A supported diatom catalyst with adjustable spacing and its preparation method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA UNIVERSITY
- Filing Date
- 2025-03-10
- Publication Date
- 2026-06-02
Smart Images
Figure CN122124831A_ABST
Abstract
Description
Technical Field
[0001] This application relates to a supported diatomic catalyst with adjustable spacing and its preparation method, belonging to the field of catalyst preparation technology. Background Technology
[0002] Diatom catalysts (DACs) have attracted widespread attention in the field of catalysis due to their high atom utilization and synergistic catalytic effect between two atomic sites. The distance between atoms plays a crucial role in diatomic synergistic catalysis, and its catalytic performance varies significantly with changes in the distance between adjacent atoms. Therefore, precisely controlling the distance between diatoms is key to optimizing catalytic performance. Current research on diatomic catalysts focuses on developing novel preparation methods, accurately identifying metal positions and atom pairs, and revealing the structure-activity relationship between diatomic configuration and reaction performance. The control of the distance between the two atoms in diatomic catalysts is still in its early stages, with few published reports.
[0003] Professor Lu's team precisely prepared Pt1Ni1 diatomic and Pt1+Ni1 bis-monoatomic catalysts on g-C3N4 support using atomic layer deposition (ALD) technology, taking advantage of the steric hindrance effect between metal-organic precursors during the ALD process [Angew. Chem. Int. Ed. 2022, 61, e202211919]. The interatomic spacing of the Pt1+Ni1 bis-monoatomic catalysts is shown in the figure. Much larger than Pt1Ni1 diatomic Adjustable interatomic spacing was achieved. The Pt1Ni1 diatomic catalyst exhibited optimal performance, approximately 13 times and 2 times that of the Pt1 single-atom and Pt1+Ni1 dual-single-atom catalysts, respectively. Mechanistic studies revealed significant electron transfer in the Pt1Ni1 diatomic structure, which was absent in the Pt1+Ni1 dual-single-atom structure. However, the aforementioned method contained unpaired dual-single atoms, failing to achieve precise control over the interatomic spacing. Researcher Wang's team used three different impregnation schemes to prepare NiFe-isote diatomic catalysts, NiFe-N bridge diatomic catalysts, and NiFe-bonding diatomic catalysts, respectively, achieving controllable adjustment of the interatomic spacing [Angew. Chem. Int. Ed. 2022, 61, e202211919]. (The text then abruptly shifts to a discussion of NiFe-isote diatomic catalysts and their interatomic spacing, which seems unrelated to the previous paragraphs.) ) or NiFe-bonding diatomic catalyst (atomic spacing) Compared to NiFe-N bridge diatomic catalysts (atomic spacing) With suitable interatomic distances and electronic properties, the NiFe-N bridge diatomic catalyst can nearly double the electroreduction performance of CO2. A series of characterization and theoretical calculations show that Ni transfers more electrons to Fe in the NiFe-N bridge diatomic catalyst, optimizing the electron distribution at the Fe center, resulting in suitable adsorption strength for the *COOH intermediate, and promoting *CO desorption, thereby improving the catalyst's activity and selectivity. However, this method utilizes the porosity of ZIF-8 to prepare diatomic catalysts through co-impregnation, which presents the challenge of accurately distinguishing between target diatomic pairs and densely packed atoms. Precise quantification and statistical analysis of the interatomic distance at the atomic scale requires a combination of more precise characterization techniques. Currently, there is a lack of simple and universal methods in the field of diatomic catalyst synthesis to precisely controllably adjust the interatomic distance between paired diatoms in diatomic catalysts. Summary of the Invention
[0004] To address the problem of precisely controlling the interatomic distance in existing diatomic catalyst technologies, this application proposes a preparation technique for a supported diatomic catalyst with adjustable spacing. This technique utilizes a diamine compound with two amino functional groups as a diatomic structure directing agent and stabilizer. By controlling the chain length of the diamine compound, the spacing between the two strongly interacting atoms can be precisely controlled. The preparation method is simple, independent of metal precursors and instruments, and enables large-scale preparation of supported diatomic catalysts with adjustable spacing.
[0005] The technical solution adopted in this application is as follows:
[0006] According to a first aspect of this application, a supported diatomic catalyst with adjustable spacing is provided, comprising a g-C3N4 support and platinum atoms;
[0007] The platinum atoms are distributed in pairs on the g-C3N4 support.
[0008] According to a second aspect of this application, a method for preparing the above-mentioned adjustable-spacing supported diatomic catalyst is provided, comprising the following steps:
[0009] S1. Obtain g-C3N4 powder;
[0010] S2. The mixture containing platinum ions, diamine compounds, and the g-C3N4 powder is continuously stirred to obtain a raw material liquid;
[0011] S3. Remove the solvent from the raw material liquid and dry it to obtain an intermediate product. Calcine the intermediate product to obtain the supported diatomic catalyst with adjustable spacing.
[0012] The diamine compound used in step S2 of this application acts as a diatomic structure directing agent and stabilizer. By utilizing two amino functional groups, platinum atoms are arranged in regular pairs, and the distance between the two atoms can be precisely controlled.
[0013] Optionally, in step S2, the hybrid configuration process includes:
[0014] An aqueous solution containing platinum ions is added to water, stirred until homogeneous, and then an aqueous solution of a diamine compound and g-C3N4 powder are added sequentially to obtain the mixture.
[0015] Optionally, the concentration of platinum ions in the aqueous solution containing platinum ions is 0.05M to 0.25M.
[0016] Optionally, the volume ratio of the aqueous solution containing platinum ions to the water is 100 μL to 200 μL: 50 mL.
[0017] Optionally, the aqueous solution containing platinum ions is selected from an aqueous solution of chloroplatinic acid.
[0018] Optionally, the concentration of the diamine compound in the aqueous solution is 0.05M to 0.25M.
[0019] Optionally, the volume ratio of the diamine compound aqueous solution to the water is 50 μL to 100 μL: 50 mL.
[0020] Optionally, the diamine compound is selected from at least one of 1,6-hexanediamine (HA) and ethylenediamine (EA).
[0021] Optionally, the solid-liquid ratio of the g-C3N4 powder to the aqueous solution containing platinum ions is 400 mg: 100 μL to 200 μL.
[0022] Optionally, in step S2, the conditions for continuous stirring include a stirring time of 18 to 36 hours.
[0023] Optionally, in step S3, the drying temperature is from 60°C to 80°C.
[0024] Optionally, the solvent removal is performed by heating, and the heating temperature is 60°C to 80°C.
[0025] Optionally, the calcination conditions include: calcination in an inactive atmosphere, a heating rate of 4–6 °C / min, a calcination temperature of 200 °C–400 °C, and a calcination time of 2–3 h.
[0026] Optionally, in step S1, the g-C3N4 powder is obtained by calcining urea.
[0027] Optionally, the conditions for calcining urea include: a heating rate of 4-6°C / min, a calcination temperature of 400°C-600°C, and a calcination time of 3-5 hours.
[0028] The beneficial effects of this application include:
[0029] (1) This application is the first to propose the use of diamine compounds with two amino functional groups for precise control of the interatomic distance in a diatomic catalyst.
[0030] (2) The interatomic spacing between paired atoms in the diamine catalyst provided in this application can be precisely and controllably adjusted. The amino groups at both ends of the diamine compound pair the two diatoms through complexation, and during the thermal decomposition process, the movement of the two atoms is spatially restricted, guiding them to form a diatomic configuration on the g-C3N4 substrate. By controlling the chain length of the diamine compound, the interatomic spacing can be precisely controlled.
[0031] (3) The positions of metal atoms and atom pairs in the diatomic catalyst provided in this application can be easily and accurately identified. The interatomic spacing in the diatomic catalyst is statistically analyzed according to the EMARS methodology [J.Am.Chem.Soc.2021,143(37),15243-15249] to achieve accurate quantification of the interatomic spacing.
[0032] (4) The preparation method provided in this application is simple, does not depend on metal precursors and special instruments, has mild reaction conditions, and can realize the large-scale preparation of diatomic catalysts. Attached Figure Description
[0033] Figure 1 This is an aberration-corrected high-angle annular dark-field scanning transmission microscope image of the Pt2 / C3N4-HA diatomic catalyst in Example 1.
[0034] Figure 2 This is an aberration-corrected high-angle annular dark-field scanning transmission microscope image of the Pt2 / C3N4-EA diatomic catalyst in Example 2.
[0035] Figure 3 Aberration-corrected high-angle annular dark-field scanning transmission microscope image of the Pt2 / C3N4-none atomic catalyst in the comparative example;
[0036] Figure 4 This is a schematic diagram of the interatomic spacing distribution of the atomic catalysts described in Examples 1-2 and Comparative Example 1. Detailed Implementation
[0037] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0038] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0039] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.
[0040] Example 1
[0041] Step 1: Place urea in an alumina crucible and calcine it in a muffle furnace at 550°C for 4 hours with a heating rate of 5°C / min to obtain a light yellow powder g-C3N4.
[0042] Step 2: Add 160 μL of 0.1 M H₂PtCl₆·6H₂O aqueous solution to 50 mL of water and stir continuously to obtain a homogeneous solution. Then add 85 μL of 0.15 M 1,6-hexanediamine aqueous solution to the above solution, mix well, and then add 400 mg g-C₃N₄ to the above solution and stir continuously for 24 h.
[0043] Step 3: Heat at 80℃ to remove the aqueous solvent, dry at 60℃ overnight, and calcine the obtained product in N2 at 350℃ for 2 hours to obtain a supported diatomic catalyst with adjustable spacing. The final product is denoted as Pt2 / C3N4-HA diatomic catalyst.
[0044] Example 2
[0045] Step 1: Place urea in an alumina crucible and calcine it in a muffle furnace at 550°C for 4 hours with a heating rate of 5°C / min to obtain a light yellow powder g-C3N4.
[0046] Step 2: Add 160 μL of 0.1 M H₂PtCl₆·6H₂O aqueous solution to 50 mL of water and stir continuously to obtain a homogeneous solution. Then add 85 μL of 0.15 M ethylenediamine aqueous solution to the above solution, mix well, and then add 400 mg of C₃N₄ to the above solution and stir continuously for 24 h.
[0047] Step 3: Heat at 80℃ to remove the aqueous solvent, dry at 60℃ overnight, and calcine the obtained product in N2 at 350℃ for 2 hours to obtain a supported diatomic catalyst with adjustable spacing. The final product is denoted as Pt2 / C3N4-EA diatomic catalyst.
[0048] Comparative Example 1
[0049] Step 1: Place urea in an alumina crucible and calcine it in a muffle furnace at 550°C for 4 hours with a heating rate of 5°C / min to obtain a light yellow powder g-C3N4.
[0050] Step 2: Add 160 μL of 0.1 M H₂PtCl₆·6H₂O aqueous solution to 50 mL of water and stir continuously to obtain a homogeneous solution. Then add 400 mg g-C₃N₄ to the above solution and stir continuously for 24 h.
[0051] Step 3: Heat at 80℃ to remove the aqueous solvent, dry at 60℃ overnight, and calcine the obtained product in N2 at 300℃ for 2 hours to obtain a supported diatomic catalyst with adjustable spacing. The final product is denoted as Pt2 / C3N4-none atomic catalyst.
[0052] Test case
[0053] The microstructure of the diatomic catalysts prepared in Examples 1-2 and Comparative Example 1 of this application was observed, and the following experimental results were obtained:
[0054] (1) The Pt2 / C3N4-HA diatomic catalyst prepared in Example 1 of this application was observed and photographed using a spherical aberration-corrected high-angle annular dark-field scanning transmission microscope, thereby obtaining the following results: Figure 1 The electron microscope image shown. (By...) Figure 1 It can be clearly seen that in the entire region of the Pt2 / C3N4-HA diatomic catalyst, atoms are arranged in regular pairs, with only a very small number of atoms randomly dispersed as single atoms, and no particulate matter exists.
[0055] (2) The Pt2 / C3N4-EA diatomic catalyst prepared in Example 2 of this application was observed and photographed using a spherical aberration-corrected high-angle annular dark-field scanning transmission microscope, thereby obtaining the following results: Figure 1 The electron microscope image shown. (By...) Figure 1 It can be clearly seen that in the entire region of the Pt2 / C3N4-EA diatomic catalyst, atoms are arranged in regular pairs, with only a very small number of atoms randomly dispersed as single atoms, and no particulate matter exists.
[0056] (3) The Pt2 / C3N4-none atomic catalyst prepared in Comparative Example 1 of this application was observed and photographed using a spherical aberration-corrected high-angle annular dark-field scanning transmission microscope, thereby obtaining the following results: Figure 1 The electron microscope image shown. (By...) Figure 1 It can be clearly seen that in the entire region of the Pt2 / C3N4-none atomic catalyst, there are a large number of atoms concentrated and randomly dispersed as single atoms, with no obvious and easily distinguishable atom pairs and no particulate matter present.
[0057] (4) The interatomic spacing in the diatomic catalysts prepared in Examples 1-2 and Comparative Example 1 was statistically analyzed using the EMARS methodology [J.Am.Chem.Soc.2021,143(37),15243-15249], resulting in the following... Figure 4 The diagram shows the interatomic spacing distribution. Analysis of over 2400 atoms in the Pt2 / C3N4-HA diatomic catalyst revealed a maximum interatomic spacing of 0.49 nm. Analysis of over 2300 atoms in the Pt2 / C3N4-EA diatomic catalyst revealed a maximum interatomic spacing of 0.22 nm. Analysis of over 1950 atoms in the Pt2 / C3N4-none diatomic catalyst revealed a maximum interatomic spacing of 0.29 nm. Figure 4 It can be seen that the addition of diamine compounds with two amino functional groups can effectively regulate the interatomic distance.
[0058] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A supported diatom catalyst with adjustable spacing, characterized in that, Includes g-C3N4 support and platinum atoms; The platinum atoms are distributed in pairs on the g-C3N4 support.
2. The method for preparing the adjustable-spacing supported diatom catalyst according to claim 1, characterized in that, Includes the following steps: S1. Obtain g-C3N4 powder; S2. The mixture containing platinum ions, diamine compounds, and the g-C3N4 powder is continuously stirred to obtain a raw material liquid; S3. Remove the solvent from the raw material liquid and dry it to obtain an intermediate product. Calcine the intermediate product to obtain the supported diatomic catalyst with adjustable spacing.
3. The preparation method according to claim 1, characterized in that, In step S2, the hybrid configuration process includes: An aqueous solution containing platinum ions is added to water, stirred until homogeneous, and then an aqueous solution of a diamine compound and g-C3N4 powder are added sequentially to obtain the mixture.
4. The preparation method according to claim 3, characterized in that, The concentration of platinum ions in the aqueous solution containing platinum ions is 0.05M to 0.25M; Preferably, the volume ratio of the aqueous solution containing platinum ions to the water is 100 μL to 200 μL: 50 mL; Preferably, the aqueous solution containing platinum ions is selected from an aqueous solution of chloroplatinic acid.
5. The preparation method according to claim 3, characterized in that, The concentration of the diamine compound in the aqueous solution is 0.05 M to 0.25 M; Preferably, the volume ratio of the diamine compound aqueous solution to the water is 50 μL to 100 μL: 50 mL; Preferably, the diamine compound is selected from at least one of 1,6-hexanediamine and ethylenediamine.
6. The preparation method according to claim 3, characterized in that, The solid-liquid ratio of the g-C3N4 powder to the aqueous solution containing platinum ions is 400 mg: 100 μL to 200 μL.
7. The preparation method according to claim 1, characterized in that, In step S2, the conditions for continuous stirring include a stirring time of 18 to 36 hours.
8. The preparation method according to claim 1, characterized in that, In step S3, the drying temperature is from 60°C to 80°C; Preferably, the solvent removal is performed by heating, and the heating temperature is 60°C to 80°C; Preferably, the calcination conditions include: calcination in an inactive atmosphere, a heating rate of 4-6°C / min, a calcination temperature of 200°C-400°C, and a calcination time of 2-3 hours.
9. The preparation method according to claim 1, characterized in that, In step S1, the g-C3N4 powder is obtained by calcining urea.
10. The preparation method according to claim 9, characterized in that, The conditions for calcining urea include: a heating rate of 4-6℃ / min, a calcination temperature of 400℃-600℃, and a calcination time of 3-5h.