TaOx modified platinum-based catalyst as well as preparation method and application thereof

Abstract

The invention provides a TaOx modified platinum-based catalyst as well as a preparation method and application thereof. The TaOx modified platinum-based catalyst comprises a platinum-based catalyst and TaOx loaded on the platinum-based catalyst, the loading amount of Ta in the TaOx modified platinum-based catalyst is 5 wt% to 50 wt%. The TaOx / Pt composite catalyst has the advantages that the anti-poisoning ability of the catalyst is improved by utilizing the interaction of TaOx and Pt, the problems of curing and agglomeration of Pt under a fuel cell cycling stability test are effectively inhibited, and the improvement of the activity and the stability of the catalyst is realized. In addition, the raw materials of the TaOx modified commercial platinum-based catalyst material prepared in the invention are common and easy to obtain, the reaction steps are simple, the reaction conditions are mild, and the applicability is wide.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cell technology, and particularly relates to a TaO x Modified platinum-based catalyst, preparation method and application thereof. Background Art

[0002] Proton exchange membrane fuel cells (PEMFCs) are electrochemical energy conversion devices that directly convert the chemical energy in hydrogen and oxygen into electrical energy. They have the advantages of zero pollution emissions and efficient fuel utilization during operation, making them have great application potential in the fields of transportation, distributed power generation and portable power. However, their large-scale commercialization still faces two core challenges: high cost and low durability. Although platinum-based catalysts have excellent ORR activity, platinum will be poisoned by sulfonate groups in the ionomer; and under the harsh operating conditions of fuel cells, platinum particles often undergo dissolution migration, Ostwald ripening and agglomeration, resulting in a significant decrease in performance. This instability of platinum and its high cost seriously restrict the lifespan and economic feasibility of PEMFCs, hindering their widespread application. Summary of the Invention

[0003] The purpose of the present invention is to provide a TaO x Modified platinum-based catalyst, its preparation method and application, TaO in the present invention x Modified platinum-based catalysts can improve the activity and cycling stability of fuel cells.

[0004] The present invention provides a TaO x Modified platinum-based catalysts, including platinum-based catalysts and TaO supported on platinum-based catalysts x ;

[0005] The TaO x The loading amount of Ta in the modified platinum-based catalyst is 5wt% to 50wt%.

[0006] Preferably, the platinum-based catalyst comprises a carbon support and platinum supported on the carbon support, and the loading amount of platinum in the platinum-based catalyst is 10 wt% to 50 wt%.

[0007] Preferably, the TaO x In the modified platinum-based catalyst, the mass ratio of Ta element to platinum element is (0.2-5):1.

[0008] The present invention provides TaO as described above x The preparation method of the modified platinum-based catalyst comprises the following steps:

[0009] A) dispersing a platinum-based catalyst in a first solvent to obtain a catalyst dispersion; and dispersing a tantalum compound in a second solvent to obtain a tantalum source solution;

[0010] B) adding the tantalum source solution dropwise to the catalyst dispersion to react, and drying the solution after the reaction to obtain an intermediate;

[0011] C) heat-treating the intermediate in a reducing atmosphere to obtain TaO x Modified platinum-based catalysts.

[0012] Preferably, the tantalum compound includes one or more of tantalum pentachloride, tantalum nitrate and tantalum pentaethoxide.

[0013] Preferably, in step B), the tantalum source solution is added dropwise to the catalyst dispersion, and ultrasonication and stirring are sequentially performed to carry out the reaction;

[0014] The ultrasonication time is 0.5 to 3 hours, and the stirring time is 6 to 24 hours.

[0015] Preferably, in step B), the reaction temperature is 20-30° C., and the reaction time is 6.5-27 hours.

[0016] Preferably, in step C), the reducing atmosphere comprises a reducing gas and an inert gas, and the volume fraction of the reducing gas in the reducing atmosphere is 2 to 10%.

[0017] Preferably, in step C), the heat treatment temperature is 300-1000° C., the heat treatment holding time is 0.5-3 hours, and the heat treatment heating rate is 1-20° C. / min.

[0018] The present invention provides TaO as described above x Application of modified platinum-based catalysts as cathode catalysts in proton exchange membrane fuel cells.

[0019] The present invention provides a TaO x Modified platinum-based catalysts, including platinum-based catalysts and TaO supported on platinum-based catalysts x ; the TaO x The loading amount of Ta in the modified platinum-based catalyst is 5 wt% to 50 wt%. x The interaction with Pt improves the anti-poisoning ability of the catalyst and effectively inhibits the ripening and agglomeration of Pt in the fuel cell cycle stability test, thereby improving the activity and stability of the catalyst. x The raw materials for modifying commercial platinum-based catalyst materials are common and easily available, and the reaction steps are simple, the reaction conditions are mild, and the applicability is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0021] Figure 1 Graphs showing the IV polarization curves of the commercial catalyst in Comparative Example 1 of the present invention at the initial stage and after 30,000 cycles of cyclic stability testing;

[0022] Figure 2 The CO stripping voltammetry curves of the commercial catalyst in Comparative Example 1 of the present invention are the initial and 30,000 cycle stability tests;

[0023] Figure 3 TaO prepared in Example 1 of the present invention x Modified X-ray powder diffraction patterns of commercial platinum-based catalyst materials;

[0024] Figure 4 TaO prepared in Example 1 of the present invention x Scanning transmission electron micrograph of modified commercial platinum-based catalyst material;

[0025] Figure 5 TaO prepared in Example 1 of the present invention x IV polarization curves of modified commercial platinum-based catalyst materials initially and after 30,000 cycles of cycling stability testing;

[0026] Figure 6 TaO prepared in Example 1 of the present invention x CO stripping voltammograms of the modified commercial platinum-based catalyst material initially and after 30,000 cycles of cycling stability testing;

[0027] Figure 7 Graphs of IV polarization curves of the commercial catalyst in Comparative Example 2 of the present invention at the initial stage and after 30,000 cycles of cyclic stability testing;

[0028] Figure 8 The CO stripping voltammetry curves of the commercial catalyst in Comparative Example 2 of the present invention are the initial and 30,000 cycle stability tests;

[0029] Figure 9 TaO prepared in Example 2 of the present invention x Modified X-ray powder diffraction patterns of commercial platinum-based catalyst materials;

[0030] Figure 10 TaO prepared in Example 2 of the present inventionx Scanning transmission electron micrograph of modified commercial platinum-based catalyst material;

[0031] Figure 11 TaO prepared in Example 2 of the present invention x IV polarization curves of modified commercial platinum-based catalyst materials initially and after 30,000 cycles of cycling stability testing;

[0032] Figure 12 The TaO prepared in Example 2 of the present invention x CO stripping voltammograms of the modified commercial Pt-based catalyst material initially and after 30,000 cycles of cycling stability testing. DETAILED DESCRIPTION

[0033] The present invention provides a TaO x Modified platinum-based catalyst (TaO x -Pt / C), including platinum-based catalysts and TaO supported on platinum-based catalysts x ;

[0034] The TaO x The loading amount of Ta in the modified platinum-based catalyst is 5wt% to 50wt%.

[0035] In the present invention, the platinum-based catalyst preferably includes a carbon support and platinum supported on the carbon support, and the platinum loading in the platinum-based catalyst is 10 wt% to 50 wt%, more preferably 20 wt% to 40 wt%. Specifically, in some embodiments of the present invention, the platinum-based catalyst can be a commercially available catalyst, such as one or more of the TKK series (models such as TEC10E30E, TEC10V50E, etc.), Johnson Matthey series (models such as Hispec4000, Hispec9100, etc.), Umicore series (models such as Elyst Pt500550, Elyst Pt20 0390, etc.), Premetek series (20% Pt on Vulcan XC-72, etc.), etc.

[0036] In the present invention, the TaO x , 0<x≤2.5. The TaO x The loading amount of Ta in the modified platinum-based catalyst is 5 wt% to 50 wt%, more preferably 10 to 40 wt%, such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, preferably a range value with any of the above values ​​as the upper or lower limit. In the present invention, the "loading amount" refers to the mass percentage of the catalytically active substance in the catalyst, such as "TaOx The Ta loading amount in the modified Pt-based catalyst refers to the mass of Ta element as a percentage of TaO x The percentage of modified platinum-based catalyst by mass.

[0037] In the present invention, the TaO x In the modified platinum-based catalyst, the mass ratio of Ta element to platinum element is (0.2-5):1, more preferably (0.5-4.5):1, such as 0.2:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, preferably a range value with any of the above values ​​as the upper or lower limit.

[0038] The present invention also provides the TaO x The preparation method of the modified platinum-based catalyst comprises the following steps:

[0039] A) dispersing a platinum-based catalyst in a first solvent to obtain a catalyst dispersion; and dispersing a tantalum compound in a second solvent to obtain a tantalum source solution;

[0040] B) adding the tantalum source solution dropwise to the catalyst dispersion to react, and drying the solution after the reaction to obtain an intermediate;

[0041] C) heat-treating the intermediate in a reducing atmosphere to obtain TaO x Modified platinum-based catalysts.

[0042] The present invention preferably mixes a platinum-based catalyst and a first solvent, stirs and mixes them at room temperature for 5 to 20 minutes to obtain a catalyst dispersion, then drops a tantalum source solution into the catalyst dispersion, ultrasonicates the mixture for 0.5 to 3 hours, and stirs and reacts for 6 to 24 hours to obtain a catalyst intermediate loaded with a tantalum compound.

[0043] In the present invention, the tantalum source solution includes a tantalum compound and a second solvent, and the tantalum compound preferably includes one or more of tantalum pentachloride, tantalum nitrate and tantalum pentaethanoloxide; the second solvent is preferably an alcohol solvent and / or deionized water, and the alcohol solvent is preferably one or more of anhydrous ethanol, isopropanol, n-propanol and n-butanol; the first solvent is preferably an alcohol solvent and / or deionized water, and the alcohol solvent is preferably one or more of anhydrous ethanol, isopropanol, n-propanol and n-butanol; the first solvent and the second solvent may be the same or different. In one embodiment of the present invention, the first solvent and the second solvent are the same.

[0044] In the present invention, the oxygen in the tantalum compound, or the tantalum compound and the oxygen in the alcohol solvent and / or water form an oxygen-containing compound, so that TaO can be obtained in the subsequent heat treatment in a reducing atmosphere.x Modified platinum-based catalysts.

[0045] In the present invention, the concentration of the tantalum source solution is preferably 2 to 20 mg / mL, more preferably 5 to 15 mg / mL, such as 2 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, preferably a range value with any of the above values ​​as the upper or lower limit; the concentration of the catalyst dispersion is preferably 1 to 5 mg / mL, more preferably 2 to 4 mg / mL, such as 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL. L, 5 mg / mL, preferably a range value with any of the above numerical values ​​as the upper or lower limit, the mass ratio of tantalum in the tantalum compound to platinum in the platinum-based catalyst is preferably (0.2-5):1, more preferably (0.5-4.5):1, such as 0.2:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, preferably a range value with any of the above numerical values ​​as the upper or lower limit.

[0046] In the present invention, the reaction time is preferably 8 to 20 hours, more preferably 10 to 12 hours; the reaction temperature is preferably room temperature, such as 20 to 30°C.

[0047] After the reaction is completed, the present invention dries the reaction solution to obtain a dry intermediate powder. The drying can be rotary vacuum drying or heating drying. The drying can be performed using a rotary vacuum evaporator commonly used in the art or under heating and stirring conditions. The present invention does not impose any special restrictions on this.

[0048] After obtaining the intermediate powder, the present invention places the intermediate powder in a tube furnace and performs heat treatment under a reducing atmosphere to obtain TaO x Modified platinum-based catalysts.

[0049] In the present invention, the reducing atmosphere comprises a reducing gas and an inert gas. The reducing gas preferably comprises hydrogen, and the inert gas preferably comprises nitrogen and / or argon. The volume fraction of the reducing gas in the reducing atmosphere is preferably 2 to 10%, more preferably 3 to 8%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, preferably within a range with any of the above values ​​as the upper or lower limit. The reducing atmosphere can promote the interaction between tantalum and the catalyst support.

[0050] In the present invention, the temperature of the heat treatment is preferably 300-1000°C, more preferably 400-900°C, such as 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, preferably a range value with any of the above numerical values ​​as the upper or lower limit; the holding time of the heat treatment is preferably 0.5-3 hours, more preferably 1-2 hours; the heating rate of the heat treatment is preferably 1-20°C / min, more preferably 3-15°C / min, such as 1°C / min, 3°C / min, 5°C / min, 10°C / min, 15°C / min, 20°C / min, preferably a range value with any of the above numerical values ​​as the upper or lower limit, and during the heat treatment process, the tubular furnace is maintained at normal pressure.

[0051] After the heat treatment, the mixture was cooled to room temperature to obtain TaO x Modified commercial platinum-based catalyst.

[0052] The present invention also provides the TaO x Application of modified commercial platinum-based catalysts as cathode catalysts in proton exchange membrane fuel cells.

[0053] In some embodiments of the present application, commercial platinum-based catalysts and the TaO x The modified platinum-based catalyst was subjected to IV polarization curve test and cycle stability test; the stability test was conducted using a commercial fuel cell test system, with a potential range of 0.6-0.95V, using a square wave step method, switching the potential every three seconds, and performing 30,000 cycles. x The modified platinum-based catalyst material performed well in electrochemical tests, with significant improvements in activity and stability. It effectively alleviated platinum poisoning and platinum agglomeration and sintering in stability tests, and has good application prospects.

[0054] In addition, the TaO prepared in this application x The raw materials for modifying commercial platinum-based catalyst materials are common and easily available, and the reaction steps are simple, the reaction conditions are mild, and the applicability is wide.

[0055] In order to further illustrate the present invention, the following embodiments are combined to describe a TaO x The modified platinum-based catalyst, its preparation method and application are described in detail, but it should not be understood as limiting the scope of protection of the present invention.

[0056] The raw materials in the following examples are all commercially available products.

[0057] Comparative Example 1

[0058] The commercial Pt / C catalyst of the TKK series, model TEC10E30E, was used as the cathode catalyst of a proton exchange membrane fuel cell. The commercial Pt / C catalyst of the TKK series, model TEC10E30E, was used as the anode catalyst of a proton exchange membrane fuel cell. The IV polarization curve test and the cycle stability test were conducted. The experimental steps are as follows:

[0059] a 30mg commercially available TEC10E30E catalyst was dispersed in water, isopropanol, Nafion solution, ultrasonicated for 6h to obtain a catalyst slurry having a slurry concentration of 2.5mg / ml;

[0060] b. Spray the above ink to 5cm by ultrasonic spraying equipment 2 As cathode catalyst on the proton exchange membrane; Pt loading is 0.1 mg Pt / cm 2 ;

[0061] c. Spray the TEC10E30E catalyst slurry to 5cm by ultrasonic spraying equipment. 2 On the proton exchange membrane, as the anode catalyst, the Pt loading is 0.05 mg Pt / cm 2 .

[0062] The IV polarization curve test was carried out in a single cell using a commercial fuel cell test system. The test conditions were: cell operating temperature 94°C, back pressure 250kPa abs , humidity 65RH%; hydrogen was passed through the anode at a flow rate of 0.5L / min; air was passed through the cathode at a flow rate of 2L / min.

[0063] The electrochemical active area test was conducted in a single cell using a commercial fuel cell test system. The test conditions were: cell operating temperature 80°C, back pressure 150kPa abs , humidity 100RH%; nitrogen was passed through the anode, carbon monoxide was first passed through the cathode for adsorption, and then nitrogen was passed through the cathode for purging. The CO stripping voltammogram was recorded at a scan rate of 100mV / s, and the electrochemical active area was calculated based on this.

[0064] Cycling stability testing was conducted using a commercial fuel cell test system at an operating temperature of 80°C and a humidity of 100%. Hydrogen was passed through the anode at a flow rate of 0.2 L / min, and nitrogen was passed through the cathode at a flow rate of 0.2 L / min. A square wave step method was used within the potential range of 0.6 to 0.95 V, switching the potential every three seconds for 30,000 cycles to accelerate catalyst degradation. The 30,000 cycles were performed within the potential range of 0.6 to 0.95 V.

[0065] Figure 1Graphs showing the IV polarization curves of the commercial catalyst in comparative example 1 of the present invention at the initial stage and after 30,000 cycles of cyclic stability testing.

[0066] Figure 2 The CO stripping voltammetry curves of the commercial catalyst in Comparative Example 1 of the present invention are the initial and 30,000 cycle stability tests.

[0067] Depend on Figure 1 and Figure 2 The results show that the untreated commercial catalyst is unstable in the electrochemical test, with large attenuation in the polarization curve and CO stripping voltammetry curve.

[0068] Example 1

[0069] a. Disperse 50 mg of a commercial TKK series Pt / C catalyst (model TEC10E30E) in 30 mL of anhydrous ethanol. After stirring at room temperature for 5 minutes, add 24.7 mg of tantalum chloride solution dissolved in 5 mL of anhydrous ethanol. Ultrasonicate the resulting solution for 1 hour and continue stirring at room temperature for 12 hours.

[0070] b. The above solution was evaporated in a rotary vacuum evaporator to obtain a dry powder and transferred to a tube furnace; reduced in a hydrogen / argon gas mixture with a volume fraction of 5%, the heating rate was controlled at 5°C / min, the temperature was raised to 900°C, the holding time was 1h, and finally cooled naturally to room temperature. The tube furnace was always maintained at atmospheric pressure.

[0071] According to the formula: Tawt%=m(Ta) / m(Ta+Pt+C), the loading amount of tantalum on the commercial catalyst in this embodiment is 20wt%.

[0072] For the TaO obtained in Example 1 x A commercial platinum-based catalyst material was modified and used as the cathode catalyst in a proton exchange membrane fuel cell. A commercial TKK series Pt / C catalyst, model TEC10E30E, was used as the anode catalyst in the proton exchange membrane fuel cell. IV polarization curve tests and cycle stability tests were performed. The experimental steps are as follows:

[0073] a. 30 mg of TaO prepared in Example 1 x The modified commercial platinum-based catalyst material was dispersed in water, isopropanol, and Nafion solution and ultrasonicated for 6 h to obtain a catalyst slurry with a slurry concentration of 2.5 mg / ml;

[0074] b. Spray the above ink to 5cm by ultrasonic spraying equipment 2 As cathode catalyst on the proton exchange membrane; Pt loading is 0.1 mg Pt / cm 2 ;

[0075] c. Spray the TEC10E30E catalyst slurry to 5cm by ultrasonic spraying equipment. 2 On the proton exchange membrane, as the anode catalyst, the Pt loading is 0.05 mg Pt / cm 2 .

[0076] The TaO obtained in Example 1 was treated with reference to the method in Comparative Example 1. x Modified commercial platinum-based catalyst materials for electrochemical performance testing.

[0077] Figure 3 TaO prepared in Example 1 of the present invention x Modified X-ray powder diffraction patterns of commercial platinum-based catalyst materials;

[0078] Figure 4 TaO prepared in Example 1 of the present invention x Scanning transmission electron micrograph of modified commercial platinum-based catalyst material;

[0079] Figure 5 TaO prepared in Example 1 of the present invention x IV polarization curves of the modified commercial Pt-based catalyst material initially and after 30,000 cycles of cycling stability testing.

[0080] Figure 6 TaO prepared in Example 1 of the present invention x CO stripping voltammograms of the modified commercial Pt-based catalyst material initially and after 30,000 cycles of cycling stability testing.

[0081] Depend on Figure 3 and Figure 4 It can be seen that the TaO prepared in Example 1 of the present invention x The commercial platinum-based catalyst material is modified, the particle size of the platinum particles is between 4 and 5 nm, and the tantalum exists in the form of particles, the particle size of the tantalum particles is between 5 and 10 nm, and there is no large-scale agglomeration phenomenon.

[0082] Depend on Figure 5 and Figure 6 The results show that the TaO x The modified commercial platinum-based catalyst material performed well in electrochemical tests. At 94 °C and 65 RH%, the catalyst exhibited a high current density of 0.8 A cm -2 After the cycle stability test, the voltage dropped by only 29mV, and the electrochemical active area decayed by 20%. Compared with the commercial catalyst without tantalum doping in comparative example 1, the activity and stability were significantly improved, and the agglomeration and sintering of platinum in the stability test were effectively alleviated.x The modified commercial platinum-based catalyst material has excellent stability and catalytic activity and has good application prospects.

[0083] Comparative Example 2

[0084] The commercially available Premetek commercial Pt / C catalyst was used as the cathode catalyst of the proton exchange membrane fuel cell, and the commercially available TKK series commercial Pt / C catalyst with model number TEC10E30E was used as the anode catalyst of the proton exchange membrane fuel cell. The electrochemical performance of the catalyst material in Comparative Example 2 was tested by referring to the method in Comparative Example 1.

[0085] Conduct IV polarization curve test and cycle stability test.

[0086] Figure 7 The IV polarization curves of the commercial catalyst in Comparative Example 2 of the present invention are initial and after 30,000 cycles of cyclic stability testing.

[0087] Figure 8 The CO stripping voltammetry curves of the commercial catalyst in Comparative Example 2 of the present invention are the initial and 30,000 cycle stability tests.

[0088] Depend on Figure 7 and Figure 8 The results show that the untreated commercial catalyst is unstable in the electrochemical test, with large attenuation in the polarization curve and CO stripping voltammetry curve.

[0089] Example 2

[0090] a. Disperse 50 mg of Premetek commercial Pt / C catalyst in 35 mL of anhydrous ethanol. After stirring at room temperature for 5 minutes, add 10.02 mg of tantalum ethoxide solution dissolved in anhydrous ethanol. Ultrasonicate the resulting solution for 1 hour and continue stirring at room temperature for 12 hours.

[0091] b. The above solution was evaporated in a rotary vacuum evaporator to obtain a dry powder and transferred to a tube furnace; reduced in a hydrogen / argon gas mixture with a volume fraction of 5%, the heating rate was controlled at 5 ° C / min, the temperature was raised to 600 ° C, the holding time was 1 h, and finally cooled naturally to room temperature. The tube furnace was always maintained at atmospheric pressure; TaO x Modified commercial platinum-based catalyst materials.

[0092] For the TaO obtained in Example 2 xThe commercial platinum-based catalyst material was modified and used as the cathode catalyst of the proton exchange membrane fuel cell. The commercially available TKK series commercial Pt / C catalyst with the model number TEC10E30E was used as the anode catalyst of the proton exchange membrane fuel cell. The TaO obtained in Example 1 was treated with the method in Comparative Example 1. x Modified commercial platinum-based catalyst materials were used for IV polarization curve testing and cycle stability testing.

[0093] Figure 9 TaO prepared in Example 2 of the present invention x Modified X-ray powder diffraction patterns of commercial platinum-based catalyst materials;

[0094] Figure 10 TaO prepared in Example 2 of the present invention x Scanning transmission electron micrograph of modified commercial platinum-based catalyst material;

[0095] Figure 11 TaO prepared in Example 2 of the present invention x IV polarization curves of modified commercial platinum-based catalyst materials initially and after 30,000 cycles of cycling stability testing;

[0096] Figure 12 The TaO prepared in Example 2 of the present invention x CO stripping voltammograms of the modified commercial Pt-based catalyst material initially and after 30,000 cycles of cycling stability testing.

[0097] Depend on Figure 9 and Figure 10 It can be seen that the TaO prepared in Example 2 of the present invention x Modified commercial platinum-based catalyst materials, the particle size of platinum particles is between 3 and 4 nm, tantalum exists in an amorphous form, and there is no large-scale agglomeration of platinum particles;

[0098] Depend on Figure 11 and 12 The results show that the TaO x The modified commercial platinum-based catalyst material performed well in electrochemical tests. At 94 °C and 65 RH%, the catalyst exhibited a high current density of 0.8 A cm -2 After the cycle stability test, the voltage dropped by only 14mV. Compared with the control sample of the commercial catalyst without tantalum, the activity and stability were significantly improved, and the agglomeration and sintering of platinum in the stability test were effectively alleviated. x Modified commercial platinum-based catalyst materials have excellent stability and catalytic activity.

[0099] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A TaO x Modified platinum-based catalysts, including platinum-based catalysts and TaO supported on platinum-based catalysts x ; The TaO x The loading amount of Ta in the modified platinum-based catalyst is 5wt% to 50wt%.

2. TaO according to claim 1 x A modified platinum-based catalyst, characterized in that The platinum-based catalyst comprises a carbon support and platinum supported on the carbon support, and the supported amount of platinum in the platinum-based catalyst is 10 wt% to 50 wt%.

3. TaO according to claim 1 x A modified platinum-based catalyst, characterized in that The TaO x In the modified platinum-based catalyst, the mass ratio of Ta element to platinum element is (0.2-5):

1.

4. TaO according to claim 1 x The preparation method of the modified platinum-based catalyst comprises the following steps: A) dispersing a platinum-based catalyst in a first solvent to obtain a catalyst dispersion; dispersing a tantalum compound in a second solvent to obtain a tantalum source solution; B) adding the tantalum source solution dropwise to the catalyst dispersion to react, and drying the solution after the reaction to obtain an intermediate; C) heat-treating the intermediate in a reducing atmosphere to obtain TaO x Modified platinum-based catalysts.

5. The preparation method according to claim 4, characterized in that The tantalum compound includes one or more of tantalum pentachloride, tantalum nitrate and tantalum pentaethoxide.

6. The preparation method according to claim 4, characterized in that In the step B), the tantalum source solution is added dropwise to the catalyst dispersion, and ultrasonication and stirring are sequentially performed to carry out the reaction; The ultrasonication time is 0.5 to 3 hours, and the stirring time is 6 to 24 hours.

7. The preparation method according to claim 4, characterized in that In the step B), the reaction temperature is 20-30° C., and the reaction time is 6.5-27 hours.

8. The preparation method according to claim 4, characterized in that In the step C), the reducing atmosphere comprises a reducing gas and an inert gas, and the volume fraction of the reducing gas in the reducing atmosphere is 2-10%.

9. The preparation method according to claim 4, characterized in that In the step C), the heat treatment temperature is 300-1000° C., the heat treatment holding time is 0.5-3 hours, and the heat treatment heating rate is 1-20° C. / min.

10. TaO according to any one of claims 1 to 3 x Modified platinum-based catalyst or TaO prepared by the preparation method according to any one of claims 4 to 8 x Application of modified platinum-based catalysts as cathode catalysts in proton exchange membrane fuel cells.

Images