CN1186838C - Preparation method of proton-exchange membrane fuel cell electrode catalyst - Google Patents

Abstract

A method for preparing an electrode catalyst for a proton exchange membrane fuel cell, characterized in that: the preparation process of the catalyst is carried out under the same solvent system, and the solvent is selected from one or more of dihydric alcohols and trihydric alcohols from C2 to C8 , or its aqueous solution, wherein the volume percentage of water is 0 to 95%; in the preparation process of the catalyst, the solvent acts as a reducing agent, a dispersant, and a protective agent; the preparation steps include: solution configuration, mixing, adjustment The pH of the mixed solution is adjusted to alkaline, the temperature is raised to reduce, and the pH is adjusted to acid with hydrochloric acid solution. The method of the present invention does not require pretreatment of metal precursors, and does not require any recognized surfactants or other polymeric organic substances as protective agents to prepare highly dispersed metal-supported catalysts with fine and uniform distribution. The metal content of the prepared supported catalysts is Can be as high as 90%.

Description

A kind of preparation method of proton exchange membrane fuel cell electrode catalyst

Technical field:

The present invention relates to the preparation method of Pt-based supported single-component, dual-component and multi-component catalysts, and the application of the catalyst as an electrode catalyst in a proton exchange membrane fuel cell, which belongs to the production of catalysts by chemical and chemical methods technical field and fuel cell field.

Background technique:

Fuel cells have the advantages of high energy conversion efficiency, no pollution, no noise, etc., and are green energy. The power source of the vehicle has been applied. Using hydrogen as fuel, although the battery performance is excellent, but the fuel source is a big problem. The cost of high-purity hydrogen is relatively high. At the same time, there are huge difficulties in the storage and transportation of hydrogen as a gas fuel. At present, the ideal method is in-situ system Hydrogen or liquid fuels such as gasoline or various alcohols are catalytically decomposed to produce hydrogen, but the hydrogen produced by this method inevitably contains various by-products of decomposition, such as carbon dioxide, carbon monoxide, etc., despite strict purification, the hydrogen still contains a small amount of carbon monoxide and is extremely difficult to remove. However, even a small amount of CO in the fuel will quickly lead to catalyst poisoning and deactivation, which greatly reduces the efficiency and life of the battery. Therefore, the development of high-performance CO-resistant anode catalysts is the key to the promotion and wide application of PEMFCs. Direct Methanol Fuel Cells (DMFCs) can directly use methanol as fuel without an intermediate conversion device. It has the advantages of simple system structure, high volumetric energy density, and convenient fuel replenishment. It is especially suitable for mobile power sources such as mobile phones, notebook computers and Electric vehicle power supply, etc. At present, one of the core problems of DMFCs using proton exchange membrane as electrolyte is that the electrocatalytic oxidation activity of methanol at the anode is not high at low temperature, and the catalytic polarization is severe. It is necessary to overcome the high polarization potential to ensure a certain reaction rate. As far as DMFCs are concerned, the efficiency loss mainly comes from the catalytic polarization, that is, the problem of the electrode catalyst. Fuel cells of this type that use other alcohols as fuels have similar, if not more severe, anode catalyst problems. The above two types of batteries are low-temperature batteries, which have high requirements on the activity of catalysts. At present, the electrode catalysts that can maintain a certain catalytic activity at low temperatures are still dominated by noble metals, especially metal platinum. These precious metals have limited reserves, scarce resources, and high prices It is expensive, and it is necessary to improve the utilization efficiency of noble metals, and the preparation of nanoscale uniformly dispersed supported catalysts is undoubtedly necessary to promote the development of proton exchange membrane fuel cells. On the other hand, the use of cheap metals and these noble metals to form bi-component or multi-component catalysts can also effectively increase the catalytic activity and stability of noble metals, and the addition of other metals can also help improve the utilization of noble metals. However, how to effectively improve the dispersion of noble metals, how to effectively improve the interaction between noble metals and other components, improve the activity and stability of catalysts, and improve the utilization of noble metal resources are the key factors for the preparation of various catalysts including electrode catalysts. urgent problems that need to be resolved urgently.

In response to the above problems and requirements, many researchers have tried various methods to prepare and improve electrode catalysts and other types of noble metal catalysts. As far as the current preparation methods of various platinum-based electrode catalysts can be roughly divided into three categories.

One is the colloid method to prepare electrode catalysts. The method is mainly prepared by preparing a relatively stable metal oxide colloid, then promoting sedimentation or transferring it to a carrier, and then treating it through other processes. Document 1 [HGRetrow, RGAllen USP 3,992,331], document 2 [M.Watanabe, J.Electroanal.Chem.229 (1987) 395] and document 3 [AKShukla, J.Appl.Electrochem., 29 (1999) 129] are mainly Carbon-supported platinum and carbon-supported platinum ruthenium catalysts are prepared by this method. Document 1 first prepares chloroplatinic acid into Na ₆ [Pt(SO ₃ ) ₄ ], then exchanges the sodium ions in Na ₆ [Pt(SO ₃ ) ₄ ] with hydrogen ions by ion exchange, and heats and boils in the air. Release excess sulfite ions, and finally dry at a certain temperature to obtain a black colloid of Pt oxide, which can be dispersed in water or other solvents again, so that it can be easily loaded on various carriers. Using this method, a Pt catalyst of 1.5-2.5 nanometers can be prepared, and at the same time, since the chloride ion is replaced in advance, the method can effectively avoid the loss of catalytic activity caused by a trace amount of chloride ion in the catalyst. The method for preparing the catalyst in Document 2 is to prepare Na ₆ [Pt(SO ₃ ) ₄ ] from chloroplatinic acid first, but it is different from Document 1 in that this method does not separate Na ₆ [Pt(SO ₃ ) ₄ ] , but directly add excess hydrogen peroxide to oxidize and decompose it to form a stable platinum oxide colloid, and then drop ruthenium compounds such as ruthenium trichloride to the colloid to quickly decompose excess hydrogen peroxide, while ruthenium It is also oxidized to form ruthenium oxide combined with platinum oxide to form oxide clusters, which are deposited on activated carbon and other supports through pH adjustment; the platinum in it can be reduced to a metallic state by hydrogen. The catalyst prepared by this method is a metal cluster with ruthenium oxide as the core and platinum on the outer surface. The method for preparing the catalyst in Document 3 is to convert all the chlorides of platinum and ruthenium into sulfurous acid complexes, namely Na ₆ [Pt(SO ₃ ) ₄ ] and Na ₆ [Ru(SO ₃ ) ₄ ], and convert its separated. Then they are mixed and then oxidized and decomposed into mixed oxide colloids with hydrogen peroxide, and then loaded on activated carbon. Or as in document 2, Na ₆ [Pt(SO ₃ ) ₄ ] is first oxidatively decomposed with hydrogen peroxide, and then Na ₆ [Ru(SO ₃ ) ₄ ] is added to decompose excess hydrogen peroxide, while Na ₆ [Ru( SO ₃ ) ₄ ] was transformed into ruthenium oxide, and the two metal oxides were co-precipitated on the activated carbon by adjusting the pH.

The other is to use surfactants or other organic macromolecules as protective agents to prepare highly dispersed nano-noble metal particles, or to load the prepared nano-noble metal particles on the carrier by other means. This type of method can still obtain very high metal dispersion even in the case of high loading of precious metals. However, this type of method has high requirements on solvents, surfactants or protective agents and operating conditions, and at the same time, the operation is complicated and the cost is high. Document 4 [HBnnemann, et al, USP 5,641,723] uses borohydric acid quaternary ammonium salt NR ₄ BR ₃ H with a long carbon chain as a reducing agent and a protective agent to reduce platinum ruthenium and other transition metal precursors to prepare granular Nanoscale metal colloids with narrow diameter distribution. This method requires an anhydrous and oxygen-free system, and the typical preparation process is completed in a tetrahydrofuran system. The performance of the platinum-ruthenium alloy catalyst prepared by the method in the hydrogen-oxygen proton exchange membrane fuel cell against carbon monoxide poisoning is slightly better than that of commercial catalysts.

The typical feature of the third type of preparation method is the impregnation of the noble metal precursor on the surface of the support. The key to this type of method is to deposit PtRu and other precious metal precursors such as chloroplatinic acid, Ru ₃ CO ₁₂ , etc. on the surface of the carrier by impregnation, and then pass liquid phase reducing agents such as hydrazine hydrate, borohydride, etc., or gas phase reducing agents Various catalysts can be prepared by reducing the carrier impregnated with the precursor, such as hydrogen. This type of method can be used to prepare multi-component catalysts, but this type of method requires the carrier to have a high specific surface area, and it is not easy to achieve a high degree of dispersion of noble metals in this type of method. For noble metal catalysts with high loads, the effect of this method is not ideal. Document 5 [P.Stonehart, M.Watanabe, USP5,208,207] introduces a method for preparing activated carbon-supported platinum-ruthenium-palladium three-component catalyst. First, the precursors of the three metals such as chloropalladium acid, chloroplatinic acid and ruthenium chloride are mixed, and then reduced to an opaque mixture with a reducing agent with weak reducing ability such as sodium thiosulfate, and then the carbon carrier is added and stirred vigorously A thick slurry is formed, and the solvent is evaporated by heating between 75 and 80 degrees to obtain a black powder, and then the black powder is dispersed, washed and filtered with water to obtain a three-component supported catalyst. Document 6 [MDMoser, RJLawson USP 4,677,094] introduces the preparation method of the catalyst used for the reforming of hydrocarbons to produce hydrogen. The simple process is to first prepare a supported platinum-tin alloy catalyst, and then impregnate ruthenium, cobalt, Rhenium, nickel, iridium and other elements. Compared with other catalysts, the catalyst is greatly improved in terms of activity and stability. Document 7 [W.Roh, J.Cho, H.Kim, J.Appl.Electrochem.26 (1996) 623] further impregnates base metals such as iron and copper on the basis of commercial Pt/C catalysts, and then undergoes high temperature treatment, Alloying platinum with iron and copper, the catalyst exhibits higher activity than Pt/C catalysts for the electrocatalytic reduction of oxygen in phosphoric acid fuel cells.

Technical content:

The invention provides a method for preparing an electrode catalyst, the electrode catalyst prepared by the method is suitable for various proton exchange membrane fuel cells, and is characterized in that:

The preparation process of the catalyst is carried out under the same solvent system, and the solvent is selected from one or more of C2 to C8 dihydric alcohols and trihydric alcohols, or its aqueous solution, wherein the volume percentage of water is 0-95% ; In the preparation process of the catalyst, the solvent plays the role of reducing agent, dispersant and protective agent;

The preparation process includes the following steps:

a, dissolving the precursor compound in the above-mentioned solvent;

B, prepare sodium hydroxide or potassium hydroxide solution with above-mentioned solvent;

c. Dispersing the carrier in the above solvent to prepare a carrier suspension;

d. Transferring the step a precursor solution to the step c carrier suspension;

f. Add the sodium hydroxide or potassium hydroxide solution in step b to the mixed solution in step d at -10 to 30°C, and adjust the pH value of the mixed solution to alkaline;

e. Under the protection of inert gas, keep at 40-250°C for 0.5-12 hours to reduce the temperature;

g, adjust pH to acidity with hydrochloric acid solution at 0～50°C;

h. The mixture is filtered, washed, and vacuum-dried at 40-200° C. to obtain a highly dispersed nanoscale supported Pt-based catalyst.

In the preparation method of the proton exchange membrane fuel cell electrode catalyst of the present invention, the solvent used is preferably ethylene glycol, or a mixed solution of ethylene glycol and water.

In the preparation method of the proton exchange membrane fuel cell electrode catalyst of the present invention, the pH value of the mixed solution adjusted in step f is preferably above 9; the pH value of the mixed solution adjusted in step g is preferably below 5.

In the preparation method of the proton exchange membrane fuel cell electrode catalyst of the present invention, step f is preferably carried out under the protection of an inert gas; ultrasonic dispersion can be used in step f; ultrasonic mixing can be used in step g.

The catalyst prepared by the method for preparing the proton exchange membrane fuel cell electrode catalyst of the present invention can be treated in various atmospheres at 60-1200° C. for 0.5-24 hours before use.

The catalyst prepared by the method of the present invention is not limited to Pt element, but can be based on Pt, and more other kinds of metals can be added to prepare Pt-based supported two-component multi-component nano-catalysts, and the method can be used to prepare anode catalysts and cathodes Catalysts, the carriers used all have good electrical conductivity, such as various carbon materials and other materials with certain electrical conductivity.

Compared with the prior art, the difference of the present invention is:

1. In the preparation of nano-Pt and its alloy catalysts in documents 1 and 3, it is necessary to first convert the chlorides of Pt and Ru into sulfurous acid compounds. Although this process can effectively eliminate the influence of trace chloride ions on catalytic performance, it is easy to cause Certain precious metal losses.

2. The method for preparing the catalyst in Document 2 is similar to that in Document 1, but there is no step of removing chloride ions in the middle, and the catalyst yield is relatively high. However, the degree of alloying of the two metals in the catalyst prepared by this method is not very high. The synergistic interaction is not strong, and the catalytic effect of noble metals on methanol and the like has not reached a very ideal level.

3. Document 4 uses borohydric acid quaternary ammonium salt NR ₄ BR ₃ H with a long carbon chain as a reducing agent and a protective agent to reduce platinum ruthenium and other transition metal precursors, and prepare nano-scale metals with a narrow particle size distribution range. colloid. This method requires an anhydrous and oxygen-free system, and the typical preparation process is completed in a tetrahydrofuran system. Although this method can prepare noble metal catalysts with very small particle sizes, since macromolecular organic substances are used as surface protection agents and reducing agents, and must be prepared in an anhydrous and oxygen-free system, the operation is cumbersome and the operating conditions are very harsh. Catalyst preparation The cost is high, and it is not suitable for mass production of catalysts. Compared with this method, the present invention does not use any macromolecular organic matter or other surface active agents, and does not need additional reducing agents. The operation is simple and the cost can be greatly reduced; while the prepared catalyst particles are still small.

4. The activated carbon-supported three-component catalyst prepared in Document 5 shows a good ability to resist CO, but this method uses sulfur-containing compounds as reducing agents in the preparation, and after the reduction is completed, it is not filtered in time Washing, but drying and then dispersing and washing, the intermediate reaction forms a variety of salts, especially various chlorides and sulfides, which are adsorbed and deposited on the activated carbon together, which is not easy to remove, and the existence of these substances is inevitable. Performance will be affected to some extent.

5. Although the impregnation method in Document 6 can prepare multi-component catalysts and show good catalytic activity, the impregnation method cannot prepare supported metal catalysts with a higher loading capacity. Compared with this method, the present invention can not only prepare low-loaded two-element, multi-element group-supported metal catalysts, but also prepare higher-loaded two-component, multi-element group-supported metal catalysts Metal catalysts, and can still ensure good dispersion of metals when the metal loading is high.

6. The catalyst prepared in Document 7 shows good activity for the electrocatalytic reduction of oxygen, but the promoter and the main catalytic component platinum metal are not added at the same time, but the promoter is added to the Pt/C that has been prepared. In order to ensure the formation of necessary alloys and realize the interaction between metals, the catalyst has to be treated at high temperature, which inevitably leads to sintering of precious metals and increases the radius of metal particles. utilization rate. Utilizing the method of the present invention can ensure that platinum and other various additives are carried on the carrier together in the initial preparation process, and the interaction between metals can be realized at a slightly lower temperature.

In general, the present invention can effectively reduce the diffusion rate of metal particles in the solution by changing the composition of the solvent in the dispersion system and increasing the viscosity of the solvent, preventing the metal particles from aggregating and increasing each other, while avoiding the use of macromolecular Surfactants can be used to prepare highly dispersed and high-content supported nano-scale Pt-based catalysts, which can greatly reduce the cost of preparing nano-catalysts. At the same time, various metals in the catalysts are closely combined and have obvious interactions. The anode catalyst prepared by this method shows good activity for electrocatalytic oxidation of low-carbon alcohol fuels such as methanol, ethanol, etc., and shows strong anti-CO ability for hydrogen/oxygen (air) PEMFCs; prepared by this method The cathodic catalyst has good electrocatalytic reduction activity for oxygen.

The invention can prepare highly dispersed and high-content nano-scale platinum-based electrode catalysts without using any surfactant or other organic protective agents. The cost of the solvent is low, the preparation is easy, the preparation process of the catalyst is simple and efficient, and the yield of the noble metal is high. Even if the prepared electrode catalyst has a high metal content, it can ensure a high degree of dispersion of the noble metal.

Using various carbon materials with good electrical conductivity such as various types of activated carbon, carbon fiber, and carbon nanotubes as carriers, the invention can prepare highly dispersed nano-scale Pt-based electrode catalysts, including various bicomponent and multicomponent electrode catalysts . Through the present invention, platinum and platinum/other metals can also be supported on other conductive materials to prepare electrode catalysts, which can be used to prepare both anode catalysts and cathode catalysts.

This type of Pt-based electrode catalyst loaded on a carbon carrier with good conductivity, such as various types of activated carbon, carbon fiber, carbon nanotube, etc., has been successfully applied to low-temperature fuel cell PEMFCs. The fuel can use various alcohol solutions, glucose, etc. solution, hydrogen, hydrogen/CO mixture, etc., showing good electrocatalytic activity and good resistance to CO.

In a word, the method of the present invention does not require pretreatment of the metal precursor, nor does it require any recognized surfactant or other polymeric organic matter as a protective agent to prepare a highly dispersed metal-supported catalyst with fine and uniform distribution, and the prepared supported catalyst The metal content can be as high as 90%.

Description of drawings:

Fig. 1 is the single cell performance figure (methanol is made fuel) when adopting the catalyst prepared by the present invention to make anode catalyst;

Single cell operating conditions:

Battery temperature: 90°C; Electrolyte membrane: Nafion-115; Electrode area: 9cm ² ;

Methanol concentration: 1 mole/liter; methanol flow rate: 1 ml/min; cathode (oxygen electrode) oxygen pressure: 2 atmospheres;

Cathode (oxygen electrode) catalyst: Pt/C (20Pt%, Johnson Matthey); noble metal dosage: 1mgPt/cm ² ;

Anode catalyst: PtRu/C (20Pt10Ru%); precious metal dosage: 2mgPtRu/cm ² ;

★: The anode uses a self-made catalyst PtRu/C (20Pt10Ru%, Example 1, curves 1 and 3);

●: The anode uses commercial catalyst PtRu/C (20Pt10Ru%, Johnson Matthey, curves 2 and 4).

Fig. 2 is the single cell performance figure (methanol is made fuel) when adopting the catalyst prepared by the present invention to make anode catalyst;

Single cell operating conditions:

Battery temperature: 75°C; Electrolyte membrane: Nafion-115; Electrode area: 9cm ²

Methanol concentration: 1 mole/liter, methanol flow rate: 1 ml/min; cathode (oxygen electrode) oxygen pressure: 2 atmospheres;

Cathode (oxygen electrode) catalyst: Pt/C (20Pt%, Johnson Matthey); noble metal dosage: 1mgPt/cm ² ;

Anode catalyst: PtRu/C (20Pt10Ru%); precious metal dosage: 2mgPtRu/cm ² ;

★: The anode uses a self-made catalyst PtRu/C (20Pt10Ru%, Example 1, curves 1 and 3);

●: The anode uses commercial catalyst PtRu/C (20Pt10Ru%, Johnson Matthey, curves 2 and 4).

Figure 3 adopts the single cell performance figure (methanol is made fuel) when the catalyst prepared by the present invention is used as the anode catalyst;

Single cell operating conditions:

Electrolyte membrane: Nafion-115; electrode area: 9cm ²

Methanol concentration: 1 mol/L; methanol flow rate: 1 ml/min;

Cathode (oxygen electrode) oxygen pressure: 2 atmospheres;

Cathode (oxygen electrode) catalyst: Pt/C (20Pt%, Johnson Matthey); noble metal dosage: 1mgPt/cm ² ;

Anode catalyst: self-made PtRu/C (60Pt30Ru%, embodiment 3); precious metal consumption: 2mgPtRu/cm ² ;

■: The current/voltage curve when the battery temperature is 25°C;

●: The current/voltage curve when the battery temperature is 75°C;

▲: The current/voltage curve when the battery temperature is 90°C.

Figure 4 adopts the single cell performance figure (methanol is made fuel) when the catalyst prepared by the present invention is used as the anode catalyst;

Single cell operating conditions:

Electrolyte membrane: Nafion-115; electrode area: 9cm ² :

Methanol concentration: 1 mole/liter; methanol flow rate: 1 ml/min; cathode (oxygen electrode) oxygen pressure: 2 atmospheres;

Cathode (oxygen electrode) catalyst: Pt/C (20Pt%, Johnson Matthey); noble metal dosage: 1mgPt/cm ² ;

Anode catalyst: self-made PtRu/C (40Pt20Ru%, embodiment 2); precious metal consumption: 2mgPtRu/cm ² ;

■: The current/voltage curve when the battery temperature is 25°C;

●: The current/voltage curve when the battery temperature is 75°C;

▲: The current/voltage curve when the battery temperature is 90°C.

When Fig. 5 adopts the catalyst prepared by the present invention as the anode catalyst, the single cell performance diagram (ethanol is used as fuel);

Single cell operating conditions:

Electrolyte membrane: Nafion-115; electrode area: 9cm ² ;

Ethanol concentration: 1 mole/liter, ethanol flow rate: 1 ml/min; cathode (oxygen electrode) oxygen pressure: 2 atmospheres;

Cathode (oxygen electrode) catalyst: Pt/C (20Pt%, Johnson Matthey); noble metal dosage: 1mgPt/cm ² ;

Anode catalyst; PtRu/C (20Pt10Ru% embodiment 1); precious metal consumption: 2mgPtRu/cm ² ;

●: Experimental results when the battery temperature is 90°C (1, 3);

★: Experimental results when the battery temperature is 75°C (2, 4).

Detailed ways:

The specific content of the technical solution of the embodiment of the present invention is as follows, certainly not limiting the present invention:

1. Selection of solvent: ethylene glycol, or a mixed solution of ethylene glycol and water, wherein the volume percentage of water is 0-95%.

2. Prepare the solution:

(1) Dissolving Pt precursor compounds such as chloroplatinic acid or potassium chloroplatinate into the solvent in the above 1 to prepare a solution with a content of 0.01-500 mgPt/ml. The precursor compounds of other metals are also dissolved with the solvent in the above 1 or directly with water, and the metal content in the solution is 0.01-500 mg/ml. These metals include ruthenium, tin, iridium, osmium, palladium, gold, silver, copper, iron, nickel, cobalt, chromium, molybdenum, tungsten, rhodium, and the like. Alternatively, according to the requirements for preparing the catalyst, the Pt precursor and other required metal precursors are dissolved in the same solvent to prepare a mixed solution according to the required metal ratio.

(2), utilize the solvent in above-mentioned 1, prepare sodium hydroxide or potassium hydroxide solution, its concentration is 0.01～4 mol/liter.

3. Dry the carrier in the air at 40-250°C for 0.5-24 hours before the test, mix with the solvent in the above 1 or directly with water (the solvent required for each mg of carrier is 0.01-1000 ml), and disperse by ultrasonic vibration for 5 ~60 minutes, the vehicle suspension was prepared. The carrier includes various carbon materials with good electrical conductivity, such as activated carbon, carbon nanotubes, carbon fibers, and other materials with certain electrical conductivity, or a mixture of the aforementioned carrier materials.

4. According to the requirements of the catalyst and the metal atomic ratio, measure the platinum precursor solution or other metal precursor solution prepared in the above 2 (preparation of a single-component catalyst), or mix two or more of them containing a single metal precursor Mix the solution of the body, or the mixed solution containing platinum and other metals (to prepare a two-component or multi-component catalyst), ultrasonically oscillate and mix for 5 to 180 minutes, and then transfer to the carrier suspension prepared in the above step 3 and ultrasonically oscillate for 5 After ~250 minutes, stir for 0.5~24 hours under the protection of inert gas.

5. Add an appropriate amount of sodium hydroxide or potassium hydroxide solution in the above 3 to the mixed solution prepared in step 4 at -10-30°C under the protection of an inert gas, and adjust the pH value of the mixed solution to alkaline, especially If it is above 9, mix by ultrasonic oscillation for 5 to 600 minutes. Stir for 0.5 to 24 hours under the protection of an inert gas, and keep at 40 to 250° C. for 0.5 to 12 hours to reduce the temperature.

6. Adjust pH to acidity with hydrochloric acid solution at 0-50°C, especially below 5, stir for 0.5-24 hours, or keep at 50-170°C for 0.5-24 hours to promote sedimentation. The mixture is filtered, washed with a large amount of hot deionized water, and vacuum-dried at 40-200° C. to obtain a highly dispersed nanoscale supported Pt-based catalyst.

7. Various platinum-based catalysts prepared in the above steps can be treated in various atmospheres at 60-1200°C for 0.5-24 hours, such as oxidizing atmosphere, reducing atmosphere, inert gas, etc. It can also be used directly without treatment.

9. Apply the supported platinum-based catalyst prepared in the above steps, especially the catalyst loaded on various carbon materials, to various supports such as carbon paper, carbon cloth, etc. according to the procedures for preparing electrodes, and mix with various solid electrolytes 80-240°C, hot pressing at 2-50 atmospheres for 10-1000 seconds to make a membrane electrode assembly (MEA) and assemble it into a battery.

10. Various fuels such as various alcohol or glucose solutions, hydrogen, hydrogen/CO mixed gas, hydrogen and other gas mixtures are passed through the anode side of the above battery, and oxygen or air is passed through the cathode side. Discharge at 170°C.

Embodiment 1: the preparation of PtRu/C (20Pt10Ru%) anode catalyst

Activated carbon XC-72R was pre-treated with 5mol/L nitric acid solution, dried at 200°C for 4 hours, weighed 500 mg and dispersed it with 25 ml of ethylene glycol and water mixed solvent (wherein the volume content of water was 5%) for 30 carbon paste in minutes. Measure 19.5 milliliters of chloroplatinic acid/ethylene glycol solution (7.4 mg platinum/ml), measure ruthenium trichloride/ethylene glycol+water solution (wherein the volume content of water is 10%, 6.4 mg ruthenium/ml) 11.2 milliliters mix , ultrasonically oscillated for 20 minutes, then added dropwise to the carbon slurry, and stirred for 10 hours with argon deoxygenation, then added dropwise 15 ml of 1 mol/L sodium hydroxide/ethylene glycol solution, continued to stir for 5 hours, and then raised the temperature to 185°C Keep it for 4 hours, then lower the temperature to 25°C, adjust the pH value to 3 with 1 mol/L dilute hydrochloric acid aqueous solution, stir for 3 hours, then filter, the filtrate is clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a 20%Pt-10Ru% catalyst with a yield of 98.8%. The experimental results of transmission electron microscopy and X-ray diffraction show that the particle size of the bicomponent noble metal is below 2.5 nanometers.

Embodiment 2: the preparation of PtRu/C (40Pt20Ru%) anode catalyst

Activated carbon XC-72R was pre-treated with 5mol/L nitric acid solution, dried at 200°C for 4 hours, weighed 500 mg, and dispersed it by ultrasonic vibration for 30 milliliters with a mixed solvent of ethylene glycol and water (wherein the volume content of water was 5%) carbon paste in minutes. Measure 25 milliliters of chloroplatinic acid/ethylene glycol solution (20 mg platinum/ml), measure 25 milliliters of ruthenium trichloride/ethylene glycol+water solution (wherein the volume content of water is 10%, 10 mg ruthenium/ml) mix , after ultrasonic vibration for 20 minutes, drop it into the carbon slurry, argon deoxygenation and stirring for 10 hours, then add 15 ml of 1 mol/L sodium hydroxide/ethylene glycol solution dropwise, continue stirring for 5 hours, then raise the temperature to 180°C Keep it for 4 hours, then lower the temperature to 25°C, adjust the pH value to 2.5 with 1.5 mol/L dilute hydrochloric acid aqueous solution, stir for 5 hours, and filter, the filtrate is clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a 40%Pt-20Ru% catalyst. The yield is 93%. The experimental results of transmission electron microscope and X-ray diffraction show that the particle size of the bicomponent noble metal is below 3.0 nanometers.

Embodiment 3: the preparation of PtRu/C (60Pt30Ru%) catalyst

Activated carbon XC-72R was pre-treated with 5mol/L nitric acid solution, dried at 200°C for 4 hours, weighed 200 mg, and dispersed it by ultrasonic vibration for 30 milliliters of a mixed solvent of ethylene glycol and water (wherein the volume content of water was 5%) carbon paste in minutes. Measure 24 ml of chloroplatinic acid/ethylene glycol solution (50 mg platinum/ml), measure 20 ml of ruthenium trichloride/ethylene glycol (30 mg ruthenium/ml) and mix, ultrasonically oscillate for 50 minutes and add dropwise to carbon In the slurry, after argon deoxygenation and stirring for 10 hours, 10 ml of 2 mol/liter sodium hydroxide/ethylene glycol solution was added dropwise, stirring was continued for 5 hours, then the temperature was raised to 180°C and kept for 6 hours, and then cooled to 25°C. Adjust the pH value to 2.5 with 1.5 mol/L dilute hydrochloric acid aqueous solution, stir for 5 hours, filter, and the filtrate is clear and transparent. The solid was vacuum-dried at 70° C. for 8 hours to obtain a catalyst with 60% Pt-30Ru%, with a yield of 86%. The results of transmission electron microscopy and X-ray diffraction experiments showed that the particle size of the bicomponent noble metal was below 3.0 nanometers.

Embodiment 4: the preparation of PtRu/carbon nanotube (20Pt10Ru%) catalyst

The carbon nanotubes are pre-treated with sulfuric acid. After drying at 200° C. for 4 hours, 500 mg was weighed and dispersed with 25 ml of a mixed solvent of ethylene glycol and water (the volume content of water was 5%) for 30 minutes by ultrasonic vibration to prepare a suspension of carbon nanotubes. Measure 19.5 milliliters of chloroplatinic acid/ethylene glycol solution (7.4 mg platinum/ml), measure ruthenium trichloride/ethylene glycol+water solution (wherein the volume content of water is 5%, 6.4 mg ruthenium/ml) 11.2 milliliters mix , ultrasonically oscillated for 20 minutes and then added dropwise to the suspension of carbon nanotubes. After argon deoxygenation and stirring for 10 hours, 15 ml of 1 mol/liter sodium hydroxide/ethylene glycol solution was added dropwise, and the temperature was raised after continuing to stir for 5 hours. Keep at 185°C for 4 hours, then lower the temperature to 25°C, adjust the pH value to 3 with 1 mol/L dilute hydrochloric acid aqueous solution, stir for 3 hours, then filter, the filtrate is clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a 20%Pt-10Ru% catalyst. The yield is 95%. The experimental results of transmission electron microscope and X-ray diffraction show that the particle size of the bicomponent noble metal is below 3.0 nanometers.

Embodiment 5: Preparation of PtCo/C (20Pt%, Pt/Co=2: 1) cathode catalyst

Activated carbon XC-72R was pre-dried at 200°C for 4 hours, weighed 500 mg and dispersed with 25 ml of a mixed solvent of ethylene glycol and water (wherein the volume content of water was 4%) for 30 minutes with ultrasonic vibration to prepare a carbon slurry. Measure 19.5 ml of chloroplatinic acid/ethylene glycol solution (7.4 mg platinum/ml), measure 11.0 ml of cobalt nitrate/ethylene glycol+water solution (wherein the volume content of water is 5%, 7.0 mg cobalt/ml) and mix, ultrasonic After shaking for 40 minutes, add it dropwise into the carbon slurry. After stirring for 10 hours with argon gas deoxygenation, add 10 ml of 1.5 mol/liter sodium hydroxide/ethylene glycol solution dropwise, continue stirring for 16 hours, then raise the temperature to 185°C and keep for 6 hours. hour, then lower the temperature to 25°C, adjust the pH value to 3 with 1 mol/L dilute hydrochloric acid aqueous solution, stir for 8 hours, and filter, the filtrate is clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a PtCo/C catalyst. The yield is 97.7%. The experimental results of transmission electron microscopy and X-ray diffraction show that the size of the bicomponent metal particles is below 3.0 nanometers.

Embodiment 6: the preparation of Pt/C (20Pt%) electrode catalyst

Activated carbon XC-72R was pre-dried at 200°C for 10 hours, weighed 600 mg and dispersed it with 60 ml of a mixed solvent of ethylene glycol and water (where the volume content of water was 10%) for 50 minutes to obtain a carbon slurry. Measure 15 milliliters of chloroplatinic acid/ethylene glycol solution (10.0 mg platinum/ml), add it dropwise to the carbon slurry, and after stirring for 12 hours with argon deoxygenation, add 1.0 mol/liter of sodium hydroxide/ethylene glycol dropwise 5 ml of alcoholic solution, continue to stir for 16 hours, then raise the temperature to 170°C and keep for 3 hours, then cool down to room temperature, adjust the pH value to 3.5 with 0.2 mol/L dilute hydrochloric acid aqueous solution, stir for 8 hours, filter, and the filtrate is clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a PtCo/C catalyst. The yield is 97.0%. The experimental results of transmission electron microscope and X-ray diffraction show that the size of the bicomponent metal particles is below 3.0 nanometers.

Embodiment 7: the preparation of PtRuIr/C (20Pt%, Pt/Ru/Ir=2: 1: 1) catalyst

Activated carbon XC-72R was pre-dried at 200°C for 4 hours, weighed 650 mg and dispersed it with 40 ml of ethylene glycol for 30 minutes with ultrasonic vibration to prepare carbon slurry. Measure 27 milliliters of chloroplatinic acid/ethylene glycol+water solution (wherein the volume content of water is 2%, 7.4 mg platinum/ml), measure 5.8 ml of ruthenium trichloride/ethylene glycol (9 mg ruthenium/ml) and mix, Measure 16.5 milliliters of chloroiridic acid/ethylene glycol+water solution (wherein the volume content of water is 10%, 6 mg iridium/ml), ultrasonically oscillate for 30 minutes, add dropwise to the carbon slurry, and stir for 10 hours with argon deoxygenation , add dropwise 15 ml of 1 mol/L sodium hydroxide/ethylene glycol solution, continue stirring for 12 hours, then raise the temperature to 180°C and keep it for 8 hours, then cool down to 25°C, and adjust the pH value with 1.5 mol/L dilute hydrochloric acid aqueous solution To 3.5, after stirring for 5 hours, filter, and the filtrate is clear and transparent. The solid was vacuum dried at 70° C. for 8 hours to obtain a 20% Pt-5.2Ru%-10% catalyst (35% total metal content). The yield is 98%. The experimental results of transmission electron microscope and X-ray diffraction show that the particle size of the three-component noble metal is below 2.5 nanometers.

Embodiment 8: Preparation of PtCuFe/C (20Pt%, Pt/Cu/Fe=2:1:1) cathode catalyst

Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol (7.4 mg Pt/mL), dissolve 0.236 g of CuSO ₄ 5H ₂ O and 0.256 g of FeCl ₃ 6H ₂ O in 10 mL of deionized water, and dissolve the two The two solutions were mixed and dispersed by ultrasonic vibration for 120 minutes. Activated carbon XC-72R was pre-dried at 200°C for 10 hours, weighed 1.36 g and dispersed with 100 ml of a mixed solvent of ethylene glycol and water (wherein the volume content of water was 10%) for 60 minutes by ultrasonic oscillation to prepare a carbon slurry. Add the metal mixed solution dropwise into the carbon slurry, and stir for 10 hours with argon gas deoxygenation, then add 15 ml of 1.0 mol/liter sodium hydroxide/ethylene glycol solution dropwise, continue stirring for 16 hours, then raise the temperature to 170°C and keep 4 hours, then lowered to room temperature, adjusted the pH value to 3.5 with 0.2 mol/L dilute hydrochloric acid aqueous solution, then raised the temperature to 80°C and stirred for 8 hours, then filtered, and the filtrate was clear and transparent. The solid was vacuum dried at 70°C for 8 hours to obtain a PtCuFe/C cathode catalyst. The yield is 98.7%. The experimental results of transmission electron microscopy and X-ray diffraction show that the size of the bicomponent metal particles is below 3.0 nanometers.

Embodiment 9: Preparation of PtNi/carbon nanotube (20Pt10Ni%) catalyst

The carbon nanotubes are pre-treated with sulfuric acid. After drying at 200° C. for 4 hours, 500 mg was weighed and dispersed with 25 ml of a mixed solvent of glycerol and water (wherein the volume content of water was 20%) for 30 minutes by ultrasonic vibration to prepare a suspension of carbon nanotubes. Measure 19.5 milliliters of the mixed solution of chloroplatinic acid/glycerol and water (wherein the volume content of water is 10%, 7.4 mg platinum/ml), measure the mixed solution of nickel nitrate/glycerol and water (wherein the volume content of water The volume content is 10%, 8 mg nickel/ml) and 9 ml are mixed, ultrasonically oscillated for 50 minutes, and then added dropwise to the carbon nanotube suspension. 15 ml of sodium/ethylene glycol solution, continue to stir for 5 hours, then raise the temperature to 175°C and keep it for 5 hours, then cool down to 25°C, adjust the pH value to 3.5 with 1 mol/liter of dilute hydrochloric acid aqueous solution, stir for 5 hours, filter, The filtrate was clear and transparent. The solid was vacuum dried at 70° C. for 8 hours to obtain a 20% Pt-10Ni% catalyst. The yield is 95%. The experimental results of transmission electron microscope and X-ray diffraction show that the particle size of the bicomponent noble metal is below 3.0 nanometers.

Embodiment 10: the application embodiment of the prepared catalyst on the fuel cell

The PtRu/C catalyst prepared in Examples 1-9 was used as the anode catalyst of DMFCs, and a single cell was assembled. For example, the catalyst prepared in Example 1 is used as the oxygen catalyst for single-cell experiments: 67 mg of Pt-Ru/C (20Pt%wt, 10Ru%wt) weighed by a balance is mixed with an appropriate amount of H ₂ O and ethanol, and then 5% 150 mg of Nafion was uniformly oscillated by ultrasonic waves, and then coated on a 10 cm ² support layer to prepare an anode, in which the total content of precious metals was 2 mg/cm ² . Use a balance to weigh 50 mg of Pt/C catalyst (Johnson Matthey commercial catalyst) with a content of 20% wt, mix it with an appropriate amount of H ₂ O and ethanol, add 62.5 mg of 20% polytetrafluoroethylene PTFE aqueous solution, and after ultrasonic vibration is uniform, apply onto a support layer of 10 cm ² , the cathode was made. The surfaces of the prepared cathode and anode catalytic layers were sprayed with 5% Nafion solution at a dosage of 1 mg/cm ² . Then heat-press with Nafion115 membrane at 130°C for 90 seconds to obtain a membrane-electrode assembly. Place one or several stainless steel meshes on both sides of the membrane-electrode assembly to assemble a single cell. The two pole plates of the battery are stainless steel plates, and the effective area of the battery is 9cm ² . Aqueous methanol solution was passed into the anode side with a concentration of 1mol/L and a flow rate of 1ml/min. Oxygen is fed into the cathode side, and the pressure is 0.2MPa. After raising the temperature of the battery to 75°C with a heating rod inserted into the two plates, the discharge operation was started. After the discharge performance of the battery is stable, measure the voltage/current density curve of the battery. Its performance curve is shown in the accompanying drawing. In addition, Johnson Matthey's commercial catalyst PtRu/C (20Pt%wt, 10Ru%wt) was used as the anode electrocatalyst, and the anode was prepared according to the above steps, and a single cell was assembled for a comparative test.

Claims (7)

1, a kind of preparation method of proton exchange membrane fuel cell electrode catalyst, it is characterized in that: The preparation process of the catalyst is carried out under the same solvent system, and the solvent is ethylene glycol, glycerin or an aqueous solution thereof, wherein the volume percentage of water is 0-10%; The preparation process includes the following steps: a. Dissolve Pt and other metal components including precursor compounds of ruthenium, iridium, osmium, palladium, gold, silver, copper, iron, nickel, cobalt, chromium, molybdenum, rhodium in the above solvent, or copper, iron The precursor compound is directly dissolved in water, the content of Pt in the solution is 0.01-500mg/ml, and the content of other metals is 0.01-500mg/ml; B, prepare sodium hydroxide or potassium hydroxide solution with above-mentioned solvent, its concentration is 0.01～4 mol/liter; c. Dispersing the carbon material carrier with good conductivity in the above solvent to prepare carrier suspension; d. Transferring the step a precursor solution to the step c carrier suspension; f. Add the sodium hydroxide or potassium hydroxide solution prepared in step b to the mixed solution in step d at -10 to 30°C, and adjust the pH of the mixed solution to alkaline; e. Under the protection of inert gas, keep at 40-250°C for 0.5-12 hours to reduce the temperature; g, adjust the pH value to acidity with hydrochloric acid solution at 0～50°C; h, the mixture is filtered, washed, and vacuum-dried at 40 to 200° C. to obtain a highly dispersed nanoscale supported Pt-based catalyst; The above-mentioned preparation processes are all carried out under stirring. 2. The method for preparing the proton exchange membrane fuel cell electrode catalyst according to claim 1, characterized in that in step f, the pH value of the mixed solution is adjusted to be above 9. 3. The method for preparing the proton exchange membrane fuel cell electrode catalyst according to claim 2, characterized in that in step g, the pH value of the mixed solution is adjusted to below 5. 4. The method for preparing the proton exchange membrane fuel cell electrode catalyst according to claim 1, characterized in that step f is carried out under the protection of an inert gas. 5. The method for preparing an electrode catalyst for a proton exchange membrane fuel cell according to claim 1, wherein ultrasonic dispersion is used in step f. 6. The method for preparing an electrode catalyst for a proton exchange membrane fuel cell according to claim 1, wherein ultrasonic mixing is used in step g. 7. The preparation method of the proton exchange membrane fuel cell electrode catalyst according to claim 1, characterized in that: before use, the prepared platinum-based catalyst is treated at 60-1200° C. for 0.5-24 hours.

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