Graphitized nanocarbon cage containing phosphorus element, method for preparing same, and platinum-carbon catalyst and method for preparing and using same

Abstract

The present application relates to the field of fuel cell, discloses a kind of phosphorus-containing graphitized nanocarbon cage and its preparation method and platinum carbon catalyst and its preparation method and application, the phosphorus-containing graphitized nanocarbon cage has the structure of hollow cage with diameter 2-100nm, and the phosphorus atom molar percentage content measured using XPS is 0.5-10%.The phosphorus-containing graphitized nanocarbon cage provided by the present application is made into platinum carbon catalyst, which is beneficial to improve its oxygen reduction reaction (ORR) activity and stability as fuel cell catalyst (Pt / C catalyst).

Description

Technical Field

[0001] This invention relates to the field of fuel cells, specifically to graphitized carbon nanocages containing phosphorus and their preparation methods, and platinum-carbon catalysts and their preparation methods and applications. Background Technology

[0002] A fuel cell is a power generation device that converts the chemical energy of fuel into electrical energy directly through an electrochemical reaction without combustion. It has advantages such as high energy density, fast start-up, and high energy conversion efficiency, and is considered one of the most promising power generation technologies.

[0003] Currently, platinum-carbon catalysts (Pt / C) are the most widely used catalysts in fuel cells. Commercially, 40% Pt / C catalysts are prepared by reducing chloroplatinic acid impregnated inside and on the surface of Vulcan XC-72 carbon black into platinum nanoparticles via chemical reduction. However, during use, the significant decrease in platinum surface area due to platinum dissolution and agglomeration greatly affects the lifespan of the Pt / C catalyst. Therefore, developing catalysts with high catalytic activity and stability is of great value for reducing costs and promoting the practical application of fuel cell technology.

[0004] Carbon nanocages are hollow carbon nanomaterials coated with graphite layers. Their surface structure resembles porous carbon, with pore sizes ranging from 2-100 nm and generally large specific surface areas. Due to their low density, high specific surface area, unique porous structure, strong corrosion resistance, and good electrical conductivity, they have recently shown exceptionally promising applications as catalyst supports, attracting widespread research. To improve the performance of carbon nanomaterials and adapt them to various applications, researchers often introduce heteroatoms (such as oxygen and nitrogen atoms) into them to enhance their performance. Although significant progress has been made in the research on the doping modification and properties of carbon nanomaterials, consensus has not yet been reached on some fundamental issues, and further in-depth research is needed on doped carbon nanomaterials, their preparation methods, and catalytic performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of low specific activity and poor electrochemical stability of Pt / C catalysts in the prior art, and to provide a graphitized carbon nanocage containing phosphorus and its preparation method, as well as a platinum-carbon catalyst and its preparation method and application. Using the graphitized carbon nanocage containing phosphorus provided by this invention as a support, combined with the noble metal platinum, the catalytic activity of the catalyst can be improved and it has better electrochemical stability.

[0006] The inventors of this invention discovered during their research that doping with phosphorus atoms in nano-carbon cages can distort the carbon lattice in carbon materials, increasing the number of defect sites. These increased defect sites often have higher electron cloud density, thus enhancing conductivity. Furthermore, the introduction of phosphorus atoms can further modify the structure of carbon materials, resulting in specific ranges of pores and surface structures. The heteroatom functional groups on the modified carbon materials can adjust the charge distribution of the supported metal active components, promote the stability and dispersion of the metal components, and inhibit the aggregation of metal particles, thereby improving the catalyst's lifetime and catalytic effect.

[0007] To achieve the above objectives, the first aspect of the present invention provides a graphitized carbon nanocage containing phosphorus, wherein the graphitized carbon nanocage containing phosphorus has a hollow cage-like structure with a diameter of 2-100 nm and a phosphorus atom molar percentage content of 0.5-10% as measured by XPS.

[0008] Preferably, the graphitized carbon nanocage containing phosphorus contains carbon, oxygen, and phosphorus. X-ray photoelectron spectroscopy shows that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus is 50-95%, the molar percentage of phosphorus is 0.5-10%, and the molar percentage of oxygen is 3-40%.

[0009] More preferably, the graphitized carbon nanocage further contains nitrogen, and X-ray photoelectron spectroscopy shows that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus is 50-95%, the molar percentage of phosphorus is 0.5-10%, the molar percentage of oxygen is 3-40%, and the molar percentage of nitrogen is 0.5-8%; even more preferably, X-ray photoelectron spectroscopy shows that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus is 55-88%, the molar percentage of phosphorus is 1-9%, the molar percentage of oxygen is 10-35%, and the molar percentage of nitrogen is 0.5-3%.

[0010] A second aspect of the present invention provides a method for preparing graphitized carbon nanocages containing phosphorus, the method comprising the following steps:

[0011] (1) Provide a solution containing a transition metal salt, a carbon source and a solvent, and then dry it to obtain a precursor;

[0012] (2) Under an inert or reducing atmosphere, the precursor obtained in step (1) is subjected to high-temperature pyrolysis, preferably at a temperature of 850-1300℃, to obtain pyrolysis products.

[0013] (3) The pyrolysis product is acid washed, then solid-liquid separation and drying are performed to obtain nano-carbon cages;

[0014] (4) The nano carbon cage is mixed with a phosphorus source and then subjected to high-temperature treatment at 300-1500℃.

[0015] In a preferred embodiment, the phosphorus source contains nitrogen. Using this preferred embodiment, by simultaneously incorporating phosphorus and nitrogen into the nano-carbon cage using a phosphorus source, the resulting graphitized nano-carbon cage containing phosphorus, when combined with platinum, not only improves its specific activity but also exhibits better electrochemical stability in fuel cells.

[0016] A third aspect of the present invention provides a platinum-carbon catalyst comprising a support and platinum supported on the support, wherein the support contains a graphitized carbon nanocage containing phosphorus as described in the first aspect or a graphitized carbon nanocage containing phosphorus prepared by the method described in the second aspect.

[0017] A fourth aspect of this invention provides a method for preparing a platinum-carbon catalyst, the method comprising:

[0018] A platinum-carbon catalyst is obtained by mixing a support with a platinum source in the presence of a solvent and then reducing the mixture in a liquid phase or a gas phase. The support contains either the graphitized carbon nanocage containing phosphorus as described in the first aspect or the graphitized carbon nanocage containing phosphorus prepared by the method described in the second aspect.

[0019] The fifth aspect of the present invention provides the application of the platinum-carbon catalyst described in the third aspect or the platinum-carbon catalyst prepared by the method described in the fourth aspect in fuel cells.

[0020] Using the graphitized carbon nanocages containing phosphorus provided by this invention to make platinum-carbon catalysts is beneficial to improving their oxygen reduction reaction (ORR) activity and stability as fuel cell catalysts (Pt / C catalysts). Attached Figure Description

[0021] Figure 1 This is a TEM image of the phosphorus-doped carbon nanocages prepared in Example 1.

[0022] Figure 2 This is an XPS N1s image of the phosphorus-doped carbon nanocage prepared in Example 1;

[0023] Figure 3 XPS P2p plot of the phosphorus-doped carbon nanocage prepared in Example 1;

[0024] Figure 4 This is the BJH pore size distribution curve of the phosphorus-doped carbon nanocage prepared in Example 1.

[0025] Figure 5 This is a TEM image of the platinum-carbon catalyst prepared in Example 1. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these 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 considered as specifically disclosed herein.

[0027] In this invention, the hollow cage shape has the conventional interpretation in the art, specifically referring to a hollow sphere or quasi-sphere formed by a graphitized carbon layer surrounding it.

[0028] In this invention, the term "mesopore" is defined as a pore with a diameter in the range of 2-50 nm.

[0029] In this invention, the term "graphitized carbon nanocage containing phosphorus" can also be called "phosphorus-doped graphitized carbon nanocage". Specifically, the term refers to phosphorus in various forms that are formed in the graphitized carbon nanocage during the preparation process of the graphitized carbon nanocage.

[0030] According to one specific embodiment of the present invention, the molar percentage of phosphorus atoms measured by XPS is 0.5-10%, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10%.

[0031] According to a specific embodiment of the present invention, the graphitized carbon nanocage containing phosphorus has a hollow cage-like structure with a diameter of 2-100 nm, preferably with a diameter of 2-50 nm, and more preferably with a diameter of 5-30 nm.

[0032] In this invention, the surface morphology of the material is characterized by high-resolution transmission electron microscopy (HRTEM). The HRTEM used is a JEM-2100 (Japan Electronics Corporation), and the HRTEM testing conditions are: accelerating voltage of 200 kV. The diameter of the nano-carbon cage can be measured from the HRTEM images.

[0033] In this invention, X-ray photoelectron spectroscopy analysis was performed on an ESCALab250 X-ray photoelectron spectrometer from Thermo Scientific equipped with ThermoAvantage V5.926 software. The excitation source was monochromatic AlKα X-rays with an energy of 1486.6 eV and a power of 150 W. The transmission energy used for narrow scanning was 30 eV, and the baseline vacuum during analysis was 6.53 × 10⁻⁶. -9 mbar, electron binding energy was corrected using the C1s peak (284.6 eV) of elemental carbon, data processing was performed on Thermo Avantage software, and quantitative analysis was performed using the sensitivity factor method in the analysis module.

[0034] According to the present invention, preferably, in the Raman curve of the graphitized carbon nanocage containing phosphorus, I D / I G The value is less than 1.2, preferably less than 1.1, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or 1.1. The graphitized carbon nanocage containing phosphorus provided by the present invention has obvious D peaks and G peaks, and has a certain degree of graphitization.

[0035] In this invention, the degree of graphitization of graphitized carbon nanocages is characterized by Raman spectroscopy at 1355 cm⁻¹. -1 The peak (D peak) is attributed to structural defects, consisting of amorphous carbon, at 1585 cm⁻¹. -1 The peak (G peak) is attributed to carbon in a planar structure. I0 is typically used. D / I G The degree of graphitization of a material is characterized by the intensity ratio of the D peak to the G peak. D / I G The higher the value, the more defects and the lower the degree of graphitization. The Raman spectrum of the material was obtained using an RM2000 microconfocal Raman spectrometer (Reinshaw product). Technical specifications: The excitation source was a He-Ne laser with a wavelength of 525 nm.

[0036] Preferably, the thickness of the phosphorus-containing graphitized carbon nanocage is 1-10 layers of graphitized carbon atoms, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The thickness of the phosphorus-containing graphitized carbon nanocage is observed by high-resolution transmission electron microscopy (HRTEM).

[0037] Preferably, the graphitized carbon nanocage containing phosphorus has two or more mesoporous distribution peaks; more preferably, the first most probable pore size of the graphitized carbon nanocage containing phosphorus is 2-5 nanometers, for example, 2, 3, 4 or 5 nanometers, and the corresponding second most probable pore size is 10-30 nanometers, for example, 10, 15, 20, 25 or 30 nanometers.

[0038] In this invention, the pore structure properties of the sample were determined by a Quantachrome AS-6B analyzer, and the mesopore distribution curve was calculated from the desorption curve using the Barrett-Joyner-Halenda (BJH) method.

[0039] Preferably, the graphitized carbon nanocage containing phosphorus, as determined by X-ray photoelectron spectroscopy, has a carbon molar percentage of 50-95%, a phosphorus molar percentage of 0.5-10%, and an oxygen molar percentage of 3-40%. Specifically, the carbon molar percentage can be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95%; the phosphorus molar percentage can be, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10%; and the oxygen molar percentage can be, for example, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30%, 35%, or 40%.

[0040] The oxygen element in the graphitized carbon nanocage containing phosphorus can be oxygen element that exists in various forms formed in the graphitized carbon nanocage.

[0041] According to a preferred embodiment of the present invention, the graphitized carbon nanocage containing phosphorus also contains nitrogen, and the molar percentage of nitrogen atoms measured by XPS is 0.5-10%, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10%.

[0042] When the graphitized carbon nanocage containing phosphorus also contains nitrogen, the graphitized carbon nanocage can also be called a phosphorus-nitrogen-doped graphitized carbon nanocage.

[0043] According to a preferred embodiment of the present invention, the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus, as measured by X-ray photoelectron spectroscopy, is 50-95%, the molar percentage of phosphorus is 0.5-10%, the molar percentage of oxygen is 3-40%, and the molar percentage of nitrogen is 0.5-8%. More preferably, the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus, as measured by X-ray photoelectron spectroscopy, is 55-88%, the molar percentage of phosphorus is 1-9%, the molar percentage of oxygen is 10-35%, and the molar percentage of nitrogen is 0.5-3%.

[0044] According to a preferred embodiment of the present invention, the phosphorus-containing graphitized carbon nanocage is composed of carbon, oxygen, phosphorus, and nitrogen. X-ray photoelectron spectroscopy (XPS) shows that the molar percentage of carbon on the surface of the phosphorus-containing graphitized carbon nanocage is 50-95%, the molar percentage of phosphorus is 0.5-10%, the molar percentage of oxygen is 3-40%, and the molar percentage of nitrogen is 0.5-8%. More preferably, XPS shows that the molar percentage of carbon on the surface of the phosphorus-containing graphitized carbon nanocage is 55-88%, the molar percentage of phosphorus is 1-9%, the molar percentage of oxygen is 10-35%, and the molar percentage of nitrogen is 0.5-3%. This preferred embodiment is more conducive to further improving the oxygen reduction reaction (ORR) activity and stability of the catalyst prepared from the phosphorus-containing graphitized carbon nanocage.

[0045] A second aspect of this invention provides a method for preparing graphitized carbon nanocages containing phosphorus, the method comprising the following steps:

[0046] (1) Provide a solution containing a transition metal salt, a carbon source and a solvent, and then dry it to obtain a precursor;

[0047] (2) Under an inert or reducing atmosphere, the precursor obtained in step (1) is subjected to high-temperature pyrolysis at a temperature of 850-1300℃ to obtain pyrolysis products.

[0048] (3) The pyrolysis product is acid washed, then solid-liquid separation and drying are performed to obtain nano-carbon cages;

[0049] (4) The nano carbon cage is mixed with a phosphorus source and then subjected to high-temperature treatment at 300-1500℃.

[0050] The method for preparing graphitized carbon nanocages containing phosphorus provided by this invention involves doping with phosphorus in the final step to obtain graphitized carbon nanocages with a specific phosphorus content. When used in platinum-carbon catalysts, this method is beneficial for improving the performance of platinum-carbon catalysts.

[0051] According to the present invention, preferably, the carbon source is a nitrogen-free organic polybasic acid. Particularly preferably, the nitrogen-free organic polybasic acid is at least one selected from citric acid, maleic acid, pyromellitic acid, terephthalic acid, and malic acid, and more preferably citric acid.

[0052] Preferably, the transition metal salt is selected from at least one of organic acid salts, carbonates, and basic carbonates of transition metals; more preferably, the organic acid salt of the transition metal is an organic carboxylate salt of the transition metal that does not contain heteroatoms, preferably an acetate.

[0053] Preferably, the transition metal is at least one selected from iron, cobalt, nickel, and copper, and more preferably nickel.

[0054] According to some embodiments of the present invention, preferably, the transition metal salt is selected from basic nickel carbonate and / or nickel acetate.

[0055] According to a preferred embodiment of the present invention, in step (1), there is no particular limitation on the method of forming the solution. For example, the solution can be formed by heating, and more preferably by heating and stirring. The present invention also does not particularly limit the heating temperature and the stirring rate, as long as the solution can be formed.

[0056] According to a preferred embodiment of the present invention, preferably, in step (1), the precursor is obtained by dissolving a transition metal salt and a carbon source in a solvent to form a homogeneous solution, and then removing the solvent from the homogeneous solution (drying).

[0057] According to a preferred embodiment of the present invention, the molar ratio of the transition metal salt to the carbon source, calculated as transition metal element, is 1:0.1-10, preferably 1:0.5-5, and more preferably 1:0.5-1. This preferred embodiment is more advantageous in improving the activity of the prepared nano-carbon cages when used as platinum-carbon catalysts.

[0058] The present invention does not particularly limit the type of solvent, as long as it can form a homogeneous solution. Preferably, the solvent is water and / or ethanol, more preferably water. The present invention also does not particularly limit the amount of solvent used, as long as it can form a homogeneous solution.

[0059] According to the method provided by the present invention, the temperature of the high-temperature pyrolysis is preferably 900-1200℃.

[0060] Preferably, in step (2), the high-temperature pyrolysis process includes: heating to the high-temperature pyrolysis temperature at a rate of 0.5-30℃ / min, preferably 1-20℃ / min, and even more preferably 5-10℃ / min, and then maintaining a constant temperature. A wide range of constant temperature time is available, taking into account both effectiveness and energy saving; the preferred constant temperature time is 20-600 min, more preferably 60-480 min.

[0061] According to a preferred embodiment of the present invention, in step (2), the temperature is raised to the high-temperature pyrolysis temperature in two stages, specifically: first, the temperature is raised to 400-800℃, preferably 500-700℃, at a rate of 1-20℃ / min, preferably 5-10℃ / min, and held at that temperature for 20-600min, preferably 60-480min; then, the temperature is raised to the high-temperature pyrolysis temperature at a rate of 1-20℃ / min, preferably 5-10℃ / min, and held at that temperature for 20-600min, preferably 60-480min.

[0062] According to some embodiments of the present invention, preferably, in step (2), the inert atmosphere is provided by at least one of nitrogen, argon, neon, and helium; and / or,

[0063] The reducing atmosphere is provided by hydrogen and optionally an inert gas, which is at least one of nitrogen, argon, neon, and helium. There is no particular limitation on the hydrogen content in the reducing atmosphere, which can be 1-100% by volume.

[0064] According to some embodiments of the present invention, in step (3), the pyrolysis product is acid-washed using an acid pickling agent. Specifically, the pyrolysis product is mixed with the acid pickling agent. The present invention does not have a particular limitation on the mixing method; it can be mixed by ultrasound or stirring. The acid pickling agent can be an acid conventionally used in the art, as long as it can remove the transition metals in the pyrolysis product. Preferably, the acid pickling agent is an aqueous solution of inorganic acid and / or an aqueous solution of organic acid, preferably at least one of aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, and citric acid, more preferably an aqueous solution of hydrochloric acid. Preferably, the concentration of the aqueous solution of inorganic acid and / or the aqueous solution of organic acid is 0.1-10 mol / L; the pH value of the acid pickling agent is less than 7. The present invention does not have a particular requirement for the amount of the acid pickling agent used, as long as it can remove the transition metals in the pyrolysis product.

[0065] According to some embodiments of the present invention, preferably, in step (3), the pickling temperature is 20-120°C, more preferably 60-100°C; and the time is 0.1-48h, more preferably 4-12h.

[0066] According to some embodiments of the present invention, in step (3), there is no particular limitation on the method of solid-liquid separation, and solid-liquid separation methods known in the art can be used, such as filtration.

[0067] Step (3) of the present invention preferably includes washing the solid product obtained from solid-liquid separation before the drying. The washing is used to remove acid and metal ions remaining on the nano-carbon cages during the acid washing process. Therefore, various water washing methods that can wash the nano-carbon cages to neutrality are applicable to the present invention.

[0068] According to some embodiments of the present invention, the drying is used to remove water from the carbon nanocages. The drying can be performed under normal pressure or reduced pressure. Drying conditions may include a temperature of 80-140°C and a time of 6-10 hours.

[0069] According to the method provided by the present invention, there is no particular limitation on the mixing method of the nano-carbon cage and the phosphorus source in step (4). As long as the mixing is uniform, it can be carried out in the presence of a solvent and then dried, or it can be done by dry mixing and then grinding. There is no particular limitation on the specific mixing parameters, and those skilled in the art can make adaptive selections according to specific circumstances.

[0070] According to the method provided by the present invention, in step (4), the high temperature treatment temperature is preferably 400-1200℃, for example 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃, and any value in any range formed by any two of these values. More preferably, the high temperature treatment temperature is 450-1100℃.

[0071] Preferably, the high-temperature treatment time is 30-300 min, for example, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, and any value within the range formed by any two of these values.

[0072] The present invention offers a wide range of selectable heating rates for the high-temperature treatment, allowing those skilled in the art to make adaptive selections based on specific circumstances. This embodiment uses 5°C / min as an example for illustrative purposes, but the invention is not limited thereto.

[0073] The present invention allows for a wide range of phosphorus source selection, as long as it can provide phosphorus in the nano-carbon cage. Preferably, the phosphorus source is selected from at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate. More preferably, the phosphorus source also contains nitrogen, and more preferably, the phosphorus source is ammonium dihydrogen phosphate and / or diammonium hydrogen phosphate.

[0074] Preferably, the amount of the nano-carbon cage and the phosphorus source is such that the obtained graphitized nano-carbon cage containing phosphorus has a phosphorus atom molar percentage content of 0.5-10% and a nitrogen atom percentage content of 0-10%, as measured by XPS, preferably 0.5-10%.

[0075] Preferably, the amounts of the carbon source, transition metal salt, and phosphorus source are such that, as measured by X-ray photoelectron spectroscopy, the molar percentage of carbon in the prepared graphitized carbon nanocage is 50-95%, the molar percentage of phosphorus is 0.5-10%, and the molar percentage of oxygen is 3-40%. More preferably, as measured by X-ray photoelectron spectroscopy, the molar percentage of carbon on the surface of the phosphorus-containing graphitized carbon nanocage is 50-95%, the molar percentage of phosphorus is 0.5-10%, the molar percentage of oxygen is 3-40%, and the molar percentage of nitrogen is 0.5-8%. Even more preferably, as measured by X-ray photoelectron spectroscopy, the molar percentage of carbon on the surface of the phosphorus-containing graphitized carbon nanocage is 55-88%, the molar percentage of phosphorus is 1-9%, the molar percentage of oxygen is 10-35%, and the molar percentage of nitrogen is 0.5-3%.

[0076] A third aspect of the present invention provides a platinum-carbon catalyst comprising a support and platinum supported on the support, wherein the support contains graphitized carbon nanocages containing phosphorus as described in the first aspect or graphitized carbon nanocages containing phosphorus prepared by the method described in the second aspect.

[0077] Preferably, based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum is 0.1-70%, more preferably 0.5-70%, for example 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70%, and any value within any range formed by any two of these values.

[0078] A fourth aspect of this invention provides a method for preparing a platinum-carbon catalyst, the method comprising:

[0079] A platinum-carbon catalyst is obtained by mixing a support with a platinum source in the presence of a solvent and then reducing the mixture in a liquid phase or a gas phase. The support contains either the graphitized carbon nanocage containing phosphorus as described in the first aspect or the graphitized carbon nanocage containing phosphorus prepared by the method described in the second aspect.

[0080] Preferably, the amount of support and platinum source is such that, based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum in the prepared catalyst is 0.1-70%, preferably 0.5-70%, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70%, and any value within any range of any two of these values. More preferably, based on the total amount of the carbon-based catalyst, the mass percentage of platinum is 30-50%.

[0081] According to a preferred embodiment of the present invention, a platinum-carbon catalyst is obtained by liquid-phase reduction after mixing a support and a platinum source in the presence of a solvent.

[0082] The support and platinum source are mixed in the presence of a solvent, and the pH is adjusted preferably to 8-12 (e.g., 8, 9, 10, 11 or 12). A reducing agent is added for reduction, and then the mixture is dried (preferably washed before drying) to obtain a platinum-carbon catalyst.

[0083] In this preferred embodiment, preferably, the platinum source is at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, and other inorganic platinum salts.

[0084] Preferably, the platinum source is provided in the form of a solution, and its concentration is preferably 0.5 mol / L to 5 mol / L, for example 0.5, 1, 2, 3, 4 or 5 mol / L, and any value within any two of these values.

[0085] The present invention allows for a wide range of solvent selection; preferably, the solvent is water.

[0086] The pH is preferably adjusted using an alkaline solution, which may be a solution of one or more alkaline substances selected from sodium carbonate, potassium carbonate, ammonia, potassium hydroxide, and sodium hydroxide (preferably an aqueous solution).

[0087] In this preferred embodiment, the reducing agent is preferably selected from one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride, and glycerol.

[0088] In this preferred embodiment, the molar ratio of the reducing agent to the platinum source (calculated as Pt) is preferably between 2 and 100, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, and any value within the range formed by any two of these values.

[0089] In this preferred embodiment, the reduction temperature is preferably 50-150℃, for example 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150℃, and any value within any range formed by any two of these values. The reduction time is preferably 2-15h, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15h, and any value within any range formed by any two of these values.

[0090] In another preferred embodiment, the process of obtaining a platinum-carbon catalyst by gas-phase reduction after mixing the support and platinum source in the presence of a solvent includes: mixing the support and platinum source in the presence of a solvent, removing the solvent to obtain a precursor material; and heat-treating the precursor material in a reducing atmosphere.

[0091] In this preferred embodiment, the heat treatment is preferably performed at 80-300°C (for example, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300°C, and any value within the range formed by any two of these values) for 1-4 hours.

[0092] In this preferred embodiment, the platinum source is selected from at least one of chloroplatinic acid, chloroplatinate, tetraammineplatinum acetate, and platinum acetylacetonate.

[0093] The present invention has a wide range of solvents that can be selected. Preferably, the solvent is one or more of water, alcohol solvents and ketone solvents, and more preferably, the solvent is water and / or ethanol.

[0094] In this preferred embodiment, the mixture is further further comprising: allowing the mixed material to stand before removing the solvent, preferably for 10 hours or more, more preferably 15-48 hours. This method is more conducive to the loading of platinum and the full dispersion of Pt on the carrier surface.

[0095] In this preferred embodiment, the drying temperature during solvent removal is below 100°C.

[0096] In this preferred embodiment, the reducing atmosphere can be provided by hydrogen and optionally an inert gas (the selection range can be the same as the selection range described above), more preferably by a mixed atmosphere of hydrogen and nitrogen; preferably, the hydrogen content in the mixed atmosphere is 5-50% by volume.

[0097] The fifth aspect of this invention provides the application of the platinum-carbon catalyst described in the third aspect or the platinum-carbon catalyst prepared by the method described in the fourth aspect in fuel cells. The platinum-carbon catalyst provided by this invention is beneficial for improving the oxygen reduction reaction (ORR) activity and stability of fuel cell catalysts. Since this invention mainly relates to the improvement of catalysts, there are no particular limitations on other operating conditions and structures of fuel cells when the platinum-carbon catalyst of this invention is applied in fuel cells; those skilled in the art can make appropriate selections according to specific operating conditions.

[0098] According to the application of the present invention, the fuel cell is preferably a proton exchange membrane hydrogen fuel cell.

[0099] According to the application of the present invention, the platinum-containing carbon-based catalyst is preferably a platinum-carbon catalyst for the anode or cathode of a proton exchange membrane hydrogen fuel cell.

[0100] The present invention will be described in detail below through embodiments.

[0101] Unless otherwise specified, all reagents used in this invention are of analytical grade and are commercially available.

[0102] The specific instruments and parameters for characterization using high-resolution transmission electron microscopy (HRTEM), BET testing, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy are as described above and will not be repeated here.

[0103] ORR electrochemical performance testing was conducted using Solartron Analytical EnergyLab and Princeton Applied Research (Model 636A) instruments. The methods and test conditions were as follows: The catalyst polarization curve (LSV) was measured at 1600 rpm in O2-saturated 0.1 M HClO4, and the electrochemical active area (ECSA) was measured in Ar-saturated 0.1 M HClO4. For stability testing, after 5000 cycles in O2-saturated 0.1 M HClO4 within the range of 0.6 V–0.95 V (vs. RHE), LSV and ECSA were measured using the same method. During these tests, the catalyst was prepared as a uniformly dispersed slurry and coated onto a 5 mm diameter glassy carbon electrode. The platinum content of the catalyst on the electrode was controlled within the range of 1–4 μg. No iR correction was performed in the calculations.

[0104] Preparation Example 1

[0105] This preparation example illustrates the preparation of carbon nanocages.

[0106] (1) Weigh 15g of basic nickel carbonate and 15g of citric acid, add them to a beaker containing 40mL of deionized water, stir and mix them evenly at 80℃, and continue to heat and evaporate to dryness to obtain a solid precursor.

[0107] (2) Place the precursor obtained in step (1) into a ceramic boat, then place the ceramic boat in the constant temperature zone of a tube furnace, introduce nitrogen gas with a flow rate of 80 mL / min, and heat it to 600℃ at a rate of 10℃ / min. After holding the temperature for 1 hour, continue to heat it to 900℃ at a rate of 10℃ / min and hold the temperature for 2 hours. Stop heating and cool it to room temperature under a nitrogen atmosphere to obtain the pyrolysis product.

[0108] (3) Add the pyrolysis product obtained in step (2) to an aqueous solution containing 2M hydrochloric acid and stir at 90°C for 8 hours. Then filter, collect the filtrate, wash with deionized water until the filtrate is neutral, and then dry the filter cake in a constant temperature oven at 120°C for 6 hours to obtain nano carbon cages.

[0109] TEM characterization of the carbon nanocages revealed that the prepared material is a hollow cage-like carbon nanomaterial with a size of 5-30 nm. XPS characterization showed that, in addition to carbon, oxygen was also present on the surface of the material.

[0110] The following examples illustrate phosphorus-doped nano-carbon cages and platinum-carbon catalysts and their preparation.

[0111] Example 1

[0112] Preparation of phosphorus-doped carbon nanocages

[0113] Take 0.1 g of the nano-carbon cage prepared in Preparation Example 1, add 0.074 g of ammonium dihydrogen phosphate, grind for 5 minutes, and calcine in an atmosphere furnace at 1100 °C for 2 hours. The heating rate is 5 °C / min to obtain phosphorus-doped nano-carbon cages. Figure 1 The image shows a TEM image of the phosphorus-doped carbon nanocages, which have a hollow cage-like structure with a diameter of 10-20 nm. Figure 2 The image shows the XPS N1s plot of the prepared phosphorus-doped nano-carbon cages. Figure 3 XPS P2p plot of the prepared phosphorus-doped carbon nanocages. Figure 4 The image shows the pore size distribution curve of the phosphorus-doped carbon nanocage BJH. The material exhibits two mesopore distribution peaks at 3.63 nm and 16.90 nm, as measured by Raman spectroscopy. D / I G It is 1.179.

[0114] The thickness of the graphitized carbon nanocage containing phosphorus is 5-10 layers of graphitized carbon atoms.

[0115] Preparation of platinum-carbon catalysts

[0116] 0.06 g of phosphorus-doped carbon nanocage material was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added with stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The resulting mixture was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst. Figure 5 The image shows a TEM image of the prepared platinum-carbon catalyst.

[0117] The contents of each element in the phosphorus-doped nano-carbon cage and the contents of platinum in the catalyst are listed in Table 1.

[0118] Example 2

[0119] Preparation of phosphorus-doped carbon nanocages

[0120] Take 0.1 g of the nano-carbon cage prepared in Preparation Example 1, add 0.074 g of ammonium dihydrogen phosphate, grind for 5 minutes, and calcine in an atmosphere furnace at 650 °C for 2 hours. The heating rate is 5 °C / min to obtain phosphorus-doped nano-carbon cages.

[0121] Preparation of platinum-carbon catalysts

[0122] 0.06 g of phosphorus-doped carbon nanocage material was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst.

[0123] The contents of each element in the phosphorus-doped nano-carbon cage and the contents of platinum in the catalyst are listed in Table 1.

[0124] Example 3

[0125] Preparation of phosphorus-doped carbon nanocages

[0126] Take 0.1 g of the nano-carbon cage prepared in Preparation Example 1, add 0.19 g of ammonium dihydrogen phosphate, grind for 5 minutes, and calcine in an atmosphere furnace at 650 °C for 2 hours. The heating rate is 5 °C / min to obtain phosphorus-doped nano-carbon cages.

[0127] Preparation of platinum-carbon catalysts

[0128] 0.06 g of phosphorus-doped carbon nanocage material was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst.

[0129] The contents of each element in the phosphorus-doped nano-carbon cage and the contents of platinum in the catalyst are listed in Table 1.

[0130] Example 4

[0131] Preparation of phosphorus-doped carbon nanocages

[0132] Take 0.1 g of the nano-carbon cage prepared in Preparation Example 1, add 0.19 g of ammonium dihydrogen phosphate, grind for 5 minutes, and calcine in an atmosphere furnace at 450 °C for 2 hours. The heating rate is 5 °C / min to obtain phosphorus-doped nano-carbon cages.

[0133] Preparation of platinum-carbon catalysts

[0134] 0.06 g of phosphorus-doped carbon nanocage material was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst.

[0135] The contents of each element in the phosphorus-doped nano-carbon cage and the contents of platinum in the catalyst are listed in Table 1.

[0136] Example 5

[0137] Preparation of phosphorus-doped carbon nanocages

[0138] Take 0.1 g of the nano-carbon cage prepared in Preparation Example 1, add 0.19 g of ammonium dihydrogen phosphate, grind for 5 minutes, and calcine in an atmosphere furnace at 1100℃ for 2 hours. The heating rate is 5℃ / min to obtain phosphorus-doped nano-carbon cages.

[0139] Preparation of platinum-carbon catalysts

[0140] 0.06 g of phosphorus-doped carbon nanocage material was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst.

[0141] The contents of each element in the phosphorus-doped nano-carbon cage and the contents of platinum in the catalyst are listed in Table 1.

[0142] Example 6 (Gas-supported Platinum)

[0143] The preparation of phosphorus-doped carbon nanocages is the same as in Example 1.

[0144] Preparation of platinum-carbon catalysts

[0145] 0.05 g of phosphorus-doped carbon nanocages were added to 7.01 mL of chloroplatinic acid aqueous solution (1 g chloroplatinic acid / 100 mL aqueous solution), sonicated for 0.5 h, allowed to stand for 48 h, and dried in a 60 °C oven for 12 h. The sample was then placed in a tube furnace and heated to 160 °C under a mixed atmosphere of nitrogen and hydrogen (hydrogen volume content 40%), and allowed to cool naturally for 1.5 h to obtain a phosphorus-doped carbon nanocage-supported platinum catalyst. The platinum content in the catalyst is listed in Table 1.

[0146] Comparative Example 1

[0147] 0.06 g of the nano-carbon cage material prepared in Example 1 was dispersed in 20 mL of deionized water, and a certain amount of chloroplatinic acid was added. The mixture was ultrasonically dispersed to form a suspension, and sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80 °C, and formic acid was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 8 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the platinum-carbon catalyst.

[0148] Table 1

[0149]

[0150]

[0151] The ORR performance of the platinum-carbon catalysts prepared in the above examples is shown in Table 2 below.

[0152] Table 2

[0153]

[0154] As can be seen from the above data, the graphitized carbon nanocage containing phosphorus provided by the present invention has good catalytic performance when used as a support in fuel cell catalysts (Pt / C catalysts), and greatly improves cycle performance while maintaining a high mass-to-specific activity.

[0155] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A platinum-carbon catalyst for proton exchange membrane hydrogen fuel cells, characterized in that, The catalyst comprises a support and platinum supported on the support, the support comprising graphitized carbon nanocages containing phosphorus, the graphitized carbon nanocages containing phosphorus having a hollow cage-like structure with a diameter of 2-100 nm, and the molar percentage of phosphorus atoms measured by XPS being 0.5-10%. The graphitized carbon nanocage has two or more mesoporous distribution peaks.

2. The platinum-carbon catalyst according to claim 1, wherein, The graphitized carbon nanocage containing phosphorus has a hollow cage-like structure with a diameter of 2-50 nm.

3. The platinum-carbon catalyst according to claim 2, wherein, The graphitized carbon nanocage containing phosphorus has a hollow cage-like structure with a diameter of 5-30 nm.

4. The platinum-carbon catalyst according to claim 1, wherein, In the Raman curve of the graphitized carbon nanocage, I D / I G The value is less than 1.

2.

5. The platinum-carbon catalyst according to claim 1, wherein, The thickness of the graphitized carbon nanocage containing phosphorus is 1-10 layers of graphitized carbon atoms.

6. The platinum-carbon catalyst according to claim 1 or 2, wherein, The graphitized carbon nanocage has a first most probable pore size of 2-5 nanometers and a second most probable pore size of 10-30 nanometers.

7. The platinum-carbon catalyst according to claim 1, wherein, The graphitized carbon nanocage containing phosphorus contains carbon, oxygen, and phosphorus. X-ray photoelectron spectroscopy shows that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus is 50-95%, the molar percentage of phosphorus is 0.5-10%, and the molar percentage of oxygen is 3-40%.

8. The platinum-carbon catalyst according to claim 1, wherein, The graphitized carbon nanocage also contains nitrogen, with a nitrogen atom molar percentage of 0.5-10% as measured by XPS.

9. The platinum-carbon catalyst according to claim 8, wherein, X-ray photoelectron spectroscopy revealed that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus was 50-95%, the molar percentage of phosphorus was 0.5-10%, the molar percentage of oxygen was 3-40%, and the molar percentage of nitrogen was 0.5-8%.

10. The platinum-carbon catalyst according to claim 9, wherein, X-ray photoelectron spectroscopy revealed that the molar percentage of carbon on the surface of the graphitized carbon nanocage containing phosphorus was 55-88%, the molar percentage of phosphorus was 1-9%, the molar percentage of oxygen was 10-35%, and the molar percentage of nitrogen was 0.5-3%.

11. The platinum-carbon catalyst according to claim 1, wherein, The method for preparing the phosphorus-containing graphitized carbon nanocage includes the following steps: (1) Provide a solution containing a transition metal salt, a carbon source and a solvent, and then dry it to obtain a precursor; (2) Under an inert or reducing atmosphere, the precursor obtained in step (1) is subjected to high-temperature pyrolysis at a temperature of 850-1300℃ to obtain pyrolysis products. (3) The pyrolysis product is acid washed, and then solid-liquid separation and drying are performed to obtain nano-carbon cages; (4) The nano carbon cage is mixed with a phosphorus source and then subjected to high temperature treatment at 300-1500℃.

12. The platinum-carbon catalyst according to claim 11, wherein, In step (1), The carbon source is a nitrogen-free organic polybasic acid.

13. The platinum-carbon catalyst according to claim 12, wherein, The carbon source is at least one of citric acid, maleic acid, pyromellitic acid, terephthalic acid, and malic acid.

14. The platinum-carbon catalyst according to claim 13, wherein, The carbon source is citric acid.

15. The platinum-carbon catalyst according to claim 11, wherein, The transition metal salt is selected from one or more of the organic acid salts, carbonates, and basic carbonates of transition metals.

16. The platinum-carbon catalyst according to claim 15, wherein, The organic acid salt of the transition metal is an organic carboxylic acid salt of the transition metal that does not contain heteroatoms.

17. The platinum-carbon catalyst according to claim 16, wherein, The organic acid salt of the transition metal is an acetate.

18. The platinum-carbon catalyst according to claim 11, wherein, The transition metal is at least one of iron, cobalt, nickel, and copper.

19. The platinum-carbon catalyst according to claim 18, wherein, The transition metal is nickel.

20. The platinum-carbon catalyst according to claim 11, wherein, The molar ratio of the transition metal salt to the carbon source, calculated as a transition metal element, is 1:0.1-10.

21. The platinum-carbon catalyst according to claim 20, wherein, The molar ratio of the transition metal salt to the carbon source, calculated as a transition metal element, is 1:0.5-5.

22. The platinum-carbon catalyst according to claim 11, wherein, The solvent is water.

23. The platinum-carbon catalyst according to claim 11, wherein, In step (2), The high-temperature pyrolysis process includes: heating to the high-temperature pyrolysis temperature at a rate of 0.5-30℃ / min, and then maintaining a constant temperature; And / or, the isothermal time is 20-600 min; And / or, the temperature of the high-temperature pyrolysis is 900-1200℃; And / or, the inert atmosphere is provided by at least one of nitrogen, argon, neon and helium, and the reducing atmosphere is provided by hydrogen and optionally an inert gas.

24. The platinum-carbon catalyst according to claim 23, wherein, In step (2), The high-temperature pyrolysis process includes: heating to the high-temperature pyrolysis temperature at a rate of 1-20℃ / min, and then maintaining a constant temperature; And / or, the isothermal time is 60-480 min.

25. The platinum-carbon catalyst according to claim 24, wherein, In step (2), The high-temperature pyrolysis process includes: heating to the high-temperature pyrolysis temperature at a rate of 5-10℃ / min, and then maintaining a constant temperature.

26. The platinum-carbon catalyst according to claim 11, wherein, In step (3), The pickling agent used to pickle the pyrolysis products is an aqueous solution of inorganic acid and / or an aqueous solution of organic acid; And / or, the pH value of the inorganic acid aqueous solution or the organic acid aqueous solution is less than 7; And / or, the pickling temperature is 20-120℃; the time is 0.1-48h.

27. The platinum-carbon catalyst according to claim 26, wherein, In step (3), The pickling agent used to acid wash the pyrolysis products is at least one of hydrochloric acid aqueous solution, sulfuric acid aqueous solution, nitric acid aqueous solution and citric acid aqueous solution; And / or, the pickling temperature is 60-100℃; the time is 4-12h.

28. The platinum-carbon catalyst according to claim 27, wherein, In step (3), The acid washing agent used to acid wash the pyrolysis products is an aqueous solution of hydrochloric acid.

29. The platinum-carbon catalyst according to claim 11, wherein, In step (4), The high-temperature treatment temperature is 400-1200℃; And / or, the high-temperature treatment time is 30-300 min; And / or, the phosphorus source is selected from at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; And / or, the amount of the nano-carbon cage and the phosphorus source is such that the obtained graphitized nano-carbon cage containing phosphorus has a phosphorus atom molar percentage content of 0.5-10% and a nitrogen atom percentage content of 0-10% as measured by XPS.

30. The platinum-carbon catalyst according to claim 29, wherein, In step (4), The phosphorus source contains nitrogen. And / or, the amount of the nano-carbon cage and the phosphorus source is such that the percentage of nitrogen atoms in the graphitized nano-carbon cage containing phosphorus is 0.5-10% as measured by XPS.

31. The platinum-carbon catalyst according to claim 30, wherein, In step (4), The phosphorus source is ammonium dihydrogen phosphate and / or diammonium hydrogen phosphate.

32. The platinum-carbon catalyst according to claim 30, wherein, Based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum is 0.1-70%.

33. The platinum-carbon catalyst according to claim 32, wherein, Based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum is 0.5-70%.

34. A method for preparing a platinum-carbon catalyst for a proton exchange membrane hydrogen fuel cell according to any one of claims 1-33, the method comprising: Platinum-carbon catalysts are obtained by mixing the support and platinum source in the presence of a solvent and then reducing them by liquid phase or gas phase. The carrier contains graphitized carbon nanocages containing phosphorus.

35. The preparation method according to claim 34, wherein, The amount of support and platinum source used is such that, based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum in the prepared catalyst is 0.1-70%.

36. The preparation method according to claim 35, wherein, The amount of support and platinum source used is such that, based on the total amount of the platinum-carbon catalyst, the mass percentage of platinum in the prepared catalyst is 0.5-70%.

37. The preparation method according to claim 34, wherein, Platinum-carbon catalysts are obtained by mixing a support and a platinum source in the presence of a solvent and then reducing them in the liquid phase, including: The support and platinum source were mixed in the presence of a solvent, the pH was adjusted, a reducing agent was added for reduction, and then dried to obtain a platinum-carbon catalyst.

38. The preparation method according to claim 37, wherein, Adjust the pH to 8-12.

39. The preparation method according to claim 37, wherein, The platinum source is selected from at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, and other inorganic platinum salts; and / or, the concentration of the platinum source is 0.5-5 mol / L.

40. The preparation method according to claim 37, wherein, The reducing agent is selected from one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride, and glycerol.

41. The preparation method according to claim 37, wherein, The molar ratio of the reducing agent to the platinum source (calculated as Pt) is 2-100.

42. The preparation method according to claim 37, wherein, The reduction temperature is 50-150℃, and the reduction time is 2-15h.

43. The preparation method according to claim 34, wherein, Platinum-carbon catalysts are obtained by mixing a support and a platinum source in the presence of a solvent and then reducing them in the gas phase, including: The carrier and platinum source are mixed in the presence of a solvent, and the solvent is removed to obtain a precursor material. The precursor material is then heat-treated in a reducing atmosphere.

44. The preparation method according to claim 43, wherein, The precursor material is subjected to heat treatment at 80-300℃ for 1-4 hours.

45. The preparation method according to claim 43, wherein, The platinum source is selected from at least one of chloroplatinic acid, chloroplatinate, tetraammineplatinum acetate, and platinum acetylacetonate.

46. ​​The preparation method according to claim 43, wherein, The solvent is one or more of water, alcohol solvents, and ketone solvents.

47. The preparation method according to claim 46, wherein, The solvent is water and / or ethanol.

48. The preparation method according to claim 43, wherein, Before removing the solvent, allow the mixed materials to stand.

49. The preparation method according to claim 48, wherein, The settling time is more than 10 hours.

50. The preparation method according to claim 49, wherein, The settling time is 15-24 hours.

51. The preparation method according to claim 43, wherein, The drying temperature during solvent removal is below 100℃.

52. The preparation method according to claim 43, wherein, The reducing atmosphere is provided by hydrogen and optionally an inert gas.

53. The preparation method according to claim 52, wherein, The reducing atmosphere is provided by a mixture of hydrogen and nitrogen.

54. The preparation method according to claim 53, wherein, The hydrogen content in the mixed atmosphere is 5-30% by volume.

Images