A single-atom ruthenium-containing carbon-supported molybdenum carbide flower ball and a preparation method and application thereof
By preparing carbon-supported molybdenum carbide flower spheres and doping them with ruthenium single atoms, the problems of high cost and insufficient catalytic activity of precious metals were solved, achieving efficient and stable hydrogen production through water electrolysis, which has broad application prospects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING NORMAL UNIVERSITY
- Filing Date
- 2023-02-22
- Publication Date
- 2026-06-09
Smart Images
Figure CN116219487B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a carbon-supported molybdenum carbide flower ball containing ruthenium single atoms, its preparation method and application, belonging to the field of electrocatalytic hydrogen evolution catalyst technology. Background Technology
[0002] Currently, the scarcity of traditional chemical fuels and the resulting environmental pollution have led to the increasing importance of hydrogen energy. As a clean secondary energy source, hydrogen energy boasts advantages such as abundant resources and high energy density, and its use can achieve the ideal goal of zero greenhouse gas and pollutant emissions. Among numerous hydrogen production methods, water electrolysis stands out as a promising method due to its simple process, high hydrogen production efficiency, and high product purity. However, the hydrogen evolution reaction in water electrolysis is affected by factors such as high overpotential, limiting its efficiency. Therefore, finding the optimal electrochemical catalyst is crucial for improving the efficiency of the hydrogen evolution reaction.
[0003] Pt-based catalysts are considered the best catalysts for the hydrogen evolution reaction (HER), but their scarcity and high cost limit their potential for large-scale production. Ruthenium-based catalysts, also platinum group catalysts, are significantly cheaper than platinum-based catalysts and exhibit superior catalytic performance compared to many inexpensive transition metal catalysts, making them comparable to platinum-based catalysts. Therefore, developing ruthenium-based catalysts for efficient and stable HER reactions is crucial. To further reduce costs, minimize the amount of precious metals used, and maximize their utilization, designing single-atom-supported catalysts has become a viable option. Excellent catalytic activity and selectivity can be exhibited in single-atom catalysts, and reports indicate that their stability is also superior to that of nanoparticles, demonstrating significant commercial potential. Molybdenum carbide is one of the most studied transition metal carbide systems, benefiting from its low cost, high melting point, good conductivity, and high catalytic activity. However, the catalytic activity of molybdenum carbide as a single substance still needs improvement. Summary of the Invention
[0004] To address the problems of existing technologies, the present invention aims to provide a carbon-supported molybdenum carbide flower-shaped pellet containing ruthenium single atoms, its preparation method, and its applications. The preparation method of the present invention is simple to operate, easy to scale up for production, and the resulting flower-shaped pellets possess advantages such as optimized surface electronic structure, numerous active sites, good conductivity, and high catalytic activity.
[0005] To address the problems of the existing technology, the present invention adopts the following technical solution:
[0006] A carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms comprises carbon-supported molybdenum carbide nanoflowers, with Ru single atoms doped on the molybdenum carbide nanoflowers. It consists of numerous ultrathin nanosheets, on which a large number of ruthenium single atoms are loaded. Strong interactions are formed between the noble metal and the support, which helps to reduce the surface energy of the noble metal, regulate the electronic structure, and increase the exposure of active sites, resulting in better electrochemical performance.
[0007] The preparation method of the above-mentioned carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms includes the following steps:
[0008] Step 1: Ammonium molybdate and dopamine hydrochloride are dispersed in a mixed solution of water and ethanol. A morphology guiding agent is added, and the mixture is stirred and reacted at room temperature for 8 hours. The mixture is then washed with deionized water and freeze-dried. The freeze-dried solid is then heated at high temperature in a reducing atmosphere to obtain carbon-supported molybdenum carbide flower spheres. The morphology guiding agent is ammonia water, and the volume of ammonia water is 0.2-0.6 mL.
[0009] Step 2: Add 50 mg of carbon-supported molybdenum carbide flower balls and the precious metal ruthenium compound to 10 mL of water, heat in a water bath at 50 °C, stir for 12 h, centrifuge and wash, take the precipitate and freeze dry, and place the freeze-dried product in a reducing atmosphere for high-temperature treatment to obtain carbon-supported molybdenum carbide flower balls containing ruthenium single atoms.
[0010] As an improvement, the heating temperature in step 1 is 700-900℃, using a programmed temperature rise, with a holding time of 120-300 min after heating, and a heating rate of 2.5-10℃·min. -1 .
[0011] As an improvement, in step 2, the heating temperature is 300-500℃, a programmed temperature rise is used, the holding time after heating is 30-90 min, and the heating rate is 1-5℃·min. -1 .
[0012] As an improvement, the noble metal ruthenium compound in step 2 is ruthenium trichloride hydrate, ruthenium acetate, ruthenium acetylacetone, or ruthenium carbonyl chloride.
[0013] As an improvement, the mass ratio of ruthenium trichloride hydrate to carbon-supported molybdenum carbide flower heads is 1:(1.7-10).
[0014] The above-mentioned carbon-supported molybdenum carbide flower balls containing ruthenium single atoms are used as electrocatalytic hydrogen evolution catalysts under acidic and alkaline conditions.
[0015] The principle of this invention is as follows: using ammonia as a morphology directing agent, dopamine hydrochloride as a ligand, and ammonium molybdate as a molybdenum source, high-temperature reduction generates carbon-supported molybdenum carbide flower-shaped particles. Then, through a simple impregnation method, ruthenium trichloride hydrate is used as a noble metal source, followed by high-temperature reduction to prepare carbon-supported molybdenum carbide flower-shaped particles containing ruthenium single atoms. This catalyst is a nano-flower-shaped particle with a regular shape, and the resulting catalyst exhibits high electrocatalytic activity and stability.
[0016] Beneficial effects:
[0017] Compared with existing technologies, the present invention provides a carbon-supported molybdenum carbide flower ball containing ruthenium single atoms, its preparation method, and its application, which have the following advantages:
[0018] 1) This invention prepares carbon-supported molybdenum carbide flowerball catalysts containing ruthenium single atoms through a simple and scalable impregnation method;
[0019] 2) The preparation method in this invention is simple and easy to implement, reduces the cost of precious metals, requires simple equipment, and can achieve large-scale production;
[0020] 3) The product obtained by this invention has a nanoflower structure with uniform shape and many active sites. It has excellent electrocatalytic activity and stability in both acidic and alkaline solutions, and is a very promising catalyst for hydrogen evolution in water electrolysis with broad application prospects in the future energy industry. Attached Figure Description
[0021] Figure 1 This is the SEM image of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method in Example 1;
[0022] Figure 2 This is a low-magnification TEM image of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method in Example 1;
[0023] Figure 3 This is a high-magnification HR-TEM image of carbon-supported molybdenum carbide flower spheres containing ruthenium single atoms prepared by the method in Example 1;
[0024] Figure 4 This is an aberration-corrected high-angle annular dark-field-scanning transmission electron image (HAADF-STEM) of a carbon-supported molybdenum carbide flower ball containing ruthenium single atoms prepared by the method of Example 1.
[0025] Figure 5 The XRD pattern of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method in Example 1;
[0026] Figure 6 The Raman spectrum of the carbon-supported molybdenum carbide flower spheres containing ruthenium single atoms prepared by the method in Example 1 is shown.
[0027] Figure 7 The hydrogen evolution performance test spectra of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method of Example 1 and Pt / C are shown in (a) and (b), respectively, as comparison of LSV curves under acidic and alkaline conditions.
[0028] Figure 8 The hydrogen evolution cycle stability test spectra of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method of Example 1 are shown in (a) and (b), respectively, under acidic and alkaline conditions.
[0029] Figure 9 The chronoamperometry spectra of hydrogen evolution of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by the method of Example 1 are shown in (a) and (b), respectively, under acidic and alkaline conditions. Detailed Implementation
[0030] The technical solution of the present invention will be further described in detail below through specific embodiments.
[0031] Example 1
[0032] A method for preparing carbon-supported molybdenum carbide flower-shaped particles containing ruthenium single atoms includes the following steps:
[0033] 1) Preparation of MoC@C flower balls: Ammonium molybdate was dissolved in a mixed solution of water and anhydrous ethanol and stirred for 30 min until fully dissolved. During the stirring process, 0.4 mL of ammonia water was added and stirred for 1 h. Dopamine hydrochloride was added during the stirring process and stirred for 8 h. After centrifugation and freeze-drying, the resulting solid powder was placed in a porcelain boat and heat-treated at 850 °C with a programmed temperature increase of 5 °C / min under a reducing atmosphere and held at this temperature for 180 min. Then it was cooled to obtain MoC@C flower balls.
[0034] 2) Preparation of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms: Ruthenium trichloride hydrate and MoC@C flower balls were dissolved in 10 mL of water at a mass ratio of 1:5. After stirring in a water bath for 12 h, the mixture was centrifuged and freeze-dried. The resulting solid powder was placed in a porcelain boat and heat-treated at 400 °C with a programmed temperature increase of 3 °C / min under a reducing atmosphere. The temperature was maintained at this temperature for 60 min and then cooled to obtain carbon-supported molybdenum carbide flower balls containing ruthenium single atoms.
[0035] Performance Characterization
[0036] The samples prepared in Example 1 were physically characterized using TEM, HRTEM, SEM, XRD, and XPS.
[0037] From SEM ( Figure 1 ), TEM Figure 2 ) and HR-TEM ( Figure 3As can be seen from the spectrum, the ruthenium-containing carbon-supported molybdenum carbide catalyst prepared according to the method described in Example 1 has a nanoflower structure. This structure can provide more active sites, which is beneficial for electrolyte transport and diffusion.
[0038] Results of high-angle annular dark-field image-scanning transmission electron imaging (HAADF-STEM) tests under different backgrounds are as follows: Figure 4 As shown, different elements exhibit varying contrasts due to their different structures, with heavier elements displaying higher brightness. As indicated by the circles in the figure, the noble metal Ru is almost uniformly dispersed at the lattice intersections of the carbon structure and the MoC cluster, confirming that the synthesized sample Ru / MoC@C is a ruthenium single-atom catalyst. Simultaneously, it can be seen that the lattice spacing of MoC is 0.23 nm, corresponding to the (100) crystal plane of the MoC species.
[0039] Figure 5 The XRD pattern of the molybdenum carbide flower spheres supported on carbon containing ruthenium single atoms prepared according to Example 1 shows that the diffraction peaks are completely consistent with the standard card of MoC (JCPDS No. 89-2868) when compared with the standard pattern, proving the successful formation of MoC@C.
[0040] Figure 6 As can be seen from the Raman plot of the carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared according to Example 1, I D / I G =1.02, so the sample has more active sites and good catalytic activity.
[0041] Example 2
[0042] Except for changing the mass ratio of hydrated ruthenium trichloride to MoC@C flower heads to 1:10, the rest is the same as in Example 1.
[0043] Example 3
[0044] Except for changing the mass ratio of hydrated ruthenium trichloride to MoC@C flower heads to 1:2.5, the rest is the same as in Example 1.
[0045] Example 4
[0046] Except for changing the mass ratio of hydrated ruthenium trichloride to MoC@C flower heads to 1:1.7, the rest is the same as in Example 1.
[0047] Example 5
[0048] Except for changing the volume of ammonia water to 0.2 mL, the rest is the same as in Example 1.
[0049] Example 6
[0050] Except for changing the volume of ammonia water to 0.6 mL, the rest is the same as in Example 1.
[0051] Example 7
[0052] Except for changing the temperature ramp in step 1 to 2.5℃ / min, the rest is the same as in Example 1.
[0053] Example 8
[0054] Except for changing the temperature ramp in step 1 to 10℃ / min, the rest is the same as in Example 1.
[0055] Example 9
[0056] Except for step 1, where the temperature is raised to 700°C, the rest is the same as in Example 1.
[0057] Example 10
[0058] Except for step 1, where the temperature is raised to 900°C, the rest is the same as in Example 1.
[0059] Example 11
[0060] Except for changing the heat treatment holding time in step 1 to 120 minutes, the rest is the same as in Example 1.
[0061] Example 12
[0062] Except for changing the heat treatment holding time in step 1 to 300 min, the rest is the same as in Example 1.
[0063] Example 13
[0064] Except for changing the heating rate in step 2 to 1℃ / min, the rest is the same as in Example 1.
[0065] Example 14
[0066] Except for changing the heating rate in step 2 to 5℃ / min, the rest is the same as in Example 1.
[0067] Example 15
[0068] Except for step 2, which involves heating to 300°C, the rest of the procedure is the same as in Example 1.
[0069] Example 16
[0070] Except for step 2, which involves heating to 500°C, the rest of the procedure is the same as in Example 1.
[0071] Example 17
[0072] Except for step 2, where the holding time is changed to 30 minutes after heating, the rest is the same as in Example 1.
[0073] Example 18
[0074] Except for step 2, where the holding time is changed to 90 minutes after heating, the rest is the same as in Example 1.
[0075] Comparative Example 1
[0076] The MoC@C flower balls were prepared using the same method as in the first step of Example 1, except that the second step of impregnation to impregnate ruthenium single atoms was not performed in this example. Specifically, 50 mg of MoC@C flower balls were dissolved in 10 mL of water, stirred in a water bath for 12 h, centrifuged and freeze-dried, and the resulting solid powder was placed in a porcelain boat. Under a reducing atmosphere, the temperature was increased to 400 °C at a programmed rate of 3 °C / min and held at this temperature for 60 min. After cooling, the final product was obtained.
[0077] Comparative Example 2
[0078] A method for preparing carbon-supported molybdenum carbide flower-shaped particles containing ruthenium single atoms includes the following steps:
[0079] 1) Preparation of MoC@C flower balls: Ammonium molybdate was dissolved in a mixed solution of water and anhydrous ethanol and stirred for 30 min until fully dissolved. During the stirring process, 0.4 mL of ammonia water was added and stirred for 1 h. Dopamine hydrochloride was added during the stirring process and stirred for 8 h. After centrifugation and freeze-drying, the resulting solid powder was placed in a porcelain boat and heat-treated at 850 °C at a programmed temperature of 5 °C / min under a reducing atmosphere. The temperature was maintained at this temperature for 180 min and then cooled to obtain the solid powder.
[0080] 2) Preparation of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms: Ruthenium trichloride hydrate and solid powder were dissolved in 10 mL of water at a mass ratio of 1:5. After stirring in a water bath for 12 h, the mixture was centrifuged and freeze-dried. The resulting solid powder was placed in a porcelain boat and heat-treated at 400 °C at a programmed temperature of 3 °C / min under a reducing atmosphere. The temperature was maintained at this temperature for 90 min, and then cooled to obtain the final product.
[0081] Figure 7 The results show the hydrogen evolution performance of carbon-supported molybdenum carbide flower balls containing ruthenium single atoms. The specific steps are as follows:
[0082] 2 mg of catalyst was ultrasonically dispersed in 1 mL of an ethanol-water mixture (water:ethanol volume ratio 3:1) to prepare catalyst ink. Subsequently, 20 μL of the solution was dropped onto the surface of a glassy carbon electrode and dried in an oven at 45 °C. Then, 5 μL of Nafion solution was dropped onto the catalyst-coated glassy carbon electrode. Before HER testing, N2 was bubbled through a 1 M KOH electrolyte for at least 20 min to fill the electrolyte. The linear sweep voltammetry (LSV) assay used for HER testing was then performed in this electrolyte at a scan rate of 5 mV / s. -1 .
[0083] The carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms achieves 10 mA cm⁻¹ under both acidic and alkaline conditions. -2 At these conditions, only 25mV and 11mV overpotentials are required, respectively. Under alkaline conditions, it outperforms commercial Pt / C catalysts, while under acidic conditions, its performance is slightly lower than that of commercial Pt / C catalysts. However, under high current density, its performance under both acidic and alkaline conditions is superior to that of commercial Pt / C catalysts.
[0084] Figure 8 The results show the cycle stability of the carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms. The specific operating steps are as follows:
[0085] All electrochemical tests were performed using a Shanghai Chenhua 760E electrochemical workstation in a three-electrode system. The three-electrode system used a glassy carbon electrode (GCE, d = 3 mm, S = 0.0706 cm). 2 A saturated calomel electrode (SCE) and a carbon rod were used as the working electrode and reference electrode, respectively, while the carbon rod served as the auxiliary electrode during testing. Performance was compared before and after 3000 cyclic voltammetry (CV) cycles.
[0086] The results showed that the catalyst performance did not decrease significantly after 3000 cycles, proving that the catalyst prepared in this invention has good stability in both acidic and alkaline environments.
[0087] Figure 9 These are the chronoamperometry results for a carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms. The specific operating steps are as follows:
[0088] All electrochemical tests were performed using a Shanghai Chenhua 760E electrochemical workstation in a three-electrode system. The three-electrode system used a glassy carbon electrode (GCE, d = 3 mm, S = 0.0706 cm). 2 A saturated calomel electrode (SCE) and a carbon rod were used as the working electrode and reference electrode, respectively, while the carbon rod served as the auxiliary electrode during the test. A chronoamperometry (it) test was performed, and the relationship between current and time was recorded under a constant voltage.
[0089] The results showed that the catalyst performance did not decrease significantly after 25 hours of chronoamperometry testing, demonstrating that the catalyst prepared in this invention has good stability in both acidic and alkaline environments.
[0090] In summary, the carbon-supported molybdenum carbide flower balls containing ruthenium single atoms prepared by this invention have broad application prospects as catalysts for hydrogen evolution in water electrolysis.
Claims
1. A carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms, characterized in that: The catalyst comprises carbon-supported molybdenum carbide nanospheres, wherein the molybdenum carbide nanospheres are doped with Ru single atoms; the preparation method of the carbon-supported molybdenum carbide nanosphere catalyst containing ruthenium single atoms includes the following steps: Step 1, ammonium molybdate and dopamine hydrochloride are dispersed in a mixed solution of water and ethanol, a morphology directing agent is added, the reaction is stirred at room temperature for 8 hours, the solid is washed with deionized water and freeze-dried, and the freeze-dried solid is heated at high temperature in a reducing atmosphere to obtain carbon-supported molybdenum carbide nanospheres, wherein the morphology directing agent is ammonia water, and the volume of ammonia water is 0.2-0.6 mL; Step 2, 50 mg of carbon-supported molybdenum carbide nanospheres and a noble metal ruthenium compound are added to 10 mL of water, the mixture is heated in a water bath at 50 °C and stirred for 12 hours, the solid is centrifuged and washed, the precipitate is freeze-dried, and the freeze-dried product is placed in a reducing atmosphere for high temperature treatment to obtain carbon-supported molybdenum carbide nanospheres containing ruthenium single atoms.
2. A method for preparing a carbon-supported molybdenum carbide flowerball catalyst containing ruthenium single atoms as described in claim 1, characterized in that, Includes the following steps: Step 1: Ammonium molybdate and dopamine hydrochloride are dispersed in a mixed solution of water and ethanol. A morphology guiding agent is added, and the mixture is stirred and reacted at room temperature for 8 hours. The mixture is then washed with deionized water and freeze-dried. The freeze-dried solid is then heated at high temperature in a reducing atmosphere to obtain carbon-supported molybdenum carbide flower spheres. The morphology guiding agent is ammonia water, and the volume of ammonia water is 0.2-0.6 mL. Step 2: Add 50 mg of carbon-supported molybdenum carbide flower balls and the precious metal ruthenium compound to 10 mL of water, heat in a water bath at 50 °C, stir for 12 h, centrifuge and wash, take the precipitate and freeze dry, and place the freeze-dried product in a reducing atmosphere for high-temperature treatment to obtain carbon-supported molybdenum carbide flower balls containing ruthenium single atoms.
3. The method for preparing a carbon-supported molybdenum carbide flowerball catalyst containing ruthenium single atoms according to claim 2, characterized in that: In step 1, the heating temperature is 700-900℃, using a programmed temperature rise method. After heating, the holding time is 120-300 min, and the heating rate is 2.5-10℃·min. -1 .
4. The method for preparing a carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms according to claim 2, characterized in that: In step 2, the heating temperature is 300-500℃, using a programmed temperature rise method. After heating, the holding time is 30-90 minutes, and the heating rate is 1-5℃·min. -1 .
5. The method for preparing a carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms according to claim 2, characterized in that: In step 2, the noble metal ruthenium compound is ruthenium trichloride hydrate, ruthenium acetate, ruthenium acetylacetone, or ruthenium carbonyl chloride.
6. The method for preparing a carbon-supported molybdenum carbide flower-shaped catalyst containing ruthenium single atoms according to claim 5, characterized in that: The mass ratio of ruthenium trichloride hydrate to carbon-supported molybdenum carbide flower heads is 1:1.7-10.
7. The application of the carbon-supported molybdenum carbide flower balls containing ruthenium single atoms as described in claim 1 as an electrocatalytic hydrogen evolution catalyst under acidic or alkaline conditions.