A methane-carbon dioxide dry reforming catalyst and solid oxide fuel cell and method of preparation

Abstract

The application discloses a methane-carbon dioxide dry reforming catalyst and a solid oxide fuel cell and a preparation method, and relates to the field of fuel cells. 0.75 Sr 0.25 ) 1‑x / 2 Li x Cr 0.5 Fe 0.4 Ni 0.1 O 3‑δ , wherein 0

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a methane-carbon dioxide dry reforming catalyst, a solid oxide fuel cell, and a method for its preparation. Background Technology

[0002] Solid oxide fuel cells (SOCs) are a clean and efficient energy system that can directly convert the chemical energy of fuel into electrical energy, and they have promising development prospects in the face of the current serious energy problem. Hydrogen is currently the ideal fuel for SOC power generation, but there are still some major obstacles to hydrogen storage and transportation, which hinders its large-scale application.

[0003] Compared to hydrogen, hydrocarbon fuels are an abundant and inexpensive energy source that can be used efficiently while reducing environmental pollution, thus contributing to the development of large-scale power generation. Methane is the simplest hydrocarbon fuel, a major precursor to natural gas and biogas. Its wide availability, convenient transportation and storage, low price, and reduced environmental pollution make it highly attractive in solid oxide fuel cells. However, directly using methane as fuel inevitably leads to carbon formation, which causes carbon particles to cover electrochemical reaction sites and nickel grain growth, resulting in rapid degradation of the cell's electrochemical performance. Severe carbon deposition on the anode is fatal to the long-term stable operation of the fuel cell. Adding carbon dioxide to the fuel gas to reform methane fuel into hydrogen and carbon monoxide can effectively reduce carbon deposits. To further reduce carbon deposition on the anode of methane solid oxide fuel cells, a fuel reforming catalyst layer can be added to the surface of the anode.

[0004] Due to the limited activity of fuel reforming catalysts currently used, carbon deposition on nickel-based anodes remains unavoidable. Therefore, there is an urgent need to research highly active methane-carbon dioxide dry reforming catalysts and solid oxide fuel cell reforming layer catalyst materials with high carbon deposition resistance to address the anode carbon deposition problem and improve the power generation efficiency of solid oxide fuel cells. Summary of the Invention

[0005] This invention provides a methane-carbon dioxide dry reforming catalyst and a solid oxide fuel cell, as well as a preparation method thereof. The catalyst has high catalytic activity and efficiency in the methane-carbon dioxide dry reforming process, which can effectively avoid the carbon deposition problem at the anode when using methane as fuel, and improve the power generation efficiency and lifespan of the solid oxide fuel cell.

[0006] To address the aforementioned technical problems, one objective of this invention is to provide a methane-carbon dioxide dry reforming catalyst, the catalyst having the chemical formula (La). 0.75 Sr 0.25 ) 1-x / 2 Lix Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ , where 0 < x ≤ 0.2, and δ is a value that maintains the electrical neutrality of the material.

[0007] As a preferred solution, x = 0.1.

[0008] To solve the above technical problems, the second object of the present invention provides a preparation method of a methane-carbon dioxide dry reforming catalyst, comprising the following steps:

[0009] S01. Weigh raw materials of each elemental metal ion according to the stoichiometric ratio of the corresponding elements in the chemical formula of the catalyst, and prepare a metal ion solution using a solvent.

[0010] S02. Add nitric acid to the metal ion solution, heat and stir until the raw materials are completely dissolved, then add a complexing agent to the solution, heat and stir until the complexing agent is completely dissolved, and finally adjust the pH value of the solution to 7 - 8.

[0011] S03. Heat the above-prepared mixed solution until the water is completely evaporated, then make it undergo spontaneous combustion. After cooling, a precursor powder is obtained, and then it is sintered under air conditions to obtain a methane-carbon dioxide dry reforming catalyst.

[0012] As a preferred solution, at least one of the following a) - f) is satisfied:

[0013] a) In S01, the concentration of the metal ion solution is 0.1 - 0.2 mol / L;

[0014] b) In S01, the raw materials are lanthanum oxide, strontium nitrate, lithium carbonate, chromium nitrate, iron nitrate, and nickel nitrate;

[0015] c) In S01, the solvent is water;

[0016] d) In S02, the volume ratio of the nitric acid to the metal ion solution is 1:15;

[0017] e) In S02, the complexing agent is ethylenediaminetetraacetic acid and / or citric acid;

[0018] f) In S03, the sintering temperature is 1200 - 1300 °C, and the sintering time is 4 - 5 h.

[0019] As a preferred solution, in S02, the complexing agent is ethylenediaminetetraacetic acid with a molar amount of 0.5 - 1 times the total metal ions and citric acid with a molar amount of 1 - 1.5 times the total metal ions.

[0020] To address the aforementioned technical problems, a third objective of this invention is to provide a method for preparing a solid oxide fuel cell, employing a methane-carbon dioxide dry weight catalyst, comprising the following steps:

[0021] S1. Mix the methane-carbon dioxide dry heavy catalyst powder and electrolyte powder evenly to obtain a mixed powder, add terpineol ethyl cellulose, and grind to prepare a catalyst composite slurry;

[0022] S2. The catalyst composite slurry is coated on the surface of the anode material and then sintered to prepare an anode material with reforming catalyst. This anode material is used as the anode of a solid oxide fuel cell.

[0023] S3. The solid oxide fuel cell prepared above is subjected to reduction treatment;

[0024] S4. Prepare the fuel composition for a solid oxide fuel cell, introduce the fuel into the anode side of the solid oxide fuel cell, expose the cathode of the solid oxide fuel cell to static air, and generate current through the transfer of electrons in the external circuit to obtain a solid oxide fuel cell.

[0025] As a preferred embodiment, in S1, the methane-carbon dioxide dry reforming catalyst powder and electrolyte powder are mixed at a weight ratio of 3:2, the mass ratio of the mixed powder to terpineol ethyl cellulose is 1:(1.5-2), and the mass fraction of ethyl cellulose in the terpineol ethyl cellulose is 10-20 wt%.

[0026] As a preferred option, at least one of the following a)-g) is satisfied:

[0027] a) In S1, the electrolyte powder is Ce 0.9 Gd 0.1 O 2-δ Powder;

[0028] b) In S2, the sintering temperature is 1200-1300℃ and the sintering time is 3-4h;

[0029] c) In S2, the coating thickness of the reforming catalyst on the anode material is 30-40 μm;

[0030] d) In S3, the reduction treatment is carried out at 700-800℃ under hydrogen conditions for 3-5 hours;

[0031] e) In S4, the fuel component is either hydrogen or a mixture of methane and carbon dioxide;

[0032] f) In S4, the anion is La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3-δ -GDC;

[0033] g) In S2, the anode is a nickel-based material.

[0034] As a preferred embodiment, in S4, the fuel component is a mixture of methane and carbon dioxide in a volume ratio of 1:1.

[0035] To address the aforementioned technical problems, the fourth objective of this invention is to provide a method for preparing a solid oxide fuel cell.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The methane-carbon dioxide dry reforming catalyst of this application can precipitate Fe-Ni alloy during the reaction process, and lithium carbonate can be formed on the catalyst surface under a carbon dioxide atmosphere, which is equivalent to an electrolyte material. Lithium carbonate is a good catalyst for the Boudouard reaction and promotes the occurrence of carbon monoxide reverse disproportionation reaction. At the same time, the reforming layer avoids direct contact between methane and Ni-based anodes, thereby reducing the occurrence of methane cracking reaction and avoiding carbon deposition problems on the anode under a methane atmosphere, thus improving the power generation efficiency and lifespan of solid oxide fuel cells. Attached Figure Description

[0038] Figure 1 X-ray diffraction patterns of the methane-carbon dioxide dry reforming catalysts of Examples 1-2 and Comparative Examples 1-3 of this invention (Note: LSCFN-Li0.4 - Comparative Example 2; LSCFN-Li0.3 - Comparative Example 1; LSCFN-Li0.2 - Example 2; LSCFN-Li0.1 - Example 1; LSCFN-Li0 - Comparative Example 3);

[0039] Figure 2 This is a schematic diagram illustrating the working principle of the methane-carbon dioxide dry reforming catalyst of the present invention in a solid oxide fuel cell.

[0040] Figure 3 The following are the IV curves of the methane-carbon dioxide dry reforming catalysts of Examples 1-2 and Comparative Examples 1-3 of this invention when applied to solid oxide fuel cells with hydrogen as fuel (Note: LSCFN-Li0.4 - Comparative Example 2; LSCFN-Li0.3 - Comparative Example 1; LSCFN-Li0.2 - Example 2; LSCFN-Li0.1 - Example 1; LSCFN-Li0 - Comparative Example 3).

[0041] Figure 4The following are the IV curves of the methane-carbon dioxide dry reforming catalysts of Examples 1-2 and Comparative Examples 1-3 of this invention when applied to solid oxide fuel cells using methane-carbon dioxide as fuel (Note: LSCFN-Li0.4 - Comparative Example 2; LSCFN-Li0.3 - Comparative Example 1; LSCFN-Li0.2 - Example 2; LSCFN-Li0.1 - Example 1; LSCFN-Li0 - Comparative Example 3).

[0042] Figure 5 The following are the anode exhaust gas wind analysis results of the methane-carbon dioxide dry reforming catalysts of Examples 1-2 and Comparative Examples 1-3 of the present invention when applied to solid oxide fuel cells and using methane-carbon dioxide as fuel (Note: LSCFN-Li0.4-Comparative Example 2; LSCFN-Li0.3-Comparative Example 1; LSCFN-Li0.2-Example 2; LSCFN-Li0.1-Example 1; LSCFN-Li0-Comparative Example 3).

[0043] In the above appendix Figure 2 In the middle: 1. Cathode; 2. Barrier layer; 3. Electrolyte; 4. Anode; 5. Reforming catalyst layer. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1

[0046] A methane-carbon dioxide dry reforming catalyst with the chemical formula (La) 0.75 Sr 0.25 ) 0.95 Li 0.1 Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ δ is a value used to maintain the material's electrical neutrality. This value is determined using iodine titration to measure its oxygen vacancy concentration. The preparation method includes the following steps:

[0047] S01, according to the chemical formula (La) 0.75 Sr 0.25 ) 0.95 Li 0.1 Cr 0.5 Fe 0.4 N i 0.1 O 3-δThe stoichiometric ratio of the corresponding elements was determined by weighing out the metal ion raw materials lanthanum oxide, strontium nitrate, lithium carbonate, chromium nitrate, iron nitrate, and nickel nitrate, and preparing a 0.15 mol / L metal ion solution with water.

[0048] S02. Add 25 ml of nitric acid to the metal ion solution obtained in step S1. The volume ratio of nitric acid to metal ion solution is 1:15. Heat and stir until the raw material is completely dissolved. Then add a complexing agent to the solution. The complexing agent includes ethylenediaminetetraacetic acid, which accounts for 0.8 times the amount of total metal ion substance, and citric acid, which accounts for 1 times the amount of total metal ion substance. Heat and stir until the complexing agent is completely dissolved. Finally, add an appropriate amount of ammonia water to adjust the pH of the solution to 7-8.

[0049] S03. Pour the prepared mixed solution into a ceramic evaporator and heat until the water is completely evaporated. Then, it will spontaneously combust. After cooling, the precursor powder is obtained. Then, under air conditions, it is sintered at 1250°C for 5 hours to obtain the methane-carbon dioxide dry reforming catalyst.

[0050] Example 2

[0051] A methane-carbon dioxide dry reforming catalyst is prepared in the same manner as in Example 1, with all steps, reagents, and process parameters being identical. The difference lies in its chemical formula (La). 0.75 Sr 0.25 ) 0.9 Li 0.2 Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ δ is the value used to maintain the material's electrical neutrality, and this value is determined by iodine titration to measure its oxygen vacancy concentration.

[0052] Comparative Example 1

[0053] A methane-carbon dioxide dry reforming catalyst is prepared in the same manner as in Example 1, with all steps, reagents, and process parameters being identical. The difference lies in its chemical formula (La). 0.75 Sr 0.25 ) 0.85 Li 0.3 Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ δ is the value used to maintain the material's electrical neutrality, and this value is determined by iodine titration to measure its oxygen vacancy concentration.

[0054] Comparative Example 2

[0055] A methane-carbon dioxide dry reforming catalyst is prepared in the same manner as in Example 1, with all steps, reagents, and process parameters being identical. The difference lies in its chemical formula (La). 0.75 Sr 0.25 ) 0.8 Li 0.4 Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ δ is the value used to maintain the material's electrical neutrality, and this value is determined by iodine titration to measure its oxygen vacancy concentration.

[0056] Comparative Example 3

[0057] A methane-carbon dioxide dry reforming catalyst with the chemical formula La 0.75 Sr 0.25 Cr 0.5 Fe 0.4 N i 0.1 O 3-δ δ is a value used to maintain the material's electrical neutrality. This value is determined using iodine titration to measure its oxygen vacancy concentration. The preparation method includes the following steps:

[0058] S01, according to the chemical formula La 0.75 Sr 0.25 Cr 0.5 Fe 0.4 N i 0.1 O 3-δ The stoichiometric ratio of the corresponding elements was determined by weighing out the raw materials of lanthanum oxide, strontium nitrate, chromium nitrate, ferric nitrate, and nickel nitrate, and preparing a 0.15 mol / L metal ion solution with water.

[0059] S02. Add 25 ml of nitric acid to the metal ion solution obtained in step S1. The volume ratio of nitric acid to metal ion solution is 1:15. Heat and stir until the raw material is completely dissolved. Then add a complexing agent to the solution. The complexing agent includes ethylenediaminetetraacetic acid, which accounts for 0.8 times the amount of total metal ion substance, and citric acid, which accounts for 1 times the amount of total metal ion substance. Heat and stir until the complexing agent is completely dissolved. Finally, add an appropriate amount of ammonia water to adjust the pH of the solution to 7-8.

[0060] S03. Pour the prepared mixed solution into a ceramic evaporator and heat until the water is completely evaporated. Then, it will spontaneously combust. After cooling, the precursor powder is obtained. Then, under air conditions, it is sintered at 1250°C for 5 hours to obtain the methane-carbon dioxide dry reforming catalyst.

[0061] Application examples

[0062] The methane-carbon dioxide dry reforming catalysts obtained in Examples 1-2 and Comparative Examples 1-3 are applied in the preparation method of solid oxide fuel cells, comprising the following steps:

[0063] S1, mix methane-carbon dioxide dry heavy catalyst powder and electrolyte GDC (Ce 0.9 Gd 0.1 O 2-δ The powder was placed in a mortar at a weight ratio of 3:2, mixed evenly, and then terpineol ethyl cellulose with a concentration of 10 wt% ethyl cellulose was added at twice the weight of the mixed powder. The mixture was then ground to prepare a catalyst composite slurry.

[0064] S2. The catalyst composite slurry was coated four times on the surface of the nickel-based anode and then sintered at 1250℃ for 3 hours to prepare an anode material with a reforming catalyst. The thickness of the reforming catalyst layer was 40μm. This anode material was used as the anode of a solid oxide fuel cell.

[0065] S3. The solid oxide fuel cell prepared above is treated at 750°C and under hydrogen conditions for 5 hours. The fuel composition of the solid oxide fuel cell is prepared according to the volume ratio of methane to carbon dioxide of 1:1 and controlled by a mass flow meter.

[0066] S4. Introduce fuel into the anode side of the battery, using La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -GDC is used as the cathode, and Zr is used as the electrolyte. 0.85 Y 0.15 O2, GDC, and the electrolyte GDC serve as a barrier layer. The cathode of the solid oxide fuel cell is exposed to static air. The transfer of electrons in the external circuit can generate current, thus producing a solid oxide fuel cell.

[0067] Performance testing

[0068] 1. Electrochemical Performance Measurement: The solid oxide fuel cells prepared in Examples 1-2 and Comparative Examples 1-3 were tested using an electrochemical workstation (Zahner Zennium, Germany) under hydrogen (3 wt% H2O + 97 wt% H2) and methane-carbon dioxide (CH4-CO2 = 1:1, volume ratio) atmospheres or hydrogen atmospheres. The experimental results are attached. Figure 3-4 As shown.

[0069] From the appendix Figure 3 , 4As can be seen from this, the battery with methane-carbon dioxide dry reforming catalyst prepared in Example 1 of the present invention has the highest maximum power density under the same conditions compared with other examples and comparative examples, and therefore has better electrochemical performance.

[0070] 2. Catalytic performance determination: The anode exhaust gas composition of the solid oxide fuel cells prepared in Examples 1-2 and Comparative Examples 1-3 was tested using a gas chromatograph (Shimadzu GC2014, Japan) at an operating temperature of 800°C under a methane-carbon dioxide (CH4-CO2 = 1:1, volume ratio) atmosphere. The experimental results are attached. Figure 5 As shown.

[0071] From the appendix Figure 5 As can be seen from the above, the battery with methane-carbon dioxide dry reforming catalyst prepared in Example 1 of the present invention exhibits more complete methane-carbon dioxide fuel catalysis under the same conditions, with a higher proportion of H2 and CO in the syngas, indicating higher catalytic activity.

[0072] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A methane-carbon dioxide dry reforming catalyst, characterized in that, The chemical formula of the catalyst is (La 0.75 Sr 0.25 ) 1-x / 2 Li x Cr 0.5 Fe 0.4 Ni 0.1 O 3-δ , where 0 < x ≤ 0.2 and δ is a value to maintain the electrical neutrality of the material.

2. The methane-carbon dioxide dry reforming catalyst as described in claim 1, characterized in that, The x=0.

1.

3. A method for preparing a methane-carbon dioxide dry reforming catalyst as described in claim 1 or 2, characterized in that, Includes the following steps: S01. Weigh the metal ion raw materials according to the stoichiometric ratio of the corresponding elements in the chemical formula of the catalyst, and prepare the metal ion solution using a solvent. S02. Add nitric acid to the metal ion solution, heat and stir until the raw material is completely dissolved, then add a complexing agent to the solution, heat and stir until the complexing agent is completely dissolved, and finally adjust the pH of the solution to 7-8. S03. The prepared mixed solution is heated until the water is completely evaporated, and then it is allowed to spontaneously combust. After cooling, the precursor powder is obtained, and then sintered under air conditions to obtain the methane-carbon dioxide dry reforming catalyst.

4. The method for preparing a methane-carbon dioxide dry reforming catalyst as described in claim 3, characterized in that, Satisfy at least one of the following a)-f): a) In SO1, the concentration of the metal ion solution is 0.1-0.2 mol / L; b) In SO1, the raw materials are lanthanum oxide, strontium nitrate, lithium carbonate, chromium nitrate, iron nitrate, and nickel nitrate; c) In S01, the solvent is water; d) In SO2, the volume ratio of the nitric acid to the metal ion solution is 1:15; e) In SO2, the complexing agent is ethylenediaminetetraacetic acid and / or citric acid; f) In SO3, the sintering temperature is 1200-1300℃ and the sintering time is 4-5h.

5. The method for preparing a methane-carbon dioxide dry reforming catalyst as described in claim 3, characterized in that, In S02, the complexing agent is ethylenediaminetetraacetic acid, which accounts for 0.5-1 times the total amount of metal ions, and citric acid, which accounts for 1-1.5 times the total amount of metal ions.

6. A method for preparing a solid oxide fuel cell, characterized in that, The method of using a methane-carbon dioxide dry weight catalyst as described in claim 1 or 2 includes the following steps: S1. Mix the methane-carbon dioxide dry heavy catalyst powder and electrolyte powder evenly to obtain a mixed powder, add terpineol ethyl cellulose, and grind to prepare a catalyst composite slurry; S2. The catalyst composite slurry is coated on the surface of the anode material and then sintered to prepare an anode material with reforming catalyst. This anode material is used as the anode of a solid oxide fuel cell. S3. The solid oxide fuel cell prepared above is subjected to reduction treatment; S4. Prepare the fuel composition for a solid oxide fuel cell, introduce the fuel into the anode side of the solid oxide fuel cell, expose the cathode of the solid oxide fuel cell to static air, and generate current through the transfer of electrons in the external circuit to obtain a solid oxide fuel cell.

7. The method for preparing a solid oxide fuel cell as described in claim 6, characterized in that, In S1, the methane-carbon dioxide dry reforming catalyst powder and electrolyte powder are mixed at a weight ratio of 3:2, the mass ratio of the mixed powder to terpineol ethyl cellulose is 1:(1.5-2), and the mass fraction of ethyl cellulose in the terpineol ethyl cellulose is 10-20 wt%.

8. The method for preparing a solid oxide fuel cell as described in claim 6, characterized in that, Satisfy at least one of the following a)-g): a) In S1, the electrolyte powder is Ce 0.9 Gd 0.1 O 2-δ Powder; b) In S2, the sintering temperature is 1200-1300℃ and the sintering time is 3-4h; c) In S2, the coating thickness of the reforming catalyst on the anode material is 30-40 μm; d) In S3, the reduction treatment is carried out at 700-800℃ under hydrogen conditions for 3-5 hours; e) In S4, the fuel component is either hydrogen or a mixture of methane and carbon dioxide; f) In S4, the cathode is La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -GDC; g) In S2, the anode is a nickel-based material.

9. The method for preparing a solid oxide fuel cell as described in claim 6, characterized in that, In S4, the fuel composition is a mixture of methane and carbon dioxide in a volume ratio of 1:

1.

10. A solid oxide fuel cell prepared by a method according to any one of claims 6-9.

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