Amorphous alumina nanowire material and preparation method thereof

Abstract

The invention discloses an amorphous alumina nanowire material and a preparation method thereof. The preparation method comprises the following steps: (1) sealing a mixture of ZrO2 powder and AlI3 powder in a reaction tube, and calcining to obtain a precursor aluminum oxygen iodine nanowire; and (2) calcining the precursor aluminum oxygen iodine nanowire to prepare the amorphous aluminum oxide nanowire material. The preparation method is simple, a reaction source is environment-friendly, industrial production is easy, and the prepared one-dimensional amorphous aluminum oxide nanowire material is uniform in shape, high in length-diameter ratio and excellent in mechanical property.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of amorphous aluminum oxide nanowire materials and preparation method thereof. BACKGROUND

[0002] Aluminum oxide nanomaterials are widely used in catalysis, composite materials and other fields due to their high specific surface area and excellent stability. Among them, one-dimensional nanowire structures are of great interest due to their anisotropy and other characteristics. Currently, the preparation techniques for aluminum oxide nanowires mainly focus on crystalline materials, such as synthesis by high-temperature vapor deposition, hydrothermal method combined with high-temperature calcination, or template method. These methods have significant drawbacks: first, they usually require high temperature (>1000℃) or high pressure environment, which is energy-consuming and requires harsh equipment; second, the process is complex and often involves toxic precursors or difficult-to-remove catalysts, resulting in low product purity; third, the precursor obtained by hydrothermal method needs to be treated by high-temperature crystallization, which easily leads to sintering, agglomeration and morphology damage of nanowires, resulting in a significant decrease in specific surface area. Compared with crystalline materials, amorphous aluminum oxide nanowires have long-range disorder structure, showing unique advantages such as uniform structure, rich defects, and high surface energy, and have greater potential in catalysis and composite material interface bonding. However, existing technologies are difficult to directly and efficiently prepare high-purity and regular-shaped amorphous aluminum oxide nanowires, and there are common problems such as complex process, harsh conditions, and uncontrollable crystallization, which seriously restrict their application and development. Therefore, there is an urgent need to develop a new method for preparing high-purity amorphous aluminum oxide nanowires under mild conditions and simple process. SUMMARY

[0003] The technical problem solved by the present application is to overcome the defects of complex preparation method and uncontrollable crystallization of amorphous aluminum oxide nanowires in existing technologies, and to provide an amorphous aluminum oxide nanowire material and a preparation method thereof. The preparation method of the present application is simple, the reaction source is friendly to the environment, and it is easy to industrialize production. The one-dimensional amorphous aluminum oxide nanowire material prepared has uniform morphology and high aspect ratio, and has excellent mechanical properties.

[0004] The present application successfully prepares amorphous aluminum oxide nanowires with nanowire morphology by solid-phase reaction of oxides and iodides for the first time. First, ZrO2 particles and AlI3 particles are reacted by solid-phase synthesis to prepare aluminum-oxygen-iodine nanowire precursor. Further air annealing of the aluminum-oxygen-iodine nanowire converts it into amorphous aluminum oxide nanowire.

[0005] The present application solves the above technical problems by the following technical solutions:

[0006] The present application provides a preparation method of amorphous aluminum oxide nanowire material, which comprises the following steps:

[0007] (1) calcining a mixture of ZrO2 powder and AlI3 powder in a reaction tube to obtain a precursor aluminum oxy-iodine nanowire;

[0008] (2) calcining the precursor aluminum oxy-iodine nanowire to obtain the amorphous aluminum oxide nanowire material.

[0009] In step (1), the molar ratio of the ZrO2 powder to the AlI3 powder is preferably no more than 1, more preferably 0.7-1, for example 0.75, 0.8 or 0.9. When the amount of ZrO2 is too much, the reactants cannot react completely, thus the aluminum oxide nanowire cannot be obtained.

[0010] In step (1), the mixture of ZrO2 powder and AlI3 powder can be prepared by conventional methods in the art, for example by grinding ZrO2 and AlI3 uniformly. The grinding is generally performed in an argon atmosphere.

[0011] In step (1), the reaction tube is preferably a quartz tube.

[0012] In step (1), the calcining is generally performed in a vacuum environment; before the reaction tube is sealed, the reaction tube is generally vacuumed. After the vacuuming, the vacuum degree in the reaction tube is preferably less than or equal to 10 -3 Pa. The sealing method can be conventional in the art, for example by sealing the tube with a quartz column to achieve sealing.

[0013] In step (1), the calcining can be performed in a conventional sintering furnace (for example a single-temperature-zone tube furnace) or a double-temperature-zone tube furnace.

[0014] In step (1), the calcining temperature can be 300-500℃, for example 350℃, 375℃, 400℃ or 450℃; the calcining time can be 48-72h, for example 48h, 50h, 60h, 65h or 70h.

[0015] In step (1), when the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is preferably 350-450°C, for example 380°C, 400°C, 425°C, 430°C or 450°C; the low-temperature end temperature of the double-temperature-zone tube furnace can be 350-450°C, for example 350°C, 375°C or 400°C; the time for the calcination is preferably 48-80 h, for example 48 h, 60 h, 70 h or 72 h; the rate of temperature rise to the temperature for the calcination can be 60-300°C / h, for example 100°C / h, 120°C / h or 150°C / h. During the calcination, the reaction tube is generally placed at the high-temperature end temperature zone with the mixed powder at one end, and is kept at the preset temperature for a preset time. According to the convention in the art, after the calcination is completed, natural cooling to room temperature is generally required. According to the convention in the art, the high-temperature end zone and the low-temperature end zone of the double-temperature-zone tube furnace can each be provided with a calcination temperature and a temperature rise rate, and the two zones can perform the calcination simultaneously with the same holding time. After the calcination is completed, the precursor aluminum oxyiodide nanowires are generally grown on the inner wall of the reaction tube.

[0016] In a specific embodiment, in step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 450°C, the low-temperature end temperature of the double-temperature-zone tube furnace is 400°C, and the time for the calcination is 60 h.

[0017] In a specific embodiment, in step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 425°C, the low-temperature end temperature of the double-temperature-zone tube furnace is 375°C, and the time for the calcination is 60 h.

[0018] In a specific embodiment, in step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 450°C, the low-temperature end temperature of the double-temperature-zone tube furnace is 400°C, and the time for the calcination is 70 h.

[0019] In a specific embodiment, in step (1), the calcination is performed in a single-temperature-zone tube furnace, the temperature for the calcination is 400°C, and the time for the calcination is 60 h.

[0020] In step (1), the diameter of the precursor aluminum oxyiodide nanowires can be 100-300 nm, for example 150 nm, 200 nm or 250 nm; the length of the precursor aluminum oxyiodide nanowires can be 10-150 μm, for example 50 μm, 80 μm, 100 μm or 120 μm.

[0021] In step (2), the calcination is generally performed in an air atmosphere; the calcination can be performed in a muffle furnace or a tube furnace. The temperature of the calcination can be 150-800°C, such as 200°C, 300°C, 350°C, 400°C, 450°C, 500°C or 600°C; the time of the calcination can be 0.5-12h, such as 2h, 3h, 4h or 6h; the rate of heating to the temperature of the calcination can be 60-300°C / h, such as 100°C / h, 120°C / h or 150°C / h. After the calcination, natural cooling to room temperature is generally required.

[0022] The present application also provides an amorphous aluminum oxide nanowire material prepared by the preparation method as described above.

[0023] In the present application, the diameter of the amorphous aluminum oxide nanowire can be 50-600 nm, such as 100 nm, 150 nm, 200 nm, 250 nm, 300 nm or 400 nm; the length of the amorphous aluminum oxide nanowire can be 10-200 μm, such as 30 μm, 50 μm, 60 μm, 80 μm, 90 μm, 100 μm, 120 μm, 150 μm or 180 μm.

[0024] On the basis of common knowledge in the art, the above-mentioned preferred conditions can be combined in any manner, thereby obtaining various preferred examples of the present application.

[0025] The reagents and raw materials used in the present application are commercially available.

[0026] The positive progress effect of the present application is that:

[0027] The present application successfully prepares amorphous aluminum oxide nanowires with nanowire morphology for the first time by solid-phase reaction of oxides and iodides, and the preparation method provided by the present application has the advantages of simple steps, short growth period and high success rate, and the obtained amorphous aluminum oxide nanowires have the advantages of large number, high length-diameter ratio and uniform morphology. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The structure of the quartz tube and the placement position of the raw materials in the quartz tube in the examples of the present application;

[0029] Figure 2 The optical photograph of the aluminum-oxygen-iodine nanowires prepared in Example 1;

[0030] Figure 3 The scanning electron microscope image of the aluminum-oxygen-iodine nanowires prepared in Example 1;

[0031] Figure 4 The XRD pattern of the amorphous aluminum oxide nanowires prepared in Example 1;

[0032] Figure 5Raman spectrum of amorphous alumina nanowires prepared in Example 1.

[0033] Figure 6 Scanning electron microscope image of amorphous alumina nanowires prepared in Example 1.

[0034] Figure 7 XPS spectrum of aluminum oxy-iodine nanowires prepared in Example 1.

[0035] Figure 8 XPS spectrum of amorphous alumina nanowires prepared in Example 1.

[0036] Figure 9 Optical photograph of amorphous alumina nanowires prepared in Example 1.

[0037] Figure 10 Thermogravimetric analysis spectrum of aluminum oxy-iodine nanowires prepared in Example 1.

[0038] Figure 11 Scanning electron microscope image of the device for tensile test described in Example 1.

[0039] Figure 12 Mechanical property spectrum of amorphous alumina nanowires prepared in Example 1.

[0040] Figure 13 Scanning electron microscope image of amorphous alumina nanowires prepared in Example 2. DETAILED DESCRIPTION

[0041] The present application is further illustrated by the following examples without thereby limiting the present application to the examples described. The experimental methods in the following examples, for which no specific conditions are indicated, are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0042] Example 1

[0043] (1) High-purity Zr02powder (purity 99.9%) and high-purity AlI3powder (purity 99.5%) were mixed in a molar ratio of 3:4, ground and mixed thoroughly to obtain a mixed powder, and the mixed powder was placed in a quartz tube. The quartz tube containing the mixed powder was evacuated and sealed, and placed in a double-temperature-zone tube furnace. The high-temperature end was heated to 450°C at a rate of 120°C / h, and the low-temperature end was heated to 400°C at a rate of 120°C / h. After 60 hours of heat preservation, the heating was stopped, and the quartz tube was naturally cooled to room temperature. Aluminum oxy-iodine nanowires were obtained on the inner wall of the quartz tube.

[0044] (2) The aluminum oxy-iodine nanowires were placed in a muffle furnace and heated to 400°C at a rate of 120°C / h and heat preserved for 3 hours. Then the heating was stopped, and the muffle furnace was naturally cooled to room temperature to obtain good quality amorphous alumina nanowires.

[0045] Example 2

[0046] (1) High purity Zr02 powder (purity 99.9%) and high purity AlI3 powder (purity 99.5%) were mixed in a molar ratio of 3:4, ground and mixed thoroughly to obtain a mixed powder, and the mixed powder was placed in a quartz tube. The quartz tube containing the mixed powder was vacuumed and sealed, and placed in a double-temperature-zone tube furnace. The high-temperature end was heated to 425°C at a rate of 120°C / h, and the low-temperature end was heated to 375°C at a rate of 120°C / h. After 60 hours of heat preservation, the heating was stopped, and the quartz tube was naturally cooled to room temperature. Aluminum oxy-iodine nanowires were obtained on the inner wall of the quartz tube.

[0047] (2) The aluminum oxy-iodine nanowires were placed in a muffle furnace and heated to 400°C at a rate of 120°C / h and kept for 3 hours. Then the heating was stopped, and the muffle furnace was naturally cooled to room temperature. Good quality amorphous aluminum oxide nanowires were obtained.

[0048] Example 3

[0049] (1) High purity Zr02 powder (purity 99.9%) and high purity AlI3 powder (purity 99.5%) were mixed in a molar ratio of 3:4, ground and mixed thoroughly to obtain a mixed powder, and the mixed powder was placed in a quartz tube. The quartz tube containing the mixed powder was vacuumed and sealed, and placed in a double-temperature-zone tube furnace. The high-temperature end was heated to 450°C at a rate of 120°C / h, and the low-temperature end was heated to 400°C at a rate of 120°C / h. After 70 hours of heat preservation, the heating was stopped, and the quartz tube was naturally cooled to room temperature. Aluminum oxy-iodine nanowires were obtained on the inner wall of the quartz tube.

[0050] (2) The aluminum oxy-iodine nanowires were placed in a muffle furnace and heated to 400°C at a rate of 120°C / h and kept for 3 hours. Then the heating was stopped, and the muffle furnace was naturally cooled to room temperature. Good quality amorphous aluminum oxide nanowires were obtained.

[0051] Example 4

[0052] (1) High purity Zr02 powder (purity 99.9%) and high purity AlI3 powder (purity 99.5%) were mixed in a molar ratio of 3:4, ground and mixed thoroughly to obtain a mixed powder, and the mixed powder was placed in a quartz tube. The quartz tube containing the mixed powder was vacuumed and sealed, and placed in a double-temperature-zone tube furnace. The high-temperature end was heated to 425°C at a rate of 120°C / h, and the low-temperature end was heated to 375°C at a rate of 120°C / h. After 60 hours of heat preservation, the heating was stopped, and the quartz tube was naturally cooled to room temperature. Aluminum oxy-iodine nanowires were obtained on the inner wall of the quartz tube.

[0053] (2) The aluminum oxide nanowires were placed in a muffle furnace and heated to 400°C at a rate of 120°C / h and held for 3 hours. Then the heating was stopped and the muffle furnace was allowed to cool naturally to room temperature to obtain high-quality amorphous aluminum oxide nanowires.

[0054] Effect Example

[0055] (1) Morphological and structural characteristics

[0056] Figure 1 This illustrates the structure of the quartz tube in this embodiment of the invention, and the placement of the reactants within the quartz tube during the preparation of amorphous alumina nanowires.

[0057] A physical image of the aluminum-oxygen-iodine nanowires prepared in Example 1 is shown below. Figure 2 As shown, it appears as a regularly arranged array of white nanowires attached to the inner wall of a quartz tube; its SEM image and EDS results are as follows. Figure 3 As shown in the figure, the aluminum-oxygen-iodine nanowires are approximately 100 μm long and 200 nm in diameter. Surface scanning of this region reveals that the nanowires contain Al, O, and I elements. Semi-quantitative analysis indicates that the atomic ratio of Al to O is approximately 1:2. The XPS results are shown below. Figure 7 As shown, the Al 2p spectrum reveals a main peak corresponding to the Al-O bond at 74.8 eV for the prepared aluminum-oxygen-iodine nanowires.

[0058] The XRD pattern of the amorphous alumina nanowires prepared in Example 1 is shown below. Figure 4 As shown, the prepared alumina nanowires are amorphous; their Raman diagram is as follows. Figure 5 As shown, the absence of characteristic peaks in the signal confirms that the alumina nanowires are amorphous; their SEM images and EDS results are as follows. Figure 6 As shown in the figure, the alumina nanowires are approximately 100 μm long and 300 nm in diameter. Surface scanning of this region reveals that the nanowires mainly contain Al and O elements. Semi-quantitative analysis indicates that the atomic ratio of Al to O is approximately 2:3. Its XPS values ​​are as follows: Figure 8 As shown in the Al 2p spectrum, the prepared amorphous alumina nanowire material exhibits a main peak corresponding to the Al-O bond at 74.6 eV; its optical image is shown below. Figure 9 As shown, it appears as white linear clusters.

[0059] The thermogravimetric curve of the aluminum-oxygen-iodine nanowires prepared in Example 1 is shown in Figure 1. Figure 10 As shown in the figure, the mass of the aluminum-oxygen-iodine nanowires gradually decreases during heating and remains stable after 370℃, reflecting the gradual removal of iodine during heating. The SEM images and EDS results of the amorphous alumina nanowires prepared in Example 2 are shown below.Figure 13 As shown in the figure, the length of the alumina nanowire is about 100 μm and the diameter is about 300 nm. The area is scanned and the result shows that the nanowire mainly contains Al and O elements. The semi-quantitative analysis shows that the atomic ratio of Al and O is about 2:3. In addition, the yield of the amorphous alumina nanowire prepared in Example 1 is calculated according to the ratio of the actual yield to the theoretical yield, and the yield result is shown in Table 1. The yield of the amorphous alumina nanowire is more than 90%, indicating that the preparation strategy has a high success rate.

[0060] Table 1

[0061]

[0062] (2) Mechanical property test

[0063] The mechanical properties of the final product prepared in each of the above examples are evaluated by using Picoindenter 85 nanoindenter (Pi-85) integrated in Quanta 250 FEG scanning electron microscope and PTP device for in-situ tensile test.

[0064] The final product material prepared in Example 1 is fixed to the PTP sample area by FIB technology. Its average diameter and initial length are measured according to the scanning electron microscope observation. The cross-sectional area of each cylindrical amorphous alumina nanowire is calculated according to its diameter, and the initial length is defined as the distance between the two fixed points. Before testing, the flat probe is positioned to contact the semicircular end of the amorphous alumina nanowire mounted on the PTP device. The tensile test is carried out at a rate of 10 nm / s in displacement control mode until fracture occurs. The force and displacement data are dynamically recorded, and the resulting force-displacement curve contains the contributions of the PTP device and the amorphous alumina nanowire sample. Therefore, the inherent contribution of the PTP device is subtracted to determine the force applied to the amorphous alumina nanowire sample, and the test results and Figure 11 and Figure 12 as shown:

[0065] Figure 11 The scanning electron microscope of the mechanical testing device of Figure 12 The test results of

[0066] ​Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that the present application is only illustrated by way of example, and the scope of protection of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to the embodiments without departing from the principles and essence of the present application, and such changes and modifications fall within the scope of protection of the present application.

Claims

1. A method of producing an amorphous aluminum oxide nanowire material, characterized by, It comprises the following steps: (1) calcining a mixture of ZrO2 powder and AlI3 powder in a reaction tube to obtain a precursor aluminum oxyiodide nanowire; (2) calcining the precursor aluminum oxyiodide nanowire to obtain the amorphous aluminum oxide nanowire material.

2. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), the molar ratio of the ZrO2 powder to the AlI3 powder is not more than 1, preferably 0.7-1, for example 0.75, 0.8 or 0.

9.

3. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), the reaction tube is a quartz tube.

4. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), the reaction tube is evacuated before being sealed.

5. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), the temperature of the calcination is 300-500℃, for example 350℃, 375℃, 400℃ or 450℃; And / or, the time of the calcination is 48-72h, for example 48h, 50h, 60h, 65h or 70h.

6. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), when the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 350-450℃, for example 380℃, 400℃, 425℃, 430℃ or 450℃; And / or, in step (1), when the calcination is performed in a double-temperature-zone tube furnace, the low-temperature end temperature of the double-temperature-zone tube furnace is 350-450℃, for example 350℃, 375℃ or 400℃; And / or, in step (1), the time of the calcination is 48-80h, for example 48h, 60h, 70h or 72h.

7. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 450℃, the low-temperature end temperature of the double-temperature-zone tube furnace is 400℃, and the time of the calcination is 60h; Or, in step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 425℃, the low-temperature end temperature of the double-temperature-zone tube furnace is 375℃, and the time of the calcination is 60h; Or, in step (1), the calcination is performed in a double-temperature-zone tube furnace, the high-temperature end temperature of the double-temperature-zone tube furnace is 450℃, the low-temperature end temperature of the double-temperature-zone tube furnace is 400℃, and the time of the calcination is 70h; Or, in step (1), the calcination is performed in a single-temperature-zone tube furnace, the temperature of the calcination is 400℃, and the time of the calcination is 60h.

8. The method for preparing amorphous alumina nanowire material as described in claim 1, characterized in that, In step (2), the calcination is performed in an air atmosphere; And / or, the temperature of the calcination is 150-800℃, for example 200℃, 300℃, 350℃, 400℃, 450℃, 500℃ or 600℃; And / or, the time of the calcination is 0.5-12h, for example 2h, 3h, 4h or 6h.

9. An amorphous aluminum oxide nanowire material prepared by the method of any one of claims 1-8.

10. The amorphous aluminum oxide nanowire material of claim 9, wherein, The diameter of the amorphous aluminum oxide nanowire is 50-600 nm; And / or, the length of the amorphous aluminum oxide nanowire is 10-200 μm.

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