved dispersion, characterized in that the first organometallic compound and the second organometallic compound of step (a) above contain any one of phthalocyanine, porphyrin, and porphyrazine in their structure.
  8. In paragraph 6, A method for preparing a diatomaceous atomic catalyst with improved dispersion, characterized in that the above organic solvent is a mixture of ethanol and DMF.
  9. In paragraph 8, A method for producing a diatomaceous atomic catalyst with improved dispersion, characterized in that the relative volume ratio of ethanol per unit volume of DMF (ethanol/DMF) is in the range of 0.2 to 5.
  10. In paragraph 6, A method for preparing a diatomaceous atomic catalyst with improved dispersion, characterized in that in step (b) above, the removal of the solvent is performed such that the ratio of the solvent in the dispersion is in the range of 5 to 15 wt%.
  11. In paragraph 6, A method for producing a diatomaceous atomic catalyst with improved dispersion, characterized in that the pyrolysis of step (c) above is performed in the range of 600 to 900 ℃.
  12. A diatomaceous atomic catalyst with improved dispersion, characterized by being manufactured by the manufacturing method of any one of claims 6 to 11.

Description

Control method for dispersion of dual-atom catalysts, dual-atom catalyst with improved dispersion, and manufacturing method thereof The present invention relates to a method for controlling the dispersion of a diatomaceous atomic catalyst, a diatomaceous atomic catalyst with improved dispersion, and a method for manufacturing the same. More specifically, the invention relates to a method for controlling the dispersion of diatomaceous atomic Catalysts are key materials for improving efficiency in the chemical and energy-based industries. The size of the catalytic active site significantly influences reactivity and catalyst costs. Consequently, efforts have been made to enhance the specific surface area and activity of these catalysts by minimizing the active site from bulk to single-atom levels while increasing the dispersion of active metals. Although single-atom catalysts (SACs), which have been actively researched recently, have shown remarkable performance in thermochemical and electrochemical reactions, it has been pointed out that there is a limitation in that it is difficult to increase the concentration (area ratio density) of single-atom active sites as the thermodynamic structural stability decreases as the catalyst site becomes smaller. Accordingly, a dual atom catalyst (DAC) structure was proposed as the next generation of the above SAC, and a theory was reported that the heteroatom dual atom active site imparts a multi-active, stable binding mode to the reactants and enhances the binding energy through d-band center shifting between active atoms. The development of the aforementioned DAC is in its very early stages, and to date, top-down or bottom-up approaches are known for DAC manufacturing. The above top-down method can be exemplified by a method in which a support composed of multiple layers, such as graphite, is exfoliated into a single layer, and then a metal is doped into the single layer of the support using ligands, etc. There is an example in Chinese Patent Publication 115094442 A (published September 23, 2022) in which nitrogen ligands and metal precursors are introduced into graphene, which serves as the support. While the above top-down method has the advantage of being similar to conventional methods of supporting metal on a support, it is difficult to control the dispersion of the doped metal, which can lead to the problem of the metal existing in a cluster form rather than atomic units. On the other hand, the above bottom-up method can be exemplified by a method in which a precursor contained within the structure is introduced together with other support materials and then converted into a monolayer matrix form through thermal, chemical, or electrical treatment. There is an example in Non-Patent Literature 1 (Dazhi Yao et al. (2023)) in which a DAC for CO2 reduction reaction with metal supported on graphene nanosheets is prepared by mixing a metal chloride with the support materials dicyandiamide and glucose and then heat-treating them. This bottom-up method has the advantage of easily solving the metal dispersibility problem of the top-down method. However, despite the development of the aforementioned bottom-up method, there has been little technological development regarding sophisticated and reproducible methods for controlling the dispersion of DACs and methods for manufacturing DACs with improved dispersion, so improvements are still needed. Figure 1 is a schematic diagram showing the structure of a diatomaceous atom of the catalyst of the present invention. Figure 2(a) is a bottom-up process for manufacturing a biatom catalyst as an example of the present invention, (b) is a schematic diagram of a top-down process for manufacturing a nanoparticle catalyst as Comparative Example 1, (c) to (g) are super-high resolution Cs-corrected HAADF-STEM analysis images and elemental mapping images of CuNi biatoms and CuNi nanoparticles based on Energy dispersive X-ray spectroscopy, and (e) and (g) are electron energy loss signal (EEL) images as a function of spectral scanning vectors for CuNi biatoms and CuNi nanoparticles, respectively. Figure 3(a) shows the statistical ratio of the diatomaceous and single atoms of the catalyst of Example 1 of the present invention compared in an EDS system, and (b) shows the results of the analysis of the interatomic distance of the copper-nickel diatomaceous atoms through kernel density distribution statistics. Figure 4 shows a STEM image of a DAC sample synthesized under heating rate conditions (1.5~3.5 ℃/min). Figure 5 shows the HADDF-STEM/EDS image of a DAC sample synthesized under a heating rate (5 ℃/min). Figure 6 shows the product selectivity in the RWGS reaction of DAC synthesized under heating rate conditions (1.5~3.5 ℃/min). Figure 7 shows the results of analyzing the electronic states and metal-to-metal interactions of each sample through X-ray absorption microstructure (XAFS) spectroscopy. Figure 8 compares structural models of single-ato