Preparation method and application of ruthenium ditelluride crystal-amorphous composite material
By preparing ruthenium ditelluride crystalline-amorphous composite materials, using the amorphous phase to provide abundant catalytic active centers and the crystalline phase to provide efficient charge transfer paths, the problem of scarce reserves of precious metal catalysts was solved, efficient and low-cost water electrolysis to produce hydrogen was achieved, and the development of clean energy technology was promoted.
Patent Information
- Application Number
- CN202510631920.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-16
- Publication Date
- 2025-09-16
AI Technical Summary
In the existing technology, the reserves of precious metal platinum (Pt) catalysts are scarce and expensive, resulting in high costs for hydrogen production by water electrolysis. In addition, there is insufficient research on the mechanism by which the crystallinity and interface structure of ruthenium ditelluride (RuTe2) materials affect their electrocatalytic performance.
By mixing tellurium nanowires with a ruthenium source for a solvent thermal reaction, followed by annealing, a ruthenium ditelluride crystalline-amorphous composite material is formed. Combined with appropriate annealing temperature and time, a crystalline-amorphous interface structure is constructed, and the electronic structure and charge transfer path are optimized.
The synergistic optimization of the rich active sites in the amorphous state and the high conductivity of the crystalline state was achieved, which improved the performance of the electrocatalytic hydrogen evolution reaction, provided an efficient and low-cost catalyst synthesis scheme, and laid the foundation for the clean energy system.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a preparation method and application of a ruthenium ditelluride crystalline-amorphous composite material. Background Art
[0002] The electrolysis of water to produce hydrogen uses abundant water as raw material and clean renewable energy as the source of electricity. The hydrogen production process is green and pollution-free. As a clean energy solution, it has been widely accepted and supported by the society. However, the electrolysis of water to produce hydrogen technology currently has problems such as high energy consumption (per 1m3 of hydrogen produced). 3 Hydrogen requires 5-7 kWh of electricity, resulting in high production costs. The precious metal platinum (Pt) is currently recognized as the best performing hydrogen evolution reaction (HER) catalyst. However, the scarcity and high cost of Pt-based catalysts restrict their widespread use in water electrolysis hydrogen production. Therefore, the search for new HER catalysts that can replace the precious metal Pt has become a current technological hotspot and challenge.
[0003] Among the many non-platinum catalysts, ruthenium (Ru)-based materials are considered promising alternatives for HER catalysts due to their unique d-electron structure, moderate metal-hydrogen bond strength (Pt-like characteristics), and relatively low price (approximately one-fifth that of Pt). Since Jaramillo et al. first reported the HER activity of Ru-based materials in acidic media in 2010, this field has experienced rapid development, with catalyst forms expanding from single metals to alloys, phosphides, oxides, and chalcogenides. Among them, Ru-based metal (selenium, tellurium) sulfides (RuX2, where X = S, Se, Te) have attracted considerable attention due to their excellent intrinsic conductivity and good electrochemical stability. Ruthenium ditelluride (RuTe2) is particularly noteworthy. Both theoretical and experimental studies have shown that the large radius and weak electronegativity of the Te atom endow the Ru-Te bond with an appropriate bond strength and unique electronic structure, which are beneficial for optimizing hydrogen adsorption and desorption kinetics, resulting in intrinsic activity in acidic HER that approaches or even exceeds that of Pt.
[0004] In recent years, ruthenium telluride has been widely studied as a new type of water electrolysis catalyst. Research on improving the catalytic performance of RuTe2 has mainly focused on several directions: (1) compounding with highly conductive supports (such as carbon materials) to improve electron transport and dispersion; (2) regulating electronic structure and introducing defect sites through heteroatom doping (such as N, B, P, etc.); (3) increasing specific surface area and exposing more active sites through morphology or nanostructure design (such as nanocrystals, core-shell structures, hollow structures, etc.). These strategies provide important ideas for improving the performance of RuTe2. However, most previous studies have focused on external structural modification or compounding with other species, while research on regulating the intrinsic structural parameters of RuTe2 materials themselves, especially crystallinity and its related interface structure, and systematically revealing the mechanism of their influence on HER performance is still relatively scarce.
[0005] It is well known that crystallinity is a key intrinsic factor that directly affects the electronic structure, defect state density, surface coordination environment and even catalytic activity of electrocatalytic materials. Studies have shown that in other catalytic systems (such as MoS2, CoP, etc.), although amorphous materials have abundant low-coordination active sites, they often have poor conductivity; while high-crystallinity materials have excellent conductivity but limited active site density. By constructing a crystalline / amorphous (C / A) heterogeneous interface, it is expected to combine the advantages of both: using the amorphous phase to provide abundant catalytic active centers, using the crystalline phase to ensure efficient charge transfer paths, and further optimizing the adsorption energy and reaction kinetics of the reaction intermediates through the special electronic structure at the interface (such as built-in electric field, orbital hybridization, stress / strain). However, how to accurately construct a crystal / amorphous composite material with an optimized interface structure in the RuTe2 system and deeply understand the core mechanism of the interface structure regulating HER performance remains a scientific problem that needs to be solved urgently. Summary of the Invention
[0006] In order to overcome at least one problem existing in the above-mentioned prior art, one of the objects of the present invention is to provide a method for preparing a crystalline-amorphous composite material of ruthenium ditelluride. The crystalline-amorphous composite material of ruthenium ditelluride prepared by this method has both the rich active sites of the amorphous state and the high electrical conductivity of the crystalline state, realizing the synergistic optimization of structure and performance, and the reaction raw materials are simple, the process flow is concise and easy to operate.
[0007] A second object of the present invention is to provide a ruthenium ditelluride crystalline-amorphous composite material.
[0008] A third object of the present invention is to provide an application of the above-mentioned ruthenium ditelluride crystalline-amorphous composite material.
[0009] In order to achieve the above object, the technical solution adopted by the present invention is:
[0010] A first aspect of the present invention provides a method for preparing a crystalline-amorphous composite material of ruthenium ditelluride, comprising the following steps: mixing tellurium nanowires, a ruthenium source, and a second solvent, performing a second solvothermal reaction, and obtaining a tellurium-ruthenium composite material; and annealing the tellurium-ruthenium composite material to obtain the crystalline-amorphous composite material of ruthenium ditelluride.
[0011] Preferably, the annealing temperature is 300-600°C; more preferably 350-550°C; further preferably 400-500°C; for example, it can be any value among 400°C, 420°C, 450°C, 470°C or 500°C or a range between any two of them.
[0012] Preferably, the holding time of the annealing treatment is 0.5 to 4 hours; more preferably 1 to 3 hours; even more preferably 1.5 to 2.5 hours; for example, it can be any value among 1.5 hours, 1.8 hours, 2 hours, 2.2 hours or 2.5 hours, or a range between any two of them.
[0013] Preferably, the heating rate of the annealing treatment is 1 to 10°C / min; more preferably 2 to 8°C / min; even more preferably 3 to 7°C / min; for example, it can be any value among 3°C / min, 4°C / min, 5°C / min, 6°C / min or 7°C / min, or a range between any two values.
[0014] Preferably, the annealing treatment is performed in a protective gas atmosphere.
[0015] Preferably, the protective gas comprises at least one of nitrogen, argon or helium; in some embodiments of the present invention, the protective gas is selected from argon.
[0016] Preferably, the temperature of the second solvent thermal reaction is 150-300°C; more preferably 170-280°C; further preferably 180-250°C; for example, it can be any value among 180°C, 200°C, 220°C or 250°C or a range between any two of them.
[0017] Preferably, the holding time of the second solvent thermal reaction is 1 to 3 hours; more preferably 1.5 to 2.5 hours; further preferably 1.7 to 2.3 hours; for example, it can be any value among 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, 2.1 hours, 2.2 hours or 2.3 hours, or a range between any two of them.
[0018] Preferably, the mass ratio of the tellurium nanowires to the ruthenium source is 1:(1-3); more preferably 1:(1.5-2.5); for example, it can be any value among 1:1.5, 1:1.8, 1:2, 1:2.2 or 1:2.5, or a range value between any two of them.
[0019] Preferably, the usage ratio of the tellurium nanowires to the second solvent is 1 mg: (1-10) mL; more preferably 1 mg: (1.5-7) mL; further preferably 1 mg: (2-5) mL; for example, it can be any value among 1 mg: 2 mL, 1 mg: 3 mL, 1 mg: 4 mL or 1 mg: 5 mL, or a range value between any two of them.
[0020] Preferably, the second solvent includes an alcohol solvent; further preferably, the second solvent is selected from alcohol solvents.
[0021] Preferably, the alcohol solvent in the second solvent includes at least one of ethanol, methanol or ethylene glycol; further preferably, the alcohol solvent in the second solvent is selected from ethylene glycol.
[0022] Preferably, the ruthenium source includes at least one of ruthenium trichloride, ruthenium acetate or ruthenium nitrate; further preferably, the ruthenium source is selected from ruthenium trichloride.
[0023] Preferably, after the second solvent thermal reaction, a second washing step is further included; further preferably, the reagents used in the second washing include water and ethanol (alcohol).
[0024] Preferably, the tellurium nanowires are prepared by a preparation method comprising the following steps: mixing a tellurium source, a reducing agent and a first solvent, and performing a first solvothermal reaction to obtain the tellurium nanowires.
[0025] Preferably, the temperature of the first solvent thermal reaction is 100-200°C; more preferably 120-180°C; further preferably 130-170°C; for example, it can be any value among 130°C, 140°C, 150°C, 160°C or 170°C or a range between any two of them.
[0026] Preferably, the holding time of the first solvent thermal reaction is 8 to 20 hours; more preferably 10 to 18 hours; even more preferably 12 to 15 hours; for example, it can be any value among 12 hours, 13 hours, 14 hours or 15 hours, or a range between any two of them.
[0027] Preferably, the molar ratio of the tellurium source to the reducing agent is 1:(30-50); more preferably 1:(35-45); for example, it can be any value among 1:35, 1:38, 1:40, 1:42 or 1:45 or a range between any two values.
[0028] Preferably, the usage ratio of the tellurium source to the first solvent is 1 mg: (0.1-2) mL; more preferably 1 mg: (0.3-1.5) mL; even more preferably 1 mg: (0.5-1) mL; for example, it can be any value among 1 mg: 0.5 mL, 1 mg: 0.6 mL, 1 mg: 0.8 mL or 1 mg: 1 mL, or a range value between any two of them.
[0029] Preferably, the first solvent includes water, an alcohol solvent or a combination thereof; further preferably, the first solvent includes water and an alcohol solvent; even more preferably, in the first solvent, the volume ratio of water to alcohol solvent is 1:(0.5~2); for example, it can be any value of 1:0.5, 1:1, 1:1.5 or 1:2 or a range value between any two of them.
[0030] Preferably, the alcohol solvent in the first solvent includes at least one of ethanol, methanol or ethylene glycol; further preferably, the alcohol solvent in the first solvent is selected from ethylene glycol.
[0031] Preferably, the tellurium source comprises at least one of tellurite, tellurate, or telluric acid. Further preferably, the tellurium source comprises tellurite, tellurate, or a combination thereof. Even more preferably, the tellurium source is selected from tellurites. Common tellurites include potassium tellurite and sodium tellurite. In some embodiments of the present invention, the tellurium source is selected from potassium tellurite.
[0032] Preferably, the reducing agent comprises at least one of glucose, fructose or ascorbic acid; further preferably, the reducing agent is selected from glucose.
[0033] Preferably, after the first solvent thermal reaction, a first washing step is further included; further preferably, the reagents used in the first washing include water and ethanol (alcohol).
[0034] Preferably, the length of the tellurium nanowire is 0.5 to 10 μm; more preferably 1 to 5 μm; even more preferably 1.5 to 3 μm; for example, it can be any value among 1.5 μm, 2 μm, 2.5 μm or 3 μm, or a range between any two of them.
[0035] Preferably, the diameter of the tellurium nanowire is 30 to 200 nm; more preferably 50 to 150 nm; even more preferably 70 to 120 nm; for example, it can be any value among 70 nm, 80 nm, 100 nm or 120 nm, or a range between any two of them.
[0036] The second aspect of the present invention provides a ruthenium ditelluride crystalline-amorphous composite material, which is prepared by the preparation method described in the first aspect of the present invention.
[0037] Preferably, the ruthenium ditelluride crystalline-amorphous composite material has a core-shell structure, wherein the core is tellurium nanowires and the shell includes a ruthenium ditelluride crystalline phase and a ruthenium ditelluride amorphous phase.
[0038] Preferably, the average grain size of the ruthenium ditelluride crystalline phase is 0.05 to 0.5 nm; more preferably 0.08 to 0.4 nm; even more preferably 0.09 to 0.35 nm; for example, it can be any value among 0.09 nm, 0.1 nm, 0.2 nm, 0.3 nm or 0.35 nm, or a range between any two of them.
[0039] Preferably, the crystallinity of the ruthenium ditelluride crystalline-amorphous composite material is 28-50%; more preferably 30-45%; for example, it can be any value among 30%, 32%, 35%, 38%, 40%, 42% or 45%, or a range value between any two of them.
[0040] The products produced by the present invention with moderate crystallinity (28-50%) exhibit improved catalytic performance due to their enhanced crystalline-amorphous interface structure. The unique electronic structure of the crystalline-amorphous interface optimizes the free energy of hydrogen adsorption and promotes charge transfer. This present invention establishes a comprehensive correlation between crystallinity, structure, and performance. This strategy of regulating catalytic activity through interface engineering offers new insights into the design of highly efficient non-precious metal catalysts. It also provides a practical, low-cost synthesis strategy for efficient catalysts, laying an important foundation for building a future clean energy system.
[0041] The third aspect of the present invention provides a use of the ruthenium ditelluride crystalline-amorphous composite material as described in the first aspect of the present invention in an electrocatalytic hydrogen evolution reaction.
[0042] The beneficial effects of the present invention are as follows: the present invention uses tellurium nanowires as a template, synthesizes a tellurium ruthenium complex through a solvent thermal reaction, and then combines it with annealing treatment to form a ruthenium ditelluride crystalline-amorphous composite material. The amorphous phase can provide rich catalytic active centers, and the crystalline phase can ensure an efficient charge transfer path. The composite material has both the rich active sites of the amorphous state and the high electrical conductivity of the crystalline state, achieving synergistic optimization of structure and performance, and has good application prospects in the electrocatalytic hydrogen evolution reaction.
[0043] Specifically, compared with the prior art, the present invention has the following advantages:
[0044] 1. The unique electronic structure of the crystalline-amorphous interface region of the ruthenium ditelluride composite material of the present invention optimizes the hydrogen adsorption free energy and promotes charge transfer. This invention establishes a comprehensive correlation between crystallinity, structure, and performance. This strategy of regulating catalytic activity through interface engineering provides a new approach to designing efficient non-precious metal catalysts. It also offers a practical technical solution for synthesizing high-efficiency, low-cost catalysts, laying an important foundation for building a future clean energy system.
[0045] 2. The present invention achieves structural regulation from crystalline Te-amorphous Ru complex to crystalline-amorphous coexisting RuTe2 and then to highly crystalline RuTe2 by precisely controlling the annealing temperature; the use of a suitable annealing temperature is conducive to obtaining products with better catalytic performance.
[0046] 3. The preparation method provided by the present invention has simple raw materials, a concise process, is easy to operate, is suitable for large-scale preparation, and the reaction process is green and safe without other toxic additives. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Figure 1 The XRD patterns of the samples in Control Example 1 and Examples 1 to 4 are shown.
[0048] Figure 2 This is a scanning electron microscope image of the sample in Example 2.
[0049] Figure 3 Scanning electron microscope images of the samples in Examples 2, 5, and 6.
[0050] Figure 4 This is a transmission electron microscope image of the sample in Example 2.
[0051] Figure 5 This is a high-resolution transmission electron microscope image of the sample in Control Example 1.
[0052] Figure 6 The linear sweep voltammetry polarization curves of the samples of Examples 1 to 4 and Comparative Examples 1 to 2 at a scan rate of 10 mV / s are shown.
[0053] Figure 7 These are the linear sweep voltammetry polarization curves of the samples in Examples 1 and 5-6 at a scan rate of 10 mV / s.
[0054] Figure 8 This is the stability test curve of the sample in Example 2. DETAILED DESCRIPTION
[0055] The content of the present invention is further described in detail below through specific examples. It should be understood that the following examples are only used to further illustrate the present invention and cannot be interpreted as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles set forth in the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, and those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific data exemplified below. The raw materials, reagents or devices used in the following examples and comparative examples, unless otherwise specified, can be obtained from conventional commercial sources, or can be obtained by existing known methods.
[0056] Example 1
[0057] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, comprising the following specific steps:
[0058] (1) 50 mg of potassium tellurite and 1.5 g of glucose were dissolved in 15 mL of deionized water and 15 mL of ethylene glycol, and the mixture was stirred until the potassium tellurite was completely dissolved to obtain a first mixed solution.
[0059] (2) The first mixed solution is placed in a reactor and reduced under high temperature and pressure to produce tellurium nanowires at 150° C. for 12 hours. The product is collected by centrifugation and washed several times with deionized water and alcohol to obtain tellurium nanowires. The synthesized tellurium nanowires have a uniform, elongated one-dimensional structure, a length of approximately 1.5 to 3 μm, a diameter of approximately 70 to 120 nm, and a highly crystalline single crystal structure.
[0060] (3) Dissolve 10 mg of tellurium nanowires and 20 mg of ruthenium trichloride in 30 mL of ethylene glycol and stir until completely dissolved to obtain a second mixed solution.
[0061] (4) The second mixed solution is placed in a reactor under high temperature and high pressure, and the reduced precious metal ruthenium is attached to the tellurium nanowires. The heating temperature is 200°C and the heating time is 2 hours. The product is collected by centrifugation and washed several times with deionized water and alcohol to obtain a tellurium nanowire-loaded precious metal Ru composite material, which is recorded as RuTe2@Te.
[0062] (5) The RuTe2@Te prepared was annealed by heating to 300°C at a heating rate of 5°C / min in an argon environment and annealing for 2 h to obtain the final product.
[0063] Example 2
[0064] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, which differs from Example 1 in that the annealing temperature in the argon environment in step (5) is changed to 400°C, and the remaining preparation materials and steps are the same as those in Example 1.
[0065] Example 3
[0066] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, which differs from Example 1 in that the annealing temperature in step (5) under an argon environment is changed to 500°C, and the remaining preparation materials and steps are the same as those in Example 1.
[0067] Example 4
[0068] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, which differs from Example 1 in that the annealing temperature in step (5) under an argon environment is changed to 600°C, and the remaining preparation materials and steps are the same as those in Example 1.
[0069] Example 5
[0070] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, which differs from Example 2 in that the hydrothermal time of the second mixed solution in step (4) is changed to 1 hour in this embodiment, and the remaining preparation raw materials and steps are the same as those in Example 2.
[0071] Example 6
[0072] A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, which differs from Example 2 in that the hydrothermal time of the second mixed solution in step (4) is changed to 3 hours in this embodiment, and the remaining preparation materials and steps are the same as those in Example 2.
[0073] Comparative Example 1
[0074] A method for preparing a tellurium nanowire-loaded precious metal Ru composite material is different from Example 1 in that the control example does not perform the annealing treatment under an argon environment in step (5), and the remaining preparation materials and steps are the same as Example 1.
[0075] Comparative Example 2
[0076] Commercial Pt / C (20% wt).
[0077] Performance Testing
[0078] 1. Characterization of the morphology and structure of the composite materials: X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the microstructure and interface structure of the composite materials of the examples and the comparative examples in detail.
[0079] System XRD analysis ( Figure 1) confirmed the crystalline / amorphous structure evolution of the composite material. Figure 1 The following are the XRD patterns of the samples in Control Example 1 and Examples 1-4. As can be seen, the XRD pattern of Control Example 1 primarily displays the characteristic diffraction peak of Te, accompanied by a weak characteristic peak of RuTe2, indicating that the initial sample is primarily composed of crystalline Te and amorphous Ru. In Examples 1-4, however, as the annealing temperature increases, the characteristic peak of Te gradually weakens, while the characteristic diffraction peak of RuTe2 (corresponding to standard card PDF#44-1015) becomes more intense and its full width at half maximum (FWHM) decreases, clearly demonstrating the transformation from Te / Ru to RuTe2 and the gradual increase in RuTe2 crystallinity.
[0080] It is worth noting the intensity evolution of the 27.8° (020) peak: compared with Control Example 1 and Example 1, the characteristic peak of Example 1 disappears, indicating that a bonding reaction occurs between crystalline Te and amorphous Ru during the annealing process. Afterwards, as the annealing temperature increases, the intensity of the characteristic peak corresponding to the (020) crystal plane increases. This may be due to the higher pyrolysis temperature (≥400°C), which drives the significant transformation from amorphous to crystalline, and the crystallinity continues to increase. The (111) crystal plane diffraction peak at 31.2° also shows a similar trend, that is, the intensity increases significantly from 400°C, further confirming the law that the crystallinity increases with temperature.
[0081] To quantitatively characterize the change in crystallinity, the Scherrer equation (D = Kλ / βcosθ, where K is the shape factor 0.9 and λ is the X-ray wavelength) was applied. β is the half-peak width, θ is the diffraction angle) and the average grain size of the RuTe2(111) crystal plane at 27.8° was calculated. As shown in Table 1, the grain sizes of the samples of Examples 1 to 4 are 0.082nm, 0.09nm, 0.324nm and 0.405nm, respectively, showing an obvious growth trend. Combining the diffraction peak intensity, the peak area method was used to fit the diffraction peak area and estimate the crystallinity ratios of the samples in Control Example 1 and Examples 1 to 4 to be <10%, 25±5%, 32±5%, 44±5% and 70±5%, respectively. These results directly prove that the crystallinity of RuTe2 can be precisely controlled by annealing treatment and controlling the annealing temperature.
[0082] Table 1 Grain size and estimated crystallinity of samples in Comparative Example 1 and Examples 1 to 4
[0083] sample Annealing temperature (℃) Particle size (nm) Estimated crystallinity (%) Comparative Example 1 - - <10 Example 1 300 0.082 25±5 Example 2 400 0.09 32±5 Example 3 500 0.324 44±5 Example 4 600 0.405 70±5
[0084] Figure 2The following are scanning electron microscope (SEM) images of the sample in Example 2; a is a low-resolution image; b is a high-resolution image. The SEM images show that the sample in Example 2 maintains a one-dimensional nanowire morphology, indicating that the annealing process did not destroy the overall morphology of the material. It is worth noting that the surface roughness of the sample increases after annealing, and a porous structure is formed, which is mainly due to the Te / Ru interface reaction and atomic rearrangement process. This porous morphology is beneficial for increasing the specific surface area, providing more exposed active sites, and improving catalytic performance.
[0085] In order to optimize the synthesis conditions, the effect of hydrothermal time on the microstructure of the product was systematically investigated. Figure 3 Scanning electron microscope (SEM) images of samples from Examples 2, 5, and 6 are shown; a is from Example 5; b is from Example 2; and c is from Example 6. Comparative experimental results show that a 2-hour hydrothermal time yields the best-looking product. This can be attributed to insufficient Ru loading and incomplete growth on the Te nanowires at a 1-hour reaction time. Extending the reaction time to 3 hours results in excessive growth or aggregation of the material under prolonged high-temperature and high-pressure conditions, reducing the dispersion and uniformity of the product.
[0086] Figure 4 The transmission electron microscope (TEM) image of the sample in Example 2 is shown in Figure 2; a is a low-resolution image; b is a high-resolution (HRTEM) image of the outer shell. The HRTEM image of Example 2 shows that the sample has a core-shell structure, with the inner core being Te nanowires and the outer shell being RuTe2 in which crystalline and amorphous coexist. There are both ordered lattice regions and disordered amorphous regions in the material, forming a clear crystalline-amorphous interface structure. Two types of regions are marked in the HRTEM image of Example 2: the crystalline region (marked as "Crystalline") shows regular lattice fringes with a fringing spacing of 0.276nm and 0.319nm, corresponding to the (120) and (020) crystal planes of RuTe2, respectively; the amorphous region (marked as "Amorphous") shows typical disordered characteristics. Figure 4 The crystal-amorphous coexistence characteristics of Example 2 were confirmed.
[0087] Figure 5 This is a high-resolution transmission electron microscopy (HRTEM) image of the outer shell of the sample from Control Example 1. The sample from Control Example 1 exhibits a typical core-shell structure. Te lattice fringes can be observed in the core region of the HRTEM image, while the outer shell region is disordered and lacks distinct lattice fringes, confirming that Te in the initial sample is crystalline while Ru is primarily amorphous.
[0088] 2. Electrochemical hydrogen evolution performance test results
[0089] To investigate the effect of gradient annealing under argon on the hydrogen evolution catalytic performance of ruthenium telluride (RuTe2) and to systematically evaluate the effect of crystallinity on RuTe2 catalytic performance, the composite materials from Examples 1-6 and Comparative Examples 1-2 were tested for hydrogen evolution reaction (HER) performance in a standard three-electrode system using 0.5M H2SO4 electrolyte. The specific steps are as follows: 1) Working electrode preparation: 3mg of the composite material sample and 0.6mg of carbon black were dispersed in a mixture of 0.084mL of water, 0.48mL of isopropanol, and 0.016mL of 5wt.% Nafion. After ultrasonic homogenization, 19.5µL of the suspension was dropwise applied to a polished glassy carbon electrode. After air drying, electrocatalytic testing was performed. 2) Hydrogen evolution performance testing: Hydrogen evolution performance was tested on an electrochemical workstation using a catalyst-loaded glassy carbon electrode as the working electrode, saturated calomel (SCE) as the reference electrode, a carbon rod as the counter electrode, and 0.5M H2SO4 aqueous solution as the electrolyte. The hydrogen evolution catalytic performance was evaluated using polarization curves. By applying 10 mA cm -2 The working current density is used to measure the change of electrode voltage over time (more than 10 hours), that is, the electrochemical hydrogen evolution stability of the catalyst is evaluated through the chronopotentiometry curve.
[0090] Figure 6 The linear sweep voltammetry (LSV) polarization curves of the samples of Examples 1 to 4 and Comparative Examples 1 to 2 at a sweep rate of 10 mV / s are shown in Figure 2. -2 The corresponding hydrogen evolution overpotentials are 135 mV, 81 mV, 97 mV, 139 mV, 123 mV and 84 mV, respectively. Compared with Examples 1, 3, 4 and Control Example 1, Example 2 shows significantly better catalytic performance for hydrogen evolution reaction.
[0091] In order to investigate the effect of the hydrothermal time of the second mixed solution on the hydrogen evolution performance of ruthenium telluride, a performance comparison was conducted. Figure 7 The linear sweep voltammetry (LSV) polarization curves of samples 1 and 5 to 6 at a sweep rate of 10 mV / s are shown in Figure 2. -2 The corresponding hydrogen evolution overpotentials are 81 mV, 124 mV, and 130 mV, respectively; Example 2 exhibits significantly better catalytic performance for hydrogen evolution reaction than Examples 5-6.
[0092] For the convenience of comparison, the samples of Examples 1 to 6 and Comparative Examples 1 to 2 were tested at 50 mA·cm -2 The hydrogen evolution overpotential data at different current densities are listed in Table 2.
[0093] Table 2 Examples and Comparative Examples at 50 mA·cm -2 Hydrogen evolution overpotential data at current density
[0094] Hydrogen evolution overpotential mV Example 1 135 Example 2 81 Example 3 97 Example 4 139 Example 5 124 Example 6 130 Comparative Example 1 123 Comparative Example 2 84
[0095] To evaluate the stability of the catalyst under more severe conditions, the stability of the sample of Example 2 was comprehensively evaluated by accelerated stability testing and long-term chronoamperometric measurement. Figure 8 The stability test curve of the sample in Example 2; a is the polarization curve comparison of the sample in Example 2 before and after 2,000 cycles; b is the polarization curve comparison of the sample in Example 2 at 10 mA·cm -2 It curve of 80h under current density. Figure 7 Comparing the LSV polarization curves before and after 2000 continuous cycles, it can be seen that the sample of Example 2 exhibits extremely high cycle stability; and from the it curve, it can be seen that at 10 mA·cm -2 Under a constant current density of , Example 2 can maintain a stable potential output, showing excellent long-term stability.
[0096] In the ruthenium ditelluride crystalline-amorphous composite material prepared in this embodiment of the present invention, the unique electronic structure of the crystalline-amorphous interface region optimizes the hydrogen adsorption free energy and promotes charge transfer. Furthermore, this embodiment of the present invention establishes a complete correlation between crystallinity, structure, and performance. This strategy of regulating catalytic activity through interface engineering provides a new approach to designing efficient non-precious metal catalysts. It also provides a practical technical solution for the synthesis of efficient and low-cost catalysts, laying an important foundation for building a future clean energy system.
[0097] In Examples 1 to 4 of the present invention, by precisely controlling the annealing temperature, structural regulation from crystalline Te-amorphous Ru complex to crystalline-amorphous coexisting RuTe2 and then to highly crystalline RuTe2 is achieved; using a suitable annealing temperature is conducive to obtaining products with better catalytic performance.
[0098] The preparation method provided in the embodiment of the present invention has simple raw materials, a concise process, is easy to operate, is suitable for large-scale preparation, and the reaction process is green and safe without other toxic additives.
[0099] In summary, the present invention uses tellurium nanowires as templates to synthesize tellurium ruthenium complexes through a solvothermal reaction, and then combines it with annealing treatment to form a crystalline-amorphous ruthenium ditelluride composite material. The amorphous phase can provide rich catalytic active centers, and the crystalline phase can ensure an efficient charge transfer path. This composite material has both the rich active sites of the amorphous state and the high conductivity of the crystalline state, achieving synergistic optimization of structure and performance, and has good application prospects in the electrocatalytic hydrogen evolution reaction.
Claims
1. A method for preparing a ruthenium ditelluride crystalline-amorphous composite material, characterized in that: The following steps are involved: The tellurium nanowires, the ruthenium source and the second solvent are mixed and subjected to a second solvent thermal reaction to obtain a tellurium-ruthenium complex; the tellurium-ruthenium complex is annealed to obtain the ruthenium ditelluride crystalline-amorphous composite material.
2. The preparation method according to claim 1, characterized in that The annealing temperature is 300-600°C; And / or, the holding time of the annealing treatment is 0.5 to 4 hours; And / or, the heating rate of the annealing treatment is 1 to 10°C / min; And / or, the annealing treatment is performed in a protective gas atmosphere.
3. The preparation method according to claim 1, characterized in that The temperature of the second solvent thermal reaction is 150 to 300° C.; And / or, the holding time of the second solvent thermal reaction is 1 to 3 hours.
4. The preparation method according to claim 1, characterized in that The mass ratio of the tellurium nanowire to the ruthenium source is 1: (1～3)； And / or, the ratio of the tellurium nanowires to the second solvent is 1 mg: (1-10) mL.
5. The preparation method according to claim 1, characterized in that The tellurium nanowires are prepared by a preparation method comprising the following steps: mixing a tellurium source, a reducing agent and a first solvent, and performing a first solvent thermal reaction to obtain the tellurium nanowires.
6. The preparation method according to claim 5, characterized in that The temperature of the first solvent thermal reaction is 100 to 200° C.; and / or, the holding time of the first solvent thermal reaction is 8 to 20 hours; and / or, the molar ratio of the tellurium source to the reducing agent is 1:(30-50); and / or, the ratio of the tellurium source to the first solvent is 1 mg: (0.1-2) mL; And / or, the reducing agent includes at least one of glucose, fructose or ascorbic acid.
7. The preparation method according to claim 1, characterized in that The length of the tellurium nanowire is 0.5 to 10 μm; And / or, the diameter of the tellurium nanowire is 30-200 nm.
8. A ruthenium ditelluride crystalline-amorphous composite material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.
9. The ruthenium ditelluride crystalline-amorphous composite material according to claim 8, characterized in that: The ruthenium ditelluride crystalline-amorphous composite material has a core-shell structure, wherein the core is a tellurium nanowire and the shell comprises a ruthenium ditelluride crystalline phase and a ruthenium ditelluride amorphous phase; the average grain size of the ruthenium ditelluride crystalline phase is 0.05 to 0.5 nm; And / or, the crystallinity of the ruthenium ditelluride crystalline-amorphous composite material is 28-50%.
10. Use of the ruthenium ditelluride crystalline-amorphous composite material according to claim 8 or 9 in an electrocatalytic hydrogen evolution reaction.