Supported low-temperature ammonia oxidation reaction catalyst, preparation method and application

Abstract

The application relates to a supported low-temperature ammonia oxidation reaction catalyst, a preparation method and application, the catalyst is composed of an active component and a carrier, the active component is a noble metal Pt, and the carrier is W-XC72; W-XC72 is generated by mixing and hydrolyzing XC72 and tungsten chloride, a precursor of Pt is reduced under the condition of severe stirring at room temperature by using sodium borohydride as a reducing agent, and a Pt / W-XC72 catalyst is synthesized. The catalyst carrier prepared by the application has a large specific surface area, the surface metal particles are uniformly distributed, the active metal and the carrier have a strong electronic interaction, the electronic structure of the active metal is regulated, the surface interface properties between the active metal and the carrier are changed, the adsorption energy of a reaction intermediate is optimized, and then the activity of the catalyst in an ammonia oxidation reaction is effectively improved. The catalyst has a wide prospect in a low-temperature ammonia fuel cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a supported low-temperature ammonia oxidation reaction catalyst containing metal W and Pt as well as a preparation method and application thereof. BACKGROUND

[0002] Due to the large increase of environmental protection energy, H2 as a product releasing pure H2O has attracted attention; however, in practical application, there are two key problems of H2 as a clean energy, i.e. difficult storage conditions and high transportation cost. In particular, hydrogen-containing organic and inorganic compounds and carbon-containing organic matters such as methanol and ethanol have been studied as liquid fuels for direct fuel cells due to their easy storage; however, as the main liquid fuel, methanol and ethanol still have the problem of carbon emission in the process of converting the process of generating additional carbon dioxide emissions into electrochemical energy in the power generation process; in order to achieve the "double carbon" goal, reduce fuel storage and transportation cost, adapt to international energy policy, and realize zero carbon emission, the direct ammonia fuel cell with NH3 as input has attracted widespread attention of researchers; compared with the hydrogen oxidation reaction of hydrogen fuel cell, the anode ammonia electrochemical oxidation reaction (AOR) process is complex and has slow kinetics, and the reaction faces high initial potential, catalyst easy to quickly deactivate and low peak current, etc.; the development of catalysts with good stability and high activity will be beneficial to the development of direct ammonia fuel cell; at present, the commonly used AOR catalysts are noble metal catalysts represented by Pt-based catalysts and non-noble metal catalysts represented by Ni, Cu, etc.; the structural characteristics of these catalysts directly affect the catalytic performance of AOR; according to the Sabatier principle, the active metal should follow the order of the strength of the *M-N bond: Ru > Rh > Pd > Ir > Pt, Au, Ag, Cu; among them, the Pt-N bond has a relatively moderate binding energy, which makes Pt have good ammonia oxidation activity; therefore, Pt-based catalysts are the most common noble metal catalysts for AOR; however, low reserves and high price limit its large-scale application; how to improve the atomic utilization rate and unit activity of Pt is the key to the research of Pt-based catalysts.

[0003] Chen et al. designed a W / WO2 metal-type heterojunction material on a foam nickel substrate, which can effectively improve the hydrogen production activity of alkaline water electrolysis through synergistic catalytic effect; (Nat Commun.2023, 14, 5363.) Li et al. synthesized tungsten-doped catalyst material W0.03Fe0.2Ni(OH)2LDH, which showed excellent electrochemical oxygen evolution (OER) and hydrogen evolution (HER) performance; (Chinese Journal of Inorganic Chemistry.2020, 36(8): 1492-1498); but these studies have not applied transition metal type catalysts to ammonia electrocatalytic oxidation; the performance breakthrough of ammonia oxidation anode catalyst has not been achieved.

[0004] Chinese patent CN118904384A discloses a low-temperature ammonia oxidation catalyst and a preparation method thereof; the invention

[0005] By adding part of the molecular sieve material of the upper SCR coating layer to the lower noble metal coating layer, and then coating the mixed coating layer on the silicate mineral carrier, a catalyst is obtained after drying and calcination; the diffusion resistance can be reduced, the low-temperature NH3 oxidation activity can be increased, the generation of by-products NOx and N2O can be reduced, and the authenticity activity of the noble metal coating layer is embodied; in the ammonia electrocatalytic oxidation process, especially in the application of ammonia fuel cells, the Pt atom utilization rate and unit activity are not high, and the catalytic effect is not good; and the preparation process involves the preparation and coating of two layers of coating, the process is complex, the manufacturing cost is high, and the error rate is high. SUMMARY

[0006] In view of the low platinum reserves, high price, low platinum metal atom utilization rate and unit activity, low catalytic efficiency in the ammonia electrocatalytic oxidation process, and complex preparation process of the platinum-based catalyst in the prior art, a supported low-temperature ammonia oxidation reaction catalyst suitable for direct ammonia fuel cells, a preparation method and applications thereof are provided, which are low in price, simple in preparation method, and have good catalytic activity and catalytic stability.

[0007] The technical solution adopted by the present application to solve its technical problems is: a preparation method of a supported low-temperature ammonia oxidation reaction catalyst, comprising the following steps: step one: adding a carbon carrier into 100-150 milliliters of ethanol or 40 mL of isopropanol and performing ultrasonic dispersion; obtaining a mixed solution; step two: adding tungsten chloride into the mixed solution prepared in step one and continuing ultrasonic dispersion; after dispersion, continuously stirring for more than 20 minutes; step three: adding 1-2 milliliters of deionized water dropwise during the stirring process of step two; after continuing stirring for 20 minutes, transferring to an oil bath pot, condensing and refluxing at 80 DEG C for 4 hours, and then drying; obtaining a precursor powder; step four: heating the dried precursor powder under a methane atmosphere at a heating rate of 2-3 DEG C per minute, and then calcining to obtain a tungsten metal carrier; step five: first mixing the tungsten metal carrier with isopropanol and deionized water and performing ultrasonic dispersion, then adding a chloroplatinic acid solution and continuing ultrasonic dispersion, and then stirring the solution and adding a mixed solution containing sodium borohydride and sodium hydroxide dropwise, filtering and washing after stirring for 4-5 hours, and finally vacuum drying to obtain a supported low-temperature ammonia oxidation reaction catalyst.

[0008] Further, in step one, the carbon carrier is mixed with 100-150 milliliters of ethanol or 40 mL of isopropanol and deionized water, and then ultrasonic dispersion is performed to obtain a mixed solution.

[0009] Further, in step five, 0.1M, 50mL of sodium hydroxide solution is configured, sodium borohydride is mixed with sodium hydroxide to obtain a mixed solution containing sodium borohydride and sodium hydroxide.

[0010] Further, in step two, the tungsten chloride is tungsten tetrachloride, and the content of tungsten element in the tungsten chloride is 10-20%.

[0011] Further, in step four, the dried precursor powder is heated to 700-800 DEG C under a methane atmosphere, and then calcined at 700-800 DEG C for 1-3 hours to obtain a tungsten metal carrier.

[0012] Further, in step five, the loading amount of platinum metal in the aluminum platinum acid solution is 20%.

[0013] Further, in step five, vacuum drying is carried out at 60-80 DEG C for 12 to 24h.

[0014] A supported low-temperature ammonia oxidation reaction catalyst, comprising an active component and a composite carrier, the composite carrier being a mixture containing tungsten metal and a carbon carrier, and the active component being metal platinum; the mass fraction of the metal platinum being 10-30%.

[0015] A supported low-temperature ammonia oxidation reaction catalyst, the supported low-temperature ammonia oxidation reaction catalyst being applied to an ammonia fuel cell.

[0016] The supported low-temperature ammonia oxidation reaction catalyst, the preparation method and the application have the advantages that the catalyst carrier has a large specific surface area, the surface metal particles are uniformly distributed, and the active metal and the carrier have strong electronic interaction; the electronic structure of the active metal is regulated, the surface interface properties between the active metal and the carrier are changed, the adsorption energy of the reaction intermediates is optimized, and thus the activity of the catalyst in the ammonia oxidation reaction is effectively improved; the W-XC72 carrier is used, then the metal is loaded by a simple impregnation liquid phase reduction method, the operation is convenient, and no pollution to the environment and no harmful substances are generated; the prepared Pt / W-XC72 carrier catalyst has a lower ammonia oxidation starting potential and a better catalytic performance than the Pt / XC72 catalyst in the electrocatalytic ammonia oxidation; and the catalyst has a broad prospect in the ammonia fuel cell, especially in the low-temperature ammonia fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present application, the drawings required in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1XRD patterns of XC72 and W-XC72 composite support are compared;

[0019] Figure 2 CV curve of Pt / XC72 catalyst prepared in Example 1 in 1M KOH + 0.1M NH3 solution;

[0020] Figure 3 CV curve of Pt / W-XC72(10%) catalyst prepared in Example 2 in 1M KOH + 0.1M NH3 solution;

[0021] Figure 4 CV curve of Pt / W-XC72(20%) catalyst prepared in Example 3 in 1M KOH + 0.1M NH3 solution;

[0022] Figure 5 SEM and EDX element distribution pictures of Pt / XC72 catalyst prepared in Example 1.

[0023] Figure 6 SEM and EDX element distribution pictures of Pt / W-XC72(10%) catalyst prepared in Example 2. DETAILED DESCRIPTION

[0024] To make the possible application scenarios, technical principles, specific schemes that can be implemented, purposes and effects that can be achieved of the present application clear, the following will be described in detail in combination with the specific embodiments listed and the accompanying drawings. The embodiments described in the present document are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0025] In the present document, the term "embodiment" means that the specific features, structures or characteristics described in combination with the embodiments can be included in at least one embodiment of the present application. The term "embodiment" appearing at various positions in the specification does not necessarily refer to the same embodiment, and does not particularly limit the independence or association between other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0026] Unless otherwise defined, the meanings of the technical terms used in the present document are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms in the present document is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0027] Hereinafter, specific embodiments of the present application are described in detail with appropriate reference to the accompanying drawings. However, there are cases where unnecessary detailed description is omitted. For example, there are cases where detailed description of matters known to those skilled in the art, repeated description of substantially identical configurations, are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to allow those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0028] The "ranges" disclosed herein are defined with their lower and upper limits, and a given range is defined with a lower limit and an upper limit. The lower and upper limits define the boundaries of a particular range. Ranges defined by these limits can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise stated, a numerical range "a-b" indicates a shorthand way of describing each and every intervening real number with the range from "a" to "b", wherein "a" and "b" are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed herein, and "0-5" is merely a shorthand way of describing these numerical combinations. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0029] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0030] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0031] If not specifically stated, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order. For example, the method can comprise steps (a), (b), and (c), or steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0032] The terms "comprise" and "comprising", as used herein, mean "including" or "including without limitation", unless specifically indicated otherwise. For example, the terms "comprise" and "comprising" can mean that other components can also be included or included without limitation.

[0033] The terms "one or more", "at least one", and "one or more of the group consisting of" as used herein, include the number zero. For example, "one or more of A and B" means "A, B, or A and B".

[0034] The term "or" as used herein, unless otherwise indicated, is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0035] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] As shown in Figure 1 The preparation method of the supported low-temperature ammonia oxidation reaction catalyst comprises the following steps:

[0037] Step 1: Add carbon carrier to 100-150 mL of ethanol or 40 mL of isopropanol and ultrasonic dispersion; obtain a mixed solution;

[0038] Step 2: Add tungsten chloride to the mixed solution prepared in step 1 and continue to ultrasonic dispersion; after dispersion, continue stirring for more than 20 min;

[0039] Step 3: During the stirring process of step 2, add 1-2 mL of deionized water dropwise; continue stirring for 20 min, then transfer to an oil bath, condense and reflux at 80℃ for 4 h, and then dry; obtain a precursor powder;

[0040] Step 4: Dry the precursor powder under a methane atmosphere at a temperature increasing rate of 2-3℃ per minute, then calcine to obtain a tungsten metal carrier;

[0041] Step five: first, the tungsten metal carrier is mixed with isopropyl alcohol and deionized water and ultrasonic dispersion is performed, then chloroplatinic acid solution is added and ultrasonic dispersion is continued, then the solution is stirred and a mixed solution containing sodium borohydride and sodium hydroxide is added dropwise, after stirring for 4-5 h, filtration and washing are performed, and finally vacuum drying is performed to obtain a supported low-temperature ammonia oxidation reaction catalyst.

[0042] In step one, the carbon carrier is Vulcan XC72; the Vulcan XC72 carrier is placed in a beaker, a certain volume of deionized water is added, and then 100-150 mL of ethanol or 40 mL of isopropyl alcohol is added; ultrasonic dispersion is performed to obtain a mixed solution; in step two, tungsten chloride, such as tungsten tetrachloride, is added to the mixed solution prepared in step one and ultrasonic dispersion is continued, and after dispersion, vigorous stirring is performed for more than 20 minutes; in step three, 1-2 mL of deionized water is slowly added dropwise during vigorous stirring; after dropwise addition, stirring is continued for 20 minutes, the stirred solution is transferred to a round-bottom flask, and then transferred to an oil bath; after condensation refluxing at 80°C for 4 hours, filtration, washing and drying are performed to obtain a precursor powder; in step five, the tungsten metal carrier is first placed in a beaker, then isopropyl alcohol and deionized water are added for mixing, mixing is performed after mixing, then chloroplatinic acid solution is added to the above mixed solution and ultrasonic dispersion is continued; at the same time, a certain molar concentration of sodium hydroxide solution is prepared, sodium borohydride is mixed with the prepared sodium hydroxide to obtain a mixed solution, and a mixed solution containing 20-40 mg of sodium borohydride and the prepared sodium hydroxide is obtained; the sodium borohydride can reduce the platinum metal in the added platinum chloride solution, which is conducive to the loading of the platinum metal on the carrier in the subsequent process; under vigorous stirring, the mixed solution containing sodium borohydride and sodium hydroxide is slowly added dropwise into the catalyst precursor solution, sealed with plastic wrap, and continues to stir for 4-5 h to complete the reaction, filtration (until the filtrate is free of chloride ions), washing and vacuum drying are performed to obtain a supported low-temperature ammonia oxidation reaction catalyst.

[0043] Example 1

[0044] Step one: 80 mg of Vulcan XC72 carrier is placed in a 300 mL beaker, 40 mL of deionized water and 40 mL of isopropyl alcohol are added; ultrasonic dispersion is performed for 30 minutes; a mixed solution is obtained;

[0045] Step two: 1.06 mL of chloroplatinic acid solution with a platinum metal loading of 20% is added to the mixed solution prepared in step one and ultrasonic dispersion is continued; after dispersion, stirring is continued for 20 min; at the same time, 50 mL of 0.1 mol NaOH solution is prepared, and then 40 mg of NaBH4 is dissolved in the NaOH solution;

[0046] Step three: stir the solution and drop the mixture containing sodium borohydride and sodium hydroxide, filter and wash after stirring for 4.5h, and finally vacuum dry at 70°C for 12 hours to obtain the supported low-temperature ammonia oxidation reaction catalyst Pt / XC72.

[0047] Example 2

[0048] Preparation of precursor:

[0049] Step one: 450mg Vulcan XC72 carrier in a 250mL beaker, add 120mL ethanol; ultrasonic dispersion for 30 minutes; obtain a mixed solution;

[0050] Step two: add 88.57mg of tungsten tetrachloride (with tungsten element content of 10%) to the mixed solution prepared in step one and continue to ultrasonic dispersion; continue to stir for 20min after dispersion;

[0051] Step three: drop 1.5ml of deionized water during the stirring process of step two; continue to stir for 20min and then transfer to an oil bath, condense and reflux at 80°C for 4 hours, and then perform suction filtration and drying; obtain the precursor powder;

[0052] Step four: heat the dried precursor powder to 750°C at a heating rate of 3°C per minute under a methane atmosphere, and then calcine at 750°C for 2 hours to obtain the W-XC72(10%) carrier;

[0053] Preparation of catalyst:

[0054] Step one: 80mg W-XC72(10%) carrier in a 300mL beaker, add 40mL deionized water and 40mL isopropyl alcohol; ultrasonic dispersion for 30 minutes; obtain a mixed solution;

[0055] Step two: add 1.06mL of platinum metal loading 20% chloroplatinic acid solution to the mixed solution prepared in step one and continue to ultrasonic dispersion; continue to stir for 20min after dispersion; at the same time, configure 50mL of 0.1mol NaOH solution, and then dissolve 50mg NaBH4 in the NaOH solution;

[0056] Step three: stir the solution and drop the mixture containing sodium borohydride and sodium hydroxide, seal with plastic wrap after complete dropwise addition, filter and wash after stirring for 5h, and finally vacuum dry at 60°C for 12 hours to obtain the supported low-temperature ammonia oxidation reaction catalyst Pt / W-XC72(10%).

[0057] Example 3

[0058] Preparation of precursor:

[0059] Step one: 400 mg Vulcan XC72 support was added to a 250 mL beaker, 150 mL ethanol was added; ultrasonic dispersion for 30 minutes; a mixed solution was obtained;

[0060] Step two: 177.14 mg of tungsten tetrachloride (20% tungsten element content) was added to the mixed solution prepared in step one and ultrasonic dispersion was continued; after dispersion, stirring was continued for 20 min;

[0061] Step three: 2 mL of deionized water was added dropwise during the stirring of step two; after 20 minutes of continuous stirring, it was transferred to an oil bath pot, and after condensation reflux at 80°C for 4.5 hours, it was filtered and dried; a precursor powder was obtained;

[0062] Step four: the dried precursor powder was heated to 750°C at a heating rate of 2°C per minute under a methane atmosphere, and then calcined at 750°C for 2 hours to obtain a W-XC72 (20%) support;

[0063] Preparation of catalyst:

[0064] Step one: 80 mg W-XC72 (20%) support was added to a 300 mL beaker, 45 mL deionized water and 45 mL isopropyl alcohol were added; ultrasonic dispersion for 30 minutes; a mixed solution was obtained;

[0065] Step two: 1.35 mL of a 20% platinum metal loading chloroplatinic acid solution was added to the mixed solution prepared in step one and ultrasonic dispersion was continued; after dispersion, stirring was continued for 20 min; at the same time, 50 mL of 0.1 mol NaOH solution was prepared, and then 45 mg of NaBH4 was dissolved in the NaOH solution;

[0066] Step three: the solution was stirred and the mixed solution containing sodium borohydride and sodium hydroxide was added dropwise, sealed with plastic wrap after complete dropwise addition, stirred for 4 h, then filtered and washed, and finally vacuum dried at 80°C for 7 hours to obtain a supported low-temperature ammonia oxidation catalyst Pt / W-XC72 (20%).

[0067] The application also discloses a metal catalyst of a supported low-temperature ammonia oxidation catalyst prepared by the above embodiment, a metal-support surface interface active site construction, including an active component and a composite support, the composite support being a mixture containing tungsten metal and a carbon support, for example, W-XC72; the active component being metal platinum; the mass fraction of the metal Pt being 10-30 wt.%.

[0068] The application also discloses an application of the metal catalyst of the supported low-temperature ammonia oxidation catalyst prepared by the above embodiment, for example, an application in ammonia electrocatalytic oxidation, more specifically, the metal catalyst of the supported low-temperature ammonia oxidation catalyst is suitable for a low-temperature ammonia fuel cell.

[0069] The catalyst prepared in the following examples was electrochemically tested in an alkaline solution as follows:

[0070] 2-4 mg of the catalyst prepared in this example was weighed into a 5 mL sample bottle with a 1:1 ratio of isopropanol and Nafion solution, and the solution was uniformly dispersed by ultrasonic to obtain a slurry. A certain amount of the solution was slowly added to a glassy carbon electrode, and the metal content loaded on the glassy carbon electrode was controlled to be 4 μg. After normal drying at room temperature, electrochemical testing was performed. The electrochemical testing used a five-port electrolytic cell, about 50-70 mL of electrolyte was poured into the five-port electrolytic cell (along the edge of the five-port electrolytic cell), a glassy carbon working electrode was placed in the center of the electrolytic cell (above the solution surface), a graphite rod was placed as a counter electrode, a reference electrode Luggin capillary (Hg / HgO) was placed, and a gas inlet pipe and a gas outlet device were placed. Before testing, Ar gas was passed through the upper end of the gas inlet pipe to remove dissolved oxygen. During testing, the gas inlet pipe was switched to the lower end for continuous aeration (to avoid gas interference and to be in an Ar atmosphere), and the working electrode was placed at an appropriate depth below the liquid surface.

[0071] The catalyst was activated by scanning 15-20 times at a speed of 100 mV / s in an Ar-saturated 1 M KOH solution. A certain range of voltage, scan rate, and scan number were set to clean and activate the electrode surface. If the curves overlap, the activation is successful. Then, the test was switched to an Ar-saturated 1 M KOH + 0.1 M NH3 alkaline solution, and the catalyst was recovered at a reduction potential (-0.85 V vs. Hg / HgO) for at least 100 s. Then, a CV curve was tested at 5 mV / s and 3-4 cycles as a basis for catalyst performance testing.

[0072] The physical structure characterization test method of the catalyst prepared in the following examples in an alkaline solution is as follows:

[0073] The powder X-ray diffractometer (XRD) used a X'Pert3 Powder instrument from the Netherlands PANalytical company, a Cu target Kα radiation source with a laser incident wavelength of 0.15406 nm, a working voltage of 45 kV, and a current of 40 mA. The results were analyzed by HighScore Plus to obtain the composition and crystal structure information of the sample. The test range was: 2θ = 10-90°.

[0074] Field emission scanning electron microscopy (SEM) used a S-4800 type field emission scanning electron microscope from Hitachi company to observe the morphology and size of the catalyst surface. The sample to be tested was dried before testing, and the carrier and catalyst samples with poor conductivity were sprayed before testing. The test working voltage was 5 kV, and the current was 7 μA.

[0075] The XRD patterns of the supports prepared in Examples 1, 2 and 3 are shown in Figure 1 The XRD patterns of the supports prepared in Examples 2 and 3 are consistent in structure; the XC72 is mainly composed of a peak group around 25.8°. There are four characteristic diffraction peaks at positions of 40.42°, 58.36°, 73.33° and 86.91°, which are attributed to the metal W species, indicating the successful preparation of the metal W.

[0076] The catalyst activity is shown in Figures 2-4 The activities of Pt / XC72, Pt / W-XC72(10%) and Pt / W-XC72(20%) are 36, 133 and 58 A g-1Pt, respectively. It can be found that the peak current density of Pt / W-XC72(10%) is the best and the performance is the highest, indicating that the metal W as the support can effectively improve the performance.

[0077] As shown in Figure 3 and Figure 4 The electrochemical activities of Pt / W-XC72(10%) and Pt / W-XC72(20%) are compared, and it can be found that the content of W also has an impact on the performance.

[0078] The morphology and structure information of the catalysts are shown in Figure 5 and Figure 6 It can be seen that the Pt is successfully reduced and loaded on the support and uniformly distributed on the support.

[0079] Obviously, the above examples are only examples for clearly illustrating, but not limitation to the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for the preparation of a supported low-temperature ammonia oxidation reaction catalyst, characterized by: The method comprises the following steps: Step 1: carbon carrier is added into 100-150 ml of ethanol or 40 ml of isopropanol and ultrasonic dispersion is performed; A mixed solution is obtained; Step 2: tungsten chloride is added into the mixed solution prepared in step 1 and ultrasonic dispersion is continued; after dispersion, stirring is continued for more than 20 min; Step 3: 1-2 ml of deionized water is added dropwise during the stirring of step 2; after stirring for 20 min, it is transferred to an oil bath pot, and after condensation reflux at 80℃ for 4 h, drying is performed; a precursor powder is obtained; Step 4: the dried precursor powder is heated at a heating rate of 2-3℃ per min under a methane atmosphere, and then calcination is performed to obtain a tungsten metal carrier; Step 5: the tungsten metal carrier is mixed with isopropanol and deionized water and ultrasonic dispersion is performed, chloroplatinic acid solution is added and ultrasonic dispersion is continued, then the solution is stirred and a mixed solution containing sodium borohydride and sodium hydroxide is added dropwise, stirring is performed for 4-5 h, then filtration and washing are performed, and finally vacuum drying is performed to obtain a supported low-temperature ammonia oxidation reaction catalyst.

2. The method for preparing a supported low-temperature ammonia oxidation reaction catalyst according to claim 1, characterized by: In step 1, the carbon carrier is mixed with 100-150 ml of ethanol or 40 ml of isopropanol and deionized water, and ultrasonic dispersion is performed to obtain a mixed solution.

3. The method of claim 1, wherein the method comprises: In step 5, a 0.1M, 50ml sodium hydroxide solution is prepared, sodium borohydride is mixed with sodium hydroxide to obtain a mixed solution containing sodium borohydride and sodium hydroxide; the mass of the mixed solution containing sodium borohydride and sodium hydroxide ranges from 20 to 40 mg.

4. The method of claim 1, wherein the method comprises: In step 2, the tungsten chloride is tungsten tetrachloride, and the content of tungsten element in the tungsten chloride is 10-20%.

5. The method of claim 1, wherein the method is characterized by: In step 4, the dried precursor powder is heated to 700-800℃ under a methane atmosphere, and then calcination is performed at 700-800℃ for 1-3 h to obtain a tungsten metal carrier.

6. The method of claim 1, wherein the method comprises: In step 5, the loading amount of platinum metal in the chloroplatinic acid solution is 20%.

7. The method of claim 1, wherein the method comprises: In step 5, vacuum drying is performed at 60-80℃ for 12 to 24 h.

8. The supported low-temperature ammonia oxidation reaction catalyst produced by the production method of the supported low-temperature ammonia oxidation reaction catalyst according to any one of claims 1 to 7, characterized by The supported low-temperature ammonia oxidation reaction catalyst comprises an active component and a composite carrier, the composite carrier is a mixture containing a tungsten metal and a carbon carrier, and the active component is a metal platinum; the mass fraction of the metal platinum is 10-30%.

9. The supported low-temperature ammonia oxidation reaction catalyst produced by the production method of the supported low-temperature ammonia oxidation reaction catalyst according to any one of claims 1 to 7, characterized by The supported low-temperature ammonia oxidation reaction catalyst is applied to an ammonia fuel cell.

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