Method for preparing PtFe alloy nanowire with intermetallic compound shell at low temperature
Through low-temperature vacuum heat treatment technology, the problem of difficulty in maintaining the morphology and particle size of platinum-based nanomaterials at high temperatures is solved, forming an intermetallic compound shell, improving catalytic activity and stability, and suitable for large-scale production.
Patent Information
- Application Number
- CN202411367459.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-01-03
AI Technical Summary
It is difficult for existing platinum-based nanomaterials to maintain their original morphology and particle size during high-temperature heat treatment, resulting in a decrease in catalytic performance and agglomeration problems.
Using low-temperature vacuum heat treatment method, the PtFe alloy nanowires are loaded on carbon material or conductive metal oxide support, and the orderly reconstruction of the surface atoms on the nanomaterial surface through gentle heat treatment conditions to form an intermetallic compound shell to avoid agglomeration and maintain nanomaterials. original morphology and particle size.
It improves the catalytic activity and stability of platinum-based nanomaterials, inhibits the corrosion and dissolution of transition metals, and is suitable for large-scale production without requiring post-treatment.
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Figure CN119243063A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of preparation of precious metal nanomaterials, and relates to a method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature. Background Art
[0002] The crystal structure of the platinum-based nanomaterials usually prepared is mainly a face-centered cubic structure. Since the lattice positions occupied by platinum and alloyed transition metals are disordered, they face serious problems of corrosion and precipitation of transition metal elements during the electrocatalytic reaction, which seriously restricts the stability during the catalytic process. The ordered structure of platinum-based intermetallic compounds shows excellent catalytic activity and stability compared to the disordered face-centered cubic structure. However, the current method for preparing platinum-based intermetallic compounds is still mainly limited to heat treatment under high temperature conditions, making it difficult to maintain the original morphology of the nanomaterial during the heat treatment process. While obtaining the structural advantages of the intermetallic compound, it will also cause the sacrifice of the high catalytic performance crystal surface.
[0003] Chinese patent application CN101976737A discloses a method for preparing platinum-iron intermetallic compounds by high-temperature heat treatment of disordered alloys in a reducing atmosphere. Although the method has simple steps and the prepared intermetallic compounds have a high degree of order, the nanomaterials undergo significant agglomeration during the heat treatment process, and the morphology and particle size are significantly changed. Chinese patent application CN118099447A discloses a method for preparing carbon-supported platinum-based intermetallic compounds by high-temperature heat treatment in an inert atmosphere. Although the method improves the oxygen reduction catalytic performance by ordering the structure of platinum-based nanomaterials, the nanomaterials still undergo significant agglomeration during the heat treatment process. Chinese patent application CN116417622A discloses a method for preparing carbon-supported platinum-based intermetallic compound nanomaterials using Joule thermal shock. Although the prepared nanomaterials have good uniformity and no agglomeration occurs, the crystal plane of the nanomaterial cannot be regulated, the batch stability needs to be verified, and it is difficult to mass produce.
[0004] In the application scenarios of platinum-based nanomaterials, factors such as composition, morphology, structure, particle size, and dispersibility determine their performance and stability. Therefore, it is particularly important to develop a general preparation method that can achieve ordered phase transition of platinum-based nanomaterials without agglomeration and without changing the original morphology and particle size of the nanomaterials. Summary of the invention
[0005] The purpose of the present invention is to provide a method for preparing platinum-based nanomaterials with an intermetallic compound shell at low temperature, which is used to overcome the defects of the existing high-temperature heat treatment method for preparing platinum-based intermetallic compounds, which makes it difficult to maintain the original morphology and particle size of the nanomaterial during the heat treatment process, while sacrificing the defects of the crystal surface with high catalytic performance while obtaining the structural advantages of the intermetallic compound.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] A method for preparing a PtFe alloy nanowire having an intermetallic compound shell comprises: loading the PtFe alloy nanowire on a carrier and subjecting the carrier to vacuum heat treatment at 350-400°C;
[0008] Among them, the present invention has no restrictions on the composition, morphology, and preparation method of the PtFe alloy nanowires; the morphology of the PtFe alloy nanowires includes linear, rod-shaped, serrated, etc.
[0009] Furthermore, the carrier is a carbon material or a conductive metal oxide; the loading method includes impregnation loading and blending and grinding loading.
[0010] Furthermore, the impregnation loading comprises: ultrasonically dispersing the PtFe alloy nanowires and the carrier in methanol, continuously stirring, centrifugally separating, and vacuum drying to obtain;
[0011] The mass ratio of the PtFe alloy nanowire to the carrier is (0.1-0.5):1.
[0012] As a preferred technical solution, the mass ratio of the PtFe alloy nanowires to the carrier is (0.2-0.3):1.
[0013] As a more preferred technical solution, the mass ratio of the PtFe alloy nanowires to the carbon material is 0.25:1.
[0014] As a preferred technical solution, in the vacuum drying, the drying temperature is 55 to 65° C. and the drying time is 20 to 40 minutes.
[0015] Furthermore, the carbon material is one of amorphous carbon powder, graphitized carbon powder or carbon nanotubes.
[0016] As a preferred technical solution, the carbon material is Xulcan XC-72 amorphous carbon powder.
[0017] Furthermore, in the vacuum heat treatment, the heat treatment pressure is 10 -5 ~10 -1 Pa, the heating rate is 5-30°C / min, the heat treatment temperature is 300-450°C, and the heat treatment time is 20-120min.
[0018] As a preferred technical solution, the heating rate is 10-15°C / min.
[0019] As a preferred technical solution, the heat treatment temperature is 350-400°C.
[0020] As a preferred technical solution, the heat treatment time is 30 to 50 minutes.
[0021] As a more preferred technical solution, in the vacuum heat treatment, the heat treatment pressure is 10 -3 Pa, the heating rate is 10℃ / min, the heat treatment temperature is 350℃, and the heat treatment time is 30min.
[0022] As a preferred technical solution, after the vacuum heat treatment, the material is cooled by furnace cooling to obtain a platinum-based nanomaterial having an intermetallic compound shell.
[0023] As a preferred technical solution, after the vacuum heat treatment, the platinum-based nanomaterials with intermetallic compound shells are collected and stored for future use without any washing process.
[0024] Furthermore, the preparation method of the PtFe alloy nanowires is selected from one of an oil phase synthesis method, a water phase synthesis method or a solid phase synthesis method.
[0025] Furthermore, the solid phase synthesis method comprises: dissolving a platinum source and an iron source together, drying, and calcining in a reducing gas atmosphere to obtain.
[0026] Furthermore, the platinum source is potassium chloroplatinite, the iron source is ferrous chloride tetrahydrate, and the mass ratio of the platinum source to the iron source is (82-84):(38-40).
[0027] Furthermore, the reducing gas atmosphere is a mixture of hydrogen and inert gas, and the volume content of hydrogen is 3-8%.
[0028] As a preferred technical solution, the volume content of hydrogen is 5%.
[0029] Furthermore, in the calcination, the calcination temperature is 230-280° C., and the calcination time is 20-40 min.
[0030] As a preferred technical solution, in the calcination, the calcination temperature is 250° C. and the calcination time is 30 min.
[0031] The present invention provides a low heating temperature (avoiding high temperature agglomeration) heat treatment phase change method, which utilizes a mild heat treatment method under low temperature conditions to achieve orderly reconstruction of the surface atoms of the alloy catalyst without destroying the original special morphology (linear, rod-shaped, serrated, etc.) of the platinum-based nanowires, thereby forming an intermetallic compound shell. The intermetallic compound shell has higher activity and stability. At the same time, since the heat treatment temperature is not high, it will not cause agglomeration and loss of performance, thereby comprehensively improving the catalytic activity and stability.
[0032] Compared with the prior art, one or more of the above technical solutions of the present invention can achieve at least one of the following beneficial effects:
[0033] (1) Achieve atomic ordering and reconstruction of the surface of metal nanomaterials without causing agglomeration of nanomaterials at high temperatures and without changing the original morphology and particle size of the nanomaterials;
[0034] (2) The intermetallic compound shell formed can effectively inhibit the corrosion and dissolution of transition metals during catalytic reactions in acidic systems, which is beneficial to improving the stability of electrocatalysts;
[0035] (3) The intermetallic compound shell is beneficial to the regulation of the adsorption energy of oxygen-containing groups during the electrocatalytic oxygen reduction process, thereby improving the catalytic activity of platinum-based nanomaterials for oxygen reduction reactions.
[0036] (4) The preparation method is simple, environmentally friendly, and does not require post-processing, making it suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 This is a transmission electron microscope photo of the PtFe alloy nanowires prepared in Example 1;
[0038] Figure 2 X-ray diffraction and transmission electron microscopy images of the PtFe alloy nanowires prepared in Example 1 before and after heat treatment;
[0039] Figure 3 The electrocatalytic oxygen reduction performance of the PtFe alloy nanowires and the PtFe alloy nanowires with an intermetallic compound shell prepared in Example 1;
[0040] Figure 4 TEM photos of PtFe alloy nanowires prepared in Comparative Examples 1 and 2. DETAILED DESCRIPTION
[0041] Aiming at the problem that the existing high-temperature heat treatment method for preparing platinum-based intermetallic compounds makes it difficult to maintain the original morphology and particle size of the nanomaterial during the heat treatment process, the present invention provides a method for preparing a platinum-based nanomaterial with an intermetallic compound shell at a low temperature, the method comprising the following steps:
[0042] Step S1, preparing a platinum-based nanowire material by an oil phase, water phase or solid phase synthesis method;
[0043] Step S2, loading the platinum-based nanomaterials onto amorphous carbon powder, conductive metal oxides or other carrier materials;
[0044] Step S3, spreading the nanomaterial powder supported by the carrier in a container and placing it in a vacuum reactor;
[0045] Step S4, performing low-temperature heat treatment on the nanomaterial to achieve ordered reconstruction of the atoms on the surface of the nanomaterial, and obtain a platinum-based nanomaterial with an intermetallic compound shell.
[0046] The present invention utilizes a mild heat treatment method under low temperature conditions to achieve ordered reconstruction of surface atoms of platinum-based nanomaterials without destroying the original special morphology (linear, rod-shaped, serrated, etc.) of the platinum-based nanomaterials, without causing agglomeration of the nanomaterials at high temperatures, and without changing the original morphology and particle size of the nanomaterials; the formed intermetallic compound shell can effectively inhibit the corrosion and dissolution of transition metals during catalytic reactions in an acidic system, which is beneficial to improving the stability of the electrocatalyst; the intermetallic compound shell is beneficial to the regulation of the adsorption energy of oxygen-containing groups during the electrocatalytic oxygen reduction process, and improves the catalytic activity of platinum-based nanomaterials for oxygen reduction reactions; the preparation method is simple, environmentally friendly, does not require post-treatment, and is suitable for large-scale production.
[0047] In a preferred embodiment, the carrier material is amorphous carbon powder, more preferably Xulcan XC-72. Xulcan XC-72 amorphous carbon powder has high conductivity and high specific surface area, and can uniformly load nanomaterials.
[0048] In a preferred embodiment, the loading method is stirring and mixing. Further preferably, the platinum-based nanomaterial and the carrier material are uniformly dispersed in methanol by ultrasound, stirred for 12 hours, and the carrier-supported nanomaterial is obtained by high-speed centrifugation, and dried in a vacuum oven at 60°C for 30 minutes.
[0049] In a preferred embodiment, in step S2, the mass ratio of platinum-based nanomaterial to carrier material is 0.25: 1. Too high a proportion of platinum-based nanomaterial will reduce its dispersibility on the carrier surface.
[0050] In a preferred embodiment, the container is a quartz boat or a porcelain boat, and the vacuum reactor is a vacuum tube furnace. Further preferably, the nanomaterial powder supported by the carrier should be spread as flatly as possible in the quartz boat or the porcelain boat so that it is heated evenly.
[0051] In a preferred embodiment, the vacuum reactor is a vacuum tube furnace. Further preferably, the flanges at both ends of the vacuum tube furnace are connected to a vacuum pump at one end and to a pressure indicator at the other end to indicate the vacuum degree in the furnace tube.
[0052] In a preferred embodiment, in step S3, the container loaded with the powder to be heat-treated is placed in the central area of the heating part of the vacuum reactor to ensure that it is in the constant temperature zone of the heating part of the tube furnace.
[0053] In a preferred embodiment, before the vacuum reactor temperature rise program is run, the vacuum pump is started to continuously evacuate the vacuum reactor for a long time until the air pressure in the vacuum reactor reaches 10 -3 Pa, to prevent the impurity atmosphere from changing the atomic reconstruction mode on the surface of the nanomaterial.
[0054] In a preferred embodiment, the vacuum reactor includes a vacuum tube furnace or a vacuum reactor.
[0055] In a preferred embodiment, in step S4, the heating rate is 10°C / min. If the heating rate is too fast, the temperature overshoot of the vacuum reactor is too large, affecting the heat treatment temperature control. If the heating rate is too slow, the heating time is long, which is not conducive to the large-scale production of nanomaterials.
[0056] In a preferred embodiment, in step S4, the heat treatment temperature is 350° C. If the heat treatment temperature is too low, the phase change degree of the nanomaterial is insufficient. If the heat treatment temperature is too high, the nanomaterial will agglomerate, and the morphology and particle size will also change.
[0057] In a preferred embodiment, in step S4, the heat treatment time is 30 minutes. If the heat treatment time is too short, the phase change degree of the nanomaterial is insufficient. If the heat treatment time is too long, the nanomaterial will agglomerate, and the morphology and particle size will also change.
[0058] In a preferred embodiment, after the heat treatment is completed, cooling is performed by cooling along with the furnace.
[0059] The low-temperature preparation method of the present invention has mild conditions and realizes ordered reconstruction of surface atoms without destroying the original morphology of the platinum-based nanomaterial. The prepared platinum-based nanomaterial with an intermetallic compound shell exhibits excellent oxygen reduction catalytic activity and stability. The preparation process is simple, the reaction is clean, and it is environmentally friendly, which is conducive to large-scale commercial applications.
[0060] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.
[0061] In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.
[0062] Embodiment 1:
[0063] A PtFe alloy nanowire with an intermetallic compound shell, the preparation method of which comprises the following steps:
[0064] (1) Preparation of PtFe alloy nanowires by solid phase method: 83.02 mg (0.2 mmol) of potassium chloroplatinate and 39.76 mg of ferrous chloride tetrahydrate were dissolved in 5 ml of deionized water, and then placed in a vacuum oven after ultrasonic treatment for 10 seconds to evaporate the water at 50°C, and then the solid powder of the pre-reactant was scraped off. The above solid powder was spread evenly in a quartz boat, and 20 μl of deionized water was dripped into it so that the powder could fully contact with the gas introduced into the reactor; argon was introduced into the reactor, and after 15 minutes, when the air in the reactor was exhausted, 5% hydrogen-argon mixed gas was introduced at a flow rate of hydrogen / argon (10 / 190) ml / min. At the same time, the temperature was raised from room temperature to 250°C at a rate of 10°C / min, and after 30 minutes of heat preservation, the temperature was naturally lowered to room temperature; after the reaction was completed, argon was introduced to exhaust the residual hydrogen in the reactor. The reduced solid powder was taken out, dispersed with deionized water, and centrifuged after ultrasonication. After this washing process was repeated twice, the sample was dispersed in anhydrous ethanol again and stored for later use.
[0065] (2) PtFe alloy nanowires were loaded onto Xulcan XC-72 amorphous carbon powder at a mass ratio of 0.25:1. The PtFe alloy nanowires and Xulcan XC-72 amorphous carbon powder were uniformly dispersed in methanol by ultrasound. After stirring at room temperature for 12 h, the carbon-supported PtFe alloy nanowires were obtained by high-speed centrifugation and dried in a vacuum oven at 60 °C for 30 min.
[0066] (3) The dried carbon-supported PtFe alloy nanowires were laid flat on a quartz boat and placed in a vacuum tube furnace. The vacuum tube furnace was evacuated for a long time by a vacuum pump until the pressure in the vacuum reactor reached 10 -3 Pa.
[0067] (4) After the pressure in the furnace tube stabilizes, the temperature is raised to 350°C at a heating rate of 10°C / min, and the carbon-supported PtFe alloy nanowires are subjected to constant temperature heat treatment for 30 min to achieve atomic ordering reconstruction on the surface of the nanomaterial.
[0068] (5) After the heat preservation is completed, the mixture is cooled naturally and the solid powder in the quartz boat is collected to obtain carbon-supported PtFe alloy nanowires with an intermetallic compound shell, which can be used without any post-treatment.
[0069] Application examples:
[0070] (1) Oxygen reduction performance test
[0071] First, the obtained catalyst was prepared into a uniform ink: 5 mg catalyst, 4 mL deionized water, 1 mL isopropanol, and 25 μL Nafion solution. The ink containing about 4 μg Pt was dropped on a 0.196 cm 2The test was conducted on a rotating disk electrode and dried naturally. The three-electrode test method was used to conduct a 0.05-1.0V voltammetric cycle scan test in an Ar-saturated 0.1M HClO4 aqueous solution, and a 0-1.1V polarization curve test in an O2-saturated 0.1M HClO4 aqueous solution.
[0072] (2) Stability test
[0073] The device was subjected to 30,000 accelerated cycle tests in the voltage range of 0.6-1.0 V, and then its oxygen reduction performance was tested again.
[0074] Figure 1 This is the structural and compositional characterization of the PtFe alloy nanowires obtained in Example 1. Figure 1 a is a low-magnification transmission electron micrograph of PtFe alloy nanowires, which can be hundreds of nanometers long. The inset on the lower left shows that the diameter of a single nanowire is about 3nm. Figure 1 b is a high-angle annular dark field-scanning transmission electron microscopy photo of a single PtFe alloy nanowire with atomic resolution. The exposed crystal plane of the nanowire under the observation direction
[110] is the (111) crystal plane. The dotted circle in the figure is some suspended atoms with low coordination numbers on the surface of the nanowire. The inset in the lower right corner is the fast Fourier transform result corresponding to a single PtFe alloy nanowire. Its single crystal diffraction pattern proves that the alloy nanowire belongs to a typical face-centered cubic structure. Figure 1 c The interplanar spacing of the (111) crystal plane of PtFe alloy nanowires was measured to be 0.21 nm. Figure 1 d is the surface scanning element distribution diagram of PtFe alloy nanowires. It can be seen that Pt and Fe are evenly distributed in the nanowires.
[0075] Figure 2 This is the structural characterization of the PtFe alloy nanowires obtained in Example 1 and the PtFe alloy nanowires with an intermetallic compound shell. Figure 2 In the XRD results of a, the (220) crystal plane diffraction peak of the heat-treated PtFe alloy nanowire sample is slightly shifted to the right compared with the commercial Pt / C and original PtFe alloy nanowire samples, and the low-index (100) and (110) diffraction peaks corresponding to intermetallic compounds are not found. Figure 2 (bd) and (eg) are low-magnification transmission electron microscopy images of carbon-supported PtFe alloy nanowires before and after heat treatment, high-angle annular dark field-scanning transmission electron microscopy images and the corresponding atomic schematic models, respectively. Figure 2 In figure f, a typical L12 phase feature of eight bright atoms surrounding one dark atom is formed on the surface of the nanowire, proving the formation of a Pt3Fe intermetallic compound shell on the surface.
[0076] Figure 3The electrocatalytic oxygen reduction performance of the PtFe alloy nanowires obtained in Example 1, the PtFe alloy nanowires with intermetallic compound shells and commercial Pt / C is compared. The mass activity of the PtFe alloy nanowires with intermetallic compound shells is 1.5 times and 3.3 times that of the PtFe alloy nanowires and commercial Pt / C, respectively, and the area activity is 2.0 times and 9.7 times that of the PtFe alloy nanowires and commercial Pt / C, respectively. The PtFe alloy nanowires with intermetallic compound shells also show excellent acid resistance and stability. After 30,000 cycles of stability testing, the half-wave potential in its polarization curve shifts to the left by only 3mV, and the electrochemical active area remains basically unchanged. At 0.9V, the mass activity and area activity only lose 12.2% and 19.5%, respectively. The detailed data of the electrocatalytic oxygen reduction performance are shown in Table 1.
[0077] Table 1
[0078]
[0079] Comparative Example 1:
[0080] A PtFe nanowire, the preparation method thereof is different from that of Example 1 in that:
[0081] In step (4), after the pressure in the furnace tube is stabilized, the temperature is raised to 500° C. at a heating rate of 10° C. / min, and the carbon-supported PtFe alloy nanowires are subjected to a constant temperature heat treatment for 30 min. The remaining steps are consistent with those in Example 1.
[0082] Figure 4 a is the structural characterization of the PtFe alloy nanowires prepared in Comparative Example 1. Part of the nanowire structure has been broken.
[0083] Comparative Example 2:
[0084] A PtFe nanowire, the preparation method thereof is different from that of Example 1 in that:
[0085] In step (4), after the pressure in the furnace tube is stabilized, the temperature is raised to 600° C. at a heating rate of 10° C. / min, and the carbon-supported PtFe alloy nanowires are subjected to a constant temperature heat treatment for 30 min. The remaining steps are consistent with those in Example 1.
[0086] Figure 4 b is the structural characterization of the PtFe alloy nanowires prepared in Comparative Example 2. All nanowire structures have been broken.
[0087] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.
Claims
1. A method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature, characterized in that: The method comprises: loading PtFe alloy nanowires on a carrier and performing vacuum heat treatment at 350-400°C to obtain the nanowires.
2. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 1, characterized in that: The carrier is a carbon material or a conductive metal oxide; the loading method includes impregnation loading and blending and grinding loading.
3. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 2, characterized in that: The impregnation loading comprises: ultrasonically dispersing the PtFe alloy nanowires and the carrier in methanol, continuously stirring, centrifugally separating, and vacuum drying; The mass ratio of the PtFe alloy nanowire to the carrier is (0.1-0.5):
1.
4. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 2, characterized in that: The carbon material is one of amorphous carbon powder, graphitized carbon powder or carbon nanotubes.
5. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 1, characterized in that: In the vacuum heat treatment, the heat treatment pressure is 10 -5 ~10 -1 Pa, the heating rate is 5-30°C / min, the heat treatment temperature is 300-450°C, and the heat treatment time is 20-120min.
6. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 1, characterized in that: The preparation method of the PtFe alloy nanowires is selected from one of an oil phase synthesis method, a water phase synthesis method or a solid phase synthesis method.
7. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 6, characterized in that: The solid phase synthesis method comprises: dissolving a platinum source and an iron source together, drying, and calcining in a reducing gas atmosphere to obtain the platinum source.
8. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 7, characterized in that: The platinum source is potassium chloroplatinite, the iron source is ferrous chloride tetrahydrate, and the mass ratio of the platinum source to the iron source is (82-84):(38-40).
9. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 7, characterized in that: The reducing gas atmosphere is a mixture of hydrogen and inert gas, and the volume content of hydrogen is 3-8%.
10. The method for preparing PtFe alloy nanowires with an intermetallic compound shell at low temperature according to claim 7, characterized in that: In the calcination, the calcination temperature is 230-280° C. and the calcination time is 20-40 min.