Preparation method of catalyst, catalyst slurry, membrane electrode and fuel cell
By loading Ir, Ru, and Nb precious metal oxides on the titanium dioxide nanoparticles, forming a catalyst support with high electron conductivity, the problem of fuel cell catalyst support being easily corroded is solved, and the stability and efficiency of the stack are improved.
Patent Information
- Application Number
- CN202411473142.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-03-11
AI Technical Summary
The fuel cell catalyst carrier is easily corroded, resulting in reverse electrode failure, affecting the stability and efficiency of the stack.
The titanium dioxide nanoparticles are loaded with high dispersible Ir, Ru, and Nb precious metal oxides by flame method to form a catalyst support with high electron conductivity to avoid corrosion during the reverse polar phenomenon.
The corrosion resistance and electronic conductivity of the catalyst support are significantly improved, the service life of the fuel cell is extended and its efficiency is improved.
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Figure CN119601689A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of new energy, and in particular to fuel cells. Background Art
[0002] In recent years, the global energy crisis and environmental pollution problems have become increasingly serious, and countries around the world have begun to vigorously develop renewable energy. Among the many renewable energy sources, hydrogen energy has attracted widespread attention due to its high energy density, theoretical reaction product is only water, clean and environmentally friendly, and wide sources. In the current new energy vehicles aimed at solving the problems of global energy consumption and greenhouse gas emissions, fuel cells play a vital role in obtaining electrical energy stored in molecular chemical bonds due to their high efficiency and fuel flexibility. However, the high catalyst cost and poor catalyst durability on fuel cell electrodes have hindered the wider technical deployment of fuel cells. The membrane electrode (MEA) of the proton exchange membrane fuel cell (PEMFC) will reverse polarity in repeated start / shutdown (SU / SD) environments and fuel shortage conditions. Reverse polarity failure is fatal to the stack, mainly due to the corrosion of the carrier and hydrogen deficiency in the Pt / C catalyst. When the fuel cell is running, reverse polarity is prone to occur near the anode outlet. The reason is that the anode outlet is more prone to hydrogen deficiency. Since there is not enough hydrogen to undergo oxidation reaction to release electrons and protons to maintain charge balance, in order to maintain the charge balance of the entire stack system, other substances in the anode catalyst layer (such as water and carbon) will undergo oxidation reaction to produce protons and release electrons, eventually leading to anode reverse polarity. Summary of the invention
[0003] The embodiments of the present application provide a method for preparing a catalyst, a catalyst slurry, a membrane electrode, and a fuel cell to solve the technical problem that the carbon carrier is easily corroded.
[0004] In a first aspect, an embodiment of the present application provides a method for preparing a catalyst, the method for preparing the catalyst comprising the following steps:
[0005] preparing a first dispersion containing titanium dioxide nanoparticles and a noble metal oxide precursor;
[0006] atomizing the first dispersion to form droplets, and introducing the droplets into a diffusion flame via an inert carrier gas;
[0007] filtering the gas flow treated by the diffusion flame through a filter membrane, collecting solids on the filter membrane, and obtaining a catalyst carrier;
[0008] dispersing the catalyst support and the platinum precursor together in a solvent to obtain a second dispersion;
[0009] removing the solvent of the second dispersion, and heating the obtained solid to obtain the catalyst,
[0010] Wherein, the noble metal is at least one of Ir, Ru and Nb.
[0011] In some embodiments of the present application, in the first dispersion, the mass ratio of the noble metal element to the titanium element is 1:5-20; and / or,
[0012] In the first dispersion, the mass percentage of titanium dioxide nanoparticles is 5% to 30%; and / or,
[0013] The solvent of the first dispersion liquid is water.
[0014] In some embodiments of the present application, in the second dispersion, the mass ratio of the catalyst carrier to the platinum element is 1:1.5-20.
[0015] In some embodiments of the present application, the first dispersion is atomized to form droplets, and the atomization rate of the first dispersion is 30 to 100 mL / min.
[0016] In some embodiments of the present application, the flow rate of the inert carrier gas is 4 to 6 L / min.
[0017] In some embodiments of the present application, the diffusion flame is formed by a combustion reaction between methane and oxygen, wherein the flow rate of methane is 1.5 to 2.5 L / min, and the flow rate of oxygen is 3 to 6 L / min.
[0018] In some embodiments of the present application, the noble metal oxide precursor is nitrate.
[0019] In some embodiments of the present application, the platinum precursor is platinum chloride.
[0020] In a second aspect, an embodiment of the present application provides a membrane electrode, wherein the anode catalyst layer of the membrane electrode comprises the catalyst described in any embodiment of the first aspect.
[0021] In a third aspect, an embodiment of the present application provides a fuel cell, wherein the fuel cell comprises the membrane electrode as described in any embodiment of the second aspect.
[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0023] The preparation method of the catalyst provided in the embodiment of the present application uses a flame method to load highly dispersed oxides of Ir, Ru, and Nb precious metals on titanium dioxide nanoparticles, thereby significantly improving the electronic conductivity of titanium dioxide nanoparticles with a small amount of precious metals, and then using the titanium dioxide nanoparticles loaded with precious metals as catalyst carriers. Titanium dioxide has a very high corrosion potential and will not be corroded when the reverse polarity phenomenon occurs, thereby solving the current technical problem that fuel cell catalyst carriers are easily corroded. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0026] Figure 1 A reverse polarization curve diagram of a fuel cell provided in an embodiment of the present application;
[0027] Figure 2 Polarization curve diagram of the fuel cell provided for the embodiments and comparative examples of the present application. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0029] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.
[0030] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0031] Existing fuel cells have the technical problem that the catalyst carbon carrier is easily corroded.
[0032] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:
[0033] In a first aspect, an embodiment of the present application provides a method for preparing a catalyst, the method for preparing the catalyst comprising the following steps:
[0034] S1: preparing a first dispersion containing titanium dioxide nanoparticles and a noble metal oxide precursor;
[0035] S2: atomizing the first dispersion to form droplets, and introducing the droplets into a diffusion flame via an inert carrier gas;
[0036] S3: filtering the airflow treated by the diffusion flame through a filter membrane, collecting solids on the filter membrane, and obtaining a catalyst carrier;
[0037] S4: dispersing the catalyst support and the platinum precursor together in a solvent to obtain a second dispersion;
[0038] S5: removing the solvent of the second dispersion, and heating the obtained solid to obtain the catalyst,
[0039] Wherein, the noble metal is at least one of Ir, Ru and Nb.
[0040] It is easy to understand that the flame aerosol process is a simple and versatile method to synthesize nanostructured particles in the gas phase with high productivity from laboratory to industrial scale, and has the advantages of single-step continuous process, short time consumption, large temperature gradient and high productivity.
[0041] It is easy to understand that titanium dioxide has high chemical stability, so it will not be corroded when the fuel cell is reversed. By treating the first dispersion liquid with a diffusion flame, the noble metal oxide precursor can be decomposed to form a noble metal oxide and loaded onto the surface of titanium dioxide nanoparticles. The oxides of Ir, Ru, and Nb loaded on the surface of titanium dioxide nanoparticles can significantly improve the electronic conductivity of titanium dioxide nanoparticles, thereby improving the problem that titanium dioxide has low electronic conductivity and is not suitable for fuel cell catalyst carriers. The noble metal oxide is loaded onto titanium dioxide by a flame aerosol process. The concentration of the noble metal oxide precursor and the residence time in the high temperature area can be accurately controlled by a flame aerosol process, and the noble metal oxide can form highly dispersed nanoparticles, and the utilization rate of the noble metal oxide deposited on the surface of titanium dioxide increases, which is conducive to reducing the amount of precious metals.
[0042] It is easy to understand that the inert carrier gas can be at least one of nitrogen and argon.
[0043] It is a common technical means in the art to obtain metallic platinum by heating a platinum precursor. As an example, the heating temperature may be 800-1000°C.
[0044] The present application uses a flame method to load highly dispersed oxides of Ir, Ru, and Nb precious metals on titanium dioxide nanoparticles, thereby significantly improving the electronic conductivity of titanium dioxide nanoparticles with a small amount of precious metals. The titanium dioxide nanoparticles loaded with precious metals are then used as catalyst carriers. Titanium dioxide has a very high corrosion potential and will not be corroded when the reverse polarity phenomenon occurs, thereby solving the current technical problem that fuel cell catalyst carriers are easily corroded.
[0045] In some embodiments of the present application, in the first dispersion, the mass ratio of the noble metal element to the titanium element is 1:5-20; and / or,
[0046] In the first dispersion, the mass percentage of titanium dioxide nanoparticles is 5% to 30%; and / or,
[0047] The solvent of the first dispersion liquid is water.
[0048] The beneficial effect of the mass ratio of the noble metal element to the titanium element in the first dispersion being 1:5-20 is that it can ensure that the noble metal oxide is well dispersed on the surface of the nano-titanium dioxide and that the electronic conductivity of the titanium dioxide nanoparticles is significantly improved.
[0049] As an example, in the first dispersion, the mass ratio of the noble metal element to the titanium element may be 1:5, 1:10, 1:15, or 1:20.
[0050] In some embodiments of the present application, in the second dispersion, the mass ratio of the catalyst carrier to the platinum element is 1:1.5-20.
[0051] In the second dispersion, the mass ratio of the catalyst carrier to the platinum element is 1:1.5-20, which has the beneficial effect of ensuring that the platinum is well dispersed on the catalyst carrier and that the catalyst has high catalytic activity.
[0052] In some embodiments of the present application, the first dispersion is atomized to form droplets, and the atomization rate of the first dispersion is 30 to 100 mL / min.
[0053] In some embodiments of the present application, the flow rate of the inert carrier gas is 4 to 6 L / min.
[0054] The beneficial effect of the inert carrier gas having a flow rate of 4 to 6 L / min is that the liquid droplets can be brought into the diffusion flame at a faster speed to avoid the sedimentation of the liquid droplets, while not affecting the stability of the diffusion flame.
[0055] As an example, the flow rate of the inert carrier gas can be 4 L / min, 4.5 L / min, 5 L / min, 5.5 L / min, or 6 L / min.
[0056] In some embodiments of the present application, the diffusion flame is formed by a combustion reaction between methane and oxygen, wherein the flow rate of methane is 1.5 to 2.5 L / min, and the flow rate of oxygen is 3 to 6 L / min.
[0057] The beneficial effect of a methane flow rate of 1.5 to 2.5 L / min and an oxygen flow rate of 3 to 6 L / min is that it can ensure that the diffusion flame maintains a sufficient temperature and the air flow fluctuations generated by the combustion will not be too drastic to affect the collection of the catalyst carrier.
[0058] In some embodiments of the present application, the noble metal oxide precursor is nitrate.
[0059] In some embodiments of the present application, the platinum precursor is platinum chloride.
[0060] In a second aspect, an embodiment of the present application provides a membrane electrode, wherein the anode catalyst layer of the membrane electrode comprises the catalyst described in any embodiment of the first aspect.
[0061] The membrane electrode is realized based on the catalyst described in any embodiment of the first aspect. The specific implementation of the membrane electrode can refer to the above embodiments and common knowledge in the field. Since the membrane electrode adopts part or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.
[0062] In a fourth aspect, an embodiment of the present application provides a fuel cell, comprising the membrane electrode as described in any embodiment of the second aspect.
[0063] The fuel cell is realized based on the membrane electrode described in any embodiment of the second aspect. The specific implementation of the fuel cell can refer to the above embodiments and common knowledge in the field. Since the fuel cell adopts part or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.
[0064] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.
[0065] Example
[0066] This embodiment provides a method for preparing a catalyst, and the method for preparing the catalyst comprises the following steps:
[0067] Sa: preparing a first dispersion containing titanium dioxide nanoparticles and a noble metal oxide precursor;
[0068] Sb: atomizing the first dispersion to form droplets, and introducing the droplets into a diffusion flame via an inert carrier gas;
[0069] Sc: filtering the gas flow treated by the diffusion flame through a filter membrane, collecting the solid on the filter membrane, and obtaining a catalyst carrier;
[0070] Sd: dispersing the catalyst support and the platinum precursor together in a solvent to obtain a second dispersion;
[0071] Se: The solvent of the second dispersion is removed, and the obtained solid is heated at 800° C. to obtain the catalyst.
[0072] Wherein, the precious metal is at least one of Ir, Ru, and Nb; in the first dispersion, the mass ratio of the precious metal element to the titanium element is 1:10; in the first dispersion, the mass percentage of titanium dioxide nanoparticles is 10%; in the second dispersion, the mass ratio of the catalyst carrier to the platinum element is 25%.
[0073] The first dispersion is atomized to form droplets, and the atomization rate of the first dispersion is 50 mL / min; the flow rate of the inert carrier gas is 5 L / min; the diffusion flame is formed by combustion reaction of methane and oxygen, wherein the flow rate of methane is 2 L / min, and the flow rate of oxygen is 4 L / min.
[0074] This embodiment also provides a membrane electrode, wherein the material of the cathode catalyst layer of the membrane electrode is a platinum-carbon catalyst, and the anode catalyst layer is made by spraying a catalyst slurry, wherein the catalyst slurry is composed of water and the catalyst described in this embodiment, wherein the weight percentage of the catalyst described in this embodiment in the catalyst slurry is 7%.
[0075] This embodiment further provides a fuel cell, which includes a bipolar plate, a sealing assembly and the membrane electrode described in this embodiment.
[0076] Comparative Example
[0077] This comparative example provides a membrane electrode, wherein the materials of the cathode catalyst layer and the anode catalyst layer of the membrane electrode are both platinum-carbon catalysts.
[0078] This comparative example also provides a fuel cell, which includes a bipolar plate, a sealing assembly and the membrane electrode described in this comparative example.
[0079] Related experiments and effect data:
[0080] Oxygen is introduced into the cathode of the fuel cell provided in the embodiment and nitrogen is introduced into the anode. The voltage change curve of the fuel cell is recorded to test the anti-reverse polarization performance of the fuel cell. The reverse polarization curve obtained is shown in FIG. Figure 1 shown. Figure 1 It shows that under the reverse polarity condition that the anode lacks hydrogen, the voltage of the fuel cell can be stably maintained above -1V for a long time, and the maintenance time is at least 180 minutes. This shows that the catalyst carrier of the embodiment has strong anti-reverse polarity ability and corrosion resistance.
[0081] The polarization curves of the fuel cells of the embodiment and the comparative example were tested at different current densities. The obtained polarization curves are shown in FIG. Figure 2 shown. Figure 2 This shows that the working performance of the fuel cell provided in the embodiment is better than that of the fuel cell provided in the comparative example. At the same current density, the voltage of the fuel cell provided in the embodiment is always higher than that of the comparative example. For example, at 2000 mA / cm 2 At a current density of , the voltages of the fuel cells provided in the embodiment and the comparative example are 0.665 V and 0.616 V, respectively.
[0082] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0083] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.
[0084] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for preparing a catalyst, characterized in that: The preparation method of the catalyst comprises the following steps: preparing a first dispersion containing titanium dioxide nanoparticles and a noble metal oxide precursor; atomizing the first dispersion to form droplets, and introducing the droplets into a diffusion flame via an inert carrier gas; filtering the gas flow treated by the diffusion flame through a filter membrane, collecting solids on the filter membrane, and obtaining a catalyst carrier; dispersing the catalyst support and the platinum precursor together in a solvent to obtain a second dispersion; removing the solvent of the second dispersion, and heating the obtained solid to obtain the catalyst, Wherein, the noble metal is at least one of Ir, Ru and Nb.
2. The method for preparing a catalyst according to claim 1, characterized in that: In the first dispersion, the mass ratio of the noble metal element to the titanium element is 1:5-20; and / or, In the first dispersion, the mass percentage of titanium dioxide nanoparticles is 5% to 30%; and / or, The solvent of the first dispersion liquid is water.
3. The method for preparing the catalyst according to claim 1, characterized in that: In the second dispersion, the mass ratio of the catalyst carrier to the platinum element is 1:1.5-20.
4. The method for preparing the catalyst according to claim 1, characterized in that: The first dispersion liquid is atomized to form droplets, and the atomization rate of the first dispersion liquid is 30 to 100 mL / min.
5. The method for preparing the catalyst according to claim 1, characterized in that: The liquid droplets are introduced into the diffusion flame by an inert carrier gas, and the flow rate of the inert carrier gas is 4-6 L / min.
6. The method for preparing a catalyst according to claim 1, characterized in that: The diffusion flame is formed by combustion reaction of methane and oxygen, wherein the flow rate of methane is 1.5 to 2.5 L / min, and the flow rate of oxygen is 3 to 6 L / min.
7. The method for preparing a catalyst according to claim 1, characterized in that: The noble metal oxide precursor is nitrate.
8. The method for preparing a catalyst according to claim 1, characterized in that: The platinum precursor is platinum chloride.
9. A membrane electrode, characterized in that: The anode catalyst layer of the membrane electrode is formed by the catalyst slurry according to any one of claims 1 to 8.
10. A fuel cell, characterized in that: The fuel cell comprises the membrane electrode according to claim 9.