Preparation method of hydroxyl boron nitride fiber and propane oxidative dehydrogenation application of hydroxyl boron nitride fiber
By preparing hydroxy boron nitride fibers, the problem of catalyst sintering in the propane oxidative dehydrogenation process of boron nitride nanosheets was solved, achieving high stability and high catalytic activity, making it suitable for propane oxidative dehydrogenation reaction.
Patent Information
- Application Number
- CN202510852635.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-12-23
AI Technical Summary
Existing boron nitride nanosheets suffer from catalyst sintering due to excessive surface oxidation during propane oxidative dehydrogenation, leading to reduced stability and catalyst loss. Traditional methods have failed to effectively address the problem of preparing boron nitride fibers with high stability and high catalytic activity.
Boric acid and melamine were used as raw materials to prepare boron nitride fibers through recrystallization, vacuum drying, calcination and chemical activation treatment, which provided more BOx active sites and improved catalytic performance.
The prepared boron hydroxynitride fibers have a larger specific surface area and more defects, exhibiting excellent catalytic activity and stability, making them suitable for propane oxidative dehydrogenation reaction and improving the stability and efficiency of the catalyst.
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Figure CN121183459A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of material science, in particular to a preparation method of hydroxyl boron nitride fiber and its application in propane oxidative dehydrogenation. BACKGROUND
[0002] Boron nitride (BN) is often used as a catalyst carrier due to its chemical inertness. Recently, hexagonal boron nitride has attracted attention for its application in propane oxidative dehydrogenation. However, traditional boron nitride nanosheets have a problem of excessive surface oxidation, which leads to catalyst sintering, reduces the stability of the catalyst, and generates excessive boron oxide, resulting in catalyst loss. Therefore, it is particularly important to develop a boron nitride with high stability and high catalytic activity. Hydroxyl boron nitride fiber can provide more BOx active sites to promote the propane dehydrogenation reaction, which is of great significance. Currently, there is no report on the preparation method of hydroxyl boron nitride fiber. SUMMARY
[0003] To solve the above problems, the present application provides a preparation method of hydroxyl boron nitride fiber and its application in propane oxidative dehydrogenation, which has the characteristics of simple preparation and low cost.
[0004] The present application provides a preparation method of hydroxyl boron nitride fiber, which comprises the following steps:
[0005] (1) Dissolve boric acid and melamine in deionized water, recrystallize at 85℃, and vacuum dry to obtain a white precursor;
[0006] (2) Calcine the obtained precursor at high temperature to obtain boron nitride fiber;
[0007] (3) Chemically activate the obtained boron nitride fiber at room temperature to obtain hydroxyl boron nitride fiber.
[0008] Preferably, the molar ratio of boric acid to melamine is 2:1.
[0009] Preferably, the vacuum drying temperature is 60℃.
[0010] Preferably, the high-temperature calcination is carried out in nitrogen or ammonia at a temperature of 1000-1200℃, and the heating rate is 10℃ / min.
[0011] Preferably, the high-temperature calcination time is 3h.
[0012] Preferably, the room-temperature chemical activation treatment is: adding boron nitride fiber to a NaOH solution with a concentration of 1mol / L or a HNO3 solution with a concentration of 4mol / L at a temperature of 60℃, and then ultrasonic treatment and stirring.
[0013] Preferably, the ultrasonic treatment time is 30 min, and the stirring time is 4 h.
[0014] The application provides a hydroxyl boron nitride fiber prepared by the preparation method in any one of the technical solutions.
[0015] The application provides application of the hydroxyl boron nitride fiber prepared by the preparation method in any one of the technical solutions in propane oxidative dehydrogenation, in particular, application in catalytic propane oxidative dehydrogenation to prepare propylene.
[0016] The application has the following beneficial effects:
[0017] 1. The biological small molecule is used as a raw material to synthesize the hydroxyl boron nitride fiber, a new method is developed, the method has the advantages of wide raw material sources, low cost and simple preparation method, and can be used for large-scale synthesis, and the freezing drying step is simplified and high-temperature hydroxylation treatment is avoided.
[0018] 2. The hydroxyl boron nitride fiber obtained by the application has more defects and a larger specific surface area than the original boron nitride fiber.
[0019] 3. The hydroxyl boron nitride fiber obtained by the application has excellent performance in propane oxidative dehydrogenation. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description, and obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0021] Figure 1 It is a basic structure morphology comparison diagram of the original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber.
[0022] Figure 2 It is an X-ray powder diffraction (XRD) diagram of the original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber.
[0023] Figure 3 It is a Fourier infrared spectrum (FTIR) diagram of the original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber.
[0024] Figure 4 It is a nitrogen adsorption-desorption isotherm (BET) diagram of the original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber.
[0025] Figure 5Raman spectra of original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber.
[0026] Figure 6 Temperature and catalytic activity graph of original boron nitride fiber, BN-HNO3 fiber and BN-NaOH fiber;
[0027] Figure 7 Long-term stability test graph of synthesized BN-NaOH catalyst. DETAILED DESCRIPTION
[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0029] A preparation method of hydroxyl boron nitride fiber, comprising the following steps:
[0030] (1) Dissolving boric acid and melamine in deionized water, recrystallizing at 85℃, and vacuum drying to obtain white precursor;
[0031] (2) High-temperature calcining the obtained precursor to obtain boron nitride fiber;
[0032] (3) Chemically activating the obtained boron nitride fiber at room temperature to obtain hydroxyl boron nitride fiber.
[0033] Preferably, the molar ratio of the boric acid to the melamine is 2:1.
[0034] Preferably, the vacuum drying temperature is 60℃.
[0035] Preferably, the high-temperature calcining is carried out in nitrogen or ammonia at a temperature of 1000-1200℃, and the temperature rising rate is 10℃ / min.
[0036] Preferably, the high-temperature calcining time is 3h.
[0037] Preferably, the room-temperature chemical activation treatment is: adding the boron nitride fiber into a NaOH solution with a concentration of 1mol / L or a HNO3 solution with a concentration of 4mol / L at a temperature of 60℃, and then ultrasonic treating and stirring.
[0038] Preferably, the ultrasonic treating time is 30min, and the stirring time is 4h.
[0039] A hydroxyl boron nitride fiber is prepared by the preparation method in any one of the above technical solutions.
[0040] The application of the hydroxyl boron nitride fiber prepared by the preparation method in any of the above technical solutions in propane oxidative dehydrogenation, specifically in the preparation of propylene by catalytic propane oxidative dehydrogenation.
[0041] Example 1:
[0042] 1.24 g of boric acid and 1.26 g of melamine were dissolved in 100 mL of deionized water, recrystallized at 85°C, and white solids were obtained after 12 h. The precursor was dried in a vacuum drying oven at 60°C to obtain the precursor. The dried precursor was calcined at 1200°C under N2atmosphere at a heating rate of 10°C / min for 3 h to obtain boron nitride fibers. The boron nitride fibers were ultrasonically treated in 1 mol / L NaOH at 60°C for 30 min and then stirred for 4 h to obtain hydroxyl boron nitride fibers (BN-NaOH).
[0043] Example 2:
[0044] 1.24 g of boric acid and 1.26 g of melamine were dissolved in 100 mL of deionized water, recrystallized at 85°C, and white solids were obtained after 12 h. The precursor was dried in a vacuum drying oven at 60°C to obtain the precursor. The dried precursor was calcined at 1200°C under N2atmosphere at a heating rate of 10°C / min for 3 h to obtain boron nitride fibers. The boron nitride fibers were ultrasonically treated in 1 mol / L NaOH at 60°C for 30 min and then stirred for 4 h to obtain hydroxyl boron nitride fibers (BN-NaOH).
[0045] The basic structure and morphology of the original boron nitride fiber (BN), the BN-HNO3 fiber and the BN-NaOH fiber are compared as shown in Figure 1 , the crystal phase structure and functional group characterization are as shown in Figure 2 and Figure 3 , the specific surface area and defect characterization are as shown in Figure 4 and Figure 5 , and the propane oxidative dehydrogenation performance is as shown in Figure 6 and Figure 7 .
[0046] Result analysis:
[0047] Referring to Figure 1 , the basic structure and morphology of the original boron nitride fiber, the BN-HNO3 fiber and the BN-NaOH fiber under scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are compared, wherein a-c are the original boron nitride fiber, d-f are the BN-HNO3 fiber, and g-i are the BN-NaOH fiber. The hydroxyl boron nitride fibers (BN-HNO3 fiber and BN-NaOH fiber) synthesized in the above examples 1-2 are characterized by Figure 1The results show that the synthesized hydroxyl boron nitride fibers have a three-dimensional porous fiber morphology, and the surface morphology does not change significantly after chemical activation treatment. The BN-HNO3 surface formed by acid treatment has wrinkles, and the BN-NaOH surface formed by alkaline treatment has more obvious wrinkles and more defects.
[0048] Referring to Figure 2 and 3 , the hydroxyl boron nitride fibers (BN-HNO3 fibers and BN-NaOH fibers) synthesized in the above embodiment examples 1-2 are characterized by XRD, and it is found that the diffraction peaks are located at 26 o and 42.3 o , which are the phase of hexagonal boron nitride. The synthesized hydroxyl boron nitride fibers have a hexagonal graphite structure, and FTIR shows that the hydroxyl boron nitride fibers have a strong absorption peak at 3300 cm -1 -1, which is higher than that of the original boron nitride fibers, indicating that the synthesized hydroxyl boron nitride fibers have strong B-OH functional groups.
[0049] Referring to Figure 4 and 5 , the hydroxyl boron nitride fibers (BN-HNO3 fibers and BN-NaOH fibers) synthesized in the above embodiment examples 1-2 are characterized by XRD, and it is found that the diffraction peaks are located at 26 2 g -1 ) has a higher specific surface area than the original boron nitride fibers (176 m 2 g -1 ), such as BN-HNO3 with 311 m 2 g -1 . The Raman spectrum of the hydroxyl boron nitride fibers, especially BN-NaOH, has a wide half-peak width, indicating that the weak B-N force has more defects.
[0050] Referring to Figure 6 and 7 , the hydroxyl boron nitride fibers (BN-HNO3 fibers and BN-NaOH fibers) synthesized in the above embodiment examples 1-2 are tested for propane oxidative dehydrogenation reaction:
[0051] Propane oxidative dehydrogenation experiment: 200 mg of boron nitride material (20-40 mesh) was placed in the constant temperature zone of a 6 mm inner diameter quartz reaction tube, and the two ends were fixed with quartz wool. The reaction gas (propane 6 mL / min, oxygen 3 mL / min, helium 11 mL / min) was introduced, and the temperature was raised to 460-520°C for reaction, and gas chromatography was used for online analysis.
[0052] Compared with commercial boron nitride, BN-NaOH shows high conversion rate in the whole range, while the selectivity of propylene is similar for the three catalysts, which indicates that the synthesized hydroxyl boron nitride fiber has strong catalytic activity. At 520℃, the conversion rate of BN-NaOH reaches 23.2%, and the selectivity of the desired propylene and olefins reaches 75.2% and 90.1% respectively. Figure 7 It is shown that there is no fluctuation in the propane conversion and product selectivity on BN-NaOH during the reaction of 50h, which reflects the intended catalytic stability of the hydroxyl boron nitride fiber catalyst.
[0053] In conclusion, the hydroxyl boron nitride fiber prepared by the present application has obvious catalytic performance and catalytic stability, which means that it has great application prospect in actual industrial production. In addition, the above-mentioned examples are only used to illustrate a synthesis scheme and application example of the hydroxyl boron nitride fiber, and do not limit the embodiments and protection scope thereof. Based on the above description, one of ordinary skill in the art can make certain forms of changes or modifications. In the examples of the present application, the used examples do not need and cannot be exhausted one by one. Therefore, the obvious changes and modifications derived from the present application are still within the protection scope of the present application.
Claims
1. A method for preparing boron hydroxynitride fibers, characterized in that, Includes the following steps: (1) Boric acid and melamine were dissolved in deionized water, recrystallized at 85°C, and dried under vacuum to obtain a white precursor; (2) The obtained precursor was calcined at high temperature to obtain boron nitride fiber; (3) The obtained boron nitride fibers were chemically activated at room temperature to obtain hydroxy boron nitride fibers.
2. The method for preparing boron hydroxynitride fibers as described in claim 1, characterized in that, The molar ratio of boric acid to melamine is 2:
1.
3. The method for preparing boron nitride fibers as described in claim 1, characterized in that, The vacuum drying temperature is 60°C.
4. The method for preparing boron nitride fiber as described in claim 1, characterized in that, The high-temperature calcination is carried out in nitrogen or ammonia gas at a temperature of 1000-1200℃, with a heating rate of 10℃ / min.
5. The method for preparing boron hydroxynitride fibers as described in claim 4, characterized in that, The high-temperature calcination time is 3 hours.
6. The method for preparing boron hydroxynitride fibers as described in claim 1, characterized in that, The room temperature chemical activation treatment is as follows: boron nitride fibers are added to a 1 mol / L NaOH solution or a 4 mol / L HNO3 solution at 60°C and ultrasonically treated, followed by stirring.
7. The method for preparing boron hydroxynitride fibers as described in claim 6, characterized in that, The ultrasonic treatment time was 30 minutes, and the stirring time was 4 hours.
8. A boron nitride fiber, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.
9. The application of boron hydroxynitride fibers prepared by the preparation method according to any one of claims 1-7 in the catalytic oxidative dehydrogenation of propane to propylene.