An oxygen electrode catalyst resistant to air impurity poisoning, and a method for preparing and using the same

Abstract

The application provides an oxygen electrode catalyst resistant to air impurity poisoning and a preparation method and application thereof, and belongs to the technical field of electrode materials. The carbon-supported Pt alloy catalyst is prepared first, Ni and / or Co is used to form an alloy with Pt, and the oxygen reduction performance of the catalyst is improved. The carbon-supported Pt alloy catalyst is prepared into a working electrode, and is activated by cyclic voltammetry electrochemical treatment, so that the oxygen reduction performance of Pt is improved. The electrode loaded with the activated catalyst is first immersed in an acid solution of Ru salt, and after being cleaned, constant potential treatment is carried out in an acid solution, so that Ru is uniformly modified on the surface of the electrode loaded with the activated catalyst, the adsorption sites and adsorption energy of air impurities on the catalyst surface are coordinately controlled, and the catalyst has the effect of being resistant to air impurity poisoning.

Description

Technical Field

[0001] This invention relates to the field of electrode materials technology, and in particular to an oxygen electrode catalyst resistant to air poisoning, its preparation method, and its application. Background Technology

[0002] Oxygen electrodes are gaseous electrodes widely used in fuel cells, metal-air batteries, water electrolysis, and hydrogen peroxide generators. In practical applications, air is typically supplied directly to the oxygen electrode instead of O2 using a compressor, reducing system complexity and saving costs. However, commonly used oxygen electrode catalysts are Pt / C catalysts. Air contains numerous poisoning species, such as SO2, SO3, NO2, NO, H2S, CO, CO2, O3, small organic molecules (formic acid, methanol, ethanol, propylene, acetonitrile, methyl methacrylate, naphthalene, and acetylene, etc.), and metal ions. These impurities strongly interact with the Pt / C catalyst, occupying the oxygen electrode surface and affecting its performance, leading to a decline in performance and lifespan. Therefore, researching oxygen electrode catalysts resistant to air poisoning is crucial for promoting the large-scale commercial application of oxygen electrodes.

[0003] Current research indicates that introducing other metals into Pt / C catalysts and alloying them with Pt to adjust the electronic structure of Pt can improve the catalyst's tolerance to air impurities. However, studies show that the adsorption behavior of air impurities and O2 is simultaneously affected by the electronic structure of Pt. With the addition of other metals (such as Co, Ni, and Ru), the air impurity tolerance and oxygen reduction performance of Pt / C catalysts are usually mutually restrictive, making it impossible to simultaneously meet commercial requirements. For example, alloying Ru with Pt improves the air impurity tolerance of Pt / C catalysts, but it still cannot achieve complete anti-poisoning. The high-potential oxidation regeneration process after poisoning accelerates the aging of the Pt / C catalyst.

[0004] Therefore, how to prepare an oxygen electrode catalyst with high oxygen reduction activity and excellent resistance to air impurity poisoning is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] The purpose of this invention is to provide an oxygen electrode catalyst with high oxygen reduction activity and excellent resistance to air impurity poisoning, as well as its preparation method and application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0008] (1) A soluble Pt salt, a soluble doped metal salt and a solvent are mixed to obtain an alloy precursor solution;

[0009] The alloy precursor solution was subjected to a hydrothermal reaction to obtain an alloy dispersion.

[0010] The alloy dispersion was mixed with a carbon support and dried to obtain a carbon-supported Pt alloy catalyst.

[0011] The soluble doped metal salt is a soluble salt of Ni and / or a soluble salt of Co.

[0012] (2) The carbon-supported Pt alloy catalyst obtained in step (1) is mixed with ultrapure water, isopropanol and binder to obtain a catalyst slurry; the catalyst slurry is coated on the electrode to obtain a working electrode;

[0013] The working electrode was subjected to cyclic voltammetric electrochemical treatment to obtain an electrode supported on an activated catalyst;

[0014] (3) The electrode with the activated catalyst obtained in step (2) is immersed in an acid solution of Ru salt, and then cleaned to obtain a Ru salt pretreated electrode.

[0015] The Ru-pretreated electrode was subjected to constant potential treatment in an acidic solution to obtain an oxygen electrode catalyst resistant to air poisoning.

[0016] Preferably, in step (1), the concentration of Pt salt in the alloy precursor solution is 1~100 mmol / L; and the concentration of soluble doped metal salt in the alloy precursor solution is 2~200 mmol / L.

[0017] Preferably, the temperature of the hydrothermal reaction in step (1) is 50~200℃; the time of the hydrothermal reaction is 12~60h.

[0018] Preferably, in step (1), the mass percentage of Pt in the soluble Pt salt is 5-50% of the mass percentage of the carbon support.

[0019] Preferably, the concentration of carbon-supported Pt alloy catalyst in the catalyst slurry in step (2) is 0.1~10 mg / mL.

[0020] Preferably, in step (2), the low potential of the cyclic voltammetric electrochemical treatment is -1 to 0.8 V; the high potential is 0.8 to 1.5 V; the scan rate is 5 to 500 mV / s; and the number of scan cycles is 2 to 100.

[0021] Preferably, in step (3), the concentration of Ru in the acid solution of Ru salt is 1~20 mmol / L; and the concentration of acid in the acid solution of Ru salt is 0.001~10 mol / L.

[0022] Preferably, the potential for constant potential treatment in step (3) is 0.05~1V; the time for constant potential treatment is 1s~2min.

[0023] The present invention also provides an oxygen electrode catalyst resistant to air impurity poisoning prepared by the preparation method described above, comprising a carbon support and a catalyst supported on the carbon support;

[0024] The catalyst comprises a Ru-surface-modified Pt alloy;

[0025] The Pt alloy is an alloy of Pt and a doped metal;

[0026] The doped metal is Ni and / or Co.

[0027] The present invention also provides the application of the oxygen electrode catalyst resistant to air impurity poisoning described in the above technical solution in the oxygen electrode of fuel cells, metal-air batteries, water electrolysis or hydrogen peroxide generators.

[0028] This invention provides a method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps: mixing a soluble Pt salt, a soluble doped metal salt, and a solvent to obtain an alloy precursor solution; subjecting the alloy precursor solution to a hydrothermal reaction to obtain an alloy dispersion; mixing the alloy dispersion with a carbon support and drying to obtain a carbon-supported Pt alloy catalyst; wherein the soluble doped metal salt is a soluble salt of Ni and / or a soluble salt of Co; mixing the carbon-supported Pt alloy catalyst with ultrapure water, isopropanol, and a binder to obtain a catalyst slurry; coating the catalyst slurry onto an electrode to obtain a working electrode; subjecting the working electrode to cyclic voltammetric electrochemical treatment to obtain an electrode with a supported activated catalyst; immersing the electrode with the supported activated catalyst in an acidic solution of Ru salt, removing it, and washing it to obtain a Ru salt pretreated electrode; and subjecting the Ru salt pretreated electrode to a constant potential treatment in an acidic solution to obtain an oxygen electrode catalyst resistant to air poisoning. This invention first prepares a carbon-supported Pt alloy catalyst, utilizing Ni and / or Co to form an alloy with Pt, which can modify the electronic structure of Pt and improve the oxygen reduction performance of the catalyst. The carbon-supported Pt alloy catalyst is then used as a working electrode. Cyclic voltammetric electrochemical treatment is employed to activate the carbon-supported Pt alloy catalyst supported on the working electrode. During this process, residual organic matter in the carbon-supported Pt alloy catalyst is removed, exposing a clean Pt surface. Simultaneously, Ni and / or Co on the surface of the carbon-supported Pt alloy catalyst dissolve, resulting in a Pt-rich layer on the surface and an alloy of Ni and / or Co with Pt inside. The Ni and / or Co in the inner layer exert an electronic effect on the surface Pt, thereby enhancing the oxygen reduction performance of Pt. This invention involves first immersing the electrode with the supported activated catalyst in an acidic solution of Ru salt, ensuring the Ru salt solution is distributed throughout the electrode. After cleaning, a constant potential treatment is performed in an acidic solution, enabling control over the uniform modification of Ru onto the surface of the electrode. The Ru surface modification coordinates and controls the adsorption sites and adsorption energies of air impurities on the catalyst surface, resulting in complete resistance to air impurity poisoning. Results from the examples show that, compared to commercial Pt / C, the catalyst prepared in this invention exhibits significantly improved air impurity tolerance without reducing oxygen reduction activity, achieving complete resistance to poisoning. This balance between oxygen reduction activity and resistance to air impurity poisoning is beneficial for the large-scale commercial application of oxygen electrodes. Attached Figure Description

[0029] Figure 1 The XRD diffraction pattern of the PtNi / C alloy catalyst prepared in Example 1 of this invention;

[0030] Figure 2 The oxygen reduction curves of the Ru-PtNi / C alloy catalyst prepared in Example 1 of this invention before and after SO2 poisoning are shown.

[0031] Figure 3 TEM image of the Ru-PtCo / C alloy catalyst prepared in Example 2 of this invention;

[0032] Figure 4 Oxygen reduction curves of the Ru-PtCo / C alloy catalyst prepared in Example 2 of this invention before and after being poisoned by a mixed gas of 0.5 mmol / L NO and 0.5 mol / L NO2;

[0033] Figure 5 The EDS spectrum of the Ru-PtNi / C alloy catalyst prepared in Example 3 of this invention;

[0034] Figure 6 The oxygen reduction curves of the Ru-PtNi / C alloy catalyst prepared in Example 3 of this invention before and after being poisoned by 10 mg / L O3;

[0035] Figure 7 Oxygen reduction curves of the Ru-PtCo / C alloy catalyst prepared in Example 4 of this invention before and after being poisoned by a mixed gas of 0.5 mmol / L SO2 and 0.5 mmol / L NO2;

[0036] Figure 8 The cyclic voltammetry curves of the Ru-PtCo / C alloy catalyst prepared in Example 4 of this invention before and after aging test are shown.

[0037] Figure 9 The oxygen reduction curves of the commercial Pt / C used in Comparative Example 1 of this invention before and after being poisoned by 0.5 mmol / L SO2. Detailed Implementation

[0038] This invention provides a method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0039] (1) A soluble Pt salt, a soluble doped metal salt and a solvent are mixed to obtain an alloy precursor solution;

[0040] The alloy precursor solution was subjected to a hydrothermal reaction to obtain an alloy dispersion.

[0041] The alloy dispersion was mixed with a carbon support and dried to obtain a carbon-supported Pt alloy catalyst.

[0042] The soluble doped metal salt is a soluble salt of Ni and / or a soluble salt of Co.

[0043] (2) The carbon-supported Pt alloy catalyst obtained in step (1) is mixed with ultrapure water, isopropanol and binder to obtain a catalyst slurry; the catalyst slurry is coated on the electrode to obtain a working electrode;

[0044] The working electrode was subjected to cyclic voltammetric electrochemical treatment to obtain an electrode supported on an activated catalyst;

[0045] (3) The electrode with the activated catalyst obtained in step (2) is immersed in an acid solution of Ru salt, and then cleaned to obtain a Ru salt pretreated electrode.

[0046] The Ru-pretreated electrode was subjected to constant potential treatment in an acidic solution to obtain an oxygen electrode catalyst resistant to air poisoning.

[0047] This invention involves mixing a soluble Pt salt, a soluble doped metal salt, and a solvent to obtain an alloy precursor solution.

[0048] In this invention, the soluble Pt salt is preferably an organometallic compound containing Pt or a soluble Pt salt, more preferably including one or more of platinum acetylacetonate, platinum olefin complex, chloroplatinic acid and platinum nitrate.

[0049] In this invention, the soluble doped metal salt is a soluble salt of Ni and / or a soluble salt of Co. Preferably, the soluble salt of Ni comprises a Ni-containing organometallic compound or a soluble Ni salt, more preferably one or more of nickel acetylacetonate, nickel chloride, and nickel acetate. Preferably, the soluble salt of Co comprises a Co-containing organometallic compound or a soluble Co salt, more preferably one or more of cobalt acetylacetonate, cobalt nitrate, cobalt carbonyl, Co-EDTA complex, and cobalt citrate complex.

[0050] In this invention, the solvent preferably includes N,N-dimethylformamide or isopropanol.

[0051] The present invention does not impose any particular limitation on the method of mixing the soluble Pt salt, the soluble doped metal salt and the solvent, as long as the soluble Pt salt and the soluble doped metal salt can be completely dissolved in the solvent.

[0052] The present invention does not have a special limitation on the amount of solvent used. It can be adjusted according to the amount of soluble Pt salt and soluble doped metal salt used, so that the concentration of Pt salt and soluble doped metal salt in the alloy precursor solution can reach the required range.

[0053] In this invention, the concentration of Pt salt in the alloy precursor solution is preferably 1~100 mmol / L. As one embodiment of this invention, the concentration of Pt salt in the alloy precursor solution can be 1 mmol / L, 5 mmol / L, 10 mmol / L, 15 mmol / L, 20 mmol / L, 25 mmol / L, 30 mmol / L, 35 mmol / L, 40 mmol / L, 45 mmol / L, 50 mmol / L, 55 mmol / L, 60 mmol / L, 65 mmol / L, 70 mmol / L, 75 mmol / L, 80 mmol / L, 85 mmol / L, 90 mmol / L, 95 mmol / L, or 100 mmol / L.

[0054] In this invention, the concentration of the soluble doped metal salt in the alloy precursor solution is preferably 2-200 mmol / L. As one embodiment of this invention, the concentration of the soluble doped metal salt in the alloy precursor solution can be 2 mmol / L, 5 mmol / L, 10 mmol / L, 15 mmol / L, 20 mmol / L, 25 mmol / L, 30 mmol / L, 35 mmol / L, 40 mmol / L, 45 mmol / L, 50 mmol / L, 55 mmol / L, 60 mmol / L, 65 mmol / L, 70 mmol / L, 75 mmol / L, 80 mmol / L, 85 mmol / L, 90 mmol / L, 9... 5mmol / L, 100mmol / L, 105mmol / L, 110mmol / L, 115mmol / L, 120mmol / L, 125mmol / L, 130mmol / L, 135mmol / L, 140mmol / L, 145mmo l / L, 150mmol / L, 155mmol / L, 160mmol / L, 165mmol / L, 170mmol / L, 180mmol / L, 185mmol / L, 190mmol / L, 195mmol / L or 200mmol / L.

[0055] After obtaining the alloy precursor solution, the present invention performs a hydrothermal reaction on the alloy precursor solution to obtain an alloy dispersion.

[0056] In this invention, the preferred temperature for the hydrothermal reaction is 50-200°C; the preferred time for the hydrothermal reaction is 12-60 hours. As one embodiment of this invention, the temperature for the hydrothermal reaction can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C; the preferred time for the hydrothermal reaction can be 12 hours, 15 hours, 20 hours, 24 hours, 30 hours, 36 hours, 40 hours, 48 ​​hours, 54 hours, or 60 hours. By conducting the hydrothermal reaction at the above temperatures and times, this invention enables Pt and doped metals in the alloy precursor solution to form alloy nanoparticles. Under the above hydrothermal conditions, the preferred particle size of the alloy nanoparticles in the resulting alloy dispersion is 3-50 nm, more preferably 5-9 nm. The alloy nanoparticles synthesized in this invention have a small particle size, which results in a large number of active sites when used as catalysts, thus giving the prepared catalysts excellent activity.

[0057] After obtaining the alloy dispersion, the present invention mixes the alloy dispersion with a carbon support and dries it to obtain a carbon-supported Pt alloy catalyst.

[0058] In this invention, the carbon carrier is preferably toner. In embodiments of this invention, the toner can be Vulcan XC-72 toner or BP2000 toner.

[0059] In this invention, the mass percentage of Pt in the soluble Pt salt relative to the carbon support is preferably 5-50%. In this invention, the mass percentage of Pt in the soluble Pt salt relative to the carbon support is simply referred to as the platinum loading. As one embodiment of this invention, the platinum loading can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. By controlling the platinum loading within the above range, this invention can improve the activity of the catalyst.

[0060] The present invention does not specifically limit the method of mixing the alloy dispersion with the carbon support, as long as the alloy dispersion is sufficiently dispersed in the carbon support. In embodiments of the present invention, the mixing method can be stirring, and the stirring time can be 12 hours.

[0061] The present invention preferably involves first performing solid-liquid separation and washing on the system obtained by mixing the alloy dispersion with the carbon support to obtain particles, and then drying the particles to obtain a carbon-supported Pt alloy catalyst.

[0062] In an embodiment of the present invention, the solid-liquid separation method may be centrifugation.

[0063] In embodiments of the present invention, the washing reagent may be ethanol or high-purity water. In embodiments of the present invention, the washing method may be washing three times with ethanol, followed by washing three times with high-purity water.

[0064] In this invention, the drying process is preferably freeze-drying. In an embodiment of this invention, the freeze-drying temperature can be -50°C; and the freeze-drying time can be 12 hours.

[0065] After obtaining the carbon-supported Pt alloy catalyst, the present invention mixes the carbon-supported Pt alloy catalyst with ultrapure water, isopropanol and binder to obtain a catalyst slurry.

[0066] In this invention, the adhesive is preferably a Nafion solution. In this invention, the concentration of the Nafion aqueous solution is preferably 1-10%. In embodiments of this invention, the concentration of the Nafion solution can be 5%.

[0067] In this invention, the volume ratio of ultrapure water, isopropanol and binder is preferably (6~12) mL: (2~4) mL: (8~16) μL, more preferably 9 mL: 3 mL: 12 μL, 6 mL: 2 mL: 8 μL or 12 mL: 4 mL: 16 μL.

[0068] In this invention, the concentration of the carbon-supported Pt alloy catalyst in the catalyst slurry is preferably 0.1~10 mg / mL. As one embodiment of this invention, the concentration of the carbon-supported Pt alloy catalyst in the catalyst slurry can be 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, or 10 mg / mL. By controlling the concentration of the carbon-supported Pt alloy catalyst in the catalyst slurry within the above range, this invention is more conducive to forming a catalyst slurry layer of uniform thickness on the electrode.

[0069] After obtaining the catalyst slurry, the present invention coats the catalyst slurry onto the electrode to obtain the working electrode.

[0070] In this invention, the electrode is preferably a glassy carbon electrode.

[0071] In this invention, the coating method is preferably a rotary air-drying method. This invention forms a uniform coating on the electrode using a rotary air-drying method. In this invention, the rotational speed of the rotary air-drying method is preferably 100~1000 r / min, more preferably 500~1000 r / min.

[0072] In this invention, the amount of catalyst coated on the working electrode is preferably 10~300 μg / cm³. 2More preferably 100~200 μg / cm 2 .

[0073] Preferably, the working electrode is obtained by drying after coating. The present invention does not specifically limit the drying method, as long as it can evaporate the solvent in the catalyst slurry. In embodiments of the present invention, the drying method can be rotary drying.

[0074] After obtaining the working electrode, the present invention performs cyclic voltammetric electrochemical treatment on the working electrode to obtain an electrode supported on an activated catalyst.

[0075] In this invention, the cyclic voltammetric electrochemical treatment method is preferably performed using an electrochemical workstation. In embodiments of this invention, the electrolyte for the cyclic voltammetric electrochemical treatment can be an HClO4 solution or an H2SO4 solution; the concentration of the HClO4 solution can be 0.1~0.2 mol / L, and the concentration of the H2SO4 solution can be 0.05 mol / L; the counter electrode for the cyclic voltammetric electrochemical treatment can be a platinum wire, and the reference electrode can be a reversible hydrogen electrode (RHE). In this invention, the low potential for the cyclic voltammetric electrochemical treatment is preferably -1~0.8V, more preferably 0.5V; the high potential is preferably 0.8~1.5V, more preferably 1V; the scan rate is preferably 5~500mV / s, more preferably 100~300mV / s; and the number of scan cycles is preferably 2~100, more preferably 10~50. This invention removes organic matter from the working electrode surface through cyclic voltammetric electrochemical treatment, exposing the Pt surface. The Ni or Co on the surface is dissolved, resulting in a clean Pt-rich layer on the catalyst surface. The inner Ni layer exhibits an electronic effect on the surface platinum, thereby improving the oxygen reduction performance of the catalyst.

[0076] After obtaining the electrode with the supported activated catalyst, the present invention impregnates the electrode with the supported activated catalyst in an acidic solution of Ru salt, and then cleans it to obtain a Ru salt pretreated electrode.

[0077] In this invention, the concentration of Ru in the acidic solution of the Ru salt is preferably 1-20 mmol / L. As one embodiment of this invention, the concentration of Ru in the acidic solution of the Ru salt can be 1 mmol / L, 2 mmol / L, 5 mmol / L, 10 mmol / L, 15 mmol / L, or 20 mmol / L.

[0078] In this invention, the acid in the Ru salt acid solution is preferably HClO4. The concentration of the acid in the Ru salt acid solution is preferably 0.001~10 mol / L. As one embodiment of this invention, the concentration of the acid in the Ru salt acid solution can be 0.001 mmol / L, 0.1 mmol / L, 1 mmol / L, 2 mmol / L, 5 mmol / L, or 10 mmol / L. This invention, by impregnating the electrode with the supported activated catalyst in the Ru salt acid solution, enables Ru ions to be distributed on the surface of the electrode with the supported activated catalyst.

[0079] In this invention, the immersion treatment time is preferably 3s to 5min, more preferably 10s to 1min.

[0080] In this invention, the cleaning reagent is preferably ultrapure water. This invention removes excess Ru salt from the electrode surface supporting the activated catalyst through cleaning.

[0081] After obtaining the Ru-pretreated electrode, the present invention performs constant potential treatment on the Ru-pretreated electrode in an acidic solution to obtain an oxygen electrode catalyst resistant to air impurity poisoning.

[0082] In this invention, the acidic solution is preferably an HClO4 solution. The concentration of the acidic solution is preferably 0.001~10 mol / L. As one embodiment of this invention, the concentration of the acidic solution can be 0.001 mmol / L, 0.1 mmol / L, 1 mmol / L, 2 mmol / L, 5 mmol / L, or 10 mmol / L. This invention uses an acidic solution as the electrolyte.

[0083] In embodiments of the present invention, the working electrode for the constant potential treatment can be an electrode pretreated with Ru salt; the counter electrode can be a platinum wire; and the reference electrode can be a reversible hydrogen electrode.

[0084] In this invention, the potential for the constant potential treatment is preferably 0.05~1V, more preferably 0.5~0.7V. The duration of the constant potential treatment is preferably 1s~2min, more preferably 5s~20s. This invention enables Ru to uniformly modify the surface of Pt through constant potential treatment.

[0085] The method provided by this invention first prepares a carbon-supported Pt alloy catalyst, using Ni and / or Co to form an alloy with Pt, modifying the electronic structure of Pt and improving the oxygen reduction performance of the catalyst. The carbon-supported Pt alloy catalyst is then used to prepare a working electrode, which is activated by cyclic voltammetric electrochemical treatment, further enhancing the oxygen reduction performance. In this invention, the electrode with the activated catalyst is first immersed in an acidic solution of Ru salt, ensuring the Ru salt solution is distributed throughout the electrode. After cleaning, it undergoes constant potential treatment in an acidic solution, enabling control over the uniform modification of Ru on the surface of the electrode. Surface modification with Ru can coordinate and control the adsorption sites and adsorption energies of air impurities on the catalyst surface, making the catalyst completely resistant to poisoning by air impurities.

[0086] The present invention also provides an oxygen electrode catalyst resistant to air impurity poisoning prepared by the preparation method described above, comprising a carbon support and a catalyst supported on the carbon support.

[0087] In this invention, the catalyst comprises a Ru-surface-modified Pt alloy. In this invention, the Pt alloy is an alloy of Pt and a doped metal. In this invention, the doped metal is Ni and / or Co.

[0088] In this invention, the particle size of the Pt and doped metal alloy is preferably 3~50 nm, more preferably 5~9 nm.

[0089] In this invention, the mass percentage of the catalyst in the oxygen electrode catalyst for resisting air impurity poisoning is preferably 1-80%, more preferably 10-30%.

[0090] The present invention also provides the application of the oxygen electrode catalyst resistant to air impurity poisoning described in the above technical solution as an oxygen electrode in a fuel cell, a metal-air battery, a water electrolyzer, or a hydrogen peroxide generator.

[0091] The present invention does not have any particular limitation on the method of using the oxygen electrode catalyst resistant to air impurity poisoning as the oxygen electrode of fuel cells, metal-air batteries, water electrolysis or hydrogen peroxide generators; any conventional method of oxygen electrode application can be used.

[0092] The oxygen electrode catalyst prepared in this invention has excellent anti-poisoning effect against air impurities such as SO2, NO, NO2, and O3. Therefore, it can be used as an oxygen electrode in fuel cells, metal-air batteries, water electrolysis, or hydrogen peroxide generators, thereby improving the stability of the oxygen electrode.

[0093] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0094] Example 1

[0095] A method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0096] (1) Mix 32 mg of bis(acetylacetone)platinum(II) and 54 mg of nickel acetylacetone with 20 mL of N,N-dimethylformamide to obtain a blue-green alloy precursor solution;

[0097] The alloy precursor solution was transferred to a 50 mL reaction vessel, sealed, and placed in a homogeneous reactor. The solvothermal temperature was set at 145 °C, and the reaction time was 42 h. After the temperature of the reaction vessel dropped to room temperature, the solution inside the reaction vessel was transferred to a beaker to obtain an alloy dispersion.

[0098] The alloy dispersion was mixed with 50 mg of Vulcan XC-72 carbon powder, added to a rotor, and mixed and stirred for 24 h before centrifugation. The solid obtained by centrifugation was washed with ethanol and ultrapure water three times in sequence, and then freeze-dried at -50 °C for 12 h to obtain carbon-supported Pt alloy catalyst.

[0099] (2) 12 mg of the carbon-supported Pt alloy catalyst obtained in step (1) is ultrasonicated with 9 mL of ultrapure water, 3 mL of isopropanol and 12 μL of Nafion solution for 15 min to obtain a catalyst slurry; 10 μL of the catalyst slurry is coated on the surface of a glassy carbon electrode and dried by rotation to obtain a working electrode.

[0100] The working electrode was transferred to an electrolytic cell and electrochemically processed using an electrochemical workstation. The electrolyte was 0.1 mol / L HClO4, the counter electrode was a platinum wire, and the reference electrode was a reversible hydrogen electrode. Cyclic voltammetry was performed on the working electrode with an initial potential of 0.5 V, a scan range of 0.05–1 V, a scan rate of 100 mV / s, and 10 scan cycles to obtain the electrode with the activated catalyst supported, denoted as the PtNi / C alloy catalyst.

[0101] (3) The electrode with the activated catalyst obtained in step (2) is immersed in a solution of 0.1 mol / L HClO4 and 10 mmol / L RuCl3 for 10 s. After taking it out, the electrode surface is washed with ultrapure water to obtain the Ru salt pretreated electrode.

[0102] The Ru-pretreated electrode was transferred to an electrolytic cell and electrochemically treated using an electrochemical workstation. The electrolyte was 0.1 mol / L HClO4, the counter electrode was a platinum wire, the reference electrode was a reversible hydrogen electrode, and the potential was kept constant at 0.7 V for 5 s to obtain an oxygen electrode catalyst resistant to air poisoning (denoted as Ru-PtNi / C alloy catalyst).

[0103] Figure 1 The image shows the XRD diffraction pattern of the PtNi / C alloy catalyst prepared in Example 1. Figure 1 It can be seen that the PtNi / C alloy catalyst prepared in Example 1 has the characteristics of a PtNi alloy.

[0104] Test Example 1

[0105] The catalytic performance of the Ru-PtNi / C alloy catalyst prepared in Example 1 before and after poisoning was tested using a linear voltammetric scan. The oxygen reduction curves of the PtNi / C alloy catalyst prepared in Example 1 before and after SO2 poisoning are shown below. Figure 2 As shown. From Figure 2 As can be seen, the ORR curves did not change before and after poisoning, indicating that the catalyst is completely resistant to SO2 poisoning. Furthermore, the oxygen reduction mass activity of the catalyst is 0.37 A / mgPt, which is superior to the commercial Pt / C shown in Comparative Example 1.

[0106] Example 2

[0107] A method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0108] (1) Mix 32 mg of bis(acetylacetone)platinum(II) and 60 mg of cobalt acetylacetone with 20 mL of N,N-dimethylformamide to obtain an alloy precursor solution;

[0109] The alloy precursor solution was transferred to a 50 mL reaction vessel, sealed, and placed in a homogeneous reactor. The solvothermal temperature was set at 130 °C, and the reaction time was 42 h. After the temperature of the reaction vessel dropped to room temperature, the solution inside the reaction vessel was transferred to a beaker to obtain an alloy dispersion.

[0110] The alloy dispersion was mixed with 80 mg of BP-2000 carbon powder, added to a rotor, and stirred for 12 h before centrifugation. The solid obtained by centrifugation was washed with ethanol and ultrapure water three times in sequence, and then freeze-dried at -50℃ for 12 h to obtain carbon-supported Pt alloy catalyst.

[0111] (2) 8 mg of the carbon-supported Pt alloy catalyst obtained in step (1) was ultrasonicated with 6 mL of ultrapure water, 2 mL of isopropanol and 8 μL of Nafion solution for 10 min to obtain a catalyst slurry; 15 μL of the catalyst slurry was coated on the surface of a glassy carbon electrode and dried by rotation to obtain a working electrode.

[0112] The working electrode was transferred to an electrolytic cell and electrochemically processed using an electrochemical workstation. The electrolyte was 0.2 mol / L HClO4, the counter electrode was a platinum wire, and the reference electrode was a reversible hydrogen electrode. Cyclic voltammetry was performed on the working electrode with an initial potential of 0.7 V, a scan range of 0.05–1 V, a scan rate of 50 mV / s, and 5 scan cycles to obtain the electrode with the activated catalyst supported.

[0113] (3) The electrode with the activated catalyst obtained in step (2) is immersed in a solution of 0.2 mol / L HClO4 and 6 mmol / L RuCl3 for 10 s. After taking it out, the electrode surface is washed with ultrapure water to obtain the Ru salt pretreated electrode.

[0114] The Ru-pretreated electrode was transferred to an electrolytic cell and electrochemically treated using an electrochemical workstation. The electrolyte was 0.2 mol / L HClO4, the counter electrode was a platinum wire, the reference electrode was a reversible hydrogen electrode, and the constant potential was 0.4 V for 10 s to obtain an oxygen electrode catalyst resistant to air poisoning (denoted as Ru-PtCo / C alloy catalyst).

[0115] Figure 3 This is a TEM image of the Ru-PtCo / C alloy catalyst prepared in Example 2. Figure 3 It can be seen that the Ru-PtCo / C alloy catalyst prepared in Example 2 is uniformly dispersed on the carbon support.

[0116] Test Example 2

[0117] The catalytic performance of the Ru-PtCo / C alloy catalyst prepared in Example 2 before and after poisoning was tested using linear voltammetry. The oxygen reduction curves of the Ru-PtCo / C alloy catalyst prepared in Example 2 before and after poisoning by a mixture of 0.5 mmol / L NO and 0.5 mol / L NO2 gas are shown below. Figure 4 As shown. From Figure 4 It can be seen that the oxygen reduction curves did not change before and after poisoning, indicating that the catalyst is completely resistant to NO and NO2 poisoning. Furthermore, the oxygen reduction mass activity of the catalyst at 0.9V is 0.34A / mgPt, which is superior to the commercial Pt / C shown in Comparative Example 1.

[0118] Example 3

[0119] A method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0120] (1) Mix 50 mg of chloroplatinic acid, 60 mg of nickel chloride and 50 mL of ethanol to obtain an alloy precursor solution;

[0121] The alloy precursor solution was transferred to a 50 mL reaction vessel, sealed, and placed in a homogeneous reactor. The solvothermal temperature was set at 150 °C, and the reaction time was 24 h. After the temperature of the reaction vessel dropped to room temperature, the solution inside the reaction vessel was transferred to a beaker to obtain an alloy dispersion.

[0122] The alloy dispersion was mixed with 100 mg of Vulcan XC-72 carbon powder, added to a rotor, and mixed and stirred for 24 h before centrifugation. The solid obtained by centrifugation was washed with ethanol and ultrapure water three times in sequence, and then freeze-dried at -50 °C for 12 h to obtain carbon-supported Pt alloy catalyst.

[0123] (2) 16 mg of the carbon-supported Pt alloy catalyst obtained in step (1) is ultrasonicated with 12 mL of ultrapure water, 4 mL of isopropanol and 16 μL of Nafion solution for 20 min to obtain a catalyst slurry; 10 μL of the catalyst slurry is coated on the surface of a glassy carbon electrode and dried by rotation to obtain a working electrode.

[0124] The working electrode was transferred to an electrolytic cell and electrochemically processed using an electrochemical workstation. The electrolyte was 0.1 mol / L HClO4, the counter electrode was a platinum wire, and the reference electrode was a reversible hydrogen electrode. Cyclic voltammetry was performed on the working electrode with an initial potential of 0.1 V, a scan range of 0.05–1 V, a scan rate of 50 mV / s, and 3 scan cycles to obtain the electrode with the activated catalyst supported.

[0125] (3) The electrode with the activated catalyst obtained in step (2) is immersed in a solution of 0.1 mol / L HClO4 and 8 mmol / L RuCl3 for 20 s. After taking it out, the electrode surface is washed with ultrapure water to obtain the Ru salt pretreated electrode.

[0126] The Ru-pretreated electrode was transferred to an electrolytic cell and electrochemically treated using an electrochemical workstation. The electrolyte was 0.1 mol / L HClO4, the counter electrode was a platinum wire, the reference electrode was a reversible hydrogen electrode, and the potential was kept constant at 0.6 V for 2 s to obtain an oxygen electrode catalyst resistant to air poisoning (denoted as Ru-PtNi / C alloy catalyst).

[0127] Figure 5 The EDS spectrum of the Ru-PtNi / C alloy catalyst prepared in Example 3 is shown below. Figure 5A faint Ru signal can be observed, indicating that a small amount of Ru has been loaded onto the catalyst.

[0128] Test Example 3

[0129] The catalytic performance of the Ru-PtNi / C alloy catalyst prepared in Example 3 before and after poisoning was tested using linear voltammetry. The oxygen reduction curves of the Ru-PtNi / C alloy catalyst prepared in Example 3 before and after poisoning with 10 mg / L O3 are shown below. Figure 6 As shown. From Figure 6 As can be seen, the curves did not change before and after poisoning, indicating that the catalyst is completely resistant to O3 poisoning. Furthermore, the oxygen reduction mass activity of the catalyst at 0.9V is 0.5A / mgPt, which is superior to the commercial Pt / C shown in Comparative Example 1.

[0130] Example 4

[0131] A method for preparing an oxygen electrode catalyst resistant to air poisoning, comprising the following steps:

[0132] (1) Mix 30 mg of bis(acetylacetone)platinum(II) and 40 mg of cobalt acetylacetone with 50 mL of isopropanol and stir for 10 min to obtain an alloy precursor solution;

[0133] The alloy precursor solution was transferred to a 50 mL reaction vessel, sealed, and placed in a homogeneous reactor. The solvothermal temperature was set at 150 °C, and the reaction time was 30 h. After the temperature of the reaction vessel dropped to room temperature, the solution inside the reaction vessel was transferred to a beaker to obtain an alloy dispersion.

[0134] The alloy dispersion was mixed with 60 mg of BP2000 carbon powder, added to a rotor, and mixed and stirred for 24 h. After centrifugation, the solid obtained by centrifugation was washed with ethanol and ultrapure water three times in sequence, and then freeze-dried at -50℃ for 10 h to obtain carbon-supported Pt alloy catalyst.

[0135] (2) 12 mg of the carbon-supported Pt alloy catalyst obtained in step (1) was ultrasonicated with 9 mL of ultrapure water, 3 mL of isopropanol and 12 μL of Nafion solution for 15 min to obtain a catalyst slurry; 20 μL of the catalyst slurry was coated on the surface of a glassy carbon electrode and dried by rotation to obtain a working electrode.

[0136] The working electrode was transferred to an electrolytic cell and electrochemically processed using an electrochemical workstation. The electrolyte was 0.05 mol / L H₂SO₄, the counter electrode was a platinum wire, and the reference electrode was a reversible hydrogen electrode. Cyclic voltammetry was performed on the working electrode with an initial potential of 0.5 V, a scan range of 0–1.2 V, a scan rate of 100 mV / s, and 20 scan cycles to obtain the electrode with the activated catalyst supported.

[0137] (3) The electrode with the activated catalyst obtained in step (2) is immersed in a solution of 0.05 mol / L H2SO4 and 5 mmol / L RuCl3 for 20 s. After taking it out, the electrode surface is washed with ultrapure water to obtain the Ru salt pretreated electrode.

[0138] The Ru-pretreated electrode was transferred to an electrolytic cell and electrochemically treated using an electrochemical workstation. The electrolyte was 0.05 mol / L H₂SO₄, the counter electrode was a platinum wire, the reference electrode was an Ag / AgCl electrode, and the electrode was kept at a constant potential of 0.5 V for 1 min to obtain an oxygen electrode catalyst resistant to air poisoning (denoted as Ru-PtCo / C alloy catalyst).

[0139] Test Example 4

[0140] The catalytic performance of the Ru-PtCo / C alloy catalyst prepared in Example 4 before and after poisoning was tested using linear voltammetry. The oxygen reduction curves of the Ru-PtCo / C alloy catalyst prepared in Example 4 before and after poisoning by a mixed gas of 0.5 mmol / L SO2 and 0.5 mmol / L NO2 are shown below. Figure 7 As shown. From Figure 7 It can be seen that the ORR curves did not change before and after poisoning, indicating that the catalyst is completely resistant to poisoning by the SO2 and NO2 mixed gas. Furthermore, the oxygen reduction mass activity of the catalyst at 0.9V is 0.42A / mgPt, which is superior to the commercial Pt / C shown in Comparative Example 1.

[0141] Figure 8 The cyclic voltammetry curves of the Ru-PtCo / C alloy catalyst prepared in Example 4 before and after aging test are shown. After 4000 cycles of cyclic voltammetry scanning, the curves showed no significant changes, indicating that the active area did not decrease and the catalyst has good stability.

[0142] Comparative Example 1

[0143] The comparative example uses commercial Pt / C from JM Company, with a Pt load of 20%.

[0144] Test Example 5

[0145] Figure 9 The oxygen reduction curves are those of the commercial Pt / C used in Comparative Example 1 before and after poisoning with 0.5 mmol / L SO2. (Compared to those in Example 1.) Figure 2 Compared to the oxygen reduction curve of the catalyst of this invention, the oxygen reduction activity of commercial Pt / C at 0.9V is only 0.25 A / mgPt, significantly lower than the 0.37 A / mgPt of the catalyst of this invention in Example 1. After poisoning, the oxygen reduction activity of the Pt / C catalyst decreased to 0.09 A / mgPt, a loss of 64%. In Example 1... Figure 2 The oxygen reduction curve of the catalyst of this invention remained unchanged after poisoning, demonstrating complete resistance to poisoning by air impurities. This indicates that compared to commercial Pt / C, the catalyst of this invention exhibits superior oxygen reduction activity and can completely resist poisoning by air impurities.

[0146] The results above show that the oxygen electrode catalyst prepared by this invention exhibits high oxygen reduction activity and excellent resistance to air poisoning. This is because the catalyst prepared by this invention includes a Pt alloy catalyst, which modifies the electronic structure of Pt to improve the oxygen reduction performance of the catalyst. Surface modification with Ru coordinates and controls the adsorption sites and adsorption energies of air impurities on the catalyst surface, making the catalyst completely resistant to air poisoning. Compared with commercial Pt / C, the catalyst prepared by this invention significantly improves air impurity tolerance without reducing oxygen reduction activity, achieving complete resistance to poisoning. This balance between oxygen reduction activity and air impurity resistance is beneficial for the large-scale commercial application of oxygen electrodes.

[0147] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an oxygen electrode catalyst resistant to air poisoning, characterized in that, Includes the following steps: (1) A soluble Pt salt, a soluble doped metal salt and a solvent are mixed to obtain an alloy precursor solution; The alloy precursor solution was subjected to a hydrothermal reaction to obtain an alloy dispersion. The alloy dispersion was mixed with a carbon support and dried to obtain a carbon-supported Pt alloy catalyst. The soluble doped metal salt is a soluble salt of Ni and / or a soluble salt of Co. (2) The carbon-supported Pt alloy catalyst obtained in step (1) is mixed with ultrapure water, isopropanol and binder to obtain a catalyst slurry; the catalyst slurry is coated on the electrode to obtain a working electrode; The working electrode was subjected to cyclic voltammetric electrochemical treatment to obtain an electrode supported on an activated catalyst; (3) The electrode with the activated catalyst obtained in step (2) is immersed in an acid solution of Ru salt, and then cleaned to obtain a Ru salt pretreated electrode. The Ru-pretreated electrode was subjected to constant potential treatment in an acidic solution to obtain an oxygen electrode catalyst resistant to air poisoning.

2. The preparation method according to claim 1, characterized in that, In step (1), the concentration of Pt salt in the alloy precursor solution is 1~100 mmol / L; the concentration of soluble doped metal salt in the alloy precursor solution is 2~200 mmol / L.

3. The preparation method according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step (1) is 50~200℃; the time of the hydrothermal reaction is 12~60h.

4. The preparation method according to claim 1, characterized in that, In step (1), the mass percentage of Pt in the soluble Pt salt is 5-50% of the mass of the carbon support.

5. The preparation method according to claim 1, characterized in that, In step (2), the concentration of carbon-supported Pt alloy catalyst in the catalyst slurry is 0.1~10 mg / mL.

6. The preparation method according to claim 1, characterized in that, In step (2), the low potential of the cyclic voltammetric electrochemical treatment is -1 to 0.8 V; the high potential is 0.8 to 1.5 V; the scan rate is 5 to 500 mV / s; and the number of scan cycles is 2 to 100.

7. The preparation method according to claim 1, characterized in that, In step (3), the concentration of Ru in the acid solution of Ru salt is 1~20 mmol / L; the concentration of acid in the acid solution of Ru salt is 0.001~10 mol / L.

8. The preparation method according to claim 1, characterized in that, The potential for constant potential treatment in step (3) is 0.05~1V; the time for constant potential treatment is 1s~2min.

9. The oxygen electrode catalyst resistant to air poisoning prepared by the preparation method according to any one of claims 1 to 8, characterized in that, Includes a carbon support and a catalyst supported on the carbon support; The catalyst comprises a Ru-surface-modified Pt alloy; The Pt alloy is an alloy of Pt and a doped metal; The doped metal is Ni and / or Co.

10. The application of the oxygen electrode catalyst resistant to air impurity poisoning as described in claim 9 in the oxygen electrode of a fuel cell, a metal-air battery, a water electrolyzer, or a hydrogen peroxide generator.

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