Alkaline electrolytic water hydrogen evolution supported Ru3 cluster catalyst with accurate atom number and preparation method thereof

Abstract

The invention discloses a supported Ru3 cluster catalyst with accurate atom number for hydrogen evolution from alkaline electrolysis water and a preparation method thereof, and belongs to the technical field of catalyst materials. The Ru3 cluster is loaded on a carrier oxidized carbon nanotube to obtain the alkaline water electrolysis hydrogen evolution loaded Ru3 cluster catalyst with accurate atom number, and the loading capacity of Ru is 0.8-4.3 wt%. The catalyst has good hydrogen evolution reaction catalytic activity under the alkaline condition, the utilization efficiency of Ru atoms is high, and the structure of the catalyst is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst materials, and in particular relates to an alkaline water electrolysis hydrogen evolution supported type Ru3 cluster catalyst with precise atomic number and a preparation method thereof. Background Art

[0002] In recent years, hydrogen energy, as a clean, zero-carbon, flexible and efficient secondary energy source, has attracted much attention from researchers and is considered one of the important ways to solve the current energy crisis and environmental problems. Compared with traditional fossil energy, hydrogen energy has many advantages. It not only has zero emissions in the process of energy production and utilization, but also can achieve efficient utilization and reduce negative impacts on the environment.

[0003] Among the many hydrogen production methods, alkaline water electrolysis is considered to be one of the important ways to promote the development of sustainable energy due to its safety, stability and high purity. With the increasing demand for clean energy, the further development and application of alkaline water electrolysis hydrogen production technology will play a more important role in the future. Precious metal catalysts are usually used to reduce the overpotential and energy consumption of the hydrogen evolution reaction (HER). So far, the most effective HER catalysts are still platinum and platinum-based metals. Theoretical studies have shown that the key factor determining the conversion efficiency and stability of the electrolyte is the adsorption energy of the electrocatalyst. For platinum, the adsorption energy of adsorbed hydrogen is close to zero at the equilibrium potential and has the highest exchange current density, which gives it excellent HER performance. But in fact, the kinetic reaction rate of Pt-based catalyst HER under alkaline conditions is 2 orders of magnitude lower than that under acidic conditions, which is one of the slow kinetic problems that HER needs to overcome under alkaline conditions. Moreover, platinum is rare and expensive, which greatly hinders their widespread application. Highly active catalysts can accelerate the hydrogen evolution reaction, increase the hydrogen yield and output, and thus reduce the cost of hydrogen production. Low cost is one of the necessary conditions for large-scale industrial hydrogen production, because cost reduction will make clean hydrogen more competitive and help promote the widespread application of clean energy. In addition, highly stable catalysts can maintain good catalytic activity for a long time, reduce the frequency of catalyst replacement and process downtime, improve the stability and reliability of the hydrogen production process, and reduce production costs. Therefore, the development of HER reaction catalysts with high activity, low cost and high stability is of vital importance for industrial hydrogen production.

[0004] In recent years, ruthenium (Ru) and ruthenium-based nanocatalysts have attracted increasing attention in the field of hydrogen production by water electrolysis due to their electrochemical activity similar to that of platinum. These catalysts have many advantages, including low cost, excellent catalytic performance and good stability, making them strong competitors to replace traditional platinum-based catalysts. In the past few years, Ru has been widely studied as the catalytic active center of alkaline HER, but as a noble metal, if the utilization rate of Ru is not high, the cost of the catalyst will remain high. Therefore, reducing the noble metal loading while maintaining high activity and stability is crucial for the design of high-performance catalysts. Summary of the invention

[0005] In order to solve the defects of low Ru utilization, low catalytic activity and short catalytic life in the supported Ru catalyst used for alkaline electrocatalytic hydrogen evolution reaction in the prior art, the present invention proposes a supported Ru3 cluster catalyst with precise atomic number for alkaline water electrolysis hydrogen evolution and a preparation method thereof. The catalyst has high catalytic activity, stable structure, long service life, and has the characteristics of ultra-low loading and stability in the HER reaction under alkaline conditions. It is a new alkaline HER electrocatalytic material that is expected to be industrialized.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] Technical purpose 1: A supported Ru3 cluster catalyst with precise atomic number for hydrogen evolution in alkaline water electrolysis, wherein the Ru3 cluster is supported on a carrier oxidized carbon nanotube, and the loading amount of Ru is 0.8-4.3wt%.

[0008] Furthermore, the Ru3 cluster has an average particle size of 0.3 nm and is composed of three atoms.

[0009] Technical purpose 2: A method for preparing the alkaline water electrolysis hydrogen evolution supported Ru3 cluster catalyst with precise atomic number, comprising the following steps:

[0010] Adding carbon nanotubes to the mixed acid and ultrasonically shaking, the carbon nanotubes are evenly dispersed and then placed in an oil bath for magnetic stirring, and then cooled to room temperature, washed with deionized water until neutral, dried, and ground to obtain oxidized carbon nanotubes;

[0011] The Ru source precursor is ultrasonically dissolved in a solvent to obtain a Ru source precursor solution, which is dropwise added into a solvent in which the oxidized carbon nanotubes are uniformly dispersed, stirred at room temperature, centrifuged to obtain a black product, and dried;

[0012] The dried black product is placed on a carbon cloth for calcination to obtain a Ru3 cluster catalyst with a precise number of atoms supported on the oxidized carbon nanotubes.

[0013] Furthermore, the mixed acid is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3;

[0014] The temperature of the oil bath was 75° C., and the stirring time in the oil bath was 3 h.

[0015] Furthermore, the Ru source precursor is Ru3(CO) 12 ; The solvent used to prepare the Ru source precursor solution is dichloromethane or tetrahydrofuran, and the concentration of the obtained Ru source precursor solution is 0.2-1 mg / mL;

[0016] The oxidized carbon nanotubes are uniformly dispersed in dichloromethane, and the concentration of the obtained oxidized carbon nanotube solution is 1 mg / mL;

[0017] The stirring time at room temperature is 10-12h.

[0018] Furthermore, the calcination treatment refers to calcination at 350-450° C. for 100-150 seconds under a nitrogen atmosphere.

[0019] Technical purpose three: Application of a Ru3 cluster catalyst with precise atomic number in hydrogen evolution reaction under alkaline conditions.

[0020] Technical purpose four: A method for hydrogen evolution by electrolysis of water, using an alkaline electrolysis of water hydrogen evolution supported Ru3 cluster catalyst with precise atomic number as a catalyst.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] The present invention strictly controls the size of Ru3 clusters, and loads a small amount of Ru3 clusters on oxidized carbon nanotubes with surface oxygen defects, thereby preparing a Ru3 cluster catalyst with a precise number of atoms for hydrogen evolution in alkaline water electrolysis. The catalyst has good alkaline HER electrocatalytic activity, high Ru utilization efficiency, and a stable catalyst structure, and can be applied to hydrogen evolution reaction in alkaline electrolyte. The present invention uses Ru3 clusters as catalytic active centers, significantly improves electrocatalytic HER performance, and has a long-lasting catalytic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 This is a transmission electron microscope (TEM) image of the OCNT catalyst prepared in Example 1;

[0025] Figure 2This is a transmission electron microscopy (TEM) image of the Ru3 / OCNT catalyst prepared in Example 1;

[0026] Figure 3 This is a spherical aberration transmission electron microscopy (AC-TEM) photograph of the Ru3 / OCNT catalyst prepared in Example 1;

[0027] Figure 4 X-ray diffraction patterns (XRD) of the catalysts prepared in Example 1 and Comparative Example 8;

[0028] Figure 5 This is a transmission electron microscopy (TEM) photograph of the catalyst prepared in Comparative Example 2;

[0029] Figure 6 This is a transmission electron microscopy (TEM) photograph of the catalyst prepared in Comparative Example 3;

[0030] Figure 7 This is a transmission electron microscopy (TEM) photograph of the catalyst prepared in Comparative Example 5;

[0031] Figure 8 This is a spherical aberration transmission electron microscopy (AC-TEM) photograph of the catalyst prepared in Comparative Example 8;

[0032] Fig. 9 LSV diagrams of hydrogen evolution reaction of catalysts prepared in Example 1 and Comparative Examples 7, 8, 9 and 10 in 1M KOH solution;

[0033] Fig.10 This is a stability diagram of the catalysts prepared in Example 1 and Comparative Examples 9 and 10 in 1M KOH solution. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] A good solution to the problem of low utilization of ruthenium and ruthenium-based nanocatalysts is to reduce the size of the catalyst to nanoclusters or single atoms to greatly improve the atomic utilization efficiency. However, electrocatalysis is generally considered to be a surface phenomenon, which is highly affected by the surface chemistry of the nanostructure (including the density of active sites on its surface). Therefore, the HER performance of the electrocatalyst can be improved by customizing the active sites. Single-atom catalysts have discrete metal centers, which can theoretically achieve 100% metal utilization, but cannot provide multiple metal atom sites. The adsorption of active intermediates is relatively simple, and it is not suitable for the regulation of multiple adsorptions of H* and OH* at the same time. Metal atom clusters contain a high proportion of surface atoms and have a high atomic utilization rate, which is the first choice for excellent active phases. In addition, the interaction between metal carriers can adjust the surface electronic structure so that the active sites have the best hydrogen adsorption energy, thereby enhancing the catalytic activity for HER. Therefore, the active component can select a metal cluster catalyst. To this end, the present invention uses Ru3 clusters as the catalytic active center of the catalyst to obtain a composite material with high catalytic activity, stable structure and long service life, which is used for HER reaction under alkaline conditions. The specific technical scheme is as follows:

[0040] A Ru3 cluster catalyst with precise atomic number for hydrogen evolution in alkaline water electrolysis, wherein the Ru3 cluster is loaded on a carrier of oxidized carbon nanotubes (OCNT), and the loading amount of Ru is 0.8-4.3wt%. Figure 3 As shown, the average particle size of the Ru3 cluster is 0.3 nm and is composed of three atoms.

[0041] The supported Ru3 cluster catalyst prepared by the present invention has the characteristics of significantly improving the catalytic activity and catalytic stability of alkaline hydrogen evolution. In the prior art, when preparing the supported Ru catalyst, the preparation conditions of continuous high-temperature calcination in an ordinary tubular furnace are generally adopted, which makes the precious metal Ru easily agglomerate to form nanoparticles. It is generally believed that catalysis is a surface reaction, and the clusters are aggregated into particles, which reduces the utilization rate of surface atoms, and the performance will be slightly increased, but the utilization rate of atoms will be seriously reduced, resulting in an increase in cost. The prior art uses a catalyst in a single-atom dispersed state, but it is not suitable for electrolysis of water, that is, it is not suitable for the regulation of multiple adsorptions of H* and OH* at the same time; in addition, the catalytic activity of the single-atom catalyst will decay rapidly, which is not suitable for the technology of industrial electrolysis of water. Therefore, the present invention regulates the size of the nano Ru3 cluster by means of rapid temperature rise and fall calcination regulation in a Joule furnace, load content regulation, etc., so that it does not agglomerate. And it is loaded on an OCNT with surface oxygen defects, and the size structure of the catalyst is characterized by XRD crystal diffraction and electron microscopy technology.

[0042] The preparation method of the alkaline water electrolysis hydrogen evolution supported type Ru3 cluster catalyst with precise atomic number comprises the following steps:

[0043] S1. Preparation of oxidized carbon nanotubes: weigh carbon nanotubes, add them into a mixed acid solution, and use an ultrasonic cleaner to ultrasonically shake them. After the carbon nanotubes are evenly dispersed, magnetic stirring is performed in an oil bath. After the stirring is completed, the mixture is cooled to room temperature, and then centrifuged and washed with deionized water until neutral. The mixture is placed in an oven for drying, and then ground to obtain oxidized carbon nanotubes (OCNT) for later use.

[0044] S2、Ru3(CO) 12 / OCNT synthesis: Take the Ru source precursor and dissolve it in the solvent by ultrasonic, then add it drop by drop into the corresponding solvent in which OCNT is evenly dispersed, stirring while dropping, stirring magnetically for a period of time, centrifuge and wash twice, and put the obtained black product into a vacuum drying oven to dry for later use;

[0045] S3. Ligand pyrolysis: The above black product is placed on a carbon cloth and calcined and reduced by rapidly raising and lowering the temperature in a Joule furnace to obtain a Ru3 catalyst with a precise atomic number loaded on the OCNT.

[0046] In the following preferred embodiment of the present invention, in step S1, the mixed acid is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3;

[0047] The temperature of the oil bath is 75°C, and the stirring time in the oil bath is 3h;

[0048] The drying temperature is 80°C.

[0049] In some preferred embodiments of the present invention, in step S2, the Ru source precursor is Ru3(CO) 12; The solvent used to prepare the Ru source precursor solution is dichloromethane or tetrahydrofuran, and the concentration of the obtained Ru source precursor solution is 0.2-1 mg / mL, preferably 0.3 mg / mL;

[0050] The oxidized carbon nanotubes are uniformly dispersed in dichloromethane, and the concentration of the obtained oxidized carbon nanotube solution is 1 mg / mL;

[0051] The magnetic stirring refers to stirring at room temperature for 10-12 hours, preferably 12 hours. The stirring time should not be too short, otherwise the loading may be incomplete. At this time, it can be judged according to the color of the solution after stirring and centrifugation. If the solution is clear and transparent, it proves that the loading is complete, and if the solution color is slightly yellow, it proves that the loading is incomplete. This step will directly determine the electrochemical HER performance of the synthesized Ru3 clusters.

[0052] In some preferred embodiments of the present invention, in step S3, the rapid heating and cooling is performed using a Joule furnace device: the temperature can be raised to 500-600°C within 1-2 seconds, and then rapidly cooled within 1 second. Using a Joule furnace for calcination can avoid the aggregation of clusters caused by long-term high temperature in an ordinary tubular furnace, and can increase the activity of the catalyst.

[0053] The calcination is to quickly heat up to 350-450°C (preferably 400°C) in a N2 atmosphere in a joule furnace, calcine for 100-150s (preferably 120s) and then quickly cool down to room temperature to obtain the product. In this state, the ligands in the precursor triruthenium dodecacarbonyl are burned off, and the calcination temperature should not be higher, and the calcination time should not be longer, otherwise the Ru3 clusters will further agglomerate to form large particles. The purpose of calcination is to remove the ligands, expose the active sites, and make the clusters more firmly bonded to the carrier, which is beneficial to enhance the activity of the Ru3 clusters while ensuring good stability.

[0054] The alkaline water electrolysis hydrogen evolution supported type Ru3 cluster catalyst with precise atomic number can be applied to hydrogen evolution reaction under alkaline conditions. The supported catalyst based on Ru3 cluster provided by the present invention has high Ru utilization efficiency, high catalytic activity, and the catalyst can remain stable for a long time and has a long service life. It can catalyze hydrogen reduction at room temperature, and the product is non-toxic and harmless, and does not cause secondary pollution.

[0055] A method for hydrogen evolution by electrolysis of water, using an alkaline water electrolysis hydrogen evolution supported Ru3 cluster catalyst with precise atomic number as a catalyst for HER.

[0056] The "room temperature" mentioned in the present invention refers to 25±2°C unless otherwise specified.

[0057] The raw materials used in the present invention are all purchased from the market.

[0058] The technical solution of the present invention is further illustrated by the following embodiments.

[0059] Example 1

[0060] Preparation of supported Ru3 cluster catalysts with precise atomic number for hydrogen evolution in alkaline water electrolysis:

[0061] S1. Preparation of OCNT: Weigh 500 mg of carbon nanotubes and add them into 60 mL of mixed acid solution (volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:3), and use ultrasonic cleaner to ultrasonically vibrate for 5 min. After the carbon nanotubes are evenly dispersed, magnetic stirring is carried out in a 75°C oil bath for 3 h. After the stirring is completed, the mixture is cooled to room temperature, and then centrifuged and washed with deionized water until neutral, and then placed in an oven at 80°C for drying. Grind (grind the blocky OCNT into powder so that it can be evenly dispersed in the solvent later) and set aside.

[0062] S2、Ru3(CO) 12 Synthesis of OCNT: 3 mg of the precursor triruthenium dodecacarbonyl (Ru3(CO) 12 ) was ultrasonically dissolved in 10 mL of dichloromethane, and then added dropwise to 100 mL of dichloromethane in which 100 mg of OCNT was uniformly dispersed, with stirring while dropping. After magnetic stirring for 12 h, the mixture was centrifuged and washed twice at 10,000 rpm. The black product obtained was Ru3(CO) 12 / OCNT, put into vacuum drying oven for later use;

[0063] S3. Ligand pyrolysis: The above black product was placed on a carbon cloth, and the temperature was rapidly raised to 400°C in a Joule furnace. The product was calcined in a N2 atmosphere for 120 seconds, and then rapidly cooled to room temperature to obtain an alkaline water electrolysis hydrogen evolution supported Ru3 cluster catalyst (Ru3 / OCNT catalyst).

[0064] According to the inductively coupled plasma emission spectrometer (ICP) test, the Ru loading in the composite catalyst prepared in Example 1 is 1.287 wt %.

[0065] Figure 1 This is a transmission electron microscope (TEM) image of the oxidized carbon nanotubes prepared in this example. It can be seen from the image that the carrier OCNT has an obvious tubular structure.

[0066] Figure 2 This is a transmission electron microscopy (TEM) image of the Ru3 / OCNT catalyst prepared in this example. It can be observed from the image that, compared with the initial OCNT ( Figure 1 ) similar to MWCNTs, with no visible black spots attributable to Ru nanoparticles.

[0067] Figure 3This is a spherical aberration transmission electron microscopy (AC-TEM) photograph of the Ru3 / OCNT catalyst prepared in this example; it can be seen from the figure that the cluster is composed of 3 atoms, which are evenly dispersed on the carrier OCNT and no agglomeration occurs.

[0068] Figure 4 From the X-ray diffraction pattern (XRD) of the Ru3 / OCNT catalyst prepared in this example, it can be found that there is no characteristic peak corresponding to Ru compared with the standard card, so it is concluded that there are no Ru particles in the catalyst and the Ru3 clusters have not agglomerated.

[0069] Example 2

[0070] Same as Example 1, except that in step S2, the precursor Ru3(CO) 12 The amount added is 2 mg.

[0071] According to the inductively coupled plasma emission spectrometer (ICP) test, the Ru loading in the composite catalyst prepared in this embodiment is 0.843 wt %.

[0072] Example 3

[0073] Same as Example 1, except that in step S2, the precursor Ru3(CO) 12 The amount added was 5 mg.

[0074] According to the inductively coupled plasma emission spectrometer (ICP) test, the Ru loading in the composite catalyst prepared in this embodiment is 2.117 wt %.

[0075] Example 4

[0076] Same as Example 1, except that in step S2, the precursor Ru3(CO) 12 The amount added was 10 mg.

[0077] According to the inductively coupled plasma emission spectrometer (ICP) test, the Ru loading in the composite catalyst prepared in this example is 4.243 wt %.

[0078] Example 5

[0079] Same as Example 1, except that the calcination temperature in step S3 is 350° C. and the calcination time is 100 s.

[0080] Example 6

[0081] Same as Example 1, except that in step S3, the calcination temperature is 450° C. and the calcination time is 150 s.

[0082] Comparative Example 1

[0083] Same as Example 1, except that the calcination temperature in step S3 is 300°C.

[0084] The ligand in this comparative example was not completely removed, and the catalytic performance was poor.

[0085] Comparative Example 2

[0086] Same as Example 1, except that the calcination temperature in step S3 is 500°C.

[0087] Figure 5 This is the TEM image of the catalyst prepared in Comparative Example 2. It can be seen that there are many black spots distributed on the OCNT carrier, indicating that the calcination temperature is too high, causing the average particle size of the Ru3 clusters to reach 1nm, resulting in agglomeration.

[0088] Comparative Example 3

[0089] Same as Example 1, except that the calcination temperature in step S3 is 600°C.

[0090] Figure 6 This is a TEM image of the catalyst prepared in Example 3. It can be seen that the size and density of the black spots distributed on the OCNT carrier are larger than those in Example 3, indicating that the higher the calcination temperature, the more serious the agglomeration of Ru3 clusters (the average particle size of Ru3 clusters is 2 nm).

[0091] Comparative Example 4

[0092] Same as Example 1, except that the calcination time in step S3 is 60s.

[0093] Comparative Example 5

[0094] Same as Example 1, except that the calcination time in step S3 is 180s.

[0095] Figure 7 This is the TEM image of the catalyst obtained in Example 5. It can be seen that some black spots are also distributed on the OCNT carrier, indicating that too long calcination time will also cause the average particle size of the Ru3 clusters to reach 0.7nm, resulting in agglomeration.

[0096] Comparative Example 6

[0097] Same as Example 1, except that in step S2, the precursor Ru3(CO) 12 The amount added was 1 mg.

[0098] According to the inductively coupled plasma emission spectrometer (ICP) test, the Ru loading in the composite catalyst prepared in this embodiment is 0.417 wt % and the average particle size of the Ru3 clusters is 1 nm.

[0099] Comparative Example 7 (Uncertain Number of Atoms)

[0100] Same as Example 1, except that step S3 is not performed, and the Ru3(CO) obtained in step S2 is used. 12 / OCNT directly acts as a catalyst.

[0101] Comparative Example 8 (Single Atom Ru as Load)

[0102] 50 mg of OCNT was dispersed in 20 mL of methanol and ultrasonically treated for 60 min to obtain an OCNT dispersion; RuCl3·3H2O was used as the Ru source, and 250 uL of an aqueous solution containing 0.2 mg of RuCl3·3H2O (the pH of the solution was adjusted to 1 with hydrochloric acid) was added dropwise to the OCNT dispersion, with stirring while dripping. After magnetic stirring at room temperature for 24 h, the solid product was collected by centrifugation, washed twice with a methanol solution, and then dried in a vacuum freeze-drying at 30 ° C. After drying, the powder was heated at 500 ° C for 2 h (heating rate 5 ° C / min) in a tubular furnace under a flowing Ar atmosphere. Finally, the solid product was washed with ultrapure water to remove any impurities to obtain the Ru SAs / OCNT catalyst.

[0103] Figure 4 This is the XRD pattern of the single atom catalyst prepared in Comparative Example 8. As can be seen from the figure, in addition to the typical carbon diffraction peak, there is no diffraction peak of the related Ru metal in the XRD pattern of the Ru single atom.

[0104] Figure 8 This is a spherical aberration transmission electron microscopy (AC-TEM) photograph of the catalyst prepared in Comparative Example 8. From the picture, evenly dispersed single bright spots can be clearly seen, indicating that the Ru single atoms are evenly dispersed on the carrier and no agglomeration occurs.

[0105] Comparative Example 9

[0106] Commercial Pt / C with a mass fraction of 20 wt% was used as the catalyst.

[0107] Comparative Example 10

[0108] Commercial Ru / C with a mass fraction of 5 wt% was used as the catalyst.

[0109] Comparative Example 11

[0110] The same as Example 1, except that step S1 is not performed, and the OCNT in step S2 is replaced by carbon nanotubes. It is found that the solution after loading is darker in color, and the amount of Ru that can be loaded is extremely low.

[0111] Comparative Example 12

[0112] The same as Example 1, except that step S3 is specifically as follows: take the above-mentioned black product and place it on a carbon cloth, heat it to 400°C at a heating rate of 5°C / min in a tubular furnace, calcine it in a N2 atmosphere for 120s, and naturally cool it to room temperature to obtain an alkaline water electrolysis hydrogen evolution supported Ru3 cluster catalyst (Ru3 / OCNT catalyst).

[0113] Application Example 1

[0114] The catalyst performance of the above-mentioned embodiment and comparative example was specifically tested as follows: the test was carried out in a standard three-electrode system, with a carbon rod as the counter electrode, a saturated calomel electrode (SCE) as the reference electrode, and the prepared Ru3 / OCNT (dropped on a hydrophilic carbon paper) as the working electrode. All data were calibrated to the potential relative to the standard hydrogen electrode (RHE), and the electrolyte test results were 85% IR corrected to reduce the impedance of the solution during the test. The test results are shown in Table 1.

[0115] The calibration formula is:

[0116] E (RHE) =E (SCE) +0.0591*pH+0.24-0.85*I*R

[0117] Among them, E (RHE) : potential of the standard hydrogen electrode;

[0118] E (SCE) : potential of saturated calomel electrode;

[0119] I: current density generated during the test;

[0120] R: Impedance during the test.

[0121] Table 1 Catalyst performance preparation

[0122]

[0123] Note: Overpotential η 10 At a current density of 10 mA cm -2 When , the magnitude of the overpotential.

[0124] As can be seen from Table 1, the catalyst prepared by the method of Example 1 has excellent HER performance and stability at room temperature under alkaline conditions; although Example 2 also has excellent performance under the same environment, the amount of Ru added as a precious metal is large and the cost is slightly high; Comparative Examples 1, 2, and 3 verify the effect of calcination temperature on the activity of the catalyst. When the temperature is too low (Comparative Example 1), the ligand is not completely removed and the HER activity is poor; when the temperature is too high (Comparative Examples 2 and 3), Ru3 clusters are prone to agglomeration; Comparative Examples 4 and 5 are the effects of calcination time. When the calcination time of Comparative Example 4 is too short, the ligand is not completely removed and the HER activity is poor. When the calcination time of Comparative Example 5 is too long, the Ru3 clusters are prone to agglomeration; In Example 6, the amount of Ru added is too small, the reaction active sites are few, and the activity of the HER reaction is poor; Comparative Example 7 does not remove the ligand, resulting in poor activity; Comparative Example 8 is a single atom comparative example, and the activity is poor; Comparative Examples 9 and 10 are both commercial catalysts, and the activity and stability of the catalyst prepared in this experiment are better than those of commercial catalysts; Comparative Example 11 is the effect of the carrier on the activity of the catalyst. When the carbon nanotubes are directly used as carriers without acid treatment, the loading of Ru is incomplete and the loading amount is extremely low, resulting in extremely poor activity; Comparative Example 12 is the effect of the heating device. When an ordinary tubular furnace device is used, the nature of the device itself will cause the catalyst to be at high temperature for a long time, resulting in agglomeration of Ru3 clusters.

[0125] Fig. 9 The catalysts prepared in Example 1, Comparative Examples 7, 8, 9, 10, and the OCNT and Ru3(CO) in Example 1 12 LSV diagram of hydrogen evolution reaction of / OCNT in 1M KOH solution; Fig. 9 It can be seen that at 10 mA cm -2 At a current density of , the overpotential of Ru3 / OCNT is only 19 mV, which is better than Pt / C catalyst (26.8 mV), RuC catalyst (43.2 mV) and Ru SAs / OCNT catalyst (176.58 mV).

[0126] Fig.10 The stability diagram of the catalysts prepared in Example 1, Comparative Examples 9 and 10 in 1M KOH solution is shown in FIG. Fig.10 It can be seen that the Ru3 / OCNT catalyst has a -2 The voltage remained almost unchanged after 24 h of electrolysis at a current density of , which is better than that of the commercial Ru / C catalyst and similar to that of the commercial Pt / C catalyst.

[0127] The present invention has innovatively discovered that catalysts made from Ru3 clusters with precise atomic numbers have significantly improved catalytic activity and excellent catalytic effects on HER, while single atoms do not achieve the same excellent catalytic activity. This may be because the unique structure and active sites of Ru3 clusters optimize the free energy of hydrogen adsorption to the best, promote the HER kinetics under alkaline conditions, and significantly improve the catalytic activity and catalyst life compared to commercial electrodes. However, due to their single active site, ruthenium single-atom catalysts are unlikely to adjust the binding mode of adsorbed intermediates during the reaction and lack synergistic interactions. In certain reactions, such as alkaline hydrogen evolution reactions, the catalytic activity is not as good as that of Ru3 clusters.

[0128] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A Ru3 cluster catalyst with precise atomic number for hydrogen evolution in alkaline water electrolysis, characterized in that: Ru3 clusters are loaded on the carrier oxidized carbon nanotubes, and the loading amount of Ru is 0.8-4.3wt%.

2. The alkaline water electrolysis hydrogen evolution supported type atomic number accurate Ru3 cluster catalyst according to claim 1, characterized in that: The Ru3 cluster has an average particle size of 0.3 nm and is composed of three atoms.

3. A method for preparing a Ru3 cluster catalyst with a precise atomic number for hydrogen evolution in alkaline water electrolysis as claimed in claim 1 or 2, characterized in that: The following steps are involved: Adding carbon nanotubes to the mixed acid and ultrasonically shaking, the carbon nanotubes are evenly dispersed and then placed in an oil bath for magnetic stirring, and then cooled to room temperature, washed with deionized water until neutral, dried, and ground to obtain oxidized carbon nanotubes; The Ru source precursor is ultrasonically dissolved in a solvent to obtain a Ru source precursor solution, which is dropwise added into the solvent in which the oxidized carbon nanotubes are uniformly dispersed, stirred at room temperature, centrifuged to obtain a black product, and dried; The dried black product is placed on a carbon cloth for calcination to obtain a Ru3 cluster catalyst with a precise number of atoms supported on the oxidized carbon nanotubes.

4. The method for preparing the Ru3 cluster catalyst with accurate atomic number for hydrogen evolution in alkaline water electrolysis according to claim 3, characterized in that: The mixed acid is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3; The temperature of the oil bath was 75° C., and the stirring time in the oil bath was 3 h.

5. The method for preparing the Ru3 cluster catalyst with accurate atomic number for hydrogen evolution in alkaline water electrolysis according to claim 3, characterized in that: The Ru source precursor is Ru3(CO) 12 ; The solvent used to prepare the Ru source precursor solution is dichloromethane or tetrahydrofuran, and the concentration of the obtained Ru source precursor solution is 0.2-1 mg / mL; The oxidized carbon nanotubes are uniformly dispersed in dichloromethane, and the concentration of the obtained oxidized carbon nanotube solution is 1 mg / mL; The stirring time at room temperature is 10-12h.

6. The method for preparing the Ru3 cluster catalyst with accurate atomic number for hydrogen evolution in alkaline water electrolysis according to claim 3, characterized in that: The calcination treatment refers to calcination at 350-450° C. for 100-150 seconds in a nitrogen atmosphere.

7. Use of the alkaline water electrolysis hydrogen evolution supported type Ru3 cluster catalyst with precise atomic number as claimed in claim 1 or 2 in hydrogen evolution reaction under alkaline conditions.

8. A method for hydrogen evolution by electrolysis of water, characterized in that: The alkaline water electrolysis hydrogen evolution supported type Ru3 cluster catalyst with precise atomic number as claimed in claim 1 or 2 is used as a catalyst.

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