A composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles and a preparation method and application thereof

Abstract

The present invention belongs to the technical field of green hydrogen production by electrolysis of water, and discloses a composite electrocatalyst of molybdenum disulfide loaded with platinum nanoparticles, its preparation method and application. In the present invention, ammonium molybdate, thiourea and polyvinyl pyrrolidone are dissolved in deionized water, and MoS2 is obtained by heat treatment; an aqueous solution of Na2[PtCl6]·6H2O is added to the dispersion of MoS2, and a composite electrocatalyst of molybdenum disulfide loaded with Pt particles is obtained by annealing. Among them, the molybdenum disulfide nanosheets have a vertically arranged structure and are rich in edge sulfur sites. These highly active edge sulfur sites synergistically act with Pt particles to effectively reduce the reaction barrier for the dissociation of water molecules. At the same time, the active sulfur sites increase the rate of hydrogen generation. The material has a high conductivity at 10 mA cm ‑2 At a current density of 1.5 Å, the overpotential is only 35 mV, and at 20 mA cm ‑2 The present invention promotes the dissociation of water molecules and the generation of hydrogen by combining metal active sites with highly active non-metal sites, significantly improving the performance of the hydrogen evolution reaction in alkaline media.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrolytic water green hydrogen production, and in particular to a preparation method of a composite electrocatalyst. BACKGROUND

[0002] With the continuous development of human society, the demand for energy is increasing, and the use of traditional fossil energy will emit a large amount of carbon dioxide and other pollutants, causing serious pollution to the environment. Hydrogen has the advantages of no pollution and high energy density, and is one of the most effective energy carriers to replace traditional fossil fuels, and has been widely used in hydrogen fuel cell vehicles, deuteron accelerators, production and processing of non-ferrous metals, petroleum refining and other aspects.

[0003] Using solar energy, wind energy and the like to generate electric energy, and producing green hydrogen by electrolyzing water can produce high-purity hydrogen (>95%), and the process does not emit any carbon dioxide, and is a hydrogen production technology with great development potential. Among many water electrolysis hydrogen production technologies, the anion exchange membrane electrolyzer has the advantages of high efficiency, economy and reliability, is conducive to large-scale hydrogen production, and has great development value. However, in the process of hydrogen production by the anion exchange membrane electrolyzer, the hydrogen evolution reaction produces a water dissociation, hydrogen desorption and hydrogen generation process under alkaline conditions, involves multiple reaction steps and proton migration processes, resulting in low hydrogen evolution reaction efficiency of the electrolyzer under low potential conditions and high overpotential. At the same time, under an ampere-level current density, the stability of the catalyst is poor, and cannot meet the actual needs of industrial hydrogen production.

[0004] The existing hydrogen evolution reaction (HER) catalyst design adopts a multi-metal active site strategy to significantly improve the HER activity in alkaline medium through the synergistic effect of multi-site metal active sites. For example, by modifying ruthenium (Ru) on the surface of platinum (Pt), the water dissociation ability can be enhanced, thereby reducing the reaction energy and improving the HER efficiency. In addition, non-noble metals such as nickel (Ni), molybdenum (Mo), cobalt (Co), etc. can also be used to construct multi-site active sites to promote water dissociation and hydrogen generation. For example, Ni-Pt active sites are formed by amorphous Ni(OH)2-coated platinum nanoparticles, showing good HER activity; Mo-Co active sites are formed by single molybdenum atom-doped CoOx; Ni-Mo active sites are constructed by NixMoy alloy / hydroxide interface; and Ni-Cr-Cu active sites are formed by Ni and CrOx co-modified Cu foam. These active sites effectively promote water dissociation through the synergistic effect between metal and non-metal. However, due to the strong adsorption between metal atoms and hydrogen groups, the H-H coupling process after water dissociation is hindered, resulting in the inability to form H2 or the inability of H2 to desorb from the catalyst surface, thereby further leading to low hydrogen evolution reaction efficiency. In addition, in order to improve the activity of the catalyst for hydrogen evolution reaction and reduce the overpotential, researchers have also conducted research, for example, the patent with publication number CN117822023A discloses a preparation method of a composite electrocatalyst of molybdenum disulfide supported platinum nanoclusters for alkaline electrolytic water hydrogen production. By constructing a larger specific surface area of MoS2, more Pt atomic clusters are loaded to improve the catalytic activity of electrolytic water. However, this strategy still has some problems, the electrocatalytic activity does not meet the expected value, and it depends on the control of the size of platinum and reasonable preparation conditions, which increases the difficulty coefficient of preparing samples. Therefore, how to use less Pt, use a more simple experimental procedure and further improve the activity of the electrocatalyst in the hydrogen evolution reaction has become an important problem. SUMMARY

[0005] In view of the above technical problems, the present application provides a composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles and a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] A preparation method of a composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles, the steps are as follows:

[0008] (1) Dissolve ammonium molybdate ((NH4)6Mo7O 24 ), thiourea (NH2CSNH2) and polyvinylpyrrolidone (PVP) in deionized water to obtain a mixed solution I;

[0009] (2) The mixed solution I obtained in step (1) is subjected to heat treatment, centrifugation, washing and drying to obtain black solid MoS2;

[0010] (3) The black solid MoS2 prepared in step (2) is dispersed in a mixed solvent of water and ethanol to obtain mixed solution II; an aqueous solution of Na2[PtCl6]·6H2O is slowly injected into the mixed solution II, and the Pt atoms are completely deposited on the surface of MoS2 by high-temperature treatment, and the product is obtained by cooling, filtering and drying;

[0011] (4) The product prepared in step (3) is subjected to annealing treatment to obtain a composite electrocatalyst of MoS2 loaded with platinum nanoparticles (Pt / E-MoS2).

[0012] In the above step (1), the mass ratio of ammonium molybdate, thiourea and polyvinylpyrrolidone is (60-65):(50-55):(28-32); and the concentration of ammonium molybdate in the mixed solution I is 30-44 g / L.

[0013] In the above step (2), the temperature of heat treatment is 180-260℃, and the time is 15-20h.

[0014] Further, in the above step (2), the temperature of drying is 30-70℃, and the time is 10-15h.

[0015] In the above step (3), the volume ratio of water to ethanol in the mixed solvent is (7-13):1; and the concentration of MoS2 in the mixed solution II is 0.8-1.2 g / L.

[0016] In the above step (3), the concentration of the aqueous solution of Na2[PtCl6]·6H2O is 0.7-1.4 mmol / L; the rate of slowly injecting the aqueous solution of Na2[PtCl6]·6H2O is 10-40 min / mL; and the volume ratio of the aqueous solution of Na2[PtCl6]·6H2O to the mixed solution II is 1:(10-23).

[0017] Further, in the above step (3), the temperature of high-temperature treatment is 90-130℃, and the time is 5-10h; and the drying is performed under vacuum conditions, the temperature of drying is 30-70℃, and the time is 10-15h.

[0018] In the above step (4), the temperature of annealing treatment is 260-350℃, and the time is 1-5h.

[0019] The composite electrocatalyst of molybdenum disulfide-loaded platinum nanoparticles prepared using the above-mentioned preparation method, wherein the molybdenum disulfide has a vertically arranged structure and rich edge sulfur sites. This vertically arranged structure not only ensures the availability of edge sites, improving the overall catalytic activity, but also reduces the exposure of the overall surface area, avoiding the waste of active sites and the occurrence of unnecessary side reactions. On the one hand, a large number of edge sulfur atoms can synergize with Pt nanoparticles to effectively reduce the reaction energy barrier of water dissociation; on the other hand, the moderate interaction between sulfur atoms and hydrogen intermediates can ensure the timely release of hydrogen, promote the HH coupling process, and increase the reaction rate of the alkaline hydrogen evolution reaction (HER).

[0020] Application of the above-mentioned molybdenum disulfide-loaded platinum nanoparticle composite electrocatalyst in hydrogen evolution reaction under alkaline conditions.

[0021] Furthermore, in the above hydrogen evolution reaction, the composite electrocatalyst of molybdenum disulfide loaded with platinum nanoparticles was -2 At a current density of 20 mA cm, the overpotential is 35 mV; and at 20 mA cm -2 The device can run stably for more than 110 hours at a current density of 1.

[0022] The beneficial effects produced by the present invention are:

[0023] (1) Enhanced water dissociation ability: The present invention proposes a composite electrocatalyst for the production of green hydrogen (HER) under alkaline conditions, specifically a molybdenum disulfide (MoS2) nanostructure rich in sulfur (S) edge sites modified by platinum (Pt) nanoparticles. Molybdenum disulfide has a vertically arranged structure and a nanosphere structure with rich edge features. This is because the spatial confinement of the S atoms at the edge of MoS2 causes Pt atoms to preferentially deposit at the edge of MoS2. The large number of edge sulfur atoms contained in the nanospheres synergistically act with the Pt nanoparticles to effectively reduce the reaction energy barrier for water dissociation.

[0024] (2) Promote HH coupling: At the same time, the interaction force between sulfur atoms and hydrogen intermediates is moderate, which can ensure the timely release of hydrogen, promote the HH coupling process, and reduce the overpotential. -2 The overpotential is only 35 mV, which improves the reaction rate of alkaline HER.

[0025] (3) Excellent stability: Pt / E-MoS2 prepared by the present invention is stable at 20mA cm -2 It can operate stably for more than 110 hours at a current density of 100 nm, and its performance is better than that of commercial Pt / C.

[0026] (4) The cost is low: the composite electrocatalyst prepared by the application only uses a small amount of Pt, for example, in the performance test, the atomic content of platinum is determined by inductively coupled plasma (ICP), and the mass fraction of Pt is only 0.57% in the prepared sample, which shows that a small amount of Pt is used to achieve good catalytic effect, saves production cost, is conducive to industrialized production in the later period and meets the actual demand of industrial hydrogen production. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 It is a spherical aberration corrected scanning transmission electron microscope image of low-magnification Pt / E-MoS2.

[0029] Figure 2 It is a spherical aberration corrected scanning transmission electron microscope image of high-magnification Pt / E-MoS2.

[0030] Figure 3 It is an X-ray diffraction spectrum of Pt / E-MoS2.

[0031] Figure 4 It is an X-ray photoelectron spectrum of Pt / E-MoS2.

[0032] Figure 5 It is a high-resolution X-ray photoelectron spectrum of Pt 4f in Pt / E-MoS2.

[0033] Figure 6 It is a linear sweep voltammetry curve diagram using Pt / E-MoS2 as a catalyst.

[0034] Figure 7 It is a hydrogen production cycle stability test diagram using Pt / E-MoS2 as a catalyst. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described clearly and completely below by combining the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] A preparation method of a composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles, the steps are as follows:

[0037] (1) Ammonium molybdate ((NH4)6Mo7O 24 ), thiourea (NH2CSNH2) and polyvinylpyrrolidone (PVP) are dissolved in deionized water to obtain a mixed solution I;

[0038] (2) The mixed solution I obtained in step (1) is subjected to heat treatment, centrifugation, washing and drying to obtain black solid MoS2;

[0039] (3) The black solid MoS2 prepared in step (2) is dispersed in a mixed solvent of water and ethanol to obtain a mixed solution II; an aqueous solution of Na2[PtCl6]·6H2O is slowly injected into the mixed solution II, and the Pt atoms are completely deposited on the surface of MoS2 through high-temperature treatment, and then the product is obtained after cooling, filtration and drying;

[0040] (4) The product prepared in step (3) is subjected to annealing treatment to obtain a composite electrocatalyst of MoS2 loaded with platinum nanoparticles (Pt / E-MoS2).

[0041] In the above step (1), the mass ratio of ammonium molybdate, thiourea and polyvinylpyrrolidone is (60-65):(50-55):(28-32); and the concentration of ammonium molybdate in the mixed solution I is 30-44 g / L.

[0042] In the above step (2), the temperature of heat treatment is 180-260℃, and the time is 15-20h.

[0043] Further, the temperature of drying is 30-70℃, and the time is 10-15h.

[0044] In the above step (3), the volume ratio of water and ethanol in the mixed solvent is (7-13):1; and the concentration of MoS2 in the mixed solution II is 0.8-1.2 g / L.

[0045] In the above step (3), the concentration of the aqueous solution of Na2[PtCl6]·6H2O is 0.7-1.4 mmol / L; the rate of slowly injecting the aqueous solution of Na2[PtCl6]·6H2O is 10-40 min / mL; and the volume ratio of the aqueous solution of Na2[PtCl6]·6H2O to the mixed solution II is 1:(10-23).

[0046] Further, in the above step (3), the temperature of high-temperature treatment is 90-130℃, and the time is 5-10h; and the drying is performed under vacuum conditions, the temperature of drying is 30-70℃, and the time is 10-15h.

[0047] In the above step (4), the temperature of annealing treatment is 260-350℃, and the time is 1-5h.

[0048] Example 1

[0049] The preparation method of the composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles in this example is as follows:

[0050] (1) 625 mg of ammonium molybdate ((NH4)6Mo7O 24 ), 525 mg of thiourea (NH2CSNH2) and 300 mg of surfactant PVP were dissolved in 17 mL of deionized water to obtain a uniform mixed solution under stirring.

[0051] (2) The mixed solution prepared in step (1) was heated in a reaction kettle at 220°C for 17 h.

[0052] (3) The precipitate produced in step (2) was centrifuged, washed, and dried at 50°C for 13 h to obtain a black solid (MoS2).

[0053] (4) 140 mg of the black solid obtained in step (3) was dispersed in 115 mL of a mixed solvent of water-ethanol (volume ratio of water to ethanol was 10:1).

[0054] (5) 10 mL of Na2[PtCl6]·6H2O with a concentration of 1.0 mmol / L was injected into the mixed solution obtained in step (4) at a rate of 25 min / mL, and was allowed to stand at 90°C for 5 h to allow Pt atoms to be completely deposited on the surface of MoS2, and was filtered and dried at 50°C under vacuum for 13 h.

[0055] (6) The product obtained in (5) was annealed at 300°C for 3 h to finally obtain the composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles (Pt / E-MoS2).

[0056] The low-magnification spherical aberration-corrected scanning transmission electron microscope image ( Figure 1 ) and the high-magnification spherical aberration-corrected scanning transmission electron microscope image ( Figure 2 ) of the composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles prepared in this example show that the Pt nanoparticles with a lattice spacing of 0.19 nm are located at the edge of the multilayer MoS2.

[0057] The X-ray diffraction pattern of the composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles prepared in this example is shown in Figure 3 , and the characteristic diffraction peaks of the sample are located at 2θ of 14.4°, 33.5°, 39.5° and 58.3°, respectively, which are directed to the (002), (101), (103) and (110) crystal planes of MoS2.

[0058] The X-ray photoelectron spectrogram of the composite electrocatalyst of molybdenum disulfide supported platinum nanoparticles prepared in this example is shown in Figure 4It can be seen that the composite material contains molybdenum, sulfur, carbon, platinum and oxygen elements.

[0059] The high-resolution X-ray photoelectron spectroscopy of the prepared composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles in this example is shown in Figure 2. Figure 5 As can be seen from the figure, platinum exists in the form of metal in the sample. In addition, the atomic content of platinum is determined by inductively coupled plasma (ICP), and the mass fraction of Pt is only 0.57%.

[0060] Example 2

[0061] The preparation method of the composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles in this example is as follows:

[0062] (1) Dissolve 600 mg of ammonium molybdate ((NH4)6Mo7O 24 ), 500 mg of thiourea (NH2CSNH2) and 280 mg of surfactant PVP in 15 mL of deionized water to obtain a uniform mixed solution under stirring.

[0063] (2) The mixed solution prepared in step (1) is heated in a reaction kettle at 180°C for 15 h.

[0064] (3) The precipitate produced in step (2) is centrifuged, washed, and dried at 30°C for 10 h to obtain a black solid (MoS2).

[0065] (4) Disperse 160 mg of the black solid obtained in step (3) in 130 mL of a mixed solvent of water-ethanol (the volume ratio of water to ethanol is 7:1).

[0066] (5) Inject 13 mL of Na2[PtCl6]·6H2O with a concentration of 0.7 mmol / L into the mixed solution obtained in step (4) at a rate of 10 min / mL, and wait for 10 h at 130°C to allow the Pt atoms to be completely deposited on the surface of MoS2, cool, filter, and dry at 30°C under vacuum for 10 h.

[0067] (6) Anneal the product obtained in (5) at 260°C for 1 h to finally obtain a composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles (Pt / E-MoS2).

[0068] Example 3

[0069] The preparation method of the composite electrocatalyst of molybdenum disulfide loaded platinum nanoparticles in this example is as follows:

[0070] (1) Dissolve 650 mg of ammonium molybdate ((NH4)6Mo7O 24), 550 mg thiourea (NH2CSNH2) and 320 mg surfactant PVP were dissolved in 20 mL of deionized water to obtain a homogeneous mixed solution under stirring.

[0071] (2) The mixed solution prepared in step (1) was heated in a reaction kettle at 260°C for 20 h.

[0072] (3) The precipitate produced in step (2) was centrifuged, washed, and dried at 70°C for 15 h to obtain black solid (MoS2).

[0073] (4) 180 mg of the black solid obtained in step (3) was dispersed in 150 mL of a mixed solvent of water-ethanol (volume ratio of water to ethanol was 13:1).

[0074] (5) 13 mL of Na2[PtCl6]·6H2O with a concentration of 0.7 mmol / L was injected into the mixed solution obtained in step (4) at a rate of 10 min / mL, and was allowed to stand at 100°C for 7 h to allow Pt atoms to be completely deposited on the surface of MoS2, and was cooled, filtered, and dried at 70°C under vacuum for 15 h.

[0075] (6) The product obtained in (5) was annealed at 350°C for 5 h to finally obtain a composite electrocatalyst of MoS2 supported platinum nanoparticles (Pt / E-MoS2).

[0076] Example 4

[0077] The preparation method of the composite electrocatalyst of MoS2 supported platinum nanoparticles of the present example is as follows:

[0078] (1) 600 mg of ammonium molybdate ((NH4)6Mo7O 24 ), 500 mg of thiourea (NH2CSNH2) and 280 mg of surfactant PVP were dissolved in 15 mL of deionized water to obtain a homogeneous mixed solution under stirring.

[0079] (2) The mixed solution prepared in step (1) was heated in a reaction kettle at 180°C for 20 h.

[0080] (3) The precipitate produced in step (2) was centrifuged, washed, and dried at 30°C for 15 h to obtain black solid (MoS2).

[0081] (4) 180 mg of the black solid obtained in step (3) was dispersed in 225 mL of a mixed solvent of water-ethanol (volume ratio of water to ethanol was 13:1).

[0082] (5) 13 mL of Na2[PtCl6] · 6H2O with a concentration of 1.4 mmol / L was injected into the mixed solution obtained in step (4) at a rate of 40 min / mL, and was allowed to stand at 110°C for 8 h to make Pt atoms completely deposit on the surface of MoS2, and was cooled, filtered, and dried at 30°C under vacuum for 15 h.

[0083] (6) The product obtained in (5) was annealed at 260°C for 5 h to finally obtain a composite electrocatalyst of MoS2 supported platinum nanoparticles (Pt / E-MoS2).

[0084] Example 5

[0085] The preparation method of the composite electrocatalyst of MoS2 supported platinum nanoparticles of the present example includes the following steps:

[0086] (1) 650 mg of ammonium molybdate ((NH4)6Mo7O 24 ), 550 mg of thiourea (NH2CSNH2), and 300 mg of a surfactant PVP were dissolved in 15 mL of deionized water to obtain a uniform mixed solution under stirring.

[0087] (2) The mixed solution prepared in step (1) was heated in a reaction kettle at 220°C for 17 h.

[0088] (3) The precipitate produced in step (2) was centrifuged, washed, and dried at 50°C for 13 h to obtain a black solid (MoS2).

[0089] (4) 160 mg of the black solid obtained in step (3) was dispersed in 160 mL of a mixed solvent of water-ethanol (the volume ratio of water to ethanol was 10:1).

[0090] (5) 7 mL of Na2[PtCl6] · 6H2O with a concentration of 1.0 mmol / L was injected into the mixed solution obtained in step (4) at a rate of 25 min / mL, and was allowed to stand at 100°C for 9 h to make Pt atoms completely deposit on the surface of MoS2, and was cooled, filtered, and dried at 70°C under vacuum for 10 h.

[0091] (6) The product obtained in (5) was annealed at 350°C for 3 h to finally obtain a composite electrocatalyst of MoS2 supported platinum nanoparticles (Pt / E-MoS2).

[0092] Comparative Example 1

[0093] The preparation method of MoS2 of the present comparative example is different from that of Example 1 in that the surface is not modified by platinum nanoparticles, and includes the following steps:

[0094] (1) 625 mg of ammonium molybdate ((NH4)6Mo7O24 ), 525 mg thiourea (NH2CSNH2) and 300 mg surfactant PVP were dissolved in 17 mL of deionized water to obtain a uniform mixed solution under stirring.

[0095] (2) The mixed solution prepared in step (1) was heated at 220℃ in a reaction kettle for 17 h. After cooling to room temperature, it was collected.

[0096] (3) The precipitate produced in step (2) was centrifuged, washed thoroughly with water and ethanol, and dried at 50℃ for 13 h to obtain a black solid (E-MoS2).

[0097] Application Example

[0098] The Pt / E-MoS2 obtained in the example and the molybdenum disulfide obtained in Comparative Example 1 as well as a commercially purchased Pt / C catalyst were respectively used for the preparation of green hydrogen by electrocatalysis. In the process of electrocatalytic hydrogen production, the preparation steps of the working electrode were as follows: 5 mg of catalyst and 10 mg of conductive carbon black (EC-300J) were mixed with 500 μL of deionized water, 470 μL of isopropyl alcohol and 30 μL of 117 to form a catalyst ink, which was then ultrasonically treated in cold water for 3 hours. Subsequently, 60 μL of the above catalyst ink was uniformly coated on a carbon cloth (1 cm x 1 cm in size), and the mass loading of the catalyst on the electrode was 0.3 mg cm -2 .

[0099] The above working electrode was used for the hydrogen production performance test of water electrolysis by linear sweep voltammetry (LSV), and the specific test method was as follows:

[0100] In the alkaline electrolyte environment, the hydrogen production performance of the electrode in water electrolysis was studied by linear sweep voltammetry. At a scan rate of 5 mVs -1 , the current-potential curve was obtained within a certain potential range of -0.5 V-0.2 V, and the overpotential of the electrode at different current densities could be obtained from the curve, so that the performance of different catalysts could be compared by the size of the overpotential at a specific current density.

[0101] The linear sweep voltammetry curve of the composite electrocatalyst of the molybdenum disulfide loaded platinum nanoparticles prepared in the example is as Figure 6 shown in the figure. As can be seen from the figure, the overpotential of the sample prepared in Example 1 at a current density of 10 mA cm -2 was 35 mV, the overpotential at a current density of 100 mA cm -2 was 221 mV, and the overpotential of the Pt / C catalyst at a current density of 10 mA cm -2 and 100 mA cm -241 mV and 236 mV, respectively, and the E-MoS2 catalyst at 10 mA cm-2 -2 and 100 mA cm-2 -2 213 mV and 441 mV, respectively, which are significantly higher than the overpotentials of the obtained samples. The test results show that the Pt / E-MoS2 has superior HER catalytic activity. The overpotentials of the catalysts prepared in different examples and comparative examples, and Pt / C are shown in Table 1.

[0102] Table 1. Overpotentials at current densities of 10 mA cm-2 -2 and 100 mA cm-2 -2

[0103]

[0104] As can be seen from Table 1, the overpotential of the Pt / E-MoS2 prepared in Example 1 is significantly lower than that of Comparative Example 1 and the Pt / C catalyst, and has good catalytic performance.

[0105] The above working electrode was used to test the cyclic stability of hydrogen production by electrolysis of water by chronoamperometry, and the specific test method was as follows:

[0106] In an alkaline environment, taking the Pt / E-MoS2 catalyst with a mass fraction of 1.2% as an example, the test was carried out in a 1M KOH solution at an industrial current density of 1 A cm-2 -2 . For the anion exchange membrane water electrolysis cell (AEMWE) assembled based on 1.2% Pt / E-MoS2 and IrO2, the change of voltage with time at 1 A cm-2 -2 was tested, and the test lasted for 1000 hours. The smaller the voltage fluctuation, the better the cyclic stability in an alkaline environment. At the same time, the electrode was also tested by chronoamperometry in a 1M KOH solution at a lower density (such as 20 mA cm-2 -2 ), and the current stability was observed. For example, 1.2% Pt / E-MoS2 could maintain a stable current density for 110 hours, indicating that it had good alkaline cyclic stability. The stability curve of the obtained molybdenum disulfide supported platinum nanoparticle composite electrocatalyst is shown in Figure 7 , and the results prove that Pt / E-MoS2 can be stably operated at a current density of 20 mA cm-2 -2 for 110 hours.

[0107] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A method for preparing a composite electrocatalyst of molybdenum disulfide-supported platinum nanoparticles, characterized in that: Here are the steps: (1) Ammonium molybdate, thiourea and polyvinylpyrrolidone were dissolved in deionized water at a mass ratio of (60-65):(50-55):(28-32) to obtain a mixed solution I with an ammonium molybdate concentration of 30-44 g / L; MoS2 was obtained by heat treatment; (2) The MoS2 prepared in step (1) is dispersed in a mixed solvent with a volume ratio of water and ethanol of (7-13):1 to obtain a mixed solution II with a MoS2 concentration of 0.8-1.2 g / L; a Na2[PtCl6]·6H2O aqueous solution with a concentration of 0.7-1.4 mmol / L is slowly added to the mixed solution II, and the mixture is subjected to a high temperature treatment at 90-130°C for 5-10 h, cooled, filtered, and dried to obtain a product; wherein the rate of slowly adding the Na2[PtCl6]·6H2O aqueous solution is 10-40 min / mL; the volume ratio of the Na2[PtCl6]·6H2O aqueous solution to the mixed solution II is 1:(10-23); (3) The product obtained in step (2) is annealed at 260-350° C. for 1-5 h to obtain a composite electrocatalyst of molybdenum disulfide loaded with platinum nanoparticles.

2. The method for preparing a composite electrocatalyst of molybdenum disulfide-supported platinum nanoparticles according to claim 1, characterized in that: The heat treatment temperature in step (1) is 180-260° C. and the time is 15-20 h.

3. A composite electrocatalyst of molybdenum disulfide-supported platinum nanoparticles prepared by the preparation method according to claim 1 or 2, characterized in that: The molybdenum disulfide has a vertically aligned structure and edge-rich sulfur sites.

4. Use of the composite electrocatalyst of molybdenum disulfide loaded with platinum nanoparticles according to claim 3 in hydrogen evolution reaction under alkaline conditions.

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