Platinum-molybdenum metal bi-component nano-catalyst for hydrogen production through water electrolysis and preparation method of platinum-molybdenum metal bi-component nano-catalyst

Abstract

The invention discloses a platinum-molybdenum metal bi-component nano-catalyst for producing hydrogen by electrolyzing water and a preparation method thereof, and belongs to the technical field of nano-catalysts, the platinum-molybdenum metal bi-component nano-catalyst comprises carbon black and platinum-molybdenum metal bi-component nano-particles loaded on the surface of the carbon black, the mass fraction of platinum is 0.9-20%, the mass fraction of molybdenum is 12-25%, and the mass fraction of molybdenum is 0.5-1%. The preparation method comprises the following steps: dissolving platinum acetylacetonate and molybdenum pentachloride in an organic solvent, adding carbon black, heating to obtain mixed powder, and calcining at 500-600 DEG C for 4-6 hours. Metallic molybdenum with the atomic radius and the crystal structure similar to those of metallic platinum is introduced into metallic platinum, the morphology and the electronic structure of the platinum nano-catalyst are regulated and controlled through the interaction between the metallic molybdenum and the metallic platinum, adsorption and desorption of reactants and intermediates are optimized, the catalytic activity of the nano-catalyst in the water electrolysis hydrogen evolution reaction is remarkably improved, and the catalytic activity of the nano-catalyst in the water electrolysis hydrogen evolution reaction is improved. Meanwhile, the usage amount of metal platinum is greatly reduced, and the cost is remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanocatalysts, and in particular relates to a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water and a preparation method thereof. Background Art

[0002] As an efficient and clean secondary energy source, hydrogen energy has high energy density and its combustion product is only pollution-free water. It is the most likely energy carrier to replace traditional fossil fuels and can achieve long-term sustainable development of the economy and society. Up to now, 90% of hydrogen sources are obtained through the reforming of fossil energy, such as hydrogen production from coal, oil, natural gas, and industrial by-products. The conversion rate is low, which will cause serious environmental pollution problems during the preparation process and produce a large amount of carbon dioxide gas. This will aggravate the global greenhouse effect and is undoubtedly very unfavorable to the goal of achieving "dual carbon" emission reduction.

[0003] The use of renewable energy such as solar energy, wind energy, hydropower and other clean energy to produce "green hydrogen" is a greener and more environmentally friendly way to produce hydrogen. Compared with traditional hydrogen production strategies, electrocatalytic water splitting has the advantages of high catalytic efficiency, high purity of hydrogen production, and no greenhouse gas production. It is considered to be an efficient, environmentally friendly and sustainable hydrogen production strategy. As a half-reaction of water splitting, the hydrogen evolution reaction plays a key role in reducing the cost of hydrogen production and improving the catalytic efficiency of hydrogen production. In the catalytic reaction, the interaction between the catalyst and the reactants cannot be too strong or too weak. If the interaction is too strong, the reactants may irreversibly occupy the active sites and poison them. If it is too weak, the surface may have difficulty activating the reactants.

[0004] The precious metal platinum is the best known catalyst for hydrogen production by water electrolysis because its hydrogen adsorption free energy is close to 0. However, platinum is expensive, which will result in excessively high costs. One of the core issues at present is how to develop efficient hydrogen evolution electrocatalysts to reduce the cost of hydrogen production while improving catalytic efficiency. Therefore, reducing the amount of platinum used is crucial. Summary of the invention

[0005] In view of the high price of existing platinum-based hydrogen evolution electrocatalysts, the present invention provides a platinum-molybdenum metal two-component nanocatalyst for hydrogen production by electrolysis of water and a preparation method thereof, which can significantly reduce the cost of metal platinum while maintaining excellent catalytic activity and is expected to achieve large-scale production.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water, comprising carbon black and platinum-molybdenum bimetallic nanoparticles supported on the surface of the carbon black; wherein, the mass fraction of platinum is 0.9% to 20%, the mass fraction of molybdenum is 12% to 25%, and the size of the platinum-molybdenum bimetallic nanoparticles is 1.1 to 2.2 nm.

[0008] A preparation method of a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water, comprising the following steps:

[0009] Step 1: Weigh platinum acetylacetonate and molybdenum pentachloride, dissolve them in a volatile organic solvent to obtain a mixed solution;

[0010] Step 2: Add carbon black to the mixed solution, mix evenly, and heat until the organic solvent completely volatilizes to obtain a mixed powder;

[0011] Step 3: Place the mixed powder in a mixed atmosphere of Ar and H2, calcine at 500 - 600 °C for 4 - 6 h to obtain a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water.

[0012] Further, in Step 1, the molar ratio of platinum acetylacetonate to molybdenum pentachloride is 1:1 - 30, and the solute concentration in the mixed solution is 0.02 mol / L.

[0013] Further, the organic solvent in Step 1 and Step 2 is acetone.

[0014] Further, in Step 2, the molar ratio of carbon black to platinum acetylacetonate is 1:40 - 600.

[0015] Further, the heating method in Step 2 is water bath heating.

[0016] Further, in Step 2, the temperature of the water bath heating is 55 - 65 °C, and the duration is 0.5 - 1 h.

[0017] Further, in Step 3, the heating rate of the calcination is 4 - 6 °C / min.

[0018] The present invention also provides an application of the platinum-molybdenum bimetallic nanocatalyst described in any one of the above technical solutions or the platinum-molybdenum bimetallic nanocatalyst obtained by the preparation method described in any one of the above technical solutions in electrocatalytic hydrogen production by electrolyzing water.

[0019] An electrocatalytic hydrogen production device by electrolyzing water, using a conductive substrate loaded with a platinum-molybdenum bimetallic nanocatalyst as the working electrode.

[0020] Further, the electrocatalytic hydrogen production device by electrolyzing water is realized based on an H-type electrolytic cell, and the electrolyte used is sulfuric acid.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention provides a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water and a preparation method thereof. Using platinum acetylacetonate and molybdenum pentachloride as metal raw materials, by introducing molybdenum with a similar atomic radius and crystal structure to platinum metal, and utilizing the interaction between the two, the morphology and electronic structure of the platinum nanocatalyst are regulated, the adsorption and desorption of reactants and intermediates are optimized, and the catalytic activity of the nanocatalyst for the hydrogen evolution reaction of electrolyzing water is significantly improved. More importantly, the usage amount of platinum metal is greatly reduced, and a current density of 10 mA / cm² can still be achieved at an overpotential of 20 mV with a platinum usage amount as low as 0.9%. While ensuring excellent catalytic activity, the cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a high-resolution transmission electron microscope photograph of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 1 of the present invention;

[0025] Figure 2 It is a high-resolution transmission electron microscope photograph of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 2 of the present invention;

[0026] Figure 3 It is an elemental distribution image of the high-angle annular dark-field image of the scanning transmission electron microscope of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 2 of the present invention;

[0027] Figure 4 It is a line scan elemental distribution image of the high-angle annular dark-field image of the scanning transmission electron microscope of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 2 of the present invention;

[0028] Figure 5 It is the X-ray photoelectron spectrum of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 2 of the present invention;

[0029] Figure 6 It is a high-resolution transmission electron microscope photograph of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in Example 3 of the present invention;

[0030] Figure 7 The hydrogen evolution current density curve of the platinum-molybdenum bimetallic nanocatalyst obtained in Example 1 of the present invention for hydrogen production by electrolyzing water at different potentials in the hydrogen production reduction reaction by electrolyzing water;

[0031] Figure 8 The hydrogen evolution current density curve of the platinum-molybdenum bimetallic nanocatalyst obtained in Example 2 of the present invention for hydrogen production by electrolyzing water at different potentials in the hydrogen production reduction reaction by electrolyzing water;

[0032] Figure 9 The change curve of overpotential with time at a current density of 10 mA / cm² in the hydrogen production reduction reaction by electrolyzing water of the platinum-molybdenum bimetallic nanocatalyst obtained in Example 2 of the present invention for hydrogen production by electrolyzing water;

[0033] Figure 10 The hydrogen evolution current density curve of the platinum-molybdenum bimetallic nanocatalyst obtained in Example 3 of the present invention for hydrogen production by electrolyzing water at different potentials in the hydrogen production reduction reaction by electrolyzing water;

[0034] Figure 11 The change curve of overpotential with time at a current density of 10 mA / cm² in the hydrogen production reduction reaction by electrolyzing water of the platinum-molybdenum bimetallic nanocatalyst obtained in Example 3 of the present invention for hydrogen production by electrolyzing water. Detailed implementation manners

[0035] To further understand the present invention, the preferred implementation schemes of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0036] For all raw materials of the present invention, there is no particular limitation on their sources, and they can be purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0037] For all raw materials of the present invention, there is no particular limitation on their purity. The present invention preferably adopts analytical purity or the conventional purity requirements in the field of atomic layer deposition.

[0038] For all raw materials and process procedures of the present invention, their grades or abbreviations all belong to the conventional grades or abbreviations in the field, and each grade or abbreviation is clear and definite in the field of its related uses. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the grades, abbreviations and corresponding uses, or implement them using the corresponding equipment.

[0039] The present invention will be further described in detail below in conjunction with examples:

[0040] Example 1

[0041] In this example, a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water was prepared, which specifically included the following steps:

[0042] Step 1: Weigh 13.1 mg of platinum acetylacetonate and 45.5 mg of molybdenum pentachloride, place them in a 50 mL beaker, add 10 mL of acetone solution, and dissolve them by ultrasonic treatment to obtain a mixed solution.

[0043] Step 2: Add 50 mg of carbon black to the mixed solution, ultrasonically treat for 0.5 h until evenly mixed, and heat it in a water bath until the acetone completely evaporates. The temperature of the water bath heating is 60 °C and the duration is 30 min to obtain a mixed powder.

[0044] Step 3: Place the mixed powder in a 5% H2 / Ar atmosphere and calcine it at 600 °C for 6 h to obtain a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water.

[0045] By inductively coupled plasma atomic emission spectrometry, it was determined that the mass fraction of platinum atoms in the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was 5.2%, and the mass fraction of molybdenum atoms was 18.59%.

[0046] The high-resolution transmission electron microscope photograph of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example is as Figure 1 shown, where the black nanoparticles are platinum-molybdenum bimetallic nanoparticles loaded on the surface of carbon black, and the size distribution is in the range of 1.3 - 2.0 nm.

[0047] Using an H-type commercial electrolytic cell, the hydrogen evolution performance of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was tested.

[0048] Specifically, in the H-type commercial electrolytic cell, a glassy carbon electrode loaded with the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was used as the cathode. Specifically, 4 mg of the platinum-molybdenum bimetallic nanocatalyst was dispersed in a mixed solution of 920 μL of absolute ethanol and 80 μL of nafion, ultrasonically treated in an ice bath for 30 min, and then evenly dispersed on a glassy carbon electrode with a surface area of 1.13 cm 2 to obtain the cathode, where the loading amount of the platinum-molybdenum bimetallic nanocatalyst was 0.5 mg / cm 2 ; the anode was a graphite rod, and the reference electrode was a mercury / hydrogen sulfite electrode; a 0.5 mol / L dilute sulfuric acid was used as the electrolyte, and the ion exchange membrane in the middle of the electrolytic cell was a nafion117 membrane.

[0049] Using a Chenhua electrochemical workstation, the polarization curve performance of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was tested, and the test results are as Figure 7As shown, it can be seen that the catalyst achieves a current density of 10 mA / cm² at an overpotential of 18 mV.

[0050] Example 2

[0051] In this example, a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water was prepared. Compared with Example 1, the only difference in the preparation process is that: the weight of platinum acetylacetonate in Step 1 was adjusted to 3.75 mg, and the weight of molybdenum pentachloride was adjusted to 52.04 mg; the remaining steps are exactly the same.

[0052] By inductively coupled plasma atomic emission spectrometry, it was determined that the mass fraction of platinum atoms in the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example is 1.4%, and the mass fraction of molybdenum atoms is 25.32%.

[0053] The high-resolution transmission electron microscope image of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example is as Figure 2 shown, where the black nanoparticles are platinum-molybdenum bimetallic nanoparticles supported on the surface of carbon black, and the size distribution is in the range of 1.1 - 2.0 nm.

[0054] Figure 3 is the elemental distribution image of the scanning transmission electron microscope high-angle annular dark field image of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example. Further, line scanning surface analysis was performed on the Figure 3 scored area, and the line scanning elemental distribution image as shown in Figure 4 was obtained. It can be seen that metallic platinum and metallic molybdenum are evenly distributed in the obtained black nanoparticles, confirming the synthesis of platinum-molybdenum bimetallic nanoparticles.

[0055] Figure 5 is the X-ray photoelectron spectrum of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example. Compared with pure metallic platinum, by introducing metallic molybdenum in this example, the electronic structure of metallic platinum was regulated, making metallic platinum present in an oxidized state.

[0056] Referring to the method of Example 1, using an H-type commercial electrolytic cell, the hydrogen evolution performance of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was tested.

[0057] Using a Chenhua electrochemical workstation, the polarization curve performance of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was tested. The test results are as Figure 8 shown, and it can be seen that the catalyst achieves a current density of 10 mA / cm² at an overpotential of 20 mV.

[0058] The chronopotentiometry performance test of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was further carried out using a Chenhua electrochemical workstation to test the change of potential with time of the platinum-molybdenum bimetallic nanocatalyst at a current density of 10 mA / cm². The test results are as Figure 9 shown. It can be seen that this catalyst can stably electrolyze water to produce hydrogen for more than 70 h at a current density of 10 mA / cm², and the potential decay is less than 20 mV.

[0059] Example 3

[0060] In this example, a platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water was prepared. Compared with Example 1, the difference in the preparation process is only that: the weight of platinum acetylacetonate in Step 1 was adjusted to 2.54 mg, and the weight of molybdenum pentachloride was adjusted to 52.88 mg; the remaining steps are exactly the same.

[0061] By inductively coupled plasma atomic emission spectrometry, it was determined that the mass fraction of platinum atoms in the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example is 0.9%, and the mass fraction of molybdenum atoms is 21.88%.

[0062] The high-resolution transmission electron microscope photograph of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example is as Figure 6 shown, where the black nanoparticles are platinum-molybdenum bimetallic nanoparticles supported on the surface of carbon black, and the size distribution is in the range of 1.4 - 2.2 nm.

[0063] Referring to the method of Example 1, the hydrogen evolution performance of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was tested using an H-type commercial electrolytic cell.

[0064] The polarization curve performance test of the platinum-molybdenum bimetallic nanocatalyst for hydrogen production by electrolyzing water obtained in this example was carried out using a Chenhua electrochemical workstation. The test results are as Figure 10 shown. It can be seen that this catalyst achieves a current density of 10 mA / cm² at an overpotential of 20 mV. Further, the chronopotentiometry performance test of this nanocatalyst was carried out, and the test results are as Figure 11 shown. It can be seen that this catalyst can stably electrolyze water to produce hydrogen for nearly 70 h at a current density of 10 mA / cm², and the potential decay is less than 20 mV.

[0065] The above is a detailed introduction to a platinum-molybdenum metal binary nanocatalyst for hydrogen production by electrolyzing water and its preparation method proposed by the present invention. Specific examples are used in this article to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water, characterized in that: It includes carbon black and platinum-molybdenum metal two-component nanoparticles loaded on the surface of the carbon black; wherein the mass fraction of platinum is 0.9% to 20%, the mass fraction of molybdenum is 12% to 25%, and the size of the platinum-molybdenum metal two-component nanoparticles is 1.1 to 2.2 nm.

2. A method for preparing a platinum-molybdenum metal two-component nanocatalyst for electrolysis of water to produce hydrogen, characterized in that: The following steps are involved: Step 1, weighing platinum acetylacetonate and molybdenum pentachloride, and dissolving them in a volatile organic solvent to obtain a mixed solution; Step 2, adding carbon black to the mixed solution, mixing evenly, and heating until the organic solvent is completely volatilized to obtain a mixed powder; Step 3: placing the mixed powder in a mixed atmosphere of Ar and H2, and calcining at 500-600°C for 4-6 hours to obtain a platinum-molybdenum metal two-component nanocatalyst for hydrogen production by electrolysis of water.

3. The method for preparing a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water according to claim 2, characterized in that: In step 1, the molar ratio of platinum acetylacetonate to molybdenum pentachloride is 1:1-30, and the solute concentration in the mixed solution is 0.02 mol / L.

4. The method for preparing a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water according to claim 2, characterized in that: In step 2, the molar ratio of carbon black to platinum acetylacetonate is 1:40-600.

5. The method for preparing a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water according to claim 2, characterized in that: The heating method in step 2 is water bath heating.

6. The method for preparing a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolysis of water according to claim 5, characterized in that: In step 2, the water bath heating temperature is 55-65° C. and the heating time is 0.5-1 h.

7. An electrocatalytic water electrolysis hydrogen production device, characterized in that: A conductive substrate loaded with a platinum-molybdenum metal two-component nanocatalyst for producing hydrogen by electrolyzing water obtained by the method of any one of claims 2 to 6 is used as a working electrode.

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