Flower-like heteronuclear bimetallic atom catalyst and preparation method and application thereof

Abstract

The invention discloses a preparation method of a flower-like heteronuclear bimetallic atom catalyst, which comprises the following steps: 1) dissolving a metal source precursor in a solvent, mixing with an organic matter, and fully reacting by stirring to prepare a bimetallic precursor wrapped by the organic matter; 2) carrying out annealing treatment on the bimetallic precursor wrapped by the organic matter obtained in the step 1) to obtain a carbonized bimetallic precursor; and 3) carrying out etching treatment on the carbonized bimetallic precursor to obtain the heteronuclear bimetallic atom catalyst. According to the flower-shaped heteronuclear bimetallic atom catalyst provided by the invention, the metal source precursor reacts with the organic matter, then annealing treatment is performed, and finally etching is performed to prepare the flower-shaped heteronuclear bimetallic atom catalyst, and the size of the flower-shaped heteronuclear bimetallic atom catalyst is smaller than 1 [mu] m; the flower-like heteronuclear bimetallic atom catalyst has excellent HER activity and Tafel power, and is suitable for popularization and application in the field of catalysts. And the preparation method is simple, the cost is relatively low, the excellent HER performance is achieved, and the wide application prospect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy materials, and specifically relates to a flower-shaped heteronuclear bimetallic atom catalyst and a preparation method and application thereof. Background Art

[0002] As economic development becomes more and more rapid, the energy crisis it brings is becoming increasingly serious. The research on promoting green energy has long been on the agenda. Hydrogen energy has become a hot topic of research due to its low carbon, clean and efficient characteristics. Among them, the technology of hydrogen evolution by electrolysis of water (HER) using renewable energy is currently the most common method due to its high efficiency and economic advantages. The most common HER catalyst is Pt-based HER catalyst, but its high price limits the development of HER. Ruthenium-based catalysts have similar hydrogen adsorption free energy to Pt and are much cheaper than platinum, so they have the potential to replace platinum-based catalysts. In current research, single-atom catalysts (SACs) show great advantages in reducing metal usage and achieving maximum utilization of precious metals. Although some studies have shown that Ru single-atom catalysts show significant efficiency in alkaline HER reactions, their HER activity and Tafel kinetics need to be further improved.

[0003] By constructing heteronuclear bimetallic atoms, their valence structure can be regulated, which is beneficial to the splitting of H-OH in the previous water dissociation step and improves the HER activity. In addition, the metal carbide scaffold can promote the atomic dispersion of the supported metal through strong electronic interactions, triggering orbital hybridization and charge polarization at the interface, which can also improve the HER activity to a certain extent. In high-pH alkaline electrolytes, in order to improve the performance of Ru-based catalysts for hydrogen evolution in water electrolysis, it is very challenging and practical to develop efficient bimetallic atom catalysts. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main purpose of the present invention is to provide a flower-shaped heteronuclear bimetallic atom catalyst and a preparation method and application thereof, aiming to solve the problem of poor HER activity and Tafel kinetics of existing catalysts.

[0005] The purpose of the present invention is to provide the application of the flower-shaped heteronuclear bimetallic atom catalyst in the field of catalysis.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a flower-shaped heteronuclear bimetallic atom catalyst comprises the following steps:

[0008] 1) dissolving a metal source precursor in a solvent, mixing it with an organic substance, and stirring to fully react to obtain an organic-coated bimetallic precursor;

[0009] 2) annealing the organic-coated bimetallic precursor obtained in step 1) to obtain a carbonized bimetallic precursor;

[0010] 3) Etching the carbonized bimetallic precursor to obtain a heteronuclear bimetallic atomic catalyst.

[0011] In some specific embodiments, the mass ratio of the metal source precursor to the organic matter is (1-5):(1-10).

[0012] In some specific embodiments, the metal source precursor includes a precursor ruthenium source and a precursor molybdenum source in a mass ratio of 1:(100-200), wherein the precursor ruthenium source is one of ruthenium trichloride, ammonium chlororuthenate, and ruthenium acetylacetonate; the precursor molybdenum source is one or more of molybdenum pentachloride, molybdenum chloride, ammonium molybdate, and sodium molybdate.

[0013] In some specific embodiments, the solvent is ethanol, deionized water or a mixture thereof; the organic matter includes one or more of tris(hydroxymethyl)aminomethane, polyoxypropylene polyoxyethylene copolymer solution, and dopamine hydrochloride.

[0014] In some specific embodiments, the stirring condition is: maintaining a rotation speed of 100-500 rpm for 6-8 hours.

[0015] Furthermore, the stirring speed may be one of 100 rpm, 200 rpm, 300 rpm, 400 rpm and 500 rpm.

[0016] In some specific embodiments, the process further includes washing, separating and drying the products obtained in step 1) and step 3).

[0017] In some specific embodiments, the annealing treatment conditions are: in a reducing atmosphere or an inert atmosphere, the temperature is increased to 550-850° C. at a heating rate of 2-10° C. / min and the reaction is maintained for 1-4 hours.

[0018] Furthermore, the annealing treatment temperature can be 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, and is more preferably 700°C; the annealing treatment time is 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, and is more preferably 2h.

[0019] In some specific embodiments, the etching treatment is specifically: using a MOH solution with a molar concentration of 2-5M to stir and etch for 12-36 hours.

[0020] A flower-shaped heteronuclear bimetallic atom catalyst prepared by the above preparation method.

[0021] The application of the aforementioned flower-shaped heteronuclear bimetallic atom catalyst in the field of catalysis.

[0022] Compared with the prior art, the present invention has at least the following advantages:

[0023] 1) The flower-shaped heteronuclear bimetallic atom catalyst provided in the present application is prepared by reacting a metal source precursor with an organic matter, then performing an annealing treatment, and finally etching to obtain a chemically shaped heteronuclear bimetallic atom catalyst, the size of which is less than 1 μm; the flower-shaped heteronuclear bimetallic atom catalyst has excellent HER activity and Tafel power, and is suitable for promotion and application in the catalyst field.

[0024] 2) The preparation method in this application is universal, simple, and relatively low-cost, has excellent HER performance, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below.

[0026] Figure 1 is the XRD pattern of the flower-shaped heteronuclear bimetallic atom catalyst in Example 1 of the present invention;

[0027] Figure 2 This is a SEM image of a single Ru atom in Comparative Example 1 of the present invention;

[0028] Figure 3 The SEM and EDS images of the flower-shaped heteronuclear bimetallic atom catalyst in Example 1 of the present invention;

[0029] Figure 4 This is a scanning linear voltammetry curve of the flower-shaped heteronuclear bimetallic atom catalyst in Example 1 of the present invention;

[0030] Figure 5 is the Tafel slope diagram of the flower-shaped heteronuclear bimetallic atom catalyst in Example 1 of the present invention; DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0032] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0033] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0034] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0035] In the following examples, the polyoxypropylene polyoxyethylene copolymer solution was purchased from Shanghai Titan Technology Co., Ltd., and its technical indicators were average molecular weight 332.48, RG, 98%+;

[0036] In the following examples, the performance of the platinum-based catalyst was tested by scanning the linear voltammetric curve using the CHI760E equipment of Shanghai Chenhua Instrument Co., Ltd.;

[0037] Example 1

[0038] The preparation method of the flower-shaped heteronuclear bimetallic atom catalyst provided in this embodiment comprises the following steps:

[0039] 1) Weigh 0.3 g of dopamine hydrochloride, 0.005 g of ruthenium trichloride, 0.5 g of sodium molybdate, 0.3 g of polyoxypropylene polyoxyethylene copolymer solution and 0.2 g of tris(hydroxymethyl)aminomethane, dissolve in 200 ml of deionized water, stir at 300 rpm for 6 h to completely dissolve, and obtain a front-end product; wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60 ° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0040] 2) placing the organic-coated bimetallic precursor in an alumina ceramic boat and transferring it to a tube furnace, washing it with Ar for 10 min to ensure that oxygen is completely removed, then introducing Ar gas, raising the temperature to 700° C. at a rate of 5° C. / min and maintaining it for 2 h for annealing, and taking it out when the annealing is completed and the temperature drops to room temperature to obtain a carbonized bimetallic precursor;

[0041] 3) The carbonized bimetallic precursor is placed in a beaker, 50 mL of 3 M KOH solution is added, and the mixture is etched with stirring for 24 h. The mixture is washed with deionized water and alcohol, and the filtered product is collected by suction filtration and dried to obtain a flower-shaped heteronuclear bimetallic atomic catalyst for morphological and phase characterization.

[0042] Example 2

[0043] The preparation method of the flower-shaped heteronuclear bimetallic atom catalyst provided in this embodiment comprises the following steps:

[0044] 1) Weigh 0.3 g of dopamine hydrochloride, 0.005 g of ruthenium trichloride, 0.5 g of sodium molybdate, 0.3 g of polyoxypropylene polyoxyethylene copolymer solution and 0.2 g of tris(hydroxymethyl)aminomethane, dissolve in 200 ml of deionized water, stir at 300 rpm for 6 h to completely dissolve, and obtain a front-end product; wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60 ° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0045] 2) placing the organic-coated bimetallic precursor in an alumina ceramic boat and transferring it to a tube furnace, washing it with Ar for 10 min to ensure that oxygen is completely removed, then introducing Ar gas, raising the temperature to 750° C. at a rate of 5° C. / min and maintaining it for 2 h for annealing, and taking it out when the annealing is completed and the temperature drops to room temperature to obtain a carbonized bimetallic precursor;

[0046] 3) The carbonized bimetallic precursor is placed in a beaker, 50 mL of 3 M KOH solution is added, and the mixture is etched with stirring for 24 h. The mixture is washed with deionized water and alcohol, and the filtered product is collected by suction filtration and dried to obtain a flower-shaped heteronuclear bimetallic atomic catalyst for morphological and phase characterization.

[0047] Example 3

[0048] The preparation method of the flower-shaped heteronuclear bimetallic atom catalyst provided in this embodiment comprises the following steps:

[0049] 1) Weigh 0.3 g of dopamine hydrochloride, 0.005 g of ruthenium trichloride, 0.5 g of sodium molybdate, 0.3 g of polyoxypropylene polyoxyethylene copolymer solution and 0.2 g of tris(hydroxymethyl)aminomethane, dissolve in 200 ml of deionized water, stir at 300 rpm for 6 h to completely dissolve, and obtain a front-end product; wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60 ° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0050] 2) The organic-coated bimetallic precursor was placed in an alumina ceramic boat and transferred to a tube furnace. It was purged with Ar for 10 min to ensure that oxygen was completely removed. Then Ar and H were introduced. 2The mixed gas with a mixing ratio of 200 sccm: 20 sccm (10:1) was heated to 700°C at a rate of 5°C / min and maintained for 2 hours for annealing. When the annealing was completed and the temperature dropped to room temperature, the carbonized bimetallic precursor was taken out.

[0051] 3) The carbonized bimetallic precursor is placed in a beaker, 50 mL of 2M KOH solution is added, and the mixture is etched with stirring for 24 h. The mixture is washed with deionized water and alcohol, and the filtered product is collected by suction filtration and dried to obtain a flower-shaped heteronuclear bimetallic atomic catalyst for morphological and phase characterization.

[0052] Example 4

[0053] The preparation method of the flower-shaped heteronuclear bimetallic atom catalyst provided in this embodiment comprises the following steps:

[0054] 1) Weigh 0.3 g of dopamine hydrochloride, 0.003 g of ruthenium trichloride, 0.5 g of sodium molybdate, 0.3 g of polyoxypropylene polyoxyethylene copolymer solution and 0.2 g of tris(hydroxymethyl)aminomethane, dissolve in 200 ml of deionized water, and stir at 300 rpm for 6 h to completely dissolve to obtain a front-end product; wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0055] 2) The organic-coated bimetallic precursor was placed in an alumina ceramic boat and transferred to a tube furnace. It was purged with Ar for 10 min to ensure that oxygen was completely removed. Then Ar and H were introduced. 2 The mixed gas with a mixing ratio of 200 sccm: 20 sccm (10:1) was raised to 750°C at a rate of 5°C / min and maintained for 2 hours for annealing. When the annealing was completed and the temperature dropped to room temperature, the carbonized bimetallic precursor was taken out to obtain;

[0056] 3) The carbonized bimetallic precursor is placed in a beaker, 50 mL of 3 M KOH solution is added, and the mixture is etched with stirring for 24 h. The mixture is washed with deionized water and alcohol, and the filtered product is collected by suction filtration and dried to obtain a flower-shaped heteronuclear bimetallic atomic catalyst for morphological and phase characterization.

[0057] Example 5

[0058] The preparation method of the flower-shaped heteronuclear bimetallic atom catalyst provided in this embodiment comprises the following steps:

[0059] 1) Weigh 0.4 g dopamine hydrochloride, 0.005 g ruthenium trichloride, 0.5 g sodium molybdate, 0.4 g polyoxypropylene polyoxyethylene copolymer solution, and 0.3 g tris(hydroxymethyl)aminomethane in 200 ml deionized water, stir at 300 rpm for 6 h to completely dissolve, obtain a mixture, wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60 ° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0060] 2) The organic-coated bimetallic precursor was placed in an alumina ceramic boat and transferred to a tube furnace. It was purged with Ar for 10 min to ensure that oxygen was completely removed. Then Ar and H were introduced. 2 The mixed gas with a mixing ratio of 200 sccm: 20 sccm (10:1) was heated to 700°C at a rate of 5°C / min and maintained for 2 hours for annealing. When the annealing was completed and the temperature dropped to room temperature, the carbonized bimetallic precursor was taken out.

[0061] 3) The carbonized bimetallic precursor is placed in a beaker, 50 mL of 3 M KOH solution is added, and the mixture is etched with stirring for 24 h. The mixture is washed with deionized water and alcohol, and the filtered product is collected by suction filtration and dried to obtain a flower-shaped heteronuclear bimetallic atomic catalyst for morphological and phase characterization.

[0062] Example 6

[0063] 1) Weigh 0.4 g dopamine hydrochloride, 0.005 g ruthenium trichloride, 0.5 g sodium molybdate, 0.4 g polyoxypropylene polyoxyethylene copolymer solution and 0.3 g tris(hydroxymethyl)aminomethane, dissolve in 200 ml deionized water, stir at 300 rpm for 6 h to completely dissolve, and obtain a front-end product; wash with deionized water and alcohol, collect the filtered product by suction filtration, and place it in a vacuum oven at 60 ° C. and dry overnight to obtain an organic-encapsulated bimetallic precursor;

[0064] 2) The organic-coated bimetallic precursor was placed in an alumina ceramic boat and transferred to a tube furnace. It was purged with Ar for 10 min to ensure that oxygen was completely removed. Then Ar and H were introduced. 2 The mixed gas with a mixing ratio of 200 sccm: 20 sccm (10:1) was raised to 750°C at a rate of 5°C / min and maintained for 3 hours for annealing. When the annealing was completed and the temperature dropped to room temperature, the carbonized bimetallic precursor was taken out to obtain;

[0065] 3) The carbonized bimetallic precursor was placed in a beaker, 50 mL of 3 M KOH solution was added, and the mixture was etched with stirring for 24 h. The mixture was washed with deionized water and alcohol, and the filtered product was collected by suction filtration. After drying, a flower-shaped heteronuclear bimetallic atomic catalyst was obtained for morphological and phase characterization.

[0066] Comparative Example 1

[0067] This comparative example provides a catalyst, whose components and proportions are basically the same as those of Example 1, except that no molybdenum source is added, and its steps and process parameters are the same as those of Example 1.

[0068] Performance Testing

[0069] This application takes Example 1 and Comparative Example 1 as examples to test the performance of the prepared heteronuclear bimetallic atom catalyst, specifically:

[0070] 1) Tissue morphology test

[0071] Taking Example 1 as an example, the carbonized bimetallic precursor and the prepared heteronuclear bimetallic atomic catalyst in the preparation method of the present application were characterized by using a field emission scanning electron microscope from Zeiss, Germany, and a high-resolution powder X-ray diffractometer from Spectris, UK, to characterize their morphology and phase. The results are as follows: Figure 1-Figure 2 As shown, Figure 1 is the XRD pattern of heteronuclear bimetallic atom catalyst. Figure 1 It can be seen that the physical phase is pure Ru element; Figure 2 This is a SEM image of the Ru single-atom catalyst in Comparative Example 1 of the present invention, which shows that it is in a granular state and has obvious agglomeration phenomenon; Figure 3 The SEM and EDS images of the heteronuclear bimetallic atom catalyst of Example 1 show that the synthesized catalyst is in the shape of a self-assembled flower with a diameter of about 1 μm, and Ru and Mo are evenly dispersed on the "petals" of the self-assembled flower; Figure 4 It is the scanning linear voltammetry curve of the heteronuclear bimetallic atom catalyst; Figure 5 This is the Tafel plot of the heteronuclear bimetallic atom catalyst. The Tafel slope of the bimetallic atom catalyst is 16.2 mV / dec, which is better than 29.7 mV / dec of Ru single atom and 36.1 mV / dec of commercial Pt / C, showing excellent kinetics.

[0072] 2) Electrochemical performance test

[0073] The heteronuclear bimetallic atom catalyst in this application is applied to hydrogen evolution by water electrolysis, and its catalytic performance is specifically as follows:

[0074] The electrochemical tests were all conducted at room temperature using a CHI760E electrochemical workstation. The catalyst preparation method is as follows: 10 mg of sample (the heteronuclear bimetallic atom catalyst prepared in Example 1) was dispersed in a mixed solution of 870 μL of anhydrous ethanol, 100 μL of deionized water, and 30 μL of Nafion. The solution was ultrasonicated in an ultrasonic cleaner to become a uniform ink-like state. Then, 20 μL of the solution was dropped on the surface of a glassy carbon electrode using a pipette and dried. A 1M KOH (pH=14) solution was used as an alkaline electrolyte for testing. A three-electrode system was used in the test, using a carbon rod as the counter electrode and Ag / AgCl as the reference electrode. The sample to be tested was titrated on the surface of a glassy carbon electrode (3 mm in diameter), and a scanning linear voltammetric curve test was performed with a scanning speed of 0.1 mV and a potential range of (-0.8 to -1.8). The measured data was calibrated with a reversible hydrogen electrode (RHE) according to the equation

[0075] E RHE =E Ag / AgCl +1.02V

[0076] Test results such as Figure 4 As shown in the data, it can be concluded that the catalyst only needs an overpotential of 19 mV to generate 10 mA / cm -2 The current density is better than 61mV of Ru single atom and 30mV of commercial Pt / C, with superior performance.

[0077] In summary, the preparation method of the flower-shaped heteronuclear bimetallic atom catalyst proposed by the inventors, by selecting suitable metal source precursors and suitable compounds, annealing under high temperature conditions, carbonizing organic matter at high temperature to form a carrier, and performing alkaline etching, demonstrates an efficient method for synthesizing heteronuclear bimetallic atom catalysts. The catalyst synthesized by this method exhibits better HER performance, which can provide a new idea and method for synthesizing self-assembled flower-shaped electrocatalytic materials with high HER performance.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for preparing a flower-shaped heteronuclear bimetallic atom catalyst, characterized in that: The steps include: 1) dissolving a metal source precursor in a solvent, mixing it with an organic substance, and stirring to fully react to obtain an organic-coated bimetallic precursor; 2) annealing the organic-coated bimetallic precursor obtained in step 1) to obtain a carbonized bimetallic precursor; 3) Etching the carbonized bimetallic precursor to obtain a heteronuclear bimetallic atomic catalyst.

2. According to the method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 1, the mass ratio of the metal source precursor to the organic matter is (1-5):(1-10).

3. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 2, characterized in that: The metal source precursor includes a precursor ruthenium source and a precursor molybdenum source in a mass ratio of 1:(100-200), wherein the precursor ruthenium source is one of ruthenium trichloride, ammonium chlororuthenate, and ruthenium acetylacetonate; the precursor molybdenum source is one or more of molybdenum pentachloride, molybdenum chloride, ammonium molybdate, and sodium molybdate.

4. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 3, characterized in that: The solvent is ethanol, deionized water or a mixture thereof; the organic matter includes one or more of tris(hydroxymethyl)aminomethane, polyoxypropylene polyoxyethylene copolymer solution and dopamine hydrochloride.

5. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 4, characterized in that: The stirring condition is: maintaining a rotation speed of 100-500 rpm for 6-8 hours.

6. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 1, characterized in that: The method also includes washing, separating and drying the products obtained in step 1) and step 3).

7. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 5, characterized in that: The annealing treatment conditions are: in a reducing atmosphere or an inert atmosphere, the temperature is raised to 550-850° C. at a heating rate of 2-10° C. / min and the reaction is maintained for 1-4 hours.

8. The method for preparing the flower-shaped heteronuclear bimetallic atom catalyst according to claim 5, characterized in that: The etching treatment specifically includes: using a KOH solution with a molar concentration of 2-5M and stirring for etching for 12-36 hours.

9. A flower-shaped heteronuclear bimetallic atom catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the flower-shaped heteronuclear bimetallic atom catalyst according to claim 9 in the field of catalysis.

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