A Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst and preparation method and application thereof
The Nb2O5/W18O49 heterojunction nanofiber photocatalyst was prepared by electrospinning and solvothermal method, which solved the problem of low photocatalytic CO2 reduction efficiency and achieved high efficiency in photocatalytic activity and CO2 reduction performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-01
- Publication Date
- 2026-03-20
AI Technical Summary
Existing photocatalysts are not efficient in the photocatalytic CO2 reduction process, mainly due to the instability of the CO2 molecule structure and the rapid recombination of photogenerated electrons and holes, resulting in low carrier separation efficiency. No relevant reports have been found on existing Nb2O5/W18O49 heterojunction nanofiber materials.
A Nb2O5/W18O49 heterojunction nanofiber photocatalyst was prepared by combining electrospinning and solvothermal methods. The Nb2O5 nanofiber mesh was formed by electrospinning and then combined with the W18O49 precursor solution in a solvothermal reaction to form a heterojunction structure, thereby improving the carrier separation efficiency.
It significantly improved the visible light response and photocatalytic activity of the catalyst, enhanced CO2 reduction activity and CO selectivity, achieved effective separation of photogenerated electrons and holes, and improved photocatalytic reduction capability.
Smart Images
Figure CN118105970B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of photocatalytic materials, and particularly relates to a Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst and preparation method and application thereof. BACKGROUND
[0002] As a green chemical method, photocatalytic technology has attracted extensive attention. Converting CO2 into valuable fuels and chemical raw materials such as CO, HCHO, CH3OH and CH4 through solar energy is a promising solution to the challenge. However, due to the stable structure of CO2 molecules, the rapid recombination of photo-generated electrons and holes, and the limitations of band structure and surface properties, the efficiency of photocatalytic CO2 reduction is not ideal. Therefore, it is crucial to construct an efficient photocatalyst.
[0003] As an excellent n-type transition metal oxide semiconductor photocatalyst, niobium pentoxide (Nb2O5) has a suitable band gap structure and thermodynamic stability, and is widely used in the fields of photocatalysis and supercapacitors. Monoclinic blue tungsten oxide (WO3) is an n-type narrow-band-gap transition metal oxide with good electron transport performance and light corrosion resistance. And there are a large number of oxygen vacancies in WO3, which provide a large number of active sites for photocatalytic reactions, thereby improving the photocatalytic activity. However, there is no related report on Nb2O5 / W 18 O 49 Heterojunction nanofiber materials as photocatalytic reduction of carbon dioxide. 18 O 49 18 O 49 SUMMARY
[0004] The application provides a Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst and preparation method and application thereof to solve the problems in the prior art.
[0005] The technical scheme adopted by the application is as follows: a Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst, and a preparation method thereof includes the following steps:
[0006] 1) Dissolve a niobium source and polyacrylonitrile (PAN) in N,N-dimethylformamide (DMF) to obtain a uniform and slightly yellow solution after sufficient stirring;
[0007] 2) Take the uniform and slightly yellow solution to perform electrospinning to obtain a PAN / niobium source nanofiber web felt;
[0008] 3) Put the PAN / niobium source nanofiber web in a porcelain boat for high-temperature calcination to obtain a Nb2O5 nanofiber photocatalyst;
[0009] 4) Put the Nb2O5 nanofiber photocatalyst obtained in step 3) into a W 18 O 49 precursor solution, and then place it in a reaction kettle to obtain a target product Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst through a solvothermal reaction.
[0010] The Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, wherein step 1) comprises the following steps: dissolving a niobium source in a DMF solution, stirring until completely dissolved, and then adding PAN powder, continuously stirring at room temperature for 12 h to obtain a uniform, yellowish solution.
[0011] The Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, wherein in step 1), the niobium source is niobium pentachloride.
[0012] The Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, wherein step 2) comprises the following steps: injecting the uniform, yellowish liquid into a syringe for electrospinning, the distance between the syringe needle tip and the collector is 15 cm, and a voltage of 15 kV is applied, and a dense PAN / niobium source nanofiber web is collected on an aluminum foil after 10 h.
[0013] The Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, wherein step 3) comprises the following steps: uniformly distributing the PAN / niobium source nanofiber web at the bottom of a porcelain boat, and then transferring it to a muffle furnace for high-temperature calcination, the heating rate is 1 ℃ / min, and the temperature is kept at 550 ℃ for 2 h, and the Nb2O5 nanofiber photocatalyst is obtained after natural cooling.
[0014] The Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, wherein in step 4), the W 18 O 49 precursor solution is prepared by the following steps: dissolving 0.2 g of tungsten hexachloride in 12 mL of anhydrous ethanol, stirring at room temperature for 30 min to obtain a W 18 O 49 precursor solution.
[0015] The Nb2O5 / W 18 O 49 The heterojunction nanofiber photocatalyst in step 4) is a solvothermal reaction at 160 DEG C for 6h.
[0016] The Nb2O5 / W 18 O 49 Application of the heterojunction nanofiber photocatalyst in photocatalytic reduction of carbon dioxide to carbon monoxide.
[0017] The application, the Nb2O5 / W 18 O 49 Application of the heterojunction nanofiber photocatalyst in photocatalytic reduction of carbon dioxide, the method is as follows: under normal temperature and pressure, Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst is added, vacuumized, high-purity carbon dioxide is introduced, and 300W xenon lamp is used for irradiation to reduce carbon dioxide.
[0018] The present application has the following advantages:
[0019] 1. The present application uses electrospinning and hot solvent method to prepare a Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst, which improves the separation efficiency of carriers, thereby significantly improving the visible light response of the catalyst and enhancing the photocatalytic activity.
[0020] 2. The Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst has enhanced CO2 reduction activity and CO selectivity under irradiation of ultraviolet-visible light, and the catalyst realizes effective spatial separation of photo-generated electrons with strong reduction ability on the conduction band of Nb2O5 and photo-generated holes with strong oxidation ability on the valence band of W 18 O 49 , thereby participating in the photocatalytic reaction.
[0021] 3. The Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst prepared by the present application has stronger photocatalytic reduction ability and participates in the catalytic reaction, which is an effective way to improve the visible light catalytic activity.
[0022] 4. The Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst prepared by the present application has good carbon dioxide reduction activity, and the method is simple, convenient, low-cost, mild in conditions and conducive to large-scale production. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 Pure Nb2O5 nanofiber photocatalyst prepared for Example 1, pure W 18 O 49 photocatalyst and Nb2O5 / W 18 O 49 XRD pattern of heterojunction nanofiber photocatalysis.
[0024] Figure 2 Pure Nb2O5 nanofiber photocatalyst prepared for Example 1, pure W 18 O 49 photocatalyst and Nb2O5 / W 18 O 49 Photocurrent test pattern of heterojunction nanofiber photocatalysis.
[0025] Figure 3 Nb2O5 nanofiber photocatalyst prepared for Example 1, pure W 18 O 49 photocatalyst and Nb2O5 / W 18 O 49 Carbon dioxide reduction activity pattern of heterojunction nanofiber photocatalysis. DETAILED DESCRIPTION
[0026] Example 1
[0027] (I) A method for preparing a Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst is as follows:
[0028] 1. 0.5 g of niobium pentachloride (NbCl5) was added to 10 mL of DMF, after stirring to completely dissolve, 1 g of PAN was added, and after stirring for 12 h, an electrospinning precursor solution was obtained.
[0029] 2. The electrospinning precursor solution obtained in step 1 was injected into a syringe, and spinning was performed on an electrospinning machine, the distance between the collector and the tip of the syringe was 15 cm, the applied voltage was 15 kV, and after 12 h, the fibers were collected. The obtained nanofiber web was transferred to a muffle furnace, the heating rate was 1 ℃ / min, calcination was carried out at 550 ℃ for 2 h, and natural cooling was carried out to room temperature, thereby obtaining Nb2O5 nanofibers.
[0030] 3. 0.2 g of tungsten hexachloride (WCl6) was dissolved in 12 mL of anhydrous ethanol, and after stirring to uniform, the solution color changed to blue, thereby obtaining a W 18 O 49 precursor solution.
[0031] 4. 30 mg of Nb2O5 nanofibers obtained in step 2 and W 18 O49 The precursor solution was placed together with the reaction vessel into a 20 mL reactor and subjected to solvothermal treatment at 160 °C for 6 h. After natural cooling to room temperature, the mixture was washed three times each with deionized water and anhydrous ethanol, and then dried at 60 °C for 6 h to obtain Nb₂O₅ / W. 18 O 49 Heterojunction nanofiber photocatalyst.
[0032] (II) Comparative Example 1 – The preparation method of pure Nb2O5 nanofiber photocatalyst is as follows:
[0033] 1. Add 0.5g of niobium pentachloride (NbCl5) to 10mL of DMF, stir until completely dissolved, then add 1g of PAN powder and stir for 12h to obtain an electrospinning precursor solution.
[0034] 2. The electrospinning precursor solution obtained in step 1 was injected into a syringe, and spinning was performed on an electrospinning machine. The distance between the collector and the syringe tip was 15 cm, and the applied voltage was 15 kV. The fibers were collected after 12 hours. The obtained mesh nanofibers were transferred to a muffle furnace, heated at a rate of 1 °C / min, calcined at 550 °C for 2 hours, and then naturally cooled to room temperature to obtain Nb₂O₅ nanofibers.
[0035] (III) Comparative Example 2 – Pure Sample W 18 O 49 The preparation method of nanofiber photocatalyst is as follows:
[0036] 0.2 g of tungsten hexachloride (WCl6) was dissolved in 12 mL of anhydrous ethanol and stirred until the solution turned blue. The solution was then poured into a 20 mL reaction vessel and solvated at 160 °C for 6 h. After natural cooling to room temperature, the mixture was washed three times each with deionized water and anhydrous ethanol, and dried at 60 °C for 6 h to obtain the synthesized pure sample W. 18 O 49 Nanofiber photocatalyst.
[0037] (iv) Material Characterization
[0038] Figure 1 The Nb2O5 nanofiber photocatalyst prepared in Example 1, W 18 O 49 Nanofiber photocatalysts and Nb2O5 / W 18 O 49 XRD pattern of heterojunction nanofiber photocatalyst. Figure 1 It can be seen that W 18 O 49The photocatalyst has three characteristic peaks at 23.5°, 25.9° and 35.6°, corresponding to the crystal faces (0 1 0), (-1 0 4) and (1 1 3) respectively; the Nb2O5 nanofiber photocatalyst has seven obvious characteristic diffraction peaks at 23.2°, 26.8°, 36.3°, 47.5°, 51.6°, 55.9° and 71.8°, which are respectively attributed to the (001), (180), (181), (002), (380), (182) and (382) crystal faces. In the Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst, the characteristic peaks of Nb2O5 and W 18 O 49 can be observed, indicating that the Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst is successfully synthesized.
[0039] Figure 2 The photocurrent test diagram of the pure Nb2O5 nanofiber photocatalyst prepared in Example 1, the pure W 18 O 49 photocatalyst and the Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst. It can be seen that the photocurrent density of the Nb2O5, W 18 O 49 , Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst has a four-cycle on / off photocurrent response curve, which shows that the photocurrent density of the prepared composite Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst is improved, indicating that more charges can participate in the photocatalytic reaction, thereby improving the catalytic activity.
[0040] Example 2
[0041] Application of a Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalyst in photocatalytic reduction of carbon dioxide
[0042] The method is as follows: under normal temperature and pressure, 20 mg of the Nb2O5 / W 18 O 49Heterojunction nanofiber photocatalyst, nitrogen was passed into the reactor at a flow rate of 50 mL / min for 30 min to remove air, and then high-purity carbon dioxide was continuously passed into the container for 30 min. The reaction vessel was irradiated using a 300W xenon lamp for photocatalytic testing, and 1000 μL of gas was drawn out every 60 min, and the amount of CO generated was quantitatively detected using a gas chromatograph.
[0043] Using the same method, the pure sample Nb2O5 nanofiber photocatalyst and the pure sample W 18 O 49 Nanofiber photocatalyst photocatalytic carbon dioxide reduction activity test.
[0044] Figure 3 The pure sample Nb2O5 nanofiber photocatalyst prepared in Example 1, the pure sample W 18 O 49 photocatalyst and Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalytic carbon dioxide reduction activity diagram. When the reaction time is 360 min, the Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalyst produces CO at a rate of 236.7 μmol / g, and the pure sample Nb2O5 nanofiber photocatalyst, the pure sample W 18 O 49 photocatalyst produces CO at a rate of 18.6 μmol / g, 24.9 μmol / g, respectively.
[0045] Through photocatalytic testing, the Nb2O5 / W 18 O 49 heterojunction nanofiber photocatalytic material shows higher carbon dioxide reduction performance.
Claims
1. A Nb2O5 / W 18 O 49 The application of heterojunction nanofiber photocatalysts in the photocatalytic reduction of carbon dioxide to carbon monoxide is characterized by... The method is as follows: Under normal temperature and pressure, add Nb2O5 / W 18 O 49 Heterojunction nanofiber photocatalysts were used, and after evacuation, high-purity carbon dioxide was introduced and irradiated with a 300 W xenon lamp to reduce the carbon dioxide. The Nb2O5 / W 18 O 49 The preparation method of heterojunction nanofiber photocatalyst includes the following steps: 1) Dissolve niobium pentachloride in DMF solution and stir until completely dissolved. Then add PAN powder and continue to stir magnetically at room temperature for 12 h to obtain a uniform, slightly yellow solution. 2) A uniform, slightly yellow liquid was injected into a syringe for electrospinning. The distance between the syringe needle tip and the collector was 15 cm, and a voltage of 15 kV was applied. After 10 h, a dense PAN / niobium source nanofiber mesh was collected on the aluminum foil. 3) The PAN / niobium source nanofiber mesh was evenly distributed on the bottom of the ceramic boat, and then transferred to a muffle furnace for high-temperature calcination. The heating rate was 1℃ / min, and the temperature was maintained at 550℃ for 2h. After natural cooling, the Nb2O5 nanofiber photocatalyst was obtained. 4) Place the 30 mg Nb2O5 nanofiber photocatalyst obtained in step 3) into W 18 O 49 The precursor solution was placed in a reaction vessel and subjected to a solvothermal reaction at 160°C for 6 hours to obtain the target product Nb₂O₅ / W. 18 O 49 Heterojunction nanofiber photocatalyst; The W 18 O 49 The preparation method of the precursor solution includes the following steps: 0.2 g of tungsten hexachloride is dissolved in 12 mL of anhydrous ethanol, and stirred at room temperature for 30 min to obtain W. 18 O 49 Precursor solution.