A ruthenium-based three-dimensional hollow cross-linked composite catalyst, a preparation method and application thereof

Abstract

The application discloses a ruthenium-based three-dimensional hollow cross-linked composite catalyst and a preparation method and application thereof. The preparation method comprises the following steps: S1, completely immersing melamine foam in an aqueous solution of carbon nitride precursor, and sequentially performing drying and calcination to obtain a carbon nitride base material; S2, completely immersing the carbon nitride base material in an aqueous solution of metal salt, and sequentially performing drying and calcination to load metal, so as to obtain a solid material; the metal salt comprises a metal salt of ruthenium; S3, removing metal impurities in the solid material, and then performing drying to obtain the ruthenium-based three-dimensional hollow cross-linked composite catalyst. The melamine foam is carbonized to generate nitrogen-doped carbon foam, and through impregnation concentration and calcination parameters in a specific range, the product is promoted to grow into a single-metal Ru or a Ru-based bimetallic electrocatalyst containing a transition metal, and the preparation process is simple and easy to implement; the optimal overpotential of the obtained material is as low as 44 mV, and the Tafel slope is as low as 68 mV / dec.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic hydrogen evolution technology, and in particular to a ruthenium-based three-dimensional hollow crosslinked composite catalyst, its preparation method, and its application. Background Technology

[0002] As the global energy mix shifts from fossil fuels to renewable energy, the exploration of renewable and clean energy sources is urgently needed. Hydrogen, the lightest and most abundant element known in the universe, is receiving unprecedented attention due to its high calorific value, low pollution, wide availability, and flexible conversion capabilities. In recent years, my country has made breakthroughs in hydrogen production, storage, transportation, and utilization technologies, and hydrogen energy is expected to become one of the mainstays of the future low-carbon energy system.

[0003] The utilization of hydrogen energy begins with hydrogen production. Since hydrogen rarely exists in nature in its elemental form, it must be produced through industrial processes. Hydrogen sources include coal-to-hydrogen, natural gas-to-hydrogen, methanol cracking-to-hydrogen, and water electrolysis-to-hydrogen. The first three methods all produce carbon dioxide emissions. However, water electrolysis-to-hydrogen technology uses safe, readily available, and renewable water as a raw material, with pure oxygen as the only byproduct. Furthermore, under current technological conditions, water electrolysis-to-hydrogen technology can produce hydrogen with an initial purity of 99.8%, which can be further purified to 99.999%, making it the most ideal hydrogen source.

[0004] The efficiency of hydrogen production and storage through water electrolysis largely depends on the hydrogen evolution reaction (HER), and platinum group metals are the most effective catalysts for HER. To date, numerous studies have confirmed that platinum (Pt)-based materials exhibit the best HER performance. However, their low availability and high cost on Earth hinder their large-scale application. Therefore, developing highly active, highly stable, and inexpensive catalysts remains a significant challenge. The Sabatier principle states that the hydrogen adsorption free energy (ΔG) on the catalyst surface... H* The rate of HER has a significant impact. The ΔG of Ru H* Similar to Pt but at only one-third the price, Ru-based catalysts exhibit superior H-OH bond breaking ability compared to Pt-based catalysts. Therefore, Ru-based materials are a promising alternative to Pt-based catalysts. Furthermore, abundant and inexpensive transition metal catalysts also hold promise as alternatives to Pt-based catalysts. However, the poor electrical conductivity and inherent activity of Ru-based materials limit their application in electrocatalysis. Combining transition metals with noble metals to form bimetallic catalysts can not only reduce the amount of noble metal used and lower costs, but also, through bimetallic synergy, alter their structure and electronic properties, thereby enhancing catalytic activity.

[0005] However, in most cases, the surface free energy of nanoparticles formed by metal catalysts is high, making them prone to aggregation and hindering the exposure of active sites. A good support not only has a high surface area to disperse metal nanoparticles but also a strong affinity for them, effectively preventing their migration or leaching during the reaction. Carbon nitride exhibits high thermal stability; metal nanoparticles, after interacting with carbon nitride, are fixed at the adsorption sites on the carbon nitride and remain stable at high temperatures. However, carbon nitride materials prepared by direct polycondensation of precursors such as dicyandiamide or melamine typically have a lower surface area. Summary of the Invention

[0006] To overcome the problem of nanoparticle aggregation during the synthesis of single-metal Ru and Ru-based bimetallic electrocatalysts containing transition metals in existing technologies, this invention provides a ruthenium-based three-dimensional hollow crosslinked composite catalyst, its preparation method, and its application. This ruthenium-based three-dimensional hollow crosslinked composite catalyst can be a single-metal Ru or a Ru-based bimetallic catalyst containing transition metals supported on a three-dimensional hollow crosslinked carbon nitride electrocatalyst. During preparation, melamine foam is used as a template. The substrate of the prepared ruthenium-based three-dimensional hollow crosslinked composite catalyst is a carbon nitride substrate with a high specific surface area and a three-dimensional hollow crosslinked structure, which enhances the dispersibility of metal nanoparticles. The resulting material has a high catalytic surface area and good mass transport efficiency, exhibiting excellent electrocatalytic hydrogen evolution performance.

[0007] The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst provided by the present invention includes the following steps:

[0008] S1. Melamine foam is completely immersed in an aqueous solution of carbon nitride precursor, and then dried and calcined in sequence to obtain carbon nitride substrate material.

[0009] S2. The carbon nitride substrate material is completely immersed in an aqueous solution of a metal salt, and then dried and calcined sequentially to load the metal, thereby obtaining a solid material; the metal salt includes a ruthenium metal salt.

[0010] S3. Remove the metallic impurities from the solid material and then dry it to obtain the ruthenium-based three-dimensional hollow crosslinked composite catalyst.

[0011] The preparation method of this invention uses melamine foam as a template to generate nitrogen-doped carbon foam by carbonizing melamine foam. Nitrogen doping activates the surrounding carbon atoms, which is conducive to the formation of reaction intermediates. The nitrogen-doped carbon generated by carbonization still maintains the original interwoven structure of melamine foam. Within this structural framework, melamine deposited on its surface is further thermally polymerized to generate a stable three-dimensional hollow cross-linked carbon nitride substrate with a high specific surface area. Further pyrolysis with metal yields a three-dimensional metal-supported nitrogen-carbon material with high catalytic surface area and good mass transport efficiency.

[0012] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the carbon nitride precursor can be selected from any one of cyanamide, dicyandiamide, urea, melamine and thiourea.

[0013] The aqueous solution of the carbon nitride precursor is a saturated concentration solution, such as a solution prepared by adding 0.6g of melamine powder to 100g of water at a temperature of 35°C. When the melamine concentration is lower than the saturated concentration, the carbon nitride generated by pyrolysis cannot provide more metal attachment sites. When the melamine concentration is higher than the saturated concentration, the carbon nitride accumulates, making the substrate structure more disordered.

[0014] The size of the melamine foam is not limited, as long as it can be completely immersed in the aqueous solution of the carbon nitride precursor. For example, each 20*30*50mm melamine foam can be completely immersed in 20mL of the aqueous solution of the carbon nitride precursor.

[0015] The melamine foam is commercially available melamine foam. Commercially available melamine foams mainly include melamine-formaldehyde foam and melamine foam. Considering the impact of impurities on catalyst performance, this invention selects foam containing only melamine. In a specific embodiment of this invention, the density of the melamine foam is 8.5–9 kg / m³. 3 .

[0016] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the drying in step S1 is freeze drying to maintain its three-dimensional structure;

[0017] The calcination described in step S1 can be carried out under a nitrogen or argon atmosphere;

[0018] The heating rate of calcination in step S1 can be 3 to 5 °C / min, specifically 5 °C / min;

[0019] The calcination temperature in step S1 can be 500–800℃, such as 600℃, and the calcination time can be 2–4 hours, such as 3 hours. The calcination process allows melamine to fully pyrolyze and generate carbon nitride, and a suitable calcination temperature is beneficial for effective carbonization.

[0020] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the metal salt is a ruthenium metal salt (single metal salt) or is composed of a ruthenium metal salt and other transition metal metal salts;

[0021] Furthermore, the other transition metal salts may be cobalt salts, nickel salts, molybdenum salts, iron salts, manganese salts, or copper salts.

[0022] Further, the ruthenium metal salt or the metal salt of the other transition metals can be its water-soluble salt, such as a chloride salt; in a specific embodiment of the present invention, the ruthenium metal salt is ruthenium trichloride, and it is understood that the ruthenium metal salt can be added in the form of its hydrate, such as ruthenium trichloride trihydrate; in a specific embodiment of the present invention, the cobalt metal salt is cobalt chloride, and it is understood that the cobalt metal salt can be added in the form of its hydrate, such as cobalt chloride hexahydrate; in a specific embodiment of the present invention, the nickel metal salt is anhydrous nickel chloride; in a specific embodiment of the present invention, the molybdenum metal salt is molybdenum pentachloride; in a specific embodiment of the present invention, the iron metal salt is ferric chloride, and it is understood that the iron metal salt can be added in the form of its hydrate, such as ferric chloride hexahydrate; in a specific embodiment of the present invention, the manganese metal salt is manganese chloride; in a specific embodiment of the present invention, the copper metal salt is copper chloride.

[0023] The total concentration of the metal salt in the aqueous solution of the metal salt can be 0.001 g / mL to 0.015 g / mL, such as 0.001 g / mL to 0.005 g / mL, 0.001 g / mL, 0.005 g / mL, 0.010 g / mL or 0.015 g / mL;

[0024] When the metal salt is composed of ruthenium metal salt and other transition metal metal salts, the mass ratio of the ruthenium metal salt to the other transition metal metal salts can be 1:(0.5~2), specifically 1:1, 1:2 or 1:0.5.

[0025] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the drying in step S2 can be freeze-drying to maintain its three-dimensional structure;

[0026] The calcination described in step S2 can be carried out under a nitrogen or argon atmosphere;

[0027] The heating rate of calcination in step S2 can be 3 to 5 °C / min, specifically 5 °C / min;

[0028] The calcination temperature in step S2 can be 700–900℃, such as 800℃, 700℃, or 900℃, and the calcination time can be 2–4 hours, such as 2 hours. This calcination process allows the metal ions to react fully with the substrate material. Too low a temperature is not conducive to metal reduction and bonding with the substrate, while too high a temperature will cause the metal particles to aggregate.

[0029] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the step of removing metallic impurities from the solid material is as follows: immersing the solid material in an aqueous solution of acid;

[0030] In a specific embodiment of the present invention, the solid material is immersed in an aqueous solution of 1 mol / L hydrochloric acid;

[0031] The method further includes washing the solid material after removing metal impurities with water until it is neutral before drying in step S3.

[0032] In the above-mentioned method for preparing ruthenium-based three-dimensional hollow crosslinked composite catalyst, the drying in step S3 can be freeze-drying to maintain its three-dimensional structure.

[0033] The present invention further provides a ruthenium-based three-dimensional hollow crosslinked composite catalyst prepared by any of the above preparation methods.

[0034] The present invention also provides the application of the ruthenium-based three-dimensional hollow crosslinked composite catalyst in electrocatalytic hydrogen evolution.

[0035] The ruthenium-based three-dimensional hollow crosslinked composite catalyst has a unique three-dimensional hollow interwoven structure that provides a large specific surface area, which is conducive to exposing more active sites. As a result, the prepared electrocatalyst has good performance, and the metal particles in the material are uniformly dispersed. The optimal overpotential is as low as 44 mV and the Tafel slope is as low as 68 mV / dec.

[0036] In the above applications, the working electrode in the electrocatalytic hydrogen evolution can be composed of a bare electrode and the ruthenium-based three-dimensional hollow cross-linked composite catalyst and Nafion sequentially modified on the bare electrode. Specifically, it can be prepared by the following steps: the dispersion of the ultrasonically dispersed ruthenium-based three-dimensional hollow cross-linked composite catalyst is dropped onto the bare electrode and allowed to air dry naturally, and then Nafion solution is dropped on it. After drying, the working electrode is obtained.

[0037] Furthermore, the dispersion of the ultrasonically dispersed ruthenium-based three-dimensional hollow crosslinked composite catalyst is composed of ruthenium-based three-dimensional hollow crosslinked composite catalyst, deionized water, and ethanol in a ratio of 0.005 g: 600 μL: 400 μL.

[0038] Furthermore, the drying process is natural air drying;

[0039] In the electrocatalytic hydrogen evolution process, the electrolyte is 1 mol / L KOH;

[0040] In the electrocatalytic hydrogen evolution process, the reference electrode is silver chloride and the counter electrode is platinum wire;

[0041] The electrocatalytic hydrogen evolution performance was tested by linear voltammetry scanning, with a scan potential ranging from -0.9V to -1.6V and a scan rate of 0.005V / s.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] This invention provides a method for preparing a ruthenium-based three-dimensional hollow crosslinked composite catalyst. Using melamine foam as a template, the melamine foam is completely immersed in a carbon nitride precursor solution. The melamine foam is carbonized to generate nitrogen-doped carbon foam, which is then further mixed with a metal and pyrolyzed to obtain a three-dimensional metal-supported nitrogen-carbon material. By controlling the impregnation concentration and calcination parameters within a specific range, the product is promoted to grow into a single-metal Ru and a Ru-based bimetallic electrocatalyst containing a transition metal. This method has the advantages of being simple and easy to implement. The obtained material exhibits an optimal overpotential as low as 44 mV and a Tafel slope as low as 68 mV / dec, demonstrating high catalytic activity and suitable for electrocatalytic hydrogen evolution. Attached Figure Description

[0044] Figure 1 This is a flowchart illustrating the preparation method of ruthenium-based three-dimensional hollow crosslinked composite catalyst in a specific embodiment of the present invention.

[0045] Figure 2 This is an element scan diagram of Embodiment 4 of the present invention.

[0046] Figure 3 This is a polarization curve of Comparative Example 1, Example 1 and Example 4 of the present invention in 1 mol / L KOH electrolyte. Detailed Implementation

[0047] To provide a deeper understanding of this invention, specific examples are provided below to further illustrate it. It should be noted that the following embodiments are only a portion of the embodiments of this invention and should not be construed as limiting the scope of protection of this invention. Furthermore, non-essential improvements and adjustments made by those skilled in the art based on the content of this invention still fall within the scope of protection of this invention.

[0048] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; and the materials and reagents used are commercially available unless otherwise specified.

[0049] The melamine foam used in the following examples was produced by Shanghai Beiyou Building Materials Co., Ltd., with a density of 8.5–9 kg / m³. 3 Products.

[0050] Example 1: Preparation of Ru-gCNMS electrocatalyst Al-800

[0051] according to Figure 1 The flowchart shown illustrates the preparation of a ruthenium-based three-dimensional hollow crosslinked composite catalyst. The specific steps are as follows:

[0052] (1) Commercially available melamine foam was cut into rectangular blocks of 20*30*50mm in size, cleaned and dried, and then completely immersed in a saturated melamine solution (0.066g of melamine was added to 20mL of water). After freeze-drying, it was calcined in a tube furnace with nitrogen gas at 5℃ / min to 600℃ for 3h to obtain the base material.

[0053] (2) The substrate material was completely immersed in a 0.001 g / mL metal salt solution (0.02 g of ruthenium trichloride trihydrate was added to 20 mL of deionized water), freeze-dried, and then calcined in a tube furnace with nitrogen gas at 5 °C / min to 800 °C for 2 h to obtain a solid material.

[0054] (3) The solid material was soaked in 1 mol / L hydrochloric acid to remove impurities, then washed with deionized water until neutral, and freeze-dried to obtain Ru-gCNMS electrocatalyst Al-800.

[0055] Example 2

[0056] In this embodiment, the Ru-gCNMS electrocatalyst was prepared using a method similar to that in Example 1, except that step (2) was changed to heating to 700°C. The remaining steps were the same as in Example 1, resulting in Ru-gCNMS electrocatalyst Al-700.

[0057] Example 3

[0058] In this embodiment, the Ru-gCNMS electrocatalyst was prepared using a method similar to that in Example 1, except that step (2) was changed to heating to 900°C. The remaining steps were the same as in Example 1, resulting in the Ru-gCNMS electrocatalyst Al-900.

[0059] Example 4

[0060] In this embodiment, the Ru-gCNMS electrocatalyst was prepared using a method similar to that in Example 1. The difference from Example 1 is that step (2) was changed to adding 0.1 g of ruthenium trichloride trihydrate to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps were the same as in Example 1, resulting in Ru-gCNMS electrocatalyst A2-800.

[0061] Elemental scan of Ru-gCNMS electrocatalyst A2-800 is shown below. Figure 2 ,from Figure 2 The Ru-gCNMS electrocatalyst exhibits a three-dimensional hollow interwoven structure, with metal particles of average size 3.96 nm uniformly distributed on the substrate surface.

[0062] Example 5

[0063] This embodiment prepares the CoRu-gCNMS electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (2) is changed to adding 0.05 g of ruthenium trichloride trihydrate and 0.05 g of cobalt chloride hexahydrate to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps are the same as in Example 1, yielding the CoRu-gCNMS electrocatalyst B2-800.

[0064] Example 6

[0065] This embodiment prepares the NiRu-gCNMS electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (2) is changed to adding 0.05 g of ruthenium trichloride trihydrate and 0.05 g of anhydrous nickel chloride to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps are the same as in Example 1, yielding the NiRu-gCNMS electrocatalyst C2-800.

[0066] Example 7

[0067] This embodiment prepares the MoRu-gCNMS electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (2) is changed to adding 0.05 g of ruthenium trichloride trihydrate and 0.05 g of molybdenum pentachloride to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps are the same as in Example 1, resulting in MoRu-gCNMS electrocatalyst D2-800.

[0068] Example 8

[0069] This embodiment prepares the FeRu-gCNMS electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (2) is changed to adding 0.05 g of ruthenium trichloride trihydrate and 0.05 g of ferric chloride hexahydrate to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps are the same as in Example 1, yielding the FeRu-gCNMS electrocatalyst E2-800.

[0070] Example 9

[0071] In this embodiment, the MnRu-gCNMS electrocatalyst was prepared using a method similar to that in Example 1. The difference from Example 1 is that step (2) was changed to adding 0.05 g of ruthenium trichloride trihydrate and 0.05 g of manganese chloride to 20 mL of deionized water to prepare a 0.005 g / mL metal salt solution. The remaining steps were the same as in Example 1, resulting in the MnRu-gCNMS electrocatalyst F2-800.

[0072] Example 10

[0073] This embodiment prepares the CuRu-gCNMS electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (2) is changed to adding 0.05g of ruthenium trichloride trihydrate and 0.05g of copper chloride to 20mL of deionized water to prepare a 0.005g / mL metal salt solution. The remaining steps are the same as in Example 1, resulting in CuRu-gCNMS electrocatalyst G2-800.

[0074] Comparative Example 1

[0075] Commercial 20% Pt / C catalyst (Beijing Bailingwei Technology Co., Ltd.)

[0076] Comparative Example 2

[0077] This embodiment prepares the Ru-gCN electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (1) directly uses melamine for polycondensation to prepare the carbon nitride substrate. The specific steps are as follows: 0.066g of melamine is added to 20mL of water, freeze-dried, and then calcined in a tube furnace under nitrogen atmosphere at 5℃ / min to 600℃ for 3h to obtain the substrate material. The above substrate material and 0.02g of ruthenium trichloride trihydrate are added to 20mL of deionized water, freeze-dried, and then calcined in a tube furnace under nitrogen atmosphere at 5℃ / min to 800℃ for 2h to obtain a solid material. The remaining steps are the same as in Example 1, yielding the Ru-gCN electrocatalyst A2-800.

[0078] Comparative Example 3

[0079] This embodiment prepares a three-dimensional Ru-gCN electrocatalyst using a method similar to that of Example 1. The difference from Example 1 is that step (1) involves the polycondensation of melamine and calcium carbonate to prepare the three-dimensional carbon nitride substrate. The specific steps are as follows: 0.066 g of melamine and 0.066 g of calcium carbonate are added to 20 mL of water, freeze-dried, and then calcined in a tube furnace under nitrogen atmosphere at a temperature of 5 °C / min to 600 °C for 3 h. The calcium carbonate is washed with 1 mol / L hydrochloric acid and then washed with water until neutral to obtain the substrate material. The above substrate material and 0.02 g of ruthenium trichloride trihydrate are added to 20 mL of deionized water, freeze-dried, and then calcined in a tube furnace under nitrogen atmosphere at a temperature of 5 °C / min to 800 °C for 2 h to obtain a solid material. The remaining steps are the same as in Example 1, yielding Ru-gCN electrocatalyst A3-800.

[0080] Electrochemical performance testing: 0.005 g of the electrocatalyst prepared by the above method was ultrasonically dispersed in 600 μL of deionized water and 400 μL of ethanol. 10 μL of the dispersion was dropped onto a glassy carbon working electrode and allowed to air dry. Then, 5 μL of 5 wt% Nafion solution was added, and after air drying, it was ready for electrochemical performance testing. The workstation used for performance testing was a CHI760E (purchased from Shanghai Chenhua Instrument Co., Ltd.). The electrolyte was 1 mol / L KOH, the reference electrode was silver chloride, and the counter electrode was platinum wire. In the test, cyclic voltammetry (scanning potential from -0.9 V to -1.6 V, scan rate 0.1 V / s) was first run for 40 cycles to stabilize the catalyst performance. Then, linear voltammetry was performed (scanning potential from -0.9 V to -1.6 V, scan rate 0.005 V / s).

[0081] All overpotentials in this work are converted to a standard hydrogen electrode (RHE), using the conversion formula E. (RHE) =E (Ag / AgCl) +0.197 + 0.0592 * pH, ultimately choosing 10 mA / cm 2 Performance is compared using the overpotential corresponding to the current density.

[0082] The comparison results of the electrochemical performance of each embodiment and the comparative example are shown in Table 1:

[0083] Table 1. Electrochemical performance results

[0084] Comparative Example 1 28 51 Comparative Example 2 364 272 Comparative Example 3 196 225 A1-800 140 143 A1-700 172 156 A1-900 165 149 A2-800 44 68 B2-800 57 72 C2-800 90 98 D2-800 79 87 E2-800 123 110 F2-800 160 151 G2-800 231 199

[0085] The polarization curves of Comparative Example 1, Example 1, and Example 4 in 1 mol / L KOH electrolyte are shown below. Figure 3 Through Table 1 and Figure 3 The results show that the electrocatalyst prepared by the method of the present invention has high catalytic activity.

[0086] The embodiments described above are not intended to limit the scope of the present invention, but rather to describe preferred implementation methods of the present invention. Various improvements and modifications made by other skilled personnel in the art to the technical solutions of the present invention should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a ruthenium-based three-dimensional hollow crosslinked composite catalyst for electrocatalytic hydrogen evolution, comprising the following steps: S1. Melamine foam is completely immersed in an aqueous solution of carbon nitride precursor, and then dried and calcined in sequence to obtain carbon nitride substrate material. The carbon nitride precursor is selected from any one of cyanamide, dicyandiamide, urea, melamine, and thiourea; The aqueous solution of the carbon nitride precursor is a saturated concentration solution; S2. The carbon nitride substrate material is completely immersed in an aqueous solution of a metal salt, and then dried and calcined sequentially to load the metal, thereby obtaining a solid material; the metal salt includes a ruthenium metal salt. S3. Remove the metallic impurities from the solid material and then dry it to obtain the ruthenium-based three-dimensional hollow crosslinked composite catalyst; The steps for removing metallic impurities from the solid material are as follows: immersing the solid material in an aqueous solution of acid.

2. The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 1, characterized in that: The drying process described in step S1 is freeze drying; The calcination described in step S1 is carried out under a nitrogen or argon atmosphere; The heating rate for calcination in step S1 is 3~5℃ / min; The calcination temperature in step S1 is 500~800℃, and the calcination time is 2~4h.

3. The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 1 or 2, characterized in that: The metal salt is a ruthenium metal salt or is composed of a ruthenium metal salt and metal salts of other transition metals; The other transition metal salts are cobalt salts, nickel salts, molybdenum salts, iron salts, manganese salts, or copper salts. The total concentration of the metal salt in the aqueous solution is 0.001 g / mL to 0.015 g / mL; When the metal salt is composed of ruthenium metal salt and other transition metal metal salts, the mass ratio of the ruthenium metal salt to the other transition metal metal salts is 1:(0.5~2).

4. The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 1 or 2, characterized in that: The drying process described in step S2 is freeze drying; The calcination described in step S2 is carried out under a nitrogen or argon atmosphere; The heating rate for calcination in step S2 is 3~5℃ / min; The calcination temperature in step S2 is 700~900℃, and the calcination time is 2~4h.

5. The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 1 or 2, characterized in that: The method further includes washing the solid material after removing metal impurities with water until it is neutral before drying in step S3.

6. The method for preparing the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 1 or 2, characterized in that: The drying process described in step S3 is freeze drying.

7. The ruthenium-based three-dimensional hollow crosslinked composite catalyst prepared by the preparation method according to any one of claims 1-6.

8. The application of the ruthenium-based three-dimensional hollow crosslinked composite catalyst according to claim 7 in electrocatalytic hydrogen evolution.

9. The application according to claim 8, characterized in that: In the electrocatalytic hydrogen evolution process, the working electrode consists of a bare electrode and the ruthenium-based three-dimensional hollow crosslinked composite catalyst and Nafion as described in claim 7, which are sequentially modified onto the bare electrode.

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