Nickel-iron alloy precipitation type perovskite catalytic material with high ammonia decomposition activity and solid oxide fuel cell performance

Abstract

The invention discloses a nickel-iron alloy precipitation type perovskite catalytic material with excellent ammonia decomposition activity and solid oxide fuel cell performance as well as a preparation method and an application of the nickel-iron alloy precipitation type perovskite catalytic material. The general formula of the catalytic material is La < 0.7 > Sr < 0.2 > Fe < 1-x > Ni < x > O < 3-delta > (0 lt, x is smaller than or equal to 0.3), uniform precipitation of Ni-Fe nano-alloy particles is promoted under a high-temperature condition through B-site nickel doping and A-site defect regulation, ammonia decomposition activity is remarkably improved, and electron-ion mixed conductivity of the material is enhanced. A stable three-dimensional polymer network structure is constructed through batch feeding and a citric acid-sol-gel method, the ammonia decomposition rate of the obtained catalytic material at 600-800 DEG C is close to the equilibrium conversion rate, the power density of a fuel cell is remarkably improved, and the problem that a traditional Ni-based anode is prone to sintering and agglomeration at high temperature is effectively solved. The material is compatible with a plurality of electrolyte systems such as YSZ, GDC and SDC, and is suitable for application scenarios such as a plurality of fuel cell electrodes.

Description

Technical Field

[0001] The present invention belongs to the fields of catalyst preparation and application of electrode materials for ammonia solid oxide fuel cells, and particularly relates to a nickel-iron alloy precipitated perovskite catalytic material with both high ammonia decomposition activity and solid oxide fuel cell performance. Background Art

[0002] At present, the energy shortage and climate deterioration worldwide have attracted strong attention and stimulated the research and development of carbon-free energy. Among various carbon-free energies, hydrogen energy is one of the most ideal clean fuels. However, hydrogen faces major challenges in terms of safety and storage and transportation. Among all current hydrogen storage materials, ammonia has the highest hydrogen content, and with its highly mature transportation and storage, ammonia is an excellent hydrogen energy carrier, providing more choices for the development of future green energy. Currently, ammonia-based fuels can be applied to direct combustion and fuel cell technologies. However, problems such as high auto-ignition temperature, narrow combustion range, low combustion speed, and large NO x emissions hinder the popularization of direct combustion technology on land. Only when mixed with hydrogen can these problems be successfully solved. However, due to the immature storage and transportation technology and low safety of hydrogen, there are a large number of potential safety hazards in the application of ammonia direct combustion technology on land. Therefore, ammonia fuel cell (NH3-SOFC) technology with clean emissions, including indirect fuel cells and direct fuel cells, is considered promising for establishing an efficient ammonia energy system. Among them, direct ammonia fuel cell technology can break the Carnot cycle, and the heat released by the electrochemical reaction is directly provided for the ammonia decomposition reaction to achieve efficient heat utilization.

[0003] In direct NH3-SOFCs, ammonia can be directly fed into SOFCs without pretreatment or an external reactor. Its anode, that is, the fuel electrode, functions to transfer the electrons released by the electrochemical oxidation reaction of the fuel gas to the external circuit and discharge the gas at the same time. The performance requirements of the anode are similar to those of the cathode. However, since it has to work in a reducing atmosphere, the anode material of SOFCs should have high electronic and ionic conductivity, good stability, excellent catalytic activity, and thermal expansion and compatibility matching the battery materials. Currently, it is found that noble metals (Pt, Au) and transition metals (Fe, Co, Ni), etc. have good catalytic effects. However, there are many problems in the application of metal materials. For example, the Pt electrode is prone to volatilization and peeling during the high-temperature operation of the battery, its reserves are small and the price is high; the Fe electrode is easily oxidized to form Fe2O3, resulting in electrode deactivation; the Co electrode is stable but has a high price and high toxicity; the Ni electrode has good catalytic activity and low price, but it has a large thermal expansion coefficient and is prone to sintering and caking at high temperatures, and is not suitable for use as an anode material alone. Therefore, there is an urgent need to develop a stable anode material for SOFCs. Summary of the Invention

[0004] The present invention aims to provide a preparation method of a perovskite catalyst capable of realizing uniform precipitation and distribution of metal nanoparticles on the surface of a material and its application in the anode catalytic material of an ammonia solid oxide fuel cell.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A preparation method of a nickel-iron alloy-precipitated perovskite catalytic material with both high ammonia decomposition activity and solid oxide fuel cell performance: Using lanthanum nitrate hexahydrate, strontium nitrate, nickel nitrate hexahydrate, and iron nitrate nonahydrate as precursors, and citric acid, ethylene glycol, and EDTA as complexing agents, setting a certain temperature and pH, mixing evenly in the liquid phase to prepare a transparent polymer resin precursor, and obtaining a lanthanum strontium iron nickel perovskite electrode catalytic material with high ammonia decomposition catalytic activity after aging, drying, and calcination.

[0006] The above preparation method specifically includes the following steps: (1) Add La(NO3)3·6H2O, Sr(NO3)2, Fe(NO3)3·9H2O, and Ni(NO3)2·6H2O to 100 mL of deionized water and stir for 15 min; (2) Add citric acid to the solution obtained in step (1), add ethylene glycol after the citric acid is completely dissolved, and then add EDTA. After the EDTA is completely dissolved, place it in a constant temperature water bath and stir and evaporate for 5 h to obtain a transparent polymer resin precursor; (3) Dry the transparent polymer resin precursor. After drying, the volume expands to obtain a complete black porous dry gel precursor with a loose and porous interior. The ligand complexes that have lost fluidity are filled between the gel networks. Further, after grinding, it is calcined to obtain the catalytic material La 0.7 Sr 0.2 Fe 1-x Ni x O 3-δ , 0 < x ≤ 0.3.

[0007] Further, the molar ratio of La(NO3)3·6H2O:Sr(NO3)2, Fe(NO3)3·9H2O:Ni(NO3)2·6H2O is 7:2:10 - x:x, x = 0 - 5; the molar ratio of citric acid, EDTA to the total metal ions is 3:3:2; the mass ratio of ethylene glycol to citric acid is 2:3.

[0008] Further, the temperature of the constant temperature water bath in step (2) is 70 - 90 °C, and the time is 4 - 8 h.

[0009] Further, in step (3), the drying temperature is 150 - 180 °C and the time is 12 - 24 h; the calcination temperature is 800 - 1000 °C and the time is 3 - 8 h.

[0010] The nickel-iron alloy precipitated perovskite catalytic material obtained by the above preparation method can be applied to the anode catalytic material of an ammonia solid oxide fuel cell.

[0011] Further, the specific application method is as follows: Grind the catalytic material La 0.7 Sr 0.2 Fe 1-x Ni x O 3-δ and the electrolyte powder in a mass ratio of 3:2 to obtain the anode composite electrode powder, then add and drop terpineol containing ethyl cellulose as a binder and a dispersant, and grind the anode composite electrode powder for 1 h to prepare the electrode paste. The electrolyte powder is gadolinium-doped ceria, yttrium-doped zirconia, cerium-doped samarium oxide, or strontium and magnesium-doped lanthanum gallate; the mass fraction of ethyl cellulose in the terpineol containing ethyl cellulose is 2% - 4%, and the dosage of the terpineol containing ethyl cellulose is 1 - 2 mL.

[0012] Print the obtained electrode paste on one side of a yttria-stabilized zirconia electrolyte-supported cell by screen printing, dry it, and then place it in a muffle furnace for calcination to obtain the single-cell anode material. The calcination temperature is 800 - 1200 °C and the calcination time is 2 - 5 h.

[0013] In summary, a nickel-doped La with A-site defects developed by the present invention 0.7 Sr 0.2 Fe 1-x Ni x O 3-δ (LSFN) perovskite can achieve the uniform precipitation of Ni-Fe alloy on the material surface, solving the problem that Ni is prone to sintering at high temperatures; the introduction of A-site defects can further promote the precipitation of Ni-Fe alloy nanoparticles; the doping of nickel can further increase the oxygen vacancy concentration of the material, improving the ionic conductivity of the material; the doping of strontium can increase the content of high-valent metal ions such as Fe 4+ and Ni 3+ , increasing the opportunity for charge conduction and making the material exhibit higher electronic conductivity. In summary, the LSFN perovskite material described in the present invention is an ideal anode catalytic material for NH3-SOFC.

[0014] The technical solution of the present invention has the following advantages: (1) The preparation conditions of the present invention are simple. By doping nickel at the B-site and regulating the A-site defects, the precipitation of nickel-iron nanoalloy particles is promoted. The prepared LSFN perovskite catalyst has high ammonia decomposition catalytic ability, enabling the ammonia decomposition rate to reach the equilibrium conversion rate at 600 - 800 °C, effectively improving the electrochemical output performance of ammonia solid oxide fuel cells.

[0015] (2) The introduction of nickel element at the B-site and the construction of A-site defects can both effectively promote the precipitation of metal nanoparticles, realize the uniform distribution of metal nanoparticles on the material surface, have strong anti-sintering ability, and excellent oxygen vacancy regulation, effectively solving the problems of easy agglomeration and sintering of nickel at high temperatures, poor ammonia decomposition, and poor performance of ammonia solid oxide fuel cells.

[0016] (3) The introduction of strontium at the A-site and nickel at the B-site effectively improves the conductivity of the material, has excellent oxygen vacancy regulation, and is compatible with electrolytes such as YSZ, GDC, and SDC. It can not only be used as the anode of NH3 - SOFC, but also be applicable to ammonia decomposition for hydrogen production, industrial tail gas treatment, and other high-temperature fuel cell systems.

[0017] (4) The entire process of the present invention is simple and easy to control, the production process is green and environmentally friendly, with low energy consumption, high yield, and low cost, meeting the actual production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the X-ray powder diffraction pattern of the perovskite catalytic materials obtained in Example 5 and Comparative Example 3.

[0019] Figure 2 It is the SEM micrograph of Example 5 after being reduced in 50% H2 / Ar gas at 800 °C for 8 h.

[0020] Figure 3 It is the test result of ammonia decomposition performance of Example 5 and traditional NiO anode material.

[0021] Figure 4 It is the test result of electrochemical output performance of Example 5 and traditional NiO anode material. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0023] Example 1 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, 4.545 g of Fe(NO3)3·9H2O, and 0.3635 g of Ni(NO3)2·6H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the above solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol, then add 10.4111 g of EDTA. At the same time, dropwise add concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the obtained solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After drying it thoroughly in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with a porous and loose interior. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine it for 5 h to obtain a dark gray LSFN powder. Through thorough grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 Fe 0.9 Ni 0.1 O 3-δ 。

[0024] Example 2 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, 4.2925 g of Fe(NO3)3·9H2O, and 0.5452 g of Ni(NO3)2·6H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol, then add 10.4111 g of EDTA. At the same time, dropwise add concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the obtained solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After drying it thoroughly in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with a porous and loose interior. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine it for 5 h to obtain a dark gray LSFN powder. Through thorough grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 Fe 0.85 Ni 0.15 O 3-δ 。

[0025] Example 3 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, 4.04 g of Fe(NO3)3·9H2O, and 0.727 g of Ni(NO3)2·6H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol, then add 10.4111 g of EDTA. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the resulting solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After fully drying it in a constant temperature oven at 150 °C for 12 h, it expands in volume to obtain a complete black three-dimensional polymer framework with a porous and loose interior. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a uniform black powder. Place the powder in a muffle furnace at 1000 °C and calcine for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 Fe 0.8 Ni 0.2 O 3-δ is obtained.

[0026] Example 4 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, 3.7875 g of Fe(NO3)3·9H2O, and 0.909 g of Ni(NO3)2·6H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol, then add 10.4111 g of EDTA. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the resulting solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After fully drying it in a constant temperature oven at 150 °C for 12 h, it expands in volume to obtain a complete black three-dimensional polymer framework with a porous and loose interior. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a uniform black powder. Place the powder in a muffle furnace at 1000 °C and calcine for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 Fe 0.75 Ni 0.25 O 3-δ is obtained.

[0027] Example 5 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, 3.535 g of Fe(NO3)3·9H2O, and 1.0905 g of Ni(NO3)2·6H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol, and then add 10.4111 g of EDTA. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the obtained solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After it is fully dried in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with loose pores inside. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 Fe 0.7 Ni 0.3 O 3-δ 。

[0028] Comparative Example 1 Weigh 5.4126 g of La(NO3)3·6H2O and 5.05 g of Fe(NO3)3·9H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid according to the stoichiometric ratio and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol according to the mass ratio, and then add 10.4111 g of EDTA according to the stoichiometric ratio. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the obtained solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymer resin precursor. After it is fully dried in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with loose pores inside. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material LaFeO3 is obtained.

[0029] Comparative Example 2 Weigh 3.7888 g of La(NO3)3·6H2O, 0.7936 g of Sr(NO3)2, and 5.05 g of Fe(NO3)3·9H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol. Then add 10.4111 g of EDTA according to the stoichiometric ratio. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the resulting solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymeric resin precursor. After drying it thoroughly in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with loose pores inside. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine it for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material La 0.7 Sr 0.3 FeO 3-δ is obtained.

[0030] Comparative Example 3 Weigh 3.7888 g of La(NO3)3·6H2O, 0.5291 g of Sr(NO3)2, and 5.05 g of Fe(NO3)3·9H2O and place them in a 250 ml beaker. Add 100 ml of deionized water and stir for 15 min. Weigh 6.8443 g of citric acid and add it to the solution. After the citric acid is completely dissolved, add 4.5629 g of ethylene glycol. Then add 10.4111 g of EDTA. At the same time, drop in concentrated ammonia water (28%) to maintain the pH of the solution at 6. After the EDTA is completely dissolved, stir and evaporate the resulting solution in a constant temperature water bath at 80 °C for 5 h to undergo polymerization to obtain a dark green to dark brown transparent polymeric resin precursor. After drying it thoroughly in a constant temperature oven at 150 °C for 12 h, its volume expands to obtain a complete black three-dimensional polymer framework with loose pores inside. Grind the obtained three-dimensional polymer framework in an agate mortar for 20 min to obtain a black uniform powder. Place the powder in a muffle furnace at 1000 °C and calcine it for 5 h to obtain a dark gray LSFN powder. Through sufficient grinding using an agate mortar, the catalytic material La 0.7 Sr 0.2 FeO 3-δ is obtained.

[0031] Application Example 1 Take 0.6 g of the above-mentioned anode powder and 0.4 g of gadolinium-doped ceria (GDC) powder, and grind them thoroughly in an agate mortar to obtain the anode composite electrode powder. Then, add 1.5 mL of a terpineol organic mixture containing 2% ethyl cellulose to the agate mortar as a binder and dispersant, and grind the electrode powder thoroughly for 1 h to prepare the electrode slurry. Print the electrode slurry on one side of a yttria-stabilized zirconia (YSZ) electrolyte-supported cell by screen printing, dry it, and then place it in a muffle furnace and calcine it at 800 °C for 2 h to ensure full contact between the anode material and the cell. The cathode material is a composite electrode powder of lanthanum strontium cobalt iron (LSCF) and GDC (mass ratio 4:6). After the cell is assembled, heat it to 800 °C and reduce it in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test can be carried out.

[0032] Application Example 2 Take 0.6 g of the above-mentioned anode powder and 0.4 g of gadolinium-doped ceria (GDC) powder, and grind them thoroughly in an agate mortar to obtain the anode composite electrode powder. Then, add 1.5 mL of a terpineol organic mixture containing 4% ethyl cellulose to the agate mortar as a binder and dispersant, and grind the electrode powder thoroughly for 1 h to prepare the electrode slurry. Print the electrode slurry on one side of a yttria-stabilized zirconia (YSZ) electrolyte-supported cell by screen printing, dry it, and then place it in a muffle furnace and calcine it at 800 °C for 2 h to ensure full contact between the anode material and the cell. The cathode material is a composite electrode powder of lanthanum strontium cobalt iron (LSCF) and GDC (mass ratio 4:6). After the cell is assembled, heat it to 800 °C and reduce it in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test can be carried out.

[0033] Application Example 3 Take 0.6 g of the above-mentioned anode powder and 0.4 g of gadolinium-doped ceria (GDC) powder, and grind them thoroughly in an agate mortar to obtain the anode composite electrode powder. Then, add 1.5 mL of a terpineol organic mixture containing 4% ethyl cellulose to the agate mortar as a binder and dispersant, and grind the electrode powder thoroughly for 1 h to prepare the electrode slurry. Print the electrode slurry on one side of a yttria-stabilized zirconia (YSZ) electrolyte-supported cell by screen printing, dry it, and then place it in a muffle furnace and calcine it at 900 °C for 2 h to ensure full contact between the anode material and the cell. The cathode material is a composite electrode powder of lanthanum strontium cobalt iron (LSCF) and GDC (mass ratio 4:6). After the cell is assembled, heat it to 800 °C and reduce it in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test can be carried out.

[0034] Application Example 4 0.6 g of the above anode powder and 0.4 g of gadolinium-doped cerium oxide (GDC) powder were fully ground in an agate mortar to obtain an anode composite electrode powder, and then 1.5 mL of a pine alcohol organic mixture containing 4% ethyl cellulose was added to the agate mortar as a binder and dispersant, and the electrode powder was fully ground for 1 h to obtain an electrode slurry. The electrode slurry was screen-printed on one side of the yttria-stabilized zirconia (YSZ) electrolyte-supported cell, dried, and placed in a muffle furnace for calcination at 1000 ° C for 2 h to make the anode material fully contact the cell. The cathode material was a lanthanum strontium cobalt iron (LSCF) and GDC composite electrode powder (mass ratio of 4:6). After the battery was built, the temperature was raised to 800 ° C and reduced in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test was carried out.

[0035] Application Example 5 0.6 g of the above anode powder and 0.4 g of gadolinium-doped cerium oxide (GDC) powder were fully ground in an agate mortar to obtain an anode composite electrode powder, and then 1.5 mL of a pine alcohol organic mixture containing 4% ethyl cellulose was added to the agate mortar as a binder and dispersant, and the electrode powder was fully ground for 1 h to obtain an electrode slurry. The electrode slurry was screen-printed on one side of the yttria-stabilized zirconia (YSZ) electrolyte-supported cell, dried, and placed in a muffle furnace for calcination at 1100 ° C for 2 h to make the anode material fully contact the cell. The cathode material was a lanthanum strontium cobalt iron (LSCF) and GDC composite electrode powder (mass ratio of 4:6). After the battery was built, the temperature was raised to 800 ° C and reduced in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test was carried out.

[0036] Application Example 6 0.6 g of the above anode powder and 0.4 g of gadolinium-doped cerium oxide (GDC) powder were fully ground in an agate mortar to obtain an anode composite electrode powder, and then 1.5 mL of a pine alcohol organic mixture containing 4% ethyl cellulose was added to the agate mortar as a binder and dispersant, and the electrode powder was fully ground for 1 h to obtain an electrode slurry. The electrode slurry was screen-printed on one side of a yttria-stabilized zirconia (YSZ) electrolyte-supported cell, dried, and calcined at 1200 ° C in a muffle furnace for 2 h to make the anode material fully contact the cell. The cathode material was a lanthanum strontium cobalt iron (LSCF) and GDC composite electrode powder (mass ratio of 4:6). After the battery was built, the temperature was raised to 800 ° C and reduced in 50% H2 / Ar gas for 8 h, and then the electrochemical performance test was carried out.

[0037] Table 1 is a comparison of the output power density of ammonia solid oxide fuel cells prepared by the catalysts of the examples and comparative examples at 800°C (corresponding to the preparation conditions of Application Example 4)

[0038] Comparing Comparative Examples 1 and 2, the introduction of strontium element at the A-site can effectively improve the output performance of the material; the introduction of A-site defects can effectively promote the precipitation of B-site metal nanoparticles, improve the catalytic performance of the catalytic material, and thus increase the battery output power; the introduction of Ni element at the B-site can effectively further increase the battery output power. With the increase of Ni content, the battery output power is further increased, indicating that the introduction of more easily reducible Ni element can also further promote the precipitation of metal nanoparticles, thereby further enhancing the battery output power.

[0039] Figure 1 The X-ray powder diffraction patterns of the perovskite catalytic materials obtained in Comparative Example 3 and Example 5 are shown. It can be seen that the detected characteristic peaks are consistent with the standard cards, indicating that the LSFN perovskite has been successfully prepared, and Sr and Ni elements have been successfully doped into the lanthanum ferrite perovskite phase.

[0040] Figure 2 The SEM micrograph of Example 5 after reduction in 50% H2 / Ar gas at 800 °C for 8 h is shown. It can be seen that a large number of nano-alloy particles are evenly distributed on the surface of the material.

[0041] Figure 3 The ammonia decomposition performance test results of Example 5 and the traditional NiO anode material are shown. The results show that the ammonia decomposition performance of the LSFN perovskite anode material prepared by the present invention is significantly higher than that of the traditional NiO anode. When the working temperature reaches 700 °C and above, the ammonia decomposition rate is close to 100%, indicating that LSFN has excellent ammonia decomposition performance.

[0042] Figure 4 The electrochemical output performance test results of Example 5 and the traditional NiO anode material are shown. The same specification of YSZ electrolyte support sheets are used for the battery chips, the same dispersant of 4% ethyl cellulose in terpineol is used, the calcination temperature of the anode material is 1000 °C for 2 h, and the cathode material is a composite electrode powder of lanthanum strontium cobalt iron (LSCF) and GDC (mass ratio 4:6), with the calcination temperature and time of 1100 °C and 2 h respectively. The electrochemical output performance test results show that the LSFN perovskite material prepared by the present invention has excellent electrochemical output performance. Especially at the working temperatures of 750 °C and 800 °C, its output performance is more than twice that of the traditional NiO anode, reaching 159.84123 mW·cm -2 and 349.78472 mW·cm -2 .

[0043] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A method for preparing a nickel-iron alloy precipitation-type perovskite catalyst material having both high ammonia decomposition activity and solid oxide fuel cell performance, characterized in that: Lanthanum nitrate hexahydrate, strontium nitrate, nickel nitrate hexahydrate and ferric nitrate nonahydrate are used as precursors, citric acid, ethylene glycol and EDTA are used as complexing agents, a certain temperature and pH value are set, and the mixture is evenly mixed in the liquid phase to prepare a transparent polymer resin precursor. After aging, drying and calcination, a lanthanum strontium iron nickel perovskite electrode catalyst material with high efficiency in ammonia decomposition catalysis is obtained.

2. The preparation method according to claim 1, characterized in that: The specific steps include: (1) Add La(NO3)3·6H2O, Sr(NO3)2, Fe(NO3)3·9H2O, and Ni(NO3)2·6H2O to 100 mL of deionized water and stir for 15 min; (2) adding citric acid to the solution obtained in step (1), adding ethylene glycol after the citric acid is completely dissolved, and then adding EDTA, and placing the mixture in a constant temperature water bath and stirring and evaporating for 5 hours after the EDTA is completely dissolved to obtain a transparent polymer resin precursor; (3) Drying, grinding and calcining the transparent polymer resin precursor to obtain the catalytic material La 0.7 Sr 0.2 Fe 1-x Ni x O 3-δ , 0 < x≤ 0.

3.

3. The preparation method according to claim 2, characterized in that: The molar ratio of La(NO3)3·6H2O:Sr(NO3)2, Fe(NO3)3·9H2O:Ni(NO3)2·6H2O is 7:2:10-x:x, x=0-5; the molar ratio of citric acid, EDTA and total metal ions is 3:3:2; the mass ratio of ethylene glycol to citric acid is 2:

3.

4. The preparation method according to claim 2, characterized in that: The temperature of the constant temperature water bath in step (2) is 70-90°C and the time is 4-8h.

5. The preparation method according to claim 2, characterized in that: The drying temperature in step (3) is 150-180°C and the time is 12-24 hours; the calcination temperature is 800-1000°C and the time is 3-8 hours.

6. Use of the nickel-iron alloy precipitation-type perovskite catalyst material obtained by the preparation method according to any one of claims 1 to 5 in ammonia solid oxide fuel cell anode catalyst material.

7. The use according to claim 6, characterized in that: The catalytic material La 0.7 Sr 0.2 Fe 1-x Ni x O 3-δ The anode composite electrode powder was obtained by grinding with the electrolyte powder in a mass ratio of 3:2, and then pineneol containing ethyl cellulose was added as a binder and dispersant, and the anode composite electrode powder was ground for 1 h to obtain an electrode slurry. The electrolyte powder was gadolinium-doped cerium oxide, yttrium-doped zirconium oxide, cerium-doped samarium oxide, and strontium magnesium-doped lanthanum gallate.

8. The use according to claim 7, characterized in that: The mass fraction of ethyl cellulose in the terpineol containing ethyl cellulose is 2%-4%, and the amount of the terpineol containing ethyl cellulose is 1-2 mL.

9. The use according to claim 7, characterized in that: The electrode slurry is printed on one side of the yttria-stabilized zirconia electrolyte supporting cell sheet by screen printing, and after drying, it is placed in a muffle furnace for calcination to obtain a single cell anode material.

10. The use according to claim 9, characterized in that: The calcination temperature is 800-1200°C and the calcination time is 2-5h.

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