A molybdenum-rhodium co-doped ruthenium oxide nano-catalyst, a preparation method and application thereof
By synthesizing molybdenum-rhodium co-doped ruthenium oxide nanocatalysts in a one-step process, the problems of slow kinetics and high catalyst cost in the anodic oxygen evolution reaction during water electrolysis for hydrogen production were solved, achieving efficient and stable electrocatalytic oxygen evolution performance and a simplified preparation process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAQIAO UNIVERSITY
- Filing Date
- 2024-02-06
- Publication Date
- 2026-06-05
AI Technical Summary
In existing water electrolysis hydrogen production technologies, the kinetics of the anodic oxygen evolution reaction are slow and the catalyst cost is high. Existing synthesis methods are complex, pollute the environment, and have low yields.
A one-step method was used to synthesize molybdenum-rhodium co-doped ruthenium oxide nanocatalysts. By controlling the ratio of precursor salts and reaction conditions, ruthenium-based electrocatalysts with uniform morphology were prepared for electrocatalytic oxygen evolution reaction.
It achieves efficient and stable electrocatalytic oxygen evolution performance, simplifies the preparation process, improves the yield, and avoids environmental pollution.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalytic material preparation technology, specifically relating to a molybdenum-rhodium co-doped ruthenium oxide nanocatalyst, its preparation method, and its application. Background Technology
[0002] Hydrogen energy, with its cleanliness and high efficiency, has become a more suitable energy source for sustainable development compared to traditional energy sources. In industrial hydrogen production methods, water electrolysis technology offers advantages such as high conversion efficiency, simple equipment, and the generation of hydrogen and oxygen at the cathode and anode respectively, eliminating the need for subsequent separation and ensuring high purity. Furthermore, the electricity required for water electrolysis can be obtained through the conversion of renewable resources such as wind, hydro, and solar energy, achieving sustainable energy use. However, slow reaction kinetics and high catalyst costs are key issues hindering its commercialization; therefore, developing efficient, stable, and economical electrocatalysts is crucial. The oxygen evolution reaction at the anode involves a four-electron-proton transfer process, leading to even slower kinetics, thus placing higher demands on the design of the anode catalyst.
[0003] Currently, there are reports in the literature, for example, that the Peng Shengjie research group (Y. Hao, S. Hung, W. Zeng, Y. Wang, C. Zhang, C. Kuo, L. Wang, S. Zhao, Y. Zhang, H. Chen, and S. Peng, J. Am. Chem. Soc., 2023, 145, 23659-23669) anchored ruthenium single atoms on defect-rich cobalt tetroxide and precisely controlled the anchor sites to improve the release of acidic oxygen. The fine structural design can transform the reaction mechanism from the lattice oxygen mechanism (LOM) to the optimized adsorbate evolution mechanism (AEM). The Feng Ligang research group (L. Hou, Z. Li, H. Jang, Y. Wang, X. Cui, X. Gu, M. Kim, L. Feng, S. Liu, and X. Liu, Adv. Energy Mater., 2023, 2300177) found that adding Zn atoms to RuO2 can optimize its electronic structure and distort its local structure, thereby improving its activity and stability in water splitting. The Sun Xiaoming research group (H. Liu, Z. Zhang, J. Fang, M. Li, M. Sendeku, X. Wang, H. Wu, Y. Li, J. Ge, Z. Zhuang, D. Zhou, Y. Kuang, X. Sun, Joule., 2023, 7, 558-573) used a sol-gel method to controllably add a high-valence transition metal, niobium, to ruthenium oxide to avoid over-oxidation of ruthenium, thereby improving oxygen evolution performance and stability at high current densities. However, the above experiments have problems such as complex synthesis methods, environmental pollution caused by the introduction of organic substances such as surfactants during the synthesis process, and low yield.
[0004] Therefore, developing a simple, efficient, controllable, high-performance, and high-yield green chemical method for producing hydrogen from water electrolysis is of great significance for advancing the process. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a molybdenum-rhodium co-doped ruthenium oxide nanocatalyst, its preparation method and application.
[0006] To achieve the above objectives, one of the technical solutions of the present invention is: a method for preparing molybdenum-rhodium co-doped ruthenium oxide nanocatalysts, specifically including the following steps:
[0007] (1) Disperse ruthenium precursor salt, molybdenum chloride and rhodium chloride evenly with an organic solvent by ultrasonication, and then evaporate the organic solvent to obtain a uniformly mixed precursor salt powder.
[0008] (2) Preheat the nitrate at 350-410℃ for 5-15 minutes to obtain molten nitrate;
[0009] (3) Add the precursor salt powder obtained in step (1) to the molten nitrate obtained in step (2), react at 350-410℃ for 5-15 min, cool naturally to room temperature, and wash to obtain molybdenum-rhodium co-doped ruthenium oxide nanoparticles, which are molybdenum-rhodium co-doped ruthenium oxide nanocatalysts.
[0010] In a preferred embodiment of the present invention, the organic solvent in step (1) is one of ethanol, methanol, and acetone.
[0011] In a preferred embodiment of the present invention, the ruthenium precursor salt in step (1) is ruthenium chloride.
[0012] In a preferred embodiment of the present invention, the molar ratio of ruthenium precursor salt, molybdenum chloride, and rhodium chloride in step (1) is 10:(0-1):(0-1), and the amount of organic solvent added is 25-50 mL / 100 mg ruthenium precursor salt.
[0013] In a preferred embodiment of the present invention, the nitrate in step (2) is one of sodium nitrate and potassium nitrate.
[0014] In a preferred embodiment of the present invention, the mass ratio of precursor salt to molten nitrate in step (3) is (30-80):(5000-10000).
[0015] In a preferred embodiment of the present invention, the washing in step (3) is performed alternately with ultrapure water and ethanol.
[0016] To achieve the above objectives, the second technical solution of the present invention is: a molybdenum-rhodium co-doped ruthenium oxide nanocatalyst prepared by the above preparation method.
[0017] In a preferred embodiment of the present invention, the molar ratio of Ru:Mo:Rh in the molybdenum-rhodium co-doped ruthenium oxide nanocatalyst is (80-98):(1-10):(1-10), preferably 10:1:1.
[0018] To achieve the above objectives, the third technical solution of the present invention is: the application of a molybdenum-rhodium co-doped ruthenium oxide nanocatalyst as an electrocatalyst in the electrocatalytic oxygen evolution of water electrolysis.
[0019] Unless otherwise specified, the equipment, reagents, processes, parameters, etc. involved in this invention are all conventional equipment, reagents, processes, parameters, etc., and no further examples will be provided.
[0020] All ranges listed in this invention include all point values within that range.
[0021] In this invention, "room temperature" refers to the normal ambient temperature, which can be 10-30℃.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. This invention synthesizes molybdenum-rhodium co-doped ruthenium oxide nanocatalysts in one step, and the proportion of different metal oxides in the catalyst can be controlled by controlling the amount of precursor salt added, thereby preparing ruthenium-based electrocatalysts with controllable ruthenium content and uniform morphology, which can be used for electrocatalytic oxygen evolution reaction.
[0024] 2. The preparation method and experimental operation of this invention are simple, efficient, have high yield, and are green and pollution-free;
[0025] 3. The molybdenum-rhodium co-doped ruthenium oxide nanocatalyst prepared in this invention has superior catalytic activity and catalytic stability for electrocatalytic oxygen evolution. Attached Figure Description
[0026] Figure 1 The images shown are transmission electron microscope (TEM) images of the nanoparticles prepared in Example 1 and Comparative Examples 1, 2 and 3 of this invention. a is Example 1, b is Comparative Example 1, c is Comparative Example 2 and d is Comparative Example 3.
[0027] Figure 2 The image shows the XRD pattern of the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in Example 1 of this invention.
[0028] Figure 3 This is a comparison diagram of the electrocatalytic oxygen evolution activity in water electrolysis between the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in Example 1 of this invention and a commercial ruthenium oxide catalyst (C-RuO2).
[0029] Figure 4 This is a chronopotential curve of oxygen evolution through water electrolysis between the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in Example 1 of this invention and a commercial ruthenium oxide catalyst (C-RuO2). Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. However, the scope of protection of this invention is not limited to these embodiments. The same reference numerals throughout the text always represent the same elements, and similar reference numerals represent similar elements.
[0031] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", "vertical", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the perspective view in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0032] Example 1
[0033] A molybdenum-rhodium co-doped ruthenium oxide nanocatalyst was prepared by the following method:
[0034] In a 50 mL beaker, 40 mg of ruthenium chloride, 5.3 mg of molybdenum chloride, and 4 mg of rhodium chloride were added. The ruthenium chloride, molybdenum chloride, and rhodium chloride were then dissolved in 10 mL of ethanol. After ultrasonic dispersion at room temperature, the ethanol was evaporated in an oil bath at 80 °C for 3 hours to obtain a uniformly mixed precursor salt powder. 5 g of sodium nitrate was weighed and added to a 30 mL crucible. The crucible was heated in a muffle furnace at 380 °C for 10 minutes to obtain molten sodium nitrate. The uniformly mixed precursor salt was added to the molten sodium nitrate, and the reaction was carried out at 380 °C for 10 minutes. After natural cooling to room temperature, the mixture was thoroughly washed with alternating ultrapure water and ethanol to obtain molybdenum-rhodium co-doped ruthenium oxide nanoparticles, i.e., molybdenum-rhodium co-doped ruthenium oxide nanocatalysts.
[0035] The morphology, composition, and microstructure of the prepared molybdenum-rhodium co-doped ruthenium oxide nanoparticles were systematically studied using modern nanoanalysis techniques such as TEM and XRD. The results are as follows: Figure 1 (a) and Figure 2 .from Figure 1 (a) Figure 2 It can be seen that the molybdenum-rhodium co-doped ruthenium oxide nanocatalyst prepared in Example 1 has a nanoparticle structure; the molybdenum-rhodium co-doped ruthenium oxide nanoparticles belong to the tetragonal crystal system.
[0036] The molybdenum-rhodium co-doped ruthenium oxide nanoparticle catalyst synthesized in this embodiment was used to investigate the electrocatalytic water splitting oxygen evolution reaction. Figure 3 This is a comparison chart showing the catalytic activity of molybdenum-rhodium co-doped ruthenium oxide nanoparticles and commercial ruthenium oxide catalysts in the electrocatalytic oxygen evolution process. Figure 3 It can be seen that the activity of the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in this embodiment is significantly improved. Figure 4 This is a chronopotential curve of electrocatalytic oxygen evolution in water electrolysis using molybdenum-rhodium co-doped ruthenium oxide nanoparticles and a commercial ruthenium oxide catalyst. Figure 4 It can be seen that the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in this embodiment have strong catalytic durability.
[0037] Example 2
[0038] A molybdenum-rhodium co-doped ruthenium oxide nanocatalyst was prepared by the following method:
[0039] In a 50 mL beaker, 40 mg of ruthenium chloride, 2.65 mg of molybdenum chloride, and 2 mg of rhodium chloride were added. The ruthenium chloride, molybdenum chloride, and rhodium chloride were then dissolved in 10 mL of ethanol. After ultrasonic dispersion at room temperature, the ethanol was evaporated in an oil bath at 80 °C for 3 hours to obtain a uniformly mixed precursor salt powder. 5 g of sodium nitrate was weighed and added to a 30 mL crucible, which was heated in a muffle furnace at 380 °C for 10 minutes to obtain molten sodium nitrate. The uniformly mixed precursor salt was added to the molten sodium nitrate, and the reaction was carried out at 380 °C for 10 minutes. After natural cooling to room temperature, the mixture was thoroughly washed with alternating ultrapure water and ethanol to obtain molybdenum-rhodium co-doped ruthenium oxide nanoparticles, i.e., molybdenum-rhodium co-doped ruthenium oxide nanocatalysts.
[0040] Comparative Example 1
[0041] A ruthenium oxide nanocatalyst was prepared by the following method:
[0042] Add 5g of sodium nitrate to a 30mL crucible and preheat it in a muffle furnace at 380℃ for 10min to obtain molten sodium nitrate. Immediately add 40mg of ruthenium chloride to the molten sodium nitrate and continue to react in a muffle furnace at 380℃ for 10min. After the reaction is complete, allow it to cool naturally to room temperature and wash it thoroughly several times with ultrapure water and ethanol alternately to obtain ruthenium oxide nanoparticles, i.e., ruthenium oxide nanocatalyst.
[0043] The particle morphology of the prepared ruthenium oxide nanocatalyst was observed by TEM, and the results are as follows: Figure 1 (b)
[0044] Comparative Example 2
[0045] A molybdenum-doped ruthenium oxide nanocatalyst was prepared by the following method:
[0046] In a 50 mL beaker, 40 mg of ruthenium chloride and 5.3 mg of molybdenum chloride were added. The ruthenium chloride and molybdenum chloride were then dissolved in 10 mL of ethanol. After being ultrasonically dispersed evenly at room temperature, the ethanol was evaporated in an oil bath at 80 °C for 3 h to obtain a uniformly mixed precursor salt powder. 5 g of sodium nitrate was weighed and added to a 30 mL crucible. The crucible was preheated in a muffle furnace at 380 °C for 10 min to obtain molten sodium nitrate. The uniformly mixed precursor salt was added to the molten sodium nitrate, and the mixture was reacted at 380 °C for 10 min. After naturally cooling to room temperature, the mixture was thoroughly washed with alternating ultrapure water and ethanol to obtain molybdenum-doped ruthenium oxide nanoparticles, i.e., molybdenum-doped ruthenium oxide nanocatalysts.
[0047] The particle morphology of the prepared molybdenum-doped ruthenium oxide nanocatalyst was observed by TEM, and the results are as follows: Figure 1 (c)
[0048] Comparative Example 3
[0049] A rhodium-doped ruthenium oxide nanocatalyst was prepared by the following method:
[0050] In a 50 mL beaker, 40 mg of ruthenium chloride and 4 mg of rhodium chloride were added. The ruthenium chloride and rhodium chloride were then dissolved in 10 mL of ethanol and ultrasonically dispersed at room temperature. The ethanol was then evaporated in an oil bath at 80 °C for 3 h to obtain a uniformly mixed precursor salt powder. 5 g of sodium nitrate was weighed and added to a 30 mL crucible. The crucible was preheated in a muffle furnace at 380 °C for 10 min to obtain molten sodium nitrate. The uniformly mixed precursor salt was added to the molten sodium nitrate and reacted at 380 °C for 10 min. After naturally cooling to room temperature, the mixture was thoroughly washed with alternating ultrapure water and ethanol to obtain rhodium co-doped ruthenium oxide nanoparticles, i.e., rhodium co-doped ruthenium oxide nanocatalysts.
[0051] The particle morphology of the prepared rhodium-doped ruthenium oxide nanocatalyst was observed by TEM, and the results are as follows: Figure 1 (d)
[0052] Figure 3 This is a comparison of the electrocatalytic oxygen evolution activity in water electrolysis between the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in Example 1 of this invention and a commercial ruthenium oxide catalyst (C-RuO2). Figure 3 It can be seen that the Mo,Rh co-doped catalyst at a current density of 10 mA / cm² -2 The overpotential is only 160mV, which is better than that of Mo-RuO doped with Mo alone. x (183mV), Rh-doped Rh-RuO x (187mV), Homemade RuO x (190mV) and commercial RuO2 (315mV) indicate that Mo,Rh co-doped RuO x It exhibits optimal OER activity.
[0053] Figure 4 This is a chronopotential curve of oxygen evolution through water electrolysis between the molybdenum-rhodium co-doped ruthenium oxide nanoparticles prepared in Example 1 of this invention and a commercial ruthenium oxide catalyst (C-RuO2). Figure 4 The durability of the catalyst was tested using a chronopotentiometric method. As shown in the figure, at 100 mA / cm², the catalyst's durability is significantly improved. -2 At a current density of [value missing], the Mo,Rh co-doped catalyst maintained good stability after 350 h, which was superior to Mo-RuO [value missing]. x (60h), Rh-RuO x (320h), homemade RuO x (170h) and commercial RuO2 (8h); confirming that Mo,Rh co-doped ruthenium oxide has excellent practical application prospects.
[0054] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a molybdenum-rhodium co-doped ruthenium oxide nanocatalyst, characterized in that, Includes the following steps: (1) Disperse ruthenium precursor salt, molybdenum chloride and rhodium chloride evenly with organic solvent by ultrasonication. The molar ratio of ruthenium precursor salt, molybdenum chloride and rhodium chloride is 10: (0-1): (0-1). The content of molybdenum chloride and rhodium chloride is not 0. The amount of organic solvent added is 25-50 mL / 100 mg of ruthenium precursor salt. Then evaporate the organic solvent to remove it and obtain a uniformly mixed precursor salt powder. (2) Preheat the nitrate at 350-410 ℃ for 5-15 min to obtain molten nitrate; (3) Add the precursor salt powder obtained in step (1) to the molten nitrate obtained in step (2), react at 350-410 °C for 5-15 min, cool naturally to room temperature, and wash to obtain molybdenum-rhodium co-doped ruthenium oxide nanoparticles, which are molybdenum-rhodium co-doped ruthenium oxide nanocatalysts.
2. The preparation method according to claim 1, characterized in that, The organic solvent in step (1) is either ethanol or acetone.
3. The preparation method according to claim 1, characterized in that, In step (1), the ruthenium precursor salt is ruthenium chloride.
4. The preparation method according to claim 1, characterized in that, In step (2), the nitrate is either sodium nitrate or potassium nitrate.
5. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of precursor salt to molten nitrate is (30-80):(5000-10000).
6. The preparation method according to claim 1, characterized in that, In step (3), the washing process involves alternating between ultrapure water and ethanol.
7. A molybdenum-rhodium co-doped ruthenium oxide nanocatalyst prepared by the preparation method according to any one of claims 1-6.
8. The molybdenum-rhodium co-doped ruthenium oxide nanocatalyst as described in claim 7, characterized in that, The molar ratio of Ru:Mo:Rh in the molybdenum-rhodium co-doped ruthenium oxide nanocatalyst is (80-98): (1-10): (1-10).
9. The application of the molybdenum-rhodium co-doped ruthenium oxide nanocatalyst as described in claim 7 or 8 as an electrocatalyst in the electrocatalytic oxygen evolution of water electrolysis.