Preparation method of non-noble metal monatomic catalyst material containing organochlorine structure
By constructing non-noble metal single-atom catalyst materials with organochlorine structures, the problem of poor stability of non-noble metal catalysts in acidic oxygen reduction reactions was solved, achieving high activity and low peroxide species yield, which is suitable for electrocatalytic oxygen reduction reactions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-03-24
AI Technical Summary
Existing non-precious metal single-atom catalysts suffer from poor stability due to reactive oxygen attack in acidic oxygen reduction reactions, and traditional methods often reduce catalytic activity when trying to improve stability.
By constructing non-noble metal single-atom catalyst materials containing organochlorine structures, and employing steps such as ZIF-based material synthesis, pyrolysis treatment, and active metal loading, a stable organochlorine structure is formed, thereby improving the stability of the catalyst and maintaining its activity.
It significantly improves the stability and activity of the catalyst in acidic media, reduces the yield of peroxide species, has a small half-wave potential decay, and a low hydrogen peroxide yield, making it suitable for electrocatalytic oxygen reduction reactions.
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Figure CN121715225A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanocatalytic materials technology, specifically relating to a method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure. Background Technology
[0002] Single-atom catalysts possess numerous advantages, including high atom utilization, good dispersion of active sites, and tunable coordination structures. In recent years, they have been applied to various reactions, with the electrocatalytic oxygen reduction reaction being one of the most representative. Fe-based and Co-based single-atom electrocatalysts have been extensively studied for this reaction and are considered the most promising alternatives to noble metal catalysts. However, while non-noble metal catalysts have achieved considerable competitiveness in electrocatalytic activity, they still lag significantly in stability.
[0003] Among the many factors affecting the catalytic stability of acidic ORR reactions, the positive feedback loop of demetallization and support collapse caused by reactive oxygen species attack is one of the core factors affecting the intrinsic activity loss of single-atom catalysts. Therefore, how to improve the structure of single-atom catalysts and reduce the generation of highly reactive peroxide species during the reaction is a very critical issue in the research of single-atom catalysts for oxygen reduction reactions.
[0004] Current research on improving the stability of single-atom catalysts mainly focuses on two aspects: regulating the coordination environment of the active center and introducing a second metal to construct a diatomic synergistic catalyst. However, the cost of improving catalyst stability using traditional methods is often a reduction in the catalyst's intrinsic catalytic activity. Summary of the Invention
[0005] To address the problem of reactive oxygen species attack on single-atom electrocatalysts in acidic oxygen reduction reactions, this invention proposes a method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure. This invention innovatively proposes constructing a structure with non-metallic element chlorine as the core. While ensuring that the active structure of the catalyst itself remains unchanged, the modification of the original inactive structure improves both the stability and activity of the catalyst.
[0006] The technical solution of this invention is as follows:
[0007] A method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure includes the following steps:
[0008] Step (1), Synthesis of ZIF-based material: Zinc nitrate hexahydrate is dissolved in methanol as solution A, with a concentration of 50 g / L-80 g / L. 2-methylimidazole is dissolved in methanol as solution B, with a concentration of 30 g / L-50 g / L. Solution A is added to solution B. After mixing, the mass ratio of zinc nitrate to 2-methylimidazole in the solution is 1:1-1:3. The mixture is stirred thoroughly and ZIF-8 is obtained by separation.
[0009] Step (2), First pyrolysis: The ZIF-8 material obtained in step (1) is mixed with an alkali metal or alkaline earth metal salt of perchloric acid and pyrolyzed in an argon gas flow containing hydrogen at 800-1200℃ for 60min-240min to obtain a carbon support.
[0010] Step (3), active metal loading: The transition metal salt of perchloric acid and the carbon support obtained in step (2) are dispersed in an organic solvent by impregnation. After they are dispersed evenly, they are mixed and stirred for more than 6 hours.
[0011] Step (4), secondary pyrolysis: The impregnated carbon material is mixed with alkali metal or alkaline earth metal salts of perchloric acid and heat-treated at 600-900℃ for 3-5 hours in an argon gas flow containing hydrogen. After natural cooling, a single-atom catalyst with an organochlorine structure is obtained.
[0012] Furthermore, in step (2), the volume percentage of hydrogen in the argon gas stream containing hydrogen is 8%-12%. In step (4), the volume percentage of hydrogen in the argon gas stream containing hydrogen is 10%-20%.
[0013] Furthermore, the alkali metal or alkaline earth metal salt of perchloric acid mentioned in steps (2) and (4) is one or a mixture of two or more of sodium perchlorate, potassium perchlorate, magnesium perchlorate, and calcium perchlorate.
[0014] Furthermore, in step (2), the amount of alkali metal or alkaline earth metal salt of perchloric acid added per 1g of ZIF-8 powder is less than or equal to 8mmol.
[0015] Furthermore, the transition metal salt of perchloric acid in step (3) is one or a mixture of two or more of manganese perchlorate, ferric perchlorate, ferrous perchlorate, cobalt perchlorate, nickel perchlorate, and copper perchlorate.
[0016] Furthermore, in step (3), 0.3 mmol-0.7 mmol of a transition metal salt of perchloric acid is added for every 500 mg of carbon carrier.
[0017] Furthermore, in step (4), the amount of alkali metal or alkaline earth metal salt of perchloric acid added to every 100 mg of impregnated and adsorbed carbon material is less than or equal to 0.8 mmol.
[0018] In the aforementioned organochlorine-structured non-precious metal single-atom catalyst material, the metal loading is 1-3 wt%, and the organochlorine accounts for 0.1%-20% of all chlorine elements.
[0019] The aforementioned organochlorine-structured non-noble metal single-atom catalyst material is applied in electrocatalytic oxygen reduction and proton exchange membrane fuel cells.
[0020] The present invention has the following beneficial effects:
[0021] The rational design and synthesis of organochlorine structures improved the catalytic activity of carbon-supported single-atom catalysts while reducing the yield of peroxide species in the electrocatalytic oxygen reduction reaction under acidic media. Furthermore, it significantly enhanced the intrinsic stability of the catalyst material, enabling the prepared single-atom catalyst to achieve catalytic activity at 0.1 mol·L⁻¹ oxygen saturation. -1 The HClO4 solution exhibits a high half-wave potential of 0.845 V (vs. RHE), while the hydrogen peroxide yield is only 0.1%. After 30,000 cycles of 0.9 V to 0.6 V (vs. RHE), the half-wave potential decays by only 11 mV. Attached Figure Description
[0022] Figure 1 This is a spherical aberration electron microscope image of the catalyst prepared in Example 1 of this invention.
[0023] Figure 2 This is an XPS Cl2p data graph of the catalyst prepared in Example 1 of this invention.
[0024] Figure 3 This is an ORR electrocatalytic performance graph obtained by RDE testing of the catalyst prepared in Example 1 of this invention.
[0025] Figure 4 This is a stability test diagram of the catalyst prepared in Example 1 of the present invention.
[0026] Figure 5 This is a graph showing the hydrogen peroxide yield and electron transfer number of the catalyst prepared in Example 1 of this invention. Detailed Implementation
[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.
[0028] Example 1:
[0029] (1) Dissolve 8g Zn(NO3)2·6H2O and 8g 2-methylimidazole in 100ml and 300mL of methanol solution respectively, and obtain solution A and solution B by ultrasonic oscillation. Quickly pour solution A into solution B to form a white turbid liquid, and react at 30℃ for 24 hours at 800rpm.
[0030] (2) The turbid liquid in step (1) was filtered and washed with 1L of methanol and then naturally dried to obtain ZIF-8 powder material.
[0031] (3) Mix and grind 10g of ZIF-8 powder material with 1.1g of potassium perchlorate thoroughly and transfer it to a tube furnace.
[0032] (4) Calcination at 950°C for 2 hours in a 10% H2 and 90% Ar gas environment to obtain NCH-Cl.
[0033] (5) Disperse 500mg NCH-Cl in 50mL isopropanol and sonicate to obtain turbid liquid A. Dissolve 150mg ferric perchlorate in 50mL isopropanol and pour the dissolved ferric perchlorate solution into turbid liquid A. Stir at 1200rpm for 12h.
[0034] (6) Filter the turbid liquid from step (5) and let it dry naturally.
[0035] (7) Thoroughly mix and grind 100 mg of powder obtained in step (6) with 10 mg of potassium perchlorate, and transfer it to a tube furnace.
[0036] (8) Calcine at 650°C for 5 hours in an environment of 20% H2 and 80% Ar gas, and then naturally cool to room temperature to obtain NCH-organicCl-FeSA-650.
[0037] (9) Aberration-corrected transmission electron microscopy and X-ray photoelectron spectroscopy of NCH-organicCl-FeSA-650 can yield [data / information]. Figure 1 , Figure 2 The results are shown. Figure 1 This indicates that in materials prepared by this method, the active center metal atoms are distributed on the support surface in the form of single atoms. Figure 2 This indicates that in the materials prepared by this method, chlorine exists in both inorganic and organic forms.
[0038] Example 2:
[0039] (1) Dissolve 5g Zn(NO3)2·6H2O and 15g 2-methylimidazole in 100ml and 300mL of methanol solution respectively, and obtain solution A and solution B by ultrasonic oscillation. Quickly pour solution A into solution B to form a white turbid liquid, and react at 30℃ for 24 hours at 800rpm.
[0040] (2) The turbid liquid in step (1) was filtered and washed with 1L of methanol and then naturally dried to obtain ZIF-8 powder material.
[0041] (3) Mix and grind 10g of ZIF-8 powder material with 0.5g of potassium perchlorate thoroughly and transfer it to a tube furnace.
[0042] (4) Calcination at 950°C for 2 hours in an environment of 8% H2 and 92% Ar gas to obtain NCH 0.5 -Cl.
[0043] (5) Add 500mg NCH 0.5 -Cl was dispersed in 50 mL of isopropanol and ultrasonically dispersed to obtain turbid liquid A. Separately, 248 mg of ferric perchlorate was dissolved in 50 mL of isopropanol, and the dissolved ferric perchlorate solution was poured into turbid liquid A and stirred at 1200 rpm for 12 h.
[0044] (6) Filter the turbid liquid from step (5) and let it dry naturally.
[0045] (7) Thoroughly mix and grind 100 mg of powder obtained in step (6) with 10 mg of potassium perchlorate, and transfer it to a tube furnace.
[0046] (8) Calcine at 750°C for 3 hours in an environment of 20% H2 and 80% Ar gas, and then naturally cool to room temperature to obtain NCH. 0.5 -organicCl-FeSA-750.
[0047] Example 3:
[0048] (1) Dissolve 5g Zn(NO3)2·6H2O and 15g 2-methylimidazole in 100ml and 300mL of methanol solution respectively, and obtain solution A and solution B by ultrasonic oscillation. Quickly pour solution A into solution B to form a white turbid liquid, and react at 30℃ for 24 hours at 800rpm.
[0049] (2) The turbid liquid in step (1) was filtered and washed with 1L of methanol and then naturally dried to obtain ZIF-8 powder material.
[0050] (3) Mix and grind 10g of ZIF-8 powder material with 0.1g of potassium perchlorate thoroughly and transfer it to a tube furnace.
[0051] (4) Calcination at 950°C for 2 hours in a 12% H2 and 88% Ar gas environment yields NCH. 0.1 -Cl.
[0052] (5) Add 500mg NCH 0.1 -Cl was dispersed in 50 mL of isopropanol and ultrasonically dispersed to obtain turbid liquid A. Separately, 106 mg of ferric perchlorate was dissolved in 50 mL of isopropanol, and the dissolved ferric perchlorate solution was poured into turbid liquid A and stirred at 1200 rpm for 12 h.
[0053] (6) Filter the turbid liquid from step (5) and let it dry naturally.
[0054] (7) Thoroughly mix and grind 100 mg of powder obtained in step (6) with 10 mg of potassium perchlorate, and transfer it to a tube furnace.
[0055] (8) Calcine at 850°C for 3 hours in a 20% H2 and 80% Ar gas environment, then naturally cool to room temperature to obtain NCH. 0.1 -organicCl-FeSA-850.
[0056] Example 4: Similar to Example 1, except that ferric perchlorate in step (5) is replaced with manganese perchlorate.
[0057] Example 5: Similar to Example 1, except that ferric perchlorate in step (5) is replaced with ferrous perchlorate.
[0058] Example 6: Similar to Example 1, except that ferric perchlorate in step (5) is replaced with cobalt perchlorate.
[0059] Example 7: Similar to Example 1, except that ferric perchlorate in step (5) is replaced with nickel perchlorate.
[0060] Example 8: Similar to Example 1, except that ferric perchlorate in step (5) is replaced with copper perchlorate.
[0061] Example 9: Similar to Example 1, except that potassium perchlorate in steps (3) and (7) is replaced with sodium perchlorate.
[0062] Example 10: Similar to Example 1, except that potassium perchlorate in steps (3) and (7) is replaced with magnesium perchlorate.
[0063] Example 11: Similar to Example 1, except that potassium perchlorate in steps (3) and (7) is replaced with calcium perchlorate.
[0064] Electrocatalytic testing:
[0065] The NCH-organicCl-FeSA prepared in Example 1 was subjected to electrocatalytic ORR testing.
[0066] In this work, all tests were performed using a standard three-electrode system with a 0.1 mol·L⁻¹ electrolyte. -1 The HClO4 solution was used, with a mercury-mercurous sulfate electrode as the reference electrode and a graphite rod electrode as the counter electrode. RDE testing was performed using a glassy carbon electrode (GC, 0.19625 cm⁻¹). 2 ) was used as the working electrode, and the RRDE test used a glassy carbon disk (GC, 0.2475 cm) 2 - Platinum ring (Pt, 0.1866 cm) 2 The electrode was used as the working electrode. A Zahner Zennium electrochemical workstation was used for RDE testing, and a Chenhua CHI750e electrochemical workstation was used for RRDE testing. The catalyst loading on the working electrode surface was 0.6 mg / cm³ during testing. -2 By using the transformation equation E RHE =E (Hg-Hg2SO4) +0.656+0.0592pH, the potential in this work is called the reversible hydrogen electrode (RHE) potential.
[0067] In this work, all electrochemical tests were performed at 1600 rpm and 10 mV / s. -1 The potentials were obtained at a scan rate of 1.1V–0.1V (vs. RHE) applied to the glassy carbon electrodes with catalysts supported on the RDE and RRDE, and a constant potential of 1.2V (vs. RHE) applied to the platinum rings of the RRDE. All electrode potential data were compensated for with 90% IR potential.
[0068] The results showed that NCH-organicCl-FeSA in Example 1 had good ORR activity, such as Figure 3 As shown, NCH-organicCl-FeSA at 0.1 mol·L⁻¹ -1 The HClO4 solution exhibited a high half-wave potential of 0.845 V (vs. RHE), while Figure 4 This indicates that it still maintains good activity after 30,000 cycles in acidic media, with a half-wave potential decay of only 11 mV. Figure 5 This indicates that the material has a low hydrogen peroxide yield and good 4-electron pathway selectivity. In addition, the data of the samples prepared in Examples 9, 10, and 11 are very close to those of the samples prepared in Example 1.
[0069] The samples prepared in Examples 2 and 3 were tested under the same conditions, and their half-wave potentials were 0.823V (vs. RHE) and 0.817V (vs. RHE), respectively. Their activity is still among the top in iron-based single-atom ORR catalysts. After 10,000 cycles, their half-wave potentials decreased by 17mV and 15mV, respectively, showing good stability.
[0070] The sample prepared in Example 5 was tested under the same conditions. Its half-wave potential was 0.831V (vs. RHE), which showed good activity. After 10,000 cycles, its half-wave potential decayed to 21mV.
[0071] The sample prepared in Example 6 was tested under the same conditions. Its half-wave potential was 0.808V (vs. RHE). After 10,000 cycles, its half-wave potential decreased by 33mV, and its hydrogen peroxide yield was lower than that of similar catalysts.
[0072] The samples prepared in Examples 4, 7, and 8 showed slightly lower activity compared to iron-based single-atom catalysts, but were still among the top in their class.
[0073] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.
Claims
1. A method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure, characterized in that, Includes the following steps: Step (1), Synthesis of ZIF-based material: Zinc nitrate hexahydrate is dissolved in methanol as solution A, with a concentration of 50 g / L-80 g / L. 2-methylimidazole is dissolved in methanol as solution B, with a concentration of 30 g / L-50 g / L. Solution A is added to solution B. After mixing, the mass ratio of zinc nitrate to 2-methylimidazole in the solution is 1:1-1:
3. The mixture is stirred thoroughly and ZIF-8 is obtained by separation. Step (2), First pyrolysis: The ZIF-8 material obtained in step (1) is mixed with an alkali metal or alkaline earth metal salt of perchloric acid and pyrolyzed in an argon gas flow containing hydrogen at 800-1200℃ for 60min-240min to obtain a carbon support. Step (3), active metal loading: The transition metal salt of perchloric acid and the carbon support obtained in step (2) are dispersed in an organic solvent by impregnation. After they are dispersed evenly, they are mixed and stirred for more than 6 hours. Step (4), secondary pyrolysis: The impregnated carbon material is mixed with alkali metal or alkaline earth metal salts of perchloric acid and heat-treated at 600-900℃ for 3-5 hours in an argon gas flow containing hydrogen. After natural cooling, a single-atom catalyst with an organochlorine structure is obtained.
2. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, The volume percentage of hydrogen in the argon gas stream containing hydrogen in step (2) is 8%-12%; the volume percentage of hydrogen in the argon gas stream containing hydrogen in step (4) is 10%-20%.
3. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, The alkali metal or alkaline earth metal salt of perchloric acid mentioned in steps (2) and (4) is one or more of sodium perchlorate, potassium perchlorate, magnesium perchlorate, and calcium perchlorate.
4. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, In step (2), the amount of alkali metal or alkaline earth metal salt of perchloric acid added per 1g of ZIF-8 powder is less than or equal to 8 mmol.
5. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, The transition metal salt of perchloric acid mentioned in step (3) is one or a mixture of two or more of manganese perchlorate, ferric perchlorate, ferrous perchlorate, cobalt perchlorate, nickel perchlorate, and copper perchlorate.
6. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, In step (3), 0.3 mmol-0.7 mmol of transition metal salt of perchloric acid is added for every 500 mg of carbon carrier.
7. The method for preparing a non-noble metal single-atom catalyst material containing an organochlorine structure according to claim 1, characterized in that, In step (4), the amount of alkali metal or alkaline earth metal salt of perchloric acid added to every 100 mg of impregnated and adsorbed carbon material is less than or equal to 0.8 mmol.
8. The organochlorine-structured non-noble metal single-atom catalyst material prepared by the preparation method according to any one of claims 1-7 is characterized in that, The metal loading is 1-3 wt%, and organic chlorine accounts for 0.1%-20% of all chlorine elements.
9. The organochlorine structured non-noble metal single-atom catalyst material prepared by the preparation method according to any one of claims 1-7 is applied in electrocatalytic oxygen reduction and proton exchange membrane fuel cells.