A platinum-palladium-based multi-component alloy sub-nanobelt catalyst, its preparation method and application

Abstract

The present invention provides a platinum-palladium-based multi-component alloy sub-nanobelt catalyst and its preparation method and application, belonging to the technical field of electrocatalysis of nanomaterials. The elemental composition of the platinum-palladium-based multi-component alloy sub-nanobelt catalyst of the present invention is PtPdM; the M is a non-noble metal, and the non-noble metal is one or more of Fe, Co, Ni, Ga, and Zn; in the present invention, a metal precursor solution and a reducing solution are ultrasonically mixed to obtain a mixture, and then the mixture is heated and reacted, and the product is centrifugally collected and calcined to obtain the platinum-palladium-based multi-component alloy sub-nanobelt catalyst. The synthesis method of the present invention is simple and controllable, and the obtained platinum-palladium-based multi-component alloy sub-nanobelt catalyst has the characteristics of large specific surface area, rich active sites, and low noble metal content, and at the same time exhibits excellent catalytic performance for oxygen reduction reaction in acidic electrolyte.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis of nanomaterials, and particularly relates to a platinum-palladium-based multi-alloy sub-nanobelt catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] In today's world, traditional fossil fuels are on the verge of depletion, and environmental problems such as global warming are becoming increasingly prominent. Therefore, it is urgent to develop clean energy technologies to alleviate environmental pollution and energy crises and promote the transformation of the traditional energy structure to clean energy. Hydrogen fuel cells, a typical clean energy technology that can directly convert chemical energy into electrical energy, have the characteristics of high energy conversion efficiency, good low-temperature resistance, and fast energy replenishment speed. At the same time, they can truly achieve a power supply strategy with zero product pollution and are considered one of the power sources for future transportation and various electronic products. However, the kinetics of the cathode oxygen reduction reaction (ORR) in hydrogen fuel cells is relatively slow, resulting in high overpotential losses, which greatly limits large-scale application and development. Due to its special d-orbital electron structure, Pt has good oxygen adsorption and dissociation characteristics and is currently the most widely used cathode catalyst for reducing the ORR overpotential. However, the low abundance and high price of Pt lead to a high cost of the catalyst, making it difficult to meet the requirements of large-scale commercialization of hydrogen fuel cells. At the same time, the non-optimal electron structure of Pt results in a strong binding energy with oxygen-containing substances, increasing the overpotential of the catalytic reaction, and the catalytic performance needs to be further improved. Therefore, rationally designing ORR catalyst materials, reducing the Pt dosage while improving the activity and stability of the catalyst, is the current research focus.

[0003] Currently, people mainly alloy costly noble metals (such as Pt, Pd) with one or more transition metals with rich reserves and low prices to construct PtPd-based multi-alloy catalysts with a wide range of adjustable composition ranges and electronic structures. By increasing the types of atoms in the multi-alloy, the degree of disorder of the alloy configuration can be increased, the diversity of bond lengths and coordination environments can be induced, the too strong oxygen binding energy of Pt can be improved, and the catalytic performance can be enhanced.

[0004] Common methods for preparing PtPd-based multi-alloy catalysts include carbon thermal shock method, pyrolysis method, microwave heating method, etc. However, these methods have harsh preparation conditions, and the required high-temperature conditions make the morphology of the prepared multi-alloy materials uncontrollable, and the surface active sites of the synthesized large-size zero-dimensional materials are limited. Therefore, inventing a simple, controllable, and universal low-temperature synthesis method to achieve the controllable growth of multi-alloy catalysts at the atomic scale (sub-nanoscale) is the key to realizing highly efficient ORR catalysts and is of great significance in reducing the catalyst cost and improving the catalyst performance. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst, a preparation method thereof, and an application thereof. The method of the present invention has mild preparation conditions and adjustable elemental composition. The prepared catalyst has the characteristics of large specific surface area, low noble metal content, high catalytic activity, and excellent stability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst (PtPd-based multi-element alloy sub-nanometer ribbon catalyst), with an elemental composition of PtPdM; the M is a non-noble metal, and the non-noble metal is one or more of Fe, Co, Ni, Ga, and Zn.

[0009] The elemental composition of the platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst of the present invention can be adjusted from ternary to heptavalent. For example, it can be composed of elements such as PtPdFe, PtPdFeCo, PtPdFeCoNi, PtPdFeCoNiGa, and PtPdFeCoNiGaZn.

[0010] The platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst of the present invention has a micron-scale length and a sub-nanometer-scale thickness.

[0011] Another technical solution of the present invention:

[0012] A preparation method of the platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst as described above, comprising the following steps:

[0013] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-noble metal salts in deionized water, and ultrasonically dissolve to obtain a metal precursor solution;

[0014] (2) Dissolve a reducing agent and a morphology control agent in an organic solvent, and ultrasonically obtain a reduction solution;

[0015] (3) Ultrasonically mix the metal precursor solution obtained in step (1) with the reduction solution obtained in step (2) to obtain a mixture, then heat the mixture for reaction, and then centrifuge to collect the product and perform calcination treatment to obtain the platinum-palladium-based multi-element alloy sub-nanometer ribbon catalyst.

[0016] The present invention mainly obtains a metal precursor solution by dissolving various metal salts in deionized water, and obtains a reduction solution by dissolving a reducing agent and a morphology control agent in an organic solvent. The two solutions are fully mixed, and under heating conditions, the two-dimensional controllable growth of the multi-element alloy at the atomic scale is realized; then through low-temperature calcination treatment in a reducing atmosphere, the multi-element alloy is highly crystallized to obtain a PtPd-based multi-element alloy sub-nanobelt catalyst. This catalyst has the characteristics of a large specific surface area, rich active sites, and low noble metal content, and exhibits excellent catalytic activity and stability for the oxygen reduction reaction in acidic electrolytes.

[0017] Further, in the metal precursor solution, the concentration of sodium tetrachloropalladate is 8-25 mM, the concentration of chloroplatinic acid hexahydrate is 0.5-5.0 mM, and the concentration of non-noble metal salts is 3-15 mM. When there are multiple non-noble metal salts, the concentration is the individual concentration of each non-noble metal salt.

[0018] Further, the non-noble metal salt is one or more of ferric chloride hexahydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, gallium nitrate hydrate, and zinc chloride.

[0019] Further, the reducing agent is at least two of glucose, citric acid, ascorbic acid, sodium borohydride, molybdenum hexacarbonyl, cobalt carbonyl, and tungsten hexacarbonyl, and the morphology control agent is one of polyvinylpyrrolidone, tetrabutylammonium bromide, cetyltrimethylammonium bromide, and sodium dodecylbenzenesulfonate.

[0020] Further, the organic solvent is one of ethylenediamine, diethylenetriamine, and oleylamine.

[0021] Further, in the reduction solution, the concentration of the reducing agent is 15-75 mM, and the concentration of the morphology control agent is 0.5-2.0 M. When there are multiple reducing agents or morphology control agents, the above concentrations represent the individual concentrations of each reducing agent or morphology control agent.

[0022] Further, the volume ratio of the metal precursor solution to the reduction solution is 1:(0.2-5).

[0023] Further, the temperature of the heating reaction is 90-125 °C, and the time is 4-16 h.

[0024] Further, the calcination treatment is carried out in a H2 / Ar atmosphere, heating to 150-300 °C at a rate of 5 °C / min and holding for 0.5-4.0 h.

[0025] Furthermore, the volume fraction of H2 in the H2 / Ar atmosphere is 5%.

[0026] Furthermore, the solution used for centrifugation is water and / or ethanol, the number of centrifugation times is 2 - 5 times, the centrifugation speed is 7500 - 10000 r / min, and the time is 3 - 8 min.

[0027] Aspect three of the technical solution of the present invention:

[0028] Application of the platinum-palladium-based multi-component alloy sub-nanobelt catalyst in the electrocatalytic oxygen reduction reaction.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] (1) The synthesis method of the present invention is simple and controllable, without the need for complex and expensive equipment. It can achieve the multi-component alloying of Pt and various non-precious metals, with controllable product components and strong universality.

[0031] (2) The catalyst prepared by the present invention has an ultrathin two-dimensional structure, with a thickness reaching the sub-nanometer scale, a high surface atom exposure rate, and abundant active sites, realizing the controllable construction of an atomic-scale two-dimensional multi-component alloy catalytic material.

[0032] (3) In the platinum-palladium-based multi-component alloy sub-nanobelt catalyst obtained by the present invention, the Pt atom content only accounts for 5% - 10% of the total atomic content, significantly reducing the preparation cost of the catalyst. The constructed multi-component alloy sub-nanomaterials with a wide range of adjustable composition ranges and electronic structures stimulate the diversity of active sites and achieve a significant improvement in electrocatalytic activity; at the same time, due to the formation of more bonding states between different metals, the structure of the multi-component alloy is more dense and has excellent stability. Through multi-component alloying, rich regulation of the atomic / electronic structure of the catalytic material is realized, and through atomic-scale two-dimensional structuring, a high exposure of the active sites of the catalytic material is achieved, providing important technical support for the design and preparation of new alloy materials (high entropy / medium entropy) catalysts.

[0033] (4) The platinum-palladium-based multi-component alloy sub-nanobelt catalyst obtained by the present invention exhibits excellent ORR catalytic performance in acidic electrolytes. Description of the Drawings

[0034] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0035] Figure 1 It is a transmission electron microscope (TEM) image of the PtPd-based five-component alloy sub-nanobelt catalyst prepared in Example 1 of the present invention. Among them, a is the low-magnification TEM image of the PtPd-based five-component alloy sub-nanobelt catalyst, and b is the high-magnification TEM image of the PtPd-based five-component alloy sub-nanobelt catalyst;

[0036] Figure 2 XRD patterns of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 2 of the present invention before and after calcination;

[0037] Figure 3 Comparison diagram of ORR performance of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 3 of the present invention and commercial Pt / C catalyst (Comparative Example 1) in acidic electrolyte. Among them, a is the comparison diagram of ORR performance curves of the PtPd-based quinary alloy sub-nanobelt catalyst and commercial Pt / C catalyst in 0.1M HClO4 acidic electrolyte, and b is the comparison diagram of mass activity (MA) of the PtPd-based quinary alloy sub-nanobelt catalyst and commercial Pt / C catalyst;

[0038] Figure 4 Comparison diagram of ORR performance curves of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 3 of the present invention and commercial Pt / C catalyst (Comparative Example 1) before and after 30,000 cycles in acidic electrolyte. Among them, a is the comparison diagram of ORR performance curves of the PtPd-based quinary alloy sub-nanobelt catalyst before and after 30,000 cycles, and b is the comparison diagram of ORR performance curves of commercial Pt / C catalyst before and after 30,000 cycles. Detailed implementation manners

[0039] The various exemplary implementation manners of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0040] It should be understood that the terms used in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0042] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the present invention's specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and embodiments of the present invention are merely exemplary.

[0043] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0044] An embodiment of the present invention provides a platinum-palladium-based multi-component alloy sub-nanobelt catalyst (PtPd-based multi-component alloy sub-nanobelt catalyst), with an elemental composition of PtPdM; the M is a non-precious metal, and the non-precious metal is one or more of Fe, Co, Ni, Ga, and Zn.

[0045] In the embodiment of the present invention, the elemental components of the platinum-palladium-based multi-component alloy sub-nanobelt catalyst can be adjusted from ternary to heptavalent. For example, it can be composed of elements such as PtPdFe, PtPdFeCo, PtPdFeCoNi, PtPdFeCoNiGa, PtPdFeCoNiGaZn, etc. The embodiment of the present invention takes the five-component alloy sub-nanobelt catalyst as an example for preparation, but it does not limit the technical solution of the present invention.

[0046] An embodiment of the present invention also provides a preparation method of the platinum-palladium-based multi-component alloy sub-nanobelt catalyst, including the following steps:

[0047] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-precious metal salt in deionized water, and ultrasonically dissolve to obtain a metal precursor solution;

[0048] (2) Dissolve a reducing agent and a morphology control agent in an organic solvent, and ultrasonically obtain a reducing solution;

[0049] (3) Ultrasonically mix the metal precursor solution obtained in step (1) with the reducing solution obtained in step (2) to obtain a mixture, then heat the mixture for reaction, and then centrifuge to collect the product and perform calcination treatment to obtain the platinum-palladium-based multi-component alloy sub-nanobelt catalyst.

[0050] In a preferred embodiment of the present invention, in the metal precursor solution, the concentration of sodium tetrachloropalladate is 8 - 25 mM, the concentration of chloroplatinic acid hexahydrate is 0.5 - 5.0 mM, and the concentration of non-precious metal salt is 3 - 15 mM. When there are multiple non-precious metal salts, the concentration is the individual concentration of each non-precious metal salt.

[0051] In a preferred embodiment of the present invention, the non-precious metal salt is one or more of ferric chloride hexahydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, gallium nitrate hydrate, and zinc chloride.

[0052] In a preferred embodiment of the present invention, the reducing agent is at least two of glucose, citric acid, ascorbic acid, sodium borohydride, molybdenum hexacarbonyl, cobalt carbonyl and tungsten hexacarbonyl, and the morphology control agent is one of polyvinylpyrrolidone, tetrabutylammonium bromide, cetyltrimethylammonium bromide and sodium dodecylbenzenesulfonate.

[0053] In a preferred embodiment of the present invention, the organic solvent is one of ethylenediamine, diethylenetriamine and oleylamine.

[0054] In a preferred embodiment of the present invention, the concentration of the reducing agent in the reduction solution is 15 - 75 mM, and the concentration of the morphology control agent is 0.5 - 2.0 M. When there are multiple reducing agents or morphology control agents, the above concentrations represent the individual concentrations of each reducing agent or morphology control agent.

[0055] In a preferred embodiment of the present invention, the volume ratio of the metal precursor solution to the reduction solution is 1:(0.2 - 5).

[0056] In a preferred embodiment of the present invention, the temperature of the heating reaction is 90 - 125 °C, and the time is 4 - 16 h.

[0057] In a preferred embodiment of the present invention, the calcination treatment is carried out in a H2 / Ar atmosphere, heating to 150 - 300 °C at a rate of 5 °C / min and holding for 0.5 - 4.0 h.

[0058] In a preferred embodiment of the present invention, the volume fraction of H2 in the H2 / Ar atmosphere is 5%.

[0059] In a preferred embodiment of the present invention, the solution for centrifugation is water and / or ethanol, the number of centrifugation times is 2 - 5 times, the centrifugation speed is 7500 - 10000 r / min, and the time is 3 - 8 min.

[0060] All raw materials used in the embodiments of the present invention are commercially available.

[0061] The technical solution of the present invention will be further described below through examples.

[0062] Example 1

[0063] A preparation method of a PtPdFeCoNi quinary alloy sub-nanobelt catalyst includes the following steps:

[0064] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-noble metal salts (ferric chloride hexahydrate, cobalt chloride hexahydrate, and nickel chloride hexahydrate) in a centrifuge tube filled with deionized water, and ultrasonicate for 60 min to obtain a metal precursor solution. In the metal precursor solution, the concentration of sodium tetrachloropalladate is 25 mM, the concentration of chloroplatinic acid hexahydrate is 5 mM, the concentration of ferric chloride hexahydrate is 10 mM, the concentration of cobalt chloride hexahydrate is 12 mM, and the concentration of nickel chloride hexahydrate is 15 mM;

[0065] (2) Dissolve glucose, cobalt carbonyl, and tetrabutylammonium bromide in a diethylenetriamine solvent, and ultrasonicate for 90 min to obtain a reducing solution. In the reducing solution, the concentration of glucose is 70 mM, the concentration of cobalt carbonyl is 40 mM, and the concentration of tetrabutylammonium bromide is 2.0 M;

[0066] (3) Mix the metal precursor solution obtained in step (1) with the reducing solution obtained in step (2) at a volume ratio of 1:5. After ultrasonically mixing evenly for 60 min, a mixture is obtained. Then, heat the mixture at 90 °C for 16 h. Wash the reacted solution with water and ethanol respectively and centrifuge twice at a centrifugal speed of 7500 r / min for 8 min. After drying, collect the centrifuged product. Then, in a 5% H2 / Ar atmosphere, heat it to 150 °C at a rate of 5 °C / min and hold for 4.0 h to obtain a PtPdFeCoNi quinary alloy sub-nanobelt catalyst.

[0067] Example 2

[0068] A preparation method of a PtPdCoNiZn quinary alloy sub-nanobelt catalyst, comprising the following steps:

[0069] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-noble metal salts (cobalt chloride hexahydrate, nickel chloride hexahydrate, and zinc chloride) in a centrifuge tube filled with deionized water, and ultrasonicate for 10 min to obtain a metal precursor solution. In the metal precursor solution, the concentration of sodium tetrachloropalladate is 8 mM, the concentration of chloroplatinic acid hexahydrate is 0.5 mM, the concentration of cobalt chloride hexahydrate is 3 mM, the concentration of nickel chloride hexahydrate is 5 mM, and the concentration of zinc chloride is 4 mM;

[0070] (2) Dissolve sodium borohydride, hexacarbonylmolybdenum, and cetyltrimethylammonium bromide in an ethylenediamine solvent, and ultrasonicate for 10 min to obtain a reducing solution. In the reducing solution, the concentration of sodium borohydride is 15 mM, the concentration of hexacarbonylmolybdenum is 75 mM, and the concentration of cetyltrimethylammonium bromide is 0.5 M;

[0071] (3) Mix the metal precursor solution obtained in step (1) and the reducing solution obtained in step (2) at a volume ratio of 1:0.2. After ultrasonic mixing for 20 min to make it fully mixed evenly, a mixture is obtained. Then, heat the mixture at 125 °C for 4 h. Wash the reacted solution with water and ethanol respectively and centrifuge it 5 times. The centrifugation speed is 10,000 r / min and the time is 3 min. After drying, collect the obtained product. In a 5% H2 / Ar atmosphere, heat it to 300 °C at a rate of 5 °C / min and hold for 0.5 h to obtain a PtPdCoNiZn quinary alloy sub-nanobelt catalyst.

[0072] Example 3

[0073] A preparation method of a PtPdCoGaZn quinary alloy sub-nanobelt catalyst, comprising the following steps:

[0074] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate and non-noble metal salts (cobalt chloride hexahydrate, gallium nitrate hydrate and zinc chloride) in a centrifuge tube filled with deionized water, and ultrasonically mix for 30 min to obtain a metal precursor solution. In the metal precursor solution, the concentration of sodium tetrachloropalladate is 15 mM, the concentration of chloroplatinic acid hexahydrate is 3 mM, the concentration of cobalt chloride hexahydrate is 10 mM, the concentration of gallium nitrate hydrate is 10 mM, and the concentration of zinc chloride is 10 mM;

[0075] (2) Dissolve citric acid, cobalt carbonyl and sodium dodecylbenzenesulfonate in an ethylenediamine solvent, and ultrasonically mix for 60 min to obtain a reducing solution. In the reducing solution, the concentration of citric acid is 40 mM, the concentration of cobalt carbonyl is 60 mM, and the concentration of sodium dodecylbenzenesulfonate is 1.2 M;

[0076] (3) Mix the metal precursor solution obtained in step (1) and the reducing solution obtained in step (2) at a volume ratio of 1:3. After ultrasonic mixing for 50 min to make it fully mixed evenly, a mixture is obtained. Then, heat the mixture at 110 °C for 10 h. Wash the reacted solution with water and ethanol respectively and centrifuge it 4 times. The centrifugation speed is 9,000 r / min and the time is 5 min. After drying, collect the obtained product. In a 5% H2 / Ar atmosphere, heat it to 200 °C at a rate of 5 °C / min and hold for 2 h to obtain a PtPdCoGaZn quinary alloy sub-nanobelt catalyst.

[0077] Example 4

[0078] A preparation method of a PtPdFeNiGa quinary alloy sub-nanobelt catalyst, comprising the following steps:

[0079] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-noble metal salts (ferric chloride hexahydrate, gallium nitrate hydrate, and nickel chloride hexahydrate) in a centrifuge tube filled with deionized water, and ultrasonicate for 20 min to obtain a metal precursor solution. In the metal precursor solution, the concentration of sodium tetrachloropalladate is 12 mM, the concentration of chloroplatinic acid hexahydrate is 4 mM, the concentration of ferric chloride hexahydrate is 6 mM, the concentration of gallium nitrate hydrate is 10 mM, and the concentration of nickel chloride hexahydrate is 6 mM;

[0080] (2) Dissolve ascorbic acid, molybdenum hexacarbonyl, and polyvinylpyrrolidone in an ethylenediamine solvent, and ultrasonicate for 40 min to obtain a reducing solution. In the reducing solution, the concentration of ascorbic acid is 30 mM, the concentration of molybdenum hexacarbonyl is 50 mM, and the concentration of polyvinylpyrrolidone is 1.5 M;

[0081] (3) Mix the metal precursor solution obtained in step (1) with the reducing solution obtained in step (2) at a volume ratio of 1:2. After ultrasonically mixing evenly for 30 min to obtain a mixture, then heat the mixture at 120 °C for 8 h. Wash and centrifuge the reacted solution 3 times each with water and ethanol, with a centrifuge speed of 8000 r / min and a time of 3 min. After drying, collect the obtained product and heat it from room temperature to 250 °C at a rate of 5 °C / min and hold for 1 h in a 5% H2 / Ar atmosphere to obtain a PtPdFeNiGa quinary alloy sub-nanobelt catalyst.

[0082] Example 5

[0083] A preparation method of a PtPdNiGaZn quinary alloy sub-nanobelt catalyst, comprising the following steps:

[0084] (1) Dissolve sodium tetrachloropalladate, chloroplatinic acid hexahydrate, and non-noble metal salts (zinc chloride hydrate, gallium nitrate hydrate, and nickel chloride hexahydrate) in a centrifuge tube filled with deionized water, and ultrasonicate for 40 min to obtain a metal precursor solution. In the metal precursor solution, the concentration of sodium tetrachloropalladate is 20 mM, the concentration of chloroplatinic acid hexahydrate is 4 mM, the concentration of zinc chloride hydrate is 15 mM, the concentration of gallium nitrate hydrate is 15 mM, and the concentration of nickel chloride hexahydrate is 15 mM;

[0085] (2) Dissolve citric acid, molybdenum hexacarbonyl, and cetyltrimethylammonium bromide in an oleylamine solvent, and ultrasonicate for 80 min to obtain a reducing solution. In the reducing solution, the concentration of citric acid is 60 mM, the concentration of molybdenum hexacarbonyl is 70 mM, and the concentration of cetyltrimethylammonium bromide is 1.8 M;

[0086] (3) Mix the metal precursor solution obtained in step (1) and the reducing solution obtained in step (2) at a volume ratio of 1:1. After ultrasonic mixing for 40 min to make it fully mixed evenly, a mixture is obtained. Then, heat the mixture at 100 °C for 12 h. Wash and centrifuge the reacted solution twice with water and ethanol respectively. The centrifugation speed is 8500 r / min and the time is 4 min. After drying, collect the obtained product. In a 5% H2 / Ar atmosphere, heat it to 220 °C at a rate of 5 °C / min and hold for 3 h to obtain the PtPdNiGaZn quinary alloy sub-nanobelt catalyst.

[0087] Comparative Example 1

[0088] Commercial Pt / C catalyst (purchased from Suzhou Yilongsheng Energy Technology Co., Ltd.).

[0089] Performance test

[0090] Figure 1 This is the transmission electron microscopy (TEM) image of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 1 of the present invention. Among them, a is the low-magnification TEM image of the PtPd-based quinary alloy sub-nanobelt catalyst, and b is the high-magnification TEM image of the PtPd-based quinary alloy sub-nanobelt catalyst. It can be seen that the prepared PtPd-based quinary alloy sub-nanobelt catalyst has a micron-level length and a sub-nanometer-level thickness of 0.7 - 1.0 nm.

[0091] Figure 2 This is the X-ray diffraction (XRD) pattern of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 2 of the present invention before and after calcination. It can be seen that the PtPd-based quinary alloy sub-nanobelt catalyst has poor crystallinity before calcination, and after low-temperature calcination, the PtPd-based quinary alloy sub-nanobelt catalyst has a face-centered cubic phase structure with high crystallinity and no segregation phenomenon.

[0092] Figure 3 This is the comparison chart of the ORR performance of the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 3 of the present invention and the commercial Pt / C catalyst (Comparative Example 1) in acidic electrolyte. Among them, a is the comparison chart of the ORR performance curves of the PtPd-based quinary alloy sub-nanobelt catalyst and the commercial Pt / C catalyst in 0.1 M HClO4 acidic electrolyte. It can be seen that the half-wave potential of the PtPd-based quinary alloy sub-nanobelt catalyst can reach 0.90 V (relative to the standard hydrogen potential), which is higher than the half-wave potential of the commercial Pt / C of 0.85 V; b is the comparison chart of the mass activity (MA) of the PtPd-based quinary alloy sub-nanobelt catalyst and the commercial Pt / C catalyst. It can be seen that the mass activity of the PtPd-based quinary alloy sub-nanobelt catalyst at 0.9 V is 3.02 A / mg Pt , which is that of the commercial Pt / C (0.18 A / mg Pt)16.8 times. This proves that the PtPd-based quinary alloy sub-nanobelt catalyst prepared in the embodiment of the present invention has excellent acidic ORR activity in acidic electrolyte.

[0093] Figure 4 It is a comparison chart of ORR performance curves before and after 30,000 cycles in acidic electrolyte for the PtPd-based quinary alloy sub-nanobelt catalyst prepared in Example 3 of the present invention and commercial Pt / C catalyst (Comparative Example 1). Among them, b is the comparison chart of ORR performance curves of the commercial Pt / C catalyst before and after 30,000 cycles. It can be seen that after 30,000 cycles, the half-wave potential of the commercial Pt / C catalyst is 0.80V, with a decay of 0.05V compared with that before the cyclic test. a is the comparison chart of ORR performance curves of the PtPd-based quinary alloy sub-nanobelt catalyst before and after 30,000 cycles. It can be seen that after 30,000 cycles, the half-wave potential of the PtPd-based quinary alloy sub-nanobelt catalyst still remains at 0.88V, with a decay of only 0.02V compared with that before the cyclic test. This proves that the PtPd-based quinary alloy sub-nanobelt catalyst prepared in the present invention has relatively excellent ORR stability.

[0094] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A platinum-palladium-based multi-element alloy sub-nanobelt catalyst, characterized in that: The elemental composition is PtPdM; The M is a non-precious metal, and the non-precious metal is one or more of Fe, Co, Ni, Ga and Zn; The preparation method of the platinum-palladium-based multi-element alloy sub-nanobelt catalyst comprises the following steps: (1) dissolving sodium tetrachloropalladate, chloroplatinic acid hexahydrate and a non-precious metal salt in deionized water, and dissolving by ultrasonication to obtain a metal precursor solution; in the metal precursor solution, the concentration of sodium tetrachloropalladate is 8 to 25 mM, the concentration of chloroplatinic acid hexahydrate is 0.5 to 5.0 mM, and the concentration of the non-precious metal salt is 3 to 15 mM; (2) dissolving a reducing agent and a morphology control agent in an organic solvent and performing ultrasonic treatment to obtain a reducing solution; (3) ultrasonically mixing the metal precursor solution obtained in step (1) and the reducing solution obtained in step (2) to obtain a mixture, then heating the mixture for reaction, then collecting the product by centrifugation and calcining it to obtain the platinum-palladium-based multi-element alloy sub-nanobelt catalyst; The calcination treatment is carried out in a H2 / Ar atmosphere, with the temperature being raised to 150-300°C at a rate of 5°C / min and kept at that temperature for 0.5-4.0h.

2. The platinum-palladium-based multi-element alloy sub-nanobelt catalyst according to claim 1, characterized in that: The non-noble metal salt is one or more of ferric chloride hexahydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, hydrated gallium nitrate and zinc chloride.

3. The platinum-palladium based multi-element alloy sub-nanobelt catalyst according to claim 1, characterized in that: The reducing agent is at least two of glucose, citric acid, ascorbic acid, sodium borohydride, molybdenum hexacarbonyl, cobalt carbonyl and tungsten hexacarbonyl; the morphology control agent is one of polyvinyl pyrrolidone, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide and sodium dodecylbenzene sulfonate; and the organic solvent is one of ethylenediamine, diethylenetriamine and oleylamine.

4. The platinum-palladium based multi-element alloy sub-nanobelt catalyst according to claim 1, characterized in that: The concentration of the reducing agent in the reducing solution is 15-75 mM, and the concentration of the morphology controlling agent is 0.5-2.0 M.

5. The platinum-palladium based multi-element alloy sub-nanobelt catalyst according to claim 1, characterized in that: The volume ratio of the metal precursor solution to the reducing solution is 1:(0.2-5).

6. The platinum-palladium based multi-element alloy sub-nanobelt catalyst according to claim 1, characterized in that: The heating reaction temperature is 90-125°C and the time is 4-16 hours; and / or, The centrifugal solution is water and / or ethanol, the number of centrifugation is 2 to 5 times, the centrifugal speed is 7500 to 10000 r / min, and the time is 3 to 8 minutes.

7. Use of the platinum-palladium-based multi-element alloy sub-nanobelt catalyst as described in any one of claims 1 to 6 in an electrocatalytic oxygen reduction reaction.

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