Tubular ammonia fuel cell and preparation method of catalyst layer thereof

Abstract

The invention relates to a tubular ammonia fuel cell and a catalyst layer preparation method thereof. The tubular ammonia fuel cell comprises an electrolyte tube, a cathode layer, an anode layer and a catalyst layer, the electrolyte tube is made of barium, zirconium, cerium, yttrium and ytterbium, the thickness of the electrolyte tube is 270-350 microns, the density of the electrolyte tube is more than 95%, and the length of the electrolyte tube is about 54-60 mm; the cathode layer is located on the outer wall of the electrolyte tube, and the cathode layer is made of praseodymium barium strontium cobalt iron-barium zirconium cerium yttrium ytterbium; the anode layer is positioned on the inner wall of the electrolyte tube; the catalyst layer is located on the inner wall of the anode layer and is made of cobalt-barium zirconium yttrium composite powder. The tubular battery has the advantages that the tubular battery can better distribute thermal stress, has higher mechanical strength and can be better sealed, and fuel gas is fully utilized. Meanwhile, the catalyst is coated on the surface of the anode, so that the effects of saving the cost, protecting the anode, improving the ammonia catalytic activity and the like can be achieved.

Description

Technical Field

[0001] The present invention relates to a tubular ammonia fuel cell and a method for preparing a catalyst layer thereof. Background Art

[0002] At present, the more common proton-conducting solid oxide fuel cell (PCFC) is a flat cell, which has advantages such as high power density and fast startup. However, in practical applications, there are disadvantages such as thermal stress delamination, difficult sealing, and insufficient utilization of fuel gas.

[0003] The proton-conducting solid oxide fuel cell (PCFC) is a conversion device that can efficiently use fuel gas and directly convert chemical energy into electrical energy at low temperature and low cost. However, the disadvantages such as the difficult transportation and storage of hydrogen restrict its application in PCFC. Ammonia with a higher energy density that is easier to store and transport is a better alternative. However, the existing nickel-based anodes will show obvious performance degradation in the harsh environment of ammonia. Therefore, introducing an anode functional layer on the anode surface can improve ammonia catalytic activity and protect the anode as much as possible. Currently, the best ammonia catalyst is the ruthenium-based catalyst, but its expensive price restricts its application. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies of the prior art and provide a tubular ammonia fuel cell and a method for preparing a catalyst layer thereof. The tubular cell can better distribute thermal stress, has high mechanical strength, and can be better sealed to fully utilize fuel gas. At the same time, coating the catalyst on the anode surface can save costs, protect the anode, and improve ammonia catalytic activity.

[0005] To achieve the above object, the first technical solution of the present invention is realized as follows. It is a tubular ammonia fuel cell, which is characterized by comprising: An electrolyte tube; the material of the electrolyte tube is barium zirconium cerium yttrium ytterbium, the thickness of the electrolyte tube is 270μm - 350μm, the density of the electrolyte tube is above 95%, and the length of the electrolyte tube is about 54mm - 60mm; A cathode layer; the cathode layer is located on the outer wall of the electrolyte tube, the material of the cathode layer is praseodymium barium strontium cobalt iron - barium zirconium cerium yttrium ytterbium, the ratio of praseodymium barium strontium cobalt iron to barium zirconium cerium yttrium ytterbium is about 60% ± 5% to 40% ± 5%, the porosity of the cathode layer is 20% - 30%, and the thickness of the cathode layer is 30μm - 50μm; An anode layer; the anode layer is located on the inner wall of the electrolyte tube, the material of the anode layer is nickel oxide - barium zirconium cerium yttrium ytterbium, the ratio of nickel oxide to barium zirconium cerium yttrium ytterbium is between 60% ± 5% and 40% ± 5%, the porosity of the anode layer is 30% - 40%, and the thickness of the anode layer is about 30μm - 50μm; and Catalyst layer; the catalyst layer is located on the inner wall of the anode layer, and the material of the catalyst layer is cobalt-barium-zirconium-yttrium composite powder. The ratio of cobalt to barium-zirconium-yttrium composite powder is 20% ± 5% to 80% ± 5%, and the thickness of the catalyst layer is 20 - 30 μm.

[0006] To achieve the above object, the second technical solution of the present invention is implemented as follows. It is a method for preparing a catalyst for a tubular ammonia fuel cell, which is characterized by including the following steps: Step 1 Sol-gel method. Cobalt-barium-zirconium-yttrium composite powder uses citric acid as a chelating agent to make citric acid complex with metal ions to form a three-dimensional network structure of metal ion-citric acid complex gel, obtaining a cobalt-barium-zirconium-yttrium precursor. The ratio of cobalt to barium-zirconium-yttrium composite powder is 20% ± 5% to 80% ± 5%. Step 2 The precursor obtained in Step 1 is placed in a hydrogen atmosphere and calcined at a temperature of 700 ± 10 °C for 2 - 2.5 h to obtain catalyst powder. Step 3 Doctor blade method. The catalyst powder is evenly coated on the surface of the anode layer using a brush or a spatula and sintered at 1400 - 1450 °C for 4 - 5 h to obtain a stable structure.

[0007] The advantages of the present invention compared with the prior art are as follows: The tubular battery can distribute thermal stress better, has high mechanical strength, can be sealed well, and can make full use of fuel gas. At the same time, coating this catalyst on the anode surface can play roles such as cost saving, anode protection, and improvement of ammonia catalytic activity. Brief Description of the Drawings

[0008] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a top view of the present invention; Figure 3 is Figure 2 the A - A cross-sectional view of Figure 4 is Figure 3 the cross-sectional view of the partial B of Detailed Description of the Invention

[0009] The following further describes the specific embodiments of the present invention with reference to the drawings. It should be noted here that the description of these embodiments is for helping to understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Embodiment

[0010] As Figures 1 to 4As shown, it is a tubular ammonia fuel cell, including: An electrolyte tube 2; the material of the electrolyte tube 2 is barium zirconium cerium yttrium ytterbium, the thickness of the electrolyte tube 2 is 270μm or 280μm or 290μm or 300μm or 310μm or 320μm or 330μm or 340μm or 350μm, the density of the electrolyte tube 2 is above 95%, and the length of the electrolyte tube 2 is about 54mm - 60mm; A cathode layer 1; the cathode layer 1 is located on the outer wall of the electrolyte tube 2, the material of the cathode layer 1 is praseodymium barium strontium cobalt iron - barium zirconium cerium yttrium ytterbium, the ratio of the praseodymium barium strontium cobalt iron to barium zirconium cerium yttrium ytterbium is about 60% ± 5% to 40% ± 5%, the porosity of the cathode layer 1 is 20% or 25% or 30%, and the thickness of the cathode layer 1 is 30μm or 35μm or 40μm or 45μm or 50μm; An anode layer 3; the anode layer 3 is located on the inner wall of the electrolyte tube 2, the material of the anode layer 3 is nickel oxide - barium zirconium cerium yttrium ytterbium, the ratio of the nickel oxide to barium zirconium cerium yttrium ytterbium is between 60% ± 5% and 40% ± 5%, the porosity of the anode layer 3 is 30% or 35% or 40%, and the thickness of the anode layer 3 is about 30μm or 35μm or 40μm or 45μm or 50μm; and A catalyst layer 4; the catalyst layer 4 is located on the inner wall of the anode layer 3, the material of the catalyst layer 4 is cobalt - barium zirconium yttrium composite powder, the ratio of the cobalt to the barium zirconium yttrium composite powder is 20% ± 5% to 80% ± 5%, and the thickness of the catalyst layer 4 is 20μm or 25μm or 30μm.

[0011] During operation, please supplement the fuel cell chemical reaction formula to reflect the generation of electricity.

[0012] (1)2NH3→N2+3H2 (2)H2→2H + +2e - (3)O2+4H + +4e - →2H2O Fix the fuel cell tube in an electric furnace, introduce nitrogen for protection, heat up to 300°C, then start introducing ammonia. Ammonia decomposes into hydrogen and nitrogen under the action of the catalyst. Hydrogen reduces nickel oxide to nickel metal under high - temperature conditions. This process lasts for 1 - 2h to completely reduce nickel oxide to nickel metal, enabling it to collect the current generated at the anode, and then the current test can be started. Example

[0013] As Figures 1 to 4 shown, it is a method for preparing a catalyst of a tubular ammonia fuel cell. The method is characterized by including the following steps: Step 1 Sol-gel method: Using citric acid as a chelating agent for cobalt and barium zirconium yttrium composite powder, citric acid is complexed with metal ions to form a metal ion-citric acid complex gel with a three-dimensional network structure, obtaining a cobalt-barium zirconium yttrium precursor. The ratio of cobalt to barium zirconium yttrium composite powder is 20% to 80% or 15% to 85% or 25% to 75%. Step Two The precursor obtained in Step One is calcined at a temperature of 690 °C or 700 °C or 710 °C for 2 h or 2.25 h or 2.5 h in a hydrogen atmosphere to obtain catalyst powder. Step Three Doctor blade method: The catalyst powder is evenly coated on the surface of the anode layer 3 using a brush or a spatula, and sintered at 1400 °C or 1425 °C or 1450 °C for 4 h or 4.5 h or 5 h to obtain a stable structure.

[0014] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those of ordinary skill in the art, various changes, modifications, substitutions, and variations of these embodiments still fall within the protection scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A tubular ammonia fuel cell and a method for preparing its catalyst layer, characterized in that Comprising: An electrolyte tube (2); the material of the electrolyte tube (2) is barium zirconium cerium yttrium ytterbium, the thickness of the electrolyte tube (2) is 270 μm - 350 μm, the density of the electrolyte tube (2) is above 95%, and the length of the electrolyte tube (2) is about 54 mm - 60 mm; A cathode layer (1); the cathode layer (1) is located on the outer wall of the electrolyte tube (2), the material of the cathode layer (1) is praseodymium barium strontium cobalt iron - barium zirconium cerium yttrium ytterbium, the ratio of praseodymium barium strontium cobalt iron to barium zirconium cerium yttrium ytterbium is about 60% ± 5% to 40% ± 5%, the porosity of the cathode layer (1) is 20% - 30%, and the thickness of the cathode layer (1) is 30 μm - 50 μm; An anode layer (3); the anode layer (3) is located on the inner wall of the electrolyte tube (2), the material of the anode layer (3) is nickel oxide - barium zirconium cerium yttrium ytterbium, the ratio of nickel oxide to barium zirconium cerium yttrium ytterbium is between 60% ± 5% and 40% ± 5%, the porosity of the anode layer (3) is 30% - 40%, and the thickness of the anode layer (3) is about 30 μm - 50 μm; and A catalyst layer (4); the catalyst layer (4) is located on the inner wall of the anode layer (3), the material of the catalyst layer (4) is cobalt - barium zirconium yttrium composite powder, the ratio of cobalt to barium zirconium yttrium composite powder is 20% ± 5% to 80% ± 5%, and the thickness of the catalyst layer (4) is 20 - 30 μm.

2. The preparation method of the catalyst layer of the tubular ammonia fuel cell according to claim 1, characterized in that Comprising the following steps: Step 1 The sol - gel method, using citric acid as a chelating agent for cobalt and barium zirconium yttrium composite powder, enabling citric acid to complex with metal ions to form a three - dimensional network - structured metal ion - citric acid complex gel, obtaining a cobalt - barium zirconium yttrium precursor, and the ratio of cobalt to barium zirconium yttrium composite powder is 20% ± 5% to 80% ± 5%; Step 2 Placing the precursor from Step 1 in a hydrogen atmosphere and calcining it at a temperature of 700 ± 10 °C for 2 - 2.5 h to obtain catalyst powder; Step 3 The doctor - blade method, using a brush or a spatula to evenly apply the catalyst powder on the surface of the anode layer (3) and sintering it at 1400 - 1450 °C for 4 - 5 h to obtain a stable structure.

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