A high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode and its preparation method and application

Abstract

The present invention discloses a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity, as well as its preparation method and application. Cerium nitrate is impregnated into Ni / BZCYYb and heated to obtain CeO2-modified Ni / BZCYYb porous fuel electrode. CeO2-modified Ni / BZCYYb porous fuel electrode has high output power density and high CO2 catalytic activity, which improves the current situation of poor performance of Ni-based catalysts at medium and low temperatures and low CH4 production during electrolysis. In battery mode, the output power density at 600℃ and 550℃ is 663mWcm respectively. ‑2 and 438mWcm ‑2 CO2 was introduced into the CeO2-modified Ni / BZCYYb porous fuel electrode at 550℃ and 892mA / cm 2 and 1250mA / cm 2 The voltages are only 1.42V and 1.51V respectively at the current density of .

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and specifically relates to a high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode and a preparation method and application thereof. Background Art

[0002] The extensive use of fossil fuels and the sharp decline in forest area have led to a continuous increase in atmospheric carbon dioxide levels, resulting in an increasingly serious threat of global warming. Therefore, there is an urgent need to develop advanced energy storage and conversion technologies. Solid oxide batteries (SOBs) are highly efficient energy conversion devices that can convert chemical energy into electrical energy. They can efficiently generate electricity from clean fuels such as hydrogen. They can also electrolyze CO2 and water to produce hydrogen and carbon monoxide synthesis gas, which, when coupled with the Fischer-Tropsch synthesis reaction, can produce chemical feedstocks such as liquid hydrocarbons or small-molecule alcohols. This pathway not only effectively utilizes waste gases and waste heat generated in chemical processes but also allows for carbon sequestration by converting CO2 into liquid carbon-containing products. Furthermore, renewable energy sources (such as solar, wind, tidal, and geothermal energy) have developed rapidly in recent years, but their uneven spatial and temporal distribution has limited their practical application. SOBs, which utilize renewable energy to convert CO2 or hydroelectricity into useful chemicals or fuels, can effectively reduce atmospheric CO2 concentrations while providing a stable energy storage method for renewable energy.

[0003] The conventional oxygen ion conductor solid oxide electrolysis cell (O-SOEC) produces CO / H2 synthesis gas by introducing H2O and CO2 into the porous fuel electrode for co-electrolysis. The oxygen ions released are transported to the oxygen electrode through the electrolyte and lose electrons to produce oxygen. The proton conductor solid oxide electrolysis cell (PCEC) produces CO2 by introducing CO2 into the porous fuel electrode and H2O into the oxygen electrode for co-electrolysis. + The CO2 is transported through the electrolyte to the porous fuel electrode, where it reacts with the CO2 to produce gases such as H2, CO, and CH4. Compared to O-SOEC, PCEC mechanically separates H2O and CO2, simplifying the system and reducing operating costs. Furthermore, PCEC requires a lower operating temperature (400-600°C) than O-SOEC (600-800°C), significantly reducing heating costs.

[0004] Pt was the most commonly used fuel electrode material in early research (Solid State Ionics, 1986, 18(part-P2): 1003-1007.). Ni was also suggested as a fuel electrode material to reduce the cost of practical applications (PureAnd Applied Chemistry, 2013, 85(2): 427-435. doi:10.1351 / PAC-CON-12-07-11). Existing literature reports that although Pt and Ni perform well in proton conducting electrolytes based on BaCeO3 and SrCeO3, their performance deteriorates with increasing Zr content in the electrolyte. The literature discloses that at low current density (0-400 mAcm -1 ) The hydrogen production rate is 0-75 μmol min -1 cm -2 , but the actual hydrogen production rate at 800 °C is only 50% of the theoretical hydrogen production rate (International Journal Of Hydrogen Energy, 2009, 34(1): 56-63.). This means that Pt or Ni alone are not suitable choices for chemically stable electrolytes for proton-conducting SOECs. One reason for the poor performance of these electrodes is the limited length of the three-phase interface. Currently, the most common strategy to expand TPB to a larger electrode area is to apply a composite fuel electrode composed of metal and electrolyte oxides (Journal OfThe Electrochemical Society, 2012, 159(11): F763-F767.doi:10.1149 / 2.018212jes), which may be an ideal proton-conducting SOEC fuel electrode: first, for PCEC, porous fuel electrodes are usually used as supports, and Ni is relatively low in cost, making it suitable for practical applications. Second, Ni shows high electrical conductivity, providing a pathway for electron conduction. Third, Ni exhibits good chemical compatibility with most existing proton-conducting oxides, even at temperatures as high as 1400°C, which facilitates the fabrication of PCECs using Ni-based porous fuel electrodes. However, key issues in CO2 electrolysis, such as the low chemical stability of electrolyte oxides, poor cell performance, and low CH4 selectivity, remain to be addressed. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention aims to provide a highly efficient and highly CH4 selective proton conductor solid oxide reversible battery porous fuel electrode and its preparation method and application.

[0006] The primary purpose of the present invention is to provide a method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity by simple impregnation.

[0007] Another object of the present invention is to provide the above-mentioned preparation method to prepare a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity.

[0008] Another object of the present invention is to provide the application of the above-mentioned high-efficiency, high CH4 selectivity proton conductor solid oxide reversible battery porous fuel electrode in hydrogen oxidation power generation or CO2 electrolysis reaction.

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

[0010] The present invention provides a method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity by simple impregnation. The preparation method comprises: dripping a cerium nitrate solution into a cleaned and dried Ni / BZCYYb porous fuel electrode, wherein BZCYYb is BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ (δ is the non-stoichiometric number of oxygen), and after drying, high-temperature sintering is performed to obtain the highly efficient, highly CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

[0011] The present invention provides a method for preparing a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity by an impregnation method, which specifically comprises the following steps:

[0012] (1) Dissolving an appropriate amount of cerium nitrate in water to obtain a cerium nitrate solution of a certain concentration;

[0013] (2) Shake the cerium nitrate solution obtained in step (1) and drop an appropriate amount of the shaken cerium nitrate solution into the porous fuel electrode of the solid oxide fuel cell and dry it;

[0014] (3) placing the porous fuel electrode dried in step (2) in a tubular furnace and calcining it into a CeO2 phase;

[0015] (4) Repeat steps (2) and (3) until the mass of CeO2 accounts for 2%-3% of the total mass of the battery.

[0016] Furthermore, the molar concentration of the cerium nitrate solution in step (1) is 0.1-1 mol / L.

[0017] Preferably, in step (1), the molar concentration of the cerium nitrate solution is 0.1 mol / L, and the water is deionized water.

[0018] Furthermore, the cerium nitrate in step (1) is cerium nitrate hexahydrate.

[0019] Furthermore, in step (2), the drying method is one of natural drying, vacuum drying, etc.; the vacuum drying time is 30-60 minutes.

[0020] Preferably, in step (2), the drying method is natural drying; the vacuum drying time is 30 minutes.

[0021] Preferably, the vacuum drying temperature is 50-60°C.

[0022] Furthermore, the calcination temperature in step (3) is 500-600°C.

[0023] Preferably, the calcination temperature in step (3) is 600°C.

[0024] Furthermore, the heating rate of the calcination in step (3) is 2-5°C / min.

[0025] Preferably, the heating rate of the calcination in step (3) is 5°C / min.

[0026] Furthermore, the calcination time in step (3) is 30 min-60 min.

[0027] Furthermore, the calcination time in step (3) is 30 minutes.

[0028] Preferably, the calcination time in step (3) is 1 hour.

[0029] Preferably, in step (4), the mass of CeO2 accounts for 3% of the total mass of the battery.

[0030] Furthermore, in step (4), after the temperature drops to room temperature after calcination, steps (2) and (3) are repeated.

[0031] The present invention provides a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by the preparation method.

[0032] The present invention also provides the application of a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by simple impregnation in hydrogen oxidation power generation or CO2 electrolysis reaction.

[0033] The high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode of the present invention has the advantages of simple preparation process, non-toxic and harmless preparation process, low preparation cost, strong universality of preparation method, flexible and controllable preparation process, large-scale batch production, and easy adjustment of the resulting battery components. The high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode prepared under the preferred conditions of the present invention has excellent H2O and CO2 co-electrolysis activity and high CH4 selectivity.

[0034] The high efficiency and high CH4 selectivity CeO2 modified Ni / BZCYYb obtained by the present invention is used as a porous fuel electrode, PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 3-δ (PBSCF) / BZCYYb as cathode, where PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 3-δ (δ refers to the non-stoichiometric number of oxygen). BZCYYb was used as the electrolyte to assemble a proton conductor solid oxide reversible battery, with an output power density of 663 mW cm at 600°C and 550°C. -2 and 438 mW cm -2 CO2 was introduced into the CeO2-modified Ni / BZCYYb porous fuel electrode at 550℃ and 892 mA / cm 2 and 1250 mA / cm 2 The voltages are only 1.42 V and 1.51 V at current densities of 1.5 and 2.5, respectively.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] 1. The present invention provides a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by simple impregnation, which has low raw material cost, low sintering temperature, low energy consumption in the production process, and low production cost.

[0037] 2. The present invention provides a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by simple impregnation. Its preparation method adopts a solution impregnation strategy and can be used to prepare composite porous fuel electrodes with different proportions of transition metal elements. It still has great development potential for different reactions.

[0038] 3. The present invention provides a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by simple impregnation. The preparation process is simple and easy, the preparation cycle is short, and it can be mass-produced, with commercial prospects.

[0039] 4. The present invention provides a proton conductor solid oxide reversible battery porous fuel electrode with high efficiency and high CH4 selectivity prepared by simple impregnation. The preparation process does not produce any toxic gas and is green, environmentally friendly and pollution-free.

[0040] 5. The high efficiency and high CH4 selectivity CeO2 modified Ni / BZCYYb obtained in this invention is used as a proton conductor solid oxide reversible battery with a porous fuel electrode. The output power density at 600℃ and 550℃ is 663 mW cm -2 and 438 mW cm -2 CO2 was introduced into the CeO2-modified Ni / BZCYYb porous fuel electrode at 550℃ and 892 mA / cm 2 and 1250 mA / cm 2 At current densities of 1.5 and 2.5 V, the voltages were only 1.42 V and 1.51 V, respectively, and the CH4 selectivity reached 16% and 17%. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a scanning electron microscope (SEM) image of Ni / BZCYYb and the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 1.

[0042] Figure 2 This is an X-ray energy spectrum (EDS) image of the porous fuel electrode of the high-efficiency, high CH4-selective proton conductor solid oxide reversible battery prepared by simple impregnation in Example 1.

[0043] Figure 3 The X-ray diffraction (XRD) pattern of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation of Ni, CeO2, and BZCYYb pure phase particles in Example 1.

[0044] Figure 4 This is a graph showing the volt-ampere characteristic curve (IV) of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 1 under the fuel cell mode.

[0045] Figure 5 This is the AC impedance spectrum of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 1 under the fuel cell.

[0046] Figure 6 This is a graph showing the volt-ampere characteristic curve (IV) of the porous fuel electrode of the proton conductor solid oxide reversible cell with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 2 in the CO2 and H2O co-electrolysis mode.

[0047] Figure 7 The electrochemical impedance spectroscopy (EIS) of the porous fuel electrode of the reversible proton conductor solid oxide cell with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 2 in the CO2 and H2O co-electrolysis mode.

[0048] Figure 8 This is a short-term stability diagram of the porous fuel electrode of the reversible proton conductor solid oxide cell with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 3 at different current densities in the CO2 and H2O co-electrolysis mode.

[0049] Figure 9 This is a bar chart of product selectivity at different current densities for the porous fuel electrode of the proton conductor solid oxide reversible cell with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 3 under the CO2 and H2O co-electrolysis mode.

[0050] Figure 10 This is a bar graph of the Faraday efficiency of the porous fuel electrode of the reversible proton conductor solid oxide cell with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 1 at different current densities in the CO2 and H2O co-electrolysis mode.

[0051] Figure 11 This is a current-voltage (IV) curve of the performance test of the unmodified proton conductor solid oxide reversible cell porous fuel electrode in comparative example 1 in fuel cell mode and electrolysis mode.

[0052] Figure 12 This is a bar chart showing the product selectivity of the unmodified proton conductor solid oxide reversible battery porous fuel electrode in Comparative Example 1. DETAILED DESCRIPTION

[0053] The following examples further illustrate the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are any processes not specifically described 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.

[0054] Example 1

[0055] (1) dissolving cerium nitrate in deionized water to obtain a cerium nitrate solution with a molar concentration of 0.1 mol / L;

[0056] (2) Shake the cerium nitrate solution obtained in step (1) and drop 8 μL of the shaken cerium nitrate solution into the porous fuel electrode (Ni / BZCYYb) of the solid oxide fuel cell using a pipette, and let it dry naturally for 30 minutes;

[0057] (3) The porous fuel electrode dried in step (2) was placed in a tubular furnace, heated to 600°C at a rate of 5°C / min, and calcined for 1 hour.

[0058] (4) After the calcination, the temperature is lowered to room temperature, and steps (2) and (3) are repeated 10 times until the mass of CeO2 (0.009 g) accounts for 3% of the total mass of the battery, thereby obtaining a high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

[0059] The scanning electron microscope (SEM) image of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity obtained in Example 1 is as follows: Figure 1 As shown in b), Figure 1 b) in the figure shows that compared with the smooth surface of BZCYYb (such as Figure 1 In a), the BZCYYb surface of the porous fuel electrode of the high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery obtained in Example 1 is uniformly coated with a layer of CeO2 particles.

[0060] The X-ray energy spectrum (EDS) imaging of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity obtained in Example 1 is as follows: Figure 2 As shown by Figure 2 It can be seen that the Ni and Ce elements in the porous fuel electrode of the obtained high-efficiency, high CH4-selective proton conductor solid oxide reversible battery do not overlap with each other, indicating that CeO2 is mainly coated on the smooth BZCYYb surface.

[0061] The X-ray diffraction (XRD) pattern of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity obtained in Example 1 is as follows: Figure 3 As shown, by comparing with the standard XRD card of Ni, the standard XRD card of CeO2 and the XRD of BZCYYb pure phase particles, it was found that three phases of Ni, BZCYYb and CeO2 existed in the porous fuel electrode of the obtained high efficiency and high CH4 selectivity proton conductor solid oxide reversible battery.

[0062] The performance of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 1 was tested in fuel cell mode. Fuel cell mode test conditions: Silver paste and ceramic sealant (Ceramabond 552) are used to seal the PCEC (proton ceramic electrochemical cell) to the glass tube. Silver grids are applied as current collectors on both electrodes of the battery. After heating the battery to 600°C, hydrogen is introduced into the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity obtained in Example 1 for reduction for 2 hours at a flow rate of 50 mL / min, and the oxygen electrode gas atmosphere is air. The volt-ampere characteristic curve and impedance spectrum of the battery are tested at 600°C and 550°C, as shown Figure 4 and Figure 5 All electrochemical tests were performed using the Zennium series electrochemical workstations from the German ZAHNER company.

[0063] Example 2

[0064] (1) dissolving cerium nitrate in deionized water to obtain a cerium nitrate solution with a molar concentration of 0.1 mol / L;

[0065] (2) Shake the cerium nitrate solution obtained in step (1) and drop 8 μL of the shaken cerium nitrate solution into the porous fuel electrode (Ni / BZCYYb) of the solid oxide fuel cell using a pipette, and let it dry naturally for 30 minutes;

[0066] (3) The porous fuel electrode dried in step (2) was placed in a tubular furnace, heated to 550°C at a rate of 2°C / min, and calcined for 30 minutes.

[0067] (4) After the calcination temperature drops to room temperature, repeat steps (2) and (3) 15 times until the mass of CeO2 (0.005g) accounts for 2% of the total mass of the battery, obtaining a high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

[0068] The scanning electron microscope (SEM) image of the high-efficiency, high CH4 selectivity proton conductor solid oxide reversible battery porous fuel electrode obtained in Example 2 is similar to that in Example 1. Compared with the smooth surface of BZCYYb, the BZCYYb surface of the high-efficiency, high CH4 selectivity proton conductor solid oxide reversible battery porous fuel electrode obtained is uniformly coated with a layer of CeO2 particles.

[0069] The X-ray energy spectrum (EDS) imaging of the porous fuel electrode of the high-efficiency, high CH4 selectivity proton conductor solid oxide reversible battery obtained in Example 2 is similar to that in Example 1. The Ni and Ce elements in the porous fuel electrode of the high-efficiency, high CH4 selectivity proton conductor solid oxide reversible battery obtained do not overlap with each other, indicating that CeO2 is mainly coated on the smooth BZCYYb surface.

[0070] The X-ray diffraction (XRD) pattern of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity obtained in Example 2 is similar to that in Example 1. Compared with the standard XRD card of Ni, the standard XRD card of CeO2 and the XRD of BZCYYb pure phase particles, it is found that three physical phases of Ni, BZCYYb and CeO2 exist in the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity.

[0071] The performance of the porous fuel electrode of the reversible proton conductor solid oxide battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 2 was tested in fuel cell mode. Fuel cell mode test conditions: Silver paste and ceramic sealant (Ceramabond 552) were used to seal the PCEC to the glass tube. Silver grids were applied as current collectors on both electrodes of the battery. After heating the battery to 600°C, hydrogen was introduced into the porous fuel electrode of the reversible proton conductor solid oxide battery with high efficiency and high CH4 selectivity obtained in Example 2 for 2 hours at a flow rate of 50 mL / min, and the oxygen electrode gas atmosphere was air. At 550°C, it was switched to electrolysis mode, and the gas on the fuel electrode side was switched to 2.6 mL / min of CO2 and 50 mL / min of argon, and the gas on the oxygen electrode side was switched to 20% (the ratio of the volume of H2O to the total volume of H2O and argon) H2O with argon (flow rate of 100 mL / min), and the current-voltage (IV) curve was obtained, as shown in FIG. Figure 6 The constant voltage electrochemical impedance spectroscopy (EIS) was measured at 550 °C in the frequency range of 100 kHz to 100 mHz, as shown in Figure 7 All electrochemical tests were performed using the Zennium series electrochemical workstations from the German ZAHNER company.

[0072] Example 3

[0073] (1) dissolving cerium nitrate in deionized water to obtain a cerium nitrate solution with a molar concentration of 0.5 mol / L;

[0074] (2) Shake the cerium nitrate solution obtained in step (1) and drop 8 μL of the shaken cerium nitrate solution into the porous fuel electrode (Ni / BZCYYb) of the solid oxide fuel cell using a pipette, and let it dry naturally for 30 minutes;

[0075] (3) The porous fuel electrode dried in step (2) was placed in a tubular furnace, heated to 500°C at a rate of 3°C / min, and calcined for 45 minutes.

[0076] (4) After the calcination, the temperature is lowered to room temperature, and steps (2) and (3) are repeated 8 times until the mass of CeO2 (0.008 g) accounts for 3% of the total mass of the battery, thereby obtaining a high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

[0077] The short-term stability test of the porous fuel cell for proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity prepared by simple impregnation in Example 3 was carried out. Figure 8 As shown. In the CO2 and H2O co-electrolysis mode, the high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode prepared in Example 3 showed high efficiency and stable performance under the application of current. During the period, the product content was analyzed using a Fuli GC97902 gas chromatograph. The product selectivity was calculated based on the test results, as shown in the figure. Figure 9 As shown. The calculated Faraday efficiency is as follows Figure 10 shown.

[0078] Comparative Example 1

[0079] (1) Add 4 g BZCYYb, 6 g NiO, 2 g corn starch and 6 g anhydrous ethanol into a ball mill, mill for 3 hours, and then dry under an infrared lamp for 3 hours to obtain porous fuel electrode powder;

[0080] (2) Take 0.3 g of the porous fuel electrode powder described in step (1) and press it into a disc with a diameter of 13 mm at a pressure of 5 MPa for 1 min;

[0081] (3) The porous fuel electrode disc obtained in step (2) was sintered at 1400° C. for 5 hours to obtain an unmodified proton conductor solid oxide reversible battery porous fuel electrode (Ni / BZCYYb).

[0082] The scanning electron microscope (SEM) image of the unmodified proton conductor solid oxide reversible battery porous fuel electrode obtained in Comparative Example 1 is as follows: Figure 1 As shown in a) in Figure 1 As can be seen from a) in the figure, the unmodified proton conductor solid oxide reversible battery porous fuel electrode has a smooth surface without particle coating.

[0083] The X-ray diffraction (XRD) pattern of the unmodified proton conductor solid oxide reversible battery porous fuel electrode obtained in Comparative Example 1 is as follows: Figure 3As shown, the unmodified proton conductor solid oxide reversible battery porous fuel electrode contains two phases, Ni and BZCYYb, but no CeO2 phase.

[0084] The unmodified proton conductor solid oxide reversible cell porous fuel electrode obtained in Comparative Example 1 was tested for performance in fuel cell mode. Fuel cell mode test conditions: Silver paste and ceramic sealant (Ceramabond 552) were used to seal the PCEC to the glass tube. Silver grids were applied as current collectors on both electrodes of the cell. After heating the cell to 600°C, hydrogen was introduced into the fuel electrode for reduction for 2 hours at a flow rate of 50 mL / min, and the oxygen electrode gas atmosphere was air. A current-voltage (IV) curve was obtained. After the temperature was lowered to 550°C, hydrogen was introduced into the fuel electrode for reduction for 2 hours at a flow rate of 50 mL / min, and the oxygen electrode gas atmosphere was air. Another current-voltage (IV) curve was obtained, as shown in FIG. Figure 11 As shown in A in the figure. At 550°C, the electrolysis mode was switched to 2.6 mL / min CO2 and 50 mL / min argon on the fuel electrode side, and the gas on the oxygen electrode side was switched to argon containing 20% ​​(the ratio of the volume of H2O to the total volume of H2O and argon) H2O (flow rate 100 mL / min). The current-voltage (IV) curve was obtained, as shown in Figure 1. Figure 11 As shown in Figure B. All electrochemical tests were performed using the Zennium series electrochemical workstations from the German ZAHNER company.

[0085] The unmodified proton conductor solid oxide reversible battery porous fuel electrode obtained in Comparative Example 1 was subjected to product content analysis in the CO2 and H2O co-electrolysis mode. The testing instrument was a Fuli GC97902 gas chromatograph. The product selectivity was calculated based on the test results, as shown in FIG. Figure 12 shown.

[0086] Effect analysis

[0087] Combine Figure 1 、 Figure 2 and Figure 3 The results show that the embodiment of the present invention can modify the target active element CeO2 uniformly and densely on the BZCYYb surface through a simple impregnation method, and prepare a high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

[0088] Combine Figure 4 and Figure 5 The results show that the high-efficiency and high-CH4-selective proton conductor solid oxide reversible battery prepared in the embodiment of the present invention has excellent output power in fuel cell mode, with output power densities of 663 mW cm at 600°C and 550°C, respectively. -2and 438 mW cm -2 , and the impedance is 0.5 Ω cm -2 and 1 Ω cm -2 .

[0089] Combine Figure 8 、 Figure 9 The results show that the high efficiency and high CH4 selectivity proton conductor solid oxide reversible battery prepared in the embodiment of the present invention has excellent electrolysis performance in the CO2 and H2O co-electrolysis mode, with a power of 892 mA / cm at 550 °C. 2 The voltage is only 1.42V at a current density of 1250 mA / cm 2 The voltage is only 1.51V at a current density of 1.5V, and the polarization resistance is only 0.01 Ωcm -2 There is no obvious performance degradation during the 80 min test, while at 550℃, 892 mA / cm 2 The electrolysis voltage of the unmodified Ni / BZCYYb porous fuel electrode was 1.47 V at a current density of 1250 mA / cm 2 The electrolysis voltage of the unmodified Ni / BZCYYb porous fuel electrode is 1.59 V at a current density of 892 mA / cm 2 At higher currents, the CH4 selectivity is significantly improved, 892 mA / cm 2 and 1250 mA / cm 2 At current densities of 1000 nm and 1000 nm, the CH4 selectivity reached 16% and 17%, indicating that CeO2 has a positive effect on driving protons for deep CO2 hydrogenation at high currents. Figure 10 ) showed that the Faradaic efficiency of the high-efficiency, high CH4-selective proton conductor solid oxide reversible battery prepared by simple impregnation reached more than 60%, proving its high energy conversion efficiency.

[0090] Combine Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 11 、 Figure 12 The results show that the embodiment of the present invention prepares a high-efficiency, high CH4-selective proton conductor solid oxide reversible battery by simple impregnation, which has completely improved electrochemical performance and excellent hydrogen and oxygen production performance compared with Comparative Example 1. In the electrolysis mode, the high current density has a 5-fold increase in CH4 selectivity.

Claims

1. A method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity, characterized in that: The steps include: (1) dissolving cerium nitrate in water to obtain a cerium nitrate solution; the molar concentration of the cerium nitrate solution is 0.1-1 mol / L; (2) Shake the cerium nitrate solution obtained in step (1) and drop the shaken cerium nitrate solution into the Ni / BZCYYb porous fuel electrode of the solid oxide fuel cell, where BZCYYb is BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ , δ is the non-stoichiometric number of oxygen, dry; (3) placing the porous fuel electrode dried in step (2) in a tubular furnace and calcining it into a CeO2 phase; the heating rate of the calcination is 2-5°C / min; the calcination temperature is 500-600°C; and the calcination time is 30-60min; (4) Repeat steps (2) and (3) until the mass of CeO2 accounts for 2%-3% of the total mass of the battery, thereby obtaining a highly efficient, highly CH4-selective proton conductor solid oxide reversible battery porous fuel electrode.

2. The method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity according to claim 1, characterized in that: In step (2), the drying method is one of natural drying and vacuum drying.

3. The method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity according to claim 2, characterized in that: The vacuum drying time is 30-60 min.

4. The method for preparing a porous fuel electrode of a proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity according to claim 1, characterized in that: In step (4), after the calcination, the temperature drops to room temperature and then steps (2) and (3) are repeated.

5. A high-efficiency, high-CH4-selective proton conductor solid oxide reversible battery porous fuel electrode prepared by the preparation method according to any one of claims 1 to 4.

6. Application of the porous fuel electrode of the proton conductor solid oxide reversible battery with high efficiency and high CH4 selectivity as described in claim 5 in hydrogen oxidation power generation or CO2 electrolysis reaction.

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