Highly conductive molybdenum disulfide nanosheet catalyst and method of making same
By introducing transition metal atoms Cr and Sc, and utilizing localized electronic and defect effects, a highly conductive molybdenum disulfide nanosheet catalyst was prepared, solving the problem of insufficient conductivity. This resulted in a high-performance and low-cost catalyst for hydrogen production through water electrolysis, suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGCHUN INSTITUTE OF APPLIED CHEMISTRY CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2023-03-13
- Publication Date
- 2026-05-29
AI Technical Summary
The existing molybdenum disulfide catalysts have insufficient conductivity, which makes it difficult for electrons to transfer rapidly on their surface, limiting their efficient application in hydrogen production by water electrolysis. Furthermore, the existing preparation methods are complex and cannot be mass-produced.
By mixing molybdenum salt, chromium salt, and thiourea to form a first composite support, and then dispersing it in water and reacting it under sealed conditions, a highly conductive molybdenum disulfide nanosheet catalyst was prepared, which improved electron transfer efficiency by utilizing localized electronic effects and defect effects.
The prepared molybdenum disulfide nanosheet catalyst has a good layered structure and uniform dispersion, excellent performance, and lower cost than commercial platinum-based catalysts, making it suitable for large-scale industrial production.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, and more particularly to a highly conductive molybdenum disulfide nanosheet catalyst and its preparation method. Background Technology
[0002] Currently, platinum-based catalysts are used as commercial cathode catalysts for water electrolysis to produce hydrogen. Their high cost and scarce reserves limit their industrial application. Molybdenum disulfide (MoS2) is considered a low-cost solution for water electrolysis cathode catalysts due to its unique electronic structure, which imparts hydrogen evolution activity, its layered structure, high specific surface area, and excellent stability. However, its conductivity is insufficient. Natural MoS2 is a semiconductor, and electrons are difficult to transfer rapidly on its surface. This is the main reason why MoS2 catalysts cannot achieve efficient performance in their service life.
[0003] Currently, the main method to improve the conductivity of MoS2 is coupling it with a highly conductive substrate, most commonly carbon-based materials such as graphene, carbon nanotubes, and amorphous carbon. However, this method often leads to heterogeneous interfaces and structural instability. The strong chemical interaction between the catalyst and the conductive substrate causes it to grow at confined sites, forming multiphase interfaces that are difficult to maintain, resulting in unpredictable effects on catalyst activity. More importantly, in practical applications with high current densities, the dissolution of the carbon-based substrate and the accompanying dissolution of active sites can also cause severe activity degradation.
[0004] Furthermore, catalyst screening was predicted using volcano maps constructed from hydrogen adsorption energy (Han, X.; Tong, X.; Liu, X.; Chen, A.; Wen, X.; Yang, N.; Guo, X., Hydrogen Evolution Reaction on Hybrid Catalysts of Vertical MoS2 Nanosheets and Hydrogenated Graphene. ACS Catalysis 2018, 8(3), 1828-1836.), which showed limited applicability to molybdenum disulfide nanosheet catalysts (Wang, Z.; Tang, MT; Cao, A.; Chan, K.; JK, Insights into the Hydrogen Evolution Reaction on 2D Transition-Metal Dichalcogenides. The Journal of Physical Chemistry C2022, 126(11), 5151-5158.). Therefore, a new method is urgently needed to prepare a highly conductive molybdenum disulfide nanosheet catalyst. Summary of the Invention
[0005] In view of this, the purpose of this invention is to solve the technical problems of low efficiency in the existing Sabatier strategy for finding low-cost catalysts, neglecting the kinetic influence mainly based on conductivity, resulting in excessive energy consumption for water electrolysis in service state and making it unusable, and the complex preparation method of the catalyst, which makes it impossible to mass-produce. The invention provides a method for preparing a molybdenum disulfide nanosheet catalyst with high conductivity.
[0006] This invention provides a method for preparing a highly conductive molybdenum disulfide nanosheet catalyst, comprising the following steps:
[0007] 1) A first composite carrier is obtained by mixing molybdenum salt, chromium salt and thiourea.
[0008] 2) Disperse the first composite carrier in water to obtain a suspension of the first composite carrier;
[0009] 3) React the first composite carrier suspension under sealed conditions, and then process the resulting product to obtain the second composite carrier.
[0010] 4) The second composite support and scandium metal salt are dispersed in water and reacted to obtain a highly conductive molybdenum disulfide nanosheet catalyst.
[0011] In this invention, the molar ratio of molybdenum salt to chromium salt in step 1) is 5:1 to 50:1;
[0012] The molar ratio of the thiourea to the metallic chromium salt is 10:1 to 100:1;
[0013] In step 4), the mass ratio of scandium metal salt to the second composite carrier is 1:20 to 1:2.
[0014] In step 2), the ratio of the first composite carrier to water is (0.5-5) g: (10-100) mL.
[0015] In this invention, the reaction temperature under the sealed conditions is 150–240°C, and the reaction time is 18–36 h.
[0016] In this invention, the molybdenum salt is ammonium molybdate, the chromium salt is chromium nitrate, and the scandium salt is scandium nitrate.
[0017] In this invention, the product post-processing in step 3) includes:
[0018] The product is centrifuged, washed, dried, and ground.
[0019] The washing is performed 3 to 5 times; the washing uses a mixture of ethanol and water, and the volume ratio of ethanol to water is 1:10 to 1:1.
[0020] The drying temperature is 50–70°C, and the drying time is 8–24 hours.
[0021] The grinding time is 5 to 10 minutes.
[0022] In this invention, the dispersion method in steps 2) and 4) is ultrasonic dispersion.
[0023] In this invention, the reaction temperature in step 4) is 60–150°C, and the reaction time is 8–24 h.
[0024] In this invention, the product obtained in step 4) is subjected to vacuum filtration and drying, and the drying temperature is 40-80°C and the drying time is 4-24 hours.
[0025] This invention provides a highly conductive molybdenum disulfide nanosheet catalyst, prepared by the method described in the above technical solution;
[0026] The nanosheet catalyst contains Mo, S, Cr and Sc elements.
[0027] This invention provides a method for preparing a highly conductive molybdenum disulfide nanosheet catalyst, comprising the following steps: 1) mixing molybdenum salt, chromium salt, and thiourea to obtain a first composite support; 2) dispersing the first composite support in water to obtain a first composite support suspension; 3) reacting the first composite support suspension under sealed conditions, and post-processing the obtained product to obtain a second composite support; 4) dispersing the second composite support and scandium salt in water and reacting to obtain a highly conductive molybdenum disulfide nanosheet catalyst. The molybdenum disulfide nanosheet catalyst prepared by this invention introduces transition metal atoms (such as Cr and Sc), utilizing the localized electronic and defect effects generated in molybdenum disulfide to create more charge carriers, enabling efficient electron transfer within the molybdenum disulfide nanosheet catalyst and improving the intrinsic conductivity of the catalyst; the prepared catalyst exhibits good performance, a well-defined layered structure, and uniform dispersion; and compared to existing commercial platinum-based catalysts, this catalyst has a lower cost. Attached Figure Description
[0028] Figure 1 The results of scanning electron microscopy of the Cr-Sc-MoS2 nanosheet catalyst in Example 1 of this invention;
[0029] Figure 2 The elemental distribution results of the Cr-Sc-MoS2 nanosheet catalyst in Example 1 of this invention are shown below.
[0030] Figure 3 The XRD results are for the Cr-Sc-MoS2 nanosheet catalyst in Example 1 of this invention.
[0031] Figure 4 The XPS results are for the Cr-Sc-MoS2 nanosheet catalyst in Example 1 of this invention;
[0032] Figure 5 The linear sweep voltammetric polarization curve of the Cr-Sc-MoS2 nanosheet catalyst in acidic medium in Example 1 of this invention is shown.
[0033] Figure 6 The linear sweep voltammetric polarization curve of the Cr-Sc-MoS2 nanosheet catalyst in acidic medium in Example 2 of this invention is shown.
[0034] Figure 7 The linear sweep voltammetric polarization curve of the Cr-Sc-MoS2 nanosheet catalyst in acidic medium in Example 3 of this invention is shown. Detailed Implementation
[0035] This invention provides a method for preparing a highly conductive molybdenum disulfide nanosheet catalyst, comprising the following steps:
[0036] 1) A first composite carrier is obtained by mixing molybdenum salt, chromium salt and thiourea.
[0037] 2) Disperse the first composite carrier in water to obtain a suspension of the first composite carrier;
[0038] 3) React the first composite carrier suspension under sealed conditions, and then process the resulting product to obtain the second composite carrier.
[0039] 4) The second composite support and scandium metal salt are dispersed in water and reacted to obtain a highly conductive molybdenum disulfide nanosheet catalyst.
[0040] The method provided by this invention is simple, environmentally friendly, and suitable for large-scale industrial production, producing hundreds of grams of catalysts, laying the foundation for the mass production of non-precious metal catalysts. The molybdenum disulfide nanosheet catalyst prepared by this invention introduces transition metal atoms (such as Cr and Sc), utilizing the localized electronic and defect effects generated in molybdenum disulfide to create more charge carriers, enabling efficient electron transfer within the molybdenum disulfide nanosheet catalyst and improving its intrinsic conductivity. The prepared catalyst exhibits good performance, a well-defined layered structure, and uniform dispersion. Compared to existing commercial platinum-based catalysts, this catalyst is also more cost-effective.
[0041] This invention involves mixing a molybdenum salt, a chromium salt, and a thiourea to obtain a first composite carrier. The mixing of the molybdenum salt, chromium salt, and thiourea is performed at room temperature. The molybdenum salt is ammonium molybdate, and the chromium salt is chromium nitrate. The molar ratio of the molybdenum salt to the chromium salt is 5:1 to 50:1; the molar ratio of the thiourea to the chromium salt is 10:1 to 100:1.
[0042] This invention disperses the first composite carrier in water to obtain a first composite carrier suspension. The ratio of the first composite carrier to water is (0.5-5) g:(10-100) mL; the mass of the first composite carrier is the sum of the masses of the molybdenum salt, the chromium salt, and the thiourea; in specific embodiments, the ratio of the first composite carrier to water is 1.6638 g:30 mL, or 1.5182 g:30 mL, or 1.8683 g:30 mL. The first composite carrier is dispersed in water by ultrasonic dispersion.
[0043] In this invention, the first composite carrier suspension is reacted under sealed conditions, and the resulting product is then processed to obtain a second composite carrier. The reaction under sealed conditions is carried out at a temperature of 150–240°C for a time of 18–36 hours. Preferably, a stainless steel autoclave is used as the sealing device in this invention.
[0044] In this invention, the product post-processing includes:
[0045] The product is centrifuged, washed, dried, and ground.
[0046] The washing is performed 3 to 5 times; the washing uses a mixture of ethanol and water, and the volume ratio of ethanol to water is 1:10 to 1:1.
[0047] The drying temperature is 50–70°C, and the drying time is 8–24 hours.
[0048] The grinding time is 5 to 10 minutes to obtain the second composite carrier.
[0049] After obtaining the second composite support, the present invention disperses the second composite support and a scandium metal salt in water and reacts them to obtain a highly conductive molybdenum disulfide nanosheet catalyst. The scandium metal salt is preferably scandium nitrate. The mass ratio of the scandium metal salt to the second composite support is 1:20 to 1:2; in specific embodiments, the mass ratio of the scandium metal salt to the second composite support is 1:4, 1:12, or 1:2. The second composite support and the scandium metal salt are dispersed in water by ultrasonic dispersion. In the present invention, the reaction temperature is 60–150°C, and the reaction time is 8–24 h. The product obtained from the reaction is subjected to vacuum filtration and drying at a temperature of 40–80°C for 4–24 h.
[0050] This invention provides a highly conductive molybdenum disulfide nanosheet catalyst, prepared by the method described in the above technical solution;
[0051] The nanosheet catalyst contains Mo, S, Cr and Sc elements.
[0052] In a specific embodiment of the present invention, the highly conductive molybdenum disulfide nanosheet catalyst is a Cr-Sc-MoS2 nanosheet catalyst.
[0053] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a highly conductive molybdenum disulfide nanosheet catalyst and its preparation method, should not be construed as limiting the scope of protection of the present invention.
[0054] Example 1
[0055] At room temperature, 1.035 g of CH4N2S and 0.5213 g of (NH4)6Mo7O were added. 24 ·4H2O and 0.1075g of Cr(NO3)3·9H2O were mixed to obtain the first composite support. The first composite support was added to 30ml of deionized water and sonicated for 90min to obtain the first suspension. The first suspension was then transferred to a 50ml Teflon-lined stainless steel autoclave and heated at 180℃ for 24 hours. After cooling to room temperature, the second suspension was obtained. The second suspension was washed with deionized water and ethanol and centrifuged 4 times. The centrifuged product was dried in a drying oven for 12h. The obtained solid was ground for 7 minutes to obtain the second composite support. 60mg of the second composite support and 15mg of Sc(NO3)3·xH2O were mixed with 50ml of deionized water in a 100ml round-bottom flask and sonicated for 90min to disperse evenly. The mixture was reacted at 90℃ for 12h to obtain the third suspension. After filtration, washing with water, and drying, the molybdenum disulfide nanosheet catalyst was obtained.
[0056] The present invention uses scanning electron microscopy to observe the molybdenum disulfide nanosheet catalyst prepared in Example 1, and the results are as follows: Figure 1 As shown, the molybdenum disulfide catalyst prepared in Example 1 has a good layered structure.
[0057] The elemental distribution of the molybdenum disulfide nanosheet catalyst prepared in Example 1 was observed, and the results are as follows: Figure 2 As shown, the molybdenum disulfide catalyst in Example 1 has a uniform elemental distribution, with Mo, S, Cr, and Sc elements all uniformly distributed on the nanosheets.
[0058] The molybdenum disulfide nanosheet catalyst prepared in Example 1 was analyzed by X-ray diffraction, and the results are as follows: Figure 3As shown, the XRD results indicate that the catalyst obtained is molybdenum disulfide, and the peak values correspond to the standard peak values.
[0059] The molybdenum disulfide nanosheet catalyst prepared in Example 1 was analyzed by X-ray photoelectron spectroscopy, and the results are as follows: Figure 4 As shown, the XPS results further confirm that element Cr was successfully introduced into the molybdenum disulfide catalyst in the form of +3 oxidation state.
[0060] The present invention performs linear sweep voltammetric polarization tests on the molybdenum disulfide nanosheet catalyst prepared in Example 1, and the results are as follows: Figure 5 As shown, the Cr-Sc-MoS2 catalyst exhibits excellent electrochemical performance at 10 mA / cm². -2 The overpotential at the current density is only 177mV.
[0061] Example 2
[0062] At room temperature, 0.9825 g of CH4N2S and 0.4522 g of (NH4)6Mo7O were added. 24 ·4H2O and 0.0835g of Cr(NO3)3·9H2O were mixed to obtain the first composite support. The first composite support was added to 30ml of deionized water and sonicated for 90min to obtain the first suspension. The first suspension was then transferred to a 50ml Teflon-lined stainless steel autoclave and heated at 200℃ for 24 hours. After cooling to room temperature, the second suspension was obtained. The second suspension was washed with deionized water and ethanol and centrifuged 4 times. The centrifuged product was dried in a drying oven for 12h. The obtained solid was ground for 6 minutes to obtain the second composite support. 60mg of the second composite support and 5mg of Sc(NO3)3·xH2O were mixed with 50ml of deionized water in a 100ml round-bottom flask and sonicated for 90min to disperse evenly. The mixture was reacted at 90℃ for 12h to obtain the third suspension. After filtration, washing with water, and drying, the molybdenum disulfide nanosheet catalyst was obtained.
[0063] The present invention performs linear sweep voltammetric polarization tests on the molybdenum disulfide nanosheet catalyst prepared in Example 2, and the results are as follows: Figure 6 As shown, the electrochemical performance of the Cr-Sc-MoS2 catalyst is as follows: at 10 mA / cm², -2 The overpotential at the current density is 251mV.
[0064] Example 3
[0065] At room temperature, 1.125 g of CH4N2S and 0.5825 g of (NH4)6Mo7O were added. 240.1608 g of Cr(NO3)3·9H2O was mixed with 4H2O to obtain the first composite support. The first composite support was added to 30 ml of deionized water and sonicated for 90 min to obtain the first suspension. The first suspension was then transferred to a 50 ml Teflon-lined stainless steel autoclave and heated at 160 °C for 24 h. After cooling to room temperature, the second suspension was obtained. The second suspension was washed with deionized water and ethanol and centrifuged 4 times. The centrifuged product was dried in a drying oven for 12 h. The obtained solid was ground for 9 min to obtain the second composite support. 60 mg of the second composite support and 30 mg of Sc(NO3)3·xH2O were mixed with 50 ml of deionized water in a 100 ml round-bottom flask and sonicated for 90 min to disperse evenly. The mixture was reacted at 90 °C for 12 h to obtain the third suspension. After filtration, washing with water, and drying, the molybdenum disulfide nanosheet catalyst was obtained.
[0066] The present invention performs linear sweep voltammetric polarization tests on the molybdenum disulfide nanosheet catalyst prepared in Example 3, and the results are as follows: Figure 7 As shown, the electrochemical performance of the Cr-Sc-MoS2 catalyst is as follows: at 10 mA / cm², -2 The overpotential at the current density is 229mV.
[0067] As shown in the above embodiments, the present invention provides a method for preparing a highly conductive molybdenum disulfide nanosheet catalyst, comprising the following steps: 1) mixing molybdenum salt, chromium salt, and thiourea to obtain a first composite support; 2) dispersing the first composite support in water to obtain a first composite support suspension; 3) reacting the first composite support suspension under sealed conditions, and post-processing the obtained product to obtain a second composite support; 4) dispersing the second composite support and scandium salt in water and reacting to obtain a highly conductive molybdenum disulfide nanosheet catalyst. The molybdenum disulfide nanosheet catalyst prepared by the present invention introduces transition metal atoms (such as Cr and Sc), utilizing the localized electronic and defect effects generated in molybdenum disulfide to create more charge carriers, enabling efficient electron transfer within the molybdenum disulfide nanosheet catalyst and improving the intrinsic conductivity of the catalyst; the prepared catalyst exhibits good performance, a well-defined layered structure, and uniform dispersion; compared with existing commercial platinum-based catalysts, this catalyst has a lower cost.
[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a highly conductive molybdenum disulfide nanosheet catalyst, comprising the following steps: 1) A first composite carrier is obtained by mixing ammonium molybdate (a molybdenum salt), chromium nitrate (a chromium salt), and thiourea. 2) The first composite carrier is ultrasonically dispersed in water to obtain a suspension of the first composite carrier; 3) The first composite carrier suspension is reacted under sealed conditions, and the resulting product is post-processed to obtain the second composite carrier; the reaction temperature under sealed conditions is 150-240℃, and the reaction time is 18-36h. The post-processing of the product includes: centrifuging, washing, drying and grinding the product; the washing is performed 3 to 5 times. The washing process uses a mixture of ethanol and water, with a volume ratio of ethanol to water of 1:10 to 1:1; the drying temperature is 50 to 70°C, and the drying time is 8 to 24 hours; the grinding time is 5 to 10 minutes. 4) The second composite support and scandium nitrate were ultrasonically dispersed in water and reacted to obtain a highly conductive molybdenum disulfide nanosheet catalyst; the mass ratio of scandium nitrate to the second composite support was 1:20 to 1:2; the reaction temperature was 60 to 150°C and the reaction time was 8 to 24 h. The nanosheet catalyst is a Cr-Sc-MoS2 nanosheet catalyst.
2. The preparation method according to claim 1, characterized in that, In step 1), the molar ratio of molybdenum salt to chromium salt is 5:1 to 50:
1. The molar ratio of the thiourea to the metallic chromium salt is 10:1 to 100:
1.
3. The preparation method according to claim 1, characterized in that, In step 2), the ratio of the first composite carrier to water is (0.5-5) g: (10-100) mL.
4. The preparation method according to claim 1, characterized in that, The product obtained in step 4) is subjected to vacuum filtration and drying at a temperature of 40–80°C for 4–24 hours.