A gas phase migration method for loading nanoparticulate solid oxide electrolyser hydrogen electrode materials, methods of preparation and use

Abstract

The present invention relates to a kind of gas phase migration method loaded nanoparticle solid oxide electrolysis cell (SOEC) hydrogen electrode material, preparation method and use. Cu-La 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3‑δ (LSTF), wherein δ is the content of oxygen vacancy. Compared with other traditional physical loading methods, Cu can be uniformly dispersed in LSTF carrier to promote the exposure of active sites. The SOEC with Cu-LSTF hydrogen electrode is tested, and the hydrogen electrode which can be easily prepared has excellent CO2 reduction capacity compared with traditional solid oxide electrolysis cell hydrogen electrode. The new hydrogen electrode material shows excellent electrochemical performance and excellent stability in long-term test.

Description

Technical Field

[0001] This invention relates to a simple vapor-phase migration method for loading nanoparticles onto a solid oxide electrolytic cell hydrogen electrode material, its preparation method, and its applications. Specifically, it relates to the perovskite material Cu-La. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ The preparation method and application of composite anodes belong to the field of solid oxide electrolytic cell electrode material technology. Background Technology

[0002] In recent years, with the continuous rise in global temperatures and the escalating energy crisis, it has become crucial to reduce emissions of carbon dioxide and other pollutants and establish a system for the most efficient use of energy. Currently, the application of clean energy technologies is growing rapidly. Utilizing surplus electricity to electrolyze CO2 can convert it into fuels and chemicals, contributing to the recycling of CO2 resources.

[0003] Solid oxide electrolyzers (SOECs) are a highly efficient energy conversion technology capable of converting electrical and thermal energy into chemical energy at high temperatures, showing particular potential in water electrolysis and direct CO2 electrolysis. Among various electrochemical technologies, high-temperature CO2 electrolysis via SOECs offers significant advantages over others, such as high current density, strong stability, and near-100% Faraday efficiency, making it more suitable for practical applications. An SOEC single cell consists of a hydrogen electrode, an oxygen electrode, and an electrolyte. Both the hydrogen and oxygen electrodes are porous materials, facilitating gas transport. The electrolyte is a dense material to prevent electron transport from causing short circuits. During the high-temperature CO2 electrolysis process, CO2 is reduced at the hydrogen electrode to form CO and O. 2- O 2- O2 is formed by passing through the electrolyte to the anode side. Therefore, research on SOEC mainly focuses on improving the catalytic activity, stability, and cost reduction of hydrogen electrode materials. Traditional SOEC hydrogen electrode materials typically employ Ni-based cermet composite electrodes, but these materials are prone to nickel metal agglomeration, carbon deposition, and poisoning at high temperatures, leading to performance degradation. To address these issues, researchers have explored various novel cathode materials. Perovskite oxides have attracted attention due to their unique structure and tunable chemical properties. By adjusting the chemical composition and microstructure, the adsorption capacity and catalytic activity for CO2 can be improved, thereby enhancing electrolysis performance and stability.

[0004] However, the relatively poor CO2 reduction reaction (CO2RR) activity of perovskite materials is a major problem they face, and their lifespan and stability at high temperatures are also major bottlenecks for commercialization. Therefore, developing high-performance bifunctional hydrogen electrodes with high electrocatalytic activity and stability is of great significance for SOEC CO2 electrolysis. The interface between metal nanoparticles (NPs) and transition metal oxide supports is often considered the active site for many important catalytic reactions. Maximizing the metal-oxide interface sites is an effective way to improve catalytic performance. In-situ dissolution through a reducing atmosphere can provide excellent catalytic activity and can also form a unique nanoparticle-perovskite interface with high resistance to aggregation. However, during the reduction process, the dissolution of B-site reducible cations inevitably leaves many B-site vacancies in the perovskite bulk phase, which is detrimental to the long-term operation of the electrolyzer and greatly affects its stability. Therefore, new strategies are urgently needed to improve the stability of dissolved metal particles under long-term operation while promoting the precipitation of nanoparticles. Summary of the Invention

[0005] To address the issues of low catalytic activity and poor operational stability of perovskite materials as hydrogen electrode materials in SOEC CO2 electrolysis, this invention employs a simple high-temperature gas migration strategy to directly deposit powdered materials onto the existing perovskite-based material during the preparation of the hydrogen electrode material. Combined with an in-situ dissolution strategy, this provides catalytically active nanoparticles while simultaneously filling vacancies left by B-site dissolution, thereby improving the poor catalytic activity and long-term high-temperature operational stability of existing catalytic materials used in CO2 RR processes in solid oxide electrolyzers. This invention prepares a hydrogen electrode material with the chemical formula Cu-La using a gas-phase migration strategy to load nanoparticles. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ (LSTF) This method improves the CO2RR activity of SOEC hydrogen electrode materials. Commercial cuprous oxide powder can sublimate at temperatures near its melting point and deposit onto the surface of the LSTF material under a purge of gas flow, greatly enhancing the CO2 electrolysis capability of the LSTF material. This results in good stability of the single cell during 1000 h of long-term operation without coking.

[0006] A hydrogen electrode material for a solid oxide electrolyzer includes a substrate electrode material and Cu loaded on the surface of the substrate electrode material. The Cu is loaded on the surface of the substrate through gas phase migration and exists in the form of Cu metal. The mass ratio of Cu is in the range of 0.5-5 wt%.

[0007] The mass percentage of Cu ranges from 1.5% to 2.5%.

[0008] The substrate electrode material is a perovskite material containing Fe at the B site.

[0009] The substrate electrode material is La 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ (LSTF).

[0010] The preparation method of the above-mentioned solid oxide electrolytic cell hydrogen electrode material includes the following steps:

[0011] The substrate material and Cu2O are placed in an inert atmosphere with a certain distance between them, and heat treatment is performed so that cuprous oxide diffuses to the surface of the substrate material in the form of gaseous atoms at high temperature.

[0012] The distance is 1-20cm.

[0013] The heat treatment temperature is 800-1100℃, and the time is 1-5h, preferably 2.5-3.5h.

[0014] The method for preparing the matrix material includes the following steps:

[0015] Step 1: According to La 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ Weigh out a certain mass of C according to the stoichiometric ratio. 16 H 36 O4Ti and a certain proportion of citric acid monohydrate are added to an appropriate amount of deionized water and stirred to dissolve, resulting in a clear solution.

[0016] Step 2: Add a certain proportion of La(NO3)3·6H2O and Sr(NO3) 2、 Pour Fe(NO3)3·9H2O into the solution described in step 1 and stir until homogeneous.

[0017] Step 3: Add a certain proportion of ethylenediaminetetraacetic acid and ammonia water, adjust the pH value, continue heating and stirring until the solution becomes a viscous gel state, dry and calcine to obtain powder.

[0018] The drying conditions are 100-150 ℃ for 5 h; the calcination conditions are 900-1100 ℃ for 5-10 h, with a heating rate of 1-10 ℃ / min.

[0019] Adjust the pH to 8-13.

[0020] A method for supplementing the B-site metal dissolution vacancies during the use of perovskite materials as hydrogen electrode materials in SOEC CO2 electrolysis includes the following steps:

[0021] The substrate material and Cu2O are placed in an inert atmosphere with a certain distance between them, and heat treatment is performed so that cuprous oxide diffuses to the surface of the substrate material in the form of gaseous atoms at high temperature.

[0022] The material is then subjected to a reduction process.

[0023] Application of hydrogen electrode materials for solid oxide electrolyzers in high-temperature electrolysis of CO2 to CO in solid oxide electrolyzers.

[0024] The solid oxide electrolyzer structure consists of a hydrogen electrode, a barrier layer, an electrolyte, and an oxygen electrode, used for high-temperature electrolysis of CO2 to produce CO; the hydrogen electrode uses Cu-La. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ The composite electrode is constructed with a barrier layer made of La. 0.4 Ce 0.6 O 2-δ (LDC), oxygen electrode uses PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 6-δ (PBSCF) material; electrolyte uses La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (LSGM) powder. Beneficial effects

[0025] The present invention relates to Cu-La nanoparticle-loaded materials. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ The solid oxide electrolytic cell hydrogen electrode material, prepared by a vapor-phase migration method, has the following advantages:

[0026] The elements within the material are evenly distributed, the synthesis method is simple and efficient, and the preparation process is straightforward.

[0027] When LSGM is used as the electrolyte, LDC as the barrier layer, and PBSCF as the oxygen electrode, the resulting full cell has a higher current density.

[0028] While in-situ dissolution improves electrolytic activity, it inevitably leaves B-site vacancies, affecting structural stability. Cu, migrating through the gas phase, can be captured by LSTF with oxygen vacancies without affecting the original phase structure. Cu nanoparticles not only provide active sites, significantly enhancing the CO2RR activity of the LSTF hydrogen electrode in SOEC, but also partially enter the perovskite phase during reduction, replenishing vacancies left by Fe dissolution at B sites and controlling the phase evolution of the perovskite substrate. Compared to conventional doping and dissolution strategies, this approach achieves higher reduction activity and lower impedance, among other improvements in electrochemical activity, while requiring lower metal loading.

[0029] Cu-LSTF, as an excellent hydrogen electrode material, can be used to prepare full cells for the electrolysis of CO2 to produce CO. The resulting full cells exhibit high electrolysis current density, reaching 2.28 A cm⁻¹ at 1.5 V at 800 °C. -2 It is about the same as that of a single cell with an LSTF as the hydrogen electrode. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the principle of electrode fabrication via vapor phase migration.

[0031] Figure 2 These are the XRD patterns of Cu-LSTF-3 and LSTF hydrogen electrode materials at room temperature;

[0032] Figure 3 These are XRD patterns of Cu-LSTF-x hydrogen electrode material at room temperature after deposition at different times;

[0033] Figure 4 These are the XRD patterns of Cu-LSTF-3 after in-situ high-temperature reduction under an atmosphere; where (a) is the overall diffraction pattern and (b) is a magnified local pattern.

[0034] Figure 5 The XRD patterns of Cu-LSTF-x after treatment in a 10% H2 / Ar atmosphere for 2 h are shown.

[0035] Figure 6 These are SEM images of the morphology of LSTF and Cu-LSTF-x powders before and after reduction;

[0036] Figure 7 These are EDX-mapping images of Cu-LSTF-3 morphology;

[0037] Figure 8 These are SEM and EDX-mapping images of the electrolyte sheet after the Cu-LSTF electrode on the surface has been removed.

[0038] Figure 9These are the HADDF-TEM and corresponding EDX-mapping images of the reduced Cu-LSTF-3;

[0039] Figure 10 It is an LSTF|LDC|LSGM|PBSCF single cell operating in fuel cell mode within a temperature range of 750-850 °C. I-V and I-P curve;

[0040] Figure 11 This refers to Cu-LSTF-3|LDC|LSGM|PBSCF single cells operating in fuel cell mode within a temperature range of 750-850 °C. I-V and I-P curve;

[0041] Figure 12 Electrochemical impedance spectroscopy of single cells of LSTF|LDC|LSGM|PBSCF and Cu-LSTF-3|LDC|LSGM|PBSCF measured at open-circuit voltage in the range of 750-850 °C.

[0042] Figure 13 These are the performance curves of LSTF|LDC|LSGM|PBSCF single cells for CO2 electrolysis within a temperature range of 700-850 °C;

[0043] Figure 14 The performance curves of Cu-LSTF-1|LDC|LSGM|PBSCF single cells for CO2 electrolysis within the temperature range of 700-850 °C are shown.

[0044] Figure 15 The performance curves of Cu-LSTF-3|LDC|LSGM|PBSCF single cells for CO2 electrolysis within the temperature range of 700-850 °C are shown.

[0045] Figure 16 The performance curves of Cu-LSTF-5|LDC|LSGM|PBSCF single cells for CO2 electrolysis within the temperature range of 700-850 °C are shown.

[0046] Figure 17 This is a comparison chart of the electrolytic performance of LSTF and Cu-LSTF-x at 800 °C;

[0047] Figure 18 It is a Cu-LSTF-3|LDC|LSGM|PBSCF single cell at -0.8 A cm⁻¹ -2 Long-term stability test of pure CO2 electrolysis at 800 °C under constant current density;

[0048] Figure 19This is a Raman test following the stability test of a single Cu-LSTF-3|LDC|LSGM|PBSCF cell. Detailed Implementation

[0049] This invention relates to a solid oxide electrolyzer (SOEC) hydrogen electrode material, its preparation method, and its applications, based on a vapor-phase migration method for loading nanoparticles. The Cu-La nanoparticles are prepared using a vapor-phase migration method involving powder sublimation at high temperatures. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ (LSTF), where δ represents the oxygen vacancy content, significantly improves the uniform dispersion of Cu atoms on the LSTF support compared to other traditional physical loading methods, thereby promoting the exposure of active sites. The migrating Cu atoms not only provide active sites but also greatly enhance the CO2 reduction activity of the LSTF hydrogen electrode in SOEC. Simultaneously, during the reduction process, some Cu elements enter the perovskite phase, filling the vacancies left by Fe dissolution at B sites and controlling the phase evolution of the perovskite substrate. Testing of SOECs using Cu-LSTF as the hydrogen electrode revealed that this easily prepared hydrogen electrode exhibits superior CO2 reduction capability compared to traditional solid oxide fuel electrodes. This novel hydrogen electrode material demonstrates excellent electrochemical performance and outstanding stability in long-term testing.

[0050] When using the oxygen-ion conductor electrolyte LSGM and PBSCF as the oxygen electrode, the corresponding single cell, at 800 °C in solid oxide electrolysis mode, can electrolyze CO2 to obtain -2.28 A cm⁻¹ at 1.5 V. -2 The maximum current density; in solid oxide fuel cell mode, the cell can achieve 1.27 W / cm². -2 The maximum output power was achieved. Good stability was maintained during a 1000-hour long-term electrolysis test without coking. This invention develops a method for preparing hydrogen electrode materials for solid oxide electrolyzers using a vapor-phase migration method to support nanoparticles, which greatly improves the electrochemical performance of solid oxide fuel cells and electrolyzers.

[0051] The electrolyte and cathode materials involved in this invention include, but are not limited to, the materials described in the following embodiments, and the optimization and preparation methods involved include, but are not limited to, the methods described in the following embodiments. Any modifications or equivalent substitutions to the technical solutions of this invention that do not depart from the spirit and scope of the invention should be covered within the protection scope of this invention. Example 1

[0052] This embodiment provides a Cu-La solid oxide electrolytic cell hydrogen electrode material with nanoparticles loaded by a vapor-phase migration method. 0.2 Sr0.8 Ti 0.3 Fe 0.7 O 3-δ The preparation method of [the substance] is as follows:

[0053] Weigh 4.0838 g of tetrabutyl titanate and 33.6224 g of citric acid monohydrate and dissolve them in an appropriate amount of deionized water. Then add 3.4640 g of lanthanum nitrate hexahydrate, 6.7722 g of strontium nitrate, and 11.312 g of ferric nitrate nonahydrate and stir to dissolve. Weigh 23.3792 g of ethylenediaminetetraacetic acid (EDTA) as a complexing agent according to the molar ratio of EDTA:citric acid monohydrate:metal ions = 1:2:1 and add an appropriate amount of deionized water.

[0054] (2) Add the obtained complexing agent to the dissolved metal ion solution, and then add an appropriate amount of ammonia water to adjust the pH range of the solution to 8-13. Then heat and stir until the water evaporates to obtain a gel-like substance.

[0055] (3) The gelatinous substance was placed in an oven at 150 °C to remove moisture and obtain the precursor.

[0056] (4) The obtained precursor was calcined in a high-temperature furnace at 1100 °C for 10 h to obtain LSTF electrode powder.

[0057] (5) Place the obtained LSTF powder at one end of a ceramic boat, add an appropriate amount of commercial cuprous oxide powder to the other end, place it in a tube furnace, and treat it under Ar atmosphere at 1000 ℃ for 3 h to obtain the final powder. Example 2

[0058] This embodiment provides a Cu-La 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ The preparation and testing method of a single cell for a hydrogen electrode includes the following specific steps:

[0059] (1) Weigh 1 g of the electrode powder La prepared in Example 1. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ The electrode slurry was obtained by ball milling in a high-energy ductile ink container with 10 mL of isopropanol, 2 mL of ethylene glycol, and 0.8 mL of glycerol for 30 min at 400 r / min.

[0060] (2) The prepared LSGM electrolyte sheet with an LDC barrier layer sprayed on one side was placed on a heating stage at 150 °C. The prepared LSTF electrode slurry was uniformly sprayed onto the surface of the LDC side using an inert gas and a spray gun. After the liquid completely evaporated, the sprayed electrolyte sheet was placed in a high-temperature furnace at 1000 °C for 2 h to obtain the desired single cell. After cooling, PBSCF was sprayed onto the other side of the LSGM electrolyte. The cell was placed on one side of a ceramic boat, and an appropriate amount of commercial cuprous oxide powder was added. The cell was then placed in a tube furnace and treated under an Ar atmosphere at 1000 °C for 3 h to obtain the final single cell. The peak power density of the cell measured in fuel cell mode at 800 °C was 1.27 W cm⁻¹. -2 Furthermore, the current density obtained in electrolytic cell mode was -2.28 A cm⁻¹. -2 (1.5 V).

[0061] Compare with Example 1

[0062] This comparative example is used to prepare the oxide La. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ (LSTF), the specific steps are as follows:

[0063] (1) Weigh 4.0838 g of tetrabutyl titanate and 33.6224 g of citric acid monohydrate and dissolve them in an appropriate amount of deionized water. Then add 3.4640 g of lanthanum nitrate hexahydrate, 6.7722 g of strontium nitrate and 11.312 g of ferric nitrate nonahydrate and stir to dissolve. Weigh 23.3792 g of ethylenediaminetetraacetic acid as a complexing agent according to the molar ratio of ethylenediaminetetraacetic acid:citric acid monohydrate:metal ions = 1:2:1 and add an appropriate amount of deionized water.

[0064] (2) Add the obtained complexing agent to the dissolved metal ion solution, and then add an appropriate amount of ammonia water to adjust the pH range of the solution to 8-13. Then heat and stir until the water evaporates to obtain a gel-like substance.

[0065] (3) The gelatinous substance was placed in an oven at 150 °C to remove moisture and obtain the precursor.

[0066] (4) The obtained precursor was placed in a high-temperature furnace at 1100 °C and calcined for 10 h to finally obtain the electrode powder.

[0067] Compare with Examples 2 and 3

[0068] The Cu-La prepared in Example 1 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O3-δ For powder, the processing time was changed from 3 hours in Example 1 to 1 or 5 hours.

[0069] Test Results

[0070] 1. X-ray diffraction (XRD) characterization

[0071] Figure 1 This is a schematic diagram illustrating the principle of vapor phase migration electrode fabrication. This simple method allows Cu to be loaded onto LSTF. Figure 2 These are the XRD patterns of Cu-LSTF-3 and LSTF hydrogen electrode materials at room temperature. The XRD patterns clearly show that the LSTF powder, after sintering in air at 1100 °C for 10 h, exhibits cubic perovskite La... 0.2 Sr 0.8 TiO3 structure. Cuprous oxide, in its gaseous atomic form, diffuses along an argon gas flow at high temperatures and can be captured by LSTF. Cu-LSTF-3 also interacts with La. 0.2 Sr 0.8 The standard peaks of TiO3 are completely consistent, but the characteristic peaks of metallic Cu are not present, possibly due to the small amount of migration.

[0072] Figure 3 These are the XRD patterns of Cu-LSTF-x at room temperature for different processing times, where x represents the processing time (0, 1, 3, and 5 hours). The XRD patterns clearly show that Cu-LSTF-x powders with different processing times also possess a cubic perovskite structure, similar to La. 0.2 Sr 0.8 The characteristic peaks of TiO3 remained consistent, and no additional peaks appeared. Furthermore, as the processing time increased, the main diffraction peak shifted to lower diffraction angles.

[0073] Figure 4 This is the in-situ XRD pattern of Cu-LSTF-3 material heated from room temperature to 800 °C in a 10% H2 / Ar atmosphere. Figure (b) shows that, under reducing atmosphere, characteristic peaks of elemental Cu appear at 43.3° and 50.4° as the temperature increases. This confirms that Cu in the treated LSTF exists in a metallic state.

[0074] Figure 5 The XRD pattern of Cu-LSTF-x after treatment in a 10% H2 / Ar atmosphere for 2 h shows that after reduction, the formation of the RP phase is clearly visible, and the characteristic peaks of Cu and Fe elements on the perovskite surface also appear.

[0075] 2. Scanning electron microscopy (SEM) characterization

[0076] Figure 6The images show the morphology of LSTF and Cu-LSTF-x powders before and after reduction using SEM. The SEM images clearly show that the morphologies of LSTF and Cu-LSTF powders are basically the same before reduction, both having smooth surfaces. However, the Fe nanoparticles precipitated from the reduced LSTF are larger, while the Cu-LSTF precipitates show a significantly increased particle density and a significantly smaller particle size. This indicates that Cu migration is beneficial for improving the precipitation of Fe elements in LSTF and increasing the number of active sites.

[0077] Figure 7 This is the EDX-mapping image corresponding to Cu-LSTF-3, showing the uniformity of the overall distribution of La, Sr, Ti, Fe, Cu and O elements. The proportions of each atom shown in the spectrum are close to the stoichiometric proportions, and the Cu element content is approximately 2 wt%.

[0078] Figure 8 The images are SEM and EDX-mapping images of the surface Cu-LSTF electrode after it was removed from the electrolyte sheet. The presence of Cu after removing the surface LSTF proves that Cu not only migrates to the electrode surface, but diffuses into the entire electrode interior.

[0079] 3. Characterization by High-Angle Annular Dark-Field Transmission Electron Microscopy (HADDF-TEM)

[0080] Figure 9 These are HADDF-TEM and corresponding EDX-mapping images of the reduced Cu-LSTF-3. The Cu-LSTF-3-R oxide was studied using high-resolution TEM; its lattice spacing is 2.80 Å, similar to that of La. 0.2 Sr 0.8 The (110) lattice planes of TiO3 correspond to the lattice spacing of the uniform nanoparticles on the surface, which are 2.03 Å and 2.08 Å, respectively, corresponding to the (110) lattice planes of Fe and Cu. EDX-mapping showed the uniformity of the overall distribution of La, Sr, Ti, Fe, Cu and O elements, and that Cu elements uniformly entered the LSTF bulk phase after reduction, filling the B-site vacancies caused by Fe dissolution.

[0081] 4. Fuel Cell Performance Testing

[0082] Assembly and testing of single cells: The single cell structure is LSTF|LDC|LSGM|PBSCF (active area 0.45 cm²). 2 The prepared single-cell electrodes were coated with silver paste, connected with silver wires, and sealed onto a 12 mm diameter ceramic tube using silver paste. The oxygen electrode side was directly exposed to air. Before testing, 70 ml of [unspecified substance] was introduced into the hydrogen electrode side. -1H2, heated to the test temperature. At open-circuit voltage, a current step of 30 mA was applied to the single cell, and the IV value of the cell was acquired using a Keithley 2420 digital source meter.

[0083] Figure 10 and Figure 11 These are LSTF|LDC|LSGM|PBSCF and Cu-LSTF-3|LDC|LSGM|PBSCF single cells operating in fuel cell mode within a temperature range of 850-750 °C. I-V and I-P The peak power densities of the Cu-LSTF-3 electrode at 850, 800, and 750 °C are 1.60, 1.27, and 0.89 W / cm², respectively. -2 The peak power of the LSTF electrode at 800 °C is only 0.8 Wcm. -2 .

[0084] Figure 12 These are the electrochemical impedance spectra of (a) a single cell LSTF|LDC|LSGM|PBSCF and (b) a single cell Cu-LSTF-3|LDC|LSGM|PBSCF, measured at open-circuit voltage in the range of 750–850 °C. The results show that the polarization impedance is 0.15 Ω cm⁻¹ at 850 °C. 2 Around 800 °C, the polarization impedance is 0.15 Ω cm. 2 The polarization impedance is approximately 0.21 Ω cm at 750 °C. 2 The polarization impedances of the LSTF at 850, 800, and 750 °C are approximately 0.22, 0.28, and 0.40 Ωcm, respectively. 2 .

[0085] 5. Electrolyte performance testing

[0086] The electrolyzer was assembled in the same manner as the fuel cell. The test conditions were changed to: before the test, 70 ml of hydrogen was introduced into the hydrogen electrode side. -1 H2, after heating to the test temperature, reduce for 20 min, then switch to 40 ml min. -1 CO2. At open-circuit voltage, a current step of -10 mA was applied to the single cell, and the IV value of the cell was acquired using a Keithley 2420 digital source meter.

[0087] Figure 13 and Figure 14 , 1516 represents LSTF|LDC|LSGM|PBSCF and single-cell Cu-LSTF-1|LDC|LSGM|PBSCF, Cu-LSTF-3|LDC|LSGM|PBSCF, and Cu-LSTF-5|LDC|LSGM|PBSCF, respectively, operating in electrolytic cell mode within a temperature range of 700-850 °C. I-V Curves; The current densities of Cu-LSTF-3 single cells electrolyzing at 1.5 V under pure CO2 conditions are -3.3, -2.28, -1.49, and -0.91 A cm⁻¹. -2 The LSTF single cell, under testing conditions of 800 °C and 1.5V, exhibits a current density of only -1.36 A cm⁻¹. -2 .

[0088] Figure 17 This is a comparison of the electrolytic performance of LSTF, Cu-LSTF-1, Cu-LSTF-3, and Cu-LSTF-5 within the temperature range of 700-850 °C; at 800 °C and 1.5 V, the corresponding current densities are -1.36, -1.60, -2.28, and -2.03 A cm⁻¹, respectively. -2 This indicates that the Cu-LSTF-3 electrode possesses excellent CO2RR activity.

[0089] 12. Single-cell durability test

[0090] Figure 18 At 800 °C, the Cu-LSTF-3 electrode is at -800 mA cm⁻¹ -2 Stability test of pure CO2 electrolysis at constant current density. During the 1000-h test, the voltage of the electrolytic cell remained stable at 1.5 V without significant degradation, indicating good long-term stability of the electrolytic cell.

[0091] Figure 19 After long-term stability testing of Cu-LSTF-3|LDC|LSGM|PBSCF single cells in a pure CO2 atmosphere at 800 °C, no obvious carbon deposition was observed in the Cu-LSTF-3 hydrogen electrode after Raman spectroscopy.

Claims

1. A solid oxide electrolytic cell hydrogen electrode material, characterized in that, The electrode comprises a substrate electrode material and Cu loaded on the surface of the substrate electrode material. The Cu is loaded onto the substrate surface via vapor-phase migration and exists in the form of Cu metal. The mass percentage of Cu ranges from 1.5% to 2.5%. The substrate electrode material is La. 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ ; The preparation method of the solid oxide electrolytic cell hydrogen electrode material includes the following steps: The substrate material and Cu2O are placed in an inert atmosphere with a certain distance between them, and heat treatment is performed so that cuprous oxide diffuses to the surface of the substrate material in the form of gaseous atoms at high temperature. The distance is 1-20cm; The heat treatment temperature is 800-1100℃, and the time is 1-5 hours; The method for preparing the matrix material includes the following steps: Step 1: According to La 0.2 Sr 0.8 Ti 0.3 Fe 0.7 O 3-δ Weigh out a certain mass of C according to the stoichiometric ratio. 16 H 36 O4Ti and a certain proportion of citric acid monohydrate are added to an appropriate amount of deionized water and stirred to dissolve, resulting in a clear solution. Step 2: Add a certain proportion of La(NO3)3·6H2O and Sr(NO3) 2、 Pour Fe(NO3)3·9H2O into the solution described in step 1 and stir until homogeneous; Step 3: Add a certain proportion of ethylenediaminetetraacetic acid and ammonia water, adjust the pH value, continue heating and stirring until the solution becomes a viscous gel state, dry and calcine to obtain powder.

2. The solid oxide electrolytic cell hydrogen electrode material according to claim 1, characterized in that, In step 3, the drying conditions are 100-150℃ for 5 hours; the calcination conditions are 900-1100℃ for 5-10 hours, with a heating rate of 1-10℃ / min.

3. The use of the hydrogen electrode material for a solid oxide electrolyzer according to claim 1 in the high-temperature electrolysis of CO2 to CO in a solid oxide electrolyzer.

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