A method for preparing metal single-atom materials based on electron beam irradiation and its application

Abstract

The present invention discloses a method for preparing a metal single-atom material based on electron beam irradiation, wherein an aryl metal coordination compound containing heteroatoms is used as a raw material and is irradiated with an electron beam under vacuum or inert gas protection; the aryl metal coordination compound containing heteroatoms has a metal atom as a central atom, and the central atom is directly or indirectly connected to at least two benzene rings or heteroatom-substituted benzene-like rings, wherein at least one heteroatom-substituted benzene-like ring is connected; the heteroatom is N, P, O or S. The obtained metal single-atom material is used as a catalyst. The present invention not only simplifies the process flow and reduces the preparation cost, but also provides a more environmentally friendly and efficient solution for the design and application of metal single-atom materials, and is particularly suitable for energy conversion, environmental governance, catalysis, biology and other fields.

Description

Technical Field

[0001] The present invention belongs to the field of material technology, and in particular relates to a method for preparing a metal single-atom material based on electron beam irradiation, and applications of the metal single-atom material. Background Art

[0002] Metal single-atom materials have broad application prospects, especially in the field of catalysts. The preparation methods of traditional metal single-atom materials usually rely on complex processes such as carrier anchoring, high-temperature pyrolysis or chemical reduction. Although these methods can achieve the dispersion of metal atoms to a certain extent, they have many limitations. First, the process complexity is significant and requires multiple steps, such as ligand modification, acid and alkali washing, solvent treatment, and high-temperature treatment, which not only increases the preparation cost, but may also cause metal atom agglomeration and reduce the activity and stability of the catalyst. Secondly, the carrier dependence is high, and the dispersion and stability of metal atoms are often limited by the carrier material, and the carrier itself may introduce impurities, affecting the performance of the catalyst. In addition, traditional methods usually require high temperature conditions, huge energy consumption, and may involve toxic solvents, acid and alkali post-treatment, and complex chemical reduction steps. These processes are not only cumbersome, but may also pollute the environment and increase energy waste.

[0003] For example, CN119852426A discloses an ordered macroporous carbon-supported bimetallic single-atom catalyst, a preparation method and an application thereof, wherein the preparation method comprises the following steps: S1, synthesizing a polymer microsphere template, preparing a first transition metal-organic precursor solution, placing the polystyrene sphere template in the first transition metal-organic precursor solution and immersing it at room temperature for 2 hours to obtain product A; S2, vacuum degassing the product A, filtering it and drying it in an oven overnight, and placing it in a mixture of ammonia water and methanol in a volume ratio of 1:1. : (0.8-1.2) solution is vacuum degassed, immersed at room temperature for 20-30h, filtered to obtain the impregnated template, and dried in a box overnight to obtain a precursor-filled microsphere template; S3, the microsphere template filled with the precursor liquid is placed in a tubular furnace, an inert gas is introduced, and calcined to obtain product B; S4, the product B is mixed with the second transition metal precursor liquid, aged, centrifuged, dried, and placed in a tubular furnace, an inert gas is introduced, and calcined at 600-1000°C for 2-4h. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing metal single-atom materials based on electron beam irradiation, so as to achieve rapid and efficient preparation of metal single-atom materials without the need for a carrier, high temperature, or complex post-processing.

[0005] The technical solution adopted by the present invention is as follows: a method for preparing metal single-atom materials based on electron beam irradiation, using an aromatic metal coordination compound containing heteroatoms as a raw material and irradiating with an electron beam under vacuum or inert gas protection; the aromatic metal coordination compound containing heteroatoms has a metal atom as a central atom, and the central atom is directly or indirectly connected to at least two benzene rings or heteroatom-substituted benzene-like rings, wherein at least one heteroatom-substituted benzene-like ring is; the heteroatom is N, P, O or S.

[0006] Furthermore, the heteroatom-containing aromatic metal coordination compound is selected from bis(4,6-difluorophenylpyridine-N,C2)pyridinecarbonyl iridium, methyl(triphenylphosphine)gold(I), bis(dithiobenzil)nickel, MOF:MIL-88B(Fe), tris(2-(4-fluorophenyl)pyridine)iridium, trifluoromethyl(1,10-phenanthroline)copper(I), tris(triphenylphosphine)ruthenium(II)dichloride, bis(triphenylphosphine)cobalt chloride, Fe phthalocyanine, Cu phthalocyanine, Pd phthalocyanine, heme, vitamin B12, 1,2-bis(diphenylphosphine)ethanenickel(II)chloride, tetrakis(triphenyl)phosphine palladium, tetrakis(triphenyl)phosphine ruthenium or hexapyridine iridium.

[0007] The amount of the raw material is 1-100 mmol, the energy of the electron beam is 50 eV-100 keV, and the beam current density is 10-50 mc / cm 2 , irradiation time 1-50 minutes.

[0008] The metal single atom material obtained by the above method is used as a catalyst.

[0009] The reaction mechanism of this invention is as follows: a high-energy electron beam first cleaves C-H bonds in the aromatic ring, generating carbon radicals (C·). These radicals then recombine at adjacent positions to form new C-C bonds, thereby forming a metal single-atom material and an organic polymeric support with a highly dispersed metal single-atom structure. This process not only achieves extremely high dispersion and utilization of the metal atoms, but also ensures the stability and activity of the catalyst.

[0010] Compared with traditional methods, the present invention has significant beneficial effects: no carrier is required, and the metal atoms are directly anchored in the in situ generated carbon matrix; no reducing agent, solvent, high-temperature pyrolysis or acid-base post-treatment is required, achieving true one-step formation; the metal-carbon interaction is precisely controlled by the electron beam, suppressing the agglomeration of metal atoms, and the metal atoms in the single-atom material are extremely dispersed, with an atomic utilization rate of almost 100%; the entire process has no chemical waste emissions, low energy consumption, and the reaction is almost instantaneous, with extremely high efficiency. This innovative preparation method not only simplifies the process flow and reduces preparation costs, but also provides a more environmentally friendly and efficient solution for the design and application of metal single-atom materials, and is particularly suitable for energy conversion, environmental governance, catalysis, and biology. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a structural diagram of bis(4,6-difluorophenylpyridine-N,C2)picolinoyliridium used in Example 1 of the method of the present invention.

[0012] Figure 2 is a structural diagram of methyl(triphenylphosphine)gold(I) used in Example 2 of the method described in the present invention.

[0013] Figure 3 1 is a structural diagram of bis(dithiobenzil)nickel used in Example 3 of the method of the present invention.

[0014] Figure 4 1 is a structural diagram of MOF: MIL-88B(Fe) used in Example 4 of the method described in the present invention.

[0015] Figure 5 This is an AC-HAADF-STEM image of an Ir single atom prepared in Example 1 of the method described in the present invention.

[0016] Figure 6 This is an AC-HAADF-STEM image of Au single atoms prepared by Example 2 of the method described in the present invention.

[0017] Figure 7 This is an AC-HAADF-STEM image of Ni single atom prepared by Example 3 of the method described in the present invention.

[0018] Figure 8 This is an AC-HAADF-STEM image of Fe single atoms prepared by Example 4 of the method described in the present invention. DETAILED DESCRIPTION

[0019] Example 1 (Preparation of Ir Single Atom Material):

[0020] 1. Take 10 mmol of bis(4,6-difluorophenylpyridine-N,C2)picolinoyliridium (structure attached) Figure 1) The powder is evenly placed in the electron beam irradiation device;

[0021] 2. In the vacuum chamber (10 -3 Pa) with an electron beam energy of 100 eV and a beam current density of 50 mc / cm 2 Irradiate for 3 minutes.

[0022] 3. The product is a black solid. AC-HAADF-STEM shows that Ir atoms are evenly dispersed (see attached Figure 5 ).

[0023] Example 2 (Preparation of Au Single Atom Material):

[0024] 1. Take 5 mmol of methyl(triphenylphosphine)gold(I) (structure attached) Figure 2 ) are evenly placed in an electron beam irradiation device;

[0025] 2. In an argon atmosphere, set the electron beam energy to 300 eV and the beam current density to 50 mc / cm 2 , irradiation for 1 minute.

[0026] 3. The product is a black solid. AC-HAADF-STEM shows that Au atoms are evenly dispersed (attached Figure 6 ).

[0027] Example 3 (Ni single atom material preparation):

[0028] 1. Take 10 mmol of bis(dithiobenzyl)nickel (structure attached) Figure 3 ) are evenly placed in an electron beam irradiation device;

[0029] 2. In an argon atmosphere, set the electron beam energy to 300 eV and the beam current density to 50 mc / cm 2 , irradiate for 5 minutes.

[0030] 3. The product is a black solid. AC-HAADF-STEM shows that Ni atoms are evenly dispersed (see attached Figure 7 ).

[0031] Example 4 (Fe single atom material preparation):

[0032] 1. Take 5 mmol MOF:MIL-88B(Fe) (structure attached) Figure 4 ) are evenly placed in an electron beam irradiation device. This material is also known as MIL-88B (FE) metal organic framework or TRIS [M-[1,4-phthalic acid (2-)-ΚO1:ΚO'1]]-M3-oxygen triiron;

[0033] 2. In an argon atmosphere, set the electron beam energy to 100 eV and the beam current density to 50 mc / cm2 , irradiation for 3 minutes.

[0034] 3. The product is a black solid. AC-HAADF-STEM shows that Fe atoms are evenly dispersed (see attached Figure 8 ).

[0035] It is worth pointing out that the in-depth mechanism of the present invention still needs further research. We believe that its basic mechanism is that irradiation changes the CH bond of the aromatic ring, causing adjacent aromatic rings to form cross-links to form a large carbon carrier, thereby "precipitating" the metal atom as the central atom to produce a metal single atom.

[0036] Based on the above analysis and the aforementioned embodiments, we can reasonably infer that the present invention can be applied to the heteroatom-containing aromatic metal coordination compounds described in the summary of the invention, and can achieve the purpose of the invention.

Claims

1. A method for preparing metal single-atom materials based on electron beam irradiation, characterized in that: Only an aryl metal coordination compound containing heteroatoms is used as a raw material, and electron beam irradiation is performed under vacuum or inert gas protection; the aryl metal coordination compound containing heteroatoms has a metal atom as a central atom, and the central atom is directly or indirectly connected to at least two benzene rings or heteroatom-substituted benzene-like rings, wherein at least one heteroatom-substituted benzene-like ring is connected; the heteroatom is N, P, O or S.

2. The method for preparing metal single-atom materials based on electron beam irradiation according to claim 1, characterized in that: The heteroatom-containing aromatic metal coordination compound is selected from bis(4,6-difluorophenylpyridine-N,C2)pyridinecarbonyl iridium, methyl(triphenylphosphine)gold(I), bis(dithiobenzil)nickel, MOF:MIL-88B(Fe), tris(2-(4-fluorophenyl)pyridine)iridium, trifluoromethyl(1,10-phenanthroline)copper(I), tris(triphenylphosphine)ruthenium(II)dichloride, bis(triphenylphosphine)cobalt chloride, Fe phthalocyanine, Cu phthalocyanine, Pd phthalocyanine, heme, vitamin B12, 1,2-bis(diphenylphosphine)ethanenickel(II)chloride, tetrakis(triphenyl)phosphine palladium, tetrakis(triphenyl)phosphine ruthenium or hexapyridine iridium.

3. The method for preparing metal single-atom materials based on electron beam irradiation according to claim 1 or 2, characterized in that: The amount of raw materials is 1-100 mmol, the energy of the electron beam is 50 eV-100 keV, and the beam current density is 10-50 mc / cm 2 , irradiation time 1–50 minutes.

4. The metal single atom material obtained by the method according to any one of claims 1 to 3 is used as a catalyst.

Images