Niw alloy catalyst with lattice strain and preparation method and application thereof

Abstract

The application discloses a NiW alloy catalyst with lattice strain and a preparation method and application thereof, relates to the technical field of catalytic synthesis, and comprises the following steps: adding a tungsten precursor and a nickel precursor into an ethanol solution, performing ultrasonic treatment, then performing a hydrothermal reaction, cooling to room temperature, and preparing an intermediate; washing, drying, then reducing by using H2, and preparing the NiW alloy catalyst with lattice strain. When the hydrogenation catalyst provided by the application is used to catalyze a phenylacetylene hydrogenation reaction, the conversion rate of the reactant phenylacetylene is as high as 99%, and the selectivity of the product styrene is as high as 99%. The application solves the problems of low conversion rate and poor selectivity in the phenylacetylene hydrogenation conversion in the prior art.

Description

Technical Field

[0001] This invention relates to the field of catalytic synthesis technology, specifically to a NiW alloy catalyst with lattice strain, its preparation method, and its application. Background Technology

[0002] Phenylacetylene is an important component in fine chemicals, polymer materials, and pharmaceuticals. Its selective hydrogenation is a core technology for preparing high-purity styrene and synthesizing high-end polymers and pharmaceutical intermediates, mainly used for the purification of styrene monomers. Trace amounts of phenylacetylene impurities in industrial raw materials can poison polymerization catalysts and degrade material quality. Therefore, precise hydrogenation to remove impurities is a crucial step in ensuring the quality of polymer-grade styrene. Traditional purification processes mainly rely on distillation and solvent extraction, which suffer from drawbacks such as high energy consumption, low separation accuracy, significant material loss, and substantial pollution emissions. Currently, the industry primarily promotes the selective semi-hydrogenation process of phenylacetylene to styrene, which is suitable for continuous production and has outstanding environmental benefits. However, this catalytic reaction still faces significant technical challenges. Phenylacetylene contains highly reactive -C≡C triple bonds, and the hydrogenation reaction can stepwise produce styrene and ethylbenzene. Thermodynamically, the -C=C double bonds in styrene are more readily hydrogenated, easily triggering excessive hydrogenation side reactions, making it difficult for the reaction to remain in the semi-hydrogenation stage, and significantly reducing the selectivity and yield of styrene. In addition, traditional catalytic systems often add acidic or halogenated additives, which not only passivate the catalyst activity and shorten its service life, but also increase the difficulty of product separation and production costs, resulting in significant environmental governance pressure.

[0003] Currently, phenylacetylene hydrogenation catalysts are mainly classified into two categories: noble metal and non-noble metal. Noble metal catalysts such as palladium and platinum exhibit high hydrogenation activity and fast conversion rates, but they are costly, resource-scarce, and prone to inducing over-hydrogenation, making it difficult to balance activity and selectivity, thus limiting large-scale industrial application. Non-noble metal catalysts such as nickel and copper are inexpensive and widely applicable, but suffer from weaker catalytic activity, lower conversion rates, and significant selectivity degradation at high conversion rates. Existing research indicates that by employing metal-support interactions, bimetallic synergy, and surface electron and morphology modulation, the catalytic interface can be effectively optimized, side reactions suppressed, and the selectivity and stability of the catalytic system significantly improved. Green and precise catalysis is currently a research hotspot in the chemical industry. Novel catalytic materials such as single-atom catalysts, carbon-based composite materials, molecular sieves, and MOFs, with their unique structural and electronic modulation advantages, can effectively optimize hydrogenation reaction pathways, improve atom utilization, and enhance catalytic stability, showing great potential in the field of precise phenylacetylene hydrogenation. Therefore, developing novel catalytic systems that are highly active, selective, low-cost, and environmentally friendly to achieve controllable semi-hydrogenation conversion of phenylacetylene and overcome the shortcomings of traditional processes has become a key research direction in the fields of fine catalysis and polymer chemistry. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a NiW alloy catalyst with lattice strain, its preparation method, and its application, thereby resolving the issues of low conversion rate and poor selectivity in the hydrogenation conversion of phenylacetylene in the prior art.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing a NiW alloy catalyst with lattice strain is provided, comprising the following steps: (1) Add tungsten precursor and nickel precursor to ethanol solution, sonicate, then hydrothermally react, cool to room temperature to obtain intermediate; (2) The intermediate obtained in step (1) is washed, dried, and then reduced with H2 to obtain a NiW alloy catalyst with lattice strain.

[0006] The beneficial effects of this invention are as follows: Through the atomic substitution process of Ni and W atoms during hydrothermal treatment, a NiW alloy with lattice strain is obtained. Following high-temperature hydrogen reduction, a NiW alloy catalyst with lattice strain supported on a WO2 support is prepared, with NiW species dispersed in alloy form on the surface of the WO2 support. The strong interaction between the NiW alloy and the WO2 support leads to electron enrichment at the interface, effectively suppressing the over-hydrogenation of styrene. Under light irradiation, the strong LSPR effect of Ni effectively activates atmospheric pressure hydrogen, achieving highly selective hydrogenation of phenylacetylene. Under photoreaction conditions, the catalytic hydrogenation of phenylacetylene selectively generates styrene products, exhibiting high reactant conversion and good product selectivity.

[0007] Based on the above technical solution, the present invention can be further improved as follows: Furthermore, in step (1), the tungsten precursor is WCl6, and the nickel precursor is Ni(NO3)2. 3)2 ·6H2O.

[0008] Furthermore, WCl6 and Ni(NO) 3)2 The mass ratio of ·6H2O is 0.79:0.58.

[0009] Furthermore, in step (1), the hydrothermal reaction is carried out at 160°C for 12 hours.

[0010] Furthermore, in step (1), the rotation speed during the hydrothermal reaction is 20 revolutions per minute.

[0011] Furthermore, in step (2), water and ethanol are used for washing in sequence.

[0012] Furthermore, in step (2), the product is dried at 80°C for 12 hours.

[0013] Furthermore, in step (2), H2 is reduced at 450℃ for 4 hours. Furthermore, in step (2), centrifugal washing is performed at a speed of 4000 rpm.

[0014] The present invention also provides a NiW alloy catalyst with lattice strain prepared by the above method.

[0015] The present invention also provides the application of the above-mentioned NiW alloy catalyst with lattice strain in the catalytic hydrogenation reaction of phenylacetylene to prepare styrene. Furthermore, the preparation of styrene by catalytic hydrogenation of phenylacetylene includes the following steps: under a hydrogen atmosphere, phenylacetylene, isopropanol and the above-mentioned NiW alloy catalyst with lattice strain are mixed and hydrogenated under light irradiation to obtain styrene.

[0016] Furthermore, the ratio of phenylacetylene, isopropanol, and the aforementioned NiW alloy catalyst with lattice strain is 0.1-2 mmol: 1-5 mL: 20-60 mg.

[0017] Furthermore, the ratio of phenylacetylene, isopropanol, and the aforementioned NiW alloy catalyst with lattice strain is 0.1 mmol: 2 mL: 20 mg.

[0018] Furthermore, hydrogenation was carried out at 60°C for 6 hours.

[0019] Furthermore, stirring is maintained during the hydrogenation reaction.

[0020] Furthermore, the illumination conditions were a wavelength of 420-800 nm and a light intensity of 300 mW / cm². 2 .

[0021] The present invention has the following beneficial effects: 1. The catalyst system prepared by this invention does not contain precious metals, and the reaction conditions are mild and the operation is safe. The pressure is atmospheric pressure, the catalytic temperature is 60 ℃, and under neutral conditions, no acid, alkali, salt, or other co-catalysts are required.

[0022] 2. This invention prepares a NiW alloy catalyst with lattice strain supported on WO2. The strong interaction between the NiW alloy and the WO2 support leads to the enrichment of electrons at the interface, which can effectively suppress the over-hydrogenation of styrene. Under light irradiation, the strong LSPR effect of Ni can effectively activate hydrogen gas at atmospheric pressure, thus achieving highly selective hydrogenation of phenylacetylene.

[0023] 3. Experimental results show that when the hydrogenation catalyst provided by this invention is used to catalyze the hydrogenation reaction of phenylacetylene, the conversion rate of the reactant phenylacetylene is as high as 99%, and the selectivity of the product styrene is as high as 99%.

[0024] 4. After the hydrogenation reaction is completed, the system is subjected to solid-liquid separation. The separated solid material is washed and dried to recover the hydrogenation catalyst. The separated liquid material contains the target product styrene, which can be post-processed according to methods well known in the art. The hydrogenation catalyst provided by this invention has good stability and can be reused multiple times. Attached Figure Description

[0025] Figure 1 The image shows the XRD pattern of 160-NiW / WO2 prepared in Example 1.

[0026] Figure 2 TEM images of 160-NiW / WO2 from Example 1 and Ni / WO2 from Comparative Example 6.

[0027] Figure 3 XPS image of the 160-NiW / WO2 catalyst prepared in Example 1.

[0028] Figure 4 This is a theoretical simulation of the hydrogenation and desorption process of styrene molecules on the surface of a 160-NiW / WO2 catalyst. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] WCl6, purity 99.0%, purchased from Aladdin Reagents website.

[0031] Ni(NO 3)2 •6H2O, analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0032] Ethanol, analytical grade, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0033] During the catalyst performance testing, the light source instrument used was a PLS-SXE300+ with a wavelength of 420-800nm ​​and a light intensity of 300 mW / cm². 2 .

[0034] Example 1: A NiW alloy catalyst with lattice strain is prepared by the following steps: (1) Tungsten precursor (0.79g WCl6) and nickel precursor (0.58g Ni(NO)) 3)2Add 6H2O to an ethanol solution (40 mL water and 20 mL ethanol), place in an ultrasonic cleaner for ultrasonic treatment for 30 min, then transfer to a polytetrafluoroethylene liner and place in a homogeneous reactor. Adjust the hydrothermal temperature to 160 ℃ and treat for 12 h (set the rotation speed to 20 rpm). Cool to room temperature to obtain the intermediate. (2) The intermediate obtained in step (1) was washed by centrifugation with a large amount of water and ethanol (centrifuge speed of 4000 rpm), dried in a vacuum drying oven at 80 ℃ for 12 h, and then reduced by H2 at 450 ℃ for 4 h to obtain a NiW alloy catalyst with lattice strain (denoted as 160-NiW / WO2).

[0035] Comparative Example 1: A NiW / WO2 catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the hydrothermal temperature is 120°C, and the rest is the same as in Example 1, to obtain a NiW / WO2 catalyst for the hydrogenation of phenylacetylene (denoted as 120-NiW / WO2).

[0036] Comparative Example 2: A NiW / WO2 catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the hydrothermal temperature is 140°C, and the rest is the same as in Example 1, to prepare a NiW / WO2 catalyst for the hydrogenation of phenylacetylene (denoted as 140-NiW / WO2).

[0037] Comparative Example 3: A NiW / WO2 catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the hydrothermal temperature is 180°C, and the rest is the same as in Example 1, to obtain a NiW / WO2 catalyst for the hydrogenation of phenylacetylene (denoted as 180-NiW / WO2).

[0038] Comparative Example 4: A Ni / Al2O3 catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the tungsten precursor was replaced with 0.55g Al2O3, and the rest was the same as in Example 1, to prepare a Ni / Al2O3 catalyst for the hydrogenation of phenylacetylene (denoted as Ni / Al2O3).

[0039] Comparative Example 5: A Ni / MgO catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the tungsten precursor was replaced with 0.55g MgO, and the rest was the same as in Example 1, to prepare a Ni / MgO catalyst for the hydrogenation of phenylacetylene (denoted as Ni / MgO).

[0040] Comparative Example 6: A Ni / WO2 catalyst for the hydrogenation of phenylacetylene is prepared by the following steps: In step (1), the tungsten precursor was replaced with 0.55g WO2, and the rest was the same as in Example 1, to prepare a Ni / WO2 catalyst for the hydrogenation of phenylacetylene (denoted as Ni / WO2).

[0041] Test case I. The 160-NiW / WO2 prepared in Example 1 was subjected to XRD analysis, and the results are shown in the figure. Figure 1 .

[0042] Depend on Figure 1 It can be seen that, compared with the diffraction peaks of Ni metal in the standard PDF card, the diffraction peaks of Ni metal in the 160-NiW / WO2 catalyst show a significant shift in position, indicating that W metal in the 160-NiW / WO2 catalyst affects the coordination environment of Ni metal.

[0043] II. The 160-NiW / WO2 prepared in Example 1 and the Ni / WO2 prepared in Comparative Example 6 were subjected to TEM detection. The results are shown in [Figure 1]. Figure 2 ( Figure 2 In the image, a is a TEM image of the 160-NiW / WO2 catalyst, b is a TEM image of the Ni / WO2 catalyst, c is a HR-TEM image of the 160-NiW / WO2 catalyst, and d is a HR-TEM image of the Ni / WO2 catalyst.

[0044] Depend on Figure 2 As shown in section 'a', the interlayer spacing of the eight atomic layers of the NiW alloy in the preparation of the 160-NiW / WO2 catalyst is 1.656 nm, which is significantly different from the 1.632 nm interlayer spacing of the Ni metal in the Ni / WO2 catalyst. Furthermore, a comparison... Figure 2 In the c and d sections, it can also be observed that the lattice fringes of NiW alloy and Ni metal in 160-NiW / WO2 and Ni / WO2 catalysts have obvious dislocations, which proves that Ni in 160-NiW / WO2 catalyst has obvious lattice strain.

[0045] III. The 160-NiW / WO2 prepared in Example 1 was subjected to XPS detection, and the results are shown in [the table below]. Figure 3 ( Figure 3 In the diagram, a is the Ni 2p XPS plot, and b is the W 4f XPS plot.

[0046] Depend on Figure 3As can be seen from Figure a, compared with the Ni / WO2 catalyst, the binding energy of Ni species in the 160-NiW / WO2 catalyst is increased, indicating that Ni has lost electrons.

[0047] Depend on Figure 3 As can be seen in Figure b, compared with the Ni / WO2 catalyst, the binding energy of W species in the 160-NiW / WO2 catalyst is lower, indicating that W has gained electrons. This result suggests that electrons from Ni species on the surface of the 160-NiW / WO2 catalyst have transferred to the interface between the NiW alloy and the WO2 support.

[0048] IV. Theoretical calculations and simulations of the hydrogenation and desorption processes of styrene molecules on the surface of the 160-NiW / WO2 catalyst are shown in the figure. Figure 4 .

[0049] Depend on Figure 4 It can be seen that styrene molecules need to overcome an energy barrier of 1.66 eV to desorb from the 160-NiW / WO2 catalyst surface, while further hydrogenation requires overcoming an energy barrier of 2.38 eV. This indicates that the desorption process of styrene is more likely to occur, proving that the 160-NiW / WO2 catalyst is an excellent highly selective catalyst for the preparation of styrene from phenylacetylene.

[0050] V. Catalytic Performance Testing The catalysts prepared in Example 1 and Comparative Examples 1-6 were used as hydrogenation catalysts to test their catalytic performance in the hydrogenation of phenylacetylene. The specific method was as follows: 20 mg of hydrogenation catalyst, 0.1 mmol of phenylacetylene, and 2 mL of isopropanol were placed in a pressure-resistant glass reaction flask. Hydrogen gas was purged into the pressure-resistant glass reaction flask for 2 min to maintain the hydrogen atmosphere. The pressure-resistant glass reaction flask was then placed in a 60 ℃ oil bath with stirring, and the reaction was carried out for 6 h. The wavelength of the light source was 420-800 nm, and the light intensity was 300 mW / cm². 2 .

[0051] After the reaction is completed, the solid and liquid materials are separated by filtration. The products in the liquid material are analyzed directly using gas chromatography-mass spectrometry (GC-MS), as shown in Table 1. The solid material is then washed and dried to recover the hydrogenation catalyst.

[0052] Table 1. Comparison of catalytic performance between Example 1 and the multi-proportion 1-6 catalysts.

[0053] Test results show that the phenylacetylene hydrogenation reaction catalyzed by 160-NiW / WO2 achieves a phenylacetylene conversion rate of up to 99% and a styrene selectivity of up to 99%.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a NiW alloy catalyst with lattice strain, characterized in that, Includes the following steps: (1) Add tungsten precursor and nickel precursor to ethanol solution, sonicate, then hydrothermally react, cool to room temperature to obtain intermediate; (2) The intermediate obtained in step (1) is washed, dried, and then reduced with H2 to obtain a NiW alloy catalyst with lattice strain.

2. The method for preparing the NiW alloy catalyst with lattice strain according to claim 1, characterized in that, In step (1), the tungsten precursor is WCl6, and the nickel precursor is Ni(NO3)2. 3)2 ·6H2O.

3. The method for preparing the NiW alloy catalyst with lattice strain according to claim 2, characterized in that, WCl6 and Ni(NO 3)2 The mass ratio of ·6H2O is 0.79:0.

58.

4. The method for preparing the NiW alloy catalyst with lattice strain according to claim 1, characterized in that, In step (1), the hydrothermal reaction is carried out at 160℃ for 12 hours.

5. The method for preparing the NiW alloy catalyst with lattice strain according to claim 1, characterized in that, In step (2), the product is dried at 80°C for 12 hours.

6. The method for preparing the NiW alloy catalyst with lattice strain according to claim 1, characterized in that, In step (2), H2 is reduced at 450℃ for 4 hours.

7. A NiW alloy catalyst with lattice strain prepared by the method for preparing a NiW alloy catalyst with lattice strain according to any one of claims 1-6.

8. The application of the NiW alloy catalyst with lattice strain according to claim 7 in the catalytic hydrogenation reaction of phenylacetylene to prepare styrene.

9. The application according to claim 8, characterized in that, The preparation of styrene by catalytic hydrogenation of phenylacetylene includes the following steps: under a hydrogen atmosphere, phenylacetylene, isopropanol and the NiW alloy catalyst with lattice strain as described in claim 7 are mixed and hydrogenated under light irradiation to obtain styrene.

10. The application according to claim 9, characterized in that, The ratio of phenylacetylene, isopropanol, and the NiW alloy catalyst with lattice strain as described in claim 7 is 0.1-2 mmol: 1-5 mL: 20-60 mg.

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