Composition with activated methane function, electrochemical reactor and its applications and method for methane oxidation coupling

Abstract

The present application relates to solid oxide cell, electrolytic cell technical field, disclose the composition with the function of activating methane and electrochemical reactor and application and the method for methane oxidation coupling, the composition includes component A, component B and component C;Wherein, the component A includes manganese oxide, tungsten oxygen acid alkali metal salt and optional cerium oxide;The component B includes yttria stabilized zirconia and / or gadolinium oxide doped ceria;The component C includes perovskite;The mass ratio of component A, component B and component C is 1:1-20:1-50.The electrode prepared by using the composition shows excellent electrochemical performance and methane oxidation coupling performance, which provides support for realizing efficient electrochemical conversion of methane.

Description

Technical Field

[0001] This invention relates to the fields of solid oxide batteries and electrolytic cells, specifically to a composition with methane activation function, an electrochemical reactor, its application, and a method for methane oxidative coupling. Background Technology

[0002] With breakthroughs in shale gas extraction technology, global proven natural gas reserves are continuously increasing, and the direct production of high-value-added chemicals from methane has become a research hotspot in recent years. Methane oxidative coupling, targeting the important chemical ethylene as a product, is one such emerging technology. However, traditional high-temperature thermochemical methane oxidative coupling reactions require the simultaneous introduction of methane and oxygen, which poses certain safety risks and hinders its large-scale application. Furthermore, the oxygen required for the reaction needs to be separated from the air, increasing additional costs. Using a solid oxide electrolysis cell for high-temperature electrochemical methane oxidative coupling is a feasible solution, generating oxygen ions (O3) through the reduction of oxides at the cathode. 2- Methane is transferred to the anode side via the electrolyte membrane and oxidized to form active oxygen species, thereby activating methane. Thus, methane and oxygen are separated on both sides and do not mix directly, avoiding potential explosion risks. The required oxygen source can be obtained by directly reducing oxygen in the air at the cathode without separation. Simultaneously, the reaction can be easily controlled by adjusting the voltage. However, the design and development of electrode catalysts for electrochemical methane oxidative coupling is a significant challenge because it requires ionic and electronic conductivity, oxygen evolution capacity, and methane activation capacity, and currently, few materials meet these requirements. Traditional thermal catalyst materials are mainly metal oxides or Ce-Mn-Na2WO4@SiO2, which generally lack electronic conductivity, leading to excessively high impedance in the electrolyzer and making them unsuitable for direct application as electrodes in solid oxide electrolyzers. Furthermore, common oxygen evolution anode materials in solid oxide electrolyzers, such as LSCF(La... 0.6 Sr 0.4 Cr 0.5 Fe 0.5 O 3-δ While electrodes such as [insert electrodes here] have good electronic conductivity and oxygen evolution capacity, their methane activation performance is poor. Therefore, developing electrodes suitable for high-temperature electrochemical methane oxidative coupling remains a significant challenge.

[0003] Prior Art 1: CN202311573878.X A Sr2TiFeO6-based perovskite electrode material for solid oxide electrolysis cells, its preparation method, and its application. This invention discloses a Sr2TiFeO6-based perovskite electrode material for solid oxide electrolysis cells, the chemical formula of which is Sr2Ti. 1-x FeM x O 6-δM = Mg, Cu, Cr, or Mn, where x is the element doping content, 0 ≤ x ≤ 0.3; δ is the oxygen vacancy content in the material, and 6-δ is the oxygen content in the material lattice. This perovskite-based electrode material exhibits excellent electrochemical performance and can effectively improve the CO2 electrolysis efficiency of solid oxide electrolyzers. However, there are no reports on its application in high-temperature electrochemical methane oxidative coupling.

[0004] Prior Art 2: CN202410537943.1 A method for preparing nickel-supported gadolinium-doped cerium oxide and its application. This invention discloses a method for preparing nickel-supported gadolinium-doped cerium oxide and its application in anode materials for the electrochemical oxidation of methane in solid oxide electrolytic cells. The chemical composition of this anode material for the electrochemical oxidation of methane in solid oxide electrolytic cells is nickel-supported gadolinium-doped cerium oxide powder, wherein the powder has the general formula x wt% Ni-Ce y Gd (1-y) O 2-δ Where 0.5≤y≤0.9. The anode material of this invention has good ionic conductivity and certain methane catalytic activity, but there are no reports on the use of this electrode material for electrochemical methane oxidative coupling.

[0005] Prior Art 3: CN202210376741.4 Solid Oxide Battery Based on LSCF Anode, its Preparation Method and its Application in the Oxidative Coupling of Methane to Ethylene and Ethane. This invention discloses a solid oxide battery based on an LSCF anode and a method for secondary enhanced electrochemical oxidative coupling of methane to ethylene and ethane. The LSCF anode material is La, which is formed by the desolvation of iron. 0.75 Sr 0.25 Cr 0.5 Fe 0.5+x O 3-δ A metal oxide interface was constructed on the substrate. This invention exhibits high electrochemical reactivity and resistance to carbon deposition, and can also convert methane into products such as ethane and ethylene; however, the selectivity for these C2 products is less than 20%.

[0006] Based on the above analysis, the problems and shortcomings of the existing technology are as follows: While many electrode materials for solid oxide electrolyzers reported in existing patents perform well in high-temperature CO2 electrolysis or oxygen evolution reaction applications, there are few reports of their application in high-temperature electrochemical methane oxidative coupling, or the C2 product selectivity of the anode materials used is extremely low. Therefore, there is a need for a composition with methane-activating function, an electrochemical reactor, its application, and a method for methane oxidative coupling. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of high electrode electrochemical impedance and poor electrochemical methane activation performance in the prior art, and to provide a composition with methane activation function, an electrochemical reactor, its application, and a method for methane oxidative coupling.

[0008] To achieve the above objectives, a first aspect of the present invention provides a composition having a methane-activating function, characterized in that the composition comprises component A, component B and component C; wherein, component A comprises manganese oxide, tungsten oxoacid salt and optionally cerium oxide; component B comprises yttrium-stabilized zirconium oxide and / or gadolinium-doped cerium oxide; component C comprises perovskite; and the mass ratio of component A, component B and component C is 1:1-20:1-50.

[0009] The second aspect of the present invention provides the use of the composition described in the first aspect of the present invention in an electrochemical reactor.

[0010] A third aspect of the present invention provides an electrochemical reactor, characterized in that the electrochemical reactor includes an anode and a cathode and an electrolyte layer disposed between the anode and the cathode, the anode including component A, component B and component C, and the cathode including a cathode support and a cathode active component attached to the cathode support.

[0011] The definitions of component A, component B and component C are the same as those described in the first aspect of the present invention.

[0012] The fourth aspect of the present invention provides the application of the electrochemical reactor described in the third aspect of the present invention in methane oxidative coupling.

[0013] The fifth aspect of the present invention provides a method for methane oxidative coupling, characterized in that the method includes, under electrolytic reaction conditions, introducing a methane-containing gas into the anode of the electrochemical reactor described in the third aspect of the present invention, introducing a carbon dioxide-containing gas into the cathode, and collecting the anode outlet gas.

[0014] Through the above technical solution, the beneficial effects of the present invention are at least as follows: The present invention discloses a type of electrode for electrochemical methane oxidative coupling in SOEC and its preparation method, which effectively solves the problems of insufficient conductivity of traditional thermal catalyst materials in electrochemical systems and poor methane activation ability of general SOEC oxygen evolution materials. It can effectively meet the requirements of ionic and electronic conductivity, oxygen evolution ability and methane activation ability of electrochemical methane oxidative coupling electrodes, exhibiting excellent electrochemical performance and methane oxidative coupling performance, and providing support for the realization of efficient electrochemical conversion of methane. Attached Figure Description

[0015] Figure 1 This is a scanning electron microscope (SEM) image of the anode material in Embodiment 1 of the present invention;

[0016] Figure 2 This is a scanning electron microscope (SEM) image of the anode material in Embodiment 2 of the present invention;

[0017] Figure 3 This is a scanning electron microscope (SEM) image of the anode material in Example 3 of the present invention;

[0018] Figure 4 The electrochemical impedance test results of the electrode prepared in Example 1 of the present invention at 850°C in a methane / carbon dioxide atmosphere;

[0019] Figure 5 Current density-voltage curve of the electrode prepared in Example 1 of the present invention at 850°C in a methane / carbon dioxide atmosphere;

[0020] Figure 6 The electrode prepared for Example 1 of this invention was subjected to a temperature of 850°C and a current of 200 mA cm⁻¹. -2 Voltage-time test curves of constant current electrolysis of methane at a given current density. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. 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.

[0022] As previously stated, a first aspect of the present invention provides a composition having a methane-activating function, characterized in that the composition comprises component A, component B and component C; wherein, component A comprises an oxide of manganese, an oxoacid salt of tungsten and optionally an oxide of cerium; component B comprises yttrium-stabilized zirconium oxide and / or gadolinium-doped cerium oxide; component C comprises perovskite; and the mass ratio of component A, component B and component C is 1:1-20:1-50.

[0023] In this invention, yttrium-stabilized zirconium oxide and gadolinium-doped cerium oxide can be various commercially available products. For example, the weight ratio of yttrium oxide to zirconium oxide can be 3-10:100, specifically products from Tosoh Corporation of Japan, such as the 8Y, 8YS, and 8YSB grades. The weight ratio of gadolinium oxide to cerium oxide can also be 3-10:100, specifically GDC products from Sofcman Corporation. 10 GDC 20 Products with a brand name.

[0024] In some embodiments of the present invention, preferably, the manganese oxide is selected from at least one of manganese oxide, manganese dioxide, and manganese trioxide.

[0025] In some embodiments of the present invention, preferably, the oxoacid salt of tungsten is selected from at least one of alkali metal tungstate, alkaline earth metal tungstate, and ammonium tungstate.

[0026] In some embodiments of the present invention, preferably, the cerium oxide is selected from cerium trioxide, cerium dioxide, and Ce. n O 2n-2 At least one of the following, wherein n is selected from 4, 6, 7, 9, 10 or 11.

[0027] In some embodiments of the present invention, preferably, the perovskite structure is selected from LSM (composition La). 0.7 Sr 0.3 MnO3), LSCF (composed of La) 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ), SFMO (composed of Sr2FeMoO6) and PBSCF (composed of PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ At least one of the following.

[0028] In this invention, δ is the value required to satisfy the valence of elements other than oxygen atoms in the perovskite structure.

[0029] In some embodiments of the present invention, preferably, the mass ratio of component A, component B and component C is 1:2-15:2-35.

[0030] In some embodiments of the present invention, preferably, the manganese oxide is selected from manganese dioxide and / or manganese trioxide.

[0031] In some embodiments of the present invention, preferably, the oxoacid salt of tungsten is selected from alkali metal tungstate salts and / or ammonium tungstate, and more preferably at least one of sodium tungstate, potassium tungstate and ammonium tungstate.

[0032] In some embodiments of the present invention, preferably, the cerium oxide is selected from cerium trioxide and / or cerium dioxide.

[0033] In some embodiments of the present invention, preferably, based on the total weight of component A and component B, the content of component A is 5-50 wt%, preferably 10-25 wt%; and the content of component B is 50-95 wt%, preferably 75-90 wt%.

[0034] In this invention, the contents of component A and component B can be determined by EDS energy dispersive spectroscopy and gravimetric method, respectively.

[0035] In some embodiments of the present invention, preferably, the mass ratio of component A, component B and component C is 1:3-7:4-20.

[0036] In this invention, the mass ratio of component A, component B and component C can be obtained by EDS energy dispersive spectroscopy and weighing method.

[0037] In some embodiments of the present invention, preferably, the mass ratio of the manganese oxide, the oxoacid salt of tungsten, and the oxide of cerium is 1:0.2-5:0.2-5, more preferably 1:0.5-2:0.5-2.

[0038] In this invention, the mass ratio of the manganese oxide, the oxoacid salt of tungsten, and the oxide of cerium can be characterized by an EDS energy dispersive spectroscopy instrument.

[0039] The second aspect of the present invention provides the use of the composition described in the first aspect of the present invention in an electrochemical reactor.

[0040] A third aspect of the present invention provides an electrochemical reactor, characterized in that the electrochemical reactor includes an anode and a cathode and an electrolyte layer disposed between the anode and the cathode, the anode including component A, component B and component C, and the cathode including a cathode support and a cathode active component attached to the cathode support;

[0041] The definitions of component A, component B and component C are the same as those described in the first aspect of the present invention.

[0042] In some embodiments of the present invention, preferably, the cathode support is at least one of yttrium-stabilized zirconium oxide, gadolinium-doped cerium oxide, and lanthanum strontium gallium magnesium oxide (LSGM), and the cathode active component is selected from at least one of NiO, SFMO, and LSM, wherein the content of the cathode active component is 20-60 wt% based on the total amount of the cathode.

[0043] In some embodiments of the present invention, preferably, the electrolyte layer comprises at least one of yttrium-stabilized zirconium oxide (YSZ), gadolinium-doped cerium oxide (GDC), and lanthanum strontium gallium magnesium oxide (LSGM).

[0044] In some embodiments of the present invention, preferably, component C is located between the electrolyte layer and the complex formed by component A and component B.

[0045] In some embodiments of the present invention, preferably, the method for preparing the electrochemical reactor includes:

[0046] The electrochemical reactor is obtained by contacting the anode, which has the function of activating methane, with the electrolyte layer of the half-cell and calcining it.

[0047] In some embodiments of the present invention, preferably, the contact method includes bonding.

[0048] In some embodiments of the present invention, preferably, the adhesive used for bonding is selected from organic adhesives, preferably a terpineol solution of ethyl cellulose, more preferably a 6-8 wt% terpineol solution of ethyl cellulose.

[0049] In this invention, a half-cell refers to a structure that includes an electrolyte layer and a cathode (including a mixture of ceramic components and a cathode catalyst). Compared to the finished battery product (i.e., an electrochemical reactor), it lacks an anode portion (i.e., an anode support and an anode catalyst supported on the anode support), hence the name half-cell.

[0050] In some embodiments of the present invention, preferably, the half-cell is a NiO-YSZ|YSZ, NiO-GDC|GDC, SFMO-LSGM|LSGM or SFMO-GDC|LSGM half-cell synthesized by powder pressing and / or casting method without microchannel structure, more preferably the NiO-YSZ|YSZ and SFMO-GDC|LSGM half-cell.

[0051] In some embodiments of the present invention, preferably, the thickness of the electrolyte layer is 20-1000 micrometers, and more preferably 30-300 micrometers.

[0052] In this invention, the thickness of the electrolyte layer can be determined by scanning electron microscopy.

[0053] In some embodiments of the present invention, preferably, the calcination temperature is 800-1200℃, more preferably 850-1100℃; and the time is 2-4h, more preferably 2.5-3.5h.

[0054] In some embodiments of the present invention, preferably, the method for preparing the anode with methane-activating function includes stacking and mixing.

[0055] In some embodiments of the present invention, preferably, the method for preparing the stack includes:

[0056] (1) Mix the component C with the binder and coat it onto the electrolyte layer of the half cell. After drying, calcination is performed to obtain a half cell covered with component C.

[0057] (2) The composite formed by the components A and B is coated on the surface of component C of the half cell covered by component C in step (1), dried, and then calcined.

[0058] In some embodiments of the present invention, preferably, the mass ratio of component C to the adhesive is 1:1-10, more preferably 1:1-5.

[0059] In some embodiments of the present invention, preferably, the mass ratio of the composite to the adhesive is 1:1-10, more preferably 1:1-5.

[0060] In some embodiments of the present invention, preferably, the coating method in steps (1) and (2) is screen printing, wherein the mesh size of the screen is 200-400 mesh.

[0061] In some embodiments of the present invention, preferably, the coating and drying operations described in step (1) are repeated.

[0062] In some embodiments of the present invention, preferably, the coating and drying operations described in step (1) are repeated 1-5 times.

[0063] In some embodiments of the present invention, preferably, the calcination temperature in step (1) is 800-1100℃ and the time is 2-8h.

[0064] In some embodiments of the present invention, preferably, the coating and drying operations described in step (2) are repeated 1-3 times.

[0065] In some embodiments of the present invention, preferably, the calcination temperature in step (2) is 800-900℃ and the time is 2-8h.

[0066] In some embodiments of the present invention, preferably, the preparation method of the mixture includes:

[0067] The complex formed by the mixture of component C with components A and B is coated onto the electrolyte layer of the half-cell, dried, and calcined.

[0068] In some embodiments of the present invention, preferably, the coating method is screen printing, and the mesh size of the screen is 200-400 mesh.

[0069] In some embodiments of the present invention, preferably, the coating and drying operations are repeated.

[0070] In some embodiments of the present invention, preferably, the coating and drying operations are repeated 1-3 times.

[0071] In some embodiments of the present invention, preferably, the drying temperature is 40-90°C and the time is 0.5-18h.

[0072] In some embodiments of the present invention, preferably, the calcination temperature is 800-1100℃ and the time is 2-8h.

[0073] In some embodiments of the present invention, preferably, the preparation method of the complex formed by component A and component B includes: mixing component A and component B and then calcining them, followed by grinding to obtain the complex.

[0074] In some embodiments of the present invention, preferably, the mass ratio of component A to component B is 1:1-20, more preferably 1:3-7.

[0075] In some embodiments of the present invention, preferably, the mixing method includes mixing the oxoacid salt of tungsten, component B, manganese salt and optional cerium salt in the presence of a solvent, evaporating to dryness, and then performing a drying process.

[0076] In some embodiments of the present invention, preferably, the solvent is selected from water.

[0077] In some embodiments of the present invention, the mixing method preferably includes stirring.

[0078] In some embodiments of the present invention, preferably, the manganese salt and cerium salt are selected from nitrates.

[0079] In some embodiments of the present invention, preferably, the feeding ratio of the tungsten oxyacid salt, manganese salt and cerium salt is determined according to the mass ratio of the manganese oxide, the tungsten oxyacid salt and the cerium oxide.

[0080] In some embodiments of the present invention, preferably, the mixing temperature is 100-150°C and the time is 1-5 hours.

[0081] In some embodiments of the present invention, preferably, the evaporation temperature is 100-150°C and the time is 8-18 hours, preferably 8-12 hours.

[0082] In some embodiments of the present invention, preferably, the calcination temperature is 600-1000℃, more preferably 800-900℃; and the time is 3-10h, more preferably 3-6h.

[0083] In some embodiments of the present invention, preferably, the grinding method includes grinding with a mortar and pestle and sieving with a sieve.

[0084] In some embodiments of the present invention, preferably, the sieve is selected from a 20-80 mesh sieve, and more preferably a 40-60 mesh sieve.

[0085] The fourth aspect of the present invention provides the application of the electrochemical reactor described in the third aspect of the present invention in methane oxidative coupling.

[0086] The fifth aspect of the present invention provides a method for methane oxidative coupling, characterized in that the method includes, under electrolytic reaction conditions, introducing a methane-containing gas into the anode of the electrochemical reactor described in the third aspect of the present invention, introducing a carbon dioxide-containing gas into the cathode, and collecting the resulting C2 gas.

[0087] In some embodiments of the present invention, preferably, the electrolysis reaction conditions include a temperature of 700-850°C and a gas flow rate of 0.5-50 mL / min / cm² (calculated as methane). 2 The current density is 0-1200 mA / cm² 2 .

[0088] The present invention will be described in detail below through embodiments. In the following embodiments, the YSZ raw material is a commercially available product from TOSOH with the brand name 8YS; the GDC raw material is a product from Sofcman with the brand name GDC. 10 The raw materials are commercially available products; LSCF is a commercially available product from Sofcman; LSM is a commercially available product from Sofcman. Unless otherwise specified, all other raw materials are ordinary commercially available products.

[0089] Example 1

[0090] This embodiment provides a method for preparing an electrochemical methane oxidation coupling electrode for SOEC, wherein the mass ratio of components A, B, and C is 1:7:20, A is a mixture of CeO2, Mn2O3, and sodium tungstate in a mass ratio of 2:1:2, B is GDC powder, and C is LSM powder, including the following steps:

[0091] (1) GDC powder and ethanol were ball-milled in a planetary ball mill for 8 hours at a ratio of 1:1.

[0092] (2) Transfer the mixture of GDC and ethanol to a mortar, dry it in an oven, grind it into a fine powder, and sieve it through a 60-mesh sieve for later use;

[0093] (3) Weigh 0.32g of Na2WO4·2H2O salt and dissolve it in 20mL of deionized water. Stir until completely dissolved, then add 5g of the ball-milled GDC powder and continue stirring until a uniform suspension is formed. Add 0.23g of 50% manganese nitrate aqueous solution and stir for 5min. Then add 0.72g of Ce(NO3)3·6H2O salt and continue stirring at room temperature for 2h. Heat to 130℃ and continue stirring for 10h to evaporate to dryness. Transfer to an oven at 60℃ and continue drying for 12h.

[0094] (4) After the dried powder is crushed, it is transferred to a crucible and calcined in a muffle furnace at 850°C in an air atmosphere for 3 hours. The resulting powder is then ground into fine powder using a mortar and sieved through a 60-mesh sieve to obtain a composite of A and B with a mass ratio of 1:7.

[0095] (5) Grind and mix the A and B complexes with LSM powder at a mass ratio of 1:2.5 until uniform, and prepare an anode slurry with a total mass to organic binder mass ratio of 1:1.

[0096] (6) The anode paste is coated on the electrolyte layer surface of the NiO-YSZ|YSZ semi-electrolytic cell sheet by screen printing. The mesh size of the screen used is 200 mesh, and the number of printing layers is 3. After printing one layer, the electrolytic cell sheet is placed in an oven to dry before the next printing begins.

[0097] (7) Sinter the electrolytic cell sheet at 850°C in air atmosphere for 3 hours.

[0098] The anode morphology in the electrode is as follows: Figure 1 The scanning electron microscope image is shown. Electrochemical impedance spectroscopy, voltage-current plotting, and galvanostatic electrolysis plotting were performed on the electrode under a methane atmosphere. The results are shown below. Figures 4-6 As shown. Figure 4 In this context, the ohmic resistance of the electrode is 0.2 Ω·cm. 2 The polarization impedance is only 0.3 Ω·cm 2 This indicates that it has excellent electrochemical performance; Figure 5 In this process, the electrode exhibits a current density exceeding 0.5 A·cm² at a voltage of 2V. -2 This indicates that it has excellent electrochemical activity; Figure 6 In the electrolysis process, the electrode did not show a significant voltage rise during the electrolysis process of more than 5000s, indicating that its electrolysis stability is excellent.

[0099] Example 2

[0100] The difference from Example 1 is that the electrochemical reactor for SOEC prepared in this example has a mass ratio of A, B, and C of 1:3:10. A is a mixture of CeO2, Mn2O3, and sodium tungstate in a mass ratio of 2:1:2. B is GDC, and C is LSM. The sintering temperature of the LSM paste after screen printing is 1000℃. The composite formed by A and B and component C are stacked to prepare the electrode. Component C is printed in 3 layers, and the A and B composite is printed in one layer. The semi-electrolytic cell used is an SFMO-GDC|LSGM semi-electrolytic cell. The anode morphology in the electrode is as follows. Figure 2 The scanning electron microscope image is shown.

[0101] Example 3

[0102] The difference from Example 1 is that an electrochemical reactor for SOEC was prepared, with the mass ratio of A, B, and C being 1:3:4. A is a mixture of CeO2, Mn2O3, and sodium tungstate in a mass ratio of 2:1:2. B is YSZ, and C is LSCF. The electrode paste is screen-printed in 5 layers, and the calcination temperature is 1100℃. The anode morphology in the electrode is as follows... Figure 3 The scanning electron microscope image is shown.

[0103] Example 4

[0104] The difference from Example 1 is that no CeO2 component is added in A, resulting in an electrochemical reactor.

[0105] Example 5

[0106] The difference from Example 1 is that SrTiO3 is used instead of LSM.

[0107] Example 6

[0108] The difference from Example 1 is that the mass ratio of components A, B, and C is 1:7:50.

[0109] Example 7

[0110] The difference from Example 1 is that the mass ratio of A to B is 1:20.

[0111] Comparative Example 1

[0112] The difference from Example 1 is that it does not contain component C.

[0113] Comparative Example 2

[0114] The difference from Example 1 is that it does not contain components A and B.

[0115] Comparative Example 3

[0116] The difference from Example 1 is that it does not contain component B.

[0117] Comparative Example 4

[0118] The difference from Example 1 is that it does not contain component A.

[0119] Comparative Example 5

[0120] The difference from Example 1 is that component B (GDC) is replaced with TiO2.

[0121] Comparative Example 6

[0122] The difference from Example 1 is that the mass ratio of components A, B, and C is 1:7:100.

[0123] Test case

[0124] 1. At 850℃, 20 mL of gas is introduced into the anode. -1 Methane, 5 mL is passed through the cathode for min -1 Hydrogen and 15 mL min -1 The electrochemical impedance spectroscopy of the electrochemical reactors prepared in each example and comparative example was performed using CO2, and the test results are shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] 2. At 850℃, 20 mL of gas is introduced into the anode. -1 Methane, 5 mL is passed through the cathode for min -1 Hydrogen and 15 mL min -1 CO2 was produced using a constant current electrolysis method at 200 mA cm⁻¹. -2 Electrolysis tests were conducted on the electrochemical reactors prepared in each embodiment and comparative example at a current density. The anode outlet gas was collected by online chromatography to analyze the C2 product selectivity and the methane conversion rate. The test results are shown in Table 2.

[0129] Table 2

[0130]

[0131]

[0132] Combining Tables 1 and 2, it can be seen that the designed electrochemical methane oxidative coupling electrodes for SOEC (Examples 1-3) possess low electrochemical impedance and high C2 product selectivity, indicating that the designed electrodes exhibit excellent electrochemical methane oxidative coupling performance. In contrast, the electrode without an oxygen evolution conductive layer (Comparative Example 1) has extremely high electrochemical impedance, making electrochemical testing impossible; while the electrode without a composite active component layer (Comparative Example 2) has low electrochemical impedance, but extremely poor C2 product selectivity (existing technology, C2); and the C2 product selectivity is also poor when the active component is directly loaded onto the oxygen evolution conductive material without a support (Comparative Example 3). These comparative examples further demonstrate that the designed electrodes possess both excellent electrochemical performance and methane oxidative coupling performance.

[0133] As can be seen from the results in Tables 1 and 2, compared with the comparative examples, the compositions prepared using the technical solutions of the present invention have beneficial effects such as low electrode electrochemical impedance and good electrochemical methane activation performance.

[0134] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composition having the function of activating methane, characterized in that, The composition comprises component A, component B, and component C; wherein component A comprises manganese oxide, tungsten oxoacid salt, and optionally cerium oxide; component B comprises yttrium-stabilized zirconium oxide and / or gadolinium-doped cerium oxide; and component C comprises perovskite. The mass ratio of component A, component B and component C is 1:1-20:1-50.

2. The composition according to claim 1, wherein, The manganese oxide is selected from at least one of manganese oxide, manganese dioxide, and manganese trioxide; And / or, the oxyacid salt of tungsten is selected from at least one of alkali metal tungstate, alkaline earth metal tungstate, and ammonium tungstate; And / or, the cerium oxide is selected from cerium trioxide, cerium dioxide, and Ce. n O 2n-2 At least one of the following, wherein n is selected from 4, 6, 7, 9, 10 or 11; And / or, the perovskite-structured compound is selected from at least one of LSM, LSCF, SFMO and PBSCF; And / or, the mass ratio of component A, component B and component C is 1:2-15:2-35.

3. The composition according to claim 1 or 2, wherein, The manganese oxide is selected from manganese dioxide and / or manganese trioxide; And / or, the oxyacid salt of tungsten is selected from alkali metal tungstate salts and / or ammonium tungstate, preferably at least one of sodium tungstate, potassium tungstate and ammonium tungstate; And / or, the oxide of cerium is selected from cerium trioxide and / or cerium dioxide; And / or, the perovskite-structured compounds are selected from LSM and / or LSCF; And / or, the mass ratio of component A, component B and component C is 1:3-7:4-20.

4. The composition according to any one of claims 1-3, wherein, The mass ratio of the manganese oxide, the oxoacid salt of tungsten, and the oxide of cerium is 1:0.2-5:0.2-5, preferably 1:0.5-2:0.5-2.

5. The use of the composition according to any one of claims 1-4 in an electrochemical reactor.

6. An electrochemical reactor, characterized in that, The electrochemical reactor includes an anode and a cathode, as well as an electrolyte layer placed between the anode and the cathode. The anode includes component A, component B, and component C, and the cathode includes a cathode support and a cathode active component attached to the cathode support. The definitions of components A, B, and C are identical to those in any one of claims 1-4.

7. The electrochemical reactor according to claim 6, wherein, The cathode support is at least one of yttrium-stabilized zirconium oxide, gadolinium-doped cerium oxide, and lanthanum strontium gallium magnesium oxide (LSGM). The cathode active component is selected from at least one of NiO, SFMO, and LSM. The content of the cathode active component is 20-60 wt%, based on the total amount of the cathode.

8. The electrochemical reactor according to claim 6 or 7, wherein, The electrolyte layer comprises at least one of yttrium-stabilized zirconium oxide, gadolinium-doped cerium oxide, and lanthanum-strontium-gallium-magnesium oxide.

9. The electrochemical reactor according to any one of claims 6-8, wherein, Component C is located between the electrolyte layer and the complex formed by component A and component B.

10. The use of the composition according to any one of claims 1-4 or the electrochemical reactor according to any one of claims 6-9 in methane oxidative coupling.

11. A method for oxidative coupling of methane, characterized in that, The method includes, under electrolytic reaction conditions, introducing a methane-containing gas into the anode of the electrochemical reactor according to any one of claims 6-9, introducing a carbon dioxide-containing gas into the cathode, and collecting the resulting C2 gas.

12. The method according to claim 11, wherein, The electrolysis reaction conditions include a temperature of 700-850℃ and a gas flow rate of 0.1-50 mL / min / cm³ (based on methane). 2 The current density is 0-1200 mA / cm² 2 .

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