Carbon-loaded palladium-tin intermetallic compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of hydrogen energy and fuel cell catalyst preparation, and particularly relates to a carbon-loaded palladium-tin intermetallic compound and a preparation method and application thereof. The preparation method comprises the following steps: dispersing palladium salt, tin salt and a carbon carrier in a solvent, ultrasonically mixing, heating until the solvent is evaporated, drying an obtained solid product, and grinding to obtain precursor solid powder; and heating and reducing the precursor solid powder in a reducing atmosphere to obtain the carbon-loaded palladium-tin intermetallic compound. By introducing low-melting-point and relatively-cheap metallic tin, not only can the formation temperature of intermetallic compounds be reduced and the energy consumption be reduced, but also more OH and CO adsorption and desorption sites can be provided by doping the tin element, the electro-catalytic activity and the CO poisoning resistance can be improved, and the preparation method is simple and easy to implement. The problems that hydrogen energy and fuel cell catalysts are poor in activity, the preparation method is tedious, and the CO poisoning resistance is poor are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to catalysts, and more specifically, relates to a carbon-supported palladium-tin intermetallic compound and a preparation method and application thereof. Background Art

[0002] In recent years, global demand for energy, particularly traditional fossil fuels, has continued to increase. However, fossil fuels are non-renewable energy sources, and overuse can lead to their gradual depletion. Furthermore, the combustion of fossil fuels can exacerbate the greenhouse effect. Therefore, the development of green and renewable energy is urgent. Currently, various renewable energy sources, such as wind, solar, and tidal power, have been developed and utilized. However, the sources of these renewable energy sources are affected by seasonality, weather, and other factors, resulting in unstable power supply frequencies. Hydrogen production technologies are more stable and efficient than other renewable energy technologies. Given their high energy density, cleanliness, and pollution-free nature, hydrogen is an ideal clean and viable energy carrier. Currently, efficient and large-scale hydrogen utilization can be achieved through fuel cells. Among fuel cell applications, proton exchange membrane fuel cells (PEMFCs) are considered a relatively mature fuel cell technology. However, their cathode oxygen reduction reaction (ORR) catalyst relies heavily on scarce and expensive platinum, which limits their widespread application. Anion exchange membrane fuel cells (AEMFCs) offer advantages over PEMFCs in catalyst cost control, operating temperature range, water management, and membrane material sustainability, and their performance improvements have also attracted widespread attention. The power density of anion exchange membrane fuel cells (AEMFCs) is currently primarily limited by the anode HOR reaction rate, which is typically 2-3 orders of magnitude slower than in acidic media. Currently, most anode HOR catalysts use Pt-based catalysts, but these also suffer from high cost and poor resistance to CO poisoning. To reduce the anode HOR's reliance on Pt-based catalysts, the search for alternative AEMFC anode catalysts with high catalytic activity, high stability, and excellent resistance to CO poisoning is a key research direction.

[0003] Fuel cells can use more than just hydrogen as a fuel. Ethanol can also be used as a fuel cell due to its readily available, non-toxic, pollution-free combustion characteristics, and the ability to generate significant energy upon complete oxidation. This has led to the rapid development of direct ethanol fuel cells (DEFCs) fueled by ethanol in recent years. The power density of alkaline direct ethanol fuel cells primarily depends on the ethanol oxidation reaction (EOR) at the anode. Ethanol oxidation requires breaking carbon-carbon bonds for complete oxidation. While the bond energy of carbon-carbon bonds is relatively low, the steric hindrance slows down the rate of ethanol oxidation. Furthermore, the byproducts produced by incomplete oxidation (such as acetaldehyde and acetic acid) further hinder the complete conversion of ethanol to carbon dioxide. Therefore, the development of catalysts with high catalytic activity and stability for EOR will be a key issue for the widespread application of direct ethanol fuel cells.

[0004] Both the HOR reaction at the anode of anion exchange membrane fuel cells and the EOR reaction at the anode of alkaline direct ethanol fuel cells are currently highly dependent on Pt-based catalysts. Therefore, there is an urgent need to develop highly active and stable intermetallic compound catalysts for HOR at the anode of anion exchange membrane fuel cells and EOR at the anode of alkaline direct ethanol fuel cells, effectively breaking the over-reliance on Pt-based catalysts for fuel cell catalysts. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a carbon-supported palladium-tin intermetallic compound and its preparation method and application. Its purpose is to develop a multifunctional palladium-based catalyst to effectively solve the problems of poor catalyst activity, cumbersome preparation methods, and poor resistance to CO poisoning in alkaline HOR and EOR.

[0006] To achieve the above object, according to a first aspect of the present invention, the present invention first provides a method for preparing a carbon-supported palladium-tin intermetallic compound, comprising the following steps:

[0007] (1) dispersing palladium salt, tin salt and carbon support in a solvent and ultrasonically mixing them, heating to evaporate the solvent, drying the obtained solid product and then grinding it to obtain a precursor solid powder;

[0008] (2) The precursor solid powder is heated and reduced in a reducing atmosphere to obtain a carbon-supported palladium-tin intermetallic compound.

[0009] Preferably, the heating rate in the heating reduction is 5 to 10° C. / min, the heating reduction temperature is 400 to 800° C., and the heating reduction time is 4 to 8 hours.

[0010] Preferably, the mass fraction of palladium element in the precursor solid powder is 20-40%.

[0011] Preferably, the atomic ratio of palladium element to tin element in the precursor solid powder is 1:(1-1.5).

[0012] Preferably, the palladium salt is at least one of palladium chloride, palladium acetylacetonate, and palladium acetate; and the tin salt is at least one of tin dichloride, tin tetrachloride, tin acetate, and tin acetylacetonate.

[0013] Preferably, the solvent is at least one of water and ethanol, the ultrasonic stirring time is 0.5 to 2 hours, and the heating temperature is 55 to 70°C.

[0014] The carbon carrier is at least one of carbon black, graphene, carbon nanotubes, and carbon nanowires.

[0015] Preferably, the reducing atmosphere is an argon-hydrogen mixed gas; wherein the volume proportion of the hydrogen in the reducing atmosphere is 5-10%.

[0016] According to another aspect of the present invention, a carbon-supported palladium-tin intermetallic compound is provided. The carbon-supported palladium-tin intermetallic compound is prepared by the preparation method described in the first aspect of the present invention.

[0017] According to another aspect of the present invention, there is provided an application of a carbon-supported palladium-tin intermetallic compound as described in another aspect of the present invention, which is used as a catalyst for the anode hydrogen oxidation reaction of an alkaline anion exchange membrane fuel cell, or a catalyst for the ethanol oxidation reaction of an alkaline direct ethanol fuel cell.

[0018] In general, the above technical solutions conceived by the present invention have the following technical advantages compared with the existing technology:

[0019] (1) The present invention introduces low-melting-point, inexpensive metallic tin into the palladium-based catalyst, which can reduce the synthesis temperature of the intermetallic compound and reduce energy consumption. At the same time, the doping of tin can provide more OH and CO adsorption and desorption sites, thereby improving the electrocatalytic activity and resistance to CO poisoning, and effectively solving the problem of over-reliance on Pt-based catalysts in alkaline HOR and EOR.

[0020] (2) The present invention controls the temperature of the reduction reaction to be between 400°C and 800°C, and the reduction time to be 4 to 8 hours, preferably the reduction temperature to be between 400°C and 600°C, thereby obtaining a carbon-supported palladium-tin intermetallic compound with excellent performance. Moreover, based on the lower generation temperature, the increase in particle size is avoided, which will reduce the active sites of the material and thus avoid the decrease in catalyst activity.

[0021] (3) The preparation method of the present invention has the unique advantages of low energy consumption, simplicity, high efficiency, mildness, low cost, and strong repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 These are the X-ray diffraction (XRD) patterns of the carbon-supported palladium-tin intermetallic compound at reduction temperatures of 400° C., 500° C., and 600° C. in Example 1.

[0023] Figure 2 This is the X-ray photoelectron spectroscopy (XPS) spectrum of the carbon-supported palladium-tin intermetallic compound at a reduction temperature of 400° C. in Example 1.

[0024] Figure 3 These are the HOR-linear voltammetric polarization (LSV) curves of the carbon-supported palladium-tin intermetallic compound at reduction temperatures of 400°C, 500°C, and 600°C in Example 1. The electrolyte solution is 0.1M KOH solution, and the gas introduced during the test is high-purity H2 (99.999%).

[0025] Figure 4 : This is the HOR-LSV curve of the carbon-supported palladium-tin intermetallic compound at a reduction temperature of 400°C in Example 1. The electrolyte solution is 0.1M KOH solution. As a comparative test, the gases introduced during the test are high-purity H2 and high-purity H2+1000ppm CO, respectively.

[0026] Figure 5 This is the EOR-cyclic voltammetry (CV) curve of the carbon-supported palladium-tin intermetallic compound at reduction temperatures of 400°C, 500°C, and 600°C in Example 1. The electrolyte solution is 1M KOH+1M C2H5OH solution, and the gas introduced during the test is N2. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0028] Example 1

[0029] The present embodiment provides a carbon-supported palladium-tin intermetallic compound, the preparation method of which is as follows: 28.8 mg of Vulcan carbon is uniformly dispersed in 10 mg of palladium chloride and tin tetrachloride aqueous solution, ultrasonically stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonically evaporated to dryness under 65 ° C to obtain a solid product, and the solid product is ground in an agate mortar to obtain a precursor solid powder (wherein the mass fraction of Pd is 20%, and the atomic ratio of palladium and tin is 1:1.5). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%), the heating rate is 10 ° C / min, the reduction temperature gradient is 400 ° C, 500 ° C, and 600 ° C, respectively, and the reduction time is 4 hours.

[0030] Comparative Example 1

[0031] This comparative example provides a carbon-supported palladium element as a comparative sample, which is prepared as follows: 40 mg of Vulcan carbon is uniformly dispersed in 5 ml of palladium chloride aqueous solution, and ultrasonicated and stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonicated at 65°C until the aqueous solvent is evaporated to dryness to obtain a precursor solid powder (wherein the mass fraction of Pd is 20%). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%) at a heating rate of 10°C / min, a reduction temperature of 150°C, and a reduction time of 2 hours.

[0032] Comparative Example 2

[0033] This comparative example provides a carbon-supported platinum sample as a comparative sample. The preparation method is as follows: 40 mg of Vulcan carbon is uniformly dispersed in 5 ml of aqueous chloroplatinic acid solution and stirred with sonication for 30 minutes. The resulting mixed solution is stirred and sonicated at 65°C until the aqueous solvent is evaporated to dryness, thereby obtaining a precursor solid powder (containing a Pt mass fraction of 20%). The resulting precursor solid powder is then reduced in an Ar / H2 mixed atmosphere (with a H2 volume ratio of 5%) at a heating rate of 10°C / min, a reduction temperature of 150°C, and a reduction time of 2 hours.

[0034] Example 2

[0035] The present embodiment provides a carbon-supported palladium-tin intermetallic compound, the preparation method of which is as follows: 28.8 mg of Vulcan carbon is uniformly dispersed in 10 mg of palladium chloride and tin tetrachloride ethanol solution, and ultrasonicated and stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonicated at 65°C until the water solvent is evaporated to dryness to obtain a solid product, and the solid product is ground in an agate mortar to obtain a precursor solid powder (wherein the mass fraction of Pd is 20% and the atomic ratio of palladium and tin is 1:1). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%), the heating rate is 10°C / min, the reduction temperature is 400°C, and the reduction time is 4 hours.

[0036] Example 3

[0037] The present embodiment provides a carbon-supported palladium-tin intermetallic compound, the preparation method of which is as follows: 28.8 mg of Vulcan carbon is uniformly dispersed in 10 mg of palladium chloride and tin dichloride ethanol solution, ultrasonically stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonically evaporated to dryness under 65°C to obtain a solid product, and the solid product is ground in an agate mortar to obtain a precursor solid powder (wherein the mass fraction of Pd is 20% and the atomic ratio of palladium and tin is 1:1). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%), the heating rate is 10°C / min, the reduction temperature is 400°C, and the reduction time is 4 hours.

[0038] When the tin salt is tin dichloride, it easily reacts with palladium chloride in water, so the solvent for preparing the precursor is selected to be ethanol solvent.

[0039] Examples 2 and 3 can achieve performance comparable to that of the catalyst prepared at a reduction temperature of 400°C in Example 1.

[0040] Comparative Example 3

[0041] The present embodiment provides a carbon-supported palladium-tin intermetallic compound, the preparation method of which is as follows: 39.6 mg of Vulcan carbon is uniformly dispersed in 5 mg of palladium chloride and tin dichloride ethanol solution, ultrasonically stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonically evaporated to dryness under 65°C to obtain a solid product, and the solid product is ground in an agate mortar to obtain a precursor solid powder (wherein the mass fraction of Pd is 10% and the atomic ratio of palladium and tin is 1:1). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%), with a heating rate of 10°C / min, a reduction temperature of 400°C, and a reduction time of 4 hours.

[0042] Comparative Example 4

[0043] The present embodiment provides a carbon-supported palladium-tin intermetallic compound, the preparation method of which is as follows: 39.6 mg of Vulcan carbon is uniformly dispersed in 5 mg of palladium chloride and tin dichloride ethanol solution, ultrasonically stirred for 30 minutes. The resulting mixed solution is stirred and ultrasonically evaporated at 65°C until the water solvent is evaporated to dryness to obtain a solid product, and the solid product is ground in an agate mortar to obtain a precursor solid powder (wherein the mass fraction of Pd is 10% and the atomic ratio of palladium and tin is 1:1). The obtained precursor solid powder is reduced in an Ar / H2 mixed atmosphere (the volume ratio of H2 in the Ar / H2 mixed atmosphere is 5%), the heating rate is 5°C / min, the reduction temperature is 600°C, and the reduction time is 6 hours.

[0044] Comparative Examples 3 and 4 were inferior to the performance of Comparative Example 1.

[0045] In the method disclosed in the present invention, the solvent includes water, ethanol or an ethanol solvent having a mixed performance of the two in any proportion. In the above embodiments 2-5, the volume percentage of ethanol in the ethanol solution is about 50%.

[0046] It should be noted that when the mass fraction of Pd in ​​the present invention is 20-40% and the atomic ratio of palladium to tin is 1:(1-1.5), it can ensure the sufficient formation of carbon-supported palladium-tin intermetallic compounds. Within this range, the higher the loading of palladium and tin, the better the performance of the corresponding catalyst.

[0047] Application Testing

[0048] The carbon-supported palladium-tin intermetallic compound of Example 1 and the carbon-supported palladium and carbon-supported platinum prepared in Comparative Examples 1 and 2 were subjected to alkaline HOR and EOR tests.

[0049] For alkaline HOR testing, 1 mg of catalyst powder and 3 mg of Vulcan carbon powder were added to 1 mL of isopropanol / Nafion mixed solution to prepare ink (Nafion mass fraction was 0.1%). The ink was ultrasonically mixed for 15 min. 5 μL of ink was measured using a microinjector and applied to the surface of a glassy carbon electrode in small amounts and multiple times, and dried naturally in air. This was used as the working electrode, the carbon rod as the auxiliary electrode, and the reversible hydrogen electrode as the reference electrode. The electrolyte solution was a freshly prepared 0.1 M KOH electrolyte. H2 was passed through the 0.1 M KOH electrolyte for 20 min to saturate it. The speed was set to 1600 rpm, and the voltage range of -0.05 to 0.6 V was scanned at a rate of 0.005 V s. -1 Scan to obtain the LSV curve.

[0050] For alkaline EOR testing, 1 mg of catalyst powder and 3 mg of Vulcan carbon powder were added to 1 mL of isopropanol / Nafion mixed solution to prepare ink (Nafion mass fraction was 0.1%). The ink was ultrasonically mixed for 15 min. 5 μL of ink was measured using a microinjector and applied to the surface of a glassy carbon electrode in small amounts and multiple times, and dried naturally in air. This was used as the working electrode, the carbon rod as the auxiliary electrode, and the reversible hydrogen electrode as the reference electrode. The electrolyte solution was a freshly prepared 1 mol / L KOH + 1 mol / L C2H5OH electrolyte. N2 was passed through the electrolyte for 20 min to saturate it, and the voltage range of 0.05 to 1.2 V was scanned at a rate of 0.05 V s. -1 The cyclic voltammetry curve was obtained by scanning.

[0051] Figure 1 Figure 2 shows the XRD patterns of the carbon-supported palladium-tin intermetallic compound (PdSn / C) at different reduction temperatures in Example 1. The broad peak at around 26° is attributed to the diffraction peak of the (002) plane of the carbon support. Meanwhile, PdSn exhibits distinct diffraction peaks at angles of 30.7°, 32.2°, 37.4°, 39.7°, 40.0°, 40.1°, 47.0°, 49.2°, and 57.9°, corresponding to the (111), (012), (120), (112), (121), (022), (200), (103), and (212) planes of cubic PdSn, respectively. These diffraction peaks can be well indexed to body-centered cubic PdSn (PDF No. 00-004-0803). The Sn atoms occupy the eight vertices of the unit cell, while the Pd atoms are located in the center of the main body, confirming the successful synthesis of PdSn / C; and the one-to-one correspondence between the material lattice diffraction peaks and the standard PDF card proves that PdSn is a pure phase palladium-tin intermetallic compound.

[0052] Figure 2 This is the X-ray photoelectron spectroscopy (XPS) spectrum of PdSn / C at a reduction temperature of 400°C in Example 1. From the figure, it can be seen that four elements, Pd, Sn, C, and O, are present in the sample. The presence of the O element may be due to the formation of tin oxide on the surface of the sample due to exposure to air.

[0053] Figure 3The HOR-LSV polarization curves of PdSn / C at different reduction temperatures in Example 1 and carbon-supported palladium (Pd / C) in Comparative Example 1 show that the HOR performance of the PdSn intermetallic compound in Example 1 is excellent, indicating that with the introduction of the Sn element, the intermetallic compound can be formed at a lower reaction temperature and the catalytic activity of the material is improved. Among them, the HOR performance of the PdSn intermetallic compound at reduction temperatures of 400°C and 500°C is stronger than that of Pd / C, and when the reduction temperature is 400°C, the material has the maximum current density at 50mV overpotential and is more active. As the reduction temperature increases, the activity of the catalyst decreases. This is because the increase in particle size caused by the increase in reduction temperature reduces the active sites of the material, thereby reducing the activity of the catalyst.

[0054] Figure 4 The HOR-LSV polarization curves for the PdSn / C catalyst from Example 1 and the carbon-supported palladium (Pd / C) from Comparative Example 1 at 400°C under saturated H₂ and saturated H₂ + 1000ppm CO conditions are shown. The figure shows that under saturated H₂ + 1000ppm CO, the PdSn / C catalyst maintains a relatively high current density around 0.4V, only decreasing by approximately 20% compared to the current density under saturated H₂, while the Pd / C catalyst exhibits a 60% decrease. This indicates that the PdSn / C catalyst maintains a relatively high catalytic activity compared to the Pd / C catalyst under CO poisoning, demonstrating superior resistance to CO poisoning.

[0055] Figure 5 The EOR-CV curves of the carbon-supported palladium-tin intermetallic compound at 400°C, 500°C, and 600°C reduction temperatures in Example 1 are shown. The CV curves of all materials contain two redox peaks, of which the left peak is the Pd / Pt-CO ad The peak on the right is the reduction peak of ethanol molecules, and the peak on the right is the oxidation peak of ethanol molecules. By comparing the peak values ​​of the ethanol molecule oxidation peaks, we can qualitatively derive the ethanol oxidation ability of the material. By comparison, we can find that the ethanol oxidation performance of the PdSn intermetallic compound is stronger than that of Pt / C and Pd / C at the reduction temperatures of 400℃, 500℃, and 600℃. In particular, when the reduction temperature is 400℃, the ethanol oxidation activity of the material reaches its peak, with a current density peak of 17.5mA / cm at around 0.8V. -2 , which is significantly better than the comparison sample Pd / C (7.5mA / cm -2 ) and Pt / C(9mA / cm -2 ), indicating that the introduction of Sn enhances the catalytic activity of the material. Meanwhile, the activity of the catalyst decreases with increasing reduction temperature. This is because the increase in particle size caused by the increase in reduction temperature reduces the number of active sites in the material, leading to a decrease in catalyst activity.

[0056] In summary, the present invention introduces the cheap and readily available Sn element into Pd and successfully synthesizes a PdSn intermetallic compound through a simple impregnation reduction plus high-temperature annealing method. Furthermore, through exploration of temperature, feed ratio, and calcination time, it was found that the PdSn intermetallic compound obtained at 400°C has better catalytic activity and resistance to CO poisoning than Pd / C in alkaline HOR. Its ethanol oxidation ability in alkaline EOR is significantly better than that of Pt / C and Pd / C, indicating its potential for large-scale preparation and application.

[0057] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such modifications and variations fall within the scope of the present invention and its equivalents, the present invention is intended to encompass such modifications and variations. The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention and are not intended to limit the scope of protection. Any equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-supported palladium-tin intermetallic compound, characterized in that: The following steps are included: (1) dispersing palladium salt, tin salt and carbon support in a solvent and ultrasonically mixing them, heating to evaporate the solvent, drying the obtained solid product and then grinding it to obtain a precursor solid powder; (2) The precursor solid powder is heated and reduced in a reducing atmosphere to obtain a carbon-supported palladium-tin intermetallic compound.

2. The method for preparing a carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The heating rate in the heating reduction is 5-10° C. / min, the heating reduction temperature is 400-800° C., and the heating reduction time is 4-8 hours.

3. The method for preparing the carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The mass fraction of palladium element in the precursor solid powder is 20-40%.

4. The method for preparing a carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The atomic ratio of palladium element to tin element in the precursor solid powder is 1:(1-1.5).

5. The method for preparing the carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The solvent is at least one of water and ethanol, the ultrasonic stirring time is 0.5 to 2 hours, and the heating temperature is 55 to 70°C.

6. The method for preparing the carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The palladium salt is at least one of palladium chloride, palladium acetylacetonate, and palladium acetate; the tin salt is at least one of tin dichloride, tin tetrachloride, tin acetate, and tin acetylacetonate.

7. The method for preparing a carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The carbon carrier is at least one of carbon black, graphene, carbon nanotubes, and carbon nanowires.

8. The method for preparing a carbon-supported palladium-tin intermetallic compound according to claim 1, wherein The reducing atmosphere is an argon-hydrogen mixed gas; wherein the volume proportion of the hydrogen in the reducing atmosphere is 5-10%.

9. A carbon-supported palladium-tin intermetallic compound, characterized in that: The carbon-supported palladium-tin intermetallic compound is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the carbon-supported palladium-tin intermetallic compound according to claim 9, characterized in that: Used as catalyst for hydrogen oxidation reaction at the anode of alkaline anion exchange membrane fuel cells, or as catalyst for ethanol oxidation reaction in alkaline direct ethanol fuel cells.

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