A boron-tungsten co-doped titanium dioxide catalyst, a preparation method and application thereof
Patent Information
- Application Number
- CN202611371691.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-05
- Publication Date
- 2026-10-27
AI Technical Summary
[0003]但纯TiO2在实际应用中存在明显缺陷：禁带宽度较大（约3.2eV），仅能吸收紫外区光，对太阳光利用率不足5%；同时光生电子与空穴复合率高，可见光下催化活性极低，难以满足大规模水处理需求
[0022]（1）本发明硼钨共掺杂改性的TiO2催化剂分别在价带和导带上形成杂质能级，二者均能降低TiO2材料的禁带宽度。加入对有机物具有强溶解性的DMF后使得钛酸四丁酯的水解产物得以脱离，再通过乙二醇的极性将有机残留洗涤除去，这能使得催化剂表面产生更少的有机残留。
Smart Images
Figure CN122974305A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, and specifically relates to a boron-tungsten co-doped titanium dioxide catalyst, its preparation method, and its application. Background Technology
[0002] Photocatalytic oxidation technology has attracted much attention in the field of environmental governance due to its advantages such as degrading organic pollutants at room temperature and pressure without secondary pollution. Titanium dioxide (TiO2), as a classic photocatalytic material, has the characteristics of good chemical stability, non-toxicity, low cost, and excellent ultraviolet light response, and is widely used in the degradation of organic pollutants in water and air purification.
[0003] However, pure TiO2 has significant drawbacks in practical applications: its large band gap (approximately 3.2 eV) limits its absorption to ultraviolet light, resulting in a solar light utilization rate of less than 5%; simultaneously, its high recombination rate of photogenerated electrons and holes leads to extremely low catalytic activity under visible light, making it unsuitable for large-scale water treatment. To broaden its photoresponse range and improve catalytic efficiency, researchers have modified TiO2 through elemental doping, heterojunction construction, morphology control, and surface photosensitization.
[0004] Elemental doping is an effective way to improve the photocatalytic performance of TiO2. Non-metallic doping can form intermediate energy levels above the valence band of TiO2, while metallic doping can introduce impurity energy levels within the band gap; both can narrow the band gap and enhance visible light absorption. However, single-element doping has limited effect on improving carrier separation efficiency and is prone to problems such as uneven doping and excessive lattice defects, resulting in insufficient improvement in catalytic performance.
[0005] Metal-nonmetal co-doping can leverage the synergistic effects between different elements to simultaneously achieve narrowing of the band gap, increase of specific surface area, and enhanced separation efficiency of photogenerated carriers, making it a research hotspot for TiO2 modification. Existing co-doped TiO2 is mostly prepared using hydrothermal and deposition methods, which suffer from complex processes, long production cycles, uncontrollable crystal growth, and difficulty in industrialization. Furthermore, some doped systems are costly, have poor stability, and exhibit significant activity decay after repeated use.
[0006] Currently, there is still a lack of a metal-nonmetal co-doped TiO2 catalyst preparation technology that is simple to implement, operates under mild conditions, is low in cost, can be mass-produced, and possesses both high visible light activity and good cycling stability. Therefore, this invention provides a boron-tungsten co-doped titanium dioxide catalyst and its preparation method to overcome the deficiencies in existing technologies. Summary of the Invention
[0007] To address the problems in the background art, this invention proposes a boron-tungsten co-doped titanium dioxide catalyst, its preparation method, and its application. The boron-tungsten co-doped TiO2 catalyst forms impurity energy levels in both the valence and conduction bands, both of which reduce the band gap of the TiO2 material. The addition of DMF, which has strong solubility for organic matter, allows the hydrolysis products of tetrabutyl titanate to be removed, and the organic residues are then washed away using the polarity of ethylene glycol, resulting in fewer organic residues on the catalyst surface.
[0008] The technical solution adopted by this invention to solve its technical problem is: to provide a method for preparing a boron-tungsten co-doped titanium dioxide catalyst, comprising the following steps:
[0009] S1. Mix and stir anhydrous ethanol with tetrabutyl titanate;
[0010] S2. Mix and stir anhydrous ethanol, ammonium metatungstate and boric acid;
[0011] S3. Add the mixture obtained in S2 dropwise into the solution obtained in S1 and stir.
[0012] S4. Let the mixture obtained in S3 stand and age to obtain a colorless and transparent sol. After aging, crush the sol.
[0013] S5. Add the sol to anhydrous ethanol heated in a water bath, wash with ethylene glycol, and dry in a vacuum oven at 80°C to obtain the TiO2 precursor.
[0014] S6. The precursor is placed in a muffle furnace and calcined to obtain a boron-tungsten co-doped titanium dioxide catalyst.
[0015] Furthermore, the volume ratio of tetrabutyl titanate, anhydrous ethanol, ammonium metatungstate, boric acid and pure water is (15-25):(30-40):(0.5-1):(0.5-2):(3-8).
[0016] Furthermore, in step S1, a water bath is used to prepare the gel, and the water bath treatment time is 24h-36h.
[0017] Furthermore, in step S2, the calcination temperature in the muffle furnace is 500℃-600℃; the heating rate of the muffle furnace is 5-10℃ / min; and the calcination time in the muffle furnace is 2-3h.
[0018] Furthermore, the stirring time for S1, S2, and S3 is 28-32 minutes.
[0019] A boron-tungsten co-doped titanium dioxide catalyst is prepared by the above-described preparation method.
[0020] Such as the above-mentioned application of boron-tungsten co-doped titanium dioxide catalyst in the photocatalytic degradation of organic pollutants.
[0021] The beneficial effects of this invention are:
[0022] (1) The boron-tungsten co-doped TiO2 catalyst of the present invention forms impurity energy levels in the valence band and conduction band, respectively, both of which can reduce the band gap of TiO2 material. The addition of DMF, which has strong solubility for organic matter, allows the hydrolysis products of tetrabutyl titanate to be removed, and the organic residues are then washed away by the polarity of ethylene glycol, which can result in less organic residues on the catalyst surface.
[0023] (2) With the co-doping of W and B, the size of TiO2 particles in the catalyst of the present invention is reduced, and the pore volume and specific surface area of the sample are greatly improved.
[0024] (3) The product prepared by the present invention can be used to degrade organic matter, especially methylene blue, with a degradation rate of over 82%.
[0025] (4) The boron-tungsten co-doped titanium dioxide catalyst prepared by the present invention can be recycled and reused, and still has a high degradation rate after repeated use. Attached Figure Description
[0026] Figure 1 These are the XRD spectra of boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5 of this invention;
[0027] Figure 2 These are the fluorescence spectra of boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5 of this invention. Detailed Implementation
[0028] The technical solutions of the embodiments of the invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining the invention and not for limiting the invention. Furthermore, it should be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings, not all of the structures.
[0029] In the experiments described in Examples 1-6 below, the prepared boron-tungsten co-doped titanium dioxide was used to degrade methylene blue. The specific experimental procedures are as follows:
[0030] 0.05 g of the prepared product was uniformly dispersed in 50 mL of a 40 mg / L methylene blue solution and irradiated with a 75 W xenon lamp. Samples were taken for analysis after 2 hours. The absorbance of methylene blue was measured using a UV spectrophotometer at the maximum absorption wavelength 1max = 664 nm. The degradation rate was calculated using the formula: D = [(Ao - A;)Ao] × 100%; where D is the degradation rate, Ao is the absorbance of the sample before irradiation, and A is the absorbance of the sample after 2 hours of irradiation.
[0031] Example 1
[0032] Step 1: Add 0.05g of the weighed, washed 2% B / 3.5% W-TiO2 catalyst and 50mL of 40mg / L MB solution to a 100mL photocatalytic reaction condenser beaker.
[0033] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0034] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0035] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0036] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 60%.
[0037] Example 2
[0038] Step 1: Add 0.05g of the weighed, washed 3% B / 3.5% W-TiO2 catalyst and 50mL of 40mg / LMB solution to a 100mL photocatalytic reaction condenser beaker.
[0039] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0040] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0041] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0042] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 62%.
[0043] Example 3
[0044] Step 1: Add 0.05g of the weighed, washed 5% B / 3.5% W-TiO2 catalyst and 50mL of 40mg / LMB solution to a 100mL photocatalytic reaction condenser beaker.
[0045] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0046] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0047] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0048] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 82.45%.
[0049] Example 4
[0050] Step 1: Add 0.05g of the weighed, washed 7%B / 3.5%W-TiO2 catalyst and 50mL of 40mg / LMB solution to a 100mL photocatalytic reaction condenser beaker.
[0051] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0052] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0053] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0054] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 70%.
[0055] Example 5
[0056] Step 1: Add 0.05g of the weighed, washed 8% B / 3.5% W-TiO2 catalyst and 50mL of 40mg / LMB solution to a 100mL photocatalytic reaction condenser beaker.
[0057] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0058] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0059] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0060] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 56%.
[0061] Example 6
[0062] Step 1: Add 0.05g of the weighed, washed 8% B / 3.5% W-TiO2 catalyst and 50mL of 40mg / LMB solution to a 100mL photocatalytic reaction condenser beaker.
[0063] Step 2: Turn on the condenser and stirrer to carry out the light-protected adsorption-desorption equilibrium reaction. After 30 minutes, turn on the light to end the light protection process.
[0064] Step 3: Starting from the end of the dark treatment, take 6.5 ml of solution every 20 min and test its absorbance (MB test wavelength λ=664 nm). After the test, take out the liquid, shake it well, pour it back into the condenser beaker, and record its absorbance data.
[0065] Step 4: After the process is complete, turn off the power supply first, then turn off the gas supply. After the reactor cools to room temperature, collect the catalyst.
[0066] Step 5: The boron-tungsten co-doped titanium dioxide photocatalyst prepared in this embodiment was used to degrade 40 mg / L methylene blue. The degradation rate was tested to be 44%.
[0067] XRD and fluorescence spectroscopy were performed on the boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5, and the results are as follows: Figure 1 , Figure 2 As shown.
[0068] like Figure 1The image shows the XRD patterns of boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5. The horizontal axis represents the 2θ diffraction angle (°), and the vertical axis represents the diffraction intensity. The patterns include six curves: PureTiO2, 2%B / 3.5%W-TiO2, 3%B / 3.5%W-TiO2, 5%B / 3.5%W-TiO2, 7%B / 3.5%W-TiO2, and 8%B / 3.5%W-TiO2. Figure 1 It can be seen that pure TiO2 exhibits typical anatase crystal diffraction peaks; after boron-tungsten co-doping, the position of the characteristic peaks of TiO2 remains basically unchanged, while the peak width increases slightly and the peak intensity decreases. This indicates that the doping of boron and tungsten elements did not destroy the original crystal form of TiO2, but at the same time refined the TiO2 grains and slightly reduced the crystallinity, which is beneficial to increasing the specific surface area of the catalyst.
[0069] like Figure 2 The image shows the fluorescence spectra of boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5. The horizontal axis represents wavelength (nm), and the vertical axis represents fluorescence intensity. The spectra include six curves: PureTiO2, 2%B-3.5%W-TiO2, 3%B-3.5%W-TiO2, 5%B-3.5%W-TiO2, 7%B-3.5%W-TiO2, and 8%B-3.5%W-TiO2. Figure 2 It can be seen that pure TiO2 has the highest fluorescence signal intensity. With the change of boron-tungsten co-doping ratio, the fluorescence intensity of the samples all decreased significantly. Among them, 5%B / 3.5%W-TiO2 has the lowest fluorescence intensity, indicating that the photogenerated carrier recombination rate is the lowest and the carrier separation efficiency is the best under this doping ratio, which is consistent with the photocatalytic activity test results.
[0070] Experimental Example 1:
[0071] The oxygen-deficient titanium dioxide prepared in Example 3 was used to degrade 40 mg / L methylene blue, and the degradation rate of methylene blue at different time points was tested.
[0072] Pure titanium dioxide was used to degrade 40 mg / L methylene blue, and the degradation rate of methylene blue at different time points was tested.
[0073] The test method is as follows: 0.05g of the product is uniformly dispersed in 50mL of a 40mg / L methylene blue solution and irradiated with a 75W xenon lamp. min Subsequent sampling and analysis were performed using a UV spectrophotometer at the maximum absorption wavelength λ. max The absorbance of methylene blue was measured at 664 nm. The degradation rate was calculated using the formula: D = [(Ao - A) / Ao] × 100%; where D is the degradation rate, Ao is the absorbance of the sample before illumination, and A is the illumination time t. min The absorbance of the sample at that time.
[0074] XRD and fluorescence spectroscopy were performed on the boron-tungsten co-doped titanium dioxide and pure TiO2 prepared in Examples 1-5.
[0075] XRD results are as follows Figure 1 As shown: pure TiO2 exhibits typical anatase characteristic peaks; after boron-tungsten co-doping, the position of the characteristic peaks remains basically unchanged, the peak width increases slightly, and the intensity decreases, indicating that doping does not destroy the TiO2 crystal structure, refines the grains, and slightly reduces the crystallinity, which is beneficial to increasing the specific surface area.
[0076] The photocatalytic activities are shown in Table 1:
[0077] Table 1 shows the degradation rate (%) of methylene blue by different catalysts.
[0078]
[0079] The catalysts in Examples 1-5 showed significantly higher degradation rates of methylene blue than pure TiO2 (12%); Example 3 showed the best degradation rate, reaching 82.45% after 120 min, consistent with the characterization results. It can be seen that boron-tungsten co-doped titanium dioxide exhibits significantly improved catalytic performance, consistent with the aforementioned characterization results.
[0080] Experimental Example 2:
[0081] In Example 3, the boron-tungsten co-doped titanium dioxide used in step 5 needs to be centrifuged, the precipitate washed three times with deionized water, dried overnight at 65°C, and then used to degrade 40 mg / L methylene blue. The degradation rate after the first repetition is tested. The used boron-tungsten co-doped titanium dioxide needs to be centrifuged, the precipitate washed three times with deionized water, dried overnight at 65°C, and then used to degrade 40 mg / L methylene blue. The degradation rate after the second repetition is tested. The used boron-tungsten co-doped titanium dioxide needs to be centrifuged, the precipitate washed three times with deionized water, dried overnight at 65°C, and then used to degrade 40 mg / L methylene blue. The degradation rate after the third repetition is tested. The used boron-tungsten co-doped titanium dioxide needs to be centrifuged, the precipitate washed three times with deionized water, dried overnight at 65°C, and then used to degrade 40 mg / L methylene blue. The degradation rate after the third repetition is tested.
[0082] The test method was the same as in Experiment 1. The results of each repetition are shown in Table 2.
[0083] Table 2 shows the stability (degradation rate, %) of the catalyst in Example 3 during recycling.
[0084]
[0085] As can be roughly seen from Table 2, the catalyst still achieved a degradation rate of up to 74% for MB solution after four repeated cycles, demonstrating good stability.
[0086] In summary, the above embodiments and experimental results demonstrate that the boron-tungsten co-doped titanium dioxide catalyst prepared by the sol-gel method of this invention is simple, operates under mild conditions, is low in cost, and is easily mass-produced. The synergistic doping of boron and tungsten effectively modulates the electronic structure of titanium dioxide, narrows the band gap, broadens the visible light response range, significantly improves the specific surface area and photogenerated carrier separation efficiency, and greatly enhances photocatalytic activity. Among these, the 5%B / 3.5%W-TiO2 catalyst exhibits the best catalytic performance, achieving a degradation rate of 82.45% for methylene blue within 120 minutes, and maintaining a degradation rate of 74% after four cycles, demonstrating excellent catalytic activity and cycle stability. The catalyst prepared by this invention can efficiently degrade organic pollutants in water bodies and has good application prospects and promotional value in the field of environmental remediation.
[0087] The present invention has been described in detail above with reference to embodiments and comparative examples. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.
Claims
1. A method for preparing a boron-tungsten co-doped titanium dioxide catalyst, characterized in that, Includes the following steps: S1. Mix and stir anhydrous ethanol with tetrabutyl titanate; S2. Mix and stir anhydrous ethanol, ammonium metatungstate and boric acid; S3. Add the mixture obtained in S2 dropwise into the solution obtained in S1 and stir. S4. Let the mixture obtained in S3 stand and age to obtain a colorless and transparent sol. After aging, crush the sol. S5. Add the sol to anhydrous ethanol heated in a water bath, wash with ethylene glycol, and dry in a vacuum oven at 80°C to obtain the TiO2 precursor. S6. The TiO2 precursor is placed in a muffle furnace and calcined to obtain a boron-tungsten co-doped titanium dioxide catalyst.
2. The method for preparing a boron-tungsten co-doped titanium dioxide catalyst according to claim 1, characterized in that, The volume ratio of tetrabutyl titanate, anhydrous ethanol, ammonium metatungstate, boric acid and pure water is (15-25):(30-40):(0.5-1):(0.5-2):(3-8).
3. The method for preparing a boron-tungsten co-doped titanium dioxide catalyst according to claim 1, characterized in that, In step S1, a gel is prepared by heating in a water bath for 24-36 hours.
4. The method for preparing a boron-tungsten co-doped titanium dioxide catalyst according to claim 1, characterized in that, In step S2, the calcination temperature in the muffle furnace is 500℃-600℃; the heating rate of the muffle furnace is 5-10℃ / min; and the calcination time in the muffle furnace is 2-3h.
5. The method for preparing a boron-tungsten co-doped titanium dioxide catalyst according to claim 1, characterized in that, The stirring time for S1, S2 and S3 is 28-32 minutes.
6. A boron-tungsten co-doped titanium dioxide catalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.
7. The application of the boron-tungsten co-doped titanium dioxide catalyst as described in claim 6 in the photocatalytic degradation of organic pollutants.