Anode material of solid oxide electrolytic cell, solid oxide electrolytic cell and preparation method and application of solid oxide electrolytic cell

Abstract

The invention belongs to the technical field of solid oxide batteries and electrolytic cells, and relates to the field of carbon dioxide reduction and methane oxidative coupling, in particular to a solid oxide electrolytic cell anode material, a solid oxide electrolytic cell and a preparation method and application of the solid oxide electrolytic cell anode material. The general formula of the chemical formula of the anode material is Ln < 0.6 > Sr < 0.4 > Mn < 1 + x > O < 3-delta >, x is-0.05 to 0.05, and Ln is one of Pr and Sm; and delta represents the non-stoichiometric ratio of oxygen in the material. According to the solid oxide electrolytic cell anode material, the potential during preparation of ethylene and ethane through coupling of carbon dioxide and methane oxide can be reduced, the selectivity of ethane and ethylene in oxidative coupling of methane can be improved on the basis of stoichiometric regulation and control on Mn, and the economical efficiency of a product on one side of an anode is improved.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide batteries and electrolytic cells, and also relates to the fields of carbon dioxide reduction and methane oxidative coupling. Specifically, it relates to a solid oxide electrolytic cell anode material, a solid oxide electrolytic cell and its preparation method, and the application of the aforementioned solid oxide electrolytic cell anode material and solid oxide electrolytic cell in the production of hydrocarbon compounds by carbon dioxide oxidative coupling with methane. Background Technology

[0002] With the growing global demand for sustainable energy solutions, solid oxide electrolyzer (SOEC) technology has become a hot topic in research and industry due to its unique advantages of high efficiency, operational flexibility, and environmental friendliness. The core function of SOEC is to directly convert electrical energy generated from renewable energy sources (such as solar and wind power) into chemical energy. In this process, the electrolytic conversion of CO2 is particularly noteworthy because it offers the possibility of achieving a closed carbon cycle, reducing greenhouse gas emissions, and producing carbon-neutral fuels. In this conversion pathway, the anode (often referred to as the anode) is a key component, and its material selection and design directly affect electrolysis efficiency, stability, and long-term operating costs. Taking La as an example... 0.6 Sr 0.4 MnO 3-δ Perovskite oxides, represented by [specific type], are used as anode materials in solid oxide electrolytic cells due to their good thermochemical stability and electronic conductivity.

[0003] In recent years, the production of ethylene via coupled electrochemical methane oxidation (EC-OCM) on the anode side of a solid oxide electrolyzer (SOEC) has attracted considerable attention. In this system, the activation and oxidation of methane does not require direct oxygen introduction, but can be achieved through oxygen ions provided by the solid oxide electrolyte. Utilizing carbon dioxide electrolysis on the cathode side to provide oxygen ions not only combines endothermic and exothermic reactions to ensure thermal control of the electrolyzer, but also reduces carbon dioxide to carbon monoxide, transforming the system into a carbon-negative technology.

[0004] La 0.6 Sr 0.4 MnO 3-δPerovskite materials, as a traditional catalyst, are commonly used in the catalytic combustion of methane, with carbon dioxide as the primary catalytic oxidation product. The high activity of these materials stems from their surface characteristics: a high concentration of oxygen vacancies and highly active adsorbed oxygen, thus endowing them with high oxidizing power. However, when attempting to apply these materials to the oxidative coupling reaction of methane to produce ethane and ethylene, their high oxidizing power becomes a disadvantage. Due to over-oxidation, methane often fails to selectively convert to ethane and ethylene in the reaction, resulting in low selectivity for these two products. Substituting transition metals into perovskite materials, such as replacing Mn with Co, Fe, or Ni, can alter the species of actively adsorbed oxygen on their surface, potentially improving their catalytic activity. However, it is noteworthy that Co, Fe, and Ni-based perovskite oxide materials are commonly used as catalysts for the catalytic combustion of methane. This suggests that simply adjusting the types of actively adsorbed oxygen through transition metal substitution may not be sufficient to change the reaction pathway of over-catalytic oxidation of methane. On the other hand, although Al-based perovskites such as LaAlO... 3-δ It is believed to have the potential to convert methane into ethane and ethylene, but unfortunately, it is an insulator and therefore cannot be used as an anode material.

[0005] Therefore, it is essential to develop solid oxide electrolytic cell anode materials suitable for the coupling of methane oxidation with carbon dioxide to produce hydrocarbons, and even more importantly, to develop manganese-based perovskite materials to make them more suitable for the reaction of methane oxidation to produce ethane and ethylene. Summary of the Invention

[0006] The inventors of this invention, through research, unexpectedly discovered a replacement for the traditional La... 0.6 Sr 0.4 Mn 1+x O 3-δ (x=0) In the material, replacing La with solid oxides of lanthanide metals Pr or Sm as the anode material of the electrolytic cell can reduce the electrolysis potential of the methane oxidation coupled with carbon dioxide reduction. Based on the stoichiometric control of Mn, it can also improve the selectivity of ethane and ethylene in the methane oxidative coupling and improve the economics of the products on the anode side. The Ln of this invention... 0.6 Sr 0.4 Mn 1+x O 3-δ (Ln is one of Pr and Sm) Solid oxide electrolytic cell anode material based on traditional La 0.6 Sr 0.4 MnO 3-δ With material improvements, traditional La can be used. 0.6 Sr 0.4 MnO 3-δThe preparation method of the material has good application prospects in the field of solid oxide batteries.

[0007] Based on the above research and invention, the first aspect of this invention is to provide a solid oxide electrolytic cell anode material, wherein the anode material has the general chemical formula Ln. 0.6 Sr 0.4 Mn 1+x O 3-δ , where x is -0.05 to 0.05, Ln is one of Pr and Sm; δ represents the non-stoichiometric ratio of oxygen in the material.

[0008] According to the present invention, δ represents the non-stoichiometric ratio of oxygen in the material. Those skilled in the art can determine the value of “δ” through iodine titration experiments, and usually 0 < δ < 1.

[0009] According to some preferred embodiments of the present invention, Ln is Sm, and x is 0 to 0.05, more preferably x is 0 to 0.05 and not 0. By increasing the stoichiometric control of manganese, the selectivity of ethane and ethylene can be further improved.

[0010] According to some preferred embodiments of the present invention, Ln is Pr, and x is -0.05 to 0.05. When Ln is Pr, the selectivity of ethane to ethylene can be further improved.

[0011] According to some further preferred embodiments of the present invention, Ln is Pr, x is 0 to 0.05, and more preferably x is not 0. Based on Pr... 0.6 Sr 0.4 MnO 3-δ Stoichiometric control of Mn can further improve the selectivity of ethane-ethylene in methane oxidative coupling, reduce the working potential of the electrolytic cell, and improve the economic efficiency of the products on the anode side.

[0012] According to some preferred embodiments of the present invention, the anode material of the solid oxide electrolytic cell is a perovskite oxide; preferably,

[0013] The solid oxide electrolytic cell anode material is prepared by using Ln element source, Sr element source, and Mn element source in accordance with Ln 0.6 Sr 0.4 Mn 1+x O 3-δ The stoichiometric ratio is obtained by at least one of the following methods: sol-gel method, co-precipitation, solid-phase method, and low-temperature self-propagating combustion method. As mentioned above, this invention is based on the traditional La... 0.6 Sr 0.4 MnO 3-δ With material improvements, traditional La can be used. 0.6 Sr 0.4 MnO3-δ The preferred method for preparing the material is by gelation.

[0014] The inventors of this invention discovered through research that, replacing the traditional La... 0.6 Sr 0.4 Mn 1+x O 3-δ (x=0) Replacing La in the material with lanthanide metals Pr or Sm can improve the selectivity of ethane-ethylene oxidation in the methane oxidation reaction. Simultaneously, Pr substitution can lower the operating potential of the methane oxidation coupled with carbon dioxide reduction. Based on the substitution of Pr... 0.6 Sr 0.4 MnO 3-δ Stoichiometric control of Mn can further improve the selectivity of ethane-ethylene in methane oxidative coupling, reduce the operating potential of the electrolytic cell, and improve the economic efficiency of the products on the anode side. The Ln of this invention... 0.6 Sr 0.4 Mn 1+x O 3-δ (Ln is one of Pr and Sm) Solid oxide electrolytic cell anode material based on traditional La 0.6 Sr 0.4 MnO 3-δ With material improvements, traditional La can be used. 0.6 Sr 0.4 MnO 3-δ The preparation method of the material has good application prospects in the field of solid oxide batteries.

[0015] A second aspect of the present invention is to provide a method for preparing the solid oxide electrolytic cell anode material as described in the first aspect, comprising following the steps of Ln 0.6 Sr 0.4 Mn 1+x O 3-δ The Ln, Sr, and Mn element sources are mixed with optional citric acid and glucose in a stoichiometric ratio, with the amounts of citric acid and glucose not both being 0. The mixture is heated to form a wet gel, which is then foamed, dried, and sintered to obtain the solid oxide electrolytic cell anode material.

[0016] According to some preferred embodiments of the present invention, the Ln element source is a soluble metal salt of Ln metal element, preferably a nitrate.

[0017] According to some preferred embodiments of the present invention, the Sr element source is a soluble metal salt of Sr, preferably strontium nitrate.

[0018] According to some preferred embodiments of the present invention, the Mn element source is a soluble metal salt of Mn, preferably manganese nitrate; more preferably, the Mn element source is a commercially available 50wt% aqueous solution of manganese nitrate.

[0019] According to some preferred embodiments of the present invention, the ratio of the amount of citric acid and glucose to the total amount of metal element source is (0-6):1, preferably (0.5-2):1, wherein the total amount of metal element source is equal to the sum of the total amount of Ln element source, Sr element source and Mn element source in terms of metal element.

[0020] According to some preferred embodiments of the present invention, the conditions for foaming and drying include: a temperature of 100-270°C and / or a time of 1-4 hours.

[0021] According to some preferred embodiments of the present invention, the sintering conditions include: a heating rate of 1-10°C / min, and / or a sintering holding temperature of 850-1350°C and a holding time of 1-10h, and / or a cooling rate of 1-10°C / min.

[0022] According to some preferred embodiments of the present invention, the material is further pulverized before sintering after being foamed and dried.

[0023] According to some preferred embodiments of the present invention, the sintered material is further pulverized after sintering to obtain a powdered solid oxide electrolytic cell anode material.

[0024] A third aspect of the present invention is to provide a solid oxide electrolytic cell, comprising an anode, an electrolyte, and a cathode, wherein the electrolyte is a supported oxygen ion-conducting electrolyte used to support the anode and cathode.

[0025] The anode contains the solid oxide electrolytic cell anode material described in the first aspect or the solid oxide electrolytic cell anode material obtained by the preparation method described in the second aspect.

[0026] According to some preferred embodiments of the present invention, the electrolyte is at least one of zirconium oxide YSZ type electrolyte and lanthanum strontium gallium magnesium LSGM type electrolyte; and / or, the cathode is at least one of yttrium-coated zirconium oxide YSZ electrolyte material, nickel oxide-YSZ, strontium iron molybdenum oxide, and the same material as the anode material; more preferably,

[0027] The cathode and the electrolyte are derived from solid oxide half-cells (which can be commercially available or self-made using existing technology). More preferably, the solid oxide half-cell is at least one of the following: a nickel-YSZ cathode support half-cell coated with yttrium zirconium oxide YSZ electrolyte; a YSZ electrolyte support half-cell with nickel oxide-YSZ as the cathode; a YSZ support half-cell with strontium iron molybdenum oxide as the cathode; a lanthanum-strontium gallium magnesium LSGM electrolyte support half-cell with strontium iron molybdenum oxide as the cathode; a YSZ support half-cell with the same material as the anode as the cathode; and a lanthanum-strontium gallium magnesium LSGM electrolyte support half-cell with the same material as the anode as the cathode.

[0028] A fourth aspect of the present invention is to provide a method for preparing the solid oxide electrolytic cell described in the first aspect, characterized in that it includes: mixing a mixture comprising the solid oxide electrolytic cell anode material and an optional pore-forming agent with a binder to obtain an anode printing paste; coating the anode printing paste onto the anode side of the electrolyte; and drying and sintering to obtain the electrolytic cell anode; preferably,

[0029] The electrolyte is derived from a solid oxide half-cell cell having a cathode and an electrolyte. In this case, the anode printing paste is coated onto the anode side of the electrolyte, and after drying and sintering, a solid oxide electrolytic cell is obtained.

[0030] As an example, the process of preparing a solid oxide electrolytic cell using the solid oxide electrolytic cell anode material of the present invention can be as follows:

[0031] (1) Take solid oxide electrolytic cell anode material powder and pore-forming agent, place them in a ball mill jar, add an appropriate amount of dispersant (e.g., anhydrous ethanol), and then place the ball mill jar in a ball mill for thorough ball milling;

[0032] (2) After ball milling, remove the ball mill jar, dry it in a forced-air drying oven, and then grind the obtained mixed powder evenly with an agate mortar.

[0033] (3) Take an appropriate amount of the mixed powder and binder such as turpentine percolate and ethyl cellulose mixture, place them in an agate mortar and grind and mix them evenly to obtain anodized printing paste;

[0034] (4) The mixed slurry is screen-printed onto the solid oxide electrolytic cell half-cell and then dried in an oven.

[0035] (5) Repeat the contents of (4) 3 to 6 times, place the prepared solid oxide electrolytic cell sheet in a muffle furnace for high-temperature sintering, and take it out after sintering is completed to obtain a solid oxide electrolytic cell sheet loaded with solid oxide electrolytic cell anode material.

[0036] According to some preferred embodiments of the present invention, in step (1): the mass ratio of the solid oxide electrolytic cell anode material powder to the dispersant is 1:2 to 1:20; and / or,

[0037] The dispersant is selected from at least one of anhydrous ethanol, methanol, isopropanol, acetone, and water.

[0038] Dispersants are the milling media added in wet ball milling processes to make the materials mix more evenly. Anhydrous ethanol can be used as a dispersant, or other reagents such as methanol, isopropanol, acetone, and water. Considering that anhydrous ethanol has a low boiling point, is more environmentally friendly, and dries more easily after ball milling, it is preferred.

[0039] According to some preferred embodiments of the present invention, the pore-forming agent is selected from at least one of starch, graphite, and PMMA powder.

[0040] According to some preferred embodiments of the present invention, the amount of the pore-forming agent added is 0 to 25 wt% of the mass of the solid oxide electrolytic cell anode material.

[0041] According to some preferred embodiments of the present invention, the binder is turpentine percolate and ethyl cellulose, preferably with a mass ratio of turpentine percolate to ethyl cellulose of (15-9):1. As an example, the preparation method of the mixture of turpentine percolate and ethyl cellulose is as follows: turpentine percolate and ethyl cellulose in a mass ratio of 15:1 are taken, stirred evenly with a stirring paddle at 60°C, allowed to stand to defoam, and cooled to room temperature to obtain the mixture of turpentine percolate and ethyl cellulose, which is used as the binder.

[0042] According to some preferred embodiments of the present invention, the mass ratio of the mixture to the binder is (0.1 to 1.5):1, and the preferred ratio is (0.5 to 1):1.

[0043] According to some preferred embodiments of the present invention, the drying conditions include: a temperature of 65–85°C and / or a time of 5–10 min.

[0044] According to some preferred embodiments of the present invention, the sintering conditions include: a heating rate of 1 to 10 °C / min during sintering, a holding temperature of 1000 to 1150 °C, a holding time of 2 to 5 h, and a cooling rate of 1 to 10 °C / min.

[0045] The fifth aspect of the present invention is to provide the application of the solid oxide electrolytic cell anode material of the first aspect, or the solid oxide electrolytic cell anode material obtained by the preparation method of the second aspect, or the solid oxide electrolytic cell obtained by the preparation method of the third aspect, or the solid oxide electrolytic cell obtained by the preparation method of the fourth aspect, in the production of hydrocarbon compounds by coupling the oxidation of methane with carbon dioxide, wherein the hydrocarbon compounds preferably include ethylene and ethane.

[0046] According to some preferred embodiments of the present invention, the application includes:

[0047] At 750-850℃, the cathode side of the solid oxide electrolytic cell is placed in an atmosphere containing carbon dioxide, and the anode side is placed in a methane atmosphere. An external voltage is applied between the cathode and the anode to carry out a methane oxidative coupling reaction at the solid oxide anode to obtain a gas containing ethylene and ethane.

[0048] Preferably, the applied voltage is 0.1-2V, more preferably 0.9-1.2V; and / or,

[0049] Preferably, the atmosphere containing carbon dioxide is a carbon dioxide-hydrogen mixture atmosphere, and more preferably, the volume fraction of carbon dioxide is 50%-100%, more preferably 70%-95%.

[0050] The beneficial effects of this invention are at least as follows:

[0051] This invention provides a type of high-temperature solid oxide electrolytic cell anode material. This solid oxide electrolytic cell anode material can reduce the electrolysis potential of carbon dioxide electrolysis by coupling the methane oxidation reaction, and can also improve the selectivity of ethane and ethylene in methane oxidative coupling. Further changing the type of lanthanide metal can further improve the selectivity of ethane and ethylene in methane oxidative coupling, thereby improving the economic efficiency of the products on the anode side. It has good application prospects in the field of solid oxide batteries. Detailed Implementation

[0052] The preferred embodiments of the present invention will now be described in detail with reference to examples. It should be understood that the following embodiments are given for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and intent. 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.

[0053] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available or prepared according to conventional methods in the art.

[0054] Example 1

[0055] This embodiment provides a method for preparing a manganese-based perovskite oxide anode material with the chemical formula Pr. 0.6 Sr 0.4 Mn 1.05 O 3-δ The invention describes the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and the method for coupling methane oxidation with carbon dioxide reduction.

[0056] (1) Manganese-based perovskite oxide anode material Pr 0.6 Sr 0.4 Mn 1.05 O 3-δ Preparation:

[0057] According to the stoichiometric ratio, praseodymium nitrate hexahydrate, strontium nitrate, and a 50wt% manganese nitrate aqueous solution were weighed out. The stoichiometric ratio of Mn was adjusted to 1.05. The weighed raw materials were mixed to obtain a mixed solution. Citric acid and glucose with an equimolar amount of metal ions were added and stirred evenly. The mixture was heated to 100℃ and maintained for 1 hour until the solution gradually thickened to a wet gel state. The beaker was then transferred to a 180℃ oven for drying and foaming for 2 hours, forming a dry gel. The dry gel was ground into powder and placed in an alumina crucible. It was then placed in a muffle furnace for high-temperature sintering: the heating rate was 5℃ / min, the sintering temperature was 1000℃, the holding time was 5 hours, and the cooling rate was 5℃ / min. The sintered product was then ground evenly in an agate mortar to obtain manganese-based perovskite oxide electrode material powder.

[0058] (2) With Pr 0.6 Sr 0.4 Mn 1.05 O 3-δ Preparation of SOEC electrolytic cell plates for the anode:

[0059] Anode material powder and pore-forming agent, at a mass ratio of 5:1, were placed in a ball mill jar. An appropriate amount of anhydrous ethanol was added, and the jar was then placed in a ball mill for thorough ball milling. After ball milling, the jar was removed and dried in a forced-air drying oven. The resulting mixed powder was then ground uniformly using an agate mortar. A mixture of the mixed powder and a solution of turpentine percolate and ethyl cellulose (at a mass ratio of turpentine percolate to ethyl cellulose of 15:1) was placed in an agate mortar and ground uniformly to obtain the anode printing paste. The mixed paste was screen-printed onto a Ni-YSZ cathode support half-cell sheet coated with YSZ electrolyte and dried in an oven. This process was repeated 5 times. The prepared solid oxide electrolytic cell sheet was then placed in a muffle furnace for high-temperature sintering at a heating rate of 5℃ / min, a holding temperature of 1100℃ for 5 hours, and a cooling rate of 5℃ / min. After sintering is completed, the solid oxide electrolytic cell sheet loaded with manganese-based perovskite oxide anode can be obtained.

[0060] (3) Electrochemical testing process of electrolytic cell plates and method of methane oxidation coupled with carbon dioxide reduction reaction:

[0061] The electrolytic cell is installed on the electrolytic test stand. Conductive silver paste is evenly applied to both sides of the electrolytic cell sheet, and a silver mesh is used as a current collector.

[0062] At 850℃, cathode activation is first performed by introducing a hydrogen-argon mixture into the cathode, with a hydrogen volume fraction of 25%, and introducing air into the anode. The potential difference between the two electrodes of the electrolytic cell is measured using an electrochemical workstation. When the potential difference is greater than 1.2V, the cathode activation is considered complete.

[0063] Subsequently, the hydrogen-argon mixture was stopped from being introduced into the cathode, and a carbon dioxide-hydrogen mixture, with a carbon dioxide volume fraction of 75%, was introduced. Air was stopped from being introduced into the anode and replaced with nitrogen. The potential difference between the two electrodes of the electrolytic cell was monitored using an electrochemical workstation. Once the potential difference stabilized, electrolysis testing began. A constant current of 100mA was used to monitor the potential difference across the electrolytic cell; this is the operating voltage (potential A) for the electrolysis of carbon dioxide by the electrolytic cell plates.

[0064] After the test was completed, the anode gas was changed from nitrogen to methane. The potential difference between the two electrodes of the electrolytic cell was monitored using an electrochemical workstation. Once the potential difference stabilized, the electrolysis test was started. A constant current of 100mA was used for testing, and the potential difference across the electrolytic cell was monitored. This potential difference is the working voltage for the electrolytic cell plate to electrolyze carbon dioxide coupled with methane oxidation, denoted as potential B.

[0065] Gas chromatography was used to monitor the concentrations of olefins, alkanes, carbon dioxide, carbon monoxide, and hydrogen in the anode outlet gas.

[0066] The method for calculating the selectivity of ethane and ethylene is as follows:

[0067]

[0068] The relevant test results are shown in Table 1.

[0069] Example 2

[0070] Referring to Example 1, this invention provides a method for preparing a manganese-based perovskite oxide anode material, as well as the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and a method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this example has the chemical formula Sm 0.6 Sr 0.4 Mn 1.05 O 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with samarium nitrate hexahydrate, and everything else was the same as in Example 1.

[0071] Example 3

[0072] Referring to Example 1, this invention provides a method for preparing a manganese-based perovskite oxide anode material, as well as the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and a method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this example has the chemical formula Pr. 0.6 Sr 0.4 Mn 0.95 O 3-δ Everything else is the same as in Example 1.

[0073] Example 4

[0074] Referring to Example 1, this invention provides a method for preparing a manganese-based perovskite oxide anode material, as well as the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and a method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this example has the chemical formula Sm 0.6 Sr 0.4 Mn 0.95 O 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with samarium nitrate hexahydrate, and everything else was the same as in Example 1.

[0075] Example 5

[0076] Referring to Example 1, this invention provides a method for preparing a manganese-based perovskite oxide anode material, as well as the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and a method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this example has the chemical formula Pr.0.6 Sr 0.4 MnO 3-δ During the synthesis process, a 50 wt% aqueous solution of manganese nitrate was added according to the stoichiometry of manganese, and the rest was the same as in Example 1.

[0077] Example 6

[0078] Referring to Example 1, this invention provides a method for preparing a manganese-based perovskite oxide anode material, as well as the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and a method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this example has the chemical formula Sm 0.6 Sr 0.4 MnO 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with samarium nitrate hexahydrate. During the synthesis process, 50 wt% manganese nitrate aqueous solution was added according to the stoichiometry of manganese. Other aspects were the same as in Example 1.

[0079] Comparative Example 1

[0080] Referring to Example 1, a method for preparing a manganese-based perovskite oxide anode material is provided, along with the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and the method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this comparative example does not undergo stoichiometric control of manganese; its chemical formula is La. 0.6 Sr 0.4 MnO 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with lanthanum nitrate hexahydrate, and 50 wt% manganese nitrate aqueous solution was added according to the stoichiometry of manganese. Other aspects were the same as in Example 1.

[0081] Comparative Example 2

[0082] Referring to Example 1, a method for preparing a manganese-based perovskite oxide anode material is provided, along with the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and the method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this comparative example has the chemical formula La. 0.6 Sr 0.4 Mn 1.05 O 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with lanthanum nitrate hexahydrate, and everything else was the same as in Example 1.

[0083] Comparative Example 3

[0084] Referring to Example 1, a method for preparing a manganese-based perovskite oxide anode material is provided, along with the preparation of an SOEC electrolytic cell using this material as the anode, the electrochemical testing process of the electrolytic cell sheet, and the method for methane oxidation coupled with carbon dioxide reduction. The difference from Example 1 is that the manganese-based perovskite oxide anode material synthesized in this comparative example has the chemical formula La. 0.6 Sr 0.4 Mn 0.95 O 3-δ In the synthesis process, praseodymium nitrate hexahydrate was replaced with lanthanum nitrate hexahydrate, and everything else was the same as in Example 1.

[0085] Table 1

[0086] Example Chemical formula Potential A Potential B Ethane-ethylene selectivity Example 1 <![CDATA[Pr 0.6 Sr. 0.4 Mn 1.05 O 3-δ ]]> 1.72V 1.05V 35.00％ Example 2 <![CDATA[Sm 0.6 Sr. 0.4 Mn 1.05 O 3-δ ]]> 1.23V 1.15V - Example 3 <![CDATA[Pr 0.6 Sr. 0.4 Mn 0.95 O 3-δ ]]> 1.69V 0.84V 25.00％ Example 4 <![CDATA[Sm 0.6 Sr. 0.4 Mn 0.95 O 3-δ ]]> 1.04V 0.97V - Example 5 <![CDATA[Pr 0.6 Sr 0.4 MnO 3-δ ]]> 1.68V 1.00V 31.30％ Example 6 <![CDATA[Sm 0.6 Sr 0.4 MnO 3-δ ]]> 1.14V 1.10V 22.90％ Comparative Example 1 <![CDATA[La 0.6 Sr 0.4 MnO 3-δ ]]> 1.10V 1.10V 20.80％ Comparative Example 2 <![CDATA[La 0.6 Sr. 0.4 Mn 1.05 O 3-δ ]]> 1.14V 1.14V 18.30％ Comparative Example 3 <![CDATA[La 0.6 Sr. 0.4 Mn 0.95 O 3-δ ]]> 1.05V 0.98V 7.20％

[0087] As can be seen from Table 1, potential B is significantly lower than potential A. This indicates that the solid oxide electrolytic cell anode material of the present invention can reduce the potential during the coupling of carbon dioxide to methane to produce ethylene and ethane. In its application as a solid oxide electrolytic cell anode material for the coupling of carbon dioxide to methane to produce ethylene and ethane, it has achieved unexpected technical effects.

[0088] The lower the potential B during the coupling of methane to ethylene and ethane via carbon dioxide oxidation, the lower the power consumption of the electrolyzer at the same current density, and the better the economic efficiency of the electrolyzer. Ethane-ethylene selectivity is a key indicator for electrochemical methane oxidative coupling; better ethane-ethylene selectivity results in better electrolyzer economic efficiency.

[0089] As can be seen from Table 1, by comparing the embodiments of the present invention and the comparative examples, Ln 0.6 Sr 0.4 Mn 1+x O 3-δ Replacing La with Pr and Sm in rare earth elements can effectively improve the selectivity of ethane and ethylene, achieving unexpected technical results.

[0090] Comparison of Examples 1, 3, 5, and 6 further demonstrates that when Ln is Pr, the selectivity of ethane and ethylene can be further improved.

[0091] Comparing Examples 1, 3, and 5 of this invention, it can be seen that Pr can be reduced by adjusting the stoichiometry of manganese. 0.6 Sr 0.4 MnO 3-δ The potential B in Pr 0.6 Sr 0.4 Mn 1+x O 3-δIn this system, by increasing the stoichiometry of manganese to 1.05, the selectivity of ethane and ethylene can be improved while the operating potential of the electrolytic cell can be reduced, thereby further improving the economy of the electrolytic cell and achieving unexpected technical effects.

[0092] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

[0093] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0094] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0095] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0096] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0097] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0098] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A solid oxide electrolytic cell anode material, wherein the anode material has the general chemical formula Ln 0.6 Sr 0.4 Mn 1+x O 3-δ , where x is -0.05 to 0.05, Ln is one of Pr and Sm; δ represents the non-stoichiometric ratio of oxygen in the material.

2. The solid oxide electrolytic cell anode material according to claim 1, characterized in that: Ln is Sm, and x is 0 to 0.05, or Ln is Pr, and x is -0.05 to 0.05; preferably, Ln is Pr, and x is 0 to 0.

05.

3. The solid oxide electrolytic cell anode material according to claim 1, characterized in that: The anode material of the solid oxide electrolytic cell is a perovskite oxide; preferably, it is a perovskite oxide. The solid oxide electrolytic cell anode material is prepared by using Ln element source, Sr element source, and Mn element source in accordance with Ln 0.6 Sr 0.4 Mn 1+x O 3-δ The stoichiometric ratio is prepared by at least one of the following methods: sol-gel method, co-precipitation, solid-phase method, and low-temperature self-propagating combustion method; preferably, it is prepared by the gel method.

4. A method for preparing a solid oxide electrolytic cell anode material according to any one of claims 1-3, comprising following the steps of Ln 0.6 Sr 0.4 Mn 1+x O 3-δ The Ln, Sr, and Mn element sources are mixed with optional citric acid and glucose in a stoichiometric ratio, with the amounts of citric acid and glucose not both being 0. The mixture is heated to form a wet gel, which is then foamed, dried, and sintered to obtain the solid oxide electrolytic cell anode material.

5. The solid oxide electrolytic cell anode material according to claim 4, characterized in that: The Ln element source is a soluble metal salt of Ln, preferably a nitrate; and / or, The Sr source is a soluble metal salt of Sr, preferably strontium nitrate; and / or, The Mn element source is a soluble metal salt of Mn, preferably manganese nitrate; and / or, The ratio of the amount of citric acid and glucose used to the total amount of the metal element source is (0-6):1, preferably (0.5-2):1, wherein the total amount of the metal element source is equal to the sum of the total amounts of the Ln, Sr, and Mn element sources in terms of metal elements; and / or, The conditions for foaming and drying include: a temperature of 100-270℃, and / or a time of 1-4 hours; and / or, The sintering conditions include: a heating rate of 1-10℃ / min, and / or a sintering holding temperature of 850-1350℃ and a holding time of 1-10h, and / or a cooling rate of 1-10℃ / min; and / or, This also includes pulverizing the foamed and dried material before sintering; and / or, It also includes pulverizing the sintered material after sintering to obtain powdered solid oxide electrolytic cell anode material.

6. A solid oxide electrolytic cell, comprising an anode, an electrolyte, and a cathode, wherein the electrolyte is a supported oxygen ion-conducting electrolyte used to support the anode and cathode. The anode contains the solid oxide electrolytic cell anode material according to any one of claims 1-3 or the solid oxide electrolytic cell anode material obtained by the preparation method according to claim 4 or 5.

7. The solid oxide electrolytic cell according to claim 6, characterized in that: The electrolyte is at least one of zirconium oxide YSZ type electrolyte and lanthanum strontium gallium magnesium LSGM type electrolyte; and / or, the cathode is at least one of yttrium-coated zirconium oxide YSZ electrolyte material, nickel oxide-YSZ, strontium iron molybdenum oxide, and the same material as the anode material; preferably, The cathode and the electrolyte are derived from solid oxide half-cells. More preferably, the solid oxide half-cell is at least one of the following: a nickel-YSZ cathode support half-cell coated with yttrium zirconium oxide YSZ electrolyte; a YSZ electrolyte support half-cell with nickel oxide-YSZ as the cathode; a YSZ support half-cell with strontium iron molybdenum oxide as the cathode; a lanthanum-strontium gallium magnesium LSGM electrolyte support half-cell with strontium iron molybdenum oxide as the cathode; a YSZ support half-cell with the same material as the anode as the cathode; and a lanthanum-strontium gallium magnesium LSGM electrolyte support half-cell with the same material as the anode as the cathode.

8. A method for preparing a solid oxide electrolytic cell according to claim 6 or 7, characterized in that, include: The process involves mixing a mixture containing the solid oxide electrolytic cell anode material and an optional pore-forming agent with a binder to obtain an anode printing paste, coating the anode printing paste onto the anode side of the electrolyte, and then drying and sintering to obtain the electrolytic cell anode; preferably, The electrolyte is derived from a solid oxide half-cell cell having a cathode and an electrolyte. In this case, the anode printing paste is coated onto the anode side of the electrolyte, and after drying and sintering, a solid oxide electrolytic cell is obtained.

9. The preparation method according to claim 8, characterized in that: The pore-forming agent is selected from at least one of starch, graphite, and PMMA powder; and / or, The amount of the pore-forming agent added is 0-25 wt% of the mass of the solid oxide electrolytic cell anode material; and / or, The binder is turpentine percolate and ethyl cellulose, preferably with a mass ratio of turpentine percolate to ethyl cellulose of (15-9):1; and / or, The mass ratio of the mixture to the binder is (0.1–1.5):1, preferably (0.5–1):1; and / or, Drying conditions include: a temperature of 65–85°C, and / or a time of 5–10 min; and / or, The sintering conditions include: a heating rate of 1–10 °C / min during sintering, a holding temperature of 1000–1150 °C, a holding time of 2–5 h, and a cooling rate of 1–10 °C / min.

10. The application of the solid oxide electrolytic cell anode material of any one of claims 1-3, or the solid oxide electrolytic cell anode material obtained by the preparation method of claim 4 or 5, or the solid oxide electrolytic cell of claim 6 or 7, or the solid oxide electrolytic cell prepared by the preparation method of claim 8 or 9, in the production of hydrocarbon compounds by coupling methane with carbon dioxide oxidation, wherein the hydrocarbon compounds preferably include ethylene and ethane.

11. The application according to claim 10, characterized in that, include: At 750-850℃, the cathode side of the solid oxide electrolytic cell is placed in an atmosphere containing carbon dioxide, and the anode side is placed in a methane atmosphere. An external voltage is applied between the cathode and the anode to carry out a methane oxidative coupling reaction at the solid oxide anode to obtain a gas containing ethylene and ethane. Preferably, the applied voltage is 0.1-2V, more preferably 0.9-1.2V; and / or, Preferably, the atmosphere containing carbon dioxide is a carbon dioxide-hydrogen mixture atmosphere, and the volume fraction of carbon dioxide is preferably 50%-100%, more preferably 70%-95%.

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