Carbon-supported platinum-based alloy catalysts, methods of making and using the same

Abstract

The present disclosure provides a carbon-supported platinum-based alloy catalyst and a preparation method and application thereof, wherein the preparation method of the carbon-supported platinum-based alloy catalyst comprises: providing an impregnation solution containing a platinum source and a non-noble metal source; dispersing and impregnating a carbon-based carrier in the impregnation solution, removing water to obtain a precursor mixture; and performing calcination and annealing treatment on the precursor mixture under a mixed gas atmosphere comprising hydrogen, carbon monoxide and an inert gas to obtain the carbon-supported platinum-based alloy catalyst.

Description

Technical Field

[0001] This disclosure relates to the field of nanomaterials technology, and in particular to a carbon-supported platinum-based alloy catalyst, its preparation method, and its application. Background Technology

[0002] Platinum, a precious metal, has become one of the main industrial catalyst materials due to its excellent catalytic activity in key industrial catalytic reactions such as propane dehydrogenation, oxygen reduction, hydrogen evolution, and water-gas shift reaction. However, traditional bulk platinum catalysts are difficult to apply efficiently and economically due to their low active surface area and atom utilization. Therefore, supported nanocatalysts are considered ideal alternatives due to their high active surface area and atom utilization.

[0003] Currently, the impregnation-reduction method is mainly used in industry to prepare supported platinum-based nanocatalysts. However, this method tends to result in large and unevenly distributed platinum particles, which in turn affects catalytic performance. Although a solvothermal reduction method has been developed to synthesize uniform platinum-based nanocrystals, its large-scale application is limited by high solvent costs and difficulties in product separation. While methods such as support functionalization and doping have effectively improved the thermal stability of platinum-based nanoparticles, they still face challenges such as complex synthesis steps and high production costs. Furthermore, due to the limited stabilizing effect of modification and doping methods, the resulting alloy catalysts often have low active metal content (less than 50 wt%), making it difficult to meet the requirements for high-efficiency catalysis.

[0004] Therefore, developing a new method that can efficiently synthesize small-sized, highly active platinum-based nanocatalysts while also being economically feasible and industrially applicable has become an urgent technical challenge and is of great significance for promoting the development of the industrial catalysis field. Summary of the Invention

[0005] In view of this, the main objective of this disclosure is to provide a carbon-supported platinum-based alloy catalyst, its preparation method, and its application, in order to at least partially solve at least one of the aforementioned technical problems.

[0006] To achieve the above objectives, the technical solution disclosed herein is as follows:

[0007] In one aspect of this disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided, comprising:

[0008] Provide impregnation solutions containing platinum sources and non-precious metal sources;

[0009] The carbon-based support is dispersed and impregnated in an impregnation solution, and the water is removed to obtain a precursor mixture;

[0010] The precursor mixture was calcined and annealed in a mixed atmosphere including hydrogen, carbon monoxide and inert gas to obtain a carbon-supported platinum-based alloy catalyst.

[0011] In another aspect of this disclosure, a carbon-supported platinum-based alloy catalyst prepared by the above-described preparation method is provided. The carbon-supported platinum-based alloy catalyst includes a carbon-based support and platinum-based alloy nanoparticles supported on the surface of the carbon-based support; wherein the platinum-based alloy nanoparticles are an alloy of platinum and non-precious metals.

[0012] In another aspect of this disclosure, the application of the above-described carbon-supported platinum-based alloy catalyst in oxygen reduction reactions is provided.

[0013] According to embodiments of this disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided. Water is used as a solvent to mix a platinum source with a non-precious metal source to obtain an impregnation solution. A carbon-based support is directly impregnated in the impregnation solution to remove water, obtaining a precursor mixture. This method reduces costs and solvent pollution. The precursor mixture is then calcined and annealed under a mixed atmosphere of hydrogen, carbon monoxide, and an inert gas to prepare a high-performance carbon-supported platinum-based alloy catalyst. During the preparation process, hydrogen in the mixed atmosphere can rapidly reduce platinum in the precursor mixture, while carbon monoxide can effectively inhibit the rapid growth of platinum clusters or platinum nanoparticles, causing their size to increase slowly, thereby ensuring the size uniformity and stability of the platinum nanoparticles. This results in a carbon-supported platinum-based alloy catalyst with smaller size and higher loading. Attached Figure Description

[0014] Figure 1 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure, obtained by atomic-resolution scanning transmission electron microscopy.

[0015] Figure 2 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure using a scanning transmission electron microscope;

[0016] Figure 3 This is a particle size distribution diagram of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure;

[0017] Figure 4 The X-ray diffraction pattern of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure is shown below.

[0018] Figure 5 The graphs show the polarization curves of commercially available platinum-carbon catalysts and the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure under the same loading conditions for catalytic oxygen reduction reaction.

[0019] Figure 6 The X-ray diffraction pattern of the carbon-supported platinum-nickel alloy catalyst in Example 2 of this disclosure is shown below.

[0020] Figure 7This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 of this disclosure, obtained by atomic-resolution scanning transmission electron microscopy.

[0021] Figure 8 This is a bright-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 2 of this disclosure using a transmission electron microscope.

[0022] Figure 9 This is a bright-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3 of this disclosure using a transmission electron microscope.

[0023] Figure 10 X-ray diffraction pattern of carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of this disclosure;

[0024] Figure 11 The X-ray diffraction pattern of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of this disclosure is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments.

[0026] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this disclosure.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] Platinum-based catalysts are catalysts with platinum as the main active component, and are divided into pure platinum catalysts and platinum alloy catalysts. Platinum alloy catalysts are further classified into disordered platinum alloy catalysts and platinum intermetallic compound catalysts based on the regularity of atomic arrangement. Due to its excellent catalytic activity, platinum exhibits outstanding performance in many key industrial reactions, making platinum-based catalysts highly valuable commercially. However, platinum and other precious metals are scarce in the Earth's crust. Therefore, compared to pure platinum, platinum alloys possess richer and more tunable local coordination environments and electronic structures. Supported nano-platinum-based alloy catalysts, due to their high active specific surface area and atomic utilization rate, are considered ideal alternatives to traditional bulk catalysts.

[0029] In the process of realizing the concept disclosed herein, it was found that although commonly used industrial methods such as impregnation-reduction and solvothermal reduction can be used to prepare supported platinum-based nanocatalysts, there are still many problems, such as large and unevenly distributed platinum particles, high solvent cost and difficult separation, complicated synthesis process, and low active metal content of alloy catalysts, which limit their large-scale application.

[0030] Therefore, this disclosure proposes a method for preparing carbon-supported platinum-based alloy catalysts based on aqueous solution impregnation. Water is used as the solvent to mix a platinum source and a non-precious metal source to obtain an impregnation solution. The carbon-based support is dispersed and impregnated in the impregnation solution, thereby reducing costs and solvent pollution. By controlling the reducing atmosphere, hydrogen can rapidly reduce the platinum source, initially forming platinum clusters or platinum nanoparticles. Due to the high adsorption capacity of platinum metal for carbon monoxide, carbon monoxide is adsorbed on the surface of the initially formed platinum clusters or platinum nanoparticles, effectively inhibiting their growth. This allows the reduced platinum nanoparticles to alloy with the non-precious metal, forming small-sized platinum alloy nanoparticles. Furthermore, by optimizing the calcination and annealing processes, the nanoparticle size can be further controlled, while simultaneously transforming into ordered alloy nanoparticles (i.e., intermetallic compounds), thereby enhancing the catalytic activity of the catalyst. The preparation method disclosed herein does not require the use of organic solvents, organometallic salts, sacrificial agents, templates, or other additives, simplifying the preparation process and providing mild reaction conditions, thus reducing production costs. It enables the mass production of carbon-supported platinum-based alloy catalysts while ensuring small catalyst size, high loading, and high activity. It has significant economic feasibility and industrial applicability, providing a novel technical route for the preparation of platinum-based catalysts.

[0031] According to one aspect of this disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided, comprising:

[0032] An impregnation solution containing a platinum source and a non-precious metal source is provided; a carbon-based support is dispersed and impregnated in the impregnation solution, and water is removed to obtain a precursor mixture; the precursor mixture is calcined and annealed under a mixed atmosphere including hydrogen, carbon monoxide and inert gas to obtain a carbon-supported platinum-based alloy catalyst.

[0033] According to embodiments of this disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst based on aqueous solution impregnation is provided. By using water as a solvent, a platinum source mixed with a non-precious metal source is directly impregnated onto a carbon support, thereby reducing costs and solvent pollution. During the preparation process, a mixture of hydrogen, carbon monoxide, and an inert gas is used as the atmosphere for calcination and annealing. Hydrogen first rapidly reduces the platinum precursor, forming primary platinum clusters or extremely small platinum nanoparticles. Subsequently, carbon monoxide adsorbs onto the surface of the platinum clusters and nanoparticles, effectively inhibiting their rapid growth and allowing their size to increase slowly. As the temperature further increases, the non-precious metal salt is reduced, and the reduced non-precious metal alloys with the smaller platinum nanoparticles, ultimately forming small-sized platinum alloy nanoparticles on the carbon support, thus preparing a small-sized, high-load carbon-supported platinum-based alloy catalyst.

[0034] According to embodiments of this disclosure, the hydrogen content in the mixed atmosphere is 3% to 10%, for example, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., preferably 5% to 8%. Hydrogen is mainly used to reduce the precursor, forming platinum alloy nanoparticles. When the hydrogen content is too low (e.g., less than 3%), the reduction rate is slow, which may lead to incomplete reduction of the platinum precursor and affect the catalyst activity; when the hydrogen content is too high (greater than 10%), the reduction rate is too fast, which may lead to rapid growth of platinum nanoparticles, resulting in excessively large sizes and reducing the specific surface area and activity of the catalyst.

[0035] The carbon monoxide content is 1% to 15%, for example, it can be 1%, 5%, 7%, 10%, 13%, 15%, 19%, etc., preferably 5% to 10%. Carbon monoxide is adsorbed on the surface of platinum alloy nanoparticles, inhibiting their rapid growth and causing the particle size to increase slowly. When the carbon monoxide content is too low (e.g., less than 1%), the inhibitory effect is insufficient, and the platinum alloy nanoparticles may grow rapidly, resulting in excessively large sizes; when the carbon monoxide content is too high (e.g., greater than 15%), it may excessively inhibit the growth of platinum nanoparticles, resulting in excessively small particle sizes, affecting the stability and selectivity of the catalyst.

[0036] The inert gas content is 75% to 96%, for example, it can be 75%, 80%, 83%, 85%, 87%, 90%, 96%, etc. The inert gas includes any one of argon, helium, and nitrogen. The inert gas acts as a balancing gas to regulate the total pressure of the mixed atmosphere and the partial pressure of each component, while providing a stable calcination and annealing environment.

[0037] According to embodiments of this disclosure, the ratio of hydrogen, carbon monoxide, and inert gas in the mixed atmosphere can effectively control the size of platinum-based alloy nanoparticles. Hydrogen reduces the precursor, carbon monoxide inhibits particle growth, and the inert gas provides a stable environment; the synergistic effect of these three ensures the size, activity, and stability of the platinum alloy nanoparticles, thereby improving the overall performance of the carbon-supported platinum-based alloy catalyst.

[0038] According to embodiments of this disclosure, the flow rate of the mixed atmosphere is 10~150 sccm, for example, it can be 10 sccm, 30 sccm, 50 sccm, 80 sccm, 100 sccm, 130 sccm, 150 sccm, etc. Flow rates within this range ensure sufficient contact between the components while avoiding excessively fast or slow reaction rates, thereby achieving uniformity and controllability of the reaction.

[0039] According to embodiments of this disclosure, the platinum source includes any one of chloroplatinic acid, platinum acetylacetonate, platinum tetraamminenitrate, potassium chloroplatinate, sodium chloroplatinate, and ammonium chloroplatinate. The non-precious metal source is a soluble non-precious metal salt, selected from nitrates or chlorides of any one of vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc. Specifically, it can be any one of vanadium trichloride, chromium chloride hexahydrate, manganese nitrate tetrahydrate, manganese chloride, ferric nitrate nonahydrate, ferric chloride, cobalt nitrate hexahydrate, cobalt chloride hexahydrate, nickel nitrate hexahydrate, nickel chloride hexahydrate, copper nitrate trihydrate, copper chloride dihydrate, zinc nitrate hexahydrate, and zinc chloride. The carbon-based support can be commercial carbon black, specifically any one of Ketjen Black EC300-J, Ketjen Black EC600-JD, BP2000, and XC-72R. This disclosure allows for the preparation of different types of carbon-supported platinum-based alloy catalysts by changing the types of platinum and non-precious metal sources, meeting diverse industrial needs.

[0040] According to embodiments of this disclosure, the molar ratio of the non-precious metal source to the platinum source is (0.3~1.5):1, for example, it can be 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, etc. By controlling the molar ratio of the non-precious metal salt to the platinum precursor, the degree of alloying can be effectively controlled. When the molar ratio of the non-precious metal source to the platinum source exceeds the range of 1.5:1, the loading of non-precious metals in the formed alloy may be too high, which reduces the stability of the catalyst in the oxygen reduction process and is not conducive to the formation of an ordered alloy; if the molar ratio of the non-precious metal source to the platinum source is too low (below 0.3:1), a platinum-based alloy cannot be effectively formed, and it is also not conducive to the formation of an ordered alloy.

[0041] The mass ratio of carbon-based support, platinum source, and non-precious metal source is 2:(6~10):(1.2~4.5), for example, 2:6:1.2, 2:8:2, 2:10:3, 2:10:3.5, 2:10:4.5, etc. By adjusting the amount of carbon-based support added, the loading of platinum-based alloy particles on the catalyst can be controlled to ensure the uniformity and catalytic activity of the carbon-supported platinum-based alloy catalyst.

[0042] According to embodiments of this disclosure, dispersing and impregnating a carbon-based support in an impregnation solution includes: mixing a platinum source and a non-precious metal source in an aqueous solution to obtain an impregnation solution with a concentration of 4-18 mmol / L; impregnating the carbon-based support in the impregnation solution for 2-20 hours, and removing water to obtain a precursor mixture. The concentration of the impregnation solution can be selected, for example, 4 mmol / L, 6 mmol / L, 8 mmol / L, 9 mmol / L, 12 mmol / L, etc., and the impregnation time can be selected, for example, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 15 hours, 20 hours, etc., preferably 5-15 hours, more preferably 8-10 hours.

[0043] According to embodiments of this disclosure, by controlling the concentration of the impregnation solution and the impregnation time through wet impregnation, the dispersion degree of the precursor mixture on the carbon-based support can be effectively adjusted, thereby facilitating the control of the particle size of small-sized, high-load carbon-supported platinum-based alloy catalysts. For example, at an impregnation solution concentration of 6–12 mmol / L and an impregnation time of 8–12 h, platinum-based alloy nanoparticles with a particle size of 3 nm–5 nm can be obtained, thus yielding carbon-supported platinum-based alloy catalysts with small particle sizes. Furthermore, compared to catalyst preparation methods in organic solvents, the aqueous solution impregnation-based method enables large-scale preparation of carbon-supported platinum-based alloy catalysts while reducing preparation costs.

[0044] According to embodiments of this disclosure, calcination and annealing include: first heating the precursor mixture to a calcination temperature of 600°C to 1100°C at a rate of 0.5 to 5°C / min, holding the reaction at that temperature for 0.5 to 2 h, then cooling to an annealing temperature of 450°C to 700°C at a rate of 0.1 to 3°C / min, and finally cooling to room temperature to obtain a carbon-supported platinum-based alloy catalyst.

[0045] According to embodiments of this disclosure, the heating rate can be, for example, 0.5 °C / min, 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min, etc. A suitable calcination heating rate helps control the size of platinum-based alloy nanoparticles. When the heating rate is too fast during calcination, the growth rate of platinum-based alloy nanoparticles is easily too fast, thereby affecting the size of the platinum-based alloy nanoparticles and the activity of the catalyst in the catalytic process; when the heating rate is too slow during calcination, the heating time will be prolonged, wasting energy and time. The calcination temperature can be, for example, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C, 1100 °C, etc., preferably 800~1100 °C, more preferably 900~1100 °C. Higher calcination temperatures are beneficial for the formation of highly alloyed platinum-based alloy nanoparticles. However, excessively high calcination temperatures (above 1100 °C) can easily lead to sintering and carbon deposition of nanoparticles in the catalyst, resulting in a decrease in the exposed active surface area of ​​the nanoparticles and a reduction in catalytic activity. Conversely, excessively low calcination temperatures (below 600 °C) can lead to incomplete precursor reduction and alloying, resulting in a decrease in the non-precious metal loading in the alloy nanoparticles, which is detrimental to the formation of highly alloyed alloys and intermetallic compounds. The holding time can be, for example, 0.5 h, 1 h, 0.5 h, 2 h, etc., preferably 1–2 h.

[0046] According to embodiments of this disclosure, the cooling rate can be, for example, 0.1 °C / min, 0.5 °C / min, 1 °C / min, 2 °C / min, 3 °C / min, etc., and the annealing cooling rate will affect the structure of platinum-based alloy nanoparticles. When the annealing cooling rate is too fast, the interatomic arrangement in the platinum-based alloy nanoparticles may not have enough time to complete, resulting in a decrease in the proportion of ordered alloys, thereby affecting the activity in the catalytic process; when the annealing cooling rate is too slow, the holding time will be prolonged, wasting energy and time. The annealing temperature can be, for example, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, etc., preferably 480-650 °C, more preferably 500-600 °C. Lower annealing temperatures are conducive to the formation of highly ordered platinum-based alloy nanoparticles; however, excessively low annealing temperatures (below 400 °C) can lead to difficulties in the diffusion between atoms in the alloy nanoparticles, making it impossible to control the formation of small-sized ordered alloy nanoparticles; when the annealing temperature is above 700 °C, the already formed ordered alloy nanoparticles are easily transformed into disordered alloy nanoparticles, resulting in a decrease in the ordered alloy loading in the alloy nanoparticles.

[0047] According to another embodiment of this disclosure, a carbon-supported platinum-based alloy catalyst prepared by the above preparation method is provided. The catalyst includes a carbon-based support and platinum-based alloy nanoparticles supported on the surface of the carbon-based support; wherein the platinum-based alloy nanoparticles are an alloy of platinum and non-precious metals.

[0048] According to embodiments of this disclosure, the carbon-supported platinum-based alloy catalyst prepared by the method of this disclosure has a high metal loading and a small platinum alloy nanoparticle size. Furthermore, the platinum alloy nanoparticles contained in this catalyst can form ordered alloys with superior catalytic performance, i.e., intermetallic compounds.

[0049] According to embodiments of this disclosure, the size of the platinum-based alloy nanoparticles is 3-10 nm, for example, 3 nm, 5 nm, 7 nm, 9 nm, 10 nm, etc., preferably 3-5 nm. The platinum-based alloy content in the catalyst is 40%-70%, for example, 40%, 50%, 55%, 60%, 65%, 70%, etc., preferably 50%-70%. Within this size and content range, the utilization rate of platinum atoms is high, reducing the consumption of precious metals, and ensuring that the catalyst has a large electrochemical active surface area and intrinsic activity per unit area. This synergistic optimization of size and content allows the prepared platinum-based alloy catalyst to maintain excellent catalytic performance while also exhibiting good economic benefits and industrial application prospects.

[0050] According to embodiments of this disclosure, the proportion of ordered alloy in the platinum and non-precious metal alloy is 30% to 50%, for example, it can be 30%, 35%, 40%, 45%, 50%, etc. The carbon-supported platinum-based alloy catalyst prepared by this disclosure has a high proportion of ordered alloy. The ordered alloy structure has a regular atomic arrangement and a fixed elemental composition, which can form better active sites on the catalyst surface, thereby significantly enhancing the catalyst's adsorption and activation ability for reactants and improving the catalyst's catalytic reaction efficiency.

[0051] According to another aspect of this disclosure, the application of the above-described carbon-supported platinum-based alloy catalyst in oxygen reduction reactions is provided.

[0052] According to embodiments of this disclosure, the carbon-supported platinum-based alloy catalyst exhibits high metal loading and small alloy particle size. In practical applications, this catalyst can be widely used in oxygen reduction reactions (ORR), specifically in the cathode reaction of fuel cells. When oxygen passes through the cathode of the fuel cell, it contacts the carbon-supported platinum-based alloy catalyst on the cathode and undergoes a reduction reaction. The platinum-based alloy nanoparticles, acting as active sites, can rapidly adsorb and activate oxygen molecules, promoting their combination with electrons and protons, thereby facilitating the oxygen reduction reaction.

[0053] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and accompanying drawings. Unless otherwise specified, specific techniques or conditions in the embodiments are conventional methods and can be performed according to the techniques or conditions described in the literature in this field or according to the product instructions. It should be noted that, unless otherwise specified, the methods provided in this disclosure are conventional methods, and the reactants and reagents are readily available from publicly available commercial sources.

[0054] Example 1:

[0055] Example 1 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, the specific steps of which are as follows:

[0056] Take 90 mg of cobalt chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate and add them to a 150 mL round-bottom flask. Dissolve them in high-purity water and sonicate to obtain 50 mL of impregnation solution.

[0057] Disperse 50 mg of commercial carbon black Ketjenblack-600JD in the impregnation solution, mix thoroughly by ultrasonication, and let stand for 10 h.

[0058] A round-bottom flask was connected to a rotary evaporator via a converter. Most of the moisture was removed using the rotary evaporator, yielding a black, mud-like solid. This black, mud-like solid was then rapidly cooled to freeze. The frozen black, mud-like solid was then freeze-dried overnight to obtain a black powder.

[0059] The black powder was transferred to a ceramic boat, which was then placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace, and a mixed gas containing 5% hydrogen, 5% carbon monoxide, and 90% argon was introduced into the quartz tube for 30 minutes to remove any residual air inside the tube.

[0060] In a mixed atmosphere, the tube furnace was heated to 950 °C at a heating rate of 1 °C / min, held at that temperature for 2 h, and then cooled to 600 °C at a rate of 0.5 °C / min. The furnace was then allowed to cool naturally to room temperature to obtain a carbon-supported platinum-cobalt (PtCo) alloy catalyst, wherein the loading of platinum-cobalt alloy was approximately 65%.

[0061] Figure 1 This is a high-angle annular dark-field image obtained by atomic-resolution scanning transmission electron microscopy of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure.

[0062] like Figure 1 As shown, it can be observed that the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1 contains an ordered platinum-cobalt alloy.

[0063] Figure 2 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure, obtained using a scanning transmission electron microscope. Figure 3 This is a particle size distribution diagram of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure.

[0064] like Figure 2 and Figure 3 As shown, it can be observed that the average diameter of the platinum-cobalt alloy nanoparticles in the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1 is approximately 4 nm, wherein... Figure 2 The numbers in the table represent the number of platinum-cobalt alloy nanoparticles.

[0065] Figure 4 The X-ray diffraction pattern is shown in Example 1 of this disclosure.

[0066] like Figure 4 As shown, the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1 contains an ordered platinum-cobalt alloy, and its crystal size along the (111) crystal plane can be calculated to be about 4 nm according to the Scherrer formula.

[0067] Catalytic oxygen reduction reaction was tested on a commercially available platinum-carbon catalyst (40% platinum loading) and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 under the same loading conditions. The specific test procedure was as follows: In an electrolytic cell, 0.1 M perchloric acid was used as the electrolyte, and oxygen was continuously introduced into the electrolyte to maintain oxygen saturation. The commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 were respectively dropped onto a glassy carbon electrode. The relationship between the current density and the electrode potential for oxygen reduction catalyzed by the commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 was tested using linear sweep voltammetry.

[0068] Figure 5 The graphs show the polarization curves of the oxygen reduction reaction catalyzed by commercially available platinum-carbon catalysts and the carbon-supported platinum-cobalt alloy catalyst in Example 1 of this disclosure under the same loading conditions.

[0069] like Figure 5 As shown, the performance of the carbon-supported platinum-cobalt alloy catalyst in Example 1 for catalyzing oxygen reduction reaction is significantly higher than that of commercially available platinum-carbon catalysts.

[0070] Example 2:

[0071] Example 2 provides a method for preparing a carbon-supported platinum-nickel (PtNi) alloy catalyst, the specific steps of which are as follows:

[0072] Take 95 mg of nickel chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate and add them to a 150 mL round-bottom flask. Dissolve them in high-purity water and mix them by sonication to obtain 50 mL of impregnation solution.

[0073] Disperse 50 mg of commercial Ketjenblack-600JD carbon black in the impregnation solution, mix it evenly by ultrasonication, and let it stand for 10 h.

[0074] A round-bottom flask was connected to a rotary evaporator via a conversion connector. Most of the moisture was removed using the rotary evaporator, yielding a black, mud-like solid. This black mud-like solid was then rapidly cooled to freeze. The frozen black mud-like solid was then freeze-dried overnight to obtain a black powder.

[0075] The black powder was transferred to a ceramic boat and placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace and a mixed gas with a hydrogen content of 5%, a carbon monoxide content of 10%, and an argon content of 85% was introduced into the quartz tube for 30 minutes to remove any residual air in the tube.

[0076] In a mixed atmosphere, the tube furnace was heated to 1100 °C at a heating rate of 1 °C / min, held at that temperature for 2 h, and then cooled to 600 °C at a rate of 3 °C / min. Subsequently, it was naturally cooled to room temperature to obtain a carbon-supported platinum-nickel (PtNi) alloy catalyst.

[0077] Figure 6 The image shows the X-ray diffraction pattern of the carbon-supported platinum-nickel alloy catalyst in Example 2 of this disclosure.

[0078] like Figure 6 As shown, the carbon-supported platinum-nickel alloy catalyst prepared in Example 2 contains an ordered platinum-nickel alloy, and the crystal size of its (111) crystal plane can be calculated to be about 5 nm according to the Scherrer formula.

[0079] Example 3:

[0080] Example 3 provides a method for preparing a carbon-supported platinum-cobalt (Pt3Co) alloy catalyst, the specific steps of which are as follows:

[0081] Take 32 mg of cobalt chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate and add them to a 150 mL round-bottom flask. Dissolve them in high-purity water and sonicate to obtain 50 mL of impregnation solution.

[0082] Disperse 50 mg of commercial Ketjenblack-600JD carbon black in the impregnation solution, mix it evenly by ultrasonication, and let it stand for 10 h.

[0083] A round-bottom flask was connected to a rotary evaporator via a conversion connector. Most of the moisture was removed using the rotary evaporator, yielding a black, mud-like solid. This black mud-like solid was then rapidly cooled to freeze. The frozen black mud-like solid was then freeze-dried overnight to obtain a black powder.

[0084] The black powder was transferred to a ceramic boat and placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace and a mixed gas with a hydrogen content of 5%, a carbon monoxide content of 5%, and an argon content of 90% was introduced into the quartz tube. The gas was continuously introduced for 30 minutes to remove any residual air in the tube.

[0085] In a mixed atmosphere, the tube furnace was heated to 1100 °C at a heating rate of 1 °C / min, held at that temperature for 2 h, and then cooled to 600 °C at a rate of 0.5 °C / min. Subsequently, it was naturally cooled to room temperature to obtain a carbon-supported platinum-cobalt (Pt3Co) alloy catalyst.

[0086] Example 4:

[0087] Example 4 provides a method for preparing a carbon-supported platinum-copper (PtCu) alloy catalyst, which differs from Example 3 in that: 75 mg of copper chloride dihydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, resulting in the preparation of the carbon-supported platinum-copper (PtCu) alloy catalyst.

[0088] Example 5

[0089] Example 5 provides a method for preparing a carbon-supported platinum-copper (PtCu) alloy catalyst, which differs from Example 3 in that: 69 mg of copper chloride dihydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, resulting in the preparation of the carbon-supported platinum-copper (PtCu) alloy catalyst.

[0090] Example 6

[0091] Example 6 provides a method for preparing a carbon-supported platinum-zinc (Pt3Zn) alloy catalyst, which differs from Example 3 in that: 92 mg of zinc nitrate hexahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, resulting in the preparation of the carbon-supported platinum-zinc (Pt3Zn) alloy catalyst.

[0092] Example 7

[0093] Example 7 provides a method for preparing a carbon-supported platinum-iron (PtFe) alloy catalyst, which differs from Example 3 in that: 105 mg of ferric nitrate nonahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, thus preparing the carbon-supported platinum-iron (PtFe) alloy catalyst.

[0094] Example 8

[0095] Example 8 provides a method for preparing a carbon-supported platinum-iron (Pt3Fe) alloy catalyst, which differs from Example 3 in that: 40 mg of ferric nitrate nonahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, resulting in the preparation of the carbon-supported platinum-iron (Pt3Fe) alloy catalyst.

[0096] Example 9

[0097] Example 9 provides a method for preparing a carbon-supported platinum-manganese (PtMn) alloy catalyst, which differs from Example 3 in that: 63 mg of manganese chloride and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, thus preparing the carbon-supported platinum-manganese (PtMn) alloy catalyst.

[0098] Example 10

[0099] Example 10 provides a method for preparing a carbon-supported platinum-chromium (Pt3Cr) alloy catalyst, which differs from Example 3 in that: 30 mg of chromium chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, resulting in the preparation of the carbon-supported platinum-chromium (Pt3Cr) alloy catalyst.

[0100] Example 11

[0101] Example 11 provides a method for preparing a carbon-supported platinum-vanadium (Pt3V) alloy catalyst, which differs from Example 3 in that: 20 mg of vanadium chloride and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL round-bottom flask, dissolved in high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. All other preparation processes are the same as in Example 3, thus obtaining the carbon-supported platinum-vanadium (Pt3V) alloy catalyst.

[0102] Comparative Example 1

[0103] Comparative Example 1 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst. The difference from Example 1 is that a mixed gas with a hydrogen content of 5% and an argon content of 95% is introduced into a quartz tube to prepare the carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0104] Figure 7 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 of this disclosure, obtained by atomic-resolution scanning transmission electron microscopy.

[0105] like Figure 7 As shown, it can be observed that the nanoparticles in the carbon-supported platinum-cobalt alloy catalyst of Comparative Example 1 have a relatively large particle size of about 50 nm.

[0106] Comparative Example 2

[0107] Comparative Example 2 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst. The difference from Example 1 is that a mixed gas with a carbon monoxide content of 5% and an argon content of 95% is introduced into a quartz tube to prepare the carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0108] Figure 8 This is a bright-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 2 of this disclosure, obtained using a transmission electron microscope.

[0109] like Figure 8 As shown, it can be observed that the nanoparticles in the carbon-supported platinum-cobalt alloy catalyst of Comparative Example 2 have a relatively large particle size, approximately 100 nm.

[0110] Comparative Example 3

[0111] Comparative Example 3 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst. The difference from Example 1 is that a mixed gas with a carbon monoxide content of 15%, a hydrogen content of 5%, and an argon content of 80% is introduced into a quartz tube to prepare the carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0112] Figure 9 This is a bright-field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3 of this disclosure, obtained using a transmission electron microscope.

[0113] like Figure 9 As shown, significant carbon deposits can be observed on the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3.

[0114] Comparative Example 4

[0115] Comparative Example 4 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst. The difference from Example 1 is that the temperature of the catalyst is increased to 550 °C in a tube furnace at a heating rate of 1 °C / min to prepare the carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0116] Figure 10 The X-ray diffraction pattern of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of this disclosure is shown.

[0117] like Figure 10 As shown, the diffraction peak position of the (111) crystal plane of the prepared PtCo alloy is significantly shifted to a lower angle compared with the ordered alloy, which proves that its alloying degree is reduced.

[0118] Comparative Example 5

[0119] Comparative Example 5 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst. The difference from Example 1 is that the temperature is lowered to 750 °C at a rate of 0.5 °C / min to prepare the carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0120] Figure 11 The X-ray diffraction pattern of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of this disclosure is shown.

[0121] like Figure 11 As shown, it can be observed that the superlattice characteristic peaks of the prepared PtCo alloy almost disappear, proving that the content of ordered alloys has decreased significantly.

[0122] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A carbon-supported platinum-based alloy catalyst, characterized in that, The catalyst comprises a carbon-based support and platinum-based alloy nanoparticles supported on the surface of the carbon-based support; wherein the platinum-based alloy nanoparticles are an alloy of platinum and non-noble metals. The size of the platinum-based alloy nanoparticles is 3~10 nm; The catalyst contains 40% to 70% platinum-based alloy. The proportion of ordered alloys in the platinum and non-precious metal alloys is 30-50%; The preparation method of the carbon-supported platinum-based alloy catalyst includes: Provide impregnation solutions containing platinum sources and non-precious metal sources; The carbon-based support is dispersed and impregnated in the impregnation solution, and the water is removed to obtain a precursor mixture; In a mixed atmosphere comprising hydrogen, carbon monoxide, and an inert gas, the precursor mixture is heated to a calcination temperature of 600 °C to 1100 °C at a rate of 0.5–5 °C / min, held at that temperature for 0.5–2 h, and then cooled to an annealing temperature of 450 °C to 700 °C at a rate of 0.1–3 °C / min. After cooling to room temperature, a carbon-supported platinum-based alloy catalyst is obtained. The hydrogen content in the mixed atmosphere is 3%–10%, the carbon monoxide content is 1%–15%, and the inert gas content is 75%–96%.

2. The carbon-supported platinum-based alloy catalyst according to claim 1, characterized in that, The platinum source includes any one of chloroplatinic acid, platinum acetylacetonate, platinum tetrahydronitrate, potassium chloroplatinate, sodium chloroplatinate, and ammonium chloroplatinate. The non-precious metal source is a soluble non-precious metal salt, which is selected from the nitrate or chloride salt of any one of vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc.

3. The carbon-supported platinum-based alloy catalyst according to claim 2, characterized in that, The molar ratio of the non-precious metal source to the platinum source is (0.3~1.5):1; The mass ratio of the carbon-based support, platinum source, and non-precious metal source is 2:(6~10):(1.2~4.5).

4. The carbon-supported platinum-based alloy catalyst according to claim 1, characterized in that, The inert gas in the mixed atmosphere includes any one of argon, helium, and nitrogen; The flow rate of the mixed atmosphere is 10~150 sccm.

5. The application of a carbon-supported platinum-based alloy catalyst according to any one of claims 1 to 4 in oxygen reduction reactions.

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