Palladium-lead alloy nanowire, palladium-lead alloy nanowire catalyst and preparation method thereof

Abstract

The invention discloses a palladium-lead alloy nanowire, a palladium-lead alloy nanowire catalyst and a preparation method thereof. Ethanol is used as a reaction solvent, polyvinyl pyrrolidone is used as a surfactant, hexadecyltrimethylammonium chloride is used as a coordination agent, hexacarbonyl tungsten is used as a reducing agent, palladium acetylacetonate is used as a palladium source, and lead chloride is used as a lead source to prepare defect-rich high-activity palladium-lead alloy nanowires, and the palladium-lead alloy nanowires are subjected to structural characterization and performance testing. An efficient electrocatalyst is prepared in a carbon-supported manner for electrochemical performance testing. The invention prepares palladium-lead alloy nanowires with controllable morphology, high specific surface area and abundant active sites through a simple and easy, green chemical optimized synthesis method, and then the catalyst is measured by an electrochemical method to have good ORR electrocatalytic activity. The palladium-lead alloy nanowire catalyst can be used as a cathode electrocatalyst for fuel cells and has good electrochemical performance.

Description

Technical Field

[0001] The invention relates to the field of fuel cell cathode catalysts, in particular to a palladium-lead alloy nanowire, a palladium-lead alloy nanowire catalyst and a preparation method thereof. Background Art

[0002] At present, with the gradual reduction of global fossil energy (non-renewable energy) reserves and the worsening environmental pollution caused by fossil energy, it is becoming increasingly important for people to develop storage systems and energy conversion in clean energy technologies. Among various green energy technologies, fuel cells are considered to be one of the most promising energy conversion devices due to their high energy density, high stability, environmental friendliness, wide sources and low cost. However, as the key cathode reaction in fuel cells, the performance of oxygen reduction reaction (ORR) will directly affect the conversion efficiency and output power of the entire fuel cell device. Therefore, the development of efficient cathode ORR electrocatalysts is a necessary condition for improving fuel cell performance and large-scale application. At present, most high-performance ORR electrocatalysts reported by research institutes are basically Pt-based nanocatalysts. This is due to the unique physicochemical properties of Pt, which is conducive to promoting the rapid kinetics of ORR reaction. Therefore, in terms of ORR reaction activity, Pt-based catalysts are the first choice for cathode reaction catalysts in current fuel cells. However, Pt-based catalysts have problems such as scarce reserves, high cost, and easy poisoning, which seriously hinder the application and popularization of fuel cells. Therefore, it is urgent to develop a non-Pt-based electrocatalyst with abundant reserves, low cost and good ORR catalytic performance.

[0003] In recent years, people have been committed to developing various high-efficiency non-Pt-based ORR catalysts with abundant reserves and low cost. Among them, palladium (Pd)-based catalysts are regarded as the most promising electrocatalysts to replace Pt-based ones. This is because Pd belongs to the same element family as Pt and has a lattice constant and valence electron structure similar to Pt. In addition, Pd also has the advantages of relatively abundant reserves and strong anti-poisoning performance. It is worth noting that people have found through DFT calculations and experimental studies that under alkaline conditions, although pure Pd is excessively combined with oxygen-containing species, resulting in relatively poor catalytic activity, the electronic structure of the Pd surface can be effectively adjusted by alloying or interface regulation, thereby optimizing the binding energy with the reaction intermediates, and then obtaining ORR performance that is not inferior to Pt. In view of these challenges, Pd-based nanocatalysts must be optimized and regulated to give Pd-based NCs an electronic structure that is conducive to catalytic reactions, so that they can provide suitable adsorption energy for the reaction intermediates of oxygen reduction.

[0004] Studies have shown that the electronic structure of Pd-based NCs can be improved by introducing other elements. The ligand effect produced by the introduced elements can enhance the effective charge transfer between different atoms, thereby enhancing its intrinsic electrocatalytic activity. In addition, electrochemical reactions usually occur on the surface of the catalyst, which makes increasing the number of electrocatalytic active sites of Pd-based catalysts an effective research strategy to improve the intrinsic electrocatalytic activity of the catalyst.

[0005] In order to maximize the number of suitable active adsorption sites for reactants or intermediates, existing research strategies have proposed advanced strategies such as constructing geometric structures, modifying surfaces, and regulating interface engineering to enhance the intrinsic activity of catalysts and provide more surface active sites. Nanoelectrocatalysts are often divided into four types of nanocrystals: zero-dimensional, one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D), such as nanoparticles, nanowires, nanosheets, and nanoframes. It is worth noting that one-dimensional nanostructures provide a good geometric basis for improving the activity of nanoelectrocatalysts due to their advantages such as large specific surface area and rich active sites. At the same time, in electrocatalytic reactions, one-dimensional nanostructures can also promote electron transport, improve electrical conductivity and mass transfer rate, thereby optimizing the reaction kinetics on the surface of the electrocatalyst and achieving the purpose of improving intrinsic activity. Studies have shown that one-dimensional defect-rich Pd-based nanowires are often used as good ORR catalysts due to their rich defect sites, high specific surface area, and efficient mass transfer pathways. For example, PdNi NWs, Pd 4 Sn NWs, PdAu NWs, and PdIr NWs, etc. In view of this, developing a simple synthesis route for one-dimensional defect-rich Pd-based nanowires provides a research strategy for the construction of highly active non-Pt-based ORR catalysts in the future, which is of great scientific significance. Summary of the invention

[0006] In view of the above technical problems, the embodiments of the present application propose a palladium-lead alloy nanowire, a palladium-lead alloy nanowire catalyst and a preparation method thereof to solve the above problems.

[0007] According to the first aspect, the present application proposes a method for preparing palladium-lead alloy nanowires, comprising the following steps:

[0008] 1) Add palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten and polyvinylpyrrolidone-55000 to ethanol, and stir at room temperature until the mixture is uniform;

[0009] 2) raising the temperature of the solution obtained in step 1 from room temperature to 170-190° C. over 40-50 minutes and maintaining the temperature for 80-100 minutes, and then cooling the solution naturally to room temperature;

[0010] 3) The solution obtained in step 2 is washed and collected by centrifugation to obtain palladium-lead alloy nanowires, which are then stored in an ethanol solution.

[0011] Preferably, the temperature of the solution obtained in step 1 is raised from room temperature to 180° C. over 45 minutes and maintained for 90 minutes, and then naturally cooled to room temperature.

[0012] Preferably, the ratio of palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, tungsten hexacarbonyl, polyvinylpyrrolidone-55000 and ethanol in step 1 is 9-11 mg: 9-11 mg: 20-30 mg: 20-30 mg: 90-110 mg: 11-13 mL, wherein the purity of ethanol is above 99.7%.

[0013] Preferably, the ratio of palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, tungsten hexacarbonyl, polyvinylpyrrolidone-55000 and ethanol in step 1 is 10 mg: 10 mg: 25 mg: 25 mg: 100 mg: 12 mL, wherein the purity of ethanol is above 99.7%.

[0014] Preferably, the concentration of the noble metal in the ethanol solution in step 3 is 1 mg / mL Pd .

[0015] According to the second aspect, the present application proposes a palladium-lead alloy nanowire, which is produced by the preparation method of the palladium-lead alloy nanowire of the first aspect.

[0016] Preferably, the crystal form of the lead alloy nanowires is a face-centered cubic structure, and the diameter of the lead alloy nanowires ranges from 6 to 10 nm.

[0017] According to the third aspect, the present application provides a method for preparing a palladium-lead alloy nanowire catalyst, comprising the method for preparing the palladium-lead alloy nanowire of the first aspect, and further comprising: preparing the palladium-lead alloy nanowire at a concentration of 15 to 25% by weight. Pd The loading amount was loaded on superconducting activated carbon to prepare palladium-lead alloy nanowire catalyst.

[0018] As a preference, the palladium-lead alloy nanowires are prepared at 20% wt. Pd The loading amount was loaded on superconducting activated carbon to prepare palladium-lead alloy nanowire catalyst

[0019] According to a fourth aspect, the present application proposes a palladium-lead alloy nanowire catalyst, which is produced using the above-mentioned preparation method of the palladium-lead alloy nanowire catalyst.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention prepares palladium-lead alloy nanowires with controllable components, high specific surface area and abundant active sites through a simple, easy and green chemical method, and prepares efficient electrocatalysts in a carbon-supported manner. Relevant electrochemical tests show that the catalyst has abundant electrochemical active area, significant ORR catalytic activity and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and together with the description are used to explain the principles of the present invention. Other embodiments and many expected advantages of the embodiments will be readily appreciated as they become better understood by reference to the following detailed description.

[0023] Figure 1 The microscopic morphology of the palladium-lead alloy nanoproduct in Example 1 of the present invention, wherein (a) is a low-magnification transmission electron microscope (TEM) image, and (b) is a high-magnification transmission electron microscope (HRTEM) image;

[0024] Figure 2 HAADF-STEM and Mapping images of the palladium-lead alloy nanoproduct in Example 1 of the present invention;

[0025] Figure 3 This is the EDS spectrum of the palladium-lead alloy nanoproduct in Example 1 of the present invention;

[0026] Figure 4 is the XRD spectrum of the palladium-lead alloy nano product in Example 1 of the present invention;

[0027] Figure 5 This is a low-magnification transmission electron microscope (TEM) image of the palladium-lead alloy nanoproduct in Comparative Example 1 of the present invention;

[0028] Figure 6 This is a low-magnification transmission electron microscope (TEM) image of the palladium-lead alloy nanoproduct in Comparative Example 2 of the present invention;

[0029] Figure 7 This is a low-magnification transmission electron microscope (TEM) image of the palladium-lead alloy nanoproduct in Comparative Example 3 of the present invention;

[0030] Figure 8 This is a low-magnification transmission electron microscope (TEM) image of the palladium-lead alloy nanoproduct in Comparative Example 4 of the present invention;

[0031] Fig. 9 The inductively coupled plasma mass spectrometry (ICP-MS) analysis diagram of the palladium-lead alloy nano-products of Comparative Examples 1 to 4 and Example 1 of the present invention;

[0032] Fig.10 The microscopic morphology of the Pd nanosheets without adding the Pb precursor salt in Comparative Example 5 of the present invention, wherein (a) and (b) are low-magnification transmission electron microscope (TEM) images;

[0033] Fig.11 is Pd in ​​Example 1 of the present invention 3 CO removal cyclic voltammograms of Pb NWs / C, Pd NSs / C in Comparative Example 5, commercial Pd / C and Pt / C;

[0034] Fig.12 is Pd in ​​Example 1 of the present invention 3 ORR performance test results of Pb NWs / C, Pd NSs / C in Comparative Example 5, commercial Pd / C and Pt / C, where (a) is a linear voltammetric curve; (b) is a bar graph of mass activity and area activity;

[0035] Fig.13 is Pd in ​​Example 1 of the present invention 3 Comparison of the ORR performance stability of Pb NWs / C and Pt / C measured by chronoamperometry under constant voltage conditions. DETAILED DESCRIPTION

[0036] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] The present invention provides a method for preparing palladium-lead alloy nanowires, comprising the following steps:

[0039] 1) Place palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten, polyvinyl pyrrolidone-55000 and ethanol in a 20 mL polytetrafluoroethylene liner, mix them evenly, and stir them at room temperature for 20 to 40 minutes, wherein ethanol is used as a reaction solvent, polyvinyl pyrrolidone is used as a surfactant, hexadecyltrimethylammonium chloride is used as a coordination agent, hexacarbonyl tungsten is used as a reducing agent, palladium acetylacetonate is used as a palladium source, lead chloride is used as a lead source, and the ratio of palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten, polyvinyl pyrrolidone-55000 and ethanol is 9 to 11 mg: 9 to 11 mg: 20 to 30 mg: 20 to 30 mg: 90 to 110 mg: 11 to 13 mL, wherein the purity of ethanol is above 99.7%.

[0040] 2) Take out the stirring magnet in the solution obtained in step 1, and place the liner in the stainless steel jacket, compact and tighten it, and then put it into a programmable temperature-controlled oven. After 40 to 50 minutes, the oven temperature is increased to 170 to 190° C. and maintained for 80 to 100 minutes, and then naturally cooled to room temperature.

[0041] 3) The solution obtained in step 2 is washed several times with ethanol-water, collected by centrifugation to obtain palladium-lead alloy nanowires, and stored in an ethanol solution, wherein the concentration of the noble metal is about 1 mg / mL Pd .

[0042] The embodiments of the present application also provide a palladium-lead alloy nanowire, which is manufactured using the above-mentioned method for preparing the palladium-lead alloy nanowire.

[0043] The present invention also provides a method for preparing a palladium-lead alloy nanowire catalyst, comprising the above-mentioned method for preparing the palladium-lead alloy nanowire, and preparing the palladium-lead alloy nanowire at a concentration of 15-25% by weight. Pd The amount of the catalyst is loaded on superconducting activated carbon to prepare a palladium-lead alloy nanowire catalyst. The palladium-lead alloy nanowire catalyst can be used as a cathode electrocatalyst for fuel cells.

[0044] The embodiments of the present application also provide a palladium-lead alloy nanowire catalyst, which is prepared by the preparation method of the palladium-lead alloy nanowire catalyst.

[0045] The following is further explained by specific examples and comparative examples.

[0046] Example 1

[0047] Add 10 mg of acetylacetonate palladium, 10 mg of lead chloride, 25 mg of hexadecyltrimethylammonium chloride, 25 mg of hexacarbonyl tungsten, 100 mg of polyvinylpyrrolidone-55000 and 12 mL of ethanol to 20 mL of tetrafluoroethylene liner and mix well. Stir at room temperature for 30 minutes. Then take out the stirring magnet and put the liner in the stainless steel jacket. After compacting and tightening, put it in a programmable temperature-controlled oven. After 45 minutes, the oven temperature rises from room temperature to 180 ° C and maintains for 90 minutes, and then cools naturally to room temperature. Then wash with ethanol-water several times, collect by centrifugation to obtain the palladium-lead alloy nanoproduct and store it in an ethanol solution, in which the concentration of precious metals is about 1 mg / mL Pd .

[0048] Figure 1 This is a microscopic morphology of the palladium-lead alloy nanoproduct of Example 1 of the present application. The palladium-lead alloy nanoproduct prepared under the conditions of Example 1 is wavy and linear, that is, palladium-lead alloy nanowires, and has a high degree of dispersibility and uniform morphology, and the yield is close to 100%. At the same time, this sample has abundant twist nodes, which are often a symbol of lattice distortion and are often accompanied by the generation of defects, and their diameter size ranges from 6 to 10 nm.

[0049] Figure 2 This is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image and element distribution (Mapping) map of the palladium-lead alloy nanowires of Example 1 of the present application. The palladium-lead alloy nanowires prepared under the conditions of Example 1 were characterized to further determine the distribution and composition of each element in the wavy nanowires, and the uniform distribution of Pb and Pd atoms in the sample.

[0050] Figure 3 This is the energy dispersive X-ray spectrometer (EDS) spectrum of the palladium-lead alloy nanowires of Example 1 of the present application. The distribution of each element of the palladium-lead alloy nanowires prepared under the conditions of Example 1 is uniform, and the EDS test results show that the ratio between Pd and Pb atoms is close to 3:1.

[0051] Figure 4 It is a spectrum that uses a powder X-ray diffractometer to characterize the physical structure. The data is analyzed by Jade 6.5 and it is known that obvious diffraction peaks appear at about 38.78°, 45.06°, 65.50°, and 78.88°, which mainly correspond to the 111, 200, 220, and 311 diffraction planes of Pd (PdJCPDS46-1043) with a face-centered cubic structure, and are consistent with the lattice spacing information shown in the high-resolution electron microscope image. In addition, the XRD of the prepared palladium-lead alloy nanowires has only one set of diffraction peaks, indicating that the crystal form of the prepared palladium-lead alloy nanowires is a face-centered cubic structure.

[0052] Comparative Example 1

[0053] Add 10 mg of acetylacetonate palladium, 10 mg of lead chloride, 25 mg of hexadecyltrimethylammonium chloride, 25 mg of hexacarbonyl tungsten, 100 mg of polyvinylpyrrolidone-55000 and 12 mL of ethanol to 20 mL of tetrafluoroethylene liner, mix well, stir at room temperature for 30 minutes, then take out the stirring magnet and put the liner in the stainless steel jacket, compact and tighten it, put it in a programmable temperature-controlled oven, and raise the oven temperature to 100 ° C after 45 minutes, and then cool it naturally to room temperature. Then wash it with ethanol-water several times, collect it by centrifugation to obtain the palladium-lead alloy nanoproduct and store it in an ethanol solution, in which the concentration of the precious metal is about 1 mg / mL Pd .

[0054] Figure 5 This is a microscopic morphology picture of the palladium-lead alloy nanoproduct of comparative example 1 of the present application. The palladium-lead alloy nanoproduct grown under the conditions of comparative example 1 is in the form of flakes, i.e., palladium-lead alloy nanosheets, which have a very different morphology from the sample prepared in example 1 of the present application, indicating that structural regulation plays a decisive role in the morphology of the sample of example 1, and structural regulation can be achieved by adjusting the growth temperature of the palladium-lead alloy nanoproduct.

[0055] Comparative Example 2

[0056] Add 10 mg of acetylacetonate palladium, 10 mg of lead chloride, 25 mg of hexadecyltrimethylammonium chloride, 25 mg of hexacarbonyl tungsten, 100 mg of polyvinylpyrrolidone-55000 and 12 mL of ethanol to 20 mL of tetrafluoroethylene liner and mix well. Stir at room temperature for 30 minutes. Then take out the stirring magnet and put the liner in the stainless steel jacket. After compacting and tightening, put it in a programmable temperature-controlled oven. After 45 minutes, the oven temperature rises to 140 ° C, and then cools naturally to room temperature. Then wash with ethanol-water several times, collect by centrifugation to obtain the palladium-lead alloy nanoproduct and store it in an ethanol solution, in which the concentration of precious metals is about 1 mg / mL Pd .

[0057] Figure 6 This is a microscopic morphology diagram of the palladium-lead alloy nanoproduct of Comparative Example 2 of the present application. On the basis of Comparative Example 1, the growth temperature of the palladium-lead alloy nanoproduct is further increased to regulate the structure of the palladium-lead alloy nanoproduct. The {111} surface (top / bottom) balance of the palladium-lead alloy nanoproduct grown under the conditions of Comparative Example 2 is broken, and etching occurs, resulting in broken nanowires indicated by the arrows in the figure, which have a very different morphology from Example 1 of the present application, indicating that structural regulation plays a dominant role in the sample morphology of Example 1.

[0058] Comparative Example 3

[0059] Add 10 mg of acetylacetonate palladium, 10 mg of lead chloride, 25 mg of hexadecyltrimethylammonium chloride, 25 mg of hexacarbonyl tungsten, 100 mg of polyvinylpyrrolidone-55000 and 12 mL of ethanol to 20 mL of tetrafluoroethylene liner, mix well, stir at room temperature for 30 minutes, then take out the stirring magnet and put the liner in the stainless steel jacket, compact and tighten it, put it in a programmable temperature-controlled oven, and raise the oven temperature to 180°C after 45 minutes, and then cool it naturally to room temperature. Then wash it several times with ethanol-water, collect it by centrifugation to obtain the palladium-lead alloy nanoproduct and store it in an ethanol solution, in which the concentration of the precious metal is about 1 mg / mL Pd .

[0060] Figure 7 This is a microscopic morphology of the palladium-lead alloy nano product of Comparative Example 3 of the present application. On the basis of Comparative Example 2, the growth temperature of the palladium-lead alloy nano product is further increased, and the structure of the palladium-lead alloy nano product is regulated. The palladium-lead alloy nano crystals grown under the conditions of Comparative Example 3 present nano crystals with broken edge structures. This is because the etching phenomenon becomes more and more serious, causing the ultra-thin nano sheet structure to be etched into a broken edge structure, and thus obtaining a nano particle morphology that is different from that of Example 1 of the present application.

[0061] Comparative Example 4

[0062] In a 20mL tetrafluoroethylene liner, add 10mg of acetylacetonate palladium, 10mg of lead chloride, 25mg of hexadecyltrimethylammonium chloride, 25mg of hexacarbonyl tungsten, 100mg of polyvinylpyrrolidone-55000 and 12mL of ethanol and mix evenly, stir at room temperature for 30min, then take out the stirring magnet and put the liner in the stainless steel jacket, compact and tighten it, put it in a programmable temperature-controlled oven, and the oven temperature rises to 180℃ for 45min and maintains for 30min, then cools naturally to room temperature. Then wash with ethanol-water several times, collect by centrifugation to obtain the palladium-lead alloy nanoproduct and store it in an ethanol solution, in which the concentration of the precious metal is about 1mg / mL Pd .

[0063] Figure 8 This is a microscopic morphology of the palladium-nickel alloy nanosheet of comparative example 4 of the present application. On the basis of comparative example 3, the growth time of the palladium-lead alloy nanoproduct is extended, and the structure of the palladium-lead alloy nanoproduct is regulated. The palladium-lead alloy nanoproduct grown under the conditions of comparative example 4 has a morphology similar to that of the product of Example 1 of the present application. This is because the kinetics and thermodynamics of the entire reaction system gradually tend to a new equilibrium under this condition, and the nanoparticles begin to undergo oriented connection or atomic attachment growth, and finally form this palladium-lead alloy nanowire structure with rich kink sites.

[0064] Fig. 9The inductively coupled plasma mass spectrometry (ICP-MS) analysis diagram of the palladium-nickel alloy nanoproducts of Comparative Examples 1 to 4 and Example 1 of the present application. Combined with the analysis of its microscopic morphology, in Comparative Examples 1 to 4 and Example 1, as Pb in the product is further reduced, the palladium-lead alloy nanowire structure with rich kink sites is gradually generated, indicating that structural regulation plays a decisive role in the morphology of the nanowires.

[0065] Comparative Example 5

[0066] In a 20mL tetrafluoroethylene liner, add 10mg of acetylacetonate palladium, 25mg of hexadecyltrimethylammonium chloride, 25mg of hexacarbonyl tungsten, 100mg of polyvinylpyrrolidone-55000 and 12mL of ethanol and mix evenly. Stir at room temperature for 30 minutes, then take out the stirring magnet and put the liner in the stainless steel jacket, compact and tighten it, and put it in a programmable temperature-controlled oven. After 45 minutes, the oven temperature rises to 180°C and maintains for 90 minutes, then cools naturally to room temperature. Then wash with ethanol-water several times, collect the palladium nanocrystals by centrifugation and store them in an ethanol solution, in which the concentration of the precious metal is about 1mg / mL Pd .

[0067] Fig.10 This is a microscopic morphology of the palladium nanosheet of Comparative Example 5 of the present application. The palladium nanocrystals grown under the conditions of Comparative Example 5 mainly present a nanosheet structure. Due to the lack of lead chloride, the original structural control design is destroyed, resulting in a difference in morphology from the product of Example 1 of the present application.

[0068] The palladium-lead alloy nanowires synthesized in Example 1 of the present application and the palladium nanosheets synthesized in Comparative Example 5 were loaded on activated carbon at a mass fraction of 20% to prepare a palladium-lead alloy nanowire catalyst (Pd 3 Pb NWs / C) and palladium nanosheet catalysts (Pd NSs / C) were prepared and subjected to relevant electrochemical tests.

[0069] Specifically, the glassy carbon electrode is repeatedly polished on a polishing cloth until a mirror-like glassy carbon electrode surface is obtained; 1 to 3 μg of noble metal palladium-lead alloy nanowire catalyst dispersion droplets are applied on a 0.196 cm 2 On the glassy carbon electrode of the rotating disk, preferably, 2 μg of the noble metal palladium-lead alloy nanowire catalyst dispersion is evenly coated on the surface of the glassy carbon electrode; after the palladium-lead alloy nanowire catalyst is dried, the glassy carbon electrode (Pd 3 Pb NWs / C was used as the working electrode and saturated calomel (Hg / Hg 2 Cl 2, saturated KCl) electrode and mercury / mercury oxide (Hg / HgO, 0.1M KOH) electrode were used as reference electrodes in acidic and alkaline systems, respectively, and platinum mesh or carbon rod was used as counter electrode to detect the electrocatalytic oxygen reduction performance of the catalyst. Before the electrochemical test, the glassware used was soaked in piranha solution, washed repeatedly with ultrapure water for more than 3 to 5 times after being taken out, and then rinsed with the freshly prepared electrolyte to be tested for more than 2 to 4 times to reduce the influence of impurities on the electrochemical test results.

[0070] Fig.11 Based on N 2 Saturated 0.1M HClO 4 In the solution, the -1 The scan rate records Pd 3 Cyclic voltammetry curves of Pb NWs / C, Pd NSs / C, Pd / C and Pt / C catalysts with a single layer of CO adsorbed on their surfaces. Specifically, a glassy carbon electrode coated with a Pd-Pb alloy nanowire catalyst was placed in 0.1 M HClO 4 solution electrolyte, and N 2 To saturation or pass CO to saturation. First, pre-scan the working electrode, and after the CV curve is stable, place the working electrode in the electrolyte saturated with CO for 20 minutes, and then perform cyclic voltammetry on the electrode again, with a scan range of -0.25 to 1.2 V (vs. SCE) and a scan rate of 20 mV·s -1 , and obtain the CO removal curve. By calculating the desorbed CO monolayer charge (420 μC·cm -2 ) was used to evaluate the specific activity area (ECSA) of these catalysts. 3 The electrochemical active area of ​​Pb NWs / C electrocatalyst is the largest, with a value of 87.4 m 2 ·g -1 .

[0071] Fig.12 It is Pd 3 Pb NWs / C, Pd NSs / C, Pd / C and Pt / C electrocatalysts in O 2 ORR polarization curve (LSV) in saturated 0.1 M KOH at a scan rate of 10 mV·s -1 , the RDE speed was 1600 rpm, the test temperature was room temperature, and the LSV current density was normalized by the electrode area. 3 Pb NWs / C has the best mass activity and area activity among these electrocatalysts, with a value of 2.26 A·mg -1 Pd and 2.59 mA cm -2, which are 13.3 and 10.8 times of commercial Pt / C respectively.

[0072] Fig.13 Display Pd 3 Pb NWs / C and commercial Pt / C were tested at 0.4 V (V vs. RHE) for 12 h. 3 The ORR relative current density of Pb NWs / C showed a slight decrease of 5.1%, while that of Pt / C decreased by 27.5%. Compared with the drastic decrease of Pt / C, the palladium-lead alloy nanowire catalyst has good ORR stability.

[0073] The above describes the specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing palladium-lead alloy nanowires, It is characterized in that The following steps are involved: 1) Add palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten and polyvinylpyrrolidone-55000 to ethanol, and stir at room temperature until the mixture is uniformly mixed. The ratio of palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten, polyvinylpyrrolidone-55000 and ethanol in step 1 is 9-11 mg: 9-11 mg: 20-30 mg: 20-30 mg: 90-110 mg: 11-13 mL, wherein the purity of ethanol is above 99.7%; 2) The solution obtained in step 1 is heated from room temperature to 170-190° C. over 40-50 min and maintained at 170-190° C. for 80-100 min, and then cooled naturally to room temperature; 3) The solution obtained in step 2 is washed and collected by centrifugation to obtain palladium-lead alloy nanowires, which are then stored in an ethanol solution.

2. The method for preparing palladium-lead alloy nanowires according to claim 1, It is characterized in that The temperature of the solution obtained in step 1 was raised from room temperature to 180° C. over 45 min and maintained for 90 min, and then naturally cooled to room temperature.

3. The method for preparing palladium-lead alloy nanowires according to claim 1, It is characterized in that The ratio of the palladium acetylacetonate, lead chloride, hexadecyltrimethylammonium chloride, hexacarbonyl tungsten, polyvinylpyrrolidone-55000 and ethanol in step 1 is 10 mg: 10 mg: 25 mg: 25 mg: 100 mg: 12 mL, wherein the purity of ethanol is above 99.7%.

4. A palladium-lead alloy nanowire, It is characterized in that The palladium-lead alloy nanowires are prepared by the preparation method of any one of claims 1 to 3.

5. The palladium-lead alloy nanowire according to claim 4, It is characterized in that The lead alloy nanowire has a face-centered cubic structure and a diameter range of 6 to 10 nm.

6. A method for preparing a palladium-lead alloy nanowire catalyst, It is characterized in that The method for preparing palladium-lead alloy nanowires according to any one of claims 1 to 3 further comprises: preparing the palladium-lead alloy nanowires at a concentration of 15 to 25% wt Pd The loading amount was loaded on superconducting activated carbon to prepare palladium-lead alloy nanowire catalyst.

7. The method for preparing the palladium-lead alloy nanowire catalyst according to claim 6, It is characterized in that The palladium-lead alloy nanowires are prepared at 20% wt Pd The loading amount was loaded on superconducting activated carbon to prepare palladium-lead alloy nanowire catalyst.

8. A palladium-lead alloy nanowire catalyst, It is characterized in that The palladium-lead alloy nanowire catalyst is prepared by the preparation method of claim 6 or 7.

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