A nano-tungsten-molybdenum hydrogen evolution catalyst and its preparation method and application

Abstract

The present invention provides a nano-tungsten-molybdenum hydrogen evolution catalyst, its preparation method, and application. The preparation method comprises the following steps: S1, dispersing conductive carbon black in water to obtain a first mixed slurry; S2, mixing a tungsten salt precursor and a molybdenum salt precursor with water to obtain a mixed solution; then mixing the mixed solution with the first mixed slurry to obtain a second mixed slurry; S3, heating the second mixed slurry to react, followed by drying to obtain an intermediate product; S4, calcining the intermediate product, followed by cooling and grinding to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst. The nano-tungsten-molybdenum hydrogen evolution catalyst of the present invention can effectively solve the problems of poor stability and activity of non-precious metal hydrogen evolution catalysts in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen evolution catalysts, and in particular to a nano-tungsten-molybdenum hydrogen evolution catalyst and a preparation method and application thereof. Background Art

[0002] Currently, the most widely commercialized hydrogen production technology is alkaline water electrolysis. Its operating power is 20-100% of the rated power, with a power response speed of 20% / second. This makes it difficult to directly utilize fluctuating energy sources such as low-power photovoltaic and wind power, resulting in a low renewable energy utilization rate. Furthermore, the electrolyzer contains alkaline solution, which is prone to corrosion and leakage. Proton exchange membrane electrolyzers, on the other hand, offer higher energy efficiency, utilizing renewable energy sources ranging from 0-150% of the rated power. Their power response speed is 100% / second, making them highly compatible with renewable energy and a promising energy storage option for future off-grid distributed power stations. If combined with hydrogen fuel cells, they could be used for energy storage and peak load regulation within future power grids.

[0003] However, hydrogen production through proton exchange membrane electrolysis (PEM) currently faces high initial investment costs, primarily due to the precious metal catalysts in the electrodes. Currently, the cathode catalyst used in PEM electrolyzers is primarily a 20% Pt / C catalyst. Due to the high cost and susceptibility of Pt-based precious metal catalysts to dissolution at high current densities, which reduces PEM electrolyzer performance, the large-scale application of PEM electrolyzers has been limited.

[0004] Current research on non-precious metal hydrogen evolution catalysts primarily focuses on transition metal compounds, including cobalt, molybdenum, nickel, and iron compounds, with nitrogen, phosphorus, oxygen, and sulfur as the primary elements. However, because the anode and cathode of a proton exchange membrane electrolyzer are in an acidic environment, transition metal compounds readily react with the catalyst, shortening its lifespan.

[0005] Patent CN113058620A provides a molybdenum sulfide hydrogen evolution catalyst, its preparation method, and application. It utilizes a liquid phase exfoliation method to exfoliate commercial bulk molybdenum sulfide into nanosheets, which helps expose more edge active sites. The invention uses a chemical oxidation polymerization method to in-situ synthesize polyaniline on molybdenum sulfide nanosheets, which helps prevent secondary agglomeration of the nanosheets. At the same time, the invention uses a thermal decomposition method to convert polyaniline into a carbon material, which helps improve the conductivity of the catalyst. However, its preparation is relatively complex, and it also does not involve the effect of increasing the stability of the catalyst. Summary of the Invention

[0006] The main purpose of the present invention is to provide a nano-tungsten-molybdenum hydrogen evolution catalyst and its preparation method and application, so as to solve the problem of poor stability and activity of non-noble metal hydrogen evolution catalysts in the prior art.

[0007] To achieve the above-mentioned object, according to one aspect of the present invention, a method for preparing a nano-tungsten-molybdenum hydrogen evolution catalyst is provided, the preparation method comprising the following steps: S1, dispersing conductive carbon black in water to obtain a first mixed slurry; S2, mixing a tungsten salt precursor, a molybdenum salt precursor and water to obtain a mixed solution; then mixing the mixed solution with the first mixed slurry to obtain a second mixed slurry; S3, heating the second mixed slurry to react, then drying to obtain an intermediate product; S4, calcining the intermediate product, then cooling and grinding to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0008] Furthermore, the weight ratio of the tungsten salt precursor to the molybdenum salt precursor is 8:1 to 1:8, preferably 4:1 to 1:4.

[0009] Furthermore, the ratio of the weight of the conductive carbon black to the total weight of the tungsten salt precursor and the molybdenum salt precursor is (0.2-0.6): (0.2-0.6).

[0010] Furthermore, in step S3, the reaction temperature is 60-250° C., and the reaction time is 3-48 h; preferably, the reaction temperature is 120-180° C., and the reaction time is 6-15 h.

[0011] Furthermore, the calcination temperature is 800-1200°C and the time is 1-6h; preferably, the heating rate of the calcination is 1-10°C / min; preferably, the calcination is carried out under an inert atmosphere; more preferably, the gas flow rate of the inert atmosphere is 100-1000ml / min.

[0012] Furthermore, the mass concentration of conductive carbon black in the first mixed slurry is 0.05-10wt%, preferably 0.1-5wt%; preferably, the weight ratio of the sum of the weights of the tungsten salt precursor and the molybdenum salt precursor to the mixed solution is (0.01-5):100, preferably (0.3-3):100.

[0013] Furthermore, in step S3, the drying temperature is 60-150° C. and the drying time is 6-48 hours.

[0014] Furthermore, step S1 includes: subjecting the conductive carbon black to ultrasonic treatment and stirring treatment in water in sequence; wherein, the ultrasonic treatment time is 0.5 to 4 hours, preferably 0.5 to 2 hours; the stirring treatment time is 0.5 to 6 hours, preferably 0.5 to 2 hours.

[0015] Furthermore, the tungsten salt precursor includes one or more of phosphotungstic acid, tungsten chloride, and ammonium tungstate; the molybdenum salt precursor includes one or more of ammonium molybdate tetrahydrate, molybdenum acetate, molybdic acid, and potassium molybdate.

[0016] In order to achieve the above object, according to one aspect of the present invention, a nano-tungsten-molybdenum hydrogen evolution catalyst is provided, which is prepared according to the above preparation method.

[0017] According to another aspect of the present invention, there is provided a use of the above-mentioned nano-tungsten-molybdenum hydrogen evolution catalyst in catalyzing proton exchange membrane water electrolysis.

[0018] By applying the technical solution of the present invention, a nano-tungsten-molybdenum hydrogen evolution catalyst was prepared. By compounding a tungsten salt precursor and a molybdenum salt precursor in the precursor stage, more hydrogen evolution active sites are formed, electron transfer is increased, and the hydrogen evolution activity of the catalyst is improved. At the same time, the present invention selects tungsten and molybdenum transition metal-based catalysts, making full use of the characteristics of tungsten and molybdenum compounds with good stability in acidic media, so that the prepared tungsten-molybdenum hydrogen evolution catalyst can avoid problems such as dissolution and rapid decrease in activity in acidic media, and effectively improves the service life of the hydrogen evolution catalyst in the proton exchange membrane electrolyzer. The present invention constructs a system of tungsten, molybdenum, and conductive carbon black composites, wherein the conductive carbon black can not only exert its conductive properties, but also serve as a carrier for the composite of tungsten and molybdenum precursors, providing a larger specific surface area for the formation of tungsten-molybdenum active sites, which is conducive to the dispersion and attachment of tungsten and molybdenum, and provides a sufficient reaction platform for the catalytic reaction. In addition, the conductive carbon black can also form covalent bonds with tungsten and molybdenum, further improving the stability of the catalyst. In summary, the nano-tungsten-molybdenum catalyst provided by the present invention has low cost, simple process, and good stability and hydrogen evolution activity in the acidic medium of the proton exchange membrane electrolyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 A schematic diagram of the hydrogen evolution overpotential according to Example 2 is shown. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] In order to solve the above-mentioned problems in the prior art, according to one aspect of the present invention, a method for preparing a nano-tungsten-molybdenum hydrogen evolution catalyst is provided, which comprises the following steps: S1, dispersing conductive carbon black in water to obtain a first mixed slurry; S2, mixing a tungsten salt precursor, a molybdenum salt precursor and water to obtain a mixed solution; then mixing the mixed solution with the first mixed slurry to obtain a second mixed slurry; S3, heating the second mixed slurry to react, and then drying to obtain an intermediate product; S4, calcining the intermediate product, and then cooling and grinding to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0023] The present invention forms more hydrogen evolution active sites and increases electron transfer by compounding tungsten salt precursors and molybdenum salt precursors in the precursor stage, thereby improving the hydrogen evolution activity of the catalyst. At the same time, the present invention selects tungsten and molybdenum transition metal-based catalysts, making full use of the characteristics of tungsten and molybdenum compounds with good stability in acidic media, so that the prepared tungsten-molybdenum hydrogen evolution catalyst can avoid problems such as being dissolved in acidic media and rapid decrease in activity, effectively improving the service life of the hydrogen evolution catalyst in the proton exchange membrane electrolyzer. The present invention constructs a system of tungsten, molybdenum, and conductive carbon black composites, wherein the conductive carbon black can not only exert its conductive properties, but also can serve as a carrier for the composite of tungsten and molybdenum precursors, providing a larger specific surface area for the formation of tungsten-molybdenum active sites, which is conducive to the dispersion and attachment of tungsten and molybdenum, and providing a sufficient reaction platform for the catalyst reaction. In addition, conductive carbon black can also form covalent bonds with tungsten and molybdenum, further improving the stability of the catalyst. In summary, the nano tungsten-molybdenum catalyst provided by the present invention is low in cost, simple in process, and has good stability and hydrogen evolution activity in the acidic medium of the proton exchange membrane electrolyzer.

[0024] In order to better increase the activity of the hydrogen evolution catalyst, in a preferred embodiment, the weight ratio of the tungsten salt precursor to the molybdenum salt precursor is 8:1 to 1:8, preferably 4:1 to 1:4. When the amount of the tungsten salt precursor added is high, a portion of tungsten carbide will be formed, which has lower activity than the tungsten-molybdenum-based catalyst and a decreased performance; when the amount of the molybdenum salt precursor added is high, a portion of molybdenum carbide will be formed, which has lower activity than the tungsten-molybdenum-based catalyst and a decreased performance. Within the appropriate ratio range, the tungsten-molybdenum mixed catalyst is beneficial to enhancing the conductivity of the catalyst and its relationship with the carrier, thereby promoting hydrogen evolution activity. Within the above-mentioned preferred weight ratio of tungsten salt to molybdenum salt precursor, a hydrogen evolution catalyst with good hydrogen evolution activity and stability can be prepared. If the above ratio is exceeded, it is less conducive to the activity and stability of the catalyst.

[0025] In a preferred embodiment, the ratio of the weight of the conductive carbon black to the total weight of the tungsten salt precursor and the molybdenum salt precursor is (0.2-0.6):(0.2-0.6). The above ratio is preferred because it can better adjust the ratio of carbon, tungsten, and molybdenum, so that the tungsten and molybdenum loading on the conductive carbon black is better achieved. It is also more conducive to the formation of covalent bonds between tungsten, molybdenum and the conductive carbon black, thereby achieving better hydrogen evolution activity and stability.

[0026] In order to better compound the tungsten salt precursor and the molybdenum salt precursor on the conductive carbon black in the solution reaction stage, in a preferred embodiment, the reaction temperature in step S3 is 60-250°C and the time is 3-48 hours; preferably, the reaction temperature is 120-180°C and the time is 6-15 hours.

[0027] In order to better solidify the active sites of tungsten and molybdenum composites on the conductive carbon black, in a preferred embodiment, the calcination temperature is 800-1200°C and the time is 1-6 hours; the heating rate of the calcination is preferably 1-10°C / min; the calcination is preferably carried out under an inert atmosphere; and the gas flow rate of the inert atmosphere is more preferably 100-1000 mL / min. Calcination according to the above preferred conditions can better form a tungsten-molybdenum mixed covalent carbide during the calcination process, so that a portion of the tungsten salt forms tungsten carbide with the conductive carbon black, and a portion of the molybdenum salt forms molybdenum carbide with the conductive carbon black, which is more conducive to the formation of covalent bonds, thereby further improving the stability of the hydrogen evolution catalyst.

[0028] In order to better disperse the raw materials, in a preferred embodiment, the mass concentration of the conductive carbon black in the first mixed slurry is 0.05-10wt%, preferably 0.1-5wt%; preferably, the weight ratio of the sum of the weights of the tungsten salt precursor and the molybdenum salt precursor to the mixed solution is (0.1-5):100, preferably (0.3-3):100.

[0029] In actual operation, the operator can preferably use a syringe pump, peristaltic pump, or other device to titrate the mixed solution into the first mixed slurry, more preferably while continuously stirring. The titration rate is preferably 0.05-0.5 mL / min. The above conditions are preferred because they are more conducive to fully dispersing the raw materials in the slurry system and more fully generating active sites.

[0030] In a preferred embodiment, the drying temperature in step S3 is 60-150° C. and the drying time is 6-48 hours. The above-mentioned drying conditions are preferred to better load the tungsten and molybdenum active sites on the surface of the conductive carbon black, making the intermediate product more suitable for subsequent calcination treatment.

[0031] In order to further fully disperse the conductive carbon black in the first mixed slurry, in a preferred embodiment, step S1 includes: subjecting the conductive carbon black to ultrasonic treatment and stirring treatment in water in sequence; wherein the ultrasonic treatment time is 0.5 to 4 hours, preferably 0.5 to 2 hours; the stirring treatment time is 0.5 to 6 hours, preferably 0.5 to 2 hours.

[0032] In order to better form tungsten-molybdenum active sites and better realize the formation of covalent bonds between tungsten, molybdenum and conductive carbon black, in a preferred embodiment, the tungsten salt precursor includes one or more of phosphotungstic acid, tungsten chloride, and ammonium tungstate; the molybdenum salt precursor includes one or more of ammonium molybdate tetrahydrate, molybdenum acetate, molybdic acid, and potassium molybdate.

[0033] In actual operation, the conductive carbon black can be conventional commercially available types, such as BP2000 and VXC-72R, but is not limited to the types listed above.

[0034] According to another aspect of the present invention, a nano-tungsten-molybdenum hydrogen evolution catalyst is provided, which is prepared according to the above-mentioned preparation method. The nano-tungsten-molybdenum hydrogen evolution catalyst of the present invention is low in cost and has both excellent hydrogen evolution activity and stability.

[0035] According to another aspect of the present invention, a method for using the aforementioned nano-tungsten-molybdenum hydrogen evolution catalyst in catalytic proton exchange membrane water electrolysis is provided. The nano-tungsten-molybdenum hydrogen evolution catalyst of the present invention is low-cost, exhibits excellent hydrogen evolution activity and stability, and is suitable for use in catalytic proton exchange membrane water electrolysis.

[0036] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0037] Example 1

[0038] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0039] Weigh 0.32 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0040] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0041] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0042] The hydrogen evolution catalyst was prepared with ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -249mV.

[0043] Example 2

[0044] Weigh 0.6 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 4 hours, then place the mixed solution in an electromagnetic stirrer and stir for 6 hours until it is fully dispersed to obtain a first mixed slurry.

[0045] Weigh 0.23 g of phosphotungstic acid and 0.17 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 23:17), measure 40 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0046] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 180° C. for 12 h, and then placed in a forced air drying oven at 100° C. for 12 h to obtain an intermediate product.

[0047] The intermediate product was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 1000° C. and kept warm for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0048] The hydrogen evolution catalyst was prepared with ink and the overpotential of the hydrogen evolution catalyst was tested using a three-electrode system. The result was -190mV. Figure 1 shown.

[0049] Example 3

[0050] Weigh 0.4 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 1 hour, then place the mixed solution in an electromagnetic stirrer and stir for 3 hours until it is fully dispersed to obtain a first mixed slurry.

[0051] Weigh 0.13 g of phosphotungstic acid and 0.28 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 13:28), measure 20 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0052] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 120° C. for 12 h, and then placed in a forced air drying oven at 120° C. for 12 h to obtain an intermediate product.

[0053] The intermediate product was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 800° C. and kept warm for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0054] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -250 mV.

[0055] Example 4

[0056] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0057] Weigh 0.32 g of chloride and 0.08 g of molybdenum acetate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, then add chloride and platinum acetate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, stirring continuously during the addition process to obtain a second mixed slurry.

[0058] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0059] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0060] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -223mV.

[0061] Example 5

[0062] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0063] Weigh 0.64 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 8:1), measure 60 mL of deionized water, and then add chloride and platinum acetate to the deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, stirring continuously during the addition process to obtain a second mixed slurry.

[0064] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0065] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0066] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -229 mV.

[0067] Example 6

[0068] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0069] Weigh 0.01 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 1:8), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, stirring continuously during the addition process to obtain a second mixed slurry.

[0070] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0071] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0072] The hydrogen evolution catalyst was prepared with ink, and the overpotential of the hydrogen evolution catalyst was tested using a three-electrode system. The result was -210 mV. Example 7

[0073] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0074] Weigh 0.72 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 9:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0075] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0076] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0077] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -320mV.

[0078] Example 8

[0079] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0080] Weigh 0.32 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0081] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 60° C. for 48 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0082] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0083] The hydrogen evolution catalyst was prepared with ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -256mV.

[0084] Example 9

[0085] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0086] Weigh 0.32 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0087] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 250° C. for 3 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0088] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0089] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -278mV.

[0090] Example 10

[0091] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0092] Weigh 0.32 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate to deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, and continuously stir during the addition to obtain a second mixed slurry.

[0093] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0094] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 1200° C. and kept warm for 1 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0095] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -210 mV.

[0096] Comparative Example 1

[0097] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0098] Weigh 0.32 g of phosphotungstic acid, measure 60 mL of deionized water, then add phosphotungstic acid and ammonium molybdate tetrahydrate into the deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, stirring continuously during the addition process to obtain a second mixed slurry.

[0099] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0100] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0101] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -320mV.

[0102] Comparative Example 2

[0103] Weigh 0.2 g of VXC-72R conductive carbon black, measure 50 mL of deionized water, then add VXC-72R conductive carbon black to the deionized water, place it in an ultrasonic container and ultrasonicate for 2 hours, then place the mixed solution in an electromagnetic stirrer and stir for 2 hours until it is fully dispersed to obtain a first mixed slurry.

[0104] Weigh 0.08 g of ammonium molybdate tetrahydrate, measure 60 mL of deionized water, then add phosphotungstic acid and ammonium molybdate tetrahydrate into the deionized water and stir for 0.5 h until completely dissolved to obtain a mixed solution, and then slowly add the mixed solution dropwise to the first mixed slurry through a syringe pump, stirring continuously during the addition process to obtain a second mixed slurry.

[0105] The second mixed slurry was added into a reactor with a polytetrafluoroethylene lining, reacted at 150° C. for 12 h, and then placed in a forced air drying oven at 80° C. for 24 h to obtain an intermediate product.

[0106] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0107] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -268mV.

[0108] Comparative Example 3

[0109] Weigh 0.32 g of phosphotungstic acid and 0.08 g of ammonium molybdate tetrahydrate (the weight ratio of tungsten salt to molybdenum salt precursor is 4:1), measure 60 mL of deionized water, and then add phosphotungstic acid and ammonium molybdate tetrahydrate into the deionized water and stir for 0.5 h until they are completely dissolved to obtain a mixed solution.

[0110] The mixed slurry was added into a reactor lined with polytetrafluoroethylene, reacted at 150°C for 12 hours, and then placed in a forced air drying oven at 80°C for 24 hours to obtain an intermediate product.

[0111] The intermediate product in step (4) was placed in a ceramic boat and transferred to a tube furnace. Under an argon atmosphere with an atmosphere flow rate of 300 mL / min, the calcination temperature was raised to 900° C. and kept at this temperature for 2 h to obtain a nano-tungsten-molybdenum hydrogen evolution catalyst.

[0112] The hydrogen evolution catalyst was prepared into ink, and the overpotential of the hydrogen evolution catalyst was electrochemically tested using a three-electrode system, and the result was -410 mV.

[0113] Comparative Example 4

[0114] Commercially available molybdenum carbide has a CAS number of 12069-89-5, and commercially available tungsten carbide has a CAS number of 12070-12-1.

[0115] The overpotential of commercial molybdenum carbide and commercial tungsten carbide was tested electrochemically using a three-electrode system, and the results were 610 mV respectively.

[0116] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0117] The nano-tungsten-molybdenum hydrogen evolution catalyst prepared in the present invention has excellent hydrogen evolution activity. In particular, the hydrogen evolution catalyst prepared under the preferred conditions of the present invention has a hydrogen evolution overpotential of -190 mV, which is significantly improved compared to the commercial tungsten carbide and molybdenum carbide in Comparative Example 4.

[0118] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-tungsten-molybdenum hydrogen evolution catalyst, characterized in that: The preparation method comprises the following steps: S1, dispersing conductive carbon black in water to obtain a first mixed slurry; S2, mixing a tungsten salt precursor, a molybdenum salt precursor and water to obtain a mixed solution; then mixing the mixed solution with the first mixed slurry to obtain a second mixed slurry; S3, heating the second mixed slurry to react, and then drying to obtain an intermediate product; S4, calcining the intermediate product, followed by cooling and grinding to obtain the nano-tungsten-molybdenum hydrogen evolution catalyst; In step S3, the reaction temperature is 120-180° C. and the reaction time is 6-15 hours; The calcination temperature is 800-1200°C and the time is 1-6 hours; The weight ratio of the tungsten salt precursor to the molybdenum salt precursor is 8:1~1:8; the ratio of the weight of the conductive carbon black to the total weight of the tungsten salt precursor and the molybdenum salt precursor is (0.2~0.6): (0.2~0.6).

2. The preparation method according to claim 1, characterized in that The weight ratio of the tungsten salt precursor to the molybdenum salt precursor is 4:1 to 1:

4.

3. The preparation method according to claim 1, characterized in that The heating rate of the calcination treatment is 1-10°C / min.

4. The preparation method according to claim 1, characterized in that The calcination treatment is performed under an inert atmosphere.

5. The preparation method according to claim 4, characterized in that The gas flow rate of the inert atmosphere is 100-1000 ml / min.

6. The preparation method according to any one of claims 1 to 5, characterized in that The mass concentration of the conductive carbon black in the first mixed slurry is 0.05-10 wt %.

7. The preparation method according to claim 6, characterized in that The mass concentration of the conductive carbon black in the first mixed slurry is 0.1-5 wt %.

8. The preparation method according to any one of claims 1 to 5, characterized in that The weight ratio of the sum of the weights of the tungsten salt precursor and the molybdenum salt precursor to the mixed solution is (0.01-5):

100.

9. The preparation method according to claim 8, characterized in that The weight ratio of the sum of the weights of the tungsten salt precursor and the molybdenum salt precursor to the mixed solution is (0.3-3):

100.

10. The preparation method according to any one of claims 1 to 5, characterized in that The drying temperature in step S3 is 60-150° C. and the drying time is 6-48 hours.

11. The preparation method according to any one of claims 1 to 5, characterized in that The step S1 comprises: subjecting the conductive carbon black to ultrasonic treatment and stirring treatment in water in sequence; wherein the ultrasonic treatment time is 0.5 to 4 hours; and the stirring treatment time is 0.5 to 6 hours.

12. The preparation method according to claim 11, characterized in that The ultrasonic treatment time is 0.5~2h.

13. The preparation method according to claim 11, characterized in that The stirring time is 0.5 to 2 hours.

14. The preparation method according to any one of claims 1 to 5, characterized in that The tungsten salt precursor includes one or more of phosphotungstic acid, tungsten chloride, and ammonium tungstate; the molybdenum salt precursor includes one or more of ammonium molybdate tetrahydrate, molybdenum acetate, molybdic acid, and potassium molybdate.

15. A nano-tungsten-molybdenum hydrogen evolution catalyst prepared according to the preparation method according to any one of claims 1 to 14.

16. Use of the nano-tungsten-molybdenum hydrogen evolution catalyst according to claim 15 in catalyzing proton exchange membrane water electrolysis.

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