A method for preparing and applying nano- and micro-structured MoS2 spheres containing 1T phase.

Abstract

The application relates to a preparation method and application of a nano-micro-structure MoS2 ball containing a 1T phase, and relates to the technical field of nanometer materials, and comprises the following steps: S1, dissolving ammonium tetrathiomolybdate in a mixed solution of DMF and H2O, ultrasonic oscillation and stirring until complete dissolution, to obtain an ammonium tetrathiomolybdate solution; S2, adding hydrazine hydrate into the ammonium tetrathiomolybdate solution, and continuously stirring to obtain a reaction liquid; S3, transferring the obtained reaction liquid into a hydrothermal kettle to carry out hydrothermal reaction; S4, cooling to obtain a product after the reaction is completed, washing the product with deionized water and anhydrous ethanol in sequence, S5, vacuum drying to obtain the nano-micro-structure MoS2 ball containing the 1T phase, and the nano-micro-structure MoS2 ball is used for loading a platinum catalyst. The method has the advantages of mild conditions, simple process, green environmental protection, good repeatability, large-scale preparation of the MoS2 carrier, high catalytic activity of the obtained catalyst, excellent stability, and strong CO poisoning resistance.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, specifically to a method for preparing and applying nano-microstructured MoS2 spheres containing a 1T phase. Background Technology

[0002] Direct ethanol fuel cells (DEFCs) are considered a highly promising next-generation clean energy conversion device due to their wide availability of fuels, high energy density, and environmental friendliness. Among these, the performance of the anode catalyst is a key factor determining the overall efficiency, stability, and commercial viability of DEFCs. Platinum (Pt)-based catalysts, with their excellent C–C bond breaking ability and high initial catalytic activity, are currently recognized as the most effective catalysts for the electro-oxidation of ethanol.

[0003] In the development of platinum-based catalysts, the selection of support materials is crucial. Traditional commercial catalysts often use carbon black (such as Vulcan XC-72) to support platinum nanoparticles (Pt / C). However, Pt / C catalysts have three inherent defects in practical applications: (1) weak resistance to CO poisoning: during the oxidation of ethanol, intermediate poisoning species such as CO are easily generated, which are strongly adsorbed on the active sites of Pt, leading to rapid deactivation of the catalyst; (2) poor stability: carbon supports are prone to corrosion in electrochemical oxidation environments, which leads to the aggregation and shedding of Pt nanoparticles, resulting in catalytic performance degradation; (3) limited utilization of active sites: the disordered pore structure of conventional carbon supports affects mass transfer efficiency.

[0004] To overcome these shortcomings, researchers have attempted to develop novel support materials, such as transition metal sulfides, oxides, and carbides. Among them, molybdenum disulfide (MoS2) has attracted attention due to its unique layered structure, excellent electronic effects, and good corrosion resistance. Studies have shown that sulfur atoms on the surface of MoS2 can form strong metal-support interactions (SMSI) with Pt, modulating the electronic structure of Pt, thereby weakening the adsorption energy of CO and enhancing its resistance to poisoning. Simultaneously, the unsaturated sulfur sites at the edges of MoS2 can serve as anchoring points for Pt nanoparticles, inhibiting their migration and aggregation.

[0005] However, existing methods for preparing MoS2 supports and their morphology control still have significant shortcomings. Most of the reported MoS2 supports are nanosheets, nanoflowers, or few-layer disordered structures. These morphologies have the following problems: (1) Complex preparation process: often requires high temperature and high pressure (such as hydrothermal / solvothermal), toxic precursors (such as thioacetamide, ammonium tetrathiomolybdate) or multiple post-processing steps; (2) Unfriendly to the environment: large amounts of organic solvents or strong reducing agents are used, and waste disposal costs are high; (3) Poor reproducibility: sensitive to reaction conditions (temperature, time, pH, etc.), and large performance fluctuations between batches; (4) Difficult to prepare on a large scale: low yield at laboratory scale and insufficient morphology controllability limit its practical application. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing and applying a nano-microstructured MoS2 sphere containing a 1T phase. The process is simple, environmentally friendly, reproducible, and can be prepared on a large scale. This MoS2 support can be used to support platinum catalysts to obtain highly catalytically active catalysts.

[0007] The technical solution of the present invention: A method for preparing nano-microstructured MoS2 spheres containing a 1T phase includes the following steps: S1. Dissolve ammonium tetrathiomolybdate in a mixed solution of DMF and H2O, sonicate and stir until completely dissolved to obtain an ammonium tetrathiomolybdate solution. S2. Add hydrazine hydrate to the ammonium tetrathiomolybdate solution and continue stirring to obtain the reaction solution; S3. Transfer the obtained reaction solution into a hydrothermal reactor for hydrothermal reaction; S4. After the reaction is complete, cool to obtain the product, and wash the product successively with deionized water and anhydrous ethanol. S5. After vacuum drying, nano- and micro-structured MoS2 spheres containing 1T phase were obtained.

[0008] Preferably, the volume ratio of DMF to H2O in the mixed solution in step S1 is 3:1; The concentration of ammonium tetrathiomolybdate in the solution was 0.67 mg / mL. In step S1, the ultrasonic vibration power is 200W-300W, the frequency is 40kHz, the total duration is 15-30 minutes, and the temperature is 25℃ or below.

[0009] Preferably, the volume ratio of ammonium tetrathiomolybdate solution to hydrazine hydrate in step S2 is 100:3; The stirring time in step S2 to obtain the reaction solution is 0.5-2 hours.

[0010] Preferably, the temperature of the hydrothermal reaction in step S3 is 200-220℃, and the time of the hydrothermal reaction in step S3 is 6-10h.

[0011] Preferably, the ratio of product to deionized water in step S4 is 1 mg / 5-10 mL; In step S4, the volume ratio of deionized water to anhydrous ethanol is 1-2:1.

[0012] Preferably, the vacuum drying temperature in step S5 is 60-100℃, the vacuum drying time is 12-24h, and the vacuum degree of vacuum drying is not higher than -0.09MPa.

[0013] The application of a method for preparing nano-microstructured MoS2 spheres containing a 1T phase to prepare Pt / MoS2 working electrodes.

[0014] Preferably, the method for preparing the Pt / MoS2 working electrode is as follows: S1. Dissolve ammonium tetrathiomolybdate in a mixed solution of DMF and H2O, sonicate and stir until completely dissolved to obtain an ammonium tetrathiomolybdate solution. S2. Add hydrazine hydrate to the ammonium tetrathiomolybdate solution and continue stirring to obtain the reaction solution; S3. Transfer the obtained reaction solution and indium tin oxide glass into a hydrothermal reactor for hydrothermal reaction; S4. After the reaction is complete, cool to obtain the product, and wash the product successively with deionized water and anhydrous ethanol. S5. After vacuum drying, MoS2 / ITO with nano-micro structured MoS2 spheres containing 1T phase is obtained. S6. Using MoS2 / ITO as the working electrode, platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, Pt / MoS2 working electrode was obtained by electroplating at -0.2V for 100s in a solution containing 2.0mM H2PtCl6 and 0.1M H2SO4.

[0015] Preferably, a three-electrode system is used for electrochemical testing: counter electrode: Pt wire, reference electrode: saturated calomel electrode, working electrode: Pt / MoS2. 2。

[0016] Preferably, the solution used for electrochemical testing is a 0.1M H2SO4 solution saturated with N2, a 0.1M H2SO4 + 0.1M C2H5OH solution, or a 0.1M H2SO4 solution.

[0017] The beneficial effects of this invention are: The method of this invention is mild, simple, environmentally friendly, and highly reproducible. It can be used to prepare MoS2 support on a large scale and then used to support platinum catalysts to obtain high catalytic activity, excellent stability and strong resistance to CO poisoning. This is of great value for promoting the practical application of direct ethanol fuel cells. Attached Figure Description

[0018] Figure 1 The X-ray diffraction (XRD) pattern of MoS2 spheres.

[0019] Figure 2 This is a scanning electron microscope (SEM) image of a MoS2 sphere.

[0020] Figure 3 This is the X-ray photoelectron spectroscopy (XPS) spectrum of Mo 3d.

[0021] Figure 4 This is the X-ray photoelectron spectroscopy (XPS) spectrum of S 2p.

[0022] Figure 5 Cyclic voltammetry (CV) curves of Pt / C and Pt / MoS2 in 0.1 M H2SO4.

[0023] Figure 6 The CV curves of the two catalysts in 0.1M H2SO4 + 0.1M C2H5OH are shown.

[0024] Figure 7 The current-time (it) curves of Pt / C and Pt / MoS2 in the same alkyd mixture are shown.

[0025] Figure 8 The image shows the results of the CO leaching experiment. Detailed Implementation Example 1

[0026] A method for preparing nano-microstructured MoS2 spheres containing a 1T phase includes the following steps: 20 mg of ammonium tetrathiomolybdate is dissolved in 30 mL of a mixed solution of DMF and H2O with a volume ratio of 3:1. The solution is ultrasonically vibrated and stirred until completely dissolved. The ultrasonic vibration power is 250 W, the frequency is 40 kHz, the total duration is 20 minutes, and the temperature is 20 °C. Subsequently, 90 µL of hydrazine hydrate is added, and stirring is continued for 1 hour. The resulting solution and clean indium tin oxide (ITO) glass are transferred to a hydrothermal reactor and reacted at 210 °C for 8 hours. After the reaction is completed, the product is cooled to obtain the product. The product is washed successively with 35 mL of deionized water and 25 mL of anhydrous ethanol. The product is vacuum dried at 60 °C for 24 hours, and the vacuum degree of the vacuum drying is not higher than -0.09 MPa. After vacuum drying, nano-microstructured MoS2 / ITO containing a 1T phase is obtained. Using MoS2 / ITO as the working electrode, platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, electroplating was performed at -0.2V for 100s in a solution containing 2.0mM H2PtCl6 and 0.1M H2SO4.

[0027] Comparative Example 1 Preparation of a commercial Pt / C working electrode: 1 mg Pt / C was dispersed in a mixture of 0.1 mL deionized water and 0.9 mL isopropanol and sonicated for 30 min; 20 µL Nafion (5 wt%) was added and sonicated for another 30 min to obtain a catalyst suspension. 10 µL of the suspension was drop-coated onto the surface of an ITO electrode and dried at room temperature (20 °C) for 0.2 h.

[0028] Electrochemical testing Electrochemical tests were performed using a three-electrode system (counter electrode: Pt wire, reference electrode: saturated calomel electrode, working electrode: Pt / MoS2 or commercial Pt / C (comparative example)). CV curves (-0.32–0.80 V, 50 mV·s) were measured in a N2-saturated 0.1 M H2SO4 solution. -1 The electrochemical active area was calculated. The CV (coefficient of performance) was measured in a 0.1 M H₂SO₄ + 0.1 M C₂H₅OH solution (-0.20–1.15 V, 50 mV·s⁻¹). -1 The catalytic activity and stability were evaluated using CA (0.6V). Finally, the CO toxicity CV curves (-0.25–0.80V, 50 mV·s) were tested in 0.1 M H₂SO₄ solution. -1 ).

[0029] The experimental results are as follows: Figure 1 The image shows the X-ray diffraction (XRD) pattern of MoS2 spheres. Figure 1 As shown, the characteristic diffraction peaks of MoS2 appear at 2θ = 13.8°, 33.2°, 39.4° and 58.8°, corresponding to the (002), (100), (103) and (110) crystal planes, respectively (JCPDS, PDF#37-1492).

[0030] Figure 2 This is a scanning electron microscope (SEM) image of MoS2 spheres. The SEM image shows that MoS2 exhibits a spherical morphology, with particle diameters ranging from 0.5 to 1.5 μm.

[0031] Figure 3 and Figure 4 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of MoS2 spheres. Figure 3 The image shows the XPS spectrum of Mo 3d, where the two main peaks at 228.78 and 231.98 eV correspond to Mo 3d and 231.98 eV, respectively. 4+ 3D 5 / 2 and Mo 4+ 3D 3 / 2 The weaker peak at 226.17 eV was assigned to S 2s. Fitting the Mo3d spectrum yielded five peaks at 226.17, 228.68, 229.25, 231.92, and 232.72 eV, which were assigned to S2s and 1T phase Mo3d, respectively. 5 / 2 2H phase Mo3d 5 / 2 1T phase Mo3d 3 / 2 Mo3d with 2H phase 3 / 2 This indicates that both the 1T and 2H phases exist in MoS2, with a higher content of the 1T phase. Since the 1T phase has higher conductivity, it enhances the conductivity of MoS2 and the catalytic activity of Pt / MoS2 for ethanol when used as a support material. Figure 4 The XPS spectrum of S 2p yields five peaks, located at 161.53, 162.25, 162.98, 163.70, and 169.11 eV, corresponding to S 2- 2p 3 / 2 S 2- 2p 1 / 2 Bridge connecting S2 2- 2p 3 / 2 Bridge connecting S2 2- 2p 1 / 2 and S 4+ S 4+ This originates from the oxidation of S or the incomplete reduction of the sulfuric acid functional group. It has been reported that bridging S2... 2- and top position S 2- It is the active site of MoS2, and its abundant presence is beneficial for the catalytic oxidation of ethanol by Pt / MoS2.

[0032] Figure 5 The cyclic voltammetry (CV) curves of Pt / C and Pt / MoS2 in 0.1 M H2SO4 are shown. Both exhibit the typical characteristic regions and peak positions of polycrystalline Pt in this electrolyte. Compared to commercial Pt / C (Comparative Example 1), Pt / MoS2 has a larger hydrogen adsorption / desorption area and a stronger reduction peak, indicating that the latter has higher catalytic activity.

[0033] Figure 6 CV curves for the two catalysts in 0.1 M H₂SO₄ + 0.1 M C₂H₅OH are presented. During the forward scan, the current density of Pt / MoS₂ is higher than that of Pt / C, indicating superior activity in the ethanol oxidation reaction (EOR). Furthermore, both the onset potential and peak potential of Pt / MoS₂ show a negative shift compared to Pt / C, further confirming the enhanced catalytic activity.

[0034] Figure 7 The current-time (it) curves of Pt / C and Pt / MoS2 in the same alkyd mixture are shown to evaluate their stability. In the initial stage of the test, the current density of all catalysts decreased sharply, due to the poisoning effect of the CO intermediate and the completion of double-layer charging. Subsequently, the current density gradually decreased and stabilized, corresponding to the slow deactivation of the catalyst. Throughout the test, Pt / MoS2 consistently maintained a higher current density than Pt / C, indicating its superior stability.

[0035] Figure 8 The results of the CO leaching experiment are presented. Each curve includes the CO oxidation peak and the hydrogen adsorption / desorption peak. Compared with commercial Pt / C, all peak positions of Pt / MoS2 show a negative shift, indicating that this catalyst has stronger CO oxidation ability and better resistance to CO poisoning.

[0036] Example 2 A method for preparing nano-microstructured MoS2 spheres containing a 1T phase includes the following steps: 20 mg of ammonium tetrathiomolybdate is dissolved in 30 mL of a mixed solution of DMF and H2O with a volume ratio of 3:1. The solution is ultrasonically vibrated and stirred until completely dissolved. The ultrasonic vibration power is 250 W, the frequency is 40 kHz, the total duration is 20 minutes, and the temperature is 20 °C. Subsequently, 90 µL of hydrazine hydrate is added, and stirring is continued for 2 hours. The resulting solution and clean indium tin oxide (ITO) glass are transferred to a hydrothermal reactor and reacted at 220 °C for 6 hours. After the reaction is completed, the product is cooled to obtain the product. The product is washed successively with 60 mL of deionized water and 30 mL of anhydrous ethanol. The product is vacuum dried at 80 °C for 20 hours, and the vacuum degree of the vacuum drying is not higher than -0.09 MPa. After vacuum drying, nano-microstructured MoS2 / ITO containing a 1T phase is obtained. Using MoS2 / ITO as the working electrode, platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, electroplating was performed at -0.2V for 100s in a solution containing 2.0mM H2PtCl6 and 0.1M H2SO4.

[0037] Example 3 A method for preparing nano-microstructured MoS2 spheres containing a 1T phase includes the following steps: 20 mg of ammonium tetrathiomolybdate is dissolved in 30 mL of a mixed solution of DMF and H2O with a volume ratio of 3:1. The solution is ultrasonically vibrated and stirred until completely dissolved. The ultrasonic vibration power is 300 W, the frequency is 40 kHz, the total duration is 15 minutes, and the temperature is 25 °C. Subsequently, 90 µL of hydrazine hydrate is added, and stirring is continued for 0.5 hours. The resulting solution and clean indium tin oxide (ITO) glass are transferred to a hydrothermal reactor and reacted at 200 °C for 10 hours. After the reaction is completed, the product is cooled to obtain the product. The product is washed successively with 40 mL of deionized water and 25 mL of anhydrous ethanol. The product is vacuum dried at 100 °C for 12 hours, and the vacuum degree is not higher than -0.09 MPa. After vacuum drying, nano-microstructured MoS2 / ITO containing a 1T phase is obtained. Using MoS2 / ITO as the working electrode, platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, electroplating was performed at -0.2V for 100s in a solution containing 2.0mM H2PtCl6 and 0.1M H2SO4.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing nano-microstructured MoS2 spheres containing a 1T phase, characterized in that, Includes the following steps: S1. Dissolve ammonium tetrathiomolybdate in a mixed solution of DMF and H2O, sonicate and stir until completely dissolved to obtain an ammonium tetrathiomolybdate solution. S2. Add hydrazine hydrate to the ammonium tetrathiomolybdate solution and continue stirring to obtain the reaction solution; S3. Transfer the obtained reaction solution into a hydrothermal reactor for hydrothermal reaction; S4. After the reaction is complete, cool to obtain the product, and wash the product successively with deionized water and anhydrous ethanol. S5. After vacuum drying, nano- and micro-structured MoS2 spheres containing 1T phase were obtained.

2. The method for preparing nano- / micro-structured MoS2 spheres containing a 1T phase according to claim 1, characterized in that, In step S1, the volume ratio of DMF to H2O in the mixed solution is 3:1; The concentration of ammonium tetrathiomolybdate in the solution was 0.67 mg / mL. In step S1, the ultrasonic oscillation power is 200W-300W, the frequency is 40kHz, the total duration is 15-30 minutes, and the temperature is 25℃ or below.

3. The method for preparing nano- / micro-structured MoS2 spheres containing a 1T phase according to claim 1, characterized in that, In step S2, the volume ratio of ammonium tetrathiomolybdate solution to hydrazine hydrate is 100:

3. The stirring time in step S2 to obtain the reaction solution is 0.5-2 hours.

4. The method for preparing nano- / micro-structured MoS2 spheres containing a 1T phase according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step S3 is 200-220℃, and the time of the hydrothermal reaction in step S3 is 6-10h.

5. The method for preparing nano- / micro-structured MoS2 spheres containing a 1T phase according to claim 1, characterized in that, In step S4, the ratio of product to deionized water is 1 mg / 5-10 mL; In step S4, the volume ratio of deionized water to anhydrous ethanol is 1-2:

1.

6. The method for preparing nano- / micro-structured MoS2 spheres containing a 1T phase according to claim 1, characterized in that, In step S5, the vacuum drying temperature is 60-100℃, the vacuum drying time is 12-24h, and the vacuum degree of vacuum drying is not higher than -0.09MPa.

7. The application of a nano-microstructured MoS2 sphere prepared by the method for preparing a 1T phase-containing nano-microstructured MoS2 sphere as described in any one of claims 1-6, characterized in that, Used to prepare Pt / MoS2 working electrodes.

8. The application according to claim 7, characterized in that, The method for preparing the Pt / MoS2 working electrode is as follows: S1. Dissolve ammonium tetrathiomolybdate in a mixed solution of DMF and H2O, sonicate and stir until completely dissolved to obtain an ammonium tetrathiomolybdate solution. S2. Add hydrazine hydrate to the ammonium tetrathiomolybdate solution and continue stirring to obtain the reaction solution; S3. Transfer the obtained reaction solution and indium tin oxide glass into a hydrothermal reactor for hydrothermal reaction; S4. After the reaction is complete, cool to obtain the product, and wash the product successively with deionized water and anhydrous ethanol. S5. After vacuum drying, MoS2 / ITO containing 1T phase nano-micro structured MoS2 spheres was obtained. S6. Using MoS2 / ITO as the working electrode, platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, Pt / MoS2 working electrode was obtained by electroplating at -0.2V for 100s in a solution containing 2.0mM H2PtCl6 and 0.1M H2SO4.

9. The application according to claim 8, characterized in that, Electrochemical tests were performed using a three-electrode system: counter electrode: Pt wire; reference electrode: saturated calomel electrode; working electrode: Pt / MoS₂. 2。 10. The application according to claim 8, characterized in that, The solutions used for electrochemical testing are 0.1M H2SO4 solution saturated with N2, 0.1M H2SO4 + 0.1M C2H5OH solution, or 0.1M H2SO4 solution.

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