Surface gold-doped platinum-based catalyst, preparation method thereof and application

Abstract

The present invention provides a platinum-based catalyst with surface gold doping, a preparation method thereof and an application thereof, relating to the technical fields of catalyst preparation and application. This method first prepares a platinum-based nanoparticle catalyst by the impregnation calcination reduction method, then regulates the lattice strain through ligand mediation, and finally induces the discharge of transition metals on the surface of the nanoparticles by the method of inducing transition metal discharge to achieve surface gold doping, obtaining a platinum-based electrocatalyst with surface gold doping. While regulating the lattice strain through ligand mediation, the present invention induces the discharge of transition metals to replace the transition metals with gold, purifies the surface, reduces the dissolution of platinum through the interaction between gold and platinum unsaturated coordination sites, and can also induce the discharge of transition metals to remove the transition metals on the surface of the catalyst. The two act synergistically. While the strain induces the dispersion of Au, the surface strain generated by the ligand can inhibit the surface migration of Au atoms, promote their atomic-level dispersion, and improve the catalytic activity.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation and application, and particularly relates to a platinum-based catalyst with surface gold doping, a preparation method thereof, and an application thereof. Background Art

[0002] As an efficient and environmentally friendly energy conversion device, fuel cells have attracted wide attention due to their high energy conversion efficiency and pollution-free properties. In fuel cells, the oxygen reduction reaction (ORR) is the key cathodic reaction, and its reaction rate is slow, requiring an efficient electrocatalyst to lower the reaction energy barrier and accelerate the reaction.

[0003] Platinum-based catalysts are widely used in the oxygen reduction reaction due to their excellent catalytic performance. However, platinum resources are scarce and costly, which limits their large-scale application. To reduce the platinum usage and improve the performance of the catalyst, researchers have been committed to developing new platinum-based alloy catalysts. Platinum is considered a potential oxygen reduction electrocatalyst due to its unique electronic structure and good catalytic performance. However, in the acidic working environment of fuel cells, the transition metals on the surface of platinum-based will dissolve, resulting in the attenuation of catalyst performance and the damage of the proton exchange membrane.

[0004] To overcome this problem, researchers have tried to improve the properties of platinum-based intermetallic compounds through surface modification means. For example, Chinese Patent Application CN202410799854.4 discloses a preparation method of a catalyst for fuel cells assisted by nitrogen-containing organic small molecules. After the noble metal transition metal alloy is formed, a nitrogen-containing organic liquid is mixed with the catalyst, and a carbon shell coating can be formed through simple sintering, thereby avoiding the migration of alloy particles and alleviating the precipitation of metal ions, which helps to overcome the problem of weak stability of current platinum-based alloy catalysts. However, the external carbon shell is easily damaged during the use of the catalyst, and the carbon shell will affect the mass transfer of reactants and thus reduce the catalytic performance.

[0005] Chinese Patent Application CN202410760180.7 discloses a tellurium-doped platinum-cobalt intermetallic compound catalyst. The doping of tellurium not only effectively reduces the size of nanoparticles and increases their dispersion, but also can effectively alleviate the dissolution of cobalt and inhibit the agglomeration and growth of nanoparticles during the stability test. However, the doping of tellurium exists not only on the surface of nanoparticles but also inside, which leads to a large amount of tellurium usage and causes waste of resources. Summary of the Invention

[0006] Aiming at the defects of the above-mentioned existing technologies, the purpose of the present invention is to provide a preparation method of a surface gold-doped platinum-based catalyst, which utilizes the selective adsorption of ligands on the surface of transition metals to induce lattice compressive strain. The strain effect causes the Pt-Au bond length to contract during subsequent gold doping, optimizes the position of the d-band center, and enhances the adsorption regulation ability for oxygen-containing intermediates. At the same time, this method can use trace amounts of gold to induce the discharge of transition metals on the surface of nanoparticles, replace the transition metals with gold by inducing the discharge of transition metals, purify the surface, and reduce the dissolution of platinum through the interaction between gold and platinum unsaturated coordination sites. The synergistic effect of the two can induce the dispersion of Au while the surface strain generated by the ligand can inhibit the surface migration of Au atoms and promote their atomic-level dispersion. At the same time, strain sites (such as step edges) preferentially anchor Au atoms to form Pt-transition metal-Au three-atom active sites.

[0007] The half-wave potential of the surface gold-doped platinum-based catalyst prepared by this method exceeds that of the commercial Pt / C catalyst by 49 mV and exceeds that of the gold-free doped platinum-based catalyst by 30 mV. Its mass activity reaches 0.87 A mg Pt -1 , and at the same time has excellent stability, and the mass activity only decreases by 22.9% after 10,000 potential cycles.

[0008] To achieve the above object, the present invention provides a preparation method of a surface gold-doped platinum-based catalyst, which includes the following steps:

[0009] S1, adding a platinum precursor, a transition metal precursor, and carbon black into a dispersant for ultrasonic dispersion, then rotary evaporating to dryness, and then grinding evenly;

[0010] S2, calcining the material obtained in step S1 in a reducing atmosphere at a temperature of 800-1000 °C for 0.5-4 h, and then cooling to room temperature with the furnace to obtain a platinum-based catalyst;

[0011] S3, ultrasonically dispersing the material obtained in step S2 in ethanol, adding an ethanol solution of a ligand, stirring at room temperature, then rotary evaporating to dryness, and then grinding evenly;

[0012] S4, ultrasonically dispersing the material obtained in step S3 in water, then adding a gold precursor salt and stirring at room temperature to induce the discharge of transition metals, filtering, washing, and drying to obtain a surface gold-doped platinum-based catalyst.

[0013] Further, in step S3, the ligand is mercaptopropionic acid or polyvinylpyrrolidone, the concentration of the ligand is 0.01-0.1 mM, the volume is 5-10 ml; the stirring speed is 100-600 rpm, the stirring time is 12-24 h, and the rotary evaporation temperature is 80-90 °C.

[0014] Furthermore, in step S4, the mass ratio of the material to the gold precursor salt is 1:(0.2-0.5).

[0015] Furthermore, in step S1, the molar ratio of platinum to transition metal is 1:(0.5~1.5).

[0016] Furthermore, when inducing transition metal discharge, the stirring speed is 100~600 rpm, and the stirring time is 1~6 h.

[0017] Furthermore, in step S1, the sum of the mass of platinum and transition metal in the platinum precursor and transition metal precursor is 40% to 80% of the mass of carbon black.

[0018] Furthermore, the gold precursor salt is one of chloroauric acid, gold chloride, gold(II) chloride, and potassium gold(II) cyanide; the carbon black is one of graphite black, ECP-600, ECP-300, and XC-72; the platinum precursor is one of chloroplatinic acid, potassium chloroplatinate, and potassium chloroplatinate, and the concentration of the platinum precursor is 0.01~0.2 M; the transition metal is cobalt, manganese, iron, copper, nickel, zinc, gallium, molybdenum, and tungsten, and the transition metal precursor is one of phthalocyanine salt, acetate, nitrate, and chloride; the concentration of the transition metal precursor is 0.05~0.2 M.

[0019] The present invention also provides a platinum-based catalyst doped with surface gold, which is prepared by the above-mentioned preparation method. The platinum-based catalyst doped with surface gold is carbon-supported metal nanoparticles, the platinum loading in the catalyst is 15-60wt%; and the particle size of the nanoparticles in the catalyst is 3-7 nm.

[0020] Furthermore, in the surface gold-doped platinum-based catalyst, the atomic fraction of gold is 0.1-5%.

[0021] The aforementioned surface gold-doped platinum-based catalyst can be used as a cathode catalyst for hydrogen fuel cells.

[0022] The beneficial effects of the present invention are:

[0023] 1. The preparation method of the surface gold-doped platinum-based catalyst provided by the present invention first prepares a platinum-based nanoparticle catalyst by the impregnation-calcination-reduction method, then regulates the lattice strain through ligand mediation, impregnates the ligand solution, and finally induces the discharge of transition metals on the nanoparticle surface by the method of inducing transition metal discharge to achieve the surface doping of gold. The surface doping of gold can not only reduce the dissolution of platinum by adjacent to the platinum undercoordinated sites, but also remove the surface transition metals to purify the nanoparticle surface. The two work together. While the strain induces the dispersion of Au, the surface strain generated by the ligand can inhibit the surface migration of Au atoms and promote its atomic-level dispersion. At the same time, the strain sites (such as step edges) preferentially anchor Au atoms to form Pt-transition metal-Au three-atom active sites, thereby maintaining the activity and stability of the catalyst.

[0024] 2. In the prior art, platinum-based nanoparticles are often prone to the dissolution of platinum during the oxygen reduction reaction, resulting in the reduction of catalyst active sites and the decline of performance. In the present invention, by doping gold on the surface of platinum-based nanoparticles, gold atoms can contact the undercoordinated sites of platinum to form stable chemical bonds. This structure can effectively inhibit the formation of platinum surface oxide species, thereby reducing the dissolution of platinum. In addition, during the process of inducing transition metal discharge, the gold salt can induce the discharge of transition metals and replace the transition metals on the nanoparticle surface with gold. This process can not only purify the catalyst surface and reduce surface impurities. The doping of gold can also optimize the electronic structure of the platinum-based catalyst. The introduction of gold atoms can adjust the electronic state of the platinum-based alloy, making it more conducive to the adsorption and activation of oxygen molecules, thereby reducing the activation energy of the oxygen reduction reaction. The optimization of this electronic structure not only improves the activity of the catalyst, but also enables it to efficiently promote the oxygen reduction reaction under lower kinetic conditions. The activity of the catalyst is significantly increased, thereby improving the overall performance of the catalyst.

[0025] 3. The half-wave potential of the surface gold-doped platinum-based catalyst prepared by this method exceeds that of the commercial Pt / C catalyst by 49 mV and exceeds that of the gold-free doped platinum-based by 30 mV. Its mass activity reaches 0.87 A mg Pt -1 -1, and at the same time has excellent stability. The mass activity only decreases by 22.9% after 10,000 potential cycles.

[0026] 4. This method has a high utilization rate of doped gold atoms, and the preparation process is simple, low in cost, good in reproducibility, and has low requirements for equipment, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Comparison diagram of the X-ray diffraction (XRD) standard cards of the catalyst prepared in Example 1 and commercial Pt / C.

[0028] Figure 2 Scanning electron microscope image (SEM) of the catalyst prepared in Example 1 and the EDS mapping element distribution diagram of the corresponding area.

[0029] Figure 3 Transmission electron microscope image (TEM) of the catalyst prepared in Example 1.

[0030] Figure 4 Comparison diagram of the rotating disk electrode polarization curves of the catalysts prepared in Example 1, the control group and the commercial Pt / C catalyst in acidic medium.

[0031] Figure 5 Comparison of the polarization curves and cyclic voltammograms of the catalyst prepared in Example 1 before and after 10,000 potential cycles at 0.6 V - 0.95 V (vs. RHE), and comparison of the mass specific activity and electrochemical specific surface area calculated at a fixed polarization potential of 0.9 V.

[0032] Figure 6 Thermogravimetric (TG) curve of the catalyst prepared in Example 1 under air conditions.

[0033] Figure 7 Comparison diagram of the polarization curves of the catalysts obtained in Examples 1 - 3 and Comparative Examples 1 - 2.

[0034] Figure 8 Comparison diagram of the cyclic voltammograms of the catalysts obtained in Examples 1 - 3 and Comparative Examples 1 - 2.

[0035] Figure 9 Transmission electron microscope image (TEM) of the catalyst obtained in Comparative Example 2.

[0036] Figure 10 Comparison diagram of the polarization curves of the catalysts prepared in Comparative Example 3 and Example 1. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0039] In addition, it should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus.

[0040] In the prior art, during the oxygen reduction reaction process, platinum-based nanoparticles are often prone to platinum dissolution, resulting in a reduction in the active sites of the catalyst and a decline in performance.

[0041] The present invention provides a method for preparing a surface gold-doped platinum-based catalyst. First, a platinum-based nanoparticle catalyst is prepared by an impregnation calcination reduction method, and then the surface transition metal of the nanoparticles is induced to discharge through a method of inducing transition metal discharge to achieve surface doping of gold. The surface doping of gold can not only reduce platinum dissolution by being adjacent to platinum unsaturated coordination sites, but also remove the surface transition metal to purify the nanoparticle surface, thereby maintaining the activity and stability of the catalyst.

[0042] On the one hand, the present invention provides a method for preparing a surface gold-doped platinum-based catalyst, comprising the following steps:

[0043] S1, adding a platinum precursor, a transition metal precursor, and carbon black into a dispersant for ultrasonic dispersion, then rotary evaporating to dryness, and then grinding evenly; wherein, the molar ratio of platinum to transition metal is Pt:Co = 1:(0.5 - 1.5);

[0044] The carbon black is one of graphite carbon black (GCB), ECP-600, ECP-300, and XC-72;

[0045] The platinum precursor is one of chloroplatinic acid, potassium chloroplatinate, and potassium chloroplatite, and the concentration of the platinum precursor is 0.01 - 0.2 M;

[0046] The transition metal precursor is one of phthalocyanine salts, acetates, nitrates, and chlorides; the concentration of the transition metal precursor is 0.05 - 0.2 M. The transition metal is cobalt, manganese, iron, copper, nickel, zinc, gallium, molybdenum, or tungsten.

[0047] Wherein, the sum of the masses of platinum and transition metal in the platinum precursor and the transition metal precursor is 40% - 80% of the mass of the carbon black.

[0048] The dispersant is deionized water, anhydrous ethanol, or acetone;

[0049] During ultrasonic dispersion, the ultrasonic time is 60 min or more; preferably, the ultrasonic dispersion is 60 - 90 min;

[0050] The rotary evaporation temperature is 60 - 100 °C.

[0051] S2. Calcinate the material obtained in step S1 under a reducing atmosphere at a temperature of 800 - 1000 °C for 0.5 - 4 h, and then cool it to room temperature in the furnace to obtain a platinum-based catalyst;

[0052] Among them, the reducing atmosphere is one of hydrogen, hydrogen-argon mixture, and hydrogen-nitrogen mixture.

[0053] Preferably, the calcination temperature is 800 - 900 °C, and the calcination time is 0.5 - 1.5 h.

[0054] S3. Ultrasonically disperse the material obtained in step S2 in ethanol, add an ethanol solution of a ligand, stir at room temperature, then rotary evaporate to dryness, and then grind evenly;

[0055] The ligand is one of mercaptopropionic acid (MPA) or polyvinylpyrrolidone (PVP), with a concentration of 0.01 - 0.1 mM and a volume of 5 - 10 ml.

[0056] The stirring speed is 100 - 600 rpm, the stirring time is 12 - 24 h, the rotary evaporation temperature is (80 - 90) °C, and the rotary evaporation temperature is 60 - 90 °C.

[0057] S4. Ultrasonically disperse the material obtained in step S3 in water, then add a gold precursor salt and stir at room temperature for induced transition metal discharge. After suction filtration and washing, dry it in a vacuum oven to obtain a gold-doped platinum-based catalyst on the surface. Among them, the mass ratio of the material to the gold precursor salt is 1:(0.2 - 0.5).

[0058] The gold precursor salt is one of chloroauric acid, gold chloride, aurous chloride, and potassium aurocyanide.

[0059] During the induced transition metal discharge, the stirring speed is 100 - 600 rpm, and the stirring time is 1 - 6 h.

[0060] The ultrasonic dispersion time is 10 - 30 min; the drying temperature is 60 - 90 °C.

[0061] In the embodiments of the present application, selective adsorption of ligands on the surface of transition metals is utilized to induce lattice compressive strain. The strain effect causes the Pt-Au bond length to contract during subsequent gold doping, optimizes the position of the d-band center, and enhances the ability to regulate the adsorption of oxygen-containing intermediates; a small amount of gold is used to induce the discharge of transition metals on the surface of nanoparticles, and the transition metals are replaced with gold by inducing the discharge of transition metals. While purifying the surface, the interaction between gold and platinum unsaturated coordination sites reduces the dissolution of platinum. Surface doping with gold can not only reduce the dissolution of platinum by being adjacent to platinum unsaturated coordination sites, but also induce the discharge of transition metals to remove the transition metals on the catalyst surface, thereby enhancing the catalytic activity. The two act synergistically. While strain induces the dispersion of Au, the surface strain generated by the ligand can inhibit the surface migration of Au atoms and promote their atomic-level dispersion. At the same time, strain sites (such as step edges) preferentially anchor Au atoms to form Pt-Co-Au three-atom active sites.

[0062] In a second aspect, the present invention also provides a platinum-based catalyst with surface gold doping, which is prepared by the aforementioned preparation method. The platinum-based catalyst with surface gold doping is carbon-supported metal nanoparticles, and the loading amount of platinum in the catalyst is 15-60 wt%; the particle size of the nanoparticles in the catalyst is 3-7 nm.

[0063] In the platinum-based catalyst with surface gold doping, the atomic fraction of gold is 0.1-5%.

[0064] The signal of the gold element was observed in the EDS mapping, indicating the successful doping of gold.

[0065] The aforementioned platinum-based catalyst with surface gold doping can be used as the cathode catalyst of a hydrogen fuel cell.

[0066] The following specifically describes the preparation method of the platinum-based catalyst with surface gold doping provided by the present invention. Unless otherwise specified, the raw materials and reagents in the embodiments of the present application are purchased through commercial channels.

[0067] Example 1

[0068] This example provides a preparation method of a platinum-based catalyst with surface gold doping. First, a platinum-based material is prepared by the impregnation calcination method, and then surface doping with gold is formed by using the method of inducing the discharge of transition metals. The specific steps are as follows:

[0069] (1) Add 25.8 mg of carbon black (acidified graphitized carbon black) to 40 ml of ethanol, then add 8.10 mL (0.01 M) of chloroplatinic acid ethanol solution and 0.81 mL of CoCl2 (0.1 M) ethanol solution to the mixture, and ultrasonically treat for 60 minutes. Next, heat the obtained uniformly mixed solution to 90 °C in a rotary evaporator to dry, collect the obtained powder and grind it evenly.

[0070] (2) Place the powder obtained in step (1) in a tubular furnace, heat it to 800 °C at a heating rate of 10 °C / min under a hydrogen-argon mixed atmosphere, hold it at this temperature for 1 h, and then cool it to room temperature with the furnace to obtain a platinum-based catalyst.

[0071] (3) Add 23 mg of the powder obtained in step (2) to 40 ml of ethanol and ultrasonically treat it for 60 minutes. Then add 7.7 ml of an ethanol solution of mercaptopropionic acid (MPA) (0.05 mM), stir it at room temperature for 15 h, then heat the obtained homogeneous mixed solution to 60 °C in a rotary evaporator to dry it, collect the obtained powder and grind it evenly.

[0072] (4) Add 20 mg of the powder obtained in step (3) to deionized water, ultrasonically treat it for 30 min to form a homogeneous dispersion, then add 8 mg of chloroauric acid, and then stir it at a rotation speed of 400 rpm for 6 h. Then filter it by suction and wash it with deionized water, and dry it in an oven at 70 °C to obtain a platinum-based catalyst with surface gold doping.

[0073] Control group

[0074] The platinum-cobalt catalyst was prepared in the control group; the main difference between the control group and Example 1 is mainly that steps (3) and (4) were not carried out, and the other steps are substantially the same as those in Example 1, which will not be elaborated here.

[0075] Figure 1 It is a comparison chart of the X-ray diffraction (XRD) standard card of the platinum-based catalyst with surface gold doping prepared in Example 1 and commercial Pt / C. It can be seen that the characteristic peaks of (001) and (110) superlattices unique to PtCo appeared near 23° and 33° in the catalyst prepared in Example 1, indicating the formation of a long-range ordered atomic arrangement structure.

[0076] Figure 2 It is the scanning electron microscope image (SEM) of the catalyst prepared in Example 1 and the EDS mapping element distribution chart of the corresponding area. It can be seen the carbon support structure of the catalyst, and no agglomerated metal particles were found, indicating that the particles are evenly loaded on the carbon support and have a small particle size. The results of EDS mapping show that there are three elements, platinum, cobalt, and gold, in the sample, and the element distribution is uniform, indicating that gold has been successfully doped into the surface of the nanoparticles by inducing the discharge of transition metals.

[0077] Figure 3 It is the transmission electron microscope image (TEM) of the catalyst obtained in Example 1. It can be observed that dark-colored nanoparticles are evenly distributed on the carbon support without agglomeration. The particle size of the nanoparticles in the catalyst is 3 - 7 nm.

[0078] Figure 4It is a comparative diagram of the rotating disk polarization curves of the catalysts obtained in Example 1 and the control group and the commercial Pt / C catalyst in an acidic medium. Among them, the electrolyte solution is 0.1 M HClO4 saturated with O2; the scanning rate is 10 mV / s; the scanning voltage range is -0.25 to 0.8 V; the rotation speed is rpm = 1600.

[0079] From the polarization curve after i-R compensation, it can be seen that the half-wave potential of the prepared platinum-based catalyst with surface gold doping exceeds that of the commercial Pt / C catalyst by 49 mV and exceeds that of platinum-cobalt without gold doping by 30 mV.

[0080] Figure 5 It is a comparison of the polarization curves of the catalyst obtained in Example 1 before and after 10,000 potential cycles at a sweep rate of 100 mA / s from 0.6 V to 0.95 V (vs. RHE), and a comparison of the mass-specific activity calculated at a fixed polarization potential of 0.9 V.

[0081] It can be seen that after 10,000 potential cycles, the polarization curve and cyclic voltammogram of the self-made catalyst change very little compared with Pt / C. At the beginning, the mass-specific activity reaches 0.87 A mg Pt -1 , which is 6.7 times that of commercial Pt / C (0.13 A mg Pt -1 ), and the mass-specific activity only decreases by 22.9% after 10,000 potential cycles, which is significantly better than commercial Pt / C, reflecting excellent stability.

[0082] Figure 6 It is the thermogravimetric (TG) curve of the catalyst obtained in Example 1 under air conditions. Starting from 300 °C, due to the oxidation of carbon, a large amount of mass loss occurs, and finally the catalyst loading is 40 wt%.

[0083] Examples 2-3 and Comparative Examples 1-2

[0084] Examples 2-3 and Comparative Examples 1-2 provide a preparation method of a platinum-based catalyst with surface gold doping. Compared with Example 1, the difference is that the mass ratio of the material to the gold precursor salt in step S3 is changed, as shown in the following table; the rest is roughly the same as in Example 1 and will not be elaborated here.

[0085]

[0086] Figure 7 It is a comparative diagram of the polarization curves of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2. Among them, the electrolyte solution is 0.1 M HClO4 saturated with O2; the scanning rate is 10 mV / s; the scanning voltage range is -0.25 to 0.8 V; the rotation speed is rpm = 1600.

[0087] Figure 8 Cyclic voltammetry curve comparison diagram of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2. Among them, electrolyte solution: 0.1 M HClO4 saturated with N2; scanning rate: 50 mV / s; scanning voltage range: 0.05 - 1.1 V.

[0088] It can be seen from the chart that when the mass ratio of the material to the gold precursor salt is less than 1:0.2, due to too little gold doped on the surface, the half-wave potential and active area of the obtained catalyst sample are similar to those of the catalyst sample without gold doping. When the mass ratio of the material to the gold precursor salt is greater than 1:0.5, due to the aggravation of particle aggregation, the half-wave potential and active area of the obtained catalyst sample decrease compared with Examples 1-3.

[0089] Figure 9 Transmission electron microscope image (TEM) of the catalyst obtained in Comparative Example 2. It can be observed that a large amount of aggregation of dark-colored nanoparticles appears on the carbon support.

[0090] Comparative Example 3

[0091] Comparative Example 3 provides a preparation method of a surface gold-doped platinum-based catalyst. Compared with Example 1, the difference is that step (3) is not carried out, and the other steps are substantially the same as those in Example 1, which will not be elaborated here.

[0092] Figure 10 Polarization curve comparison diagram of the catalysts obtained in Example 1 and Comparative Example 3. Among them, electrolyte solution: 0.1 M HClO4 saturated with O2; scanning rate: 10 mV / s; scanning voltage range: -0.25 - 0.8 V; rotation speed: rpm = 1600.

[0093] It can be seen from the figure that the half-wave potential of Example 1 exceeds that of the catalyst prepared in Comparative Example 3 by 29 mV. This is because lattice compression strain will change the atomic spacing of platinum, thereby regulating the position of the d-band center of platinum. Without ligand-mediated lattice strain regulation, no strain is introduced, and the d-band center may be too high or too low, resulting in an imbalance in the adsorption strength of oxygen-containing intermediates (such as O*, OH*, OOH*); the rate-determining step of the oxygen reduction reaction (ORR) (such as O2 dissociation or OH⁻ desorption) has a decreased efficiency due to the mismatch of adsorption energy barriers, resulting in a significant decrease in catalytic activity.

[0094] The synergistic effect is lost, and the inhibition of platinum oxidation and enhancement of corrosion resistance by Au cannot be achieved, accelerating catalyst deactivation and resulting in the deterioration of its comprehensive performance.

[0095] Examples 4-6

[0096] Examples 4-6 provide a method for preparing a surface gold-doped platinum-based catalyst. Compared with Example 1, the difference lies in changing the type of gold precursor salt in step S3, as shown in the following table; the rest is roughly the same as Example 1 and will not be elaborated here.

[0097]

[0098] It can be known from experiments that the surface gold-doped platinum-based catalyst can be successfully prepared in Examples 4-6.

[0099] Example 7

[0100] Example 7 provides a method for preparing a surface gold-doped platinum-based catalyst. Compared with Example 1, the difference lies in replacing 7.7 ml of mercaptopropionic acid in step (3) with 5.1 ml of polyvinylpyrrolidone; the rest is roughly the same as Example 1 and will not be elaborated here.

[0101] Examples 8-15

[0102] Examples 8-15 provide a method for preparing a surface gold-doped platinum-based catalyst. Compared with Example 1, the difference lies in changing the type of transition metal salt in step (1), as shown in the following table; the rest is roughly the same as Example 1 and will not be elaborated here.

[0103]

[0104] It can be known from experiments that the surface gold-doped platinum-based catalyst can be successfully prepared in Examples 8-15.

[0105] It should be noted that the carbon black can also be one of ECP-600, ECP-300, and XC-72. The platinum precursor can also be one of potassium chloroplatinate and potassium chloroplatinate. The transition metal precursor can be one of phthalocyanine transition metal, acetic acid transition metal, and nitric acid transition metal.

[0106] The above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a surface gold-doped platinum-based catalyst, characterized in that: The steps include: S1, adding a platinum precursor, a transition metal precursor and carbon black into a dispersant and ultrasonically dispersing them, then rotary evaporating them to dryness, and then grinding them uniformly; S2, calcining the material obtained in step S1 under a reducing atmosphere at a temperature of 800-1000° C. for a time of 0.5-4 h, and then cooling to room temperature with the furnace to obtain a platinum-based catalyst; S3, ultrasonically dispersing the material obtained in step S2 in ethanol, adding the ethanol solution of the ligand, stirring at room temperature, then rotary evaporating to dryness, and then grinding evenly; the ligand is mercaptopropionic acid or polyvinyl pyrrolidone; S4, ultrasonically dispersing the material obtained in step S3 in water, then adding a gold precursor salt and stirring at room temperature to induce transition metal discharge, filtering, washing and drying to obtain a platinum-based catalyst doped with gold on the surface.

2. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: In step S3, the concentration of the ligand is 0.01-0.1 mM, the volume is 5-10 ml, the stirring speed is 100-600 rpm, the stirring time is 12-24 h, and the rotary evaporation temperature is 80-90°C.

3. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: In step S4, the mass ratio of the material to the gold precursor salt is 1:(0.2-0.5).

4. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: In step S1, the molar ratio of platinum to transition metal is 1:(0.5-1.5).

5. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: When inducing transition metal discharge, the stirring speed is 100 to 600 rpm and the stirring time is 1 to 6 hours.

6. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: In step S1, the mass sum of platinum and transition metal in the platinum precursor and transition metal precursor is 40% to 80% of the mass of carbon black.

7. The method for preparing a surface gold-doped platinum-based catalyst according to claim 1, characterized in that: The gold precursor salt is one of chloroauric acid, gold chloride, gold(II) chloride, and potassium gold(II) cyanide; the carbon black is one of graphite carbon black, ECP-600, ECP-300, and XC-72; the platinum precursor is one of chloroplatinic acid, potassium chloroplatinate, and potassium chloroplatinate, and the concentration of the platinum precursor is 0.01 to 0.2M; the transition metal is cobalt, manganese, iron, copper, nickel, zinc, gallium, molybdenum, and tungsten, and the transition metal precursor is one of phthalocyanine salt, acetate, nitrate, and chloride; the concentration of the transition metal precursor is 0.05 to 0.2M.

8. A platinum-based catalyst doped with gold on the surface, prepared by the method for preparing a platinum-based catalyst doped with gold on the surface according to any one of claims 1 to 7, characterized in that: The platinum-based catalyst doped with gold on the surface is carbon-supported metal nanoparticles, the loading amount of platinum in the catalyst is 15-60wt%; and the particle size of the nanoparticles in the catalyst is 3-7nm.

9. The surface gold-doped platinum-based catalyst according to claim 8, characterized in that: In the platinum-based catalyst doped with gold on the surface, the atomic fraction of gold is 0.1-5%.

10. An application of a platinum-based catalyst doped with gold on the surface, characterized in that: The surface gold-doped platinum-based catalyst is prepared according to the preparation method described in any one of claims 1-7 or is the surface gold-doped platinum-based catalyst described in any one of claims 8-9; the surface gold-doped platinum-based catalyst is used as a cathode catalyst for a hydrogen fuel cell.

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