MoS.SUB.x.O.SUB.y./carbon nanocomposite material, preparation method therefor and use thereof

Abstract

Provided are a MoS.sub.xO.sub.y/carbon nanocomposite material, a preparation method therefor and a use thereof. In the MoS.sub.xO.sub.y/carbon nanocomposite material, 2.5≤x≤3.1, 0.2≤y≤0.7, and the mass percent of MoS.sub.xO.sub.y is 5%-50% based on the total mass of the nanocomposite material. When the MoS.sub.xO.sub.y/carbon nanocomposite material is used as a catalyst for an electrocatalytic hydrogen evolution reaction, the current density is 150 mA/cm.sup.2 or more at an overpotential of 300 mV. The difference between this performance and the performance of a commercial 20% Pt/C catalyst is relatively small, or even equivalent; and this performance is far better than the catalytic performance of an existing MOS.sub.2 composite material. The MoS.sub.xO.sub.y/carbon nanocomposite material also has a good catalytic stability, and after 8,000 catalytic cycles, the current density thereof is only decreased by 3%, thus exhibiting a very good catalytic performance and cycle stability.

Claims

1. A MoS.sub.xO.sub.y/carbon nanocomposite material, wherein 2.5≤x≤3.1, 0.2≤y≤0.7.

2. The nanocomposite material according to claim 1, wherein the MoS.sub.xO.sub.y accounts for 5-50% in mass, based on the total mass of the nanocomposite material.

3. The nanocomposite material according to claim 2, wherein the MoS.sub.xO.sub.y has an amorphous structure.

4. A cathode electrode, wherein the cathode electrode comprises a base electrode and the MoS.sub.xO.sub.y/carbon nanocomposite material according to claim 1 coated on the surface of the base electrode, wherein the base electrode is an inert electrode.

5. The cathode electrode according to claim 4, wherein the base electrode is selected from the group consisting of a glassy carbon electrode, a graphite electrode, an ITO electrode and an FTO electrode.

6. A device of hydrogen production by water electrolysis, wherein the device comprises the cathode electrode according to claim 4.

7. A hydrogen fuel cell device, wherein the hydrogen fuel cell device comprises a hydrogen fuel cell body and the device of hydrogen production by water electrolysis according to claim 6.

8. An electric equipment comprising the hydrogen fuel cell device according to claim 7.

9. The electric equipment according to claim 8, wherein the electric equipment is an electric vehicle, an electric tricycle or an electric bicycle.

10. A method for preparing the nanocomposite material according to claim 1, comprising: (1) dispersing a carbon source in a solvent to obtain a carbon source dispersion; (2) adding a sulfur source and a molybdenum source to the carbon source dispersion to obtain a mixed solution; and (3) irradiating the mixed solution by a γ-ray or an electron beam; after irradiation, separating and drying to obtain the nanocomposite material.

11. The method for preparing the nanocomposite material according to claim 10, wherein the sulfur source and the molybdenum source come from the same compound, and the compound is present in the mixed solution at a concentration of 1-10 mg/mL, or 1-5 mg/mL; or the sulfur source and the molybdenum source come from the different compounds, wherein the molybdenum source and the sulfur source are present in the mixed solution at a concentration of 2-10 mg/mL; a ratio of the total moles of molybdenum atoms in the molybdenum source to the total moles of sulfur atoms in the sulfur source is 1:2-1:6.

12. The method for preparing the nanocomposite material according to claim 11, wherein the sulfur source and the molybdenum source come from the same compound, and the compound is at least one selected from the group consisting of ammonium tetrathiomolybdate and sodium tetrathiomolybdate; and/or the sulfur source and the molybdenum source come from the different compounds, the sulfur source is at least one selected from the group consisting of thiourea and sodium thiosulfate, and the molybdenum source is at least one selected from the group consisting of ammonium molybdate, molybdenum pentachloride, and sodium molybdate.

13. The method for preparing the nanocomposite material according to claim 10, wherein a ratio of the carbon source to the solvent is 1-10 mg:1 mL.

14. The method for preparing the nanocomposite material according to claim 10, wherein in step (3), an absorbed dose rate during irradiation of the mixed solution is 30-30,000 Gy/min, and an absorbed dose is 20,000-400,000 Gy.

15. The method for preparing the nanocomposite material according to claim 10, wherein the γ-ray is produced by .sup.60Co source; and the electron beam is generated by an electron accelerator having an energy of 0.5-5 MeV.

16. The method for preparing the nanocomposite material according to claim 10, wherein before irradiating the mixed solution in step (3), the method further comprises a step of feeding an inert gas into the mixed solution.

17. The method for preparing the nanocomposite material according to claim 16, wherein the inert gas is nitrogen, argon, or a mixture thereof.

18. The method for preparing the nanocomposite material according to claim 10, wherein after separating in step (3), a solid product separated is successively washed by sonication with a water-miscible alcohol and water.

19. The method for preparing the nanocomposite material according to claim 10, wherein the carbon source is dispersed by sonication for 30-100 minutes; and/or the carbon source is at least one selected from the group consisting of carbon black, carbon nanotube, carbon nanohorn, graphite oxide and sulfonated graphite oxide; and/or the solvent is at least one selected from the group consisting of ethylene glycol, glycerol and water.

20. A method of conducting an electrochemical hydrogen evolution reaction comprising utilizing the MoS.sub.xO.sub.y/carbon nanocomposite material according to claim 1 in conducting the electrochemical hydrogen evolution reaction.

Description

DESCRIPTION OF THE DRAWINGS

(1) In order to illustrate the examples of the present application and the technical solutions of the prior art more clearly, the drawings used in the examples and the prior art will be briefly described. It is apparent that the drawings in the following description are only some examples of the application. Those skilled in the art can obtain other drawings based on these drawings without inventive efforts.

(2) FIG. 1 is a transmission electron microscope (TEM) image of the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Example 1.

(3) FIG. 2 is an X-ray diffraction (XRD) pattern of the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Example 1.

(4) FIG. 3 is a spectrum of X-ray photoelectron spectroscopy (XPS) of the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Example 1; wherein FIG. 3A is an XPS high resolution diagram of Mo; and FIG. 3B is an XPS high resolution diagram of S.

(5) FIG. 4 is a linear sweep voltammetry test (LSV) diagram of the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Example 1 on a glassy carbon electrode at different loading.

(6) FIG. 5 is a linear sweep voltammetry test (LSV) diagram of the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Example 1 after catalytic cycles.

DETAILED DESCRIPTION OF THE INVENTION

(7) The present application firstly provides a MoS.sub.xO.sub.y/carbon nanocomposite material, wherein 2.5≤x≤3.1, 0.2≤y≤0.7, preferably 2.6≤x≤3.1, 0.25≤y≤0.7. In a particular embodiment of the present application, based on the total weight of the nanocomposite material, the weight percent of MoS.sub.xO.sub.y is 5-50%, preferably 15-40%. In a particular embodiment of the present application, the MoS.sub.xO.sub.y has an amorphous structure, which is more likely to expose more catalytic active sites of reaction than the ordered crystal structure.

(8) The present application also provides a method for preparing the nanocomposite material mentioned above, wherein the method comprises:

(9) (1) dispersing a carbon source in a solvent to obtain a carbon source dispersion, preferably dispersing by sonication for 30-100 minutes;

(10) in a particular embodiment of step (1), the ratio of carbon source to solvent is 1-10 mg:1 mL; the carbon source is preferably at least one selected from the group consisting of carbon black, carbon nanotube, carbon nanohorn, graphite oxide, and sulfonated graphite oxide; the solvent is preferably at least one selected from the group consisting of ethylene glycol, glycerol and water, the water is preferably deionized water; and in a particular embodiment, preferably dispersing by sonication is performed for 60-100 minutes; and the power of sonication can be 500-1,200 W.
(2) adding a sulfur source and a molybdenum source to the carbon source dispersion to obtain a mixed solution;
in a particular embodiment of step (2), the sulfur source and the molybdenum source can be the same compound, or different compounds; when the sulfur source and the molybdenum source come from the same compound, the compound contains both sulfur and molybdenum, and the compound includes but not limited to ammonium tetrathiomolybdate or sodium tetrathiomolybdate, or a combination thereof; in a particular embodiment, the compound containing both sulfur and molybdenum is present in the mixed solution at a concentration of 1-10 mg/mL, preferably 1-5 mg/mL; when the sulfur source and the molybdenum source come from the different compounds, the sulfur source includes but not limited to at least one of thiourea and sodium thiosulfate; the molybdenum source includes but not limited to at least one of ammonium molybdate, molybdenum pentachloride and sodium molybdate; the molybdenum source and the sulfur source are present in the mixed solution at a concentration of 2-10 mg/mL, and a ratio of the total moles of molybdenum atoms in the molybdenum source to the total moles of sulfur atoms in the sulfur source is 1:2-1:6;
(3) irradiating the mixed solution by a γ-ray or an electron beam; after completion of irradiation, separating and drying to obtain the nanocomposite material.

(11) In a particular embodiment of step (3), the absorbed dose rate during irradiation of the mixed solution is 30-30,000 Gy/min, preferably 50-30,000 Gy/min, and the absorbed dose may be 20,000-400,000 Gy, preferably 50,000-400,000 Gy. The γ-ray can be produced by .sup.60Co γ-ray source; and the electron beam is generated by an electron accelerator having an energy of 0.5 to 5 MeV. Preferably, before irradiation of the mixed solution, an inert gas may be introduced into the mixed solution for removing dissolved oxygen in the mixed solution. The inert gas may be selected from nitrogen, argon, or a mixed gas thereof; preferably selected from high purity nitrogen or high purity argon. The high purity nitrogen or high purity argon gas refers to nitrogen or argon having a purity of 99.999% or more. The separation may be carried out by conventional filtration, centrifugation or the like; and the drying may be carried out at a temperature of 30-60° C. for 12-24 hours.

(12) Preferably, after separating in step (3), the solid product separated is successively washed by sonication with water-miscible alcohol and water, and then separated. The water-miscible alcohol is preferably ethanol. In a particular embodiment, it may be necessary to repeat the above washing-filtration operation several times to remove the solvent introduced in the step (1). In general, the separated solid product is successively washed by sonication with a water-miscible alcohol and water, preferably deionized water, and then it is subjected to a separation treatment, which can be repeated for 1-3 times.

(13) The present application also provides use of the MoS.sub.xO.sub.y/carbon nanocomposite material mentioned above in the electrochemical hydrogen evolution reaction. Specifically, the MoS.sub.xO.sub.y/carbon nanocomposite material can be used as a catalyst for the electrochemical hydrogen evolution reaction.

(14) The present application also provides a cathode electrode for electrolyzing water to produce hydrogen (which is an electrochemical hydrogen evolution reaction), wherein the cathode electrode comprises a base electrode and the MoS.sub.xO.sub.y/carbon nanocomposite material coated on the surface of the base electrode. The base electrode is an inert electrode. In a particular embodiment, the base electrode can be selected from a gold electrode, a platinum electrode, a glassy carbon electrode, a graphite electrode, an ITO electrode or an FTO electrode and the like.

(15) The cathode electrode can be obtained by the following method: firstly dissolving a MoS.sub.xO.sub.y/carbon nanocomposite material and a film forming agent (for example, a Nafion membrane solution) in a solvent, dispersing uniformly to obtain a catalyst solution; and then coating the catalyst solution on the surface of the inert electrode and drying.

(16) The present application further provides a device of hydrogen production by water electrolysis, wherein the device comprises the cathode electrode provided by the present application. It should be noted that, the device of hydrogen production by water electrolysis provided by the present application employs the cathode electrode provided by the present application. The other components required for the device of hydrogen production by water electrolysis, such as anode electrode, electrolytic cell, and electrolyte solution and the like can be implemented by the related technical solutions in the prior art, which are not defined herein.

(17) The present application also provides a hydrogen fuel cell device, wherein the hydrogen fuel cell device comprises a hydrogen fuel cell body and the device of hydrogen production by water electrolysis provided by the present application. The device of hydrogen production by water electrolysis provided by the present application is used for supplying hydrogen gas to the hydrogen fuel cell body. The structure and preparation process of the hydrogen fuel cell body belong to the prior art. In a particular embodiment, any hydrogen fuel cell in the prior art can be used as the hydrogen fuel cell body in the present application, and the device of hydrogen production by water electrolysis provided by the present application is connected thereto for supplying hydrogen gas. The device of hydrogen production by water electrolysis can be connected to the hydrogen fuel cell body by using the related technical solutions in the prior art, which are not defined herein.

(18) The present application also provides an electric equipment comprising the hydrogen fuel cell device mentioned above. In addition to the hydrogen fuel cell device, the other parts of the electric device can be implemented by the related technical solutions in the prior art, which are not defined herein. In the present application, the electric equipment comprises but not limited to an electric vehicle, an electric tricycle or an electric bicycle.

(19) The technical solutions in the examples of the present application are clearly and completely described in the following with reference to the drawings in the examples of the present application. It is apparent that the described examples are only a part of the examples of the present application, not all of examples. All other examples obtained by the ordinary skilled in the art without creative work based on the examples of the present application are within the scope of the present application.

(20) The experimental methods described in the following examples, unless otherwise specified, are conventional methods. The reagents and materials, unless otherwise specified, are commercially available.

Example 1: Preparation and Application of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(21) Preparation of MoS.sub.xO.sub.y/Carbon Nanocomposite Material

(22) 80 mg acetylene black was dispersed into 20 mL ethylene glycol (4 mg/mL), and ultrasonically dispersed for 60 minutes with an ultrasonic processor (at an ultrasonic power of 650 W) at room temperature to obtain an acetylene black dispersion. 40 mg ammonium tetrathiomolybdate was added to obtain a mixed solution. The mixed solution was transferred to an irradiated tube, high-purity nitrogen was fed for 30 minutes. The irradiated tube was sealed with a rubber stopper, and then was irradiated at room temperature in .sup.60Co γ-ray irradiation apparatus at a dose rate of 50 Gy/min, and an absorbed dose of 50 kGy. After irradiation, the sample was filtered through a polypropylene (PP) membrane having a pore size of 0.45 μm. After filtration, filter cake was rinsed with ethanol, filtered and washed with deionized water, ultrasonically treated for 5 minutes when washing, and then the solution was filtered again after sonication, and repeated for three times to remove residual ethylene glycol. After washing, the product was dried in a vacuum oven at 40° C. for 12 hours to obtain a powdery MoS.sub.xO.sub.y/carbon nanocomposite material.

(23) TEM characterization was performed for the MoS.sub.xO.sub.y/carbon nanocomposite material prepared, the results of which are shown in FIG. 1. It can be seen from FIG. 1 that after radiation reduction, the acetylene black material had a particle size of about 20 nm. In the MoS.sub.xO.sub.y/carbon nanocomposite material, in addition to the partially ordered structure of the acetylene black material, no ordered oxygen-doped molybdenum sulfide structure is formed because the radiation-induced reduction reaction was carried out at room temperature. Under such mild conditions, it is disadvantageous for the atoms to be arranged as an ordered crystal structure. The amorphous structure is more likely to expose more catalytic active sites than the ordered crystal structure.

(24) XRD characterization was performed for the MoS.sub.xO.sub.y/carbon nanocomposite material prepared, which further verified that the formed nanocomposites did not have an ordered oxygen-doped molybdenum sulfide structure, that is, the oxygen-doped molybdenum sulfide was an amorphous structure. The results are shown in FIG. 2. In FIG. 2, the broadening peak with 2θ being about 22° is the (002) diffraction peak of carbon material, the small peak with 2θ being 43° is the (100) diffraction peak of carbon material. There are no characteristic diffraction peaks of oxygen-doped molybdenum sulfide material in the XRD pattern.

(25) XPS characterization was performed for the MoS.sub.xO.sub.y/carbon nanocomposite material prepared. The results are shown in FIG. 3A and FIG. 3B. As can be seen from FIG. 3A, molybdenum in ammonium tetrathiomolybdate was reduced to Mo.sup.4+, and Mo—S bond and Mo—O bond coexisted. It can be seen from FIG. 3B that S.sub.2.sup.2− and S.sup.2− coexisted in the material. The mass percentage of MoS.sub.xO.sub.y in the MoS.sub.xO.sub.y/carbon composite material determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) was 15%, wherein x was 2.89, and in combination with XPS, y was 0.58.

(26) Catalytic Performance Test of MoS.sub.xO.sub.y/Carbon Nanocomposite Material

(27) The electrocatalytic hydrogen evolution reaction performance of the prepared MoS.sub.xO.sub.y/carbon nanocomposite material was tested by a three-electrode system. A saturated calomel electrode (SCE) was used as the reference electrode, and a 1 cm.sup.2 Pt electrode was used as the counter electrode. A glassy carbon electrode coated with MoS.sub.xO.sub.y/carbon nanocomposite material on the surface was used as the working electrode, and 0.5 M H.sub.2SO.sub.4 was used as the electrolyte. The Shanghai Chenhua's CHI 760e electrochemical workstation was used for testing.

(28) The working electrode was prepared by a drop casting method. In particular, 4 mg MoS.sub.xO.sub.y/carbon black nanocomposite material was weighed and dispersed in a 1 mL mixed solvent of ultrapure water/ethanol (V.sub.water:V.sub.ethanol=4:1), then 40 μL 5% Nafion membrane solution was added, and a uniform catalyst solution was obtained after ultrasonic dispersion by an ultrasonic processor for more than 30 minutes at room temperature. 2, 3, 4, 5, 6 and 8 μL of the catalyst solution was respectively drop cast on the surface of an L-type glassy carbon electrode having a diameter of 3 mm, which has been smoothly polished. The working electrode with a catalyst loading of 0.110, 0.165, 0.220, 0.275, 0.330 and 0.440 mg/cm.sup.2 was formed after the surface was completely dried, and was used for linear sweep voltammetry (LSV). The test results are shown in FIG. 4 and FIG. 5.

(29) Testing parameters: the linear sweep voltammetry test (LSV) has a sweep rate of 5 mV/s and a scan range of 0.2 to −0.4 V (relative to the reversible hydrogen electrode (RHE for short)). The cyclic voltammetry test has a sweep rate of 50 mV/s and a scan range of 0 to −0.3 V (relative to RHE).

(30) It can be seen from FIG. 4 that when the loading of the catalyst on the glassy carbon electrode was increased from 0.110 mg/cm.sup.2 to 0.330 mg/cm.sup.2, the current density also increased accordingly, indicating that the catalytic performance can be improved by increasing the catalyst loading within this loading range. However, the increase of current density is not proportional to the catalyst content, indicating that the catalyst utilization rate decreases, and as the catalyst loading continues to increase, the excess catalyst may hinder the mass transfer step between the proton of the hydrogen evolution reaction and the surface of catalyst, resulting in a continued decrease in the utilization of the catalyst and a decrease in the current density.

(31) FIG. 5 is a linear sweep voltammetry (LSV) diagram of the MoS.sub.xO.sub.y/carbon nanocomposite material after catalytic cycles. As can be seen from FIG. 5, the MoS.sub.xO.sub.y/carbon nanocomposite material has very good catalytic stability. The current density only decreased by 3% at an overpotential of 300 mV after 8,000 catalytic cycles. There is a slight increase in the catalytic initial voltage of the composite material for the HER reaction due to the partial inactivation of some active sites during the catalysis.

Example 2: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(32) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that acetylene black in Example 1 was replaced by carbon nanotube. The mass percentage of MoS.sub.xO.sub.y in the composite material was 17%, wherein x was 2.91 and y was 0.58.

Example 3: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(33) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that acetylene black in Example 1 was replaced by graphite oxide. The mass percentage of MoS.sub.xO.sub.y in the composite material was 21%, wherein x was 2.81 and y was 0.69.

Example 4: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(34) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that acetylene black in Example 1 was replaced by carbon nanohorn. The mass percentage of MoS.sub.xO.sub.y in the composite material was 19%, wherein x was 2.85 and y was 0.51.

Example 5: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(35) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that acetylene black in Example 1 was replaced by sulfonated graphite oxide. The mass percentage of MoS.sub.xO.sub.y in the composite material was 24%, wherein x was 2.83 and y was 0.56.

Example 6: Preparation of MoS.SUB.x.O.SUB.y./C Nanocomposite Material

(36) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the absorbed dose rate in Example 1 was altered to 150 Gy/min. The mass percentage of MoS.sub.xO.sub.y in the composite material was 20%, wherein x was 2.94 and y was 0.63.

Example 7: Preparation of MoS.SUB.x.O.SUB.y./C Nanocomposite Material

(37) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the absorbed dose rate in Example 1 was altered to 300 Gy/min. The mass percentage of MoS.sub.xO.sub.y in the composite material was 25%, wherein x was 3.07 and y was 0.69.

Example 8: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(38) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the absorbed dose in Example 1 was altered to 150 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 24%, wherein x was 2.81 and y was 0.45.

Example 9: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(39) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the absorbed dose in Example 1 was altered to 300 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 26%, wherein x was 2.69 and y was 0.35.

Example 10: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(40) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the solvent in Example 1 was altered to glycerol. The mass percentage of MoS.sub.xO.sub.y in the composite material was 22%, wherein x was 2.85 and y was 0.33.

Example 11: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(41) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the solvent in Example 1 was altered to deionized water. The mass percentage of MoS.sub.xO.sub.y in the composite material was 24%, wherein x was 2.81 and y was 0.45.

Example 12: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(42) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that 20 mg ammonium tetrathiomolybdate in Example 1 was replaced by 20 mg ammonium molybdate and 30 mg thiourea, and the absorbed dose in Example 1 was altered to 200 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 35%, wherein x was 2.75 and y was 0.33.

Example 13: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(43) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that 20 mg ammonium tetrathiomolybdate in Example 1 was replaced by 20 mg ammonium molybdate and 40 mg thiourea, the absorbed dose rate in Example 1 was altered to 1,000 Gy/min, and the absorbed dose in Example 1 was altered to 200 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 35%, wherein x was 2.72 and y was 0.41.

Example 14: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(44) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that 20 mg ammonium tetrathiomolybdate in Example 1 was replaced by 20 mg sodium molybdate and 40 mg thiourea, the .sup.60Co γ-ray in Example 1 was replaced by an electron beam produced by an electron accelerator with an energy of 0.6 MeV, the absorbed dose rate in Example 1 was altered to 1,000 Gy/min, and the absorbed dose in Example 1 was altered to 200 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 37%, wherein x was 2.75 and y was 0.27.

Example 15: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(45) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that 20 mg ammonium tetrathiomolybdate in Example 1 was replaced by 20 mg sodium molybdate and 60 mg sodium thiosulfate, the .sup.60Co γ-ray in Example 1 was replaced by an electron beam produced by an electron accelerator with an energy of 3 MeV, the absorbed dose rate in Example 1 was altered to 15 kGy/min, and the absorbed dose in Example 1 was altered to 400 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 35%, wherein x was 2.81 and y was 0.28.

Example 16: Preparation of MoS.SUB.x.O.SUB.y./Carbon Nanocomposite Material

(46) The MoS.sub.xO.sub.y/carbon nanocomposite material was prepared under the conditions of Example 1 except that the .sup.60Co γ-ray in Example 1 was replaced by an electron beam produced by an electron accelerator with an energy of 5 MeV, the absorbed dose rate in Example 1 was altered to 30 kGy/min, and the absorbed dose in Example 1 was altered to 200 kGy. The mass percentage of MoS.sub.xO.sub.y in the composite material was 35%, wherein x was 3.10 and y was 0.60.

(47) It should be noted that in each of the above examples, 1 kGy=1000 Gy.

(48) The catalytic performance for electrocatalytic hydrogen evolution reaction of MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Examples 2-16 were tested according to the method and test conditions described in Example 1. The results are recorded in Table 1 together with the test results in Example 1.

(49) TABLE-US-00001 TABLE 1 Comparison of catalytic performances of MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in Examples 1-16 Catalyst Initial Current Corresponding Current density loading overpotential density overpotential.sup.a at η = 300 mV Tafel slope Examples (mg/cm.sup.2) η (mV) j (mA/cm.sup.2) η (mV) j (mA/cm.sup.2) (mV/dec) Example 1 0.275 120 10 160 260 41 Example 2 0.275 120 10 156 272 40 Example 3 0.275 150 10 195 170 56 Example 4 0.275 150 10 193 210 48 Example 5 0.275 162 10 192 152 63 Example 6 0.275 122 10 162 285 39 Example 7 0.275 117 10 154 321 38 Example 8 0.275 121 10 159 304 40 Example 9 0.275 120 10 164 297 42 Example10 0.275 125 10 167 269 41 Example11 0./75 121 10 163 304 42 Example12 0.275 145 10 190 200 57 Example13 0.275 148 10 195 189 58 Example14 0.275 150 10 199 182 60 Example15 0.275 150 10 198 190 60 Example16 0.275 118 10 156 332 38
a, the corresponding overpotential refers to the overpotential when the current density is 10 mA/cm.sup.2 as listed in the previous column; mV/dec represents the value of the change in potential when the current density changes by an order of magnitude, and dec is the abbreviation of decade.

Comparative Examples 1-11

(50) 11 kinds of catalysts for electrocatalytic hydrogen evolution reaction were prepared according to the description of the references in Table 2. The electrocatalytic hydrogen evolution reaction performances of the 11 kinds of catalysts prepared in Comparative Examples 1-11 were tested according to the method and test conditions described in Example 1. The test results are shown in Table 2. The references in Table 2 are incorporated into the present application by reference in their entireties, which are not repeated in this application.

(51) TABLE-US-00002 TABLE 2 Comparison of catalytic performances of the catalysts prepared in Comparative Examples 1-11 Catalyst Initial Current Corresponding Current density Tafel loading overpotential density overpotential.sup.a at η = 300 mV slope Catalyst (mg/cm.sup.2) η (mV) j (mA/cm.sup.2) η (mV) j (mA/cm.sup.2) (mV/dec) References Comparative defect-abundant 0.285 120 13 200 ~80 50 1 Example 1 MoS.sub.2 Comparative amorphous / 150 10 ~00 <100 ~60 2 Example 2 MoS.sub.2 Comparative 1T MoS.sub.2 / / 10 195 150 54 3 Example 3 Comparative MoS.sub.2 with 0.285 90 10 248 20 61 4 Example 4 few layers Comparative 2H-MoS.sub.2 0.205 112 10 214 55 74 5 Example 5 Comparative MoS.sub.2/rGO 0.285 ~100 10 ~155 ~120 41 6 Example 6 Comparative GA-MoS.sub.2 0.56 ~100 10 165 / 41 7 Example 7 Comparative MoS.sub.2 with / 130 10 ~230.sup.b <30 50.sup.b 8 Example 8 high curvature Comparative MoS.sub.2/Au / 90 10 ~225 <50 69 9 Example 9 Comparative Au/MoS.sub.2 0.275 120 10 ~260 30 71 10 Example 10 Comparative MoS.sub.2/rGO 0.20 140 10 ~180 ~130 41 11 Example 11
a, the corresponding overpotential refers to the overpotential when the current density is essentially 10 mA/cm.sup.2 as listed in previous column.
b, these data have been processed by iR-correction.

(52) The references in Table 2 are as follows: 1, Xie J., Zhang H., Li S., Wang R., Sun X., Zhou M., Zhou J., Lou X., Xie Y. Advanced Materials 2013, 25 (40), 5807-5813. 2, Benck J. D., Chen Z., Kuritzky L. Y., Forman A. J., Jaramillo T. F. ACS Catalysis 2012, 2 (9), 1916-1923. 3, Lukowski M. A., Daniel A. S., Meng F., Forticaux A., Li L., Jin S., Journal of the American Chemical Society 2013, 135 (28), 10274-10277. 4, Benson J., Li M., Wang S., Wang P., Papakonstantinou P. ACS Applied Materials & Interfaces 2015, 7 (25), 14113-14122. 5, Guo B., Yu K., Li H., Song H., Zhang Y., Lei X., Fu H., Tan Y., Zhu Z. ACS Applied Materials & Interfaces 2016, 8 (8), 5517-5525. 6, Li Y., Wang H., Xie L., Liang Y., Hong G, Dai H. Journal of the American Chemical Society 2011, 133 (19), 7296-7299. 7, Zhao Y., Xie X., Zhang J., Liu H., Ahn H., Sun K., Wang G Chemistry—A European Journal 2015, 21 (45), 15908-15913. 8, Kibsgaard J., Chen Z., Reinecke B. N., Jaramillo T. F. Nature Materials 2012, 11 (11), 963-969. 9, Wang T., Liu L., Zhu Z., Papakonstantinou P., Hu J., Liu H., Li M. Energy & Environmental Science 2013, 6 (2), 625-633. 10, Shi Y. Wang J., Wang C., Zhai T., Bao W., Xu J., Xia X., Chen H. Journal of the American Chemical Society 2015, 137 (23), 7365-7370. 11, Zheng X., Xu J., Yan K., Wang H., Wang Z., Yang S. Chemistry of Materials 2014, 26 (7), 2344-2353.

(53) By comprehensively analyzing Table 1 and Table 2, it can be known that when the MoS.sub.xO.sub.y/carbon nanocomposite materials prepared in the examples of the present application are used as catalysts for electrocatalytic hydrogen evolution reactions, they have a low Tafel slopes and initial overpotentials, and have large current densities at lower overpotentials. For example, when the materials prepared in Examples 1-16 of the present application are used as catalysts, the current densities at overpotentials of 300 mV are 150 mA/cm.sup.2 or more, the current densities of many examples can reach 200 mA/cm.sup.2 or more, and the better ones can reach 300 mA/cm.sup.2 or more. These performances are comparable to the catalytic performance of the commercial 20% Pt/C catalyst (current density of 370 mA/cm.sup.2 at an overpotential of 300 mV).

(54) For the catalysts prepared in Comparative Examples 1-11, the current densities at an overpotential of 300 mV are significantly lower than that of the present application, and the maximum current density is also less than 150 mA/cm.sup.2. Moreover, their preparation methods are complicated, the material cost is relatively high, and their catalytic performances are limited, which is far from meeting the requirement for practical industrial applications.

(55) In addition, when the materials prepared in the examples of the present application are used as catalysts, the overpotentials at 10 mA/cm.sup.2 are 200 mV or less, and when the materials prepared in Comparative Examples 1-11 are used as catalysts, the overpotentials at 10 mA/cm.sup.2 are mostly 200 mV or higher.

(56) It can be seen that the MoS.sub.xO.sub.y/carbon nanocomposite materials provided by the present application are prepared by a simpler method, lower in cost, and have more excellent catalytic performances than the catalysts prepared in Comparative Examples 1-11, and can meet requirements in the industrial production.

(57) The above description is obtained by only the preferred examples of the present application, and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc., which are made within the spirit and principles of the present application, should be included within the scope of claims of the present application.