Preparation method and application of enzyme mimetic catalyst

Abstract

The invention discloses a tungsten nitride mimic enzyme catalyst and a preparation method thereof. According to the catalyst, a tungsten precursor is nitrided through a high-temperature heating method in an ammonia gas atmosphere, and tungsten nitride is prepared. Tungsten nitride has peroxidase activity and can be used for antibacterial materials, antibacterial preparations and the like. The preparation method provided by the invention is simple and convenient, the preparation time is short, and the prepared material has enzyme-like catalytic activity, can detect low-concentration hydrogen peroxide, and has good bactericidal performance.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials, and in particular to a tungsten nitride enzyme-mimicking catalytic material and a preparation method and application thereof. Background Art

[0002] Tungsten nitride is a new type of catalytic material, and its surface properties and catalytic performance are similar to those of precious metals. The application of tungsten nitride catalysts can avoid sulfur pollution caused by industrial catalysts, so it has a wide range of application prospects as a catalyst. Due to the peroxidase-like activity of tungsten nitride, hydrogen peroxide can be catalyzed into hydroxyl free radicals with oxidizing ability, so it has application prospects in the biomedical field.

[0003] Studies have shown that the introduction of nitrogen atoms is the source of the enzymatic activity of tungsten nitride. At the same time, through the preparation method provided in this article, the morphology of tungsten sulfide is not changed, and the final tungsten nitride does not show obvious aggregation, which reduces the reduction of surface area caused by sintering and maintains good dispersibility. In addition, the preparation method is simple and low in cost, which is conducive to subsequent biological application research and application. Summary of the invention

[0004] The purpose of the present invention is to provide a novel method for preparing a tungsten nitride bactericidal material with pseudo-enzyme activity.

[0005] The bactericidal material of the present invention is characterized in that the catalyst is prepared by in-situ nitridation of tungsten sulfide nanospheres to prepare tungsten nitride, wherein the diameter of the tungsten nitride nanospheres is 0.5-2 μm.

[0006] The above-mentioned tungsten nitride nanosphere catalyst is prepared by the following method: (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0007] (2) Transfer the above precursor solution to a reaction vessel and react at 220±10°C for 24±2 hours.

[0008] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80±10°C for 12±2 hours.

[0009] (4) The powder dried in step (3) was added to a quartz boat and maintained at 800°C for 4 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, vertical sheet-structured tungsten nitride hollow nanospheres with enzyme-like catalytic activity were obtained.

[0010] The tungsten nitride nanospheres involved in the invention have peroxidase activity.

[0011] The tungsten nitride nanospheres provided by the present invention have added antibacterial properties on the basis of maintaining the structural characteristics of the tungsten sulfide raw material, have excellent bacterial killing effects, have application prospects for antibacterial materials and antibacterial preparations, and expand the types and applications of antibacterial materials and antibacterial preparations. The preparation method provided by the present invention is simple to operate and has a short synthesis time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a scanning electron microscope (SEM) image of the tungsten sulfide nanospheres prepared in Example 1 of the present invention.

[0013] Figure 2 This is a scanning electron microscope (SEM) image of the tungsten nitride nanospheres prepared in Example 1 of the present invention.

[0014] Figure 3 This is a test of the catalase activity of the tungsten nitride nanospheres prepared in Example 1 of the present invention.

[0015] Figure 4 This is a table showing the bactericidal effects of the tungsten nitride nanospheres prepared in Example 1 of the present invention, the tungsten nitride nanospheres prepared in Example 2, the tungsten nitride nanospheres prepared in Example 3, the tungsten nitride nanospheres prepared in Example 4, the tungsten nitride nanospheres prepared in Example 5, the tungsten nitride nanospheres prepared in Comparative Example 1, and the tungsten nitride nanospheres prepared in Comparative Example 2. DETAILED DESCRIPTION

[0016] The present invention is further described in detail and completely below in conjunction with the embodiments, but the contents of the present invention are not limited thereto.

[0017] Example 1 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0018] (2) The precursor solution was transferred to a reactor and reacted at 220°C for 24 hours.

[0019] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0020] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. In a tube furnace, heat the mixture at 800°C for 1 hour with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0021] Example 2 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0022] (2) The precursor solution was transferred to a reactor and reacted at 220°C for 24 hours.

[0023] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0024] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 800°C for 4 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0025] Example 3 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0026] (2) The precursor solution was transferred to a reactor and reacted at 220°C for 24 hours.

[0027] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0028] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 800 °C for 7 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5 °C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0029] Example 4 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0030] (2) The precursor solution was transferred to a reactor and reacted at 220°C for 24 hours.

[0031] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0032] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 500°C for 4 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0033] Example 5 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0034] (2) The precursor solution was transferred to a reaction vessel and reacted at 120°C for 24 hours.

[0035] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0036] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 800°C for 4 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0037] Comparative Example 1 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0038] (2) The precursor solution was transferred to a reactor and reacted at 80°C for 24 hours.

[0039] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0040] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 800 °C for 1 hour in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5 °C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0041] Comparative Example 2 (1) Dissolve 1.18 g of tungsten chloride and 1.12 g of thioacetamide in 50 mL of ultrapure water and stir at room temperature for 60 min to obtain a tungsten sulfide precursor solution.

[0042] (2) The precursor solution was transferred to a reactor and reacted at 220 °C for 24 hours.

[0043] (3) Filter the solution after the reaction in step (2), wash the generated precipitate with deionized water and ethanol for 3 to 5 times respectively, and then dry the separated precipitate at 80° C. for 12 hours.

[0044] (4) Weigh 0.5 g of the powder dried in step (3) and add it to a quartz boat. Keep the temperature at 200°C for 2 hours in a tube furnace with an ammonia flow rate of 80 mL / min, an argon flow rate of 20 mL / min, and a heating rate of 5°C / min. After natural cooling, tungsten nitride nanospheres with enzyme-like catalytic activity are obtained.

[0045] Test Example 1 Scanning electron microscope (SEM) observations.

[0046] like Figure 1 Shown is the scanning electron microscope (SEM) image of tungsten sulfide nanospheres.

[0047] Test Example 2 Scanning electron microscope (SEM) observations.

[0048] like Figure 2 Shown is the scanning electron microscope (SEM) image of tungsten nitride nanospheres.

[0049] Test Example 3 Test of peroxidase activity of hollow tungsten nitride nanospheres with sheet structure. Add 20 µg of material, 800 µM 3,3',5,5'-tetramethylbenzidine, and different amounts of hydrogen peroxide to sodium acetate buffer with pH 3.6. After shaking well, quickly place it under a UV-visible spectrophotometer to detect its absorbance in the wavelength range of 300-800 nm. The pseudoenzyme activity can be understood based on the absorbance. Figure 3 As shown, it can be seen that with the increase of hydrogen peroxide concentration, its enzyme activity gradually increases, and the reaction rate also increases with the increase of concentration.

[0050] Test Example 4 Antibacterial effect of hollow tungsten nitride nanospheres with sheet structure.

[0051] The antibacterial effect was determined by the plate count method. The shaken E. coli solution was placed in a test tube, centrifuged (6000rpm, 2min), the supernatant was discarded, and the solution was washed three times with 10mL of PBS, centrifuged (6000rpm, 2min), and the supernatant was discarded. 10mL of PBS was added to the test tube to redisperse the bacteria. 200μL of the redispersed bacterial solution was placed in a 96-well plate and the absorbance was measured at 600nm on an ELISA reader (the absorbance of E. coli is 0.15). The bacterial solution was gradiently diluted 10 4 After the bacterial solution was multiplied by 1:1, 400 μL of the bacterial solution was incubated with 200 μg / mL of the test material (prepared in the embodiment and the comparative example) for 30 min, and then 100 μL was taken for plating, and the mixture was incubated in an incubator at 37 degrees for 18 hours, and then counted. Figure 4 The statistical results of the plate counting method. By comparing different materials, it can be seen that the antibacterial effect of the tungsten nitride hollow nanospheres with sheet structure prepared by 4 hours of nitridation is the most obvious.

[0052] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

Claims

1. An enzyme-mimicking catalyst, characterized in that: The catalyst is a tungsten nitride nanostructure.

2. The enzyme-mimicking catalyst according to claim 1, wherein the tungsten nitride nanostructure can be a nanosphere, a nanoflower, a nanosheet, a nanodot, etc.

3. The catalyst as claimed in claim 1, wherein the source of the enzyme-like catalytic activity is the coordination of N and W.

4. A method for preparing a tungsten nitride enzyme-mimicking catalyst, characterized in that: The preparation method comprises: (1) A raw material mixture of a tungsten source and a sulfur source is prepared to obtain a tungsten sulfide precursor solution.

5. (2) Transfer the above precursor solution to an autoclave and react at 220±20°C for 24±5 hours.

6. (3) The tungsten sulfide powder dried in step (2) is kept at 800±100°C for 4±3 hours in a sealed and heated ammonia atmosphere to obtain tungsten nitride nanospheres with enzyme-like catalytic activity.

7. The preparation method according to claim 4, characterized in that: The (1) includes: The tungsten source is selected from one of tungsten chloride, ammonium tetrathiotungstate or sodium tungstate; The sulfur source is selected from one of sodium thiosulfate, thiourea, ammonium sulfide or thioacetamide.

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