A method for preparing a copper-supported molybdenum sulfide Cu-MoS2 catalyst and its application
By loading copper atoms onto the surface of MoS2 to prepare Cu-MoS2 catalyst, the problem of instability of the metal 1T-MoS2 phase was solved, the number of catalytic active sites was increased, and the activity of ammonia synthesis was significantly improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG HUAYUAN PIGMENT CO LTD
- Filing Date
- 2023-10-31
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies struggle to stably maintain the metallic 1T-MoS2 phase, causing it to rapidly transform into the thermodynamically stable 2H phase at room temperature, thus affecting catalytic performance.
A Cu-MoS2 catalyst was prepared by loading copper atoms onto the surface of MoS2. The copper atoms stabilized the 1T phase, and the number of active sites was increased by photocatalysis.
The conversion rate of ammonia synthesis was significantly improved, and the copper-supported molybdenum sulfide catalyst increased the activity of ammonia synthesis by nearly 4 times.
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Figure CN117654556B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalysis technology for ammonia synthesis, specifically to a method for preparing a copper-supported molybdenum sulfide (Cu-MoS2) catalyst and its application. Background Technology
[0002] Transition metal dichalcogenides (TMDs), with their layered structure, are among the 2D materials with a wide range of applications. Because the dissociation energy of the metal-sulfur bond is much higher than that of the metallic bond, single atoms can be easily anchored at the edges or substrate S sites of supported TMDs. MoS2 is considered one of the most promising candidates for incorporating single atoms to enhance catalytic performance. MoS2 is known to exhibit several polymorphs, primarily including the octahedral prism-coordinated 1T phase (or disordered 1T' and 1T”) and the trigonal prism-coordinated 2H phase. Compared to the semiconductor 2H-MoS2, the metallic 1T phase is a more suitable catalyst due to its abundant active sites and excellent conductivity; however, the high-energy configuration of 1T-MoS2 leads to thermodynamic instability and a rapid transformation to the 2H phase at room temperature.
[0003] It has been reported that metal atoms embedded in the interlayer, such as Li, Na, and K, can stabilize the 1T phase of MoS2. Furthermore, spatial confinement has been shown to effectively enhance this effect. Based on the above, this application prepares a copper-supported molybdenum sulfide photocatalyst and uses it as a photocatalyst for ammonia synthesis. Summary of the Invention
[0004] The present invention aims to provide a method for preparing a copper-supported molybdenum sulfide (Cu-MoS2) catalyst and its application.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0006] A method for preparing a copper-supported molybdenum sulfide (Cu-MoS2) catalyst and its application, characterized by comprising the following steps:
[0007] Step (1): Preparation of molybdenum sulfide
[0008] Dissolve Na2MoO4·2H2O and thiourea in water, sonicate for 5-10 min, stir for 30-40 min to obtain a homogeneous solution, then transfer the solution to a high-pressure reactor in a polytetrafluoroethylene container, heat to 180-200℃, maintain under autogenous pressure for 24-36 hours, cool to room temperature, collect the product by centrifugation, wash with water 3 times and ethanol 2 times, and finally vacuum dry at 50-70℃ to obtain the MoS2 catalyst.
[0009] Step (2): Preparation of Cu-MoS2 catalyst
[0010] The MoS2 catalyst obtained in step (1) is dispersed in a methanol aqueous solution, CuCl2 aqueous solution is added, and the mixture is stirred for 30-50 min. Then, it is placed under a 300-500W full-spectrum light lamp for 1-3 h. After washing with water 3 times and ethanol 2 times, the Cu-MoS2 catalyst is obtained by vacuum drying at 50-60℃.
[0011] Furthermore, in step (1), the molar ratio of Na2MoO4·2H2O to thiourea is 1:2.8 to 4.8.
[0012] Furthermore, the concentration of the methanol aqueous solution in step (2) is 5% to 10%.
[0013] Furthermore, in step (2), the concentration of the CuCl2 aqueous solution is 0.01 g / mL.
[0014] Furthermore, in step (2), MoS2 is 1% of the mass of CuCl2.
[0015] This invention provides a copper-supported molybdenum sulfide Cu-MoS2 catalyst prepared by the aforementioned method.
[0016] This invention also provides the application of the copper-supported molybdenum sulfide Cu-MoS2 catalyst in the photocatalysis of ammonia synthesis. 10-100 mg of Cu-MoS2 catalyst is ultrasonically dispersed in water. The reaction solution is placed in a double-layer reaction tube, high-purity N2 is introduced and stirred for 30-60 min for dark treatment to remove dissolved O2 in the water and achieve adsorption-desorption equilibrium between the catalyst and N2. N2 is continuously introduced and the reaction solution is placed under xenon lamp irradiation and continuously stirred to synthesize ammonia.
[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows:
[0018] The method for preparing the copper-supported molybdenum sulfide (Cu-MoS2) catalyst for ammonia synthesis provided by this invention is simple and can yield Cu-MoS2 catalysts with good crystal structure. Compared with pure molybdenum sulfide catalysts, the constructed copper-supported molybdenum sulfide catalyst increases the number of active sites, thereby improving the conversion rate of ammonia synthesis by nearly 4 times. Attached Figure Description
[0019] Figure 1 The image shows the XRD pattern of Cu-MoS2 in Example 1.
[0020] Figure 2 This is a SEM image of MoS2 in Example 1.
[0021] Figure 3 This is a SEM image of Cu-MoS2 in Example 1.
[0022] Figure 4 NH4 + The standard curve graph.
[0023] Figure 5 The images show the photocatalytic ammonia synthesis activity of Example 1 and Comparative Example 1. Detailed Implementation
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention. Specific techniques or conditions not specified in the embodiments are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified can be obtained commercially through conventional products.
[0025] Example 1
[0026] Step (1): Preparation of molybdenum sulfide
[0027] 5 mmol Na₂MoO₄·2H₂O and 24 mmol thiourea were dissolved in 50 mL of water, sonicated for 10 min, and stirred for 30 min to obtain a homogeneous solution. The solution was then transferred to a 100 mL high-pressure autoclave, heated to 200 °C, and maintained under autogenous pressure for 24 hours. After cooling to room temperature, the product was collected by centrifugation, washed three times with water and twice with ethanol, and finally vacuum dried at 50 °C to obtain the MoS₂ catalyst. The SEM image of the MoS₂ catalyst is shown below. Figure 2 As shown;
[0028] Step (2) Preparation of Cu-MoS2 catalyst
[0029] The MoS2 catalyst obtained in step (1) was dispersed in 50 mL of 10% methanol aqueous solution, and 1 mL of CuCl2 aqueous solution with a concentration of 0.01 g / mL was added. The mixture was stirred for 50 min, then irradiated under a 300 W full-spectrum light lamp for 1 h. After washing with water three times and ethanol twice, the mixture was finally vacuum dried at 50–60 °C for 24 h to obtain the Cu-MoS2 catalyst. The XRD and SEM images of the Cu-MoS2 catalyst are shown below. Figure 1 and Figure 3 As shown.
[0030] Comparative Example 1
[0031] The MoS2 catalyst prepared in step (1) of Example 1 was used directly.
[0032] Preparation of standard curve
[0033] Step (1): Weigh 1.0g of NH4Cl and place it in a forced-air drying oven at 105℃ for 2h;
[0034] Step (2): Prepare a 4 μg / mL ammonia standard solution using the dried NH4Cl.
[0035] Step (3): Using a 1000 μL pipette, take 0, 50, 100, 150, 200, 250, 400, 750, 1250 and 2000 μL of NH4, respectively. + The standard solution was added to 5 mL colorimetric tubes and then diluted to 2 mL.
[0036] Step (4): Finally, add 2 mL of reagent A, 1 mL of reagent B, and 0.2 mL of reagent C to the above series of solutions respectively, shake thoroughly, let stand for 2 hours, and then detect the absorbance at λ = 655 nm. Perform linear fitting to obtain NH4. + The standard curve of absorbance A versus concentration C is shown below. Figure 4 As shown.
[0037] Photocatalytic ammonia synthesis performance test
[0038] A 300W xenon lamp (200nm<λ<800nm) was used as a simulated visible light source to simulate the photocatalytic synthesis of ammonia by sunlight as a model reaction. The absorbance at 655nm was measured by a UV-Vis spectrophotometer to determine the amount of ammonia generated, thereby evaluating the photocatalytic performance of the catalyst.
[0039] 10 mg of Cu-MoS2 catalyst from Example 1 and 10 mg of MoS2 catalyst from Example 2 were ultrasonically dispersed in water for 10 min. The two reaction solutions were placed in double-layered reaction tubes, and high-purity N2 was introduced while stirring for 30 min in the dark to remove dissolved O2 and achieve adsorption-desorption equilibrium between the catalyst and N2. N2 was continuously introduced, and the two reaction solutions were then placed under 300W xenon lamp irradiation with continuous stirring for photocatalytic ammonia synthesis. After 1 h of reaction, 2 mL of solution was taken from each of the two double-layered reaction tubes, filtered through a 0.22 μm organic filter membrane, and 2 mL of reagent A, 1 mL of reagent B, and 0.2 mL of reagent C were added. "Reagent A" refers to a mixed solution of 11.56 g salicylic acid, 11.56 g sodium citrate, and 1 M NaOH; "Reagent B" refers to a 0.05 M sodium hypochlorite solution; and "Reagent C" refers to a 10 g / L sodium nitroprusside solution. The absorbance at 655 nm was measured after 2 h. Based on the standard curve, the ammonia concentration C (μmol / g / h) was converted, and the results are shown in the figure. Figure 5 As shown.
[0040] pass Figure 5 It can be seen that under 300W xenon lamp irradiation, the ammonia synthesis activity of MoS2 catalyst is only about 20.83 μmol / g / h, while the ammonia synthesis activity of Cu-MoS2 catalyst is as high as about 98.55 μmol / g / h. Cu loading on MoS2 can significantly enhance the ammonia synthesis catalytic activity.
[0041] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. Application of copper-supported molybdenum sulfide (Cu-MoS2) catalyst in photocatalytic ammonia synthesis, wherein, The copper-supported molybdenum sulfide Cu-MoS2 catalyst was prepared by the following steps: Step (1): Preparation of molybdenum sulfide Dissolve Na2MoO4·2H2O and thiourea in water, sonicate for 5-10 min, stir for 30-40 min to obtain a homogeneous solution, then transfer the solution to a high-pressure reactor lined with polytetrafluoroethylene, heat to 180-200℃, maintain under autogenous pressure for 24-36 hours, cool to room temperature, collect the product by centrifugation, wash with water 3 times and ethanol 2 times, and finally vacuum dry at 50-70℃ to obtain the MoS2 catalyst. Step (2): Preparation of Cu-MoS2 catalyst The MoS2 catalyst obtained in step (1) is dispersed in a methanol aqueous solution, CuCl2 aqueous solution is added, and the mixture is stirred for 30-50 min. Then it is placed under a 300-500W full-spectrum light lamp for 1-3 h, washed with water 3 times and ethanol 2 times respectively, and finally vacuum dried at 50-60℃ to obtain Cu-MoS2 catalyst. The application includes: ultrasonically dispersing 10-100 mg of Cu-MoS2 catalyst in water, placing the reaction solution in a double-layer reaction tube, introducing high-purity N2 and stirring for 30-60 min for dark treatment to remove dissolved O2 in the water, while achieving adsorption-desorption equilibrium between the catalyst and N2, continuously introducing N2, and placing the reaction solution under xenon lamp irradiation and stirring continuously to synthesize ammonia.
2. The application according to claim 1, characterized in that, In step (1), the molar ratio of Na2MoO4·2H2O to thiourea is 1:2.8~4.
8.
3. The application according to claim 1, characterized in that, The concentration of the methanol aqueous solution in step (2) is 5%~10%.
4. The application according to claim 1, characterized in that, In step (2), the concentration of CuCl2 aqueous solution is 0.01 g / mL.
5. The application according to claim 1, characterized in that, In step (2), MoS2 is 1% of the mass of CuCl2.