A tubular structure oxide fuel cell cathode catalyst and its preparation method and application

Abstract

A tubular structure oxide fuel cell cathode catalyst and its preparation method and application, relates to an oxide fuel cell cathode catalyst and its preparation method and application. The purpose of the present invention is to solve the problem that the electrocatalytic performance and low oxygen reduction reaction activation energy of existing medium temperature solid oxide fuel cells are poor. A tubular structure oxide fuel cell cathode catalyst has the chemical formula Bi 0.8 Ca 0.2 FeO 3‑δ , a typical single-phase rhombohedral perovskite structure with a space group of R3c and a tubular microstructure. Methods: 1. Impregnation; 2. Calcination. A tubular oxide fuel cell cathode catalyst is used to prepare a symmetrical cell containing a tubular oxide fuel cell cathode catalyst. The method of the present invention is simple, easy to operate, and suitable for industrial production. The present invention can produce a tubular oxide fuel cell cathode catalyst.

Description

Technical Field

[0001] The invention relates to an oxide fuel cell cathode catalyst and a preparation method and application thereof. Background Art

[0002] Solid oxide fuel cells (SOFCs) are an ideal fuel cell, offering not only the high efficiency and environmental friendliness of other fuel cells, but also the following significant advantages: 1) Their all-solid structure eliminates the corrosion and electrolyte loss issues associated with liquid electrolytes, enabling long-life operation. 2) SOFCs operate at temperatures between 800 and 1000°C. Not only do they not require precious metals for electrocatalysts, but they can also directly utilize natural gas, coal gas, and hydrocarbons as fuels, simplifying the fuel cell system. However, their high operating temperatures place stringent demands on the high-temperature chemical compatibility and stability of the cell components. Consequently, the development of key electrode materials for SOFCs operating at medium temperatures between 500 and 700°C has become a major research focus. However, as the operating temperature decreases, the electrochemical activity and output performance of the electrodes decrease dramatically, hindering the application of SOFCs. Therefore, the search for SOFC cathode catalysts with excellent electrochemical activity is necessary. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem of poor electrocatalytic performance and low oxygen reduction reaction activation energy of existing medium-temperature solid oxide fuel cells, and to provide a tubular structure oxide fuel cell cathode catalyst and its preparation method and application.

[0004] A tubular structure oxide fuel cell cathode catalyst has the chemical formula Bi 0.8 Ca 0.2 FeO 3-δ It is a typical single-phase rhombohedral perovskite structure with a space group of R3c, a tubular structure and a specific surface area of ​​88m 2 ·g -1 .

[0005] A method for preparing a tubular structure oxide fuel cell cathode catalyst is to use absorbent cotton as a template to prepare the tubular structure oxide fuel cell cathode catalyst, which is specifically completed by the following steps:

[0006] 1. Impregnation:

[0007] ①, clean and dry the absorbent cotton to obtain the cleaned and dried absorbent cotton;

[0008] ② Dissolve Bi(NO3)3·5H2O, Ca(NO3)2·4H2O, and Fe(NO3)3·9H2O in deionized water to obtain a mixed solution;

[0009] ③. Soak the cleaned and dried absorbent cotton in the mixed solution for a period of time at room temperature, and then dry it to obtain soaked and dried absorbent cotton;

[0010] 2. Calcination:

[0011] The soaked and dried absorbent cotton is placed in a crucible, and then heated to a calcination temperature under an air atmosphere. The crucible is calcined at the calcination temperature for a period of time to obtain a tubular structure oxide fuel cell cathode catalyst.

[0012] A tubular structure oxide fuel cell cathode catalyst is used to prepare a tubular structure oxide fuel cell cathode catalyst symmetrical cell. The specific preparation method is as follows:

[0013] The cathode catalyst of the tubular structure oxide fuel cell is mixed with pine alcohol to obtain a cathode slurry; the cathode slurry is symmetrically brushed on the CGO solid electrolyte, and then placed in a high-temperature furnace for sintering to obtain a symmetrical cell of the tubular structure oxide fuel cell cathode catalyst.

[0014] Beneficial effects of the present invention:

[0015] 1. The present invention uses absorbent cotton as a biomass template to prepare a tubular structure oxide fuel cell cathode catalyst with a larger specific surface area of ​​88m 2 ·g -1 , so that the electrochemical reaction zone is extended to the entire interior of the cathode, increasing the number of reaction active sites and improving the electrochemical performance of the cathode catalyst, thus having electrochemical performance superior to that of powder electrode materials synthesized by the traditional sol-gel method;

[0016] 2. The tubular oxide fuel cell cathode catalyst prepared by the present invention has excellent high-temperature chemical stability and electrocatalytic performance in the temperature range of 500-700°C. The polarization resistance of the symmetrical cell of the tubular oxide fuel cell cathode catalyst prepared using the tubular oxide fuel cell cathode catalyst in air at 700°C is only 0.06Ωcm. -2 , the activation energy is only 128.68 kJmol -1 ;

[0017] 3. The method of the present invention is simple, easy to operate and suitable for industrial production.

[0018] The invention can obtain a cathode catalyst of a tubular structure oxide fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the X-ray diffraction pattern of the tubular structure oxide fuel cell cathode catalyst prepared in Example 1;

[0020] Figure 2 The AC impedance spectrum of the symmetrical cell under 700 ° C air, Figure 1 is the symmetrical cell of the tubular structure oxide fuel cell cathode catalyst prepared in Example 2, and Figure 2 is the Bi prepared by the sol-gel method in Comparative Example 2. 0.8 Ca 0.2 FeO 3-δ Symmetrical cell with cathode catalyst;

[0021] Figure 3 This is an Arrhenius plot of the cathode catalyst of the tubular structure oxide fuel cell prepared in Example 1;

[0022] Figure 4 This is the SEM image of absorbent cotton;

[0023] Figure 5 This is an SEM image of the tubular structure oxide fuel cell cathode catalyst prepared in Example 1. DETAILED DESCRIPTION

[0024] Specific embodiment 1: In this embodiment, a tubular structure oxide fuel cell cathode catalyst has the chemical formula Bi 0.8 Ca 0.2 FeO 3-δ It is a typical single-phase rhombohedral perovskite structure with a space group of R3c, a tubular structure and a specific surface area of ​​88m 2 ·g -1 .

[0025] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that a tubular structure oxide fuel cell cathode catalyst symmetrical cell prepared by a tubular structure oxide fuel cell cathode catalyst has a polarization resistance of 0.06Ωcm in air at 700℃. -2 , the activation energy is 128.68 kJmol -1 The other steps are the same as those in the first embodiment.

[0026] Specific embodiment three: This embodiment is a method for preparing a tubular structure oxide fuel cell cathode catalyst, which uses absorbent cotton as a template to prepare the tubular structure oxide fuel cell cathode catalyst, specifically completed in the following steps:

[0027] 1. Impregnation:

[0028] ①, clean and dry the absorbent cotton to obtain the cleaned and dried absorbent cotton;

[0029] ② Dissolve Bi(NO3)3·5H2O, Ca(NO3)2·4H2O, and Fe(NO3)3·9H2O in deionized water to obtain a mixed solution;

[0030] ③. Soak the cleaned and dried absorbent cotton in the mixed solution for a period of time at room temperature, and then dry it to obtain soaked and dried absorbent cotton;

[0031] 2. Calcination:

[0032] The soaked and dried absorbent cotton is placed in a crucible, and then heated to a calcination temperature under an air atmosphere. The crucible is calcined at the calcination temperature for a period of time to obtain a tubular structure oxide fuel cell cathode catalyst.

[0033] Specific Embodiment 4: This embodiment differs from Specific Embodiments 1 to 3 in that: in step 1 (1), the absorbent cotton is washed 3 to 5 times with deionized water and then dried at 60°C to obtain washed and dried absorbent cotton; in step 1 (3), the washed and dried absorbent cotton is soaked in the mixed solution at room temperature for 6 hours and then dried at 60°C for 12 hours. The other steps are the same as Specific Embodiments 1 to 3.

[0034] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the mass ratio of Bi(NO3)3·5H2O to deionized water in step 1 (2) is 1.94 g:100 mL; the mass ratio of Ca(NO3)2·4H2O to deionized water in step 1 (2) is 0.24 g:100 mL; and the mass ratio of Fe(NO3)3·9H2O to deionized water in step 1 (2) is 2.02 g:100 mL. The other steps are the same as those in specific embodiments 1 to 4.

[0035] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the volume ratio of the absorbent cotton in step 1 (3) to the deionized water in step 1 (2) is 2 g:100 mL. The other steps are the same as those in specific embodiments 1 to 5.

[0036] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the heating rate in step 2 is 1°C / min; the calcination temperature in step 2 is 800°C; and the calcination time is 2 hours. The other steps are the same as specific embodiments 1 to 6.

[0037] Specific embodiment eight: This embodiment is a tubular structure oxide fuel cell cathode catalyst for preparing a tubular structure oxide fuel cell cathode catalyst symmetrical cell, the specific preparation method is as follows:

[0038] The cathode catalyst of the tubular structure oxide fuel cell is mixed with pine alcohol to obtain a cathode slurry; the cathode slurry is symmetrically brushed on the CGO solid electrolyte, and then placed in a high-temperature furnace for sintering to obtain a symmetrical cell of the tubular structure oxide fuel cell cathode catalyst.

[0039] Specific Embodiment 9: This embodiment differs from Specific Embodiments 1 to 8 in that the mass ratio of the tubular oxide fuel cell cathode catalyst to the volume of terpineol is 0.1 g:(0.05 mL to 0.1 mL); and the sintering process is: first sintering at 350°C to 400°C for 1 to 2 hours, then sintering at 700°C to 800°C for 15 to 30 minutes. Other steps are the same as Specific Embodiments 1 to 8.

[0040] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the sintering process is: first sintering at 400°C for 2 hours, then sintering at 750°C for 15 minutes. The other steps are the same as specific embodiments 1 to 9.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0042] Example 1: A method for preparing a tubular structure oxide fuel cell cathode catalyst using absorbent cotton as a template is specifically completed by the following steps:

[0043] 1. Impregnation:

[0044] ①, wash the absorbent cotton with deionized water three times, and then dry it at 60℃ for 12h to obtain the washed and dried absorbent cotton;

[0045] ② Dissolve 1.94 g Bi(NO3)3·5H2O, 0.24 g Ca(NO3)2·4H2O, and 2.02 g Fe(NO3)3·9H2O in 100 mL of deionized water to obtain a mixed solution;

[0046] ③ Soak 2 g of cleaned and dried absorbent cotton in the above mixed solution at room temperature for 6 h, and then dry at 60°C for 12 h to obtain soaked and dried absorbent cotton;

[0047] 2. Calcination:

[0048] The soaked and dried absorbent cotton was placed in a crucible, and then heated to 800°C at a heating rate of 1°C / min in an air atmosphere, and calcined at 800°C for 2 hours to obtain a tubular structure oxide fuel cell cathode catalyst.

[0049] Figure 1 This is the X-ray diffraction pattern of the tubular structure oxide fuel cell cathode catalyst prepared in Example 1;

[0050] from Figure 1 It can be seen that the cathode catalyst of the tubular structure oxide fuel cell prepared in Example 1 is a typical single-phase rhombohedral perovskite structure with a space group of R3c.

[0051] Example 2: A symmetrical cell of a tubular structure oxide fuel cell cathode catalyst was prepared using the tubular structure oxide fuel cell cathode catalyst prepared in Example 1. The specific preparation method is as follows:

[0052] 0.1 g of the tubular structure oxide fuel cell cathode catalyst prepared in Example 1 was mixed with 0.05 mL of pine oil to obtain a cathode slurry; the cathode slurry was symmetrically brushed on a CGO solid electrolyte (purchased from Ningbo Suofuren Energy Technology Co., Ltd.), and then placed in a high-temperature furnace, first sintered at 400°C for 2 hours, and then sintered at 750°C for 15 minutes to obtain a symmetrical cell of tubular structure oxide fuel cell cathode catalyst.

[0053] Comparative Example 2: Bi prepared by sol-gel method 0.8 Ca 0.2 FeO 3-δ The cathode catalyst symmetrical cell is prepared as follows:

[0054] 0.1 g of Bi prepared by sol-gel method was 0.8 Ca 0.2 FeO 3-δ The cathode catalyst was mixed with 0.05 mL of terpineol to obtain a cathode slurry. The cathode slurry was symmetrically brushed on a CGO solid electrolyte (purchased from Ningbo Suofer Energy Technology Co., Ltd.), and then placed in a high-temperature furnace and sintered at 900 ° C for 4 h to obtain Bi prepared by the sol-gel method. 0.8 Ca 0.2 FeO 3-δ Symmetrical cell with cathode catalyst.

[0055] Figure 2 The AC impedance spectrum of the symmetrical cell under 700 ° C air, Figure 1 is the symmetrical cell of the tubular structure oxide fuel cell cathode catalyst prepared in Example 2, and Figure 2 is the Bi prepared by the sol-gel method in Comparative Example 2. 0.8 Ca 0.2 FeO 3-δ Symmetrical cell with cathode catalyst;

[0056] from Figure 2 It can be seen that the polarization resistance of the symmetrical cell of the cathode catalyst of the tubular structure oxide fuel cell prepared in Example 2 is 0.06Ωcm -2 This result is compared with the Bi prepared by sol-gel method in Example 2. 0.8 Ca 0.2 FeO 3-δ Half of the cathode catalyst symmetric cell (0.12Ωcm at the same test temperature) -2 ),See Figure 2 ; This shows that the Bi obtained by biomass template synthesis technology0.8 Ca 0.2 FeO 3-δ Tubular structured oxide fuel cell cathode catalysts can improve the electrochemical performance of the cathode.

[0057] Figure 3 This is an Arrhenius plot of the cathode catalyst of the tubular structure oxide fuel cell prepared in Example 1;

[0058] from Figure 3 It can be seen that the activation energy of the prepared tubular structure oxide fuel cell cathode catalyst is 128.68 kJ mol -1 .

[0059] Figure 4 This is the SEM image of absorbent cotton;

[0060] Figure 5 This is an SEM image of the tubular structure oxide fuel cell cathode catalyst prepared in Example 1.

[0061] from Figures 4 and 5 It can be seen that the prepared oxide fuel cell cathode catalyst has a tubular structure, the surface of the sample is smooth and the crystallinity is good.

Claims

1. A method for preparing a cathode catalyst for a tubular structure oxide fuel cell, characterized in that This method uses cotton wool as a template to prepare a tubular structure oxide fuel cell cathode catalyst with a chemical formula of Bi 0.8 Ca 0.2 FeO 3-δ It is a typical single-phase rhombohedral perovskite structure with a space group of R3c, a tubular structure and a specific surface area of ​​88m 2 ·g -1 ; The preparation method is specifically completed according to the following steps:

1. Impregnation: ①, clean and dry the absorbent cotton to obtain the cleaned and dried absorbent cotton; ② Dissolve Bi(NO3)3·5H2O, Ca(NO3)2·4H2O, and Fe(NO3)3·9H2O in deionized water to obtain a mixed solution; The mass ratio of Bi(NO3)3·5H2O to deionized water described in step 1② is 1.94g:100mL; The mass ratio of Ca(NO3)2·4H2O to deionized water described in step 1② is 0.24g:100mL; The mass ratio of Fe(NO3)3·9H2O to deionized water described in step 1② is 2.02g:100mL; ③. Soak the cleaned and dried absorbent cotton in the mixed solution for a period of time at room temperature, and then dry it to obtain soaked and dried absorbent cotton; The volume ratio of the absorbent cotton in step 1 (3) to the deionized water in step 1 (2) is 2 g:100 mL; 2. Calcination: The soaked and dried absorbent cotton is placed in a crucible, and then heated to a calcination temperature in an air atmosphere, and calcined at the calcination temperature for a period of time to obtain a tubular structure oxide fuel cell cathode catalyst; The heating rate in step 2 is 1° C. / min; the calcination temperature in step 2 is 800° C.; and the calcination time is 2 h.

2. The method for preparing a cathode catalyst for a tubular structure oxide fuel cell according to claim 1, characterized in that In step 1①, the cotton wool was washed with deionized water for 3 to 5 times, and then dried at 60°C to obtain washed and dried cotton wool; in step 1③, the washed and dried cotton wool was soaked in the mixed solution at room temperature for 6 hours, and then dried at 60°C for 12 hours.

3. Use of a tubular structure oxide fuel cell cathode catalyst prepared by the preparation method according to any one of claims 1 to 2, characterized in that A tubular structure oxide fuel cell cathode catalyst is used to prepare a tubular structure oxide fuel cell cathode catalyst symmetrical cell, wherein the polarization resistance of the symmetrical cell is 0.06 Ωcm in air at 700°C. -2 , the activation energy is 128.68 kJmol -1 ; The preparation method is as follows: The cathode catalyst of the tubular structure oxide fuel cell is mixed with pine alcohol to obtain a cathode slurry; the cathode slurry is symmetrically brushed on the CGO solid electrolyte, and then placed in a high-temperature furnace for sintering to obtain a symmetrical cell of the tubular structure oxide fuel cell cathode catalyst.

4. The use of a tubular structure oxide fuel cell cathode catalyst according to claim 3, characterized in that The mass ratio of the tubular structure oxide fuel cell cathode catalyst to the volume ratio of terpineol is 0.1g:(0.05mL~0.1mL); the sintering process is: first sintering at 350℃~400℃ for 1h~2h, and then sintering at 700℃~800℃ for 15min~30min.

5. The use of a tubular structure oxide fuel cell cathode catalyst according to claim 4, characterized in that The sintering process is as follows: first sintering at 400°C for 2 hours, and then sintering at 750°C for 15 minutes.

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