A method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods

Abstract

The invention provides a method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods, belonging to the technical field of nanomaterial preparation. In the method, FeCl3·6H2O and urea are heated in a water bath to obtain β-FeOOH nanorods, which are then dried and ground. The β-FeOOH nanorods are then mixed with urea and placed in a crucible. The crucible is placed in a programmable temperature-controlled furnace, heated and calcined, and naturally cooled after heat treatment to obtain magnetic Fe3O4 / α-Fe2O3 nanorods. The magnetic Fe3O4 / α-Fe2O3 nanorods have uniform structure, controllable size, and high yield. The method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods has the advantages of simple operation, short preparation cycle, and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material preparation, and particularly relates to a method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods. Background Art

[0002] Nanomaterials hold broad application prospects in chemistry, mechanics, electronics, medicine, and other fields. Nanomaterials include nanoparticles, nanosheets, nanorods, and nanotubes. Magnetic nanomaterials, in particular, are being extensively studied for their unique properties across a wide range of applications. Magnetic nanomaterials are gaining increasing attention in the biomedical field. Among the diverse types of magnetic nanomaterials, magnetic α-Fe2O3 nanomaterials are particularly prominent. Due to their excellent biocompatibility and biodegradability, α-Fe2O3 nanomaterials are gaining increasing prominence in biomedicine. However, their low magnetic properties result in poor targeting. While Fe3O4 nanomaterials offer advantages such as low toxicity, good biocompatibility, and high saturation magnetization, their high magnetic properties lead to aggregation. Therefore, combining Fe3O4 with α-Fe2O3 as drug delivery vehicles is being explored to mitigate the shortcomings of both Fe3O4 and α-Fe2O3.

[0003] Magnetic α-Fe2O3 nanomaterials can be reduced to Fe3O4 upon addition of a reducing agent. Under controlled conditions, magnetic Fe3O4 / α-Fe2O3 nanomaterials can be directly formed. In the prior art, FeSO4 and hexamethylenetetramine are dissolved in deionized water, stirred for 2 hours, and then the solution is hydrothermally reacted at 180°C for 24 hours. After cooling to room temperature, the mixture is washed with anhydrous ethanol and dried to produce Fe3O4 / α-Fe2O3 nanorods. This preparation method has the disadvantages of high risk and a long preparation time. Therefore, a method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods that is simple to operate and has a short preparation time is needed. Summary of the Invention

[0004] To address some shortcomings in the prior art, the present invention provides a method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods. In the method, FeCl3·6H2O and urea are heated in a water bath to produce β-FeOOH nanorods. After drying and grinding, the β-FeOOH nanorods are mixed with urea and placed in a crucible. The crucible is then placed in a programmable temperature-controlled furnace and calcined at elevated temperatures. After heat treatment, the mixture is naturally cooled to produce magnetic Fe3O4 / α-Fe2O3 nanorods. The magnetic Fe3O4 / α-Fe2O3 nanorods exhibit uniform structure, controllable size, and high yield. The method also offers advantages such as simple operation and a short preparation cycle.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods, comprising the following steps:

[0007] (1) FeCl3·6H2O and urea were heated in a water bath, and the product was dried and ground to obtain β-FeOOH nanorods;

[0008] (2) The β-FeOOH nanorods obtained in step (1) are mixed with urea and calcined at elevated temperature to obtain magnetic Fe3O4 / α-Fe2O3 nanorods.

[0009] Preferably, in step (1), the water bath heating temperature is 75-95° C., and the water bath time is 4 h.

[0010] Preferably, in step (1), the molar ratio of FeCl3·6H2O to urea is 1:1-1:4.

[0011] Preferably, in step (2), the mass ratio of the β-FeOOH nanorods to urea is 1:2-1:16.

[0012] Preferably, in step (2), the calcination temperature is 400°C.

[0013] Preferably, the calcination is carried out by heating the temperature to 400° C. at a heating rate of 2 to 12° C. / min.

[0014] Preferably, in step (2), the calcination time is 1 to 6 hours.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention, for the first time, uses urea to reduce β-FeOOH nanorods to produce magnetic Fe₃O₄ / α-Fe₂O₃ nanorods. The resulting magnetic Fe₃O₄ / α-Fe₂O₃ nanorods exhibit advantages such as uniform structure, controllable size, and high yield. The invention utilizes FeCl₃·6H₂O and urea in a water bath to produce the β-FeOOH nanorods, followed by drying and grinding. The ground β-FeOOH nanorods are then mixed with urea and calcined. This simple process omits many complex preparation processes. The dissolution, water bath heating, drying, and calcination process takes no more than 20 hours, significantly reducing preparation time.

[0017] In this method, urea is used as a reducing agent and co-calcined with β-FeOOH nanorods. The saturation magnetization of the magnetic Fe₃O₄ / α-Fe₂O₃ nanorods is controlled by varying the mass ratio of urea to β-FeOOH nanorods and the calcination time. This method is safer than the hydrothermal method. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the scanning electron microscopy image of magnetic Fe3O4 / α-Fe2O3 nanorods;

[0019] Figure 2 is the hysteresis loop diagram of magnetic Fe3O4 / α-Fe2O3 nanorods;

[0020] Figure 3 is the X-ray diffraction pattern of magnetic Fe3O4 / α-Fe2O3 nanorods;

[0021] Figure 4 This is the X-ray photoelectron spectrum of magnetic Fe3O4 / α-Fe2O3 nanorods. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0023] Example 1:

[0024] (1) 10.81 g of FeCl3·6H2O and 4.81 g of urea were added to 50 mL of distilled water and dissolved under magnetic stirring for 0.5 h. The homogeneous solution was then transferred to a round-bottom flask and magnetically stirred at 75 °C for 4 h. The suspension was then centrifuged, washed with distilled water, dried, and then ground to obtain β-FeOOH.

[0025] (2) 0.1 g of β-FeOOH and 0.6 g of urea were mixed and placed in a crucible. The crucible was placed in a programmable temperature-controlled furnace and calcined at 400 °C for 2 h at a heating rate of 3 °C / min. After heat treatment, the mixture was naturally cooled to obtain magnetic Fe3O4 / α-Fe2O3 nanorods.

[0026] Figure 1The scanning electron microscope image of the magnetic Fe3O4 / α-Fe2O3 nanorod constructed under the conditions described in this embodiment shows a length of 284.94nm and a diameter of 65.81nm. The saturation magnetization of the magnetic Fe3O4 / α-Fe2O3 nanorod has a certain relationship with its length and diameter. When the length and diameter increase, when the β-FeOOH nanorod is calcined with urea, the content of Fe3O4 and α-Fe2O3 will change to some extent, thereby affecting the size of the saturation magnetization. When the length is 284.94nm and the diameter is 65.81nm, the magnetic properties of the Fe3O4 / α-Fe2O3 nanorod are optimal and the diameter is minimum, making it more suitable for the research of later drug delivery system targeted therapy for cancer cells.

[0027] Figure 2 This is the hysteresis loop diagram of the magnetic Fe3O4 / α-Fe2O3 nanorods constructed under the conditions described in this example, and the saturation magnetization intensity is 42.03emu / g.

[0028] Figure 3 This is the X-ray diffraction pattern of the magnetic Fe3O4 / α-Fe2O3 nanorods constructed under the conditions described in this example. Its standard PDF cards are No.72-0469 and No.88-0315, which proves the successful preparation of the magnetic Fe3O4 / α-Fe2O3 nanorods.

[0029] Figure 4 This is the X-ray photoelectron spectrum of the magnetic Fe3O4 / α-Fe2O3 nanorods constructed under the conditions described in this example, which proves the existence of both Fe3O4 and α-Fe2O3, indicating the successful preparation of magnetic Fe3O4 / α-Fe2O3 nanorods.

[0030] Example 2:

[0031] (1) 10.81 g of FeCl3·6H2O and 2.40 g of urea were added to 50 mL of distilled water and dissolved under magnetic stirring for 1 h. The homogeneous solution was then transferred to a round-bottom flask and magnetically stirred at 85 °C for 4 h. The suspension was then centrifuged, washed with distilled water, dried, and then ground to obtain β-FeOOH nanorods.

[0032] (2) 0.2 g of β-FeOOH nanorods were mixed with 0.8 g of urea and placed in a crucible. The crucible was placed in a programmable temperature-controlled furnace and calcined at 400 °C for 1 h at a heating rate of 5 °C / min. After heat treatment, the mixture was naturally cooled to obtain magnetic Fe3O4 / α-Fe2O3 nanorods.

[0033] Example 3:

[0034] (1) 8.11 g of FeCl3·6H2O and 3.60 g of urea were added to 50 mL of distilled water and dissolved under magnetic stirring for 2 h. The homogeneous solution was then transferred to a round-bottom flask and magnetically stirred at 85 °C for 4 h. The suspension was then centrifuged, washed with distilled water, dried, and then ground to obtain β-FeOOH nanorods.

[0035] (2) 0.1 g of β-FeOOH nanorods were mixed with 0.8 g of urea and placed in a crucible. The crucible was placed in a programmable temperature-controlled furnace and calcined at 400 °C for 3 h at a heating rate of 7 °C / min. After heat treatment, the mixture was naturally cooled to obtain magnetic Fe3O4 / α-Fe2O3 nanorods.

[0036] Example 4:

[0037] (1) 5.41 g of FeCl3·6H2O and 2.40 g of urea were added to 50 mL of distilled water and dissolved under magnetic stirring for 0.5 h. The homogeneous solution was then transferred to a round-bottom flask and magnetically stirred at 95 °C for 4 h. The suspension was then centrifuged, washed with distilled water, dried, and then ground to obtain β-FeOOH nanorods.

[0038] (2) 0.1 g of β-FeOOH nanorods and 0.4 g of urea were mixed and placed in a crucible. The crucible was placed in a programmable temperature-controlled furnace and calcined at 400 °C for 2 h at a heating rate of 10 °C / min. After heat treatment, the mixture was naturally cooled to obtain magnetic Fe3O4 / α-Fe2O3 nanorods.

[0039] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods, characterized in that: The construction method comprises the following steps: (1) FeCl3∙6H2O and urea were heated in a water bath, and the product was dried and ground to obtain β-FeOOH nanorods; (2) The β-FeOOH nanorods obtained in step (1) are mixed with urea and calcined at a high temperature to obtain magnetic Fe3O4 / α-Fe2O3 nanorods; in step (1), the water bath heating temperature is 75°C and the water bath time is 4 h; the molar ratio of FeCl3∙6H2O to urea is 1:2; in step (2), the mass ratio of the β-FeOOH nanorods to urea is 1:2-1:

16.

2. The method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods according to claim 1, wherein: In step (2), the calcination temperature is 400°C.

3. The method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods according to claim 2, characterized in that: The calcination is carried out by heating the temperature to 400° C. at a heating rate of 2-12° C. / min.

4. The method for constructing magnetic Fe3O4 / α-Fe2O3 nanorods according to claim 1, wherein: In step (2), the calcination time is 1 to 6 hours.

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