Preparation method of catalyst doped with niobium pentoxide semiconductor
Through the preparation method of doped niobium pentoxide semiconductor catalyst, the application efficiency of pure phase Nb2O5 in the visible light range and the photogenerated electron hole recombination are solved, and the antibiotic pollutants in the water are efficiently degraded, which is characterized by green and environmental protection.
Patent Information
- Application Number
- CN202510359238.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-07-29
AI Technical Summary
The pure phase Nb2O5 catalyst has low application efficiency in the visible light range, photogenerated electrons and holes are easy to recombinate, and is not conducive to the degradation of pollutants in the oxidation reaction.
By the preparation method of doped niobium pentoxide semiconductor catalyst, niobium oxalate and ammonium molybdate are calcined after hydrothermal reaction to form a p-type niobium pentoxide catalyst, which improves the photoresponse range and the separation efficiency of photogenerated carriers.
It improves the photocatalytic activity of the catalyst and can effectively degrade antibiotic pollutants in water bodies under visible light, which is characterized by simple operation and green environmental protection.
Smart Images
Figure CN120381835A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a catalyst, in particular to a method for preparing a catalyst by utilizing doping to induce semiconductor type transformation of niobium pentoxide. Background Art
[0002] As a common transition metal oxide, niobium pentoxide (Nb2O5) has typical n-type semiconductor characteristics, high chemical stability and visible light response ability, and therefore shows broad prospects in the application of photocatalytic technology. At present, Nb2O5, as a semiconductor photocatalyst, is mainly used in the photocatalytic conversion of waste plastics in the visible light region, the activation of hydrocarbons, the photoreduction of carbon dioxide, and the removal of pollutants in the environment. Because its raw materials are widely present in nature and the synthesis method is simple and pollution-free, Nb2O5 meets the requirements of low cost, easy access and green environmental protection. However, in terms of the two requirements of high efficiency and wide light response range, pure phase Nb2O5 materials have not yet reached the expected level, mainly because pure Nb2O5 has many shortcomings. The main shortcomings of this material are as follows: (1) Wide band gap (E g (1) The photogenerated electrons and holes are easily recombined, resulting in a low separation efficiency of photogenerated carriers; (2) As an n-type semiconductor, its main carriers are free electrons, which is not conducive to the degradation of pollutants in the oxidation reaction. Summary of the Invention
[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a method for preparing a catalyst doped with niobium pentoxide semiconductor.
[0004] A method for preparing a catalyst doped with niobium pentoxide semiconductor, the method comprising the following steps:
[0005] S1, preparing a mixed solution by adding niobium oxalate to a polyethylene glycol solvent to obtain a primary mixed solution, adding an L-arginine solution while stirring the primary mixed solution, and ultrasonically treating the solution to obtain a mixed solution, wherein the niobium oxalate and the polyethylene glycol solvent are mixed at a ratio of 3-10 ml of polyethylene glycol solvent per 1 gram of niobium oxalate;
[0006] S2, adding ammonia water to the mixed solution, adjusting the mixed solution to alkaline until a white flocculent precipitate is formed, and then transferring the mixed solution into a reactor for hydrothermal reaction. After the reaction is completed, the mixed solution is cooled and placed in a drying oven to dry until a dry sample is obtained. The sample is dried and ground to obtain a powder, which is placed in a muffle furnace for calcination, kept warm, and then cooled to room temperature to obtain a precursor;
[0007] S3. Weigh the precursor and ammonium molybdate, add them together to hot water, stir in a water bath, and heat in an oven until dried up to obtain blue crystals. Among them, the mass ratio of the precursor to ammonium molybdate is 20 - 50:1 - 2;
[0008] S4. Grind the precipitated blue crystals into powder, place them in a crucible, cover it, and heat up under an inert gas atmosphere, then cool naturally to room temperature after heat preservation, and thus obtain the p-type niobium pentoxide catalyst.
[0009] As a further improvement, in the step S1, the L-arginine solution and the preliminary mixed solution are added according to a volume ratio of 1 - 2:9 - 15, and the concentration of the L-arginine solution is 1 mol / L.
[0010] As a further improvement, in the step S1, the preliminary mixed solution is magnetically stirred at room temperature for 15 - 25 minutes and ultrasonically treated for 15 - 25 minutes.
[0011] As a further improvement, in the step S2, the mass concentration of ammonia water is 28%.
[0012] As a further improvement, in the step S2, hydrothermal reaction is carried out at 150 - 200 °C in a reaction kettle for 10 - 15 hours, the temperature of the drying oven is kept at 85 - 90 °C, and it is calcined in a muffle furnace at a heating rate of 3 - 5 °C per minute to 480 °C - 500 °C, and then naturally cooled to room temperature after heat preservation for 4 - 6 hours.
[0013] As a further improvement, in the step S3, the temperature of the hot water is kept between 80 °C - 95 °C, stirred in a water bath for 2 - 3 hours, and heated in an oven at 80 - 90 °C for 20 - 30 hours.
[0014] As a further improvement, the inert gas atmosphere is a nitrogen atmosphere, the nitrogen gas flow rate is 30 mL / min, heated to 500 °C - 550 °C at a heating rate of 5 °C - 6 °C per minute, and then naturally cooled to room temperature after heat preservation for 4 - 6 hours.
[0015] As a further improvement, in the step S2, the pH of the mixed solution is adjusted to 7.5 - 8.5.
[0016] Compared with the prior art, the present invention has the following beneficial technical effects:
[0017] The main raw material is niobium oxalate, and the main reagent for preparing this catalyst is ammonium molybdate. The precursor of the product is obtained after the niobium oxalate undergoes hydrothermal reaction, and the final sample is obtained by calcining the precursor and ammonium molybdate. It has the characteristics of few types of raw materials, simple operation method, simple process, green environmental protection, etc. The obtained p-type niobium pentoxide has high photocatalytic activity and strong oxidizing property, and can be used as a photocatalyst to degrade antibiotic pollutants in water under visible light. Description of the Drawings
[0018] Figure 1 This is the transmission electron microscope photograph of the present invention, where the scale bar length is 5 nm;
[0019] Figure 2 This is the high-magnification X-ray photoelectron spectrum of the Mo element of the product of the present invention and ordinary niobium pentoxide;
[0020] Figure 3 This is the Mott-Schottky test result diagram of the product of the present invention and ordinary niobium pentoxide;
[0021] Figure 4 This is the comparison diagram of the degradation rates of the product of the present invention and ordinary niobium pentoxide against antibiotics under visible light illumination conditions. Detailed implementation manners
[0022] To further understand the features, technical means, specific purposes, and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.
[0023] Example 1
[0024] S1. Dissolve 6 grams of niobium oxalate in a mixed solvent of 20 mL of deionized water and 25 mL of polyethylene glycol, magnetically stir at room temperature for 20 minutes while gradually adding 5 mL of a 1 mol / L L-arginine solution dropwise, and then ultrasonically treat the mixed solution for 20 minutes. The mixing ratio of deionized water to polyethylene glycol solvent is 1:1 - 3.
[0025] S2. Add 28% ammonia water by mass concentration to the solution after ultrasonic treatment, adjust the pH of the solution to 7.5 until a white flocculent precipitate is formed, then transfer it to a reaction kettle for hydrothermal reaction at 150 °C for 12 hours. The solution after hydrothermal reaction cooling is placed in an 85 °C drying oven until a dry sample is obtained. Put the dried and ground powder into a muffle furnace and heat it to 480 °C at a heating rate of 4 °C per minute, keep it warm for 4 hours and then naturally cool to room temperature to obtain the precursor.
[0026] S3. Weigh 4.0 grams of the prepared precursor, add it together with 0.16 grams of ammonium molybdate to hot water at 80 °C, stir in a water bath for 2 hours, and heat in an oven at 80 °C for 24 hours until it is evaporated to dryness to obtain blue crystals.
[0027] S4. Grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere, with a nitrogen flow rate of 30 mL / min, heat the tubular furnace to 500 °C at a heating rate of 5 °C per minute, keep it warm for 4 hours and then naturally cool to room temperature, and carry out mixed calcination on the mixed niobium oxalate and ammonium molybdate to obtain the target product, which is a p-type niobium pentoxide catalyst.
[0028] Example 2
[0029] S1, 8 g of niobium oxalate was dissolved in a mixed solvent of 25 mL of deionized water and 30 mL of polyethylene glycol, and 6 mL of a 1 mol / L L-arginine solution was added dropwise under magnetic stirring at room temperature for 22 minutes. The mixed solution was then ultrasonicated for 25 minutes.
[0030] S2, add 28% ammonia water to the solution after ultrasonic treatment, adjust the pH of the solution to 8.0, until a white flocculent precipitate is formed, and then transfer it to a reactor for hydrothermal reaction at 200°C for 13 hours. The solution after the hydrothermal reaction is cooled is placed in a drying oven at 90°C until a dry sample is obtained. The powder obtained by drying and grinding is placed in a muffle furnace and calcined at a heating rate of 3°C per minute to 500°C. After keeping warm for 5 hours, it is naturally cooled to room temperature to obtain a precursor.
[0031] S3. Weigh 4.5 g of the prepared precursor and add it together with 0.17 g of ammonium molybdate to 85° C. hot water. Stir in a water bath for 2 hours. Heat in an oven at 85° C. for 26 hours until evaporated to dryness to obtain blue crystals.
[0032] S4, grinding the precipitated blue crystals into powder, placing them in a crucible, covering it, and placing it in a nitrogen atmosphere with a nitrogen flow rate of 30 mL / min. The temperature was raised to 520°C in a tubular furnace at a rate of 5°C per minute, and then naturally cooled to room temperature after keeping the temperature for 4 hours to obtain a p-type niobium pentoxide catalyst.
[0033] Example 3
[0034] S1, 7 g of niobium oxalate was dissolved in a mixed solvent of 28 mL of deionized water and 30 mL of polyethylene glycol, and 6 mL of a 1 mol / L L-arginine solution was added dropwise under magnetic stirring at room temperature for 25 minutes. The mixed solution was then ultrasonicated for 25 minutes.
[0035] S2, add 28% ammonia water to the solution after ultrasonic treatment, adjust the pH of the solution to 8.5, until a white flocculent precipitate is formed, and then transfer it to a reactor for hydrothermal reaction at 200°C for 15 hours. The solution after the hydrothermal reaction is cooled is placed in a drying oven at 90°C until a dry sample is obtained. The powder obtained by drying and grinding is placed in a muffle furnace and calcined at a heating rate of 4°C per minute to 500°C. After keeping warm for 5 hours, it is naturally cooled to room temperature to obtain a precursor.
[0036] S3. Weigh 4.0 g of the prepared precursor and add it together with 0.16 g of ammonium molybdate to 80° C. hot water. Stir in a water bath for 2 hours. Heat in an oven at 80° C. for 24 hours until evaporated to dryness to obtain blue crystals.
[0037] S4. Grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere with a nitrogen flow rate of 30 mL / min, heat the tubular furnace to 500 °C at a heating rate of 5 °C per minute, keep it warm for 4 hours, and then naturally cool it to room temperature to obtain the p-type niobium pentoxide catalyst.
[0038] Example 4
[0039] S1. Dissolve 10 g of niobium oxalate in a mixed solvent of 20 mL of deionized water and 40 mL of polyethylene glycol, stir magnetically at room temperature for 20 minutes while dropwise adding 5 mL of a 1 mol / L L-arginine solution, and then ultrasonically treat the mixed solution for 20 minutes.
[0040] S2. Add 28% ammonia water by mass concentration to the solution after ultrasonic treatment, adjust the pH of the solution to 8.0 until a white flocculent precipitate is formed, then transfer it to a reaction kettle for hydrothermal reaction at 150 °C for 12 hours. Place the solution after hydrothermal reaction cooling in an 85 °C drying oven until a dry sample is obtained. Put the dried and ground powder into a muffle furnace and heat it to 480 °C at a heating rate of 4 °C per minute for calcination, keep it warm for 4 hours, and then naturally cool it to room temperature to obtain the precursor.
[0041] S3. Weigh 5.0 g of the prepared precursor, add it together with 0.20 g of ammonium molybdate to hot water at 80 °C, stir in a water bath for 2 hours, and heat it in an oven at 80 °C for 24 hours until it is evaporated to dryness to obtain blue crystals.
[0042] S4. Grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere with a nitrogen flow rate of 30 mL / min, heat the tubular furnace to 500 °C at a heating rate of 5 °C per minute, keep it warm for 4 hours, and then naturally cool it to room temperature to obtain the target product.
[0043] Example 5
[0044] S1. Dissolve 12 g of niobium oxalate in a mixed solvent of 30 mL of deionized water and 80 mL of polyethylene glycol, stir magnetically at room temperature for 20 minutes while dropwise adding 6 mL of a 1 mol / L L-arginine solution, and then ultrasonically treat the mixed solution for 20 minutes.
[0045] S2. Add 28% ammonia water by mass concentration to the solution after ultrasonic treatment, adjust the pH of the solution to 8.0 until a white flocculent precipitate is formed, then transfer it to a reaction kettle for hydrothermal reaction at 150 °C for 12 hours. Place the solution after hydrothermal reaction cooling in an 85 °C drying oven until a dry sample is obtained. Put the dried and ground powder into a muffle furnace and heat it to 480 °C at a heating rate of 4 °C per minute for calcination, keep it warm for 4 hours, and then naturally cool it to room temperature to obtain the precursor.
[0046] S3. Weigh 5.0 g of the prepared precursor and add it together with 0.20 g of ammonium molybdate to 80° C. hot water. Stir in a water bath for 2 hours. Heat in an oven at 80° C. for 24 hours until evaporated to dryness to obtain blue crystals.
[0047] S4, grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere, and use a nitrogen flow rate of 30 mL / min. Heat the temperature in a tubular furnace to 500°C at a rate of 5°C per minute, keep it at that temperature for 4 hours, and then naturally cool it to room temperature to obtain the target product.
[0048] Embodiment 6
[0049] S1, dissolving 12 g of niobium oxalate in a mixed solvent of 40 mL of deionized water and 120 mL of polyethylene glycol, magnetically stirring at room temperature for 25 minutes while adding 6 mL of a 1 mol / L L-arginine solution dropwise, and then ultrasonicating the mixed solution for 20 minutes.
[0050] S2. Add 28% ammonia water to the solution after ultrasonic treatment, adjust the pH of the solution to 8.0, until a white flocculent precipitate is formed, and then transfer it to a reactor for hydrothermal reaction at 150°C for 12 hours. The solution after the hydrothermal reaction is cooled is placed in a drying oven at 85°C until a dry sample is obtained. The powder obtained by drying and grinding is placed in a muffle furnace and calcined at a heating rate of 4°C per minute to 480°C. After keeping warm for 4 hours, it is naturally cooled to room temperature to obtain a precursor.
[0051] S3. Weigh 5.0 g of the prepared precursor and add it together with 0.20 g of ammonium molybdate to 80° C. hot water. Stir in a water bath for 2 hours. Heat in an oven at 80° C. for 24 hours until evaporated to dryness to obtain blue crystals.
[0052] S4, grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere, and use a nitrogen flow rate of 30 mL / min. Heat the temperature in a tubular furnace to 500°C at a rate of 5°C per minute, keep it at that temperature for 4 hours, and then naturally cool it to room temperature to obtain the target product.
[0053] Embodiment 7
[0054] S1, 5 g of niobium oxalate was dissolved in a mixed solvent of 10 mL of deionized water and 15 mL of polyethylene glycol, and 5 mL of a 1 mol / L L-arginine solution was added dropwise under magnetic stirring at room temperature for 20 minutes. The mixed solution was then ultrasonicated for 20 minutes.
[0055] S2. Add 28% ammonia water to the solution after ultrasonic treatment, adjust the pH of the solution to 8.5, until a white flocculent precipitate is formed, and then transfer it to a reactor for hydrothermal reaction at 155°C for 10 hours. The solution after the hydrothermal reaction is cooled is placed in a drying oven at 85°C until a dry sample is obtained. The powder obtained by drying and grinding is placed in a muffle furnace and calcined at a heating rate of 4°C per minute to 480°C. After keeping warm for 4 hours, it is naturally cooled to room temperature to obtain a precursor.
[0056] S3. Weigh 4.0 g of the prepared precursor and add it together with 0.16 g of ammonium molybdate to 80° C. hot water. Stir in a water bath for 2 hours. Heat in an oven at 80° C. for 24 hours until evaporated to dryness to obtain blue crystals.
[0057] S4, grind the precipitated blue crystals into powder, place them in a crucible, cover it, place it in a nitrogen atmosphere, and use a nitrogen flow rate of 30 mL / min. Heat the temperature in a tubular furnace to 500°C at a rate of 5°C per minute, keep it at that temperature for 4 hours, and then naturally cool it to room temperature to obtain the target product.
[0058] Comparative Example
[0059] Ordinary niobium pentoxide of conventional non-doped system was selected as the comparison material.
[0060] The prepared p-type niobium pentoxide catalyst was tested.
[0061] Conduct semiconductor performance testing.
[0062] The obtained product was characterized by high-precision morphology using a transmission electron microscope. Doping leads to lattice changes. The niobium pentoxide obtained in Example 1 is a doping system. Figure 1 As shown in the figure, the obtained product and the ordinary niobium pentoxide of the non-doped system were characterized by X-ray photoelectron spectroscopy. The high-magnification X-ray photoelectron spectroscopy of Mo element showed that the obtained product had Mo element introduced, while the ordinary niobium pentoxide did not have Mo element introduced. As shown in the attached figure, Figure 2 As shown in the figure, the semiconductor properties of the obtained product and ordinary niobium pentoxide were analyzed using the Mott-Schottky test results. The results showed that the semiconductor properties of the obtained product changed from n-type semiconductor to p-type semiconductor, while the ordinary niobium pentoxide did not change. Figure 3 As shown in . It can be seen that after being prepared according to the present invention, it has better semiconductor performance.
[0063] Perform photocatalytic tests.
[0064] Preparation of photocatalytic reaction sample dish: Weigh 50 mg of the prepared product into a beaker, add 15 mL of deionized water, ultrasonically disperse for 20 min, then pour it into a petri dish with a diameter of 10 cm, so that the sample is evenly dispersed at the bottom of the petri dish, and then dry it in an oven at 60 °C.
[0065] The photocatalytic performance of the sample was mainly evaluated by photocatalytic degradation of tetracycline hydrochloride (TH) in a reactor. The reactor was made of quartz glass with a volume of 4.5 L (30 cm × 15 cm × 10 cm [L × W × H]). A xenon lamp (λ>420 nm, 14 W m -2 ) was placed 15 cm to the left of the reactor. Before the photocatalytic experiment, 10 mL of the pre-prepared tetracycline hydrochloride solution with a concentration of 50 mg / L was fixed to 100 mL and poured into the reactor to be mixed with the p-type niobium pentoxide sample powder. The reactor containing the mixed solution was placed on a magnetic stirrer. Under the condition of no light, the mixed solution and the sample were evenly stirred by the magnetic stirrer to reach the adsorption and desorption equilibrium. After 20 minutes, the power of the xenon lamp was turned on for testing, and the extracted degradation solution was analyzed for concentration by a high performance liquid chromatograph.
[0066] The degradation rates of the obtained product and ordinary niobium pentoxide for tetracycline hydrochloride under visible light irradiation are shown in the appendix Figure 4 As shown, it can be rapidly degraded within 20 minutes, while the degradation rate of ordinary niobium pentoxide is significantly slower. After 20 minutes, the degradation rate is relatively slow. For ordinary niobium pentoxide, there is no change, and the overall degradation degree is relatively limited, and effective and thorough degradation cannot be achieved.
[0067] From the above tests, it can be seen that the p-type niobium pentoxide catalyst prepared by the present invention can effectively degrade antibiotic pollutants in water under visible light.
[0068] It should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for preparing a catalyst doped with niobium pentoxide semiconductor, characterized in that, The method includes the following steps: S1. Prepare a mixed solution. Add niobium oxalate to a polyethylene glycol solvent to obtain a preliminary mixed solution. While stirring the preliminary mixed solution, add an L-arginine solution, and then obtain a mixed solution after ultrasonic treatment. Among them, niobium oxalate and the polyethylene glycol solvent are proportioned according to the ratio of adding 3-10 ml of polyethylene glycol solvent per 1 g of niobium oxalate; S2. Add ammonia water to the mixed solution, adjust the mixed solution to be alkaline until a white flocculent precipitate is formed, then transfer it to a reaction kettle for hydrothermal reaction. After the reaction is completed, cool it, place it in a drying oven to dry until a dry sample is obtained. Dry and grind the sample to obtain a powder, put it into a muffle furnace for calcination, keep the temperature for a certain time and then cool it to room temperature to obtain a precursor; S3. Weigh the precursor and ammonium molybdate, add them together to hot water, stir in a water bath, and heat in an oven until it is evaporated to dryness to obtain blue crystals. Among them, the mass ratio of the precursor to ammonium molybdate is 20-50:1-2; S4. Grind the precipitated blue crystals into powder, place them in a crucible, cover it, and heat and raise the temperature under an inert gas atmosphere. After keeping the temperature for a certain time, naturally cool it to room temperature to obtain a p-type niobium pentoxide catalyst.
2. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, wherein, In the step S1, the L-arginine solution is an L-arginine solution.
3. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 2, wherein, In the step S1, the L-arginine solution and the preliminary mixed solution are added according to a volume ratio of 1-2:9-15, and the concentration of the L-arginine solution is 1 mol / L.
4. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, In the step S1, the preliminary mixed solution is magnetically stirred at room temperature for 15-25 minutes and ultrasonically treated for 15-25 minutes.
5. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, In the step S2, the mass concentration of ammonia water is 28%.
6. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, In the step S2, the hydrothermal reaction in the reaction kettle is carried out at 150-200 °C for 10-15 hours, the temperature of the drying oven is kept at 85-90 °C, and the temperature in the muffle furnace is raised to 480 °C - 500 °C at a heating rate of 3-5 °C per minute for calcination, and after keeping the temperature for 4-6 hours, it is naturally cooled to room temperature.
7. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, wherein In the hydrothermal reaction of the step S3, the temperature of the hot water is kept between 80 °C - 95 °C, and the water bath is stirred for 2-3 hours.
8. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, In the step S3, when drying, the temperature of the oven is kept between 80-90 °C and heated for 20-30 hours.
9. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, The inert gas atmosphere is a nitrogen atmosphere, the nitrogen flow rate is 30 mL / min, the temperature is raised to 500 °C - 550 °C at a heating rate of 5 °C - 6 °C per minute, and after keeping the temperature for 4-6 hours, it is naturally cooled to room temperature.
10. The method for preparing a catalyst doped with niobium pentoxide semiconductor according to claim 1, characterized in that, In the step S2, the pH of the mixed solution is adjusted to 7.5-8.5.