Iron-titanium-based high-temperature solid oxide electrolytic cell anode material based on surface modification as well as preparation method and application of iron-titanium-based high-temperature solid oxide electrolytic cell anode material

Abstract

The invention discloses an iron-titanium-based high-temperature solid oxide electrolytic cell anode material based on surface modification and a preparation method and application thereof. The method comprises the following steps: impregnating an STF anode with ammonium metavanadate, and heating at 400-600 DEG C to obtain a V2O5 modified V2O5-STF anode; the anode material has high ethane oxidative dehydrogenation activity and high ethylene selectivity, and an effective solution is provided for efficient conversion of ethane into ethylene. Under the temperature of 750 DEG C, the ethane conversion rate of a solid oxide electrolytic tank with a V2O5-STF anode is improved by 12.7% compared with that of the original unmodified STF, the ethylene selectivity is slightly reduced, but the selectivity is still kept to be about 90%, the ethylene yield of 65% at most is finally obtained, and the ethylene yield is obviously improved by about 10% compared with that of the original STF. The method is one of the highest yields of electrochemical ethane oxidative dehydrogenation by taking CO2 as an oxidizing agent, and has remarkable advantages compared with thermal chemical ethane oxidative dehydrogenation under similar conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalytic materials, and specifically relates to a method for preparing an anode material of an iron-titanium-based high-temperature solid oxide electrolytic cell based on surface modification and its application in alkane oxidative dehydrogenation to olefins. Background Art

[0002] Ethane is the second most abundant component in natural gas and shale gas, and is also a valuable raw material for ethylene production. Ethylene is a basic raw material for petrochemicals and plays an important role in the national economy. Traditional naphtha cracking and fluid catalytic cracking to produce olefins are subject to thermodynamic limitations and have many side reactions, resulting in high process energy consumption and low selectivity. With the continuous growth of ethylene demand and the discovery of a large amount of shale gas, ethane dehydrogenation to ethylene technology has attracted the attention of researchers due to its high selectivity and economic competitiveness.

[0003] The electrochemical conversion of ethane oxidative dehydrogenation based on solid oxide electrolysis cell (SOEC) has received extensive attention [Applied Catalysis B: Environmental, 2018, 227: 90-101.]. SOEC is an energy conversion device with a fully solid structure, no need for precious metal catalysts, and operating under high temperature conditions. It can realize the conversion of thermal energy and electrical energy into chemical energy, and the electrolysis efficiency is as high as 98%. Ethane is passed into the anode and O is passed into the other side. 2 , CO 2 or H 2 O, the dense electrolyte separates the gases on both sides, avoiding the occurrence of direct combustion reactions. By applying different bias voltages, the current can be adjusted to control the amount of oxygen species participating in the oxidative dehydrogenation reaction on the anode side, thereby inhibiting the formation of coke and deep oxidation. At the same time, the cathode side can be electrolyzed to produce synthesis gas, achieving high-value products on both sides. In recent years, the greenhouse gas carbon dioxide (CO 2 ) emissions are increasing and urgently need to be managed. 2 Conversion to CO is an important topic at present, and SOEC provides a good solution for it. In SOEC, high-temperature electrochemical oxidation of ethane to ethylene is coupled to CO 2 Reduction to CO is a strategy with great research potential, showing broad prospects in energy conversion and efficient utilization of resources.

[0004] The electrode material of SOEC is crucial for the catalytic activity and reaction process of high-temperature electrochemical ethane ODH. Selecting a suitable electrode material as a catalyst can reduce the reaction barrier, accelerate the reaction kinetics, select the reaction path, improve the conversion rate of ethane, inhibit over-oxidation and improve the selectivity of ethylene. Perovskite materials are ideal materials for SOCE electrodes because of their high thermal / chemical stability and multiple selectivity of composition. Song et al. modified a layer of Al on the surface of the LSCF-SDC anode. 2 O 3 After optimizing the flow rate, the ethylene selectivity was as high as 92.5%, while the ethane conversion rate was as high as 29.1% at 600°C [Angewandte Chemie International Edition, 2019, 58(45): 16043-16046.]. Sun et al. studied STCF as an electrode material and proved that SOEC can effectively catalyze the oxidative dehydrogenation of ethane to produce ethylene at the anode and convert CO to ethylene at the cathode. 2 Reduction to CO. The optimal yield of ethylene reached 66.3% at 800°C, which is one of the highest values ​​reported in the literature [ACS Catalysis, 2024, 14(8): 5827-5837.]. However, as a key component of SOEC, the catalytic conversion activity and stability of perovskite electrode materials for ethane need to be improved, and the mechanism of the influence of changes in the surface properties of electrode materials on the high-temperature electrochemical ethane oxidative dehydrogenation reaction process is still unclear. These problems still need to be further resolved. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing an iron-titanium-based high-temperature solid oxide electrolytic cell anode material based on surface modification and its application in alkane oxidative dehydrogenation to olefins.

[0006] The primary purpose of the present invention is to provide a method for preparing an anode material for an iron-titanium-based high-temperature solid oxide electrolytic cell based on surface modification.

[0007] Another object of the present invention is to provide the above-mentioned preparation method to prepare the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material.

[0008] Another object of the present invention is to provide the above-mentioned surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in ethane oxidative dehydrogenation coupled electrolysis of CO 2 Application in reaction.

[0009] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0010] The invention provides a method for preparing an iron-titanium-based high-temperature solid oxide electrolytic cell anode material based on surface modification. The preparation method comprises: dripping an ammonium metavanadate solution in small amounts and multiple times into a porous STF anode, heating and drying, and then sintering at high temperature to obtain the iron-titanium-based high-temperature solid oxide electrolytic cell anode material based on surface modification.

[0011] The present invention provides a method for preparing an anode material for an iron-titanium-based high-temperature solid oxide electrolytic cell based on surface modification, which specifically comprises the following steps:

[0012] (1) dissolving an appropriate amount of ammonium metavanadate in deionized water to obtain an ammonium metavanadate solution of a certain concentration;

[0013] (2) shaking the solution of step (1) and dropping an appropriate amount of the solution into the porous anode of the anode of the high-temperature solid oxide electrolytic cell, and drying;

[0014] (3) repeating step (2), dripping the solution in small amounts and multiple times into the porous anode of the high temperature solid oxide electrolytic cell, and drying;

[0015] (4) placing the porous electrode described in step (3) in a tubular furnace and calcining it into V 2 O 5 phase, get V 2 O 5 The loading amount is 0.05-1.0 mg cm -2 .

[0016] Furthermore, the molar volume percentage concentration of the ammonium metavanadate solution in step (1) is 0.01-0.2 mol / L.

[0017] Preferably, the molar volume percentage concentration of the ammonium metavanadate solution in step (1) is 0.03-0.10 mol / L, and the solvent is deionized water.

[0018] Furthermore, in step (2), the drying method is one of natural drying, vacuum drying, etc.; the drying temperature is 50-70° C., and the drying time is 30-120 min, preferably 30-60 min.

[0019] Preferably, in step (2), the drying method is vacuum drying; the drying temperature is 60° C., and the drying time is 30 min.

[0020] Furthermore, in step (3), after the temperature drops to room temperature after drying, step (2) is repeated; the drying time is 30-120 min, preferably 30-60 min.

[0021] Preferably, in step (3), after the temperature drops to room temperature after drying, step (2) is repeated; the drying time is 30 minutes.

[0022] Furthermore, the calcination temperature in step (4) is 400-600°C.

[0023] Preferably, the calcination temperature in step (4) is 400-500°C.

[0024] Furthermore, the calcination heating rate in step (4) is 2-5°C / min.

[0025] Preferably, the calcination heating rate in step (4) is 2-3°C / min.

[0026] Furthermore, the calcination time in step (4) is 60-180 min.

[0027] Preferably, the calcination time in step (4) is 120-150 min.

[0028] Furthermore, in step (4), V 2 O 5 The loading amount is 0.05-1.0 mg cm -2 .

[0029] Preferably, step (4) V 2 O 5 The loading capacity is 0.10-0.35 mg cm -2 .

[0030] The present invention also provides a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material for ethane oxidative dehydrogenation coupled electrolysis of CO 2 Application in reaction.

[0031] The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material of the present invention has the advantages of simple preparation process, non-toxic and harmless preparation process, low preparation cost, strong universality of the preparation method, flexible and controllable preparation process, large-scale batch production, easy adjustment of the resulting battery components, etc. The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material prepared under the preferred conditions of the present invention has excellent ethane oxidative dehydrogenation performance and high ethylene selectivity.

[0032] The V with high efficiency and high ethylene selectivity obtained by the present invention is 2 O 5 Modified V 2 O 5 -STF composite electrode as anode, Sr 2 Ti 0.8 Co 0.2 FeO 6-δ (STCF) as cathode, La 0.8 Sr 0.2 Ga 0.83 Mg0.17 O 3-δ (LSGM) was used as the electrolyte to assemble a high-temperature solid oxide electrolytic cell. At 750 °C, the impregnated anode V 2 O 5 -STF has a significant improvement in ethane oxidative dehydrogenation performance compared to the original unmodified STF. 2 O 5 -The ethane conversion rate of the solid oxide electrolyzer with STF anode increased by 12.7% compared with the original unmodified STF, and the ethylene selectivity decreased slightly but still maintained a selectivity of nearly 90%, ultimately obtaining a maximum ethylene yield of 65%, which is a significant increase of about 10% compared with the original STF.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material provided by the present invention has low raw material cost, low sintering temperature, low energy consumption in the production process, and low production cost.

[0035] 2. The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material provided by the present invention adopts a solution impregnation strategy for its preparation method, which can be used to prepare composite anodes with different proportions of transition metal elements and still has great development potential for different reactions.

[0036] 3. The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material provided by the present invention has a simple and easy preparation process, a short preparation cycle, can be mass-produced, and has commercial prospects.

[0037] 4. The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material provided by the present invention does not produce any toxic gas during its preparation process and is green, environmentally friendly and pollution-free.

[0038] 5. The high efficiency and high ethylene selectivity V obtained by the present invention 2 O 5 Modified V 2 O 5 -STF composite electrode as anode, Sr 2 Ti 0.8 Co 0.2 FeO 6-δ (STCF) as cathode, La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 3-δ (LSGM) was used as the electrolyte to assemble a high-temperature solid oxide electrolytic cell. At 750 °C, the impregnated anode V 2 O 5-STF has a significant improvement in ethane oxidative dehydrogenation performance compared to the original unmodified STF. 2 O 5 -The ethane conversion rate of the solid oxide electrolyzer with STF anode increased by 12.7% compared with the original unmodified STF, and the ethylene selectivity decreased slightly but still maintained a selectivity of nearly 90%, ultimately obtaining a maximum ethylene yield of 65%, which is a significant increase of about 10% compared with the original STF. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 are shown.

[0040] Figure 2 These are scanning electron microscope (SEM) images and X-ray energy spectrum (EDS) images of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 before impregnation.

[0041] Figure 3 These are the X-ray diffraction (XRD) patterns of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 before and after impregnation and after calcination of ammonium metavanadate at 400°C.

[0042] Figure 4 This is the volt-ampere characteristic curve (IV) of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 in a high-temperature solid oxide electrolytic cell.

[0043] Figure 5 This is the AC impedance spectrum of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 in a high-temperature solid oxide electrolytic cell.

[0044] Figure 6 This is a complete single cell based on the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 2 and applied to a high-temperature solid oxide electrolytic cell, as well as a diagram of the electrode and electrolyte interface.

[0045] Figure 7 The product composition and ethane conversion rate of ethane oxidative dehydrogenation of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 2 at different voltages in the high-temperature solid oxide electrolytic cell.

[0046] Figure 8 The ethane conversion rates of the surface-modified iron-titanium-based high-temperature solid oxide electrolysis cell anode material in Example 3 and the untreated high-temperature solid oxide electrolysis cell STF anode in Comparative Example 1 at different ethane feed flow rates in the high-temperature solid oxide electrolysis cell.

[0047] Fig. 9 The ethylene selectivity of the surface-modified iron-titanium-based high-temperature solid oxide electrolyzer anode material in Example 3 and the untreated high-temperature solid oxide electrolyzer STF anode in Comparative Example 1 at different ethane feed flow rates in the high-temperature solid oxide electrolyzer.

[0048] Fig.10 The ethylene yields of the surface-modified iron-titanium-based high-temperature solid oxide electrolyzer anode material in Example 3 and the untreated high-temperature solid oxide electrolyzer STF anode in Comparative Example 1 at different ethane feed flow rates in the high-temperature solid oxide electrolyzer.

[0049] Fig.11 The CO generation rate and Faraday efficiency of the surface-modified iron-titanium-based high-temperature solid oxide electrolysis cell anode material in Example 3 and the untreated high-temperature solid oxide electrolysis cell STF anode in Comparative Example 1 on the cathode side of the high-temperature solid oxide electrolysis cell.

[0050] Fig.12 This is the volt-ampere characteristic curve (IV) of the untreated high-temperature solid oxide electrolysis cell STF anode in the high-temperature solid oxide electrolysis cell in Comparative Example 1.

[0051] Fig.13 This is the AC impedance spectrum of the untreated STF anode in the high-temperature solid oxide electrolysis cell in Comparative Example 1. DETAILED DESCRIPTION

[0052] The specific implementation of the present invention is further described below in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0053] Example 1

[0054] (1) Dissolve an appropriate amount of ammonium metavanadate in deionized water to obtain an ammonium metavanadate solution with a molar concentration of 0.05 mol / L.

[0055] (2) STF (iron-titanium-based high-temperature solid oxide electrolytic cell anode material SrFe 0.9 Ti 0.1 O 3 ), graphite, α-pinene alcohol and polyvinyl butyral were mixed and ground for 3 hours to obtain STF electrode slurry. The STF slurry was brushed onto one side of the LSGM electrolyte and sintered at 1100°C for 2 hours to prepare a porous anode for a solid oxide fuel cell.

[0056] (3) Shake the solution in step (1) and use a pipette to take 5 μL of the solution and drop it into the porous anode of the solid oxide fuel cell prepared in step (2). Heat and dry under vacuum at 60° C. for 30 min.

[0057] (4) Repeat step (2), drip the solution into the porous anode of the high-temperature solid oxide electrolytic cell prepared in step (2) in small amounts and multiple times (specifically, dripping three times, each dripping amount is 5 μL), and vacuum heat drying at a temperature of 60° C. for 30 min.

[0058] (5) placing the porous electrode described in step (4) in a tubular furnace, heating to 400° C. at a rate of 2° C. / min and calcining for 120 min to obtain V 2 O 5 The loading amount was 0.11 mg cm -2 .

[0059] The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material obtained in Example 1 are as follows: Figure 1 As shown by Figure 1 It can be seen that V 2 O 5 -STF anode elements are evenly distributed and fit the material morphology, with a layer of V on the surface 2 O 5 cover.

[0060] The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material before impregnation in Example 1 are as follows: Figure 2 As shown by Figure 2 It can be seen that the STF anode has a porous structure, which is impregnated with V 2 O 5 Sufficient space is provided, and the elements are evenly distributed and fit the material morphology map.

[0061] The X-ray diffraction (XRD) patterns of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material before and after impregnation and after calcination of ammonium metavanadate at 400°C in Example 1 are as follows: Figure 3 As shown by Figure 3 It can be seen that the STF anode is immersed in V 2 O 5 No new diffraction peaks appeared in the XRD spectrum, indicating that the STF phase structure did not change after impregnation. The XRD pattern of the material obtained by calcining the ammonium metavanadate solution at 400 °C was similar to that of V 2 O 5 The PDF card is consistent with that of 2 O 5The prepared modified electrode is V 2 O 5 -STF anode.

[0062] The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material of Example 1 was applied in a high-temperature solid oxide electrolytic cell. Test conditions: Silver paste and ceramic sealant were used to seal the high-temperature solid oxide fuel cell to a glass tube. Silver grids were used as current collectors on both electrodes of the cell. The assembled porous cell was assembled in a dual-chamber test furnace, heated to 750°C, and heated at 20-50 mL min -1 Pure CO is supplied to the cathode at a flow rate of 2 10-50 mL min is supplied to the anode side. -1 10-50%C 2 H 6 / Ar. Figure 4 This is the volt-ampere characteristic curve (IV) of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material in Example 1 in a high-temperature solid oxide electrolytic cell. Figure 5 This is the constant voltage electrochemical impedance spectroscopy (EIS) of the surface modified iron-titanium-based high temperature solid oxide electrolytic cell anode material in the high temperature solid oxide electrolytic cell at 1.0 V in the frequency range of 100 kHz to 100 mHz in Example 1. All electrochemical tests were performed using the Zennium series electrochemical workstation from the German ZAHNER company.

[0063] Example 2

[0064] (1) Dissolve an appropriate amount of ammonium metavanadate in deionized water to obtain an ammonium metavanadate solution with a molar concentration of 0.1 mol / L.

[0065] (2) Shake the solution in step (1) evenly, take 5 μL of the solution with a pipette and drop it into the porous anode of the solid oxide fuel cell, and heat and dry it under vacuum at a temperature of 60° C. for 30 min.

[0066] (3) Repeat step (2) and drip the solution into the porous anode of the high-temperature solid oxide electrolytic cell in small amounts and multiple times (specifically, the number of dripping times is 5 times, and the amount of each dripping is 6 μL). Vacuum heating and drying at a temperature of 60° C. is performed for 30 min.

[0067] (4) placing the porous electrode described in step (3) in a tubular furnace, heating to 450°C at a rate of 3°C / min and calcining for 120 min to obtain V 2 O 5 The loading amount was 0.20 mg cm -2 .

[0068] The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material obtained in Example 2 are as follows: Figure 1 As shown by Figure 1 It can be seen that V 2 O 5 -STF anode elements are evenly distributed and fit the material morphology, with a layer of V on the surface 2 O 5 cover.

[0069] The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material before impregnation in Example 2 are as follows: Figure 2 As shown by Figure 2 It can be seen that the STF anode has a porous structure, which is impregnated with V 2 O 5 Sufficient space is provided, and the elements are evenly distributed and fit the material morphology map.

[0070] The X-ray diffraction (XRD) patterns of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material before and after impregnation and after calcination of ammonium metavanadate at 400°C in Example 2 are as follows: Figure 3 As shown by Figure 3 It can be seen that the STF anode is immersed in V 2 O 5 No new diffraction peaks appeared in the XRD spectrum, indicating that the STF phase structure did not change after impregnation. The XRD pattern of the material obtained by calcining the ammonium metavanadate solution at 400 °C was similar to that of V 2 O 5 The PDF card is consistent with that of 2 O 5 The prepared modified electrode is V 2 O 5 -STF anode.

[0071] The complete single cell and the electrode and electrolyte interface diagram of the surface modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material used in the high-temperature solid oxide electrolytic cell in Example 2 are shown in FIG. Figure 6 As shown, it can be seen that the electrode and the electrolyte form a good interface, which is conducive to the transmission of oxygen ions.

[0072] The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material of Example 2 was applied in a high-temperature solid oxide electrolytic cell. Test conditions: Silver paste and ceramic sealant were used to seal the high-temperature solid oxide fuel cell to a glass tube. Silver grids were used as current collectors on both electrodes of the cell. The assembled porous cell was assembled in a dual-chamber test furnace, heated to 750°C, and heated at 20-50 mL min-1 Pure CO is supplied to the cathode at a flow rate of 2 10-50 mL min is supplied to the anode side. -1 10-50%C 2 H 6 / Ar. The electrochemical test of the electrolytic cell was carried out using EIS (100kHz to 100mHz), LSV and other modes on an electrochemical workstation (IM6, Zahner, Germany), and the gas products at different applied voltages were analyzed online using gas chromatography (GC9790II, Fuli, Zhejiang, China). Figure 7 The high-efficiency, high-ethylene-selectivity high-temperature solid oxide electrolysis cell V in Example 2 2 O 5 -STF anode ethane oxidative dehydrogenation product composition and ethane conversion rate at different voltages (0.0-1.2V) in a high-temperature solid oxide electrolysis cell. As the applied voltage increases, the ethane conversion rate increases.

[0073] Example 3

[0074] (1) Dissolve an appropriate amount of ammonium metavanadate in deionized water to obtain an ammonium metavanadate solution with a molar concentration of 0.05 mol / L.

[0075] (2) Shake the solution in step (1) evenly, take 5 μL of the solution with a pipette and drop it into the porous anode of the solid oxide fuel cell, and heat and dry it under vacuum at a temperature of 60° C. for 30 min.

[0076] (3) Repeat step (2) and drip the solution into the porous anode of the high-temperature solid oxide electrolytic cell in small amounts and multiple times (specifically, the number of dripping times is 5 times, and the amount of each dripping is 4 μL). Vacuum heating and drying at a temperature of 60° C. and drying for 30 min.

[0077] (4) placing the porous electrode described in step (3) in a tubular furnace, heating to 450°C at a rate of 3°C / min and calcining for 150min to obtain V 2 O 5 The loading amount was 0.15 mg cm -2 .

[0078] The surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material of Example 2 was applied to a high-temperature solid oxide electrolytic cell. The assembled porous battery was installed in a double-chamber test furnace, heated to 750°C, and heated at 20-50 mL·min -1 Pure CO is supplied to the cathode at a flow rate of 2 and supply different flow rates (10-50 mL min -1 ) 10-50%C 2 H 6 / Ar. The applied voltage was 1.0V. During this period, the product content was analyzed using a Fuli GC97902 gas chromatograph. The ethane conversion rate was calculated based on the test results ( Figure 8 ), ethylene selectivity ( Fig. 9 ) and ethylene yield ( Fig.11 ), and the CO generation rate of the cathode product was analyzed by calculating the Faraday efficiency as Fig.12 shown.

[0079] Comparative Example 1

[0080] (1) Preparation of porous STF anode for high-temperature solid oxide fuel cells.

[0081] (2) Assembling the porous STF anode described in step (1) into a single cell.

[0082] The scanning electron microscope (SEM) image and X-ray energy spectrum (EDS) image of the untreated high temperature solid oxide electrolytic cell anode obtained in Comparative Example 1 are as follows: Figure 2 As shown, the untreated STF anode of the high temperature solid oxide electrolysis cell has a porous structure and a smooth surface.

[0083] The X-ray diffraction (XRD) pattern of the untreated high temperature solid oxide electrolytic cell STF anode obtained in Comparative Example 1 is as follows: Figure 3 As shown, it corresponds to PDF-40-0905 and is in good condition.

[0084] The untreated high temperature solid oxide electrolysis cell STF anode obtained in Comparative Example 1 was used in a high temperature solid oxide electrolysis cell. Test conditions: Silver paste and ceramic sealant were used to seal the high temperature solid oxide fuel cell to a glass tube. Silver grids were used as current collectors on both electrodes of the cell. The assembled porous cell was assembled in a dual chamber test furnace, heated to 750°C, and heated at 20-50 mL min -1 Pure CO is supplied to the cathode at a flow rate of 2 10-50 mL min is supplied to the anode side. -1 10-50%C 2 H 6 / Ar. All electrochemical tests were performed using the Zennium series electrochemical workstation from the German company ZAHNER to obtain the current-voltage (IV) curves, such as Fig.12 As shown in the figure, and the impedance spectrum curve at 1.0V, as shown in the figure Fig.13 shown.

[0085] The untreated high-temperature solid oxide electrolytic cell STF anode obtained in Comparative Example 1 was applied to a solid oxide electrolytic cell, and the product was analyzed for content at an applied voltage of 1.0 V. The testing instrument was a Fuli GC97902 gas chromatograph. The ethane conversion rate ( Figure 8 ), ethylene selectivity ( Fig. 9 ) and ethylene yield ( Fig.11 ), and the CO generation rate of the cathode product was analyzed by calculating the Faraday efficiency as Fig.12 shown.

[0086] Effect analysis

[0087] Combination Figure 1 , Figure 2 and Figure 3 The results show that the embodiment of the present invention can uniformly deposit the target active element V by a simple impregnation method. 2 O 5 The surface of the STF anode was modified to prepare a surface modified iron-titanium based high temperature solid oxide electrolytic cell anode material.

[0088] Combination Figure 4 , Figure 5 , Fig.12 and Fig.13 The results show that the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material prepared in the embodiment of the present invention has good electrochemical properties when used in a high-temperature solid oxide electrolytic cell, can generate a higher current density under the same applied voltage, and also has a smaller ohmic impedance.

[0089] Figure 6 The results show that the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material prepared in the embodiment of the present invention has good effect in the preparation of high-temperature solid oxide electrolytic cells. Figure 7 The results show that the conversion rate of ethane on the anode side increases with the increase of voltage, which reflects the excellent effect of high-temperature electrochemistry on ethane oxidative dehydrogenation. Fig.11 The CO generation rate and Faraday efficiency on the cathode side are shown. The results show that the surface-modified Fe-Ti-based high-temperature solid oxide electrolysis cell anode material prepared by simple impregnation can be applied to high-temperature solid oxide electrolysis cells. 2 The Faraday efficiency of electrolysis reaches more than 85%, proving that its power conversion efficiency is high.

[0090] Combination Figure 8 , Fig. 9 and Fig.10 The results show that the embodiment of the present invention prepares a high-efficiency, high-ethylene selectivity high-temperature solid oxide electrolyzer V 2 O 5-STF anode has high ethane oxidative dehydrogenation activity and high ethylene selectivity, providing an effective solution for achieving efficient conversion of ethane into ethylene. At 750℃, the impregnated anode V 2 O 5 -STF has significantly improved the ethane oxidative dehydrogenation performance compared to the original unmodified STF. The ethane conversion rate of the solid oxide electrolyzer with V2O5-STF anode increased by 12.7% compared to the original unmodified STF, and the ethylene selectivity decreased slightly but still maintained nearly 90% selectivity, and finally obtained a maximum ethylene yield of 65%, which is a significant improvement of about 10% compared to the original STF.

Claims

1. A method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material, characterized in that: The steps include: (1) dissolving ammonium metavanadate in a solvent to obtain an ammonium metavanadate solution; (2) shaking the ammonium metavanadate solution obtained in step (1) and then dripping it into the porous anode of the high-temperature solid oxide electrolytic cell and drying it; (3) repeating step (2), dripping the ammonium metavanadate solution in small amounts and multiple times into the porous anode of the high temperature solid oxide electrolytic cell, and drying; (4) placing the porous electrode obtained in step (3) in a tubular furnace and calcining it into a V2O5 phase, wherein the V2O5 loading amount in the V2O5 phase is 0.05-1.0 mg cm -2 .

2. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (1), the concentration of the ammonium metavanadate solution is 0.01-0.2 mol L -1 .

3. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (1), the solvent is deionized water.

4. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (2), the drying method is heating drying at 50-70° C.; the drying time is 30-120 min.

5. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (3), the small amount and multiple times refers to the number of dripping is 2-10 times, and the amount of each dripping is 3-10 μL.

6. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (3), after the temperature drops to room temperature after drying, step (2) is repeated; the drying time is 30-120 minutes.

7. The method for preparing a surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 1, characterized in that: In step (4), the calcination temperature is 400-600° C. and the calcination time is 60-180 min.

8. A surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The anode material has high ethane oxidative dehydrogenation activity and high ethylene selectivity; at 750°C, the ethane conversion rate of the solid oxide electrolysis cell with V2O5-STF anode is increased by 12.7% compared with the original unmodified STF, the ethylene selectivity is slightly reduced but still maintains nearly 90% selectivity, and finally a maximum ethylene yield of 65% is obtained, which is a significant increase of about 10% compared with the original STF.

9. Application of the surface-modified iron-titanium-based high-temperature solid oxide electrolytic cell anode material according to claim 8 in the oxidative dehydrogenation of alkanes to olefins.

10. The use according to claim 9, characterized in that: The surface modified iron-titanium based high temperature solid oxide electrolytic cell anode material is used as the anode, Sr2Ti 0.8 Co 0.2 FeO 6-δ STCF as cathode, La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 3-δ LSGM was used as the electrolyte to assemble a high-temperature solid oxide electrolytic cell. The assembled porous battery was installed in a double-chamber test furnace and heated to 750 °C at a rate of 20-50 mL min -1 Pure CO2 is supplied to the cathode at a flow rate of 10-50 mL min-1 and to the anode at a flow rate of 10-50 mL min-1. -1 10-100% C2H6 / Ar.

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