A carbon-based self-supporting electrode and a method for preparing the same

Abstract

The present application relates to a kind of carbon-based self-supporting electrode and its preparation method, the carbon-based self-supporting electrode includes: carbon cloth and the vanadium disulfide nanosheet loaded with metal ruthenium cluster in situ grown on the carbon cloth.

Description

Technical Field

[0001] This invention belongs to the fields of energy conversion and electrocatalysis technology, specifically relating to a carbon-based self-supporting electrode and its preparation method. Background Technology

[0002] Metal-support interaction-based composite materials have broad application prospects in energy storage and conversion. Commonly, metal particles are mostly supported on the surface of the support. With changes in the external environment, surface-supported catalysts are prone to agglomeration, leading to deterioration or even deactivation of the metal particles in the composite material. Furthermore, the supported metal is susceptible to electrochemical oxidation, resulting in an oxide layer on its surface, which significantly reduces its activity and stability. Therefore, conventional metal-support interaction electrocatalysts exhibit problems such as uncontrollable catalytic performance or sudden deactivation during preparation and application. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a carbon-based self-supporting electrode and its preparation method. Specifically, a ruthenium-based vanadium disulfide catalyst is grown on the surface of carbon cloth to form a self-supporting electrode, aiming to comprehensively solve the shortcomings of metal-carrier composite materials, such as easy agglomeration of metal particles and sudden deactivation caused by electrochemical oxidation.

[0004] In a first aspect, the present invention provides a carbon-based self-supporting electrode, comprising a carbon cloth and vanadium disulfide nanosheets loaded with ruthenium clusters grown in situ on the carbon cloth.

[0005] Preferably, the carbon cloth is commercially available carbon cloth purchased from Shanghai Hesen Electric Co., Ltd.

[0006] Preferably, the particle size of the ruthenium clusters is 1-10 nm; the weight of the vanadium disulfide nanosheets loaded with ruthenium clusters is 100 wt%, and the loading amount of the ruthenium clusters is 1-5 wt%.

[0007] Preferably, the size of the vanadium disulfide nanosheets loaded with ruthenium clusters is 50-100 nm × 40-80 nm × 3-6 nm; with a carbon-based self-supporting electrode of 100 wt%, the content of the vanadium disulfide nanosheets loaded with ruthenium clusters is 40-80 wt%.

[0008] Secondly, the present invention provides a simple method for preparing a binder-free self-supporting electrode, comprising the following steps:

[0009] (1) Preparation of precursor solution: Weigh out vanadium source, sulfur source and ruthenium source respectively and disperse them in deionized water to form precursor solution;

[0010] (2) Place the cut carbon arrangement in a concentrated nitric acid solution and stir. Then wash and dry it with deionized water and anhydrous ethanol in sequence.

[0011] (3) The precursor solution is transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene. At the same time, carbon cloth is placed vertically in the reactor as a substrate material. The reactor is heated and kept warm. After the reactor cools to room temperature, the sample is taken out and washed with deionized water and anhydrous ethanol in sequence, and then dried.

[0012] Preferably, in step (1), the mass ratio of the vanadium source, sulfur source and ruthenium source is 15-20:10-20:1-3.

[0013] Preferably, in step (1), the vanadium source is sodium vanadate, the sulfur source is thioacetamide, and the ruthenium source is ruthenium chloride trihydrate.

[0014] Preferably, in step (1), the concentration of vanadium ions in the precursor solution is 1 to 10 mol / L.

[0015] Preferably, in step (2), the size of the cut commercial carbon cloth is 1-3cm × 1-3cm.

[0016] Preferably, in step (2), the concentration of the concentrated nitric acid can be 8 to 16 mol / L.

[0017] Preferably, in step (3), the heating temperature is 180-240°C and the holding time is 18-30h.

[0018] Beneficial effects

[0019] In this invention, ruthenium clusters anchored on the surface of vanadium disulfide nanosheets effectively enhance interfacial charge transport through metal-support interactions, while the construction of ruthenium clusters avoids the aggregation effect of metal atoms. Furthermore, the carbon substrate and support have different work functions, leading to charge transfer upon contact, which facilitates tunable electronic structure of reaction sites and thus controllable catalytic activity. In addition, the electrochemically oxidized ruthenium dioxide encapsulation layer serves as both an active center and protects the internal core, achieving a stable ruthenium / ruthenium dioxide core-shell structure, thereby enhancing the catalytic activity, selectivity, and stability of the material. Attached Figure Description

[0020] Figure 1 This is a low-resolution scanning electron microscope image of ruthenium clusters anchored on vanadium disulfide nanosheets composite carbon cloth in Example 1.

[0021] Figure 2 This is a high-resolution scanning electron microscope image of ruthenium clusters anchored on vanadium disulfide nanosheets composite carbon cloth in Example 1.

[0022] Figure 3 X-ray diffraction patterns of the vanadium disulfide-supported ruthenium cluster composite carbon cloth of Example 1 and the pure carbon cloth of Comparative Example 1 are shown.

[0023] Figure 4 Transmission electron microscopy image of ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1;

[0024] Figure 5 This is a high-resolution transmission electron microscope image of ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1.

[0025] Figure 6 X-ray photoelectron spectroscopy (XPS) analysis of the ruthenium metal clusters anchored on vanadium disulfide nanosheets in Example 1.

[0026] Figure 7 This is a high-resolution transmission electron microscope image of the ruthenium disulfide-supported vanadium clusters in Example 1 after electrochemical oxidation.

[0027] Figure 8 The images show the in-situ Raman spectra of ruthenium clusters at different potentials during the electrochemical oxidation process in Example 1.

[0028] Figure 9 The X-ray photoelectron spectroscopy (XPS) spectra of ruthenium clusters at different potentials during the electrochemical oxidation process in Example 1 are shown.

[0029] Figure 10 The image shows a scanning electron microscope (SEM) image of pure commercial carbon cloth, which is shown in Comparative Example 1.

[0030] Figure 11 The cycle life of the vanadium disulfide-supported ruthenium cluster composite carbon cloth of Example 1 and the pure carbon cloth of Comparative Example 1 as positive electrode materials for zinc-air batteries is compared.

[0031] Figure 12 High-resolution scanning electron microscope image of vanadium disulfide-supported ruthenium cluster composite carbon cloth, as shown in Comparative Example 2.

[0032] Figure 13 High-resolution scanning electron microscope image of vanadium disulfide-supported ruthenium cluster composite carbon cloth, as shown in Comparative Example 3.

[0033] Figure 14 High-resolution scanning electron microscope image of vanadium disulfide-supported ruthenium cluster composite carbon cloth, as shown in Comparative Example 4.

[0034] Figure 15 High-resolution scanning electron microscope image of vanadium disulfide-supported ruthenium cluster composite carbon cloth, Comparative Example 5.

[0035] Figure 16 High-resolution scanning electron microscope image of vanadium disulfide-supported ruthenium cluster composite carbon cloth, as shown in Comparative Example 6.

[0036] Figure 17 This is a high-resolution scanning electron microscope image of the vanadium disulfide-supported ruthenium cluster composite carbon cloth of Comparative Example 7. Detailed Implementation

[0037] To further illustrate the invention's content, features, and practical effects, the invention will be described in detail below with reference to embodiments. It should be noted that the modification methods of the invention are not limited to these specific implementation methods. Equivalent substitutions and modifications made by those skilled in the art based on their reading of the invention's content, without departing from the spirit and essence of the invention, are also within the scope of protection claimed by this invention.

[0038] This invention provides a carbon-based self-supporting electrode, comprising carbon cloth and vanadium disulfide nanosheets loaded with ruthenium clusters grown in situ on the carbon cloth. The ruthenium clusters anchored on the vanadium disulfide surface readily undergo electrochemical oxidation, encapsulating a protective layer primarily composed of ruthenium dioxide on their surface, while the interior of the clusters retains pure ruthenium.

[0039] The ruthenium clusters have a particle size of 1–10 nm; the weight of the vanadium disulfide nanosheets loaded with ruthenium clusters is 100 wt%, and the loading amount of the ruthenium clusters is 1–5 wt%.

[0040] The vanadium disulfide nanosheets loaded with ruthenium clusters have a size of 50-100 nm × 40-80 nm × 3-6 nm; with a carbon-based self-supporting electrode of 100 wt%, the content of the vanadium disulfide nanosheets loaded with ruthenium clusters is 40-80 wt%.

[0041] This invention uses carbon cloth as the substrate material, with vanadium disulfide nanosheets vertically grown on a carbon fiber framework and serving as a carrier for ruthenium clusters, thereby constructing a ruthenium cluster-anchored vanadium disulfide composite carbon cloth self-supporting electrode. Charge transfer exists between the metal clusters with different work functions and the vanadium disulfide carrier, allowing for the tuning of the surface electronic structure of the metal clusters. This material has wide applications in catalysis and energy storage. The following exemplarily illustrates the preparation method of the ruthenium-anchored vanadium disulfide composite carbon cloth self-supporting electrode provided by this invention:

[0042] (1) Preparation of precursor solution: Vanadium source, sulfur source and ruthenium source were weighed and dissolved in deionized water, and ultrasonically treated to disperse them evenly to form precursor solution.

[0043] The mass ratio of the vanadium source, sulfur source, and ruthenium source is 15-20:10-20:1-3; the vanadium source is sodium vanadate, the sulfur source is thioacetamide, and the ruthenium source is ruthenium chloride trihydrate.

[0044] The volume of the deionized water is 50–100 mL; the concentration of vanadium ions in the precursor solution is 1–10 mol / L.

[0045] The ultrasonic power is 100-300W, and the duration is 10-60 minutes.

[0046] (2) Treatment of carbon cloth: The cut carbon cloth is placed in a concentrated nitric acid solution and stirred magnetically at low speed. It is then washed with deionized water and anhydrous ethanol in sequence, and then placed in a drying oven to dry.

[0047] The cut carbon cloth has a size of 1-3cm × 1-3cm, preferably 2cm × 2cm.

[0048] The concentration of the concentrated nitric acid is 8–16 mol / L.

[0049] The low-speed magnetic stirring is performed at a speed of 100–1000 rpm for a duration of 30–60 min.

[0050] The drying temperature is 60–90°C, preferably 80°C, and the drying time is 0.5–3 hours, preferably 1 hour.

[0051] (3) Transfer the precursor solution to a stainless steel high-pressure reactor lined with polytetrafluoroethylene. At the same time, place the carbon cloth vertically into the reactor as a substrate material. Heat and keep warm. After the reactor cools to room temperature, take out the sample, wash it with deionized water and anhydrous ethanol in sequence, and then put it in a drying oven to dry.

[0052] The heating temperature is 180–240℃, and the holding time is 18–30 hours.

[0053] The drying temperature is 60-90℃, preferably 80℃, and the drying time is 6-18h, preferably 12h.

[0054] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0055] Example 1

[0056] (1) Preparation of precursor solution: 1.3 mg of ruthenium chloride trihydrate, 18 mg of sodium vanadate and 15.4 mg of thioacetamide were weighed and dissolved in 80 mL of deionized water. The solutions were ultrasonically treated to disperse them evenly and form a precursor solution with a vanadium concentration of 2.5 mol / L. The loading of ruthenium clusters was 2.3 wt%, the ultrasonic power was 150 W and the time was 30 min.

[0057] (2) Treatment of carbon cloth: Cut 2cm×2cm carbon cloth and stir it magnetically at low speed in 16mol / L concentrated nitric acid solution. Then wash it with deionized water and anhydrous ethanol in sequence, and dry it in an 80℃ drying oven for 1h. The speed of the low-speed magnetic stirring is 500rpm and the time is 45min.

[0058] (3) Transfer the precursor solution to a 100mL stainless steel high-pressure reactor lined with polytetrafluoroethylene. At the same time, place the carbon cloth vertically into the reactor as a substrate material. Heat to 220℃ and keep warm for 24h. After the reactor cools to room temperature, take out the sample and wash it with deionized water and anhydrous ethanol in sequence. Then put it in an 80℃ drying oven and dry for 12h.

[0059] Figure 1 The image shows a low-resolution scanning electron microscope (SEM) image of ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1. As can be seen from the image, each carbon fiber skeleton is coated with a layer of vanadium disulfide, and the tight interfacial contact facilitates the rapid transfer of electrons.

[0060] Figure 2 This is a high-resolution scanning electron microscope image of ruthenium clusters anchored on vanadium disulfide nanosheets composite carbon cloth in Example 1. The ultrathin nanosheet structure of vanadium disulfide serves as a carrier, providing ample space for the loading of ruthenium clusters.

[0061] Figure 4 The image shown is a transmission electron microscope (TEM) image of ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1. It can be observed that many ruthenium clusters are uniformly dispersed on the surface of vanadium disulfide nanosheets, and the size of the clusters is about 1 to 10 nm.

[0062] Figure 5 The image shown is a high-resolution transmission electron microscope (TEM) image of ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1. The lattice fringes show a lattice spacing of 0.20 nm corresponding to the (101) crystal plane of hexagonal ruthenium. Due to the hexagonal packing structure of ruthenium, the (111) plane preferentially appears along the beam diffraction direction of the same region axis, thus a large number of diffraction crystal planes can be observed. In addition, the lattice parameters of 0.256 nm and 0.202 nm can be matched with the (011) and (012) crystal planes of vanadium disulfide, which is consistent with the results of phase analysis.

[0063] Figure 6 The image shows the X-ray photoelectron spectroscopy (XPS) analysis of the ruthenium clusters anchored on vanadium disulfide nanosheets in Example 1. The presence of ruthenium-sulfur and ruthenium-ruthenium metallic bonds is evident, indicating a metal-support interaction at the interface between the ruthenium clusters and vanadium disulfide, while the internal structure of the clusters remains purely ruthenium. The ruthenium-vanadium disulfide interaction promotes charge transfer, thereby accelerating the electrocatalytic reaction kinetics.

[0064] Figure 7 This is a high-resolution transmission electron microscope (TEM) image of the ruthenium disulfide-supported vanadium clusters from Example 1 after electrochemical oxidation. The image shows the oxide encapsulation layer surrounding the ruthenium clusters, with 1 to 5 oxide layers. The vanadium disulfide nanosheets remain stable during electrochemical oxidation without significant changes. During electrochemical oxidation, metallic ruthenium is converted to ruthenium dioxide at the edges. Ruthenium dioxide acts as a catalytic site, effectively adsorbing / desorbing oxygen-containing intermediates and accelerating the transport kinetics during the electrochemical reaction. Furthermore, the electrochemical encapsulation layer effectively protects the internal metallic ruthenium from further corrosion, forming a typical core-shell structure with the ruthenium dioxide oxide layer, regulating the surface electronic configuration, thereby optimizing catalytic activity and stability.

[0065] Figure 8 The images show in-situ Raman spectra at different potentials during the electrochemical oxidation of ruthenium clusters in Example 1. As the voltage increases, the ruthenium-oxygen bond gradually strengthens, indicating that the ruthenium dioxide content gradually increases.

[0066] Figure 9 The image shows X-ray photoelectron spectroscopy (XPS) analysis at different potentials during the electrochemical oxidation of ruthenium clusters in Example 1. It can be clearly observed from the image that as the voltage increases, ruthenium-oxygen bonds begin to appear and gradually strengthen, while the corresponding ruthenium-ruthenium bonds gradually weaken. However, at a high potential of 1.5V, the presence of ruthenium-ruthenium bonds can still be observed, indicating that some ruthenium is oxidized to ruthenium dioxide.

[0067] Example 2

[0068] In this Example 2, the preparation method of the carbon-based self-supporting electrode is the same as in Example 1, except that the content of the ruthenium source is reduced to keep its loading at 1 wt%, and 0.8 mg of ruthenium chloride trihydrate is weighed to generate a smaller ruthenium cluster anchored vanadium disulfide composite carbon cloth self-supporting electrode.

[0069] Example 3

[0070] In this Example 3, the preparation method of the carbon-based self-supporting electrode is the same as in Example 1, except that: the content of ruthenium source is increased to keep its loading at 5 wt%, and 8 mg of ruthenium chloride trihydrate is weighed to generate a larger ruthenium cluster anchored vanadium disulfide composite carbon cloth self-supporting electrode.

[0071] Example 4

[0072] The preparation method of the carbon-based self-supporting electrode in Example 4 is the same as that in Example 1, except that the concentration of the precursor solution is diluted to 1 mol / L, and the ruthenium cluster-anchored vanadium disulfide composite carbon cloth self-supporting electrode is also obtained.

[0073] Example 5

[0074] The preparation method of the carbon-based self-supporting electrode in Example 5 is the same as that in Example 1, except that the concentration of the precursor solution is increased to 10 mol / L, and the ruthenium cluster-anchored vanadium disulfide composite carbon cloth self-supporting electrode is also obtained.

[0075] Example 6

[0076] The preparation method of the carbon-based self-supporting electrode in Example 6 is the same as that in Example 1, except that the heating temperature in step (3) is 180°C and the holding time is 18h, thus obtaining a smaller ruthenium cluster anchored vanadium disulfide composite carbon cloth self-supporting electrode.

[0077] Example 7

[0078] The preparation method of the carbon-based self-supporting electrode in Example 7 is the same as that in Example 1, except that the heating temperature in step (3) is 240°C and the holding time is 30h, and the ruthenium cluster anchored vanadium disulfide composite carbon cloth self-supporting electrode is also obtained.

[0079] Comparative Example 1

[0080] It uses simple commercial carbon cloth, and its surface is not loaded with any active substances.

[0081] Figure 3 The X-ray diffraction patterns of the vanadium disulfide-supported ruthenium cluster composite carbon cloth in Example 1 and the pure carbon cloth in Comparative Example 1 are shown. It can be seen from the figure that the prominent characteristic peaks belong to vanadium disulfide and ruthenium, respectively, while the pattern of the pure carbon cloth only shows the typical characteristic peaks of carbon.

[0082] Figure 10 This is a scanning electron microscope image of pure carbon cloth. The image shows a smooth, clean carbon fiber surface without any excess material, which is consistent with... Figure 1 The reaction resulted in the growth of dense vanadium disulfide nanosheets, creating a striking contrast.

[0083] Figure 11 The graph shows the cycle life of the vanadium disulfide-supported ruthenium cluster composite carbon cloth from Example 1 and the pure carbon cloth from Comparative Example 1, used as the air cathode in a zinc-air battery. The graph shows that the pure carbon cloth exhibits severe voltage decay after only 8 hours of cycling, while the vanadium disulfide-supported ruthenium cluster composite carbon cloth can operate stably for over 470 hours without significant voltage fluctuations, and its overpotential is also much lower than that of the pure carbon cloth. This result confirms that the electrochemically encapsulated ruthenium cluster-anchored vanadium disulfide nanosheet composite carbon cloth significantly improves catalytic activity and durability, while reducing the polarization voltage during battery charging and discharging, achieving a long-lasting and stable cycle life.

[0084] Comparative Example 2

[0085] In Comparative Example 2, the preparation method of the carbon-based self-supporting electrode was the same as in Example 1, except that the content of the ruthenium source was reduced to maintain its loading at 0.4 wt%, and 0.5 mg of ruthenium chloride trihydrate was weighed. No ruthenium clusters were observed anchoring the vanadium disulfide composite carbon cloth self-supporting electrode; only vanadium disulfide nanosheets composite carbon cloth were observed. Figure 12 As shown.

[0086] Comparative Example 3

[0087] The preparation method of the carbon-based self-supporting electrode in Comparative Example 3 is the same as that in Example 1, except that the content of the ruthenium source is increased to maintain its loading at 6 wt%, and 10 mg of ruthenium chloride trihydrate is weighed out. Large-sized ruthenium particle aggregates are generated and adhere to the surface of the vanadium disulfide nanosheet composite carbon cloth self-supporting electrode. Figure 13 As shown.

[0088] Comparative Example 4

[0089] The preparation method of the carbon-based self-supporting electrode in Comparative Example 4 is the same as that in Example 1, except that the heating temperature in step (3) is 170°C and the holding time is 17h, which makes it impossible to obtain pure phase VS2@CC and Ru clusters. Figure 14 As shown.

[0090] Comparative Example 5

[0091] The preparation method of the carbon-based self-supporting electrode in Comparative Example 5 is the same as that in Example 1, except that the heating temperature in step (3) is 170°C and the holding time is 32h. Similarly, pure-phase VS2@CC and Ru clusters cannot be obtained. Figure 15 As shown.

[0092] Comparative Example 6

[0093] The preparation method of the carbon-based self-supporting electrode in Comparative Example 6 is the same as that in Example 1, except that the heating temperature in step (3) is 250°C and the holding time is 17h. This allows for the deposition of non-pure phase VS2 particles on the carbon fiber skeleton, but Ru clusters are not observed. Figure 16 As shown.

[0094] Comparative Example 7

[0095] The preparation method of the carbon-based self-supporting electrode in Comparative Example 7 is the same as that in Example 1, except that the heating temperature in step (3) is 250°C and the holding time is 32h. Only the broken non-pure phase VS2 flocculent material is observed adhering to the carbon fiber skeleton, and Ru clusters are not observed. Figure 17 As shown.

Claims

1. A method for preparing a carbon-based self-supporting electrode, characterized in that, The carbon-based self-supporting electrode comprises a carbon cloth and vanadium disulfide nanosheets loaded with metal ruthenium clusters grown in situ on the carbon cloth. The preparation method of the carbon-based self-supporting electrode comprises the following steps: (1) Preparation of a precursor solution: vanadium source, sulfur source and ruthenium source are weighed and dispersed in deionized water to form a precursor solution; the mass ratio of the vanadium source, sulfur source and ruthenium source is 15-20:10-20:1-3; (2) Treatment of the carbon cloth: cut carbon cloth is placed in a concentrated nitric acid solution and stirred, and then washed with deionized water and anhydrous ethanol and dried; (3) The precursor solution is transferred to a polytetrafluoroethylene-lined stainless steel high-pressure reaction kettle, and the carbon cloth is vertically placed in the reaction kettle as a base material, heated and kept warm, and after the reaction kettle is cooled to room temperature, the sample is taken out, washed with deionized water and anhydrous ethanol in turn, and then dried; the heating temperature is 180-240°C, and the holding time is 18-30 hours.

2. The method for preparing a carbon-based self-supporting electrode according to claim 1, characterized by, The particle size of the metal ruthenium clusters is 1-10 nm; based on 100wt% of the vanadium disulfide nanosheets loaded with metal ruthenium clusters, the loading amount of the metal ruthenium clusters is 1-5wt%.

3. The method for preparing a carbon-based self-supporting electrode according to claim 1 or 2, characterized in that, The size of the vanadium disulfide nanosheets loaded with metal ruthenium clusters is 50-100nm×40-80nm×3-6nm; based on 100wt% of the carbon-based self-supporting electrode, the content of the vanadium disulfide nanosheets loaded with metal ruthenium clusters is 40-80wt%.

4. The method of claim 1, wherein the carbon-based self-supporting electrode is prepared by a process comprising: In the step (1), the vanadium source is sodium vanadate, the sulfur source is thioacetamide, and the ruthenium source is ruthenium chloride trihydrate.

5. The method for preparing a carbon-based self-supporting electrode according to claim 1, characterized by, In the step (1), the concentration of vanadium ions in the precursor solution is 1-10 mol / L.

6. The method of claim 1, wherein the carbon-based self-supporting electrode is prepared by a process comprising: In the step (2), the size of the cut carbon cloth is 1-3cm×1-3cm; the concentration of the concentrated nitric acid is 8-16mol / L.

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