An RP type thin film and a preparation method and application thereof
Patent Information
- Application Number
- CN202311822734.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2026-09-04
- Estimated Expiration
- 2043-12-27
AI Technical Summary
然而，当用粉末材料制作SOFC电极时，环境和经验因素对电池性能的影响很大，导致多次测量的重复性比较低
[0024] Compared with the prior art, the beneficial effects of the present invention are: the present invention uses PLD and in-situ precipitation methods to prepare RP structure thin films, and in-situ precipitates A-site and B-site metal oxide nanoparticles on the film surface, effectively improving its electrochemical performance, and with unreduced Pr3Ni2O 7+δ Compared to thin films, Pr3Ni2O after hydrogen reduction at 600℃ for 5 hours... 7+δ The thin film polarization resistance was reduced by nearly 70%, and the in-situ precipitated PrO x The uniform distribution of NiO nanoparticles on the film surface increases the specific surface area, increases the number of reactive sites, effectively promotes the adsorption of oxygen on the surface, and thus improves the electrochemical performance.
Smart Images
Figure CN117766785B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of RP thin film technology, and in particular to an RP-type thin film, its preparation method, and its application. Background Technology
[0002] Ruddlesden-Popper (RP) type compounds are perovskite-like structures with the general chemical formula A. n+1 B n O 3n+1 Compared to the traditional perovskite structure, A n+1 B n O 3n+1 The crystal structure of RP-structured compounds consists of alternating ABO3 and A2O2 layers. The ABO3 layers generate numerous interstitial oxygen atoms and vacancies, resulting in a high oxygen diffusion coefficient and excellent oxygen ion transport performance. Simultaneously, the ABO3 layers exhibit good electron transport properties, thus RP-structured compounds possess mixed ion-electron conductivity. Furthermore, they exhibit a low coefficient of thermal expansion and good mechanical compatibility with traditional solid electrolyte materials. Overall, RP-structured compounds possess excellent comprehensive performance and have become a research hotspot for electrode materials in intermediate-temperature solid oxide fuel cells (SOFCs) in recent years. Synthesis methods for RP-structured compounds are mature, commonly including solid-state and sol-gel methods, yielding powder products. However, when using powder materials to fabricate SOFC electrodes, environmental and empirical factors significantly influence battery performance, leading to low repeatability in multiple measurements. Additionally, the electrochemical performance of RP-structured perovskite-like oxides as SOFC cathode materials requires further improvement. Summary of the Invention
[0003] This invention solves the problems in related technologies, proposing an RP-type thin film, its preparation method, and its application. Using PLD technology and in-situ precipitation, an RP-structured thin film is prepared, and A-site and B-site metal oxide nanoparticles are precipitated in situ on the film surface, effectively improving its electrochemical performance, and interacting with unreduced Pr3Ni2O. 7+δ Compared to thin films, Pr3Ni2O after hydrogen reduction at 600℃ for 5 hours... 7+δ The thin film polarization resistance was reduced by nearly 70%, and the in-situ precipitated PrO x The uniform distribution of NiO nanoparticles on the film surface increases the specific surface area, increases the number of reactive sites, effectively promotes the adsorption of oxygen on the surface, and thus improves the electrochemical performance.
[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:
[0005] An RP-type thin film, with the general chemical formula: Pr3Ni2O 7+δ@PrO x / NiO.
[0006] In another aspect, the present invention provides a method for preparing an RP-type thin film, the specific steps of which are as follows:
[0007] S1. Target preparation: Pr6O 11 Ni(NO)3·6H2O powder was dissolved in nitric acid to obtain a nitrate solution. Citric acid and polyethylene glycol were added as chelating agents to obtain a mixed solution. This solution was then subjected to water bath evaporation, calcination, grinding, first sintering, annealing, dry pressing, cold isostatic pressing, and a second sintering to obtain a dense target material, Pr3Ni2O. 7+δ ;
[0008] S2, Preparation of Pr3Ni2O 7+δ Thin film: Using a YSZ(100) single crystal substrate as the substrate, the target material Pr3Ni2O in step S1 was subjected to thin film treatment. 7+δ Pr3Ni2O prepared by PLD method 7+δ film;
[0009] S3, Pr3Ni2O 7+δ Thin film surface modification: Pr3Ni2O in S2 7+δ The membrane was placed in a closed tube furnace and reduced in an atmosphere of H2 / Ar mixture for 1 hour and 5 hours at a temperature of 600–900°C.
[0010] As a preferred embodiment, the specific steps for preparing the target material in step S1 are as follows:
[0011] S11, Pr6O 11 Pre-treat at 1000℃ for 10h, then dissolve in concentrated nitric acid to form a nitrate solution; add Ni(NO)3·6H2O powder to the nitrate solution to form a nitrate mixture, then add citric acid and polyethylene glycol as chelating agents to the nitrate mixture under stirring to obtain a mixed solution;
[0012] S12. Transfer the mixed solution to a water bath and evaporate it at 90°C until the solution becomes a gel.
[0013] S13. Heat the obtained gel to 350°C on an electric furnace and calcine for 30 minutes to obtain the crude precursor powder of the target material.
[0014] S14. The crude precursor powder is ground thoroughly in a mortar for 30 minutes, then sintered in a tube furnace at 600°C for 10 hours, followed by sintering at 900°C for another 10 hours, and finally annealed at 1300°C for 10 hours to obtain pure-phase Pr3Ni2O.7+δ powder;
[0015] S15, Pr3Ni2O 7+δ The powder was placed into a mold, dry-pressed at 36 MPa and held for 5 minutes, and then cold isostatically pressed at 270 MPa and held for 15 minutes.
[0016] S16. Place the pressed target material in a tube furnace, heat it to 1300℃ at a heating rate of 1℃ / min, hold it at that temperature for 24 hours, then cool it down to 500℃ at a cooling rate of 1.5℃ / min, and allow it to cool naturally to obtain a dense target material Pr3Ni2O. 7+δ .
[0017] As a preferred embodiment, in step S11, the mass fraction of concentrated nitric acid is 68%, and Pr6O 11 The molar ratio of citric acid to Ni(NO)3·6H2O is 1:4, and the molar ratio of citric acid, polyethylene glycol to total metal ions is 1.5:1:1.
[0018] As a preferred method, Pr3Ni2O is prepared by PLD. 7+δ The specific steps for thin film are as follows:
[0019] S21. Use a 10×10×0.5mm YSZ(100) single crystal substrate as the substrate. Before use, the YSZ(100) substrate is ultrasonically cleaned in acetone, ethanol and deionized water for 10 minutes in sequence.
[0020] S22, YSZ(100) substrate and Pr3Ni2O 7+δ The target material is placed in the PLD vacuum chamber and evacuated to 10. -6 Torr uses a KrF excimer laser with a wavelength of 248 nm, a pulse frequency of 8 Hz, a deposition temperature of 900 °C, a target-substrate distance of 5 cm, a deposition oxygen pressure of 10 mTorr, and deposits 4080 pulses with a pulse energy of ~450 mJ.
[0021] S23. Under annealing oxygen pressure of 10 Torr, cool to 250°C at a cooling rate of 5°C / min, and then allow to cool naturally to room temperature to obtain Pr3Ni2O. 7+δ film.
[0022] As a preferred option, in step S3, before reduction, Pr3Ni2O is first... 7+δ The membrane surface was cleaned sequentially with acetone, anhydrous ethanol and deionized water, dried and then placed in a closed tube furnace; the volume fraction of H2 in the H2 / Ar mixture was 5%.
[0023] A final aspect of the invention also provides the application of an RP-type thin film in a solid oxide fuel cell cathode.
[0024] Compared with the prior art, the beneficial effects of the present invention are: the present invention uses PLD and in-situ precipitation methods to prepare RP structure thin films, and in-situ precipitates A-site and B-site metal oxide nanoparticles on the film surface, effectively improving its electrochemical performance, and with unreduced Pr3Ni2O 7+δ Compared to thin films, Pr3Ni2O after hydrogen reduction at 600℃ for 5 hours... 7+δ The thin film polarization resistance was reduced by nearly 70%, and the in-situ precipitated PrO x The uniform distribution of NiO nanoparticles on the film surface increases the specific surface area, increases the number of reactive sites, effectively promotes the adsorption of oxygen on the surface, and thus improves the electrochemical performance. Attached Figure Description
[0025] Figure 1 This invention is Pr3Ni2O 7+δ XRD pattern of the target material;
[0026] Figure 2 These are the HRXRD patterns of the thin films of the present invention after hydrogen reduction for 5 hours at different temperatures;
[0027] Figure 3 These are SEM images of the thin films of the present invention after hydrogen reduction for 5 hours at different temperatures.
[0028] Figure 4 These are the HRXRD patterns of the thin films of the present invention after hydrogen reduction for 1 hour at different temperatures;
[0029] Figure 5 These are SEM images of the thin films of the present invention after hydrogen reduction for 1 hour at different temperatures.
[0030] Figure 6 The present invention compares the polarization resistance of the half-cells, including (a) polarization resistance values after hydrogen reduction for 5 hours at different temperatures, (b) polarization resistance values after hydrogen reduction for 1 hour at different temperatures, (c) impedance spectrum after hydrogen reduction for 5 hours at 600°C, and (d) impedance spectrum after hydrogen reduction for 1 hour at 700°C.
[0031] Figure 7 This invention relates to the EDS energy dispersive spectroscopy analysis of the thin film surface after hydrogen reduction at 600℃ for 5 hours. Detailed Implementation
[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0034] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.
[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.
[0036] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.
[0037] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.
[0038] Example 1
[0039] An RP-type thin film, whose general chemical formula is: Pr3Ni2O 7+δ @PrO x / NiO.
[0040] Example 2
[0041] In another aspect, the present invention provides a method for preparing an RP-type thin film, the specific steps of which are as follows:
[0042] S1. Preparation of the target material:
[0043] S11, Pr6O 11 Pretreated at 1000℃ for 10h to remove impurities, then dissolved in 68% concentrated nitric acid to form a nitrate solution; Ni(NO)3·6H2O powder was added to the above nitrate solution, and then citric acid and polyethylene glycol were added as chelating agents to the nitrate mixture under stirring (about 30min) to obtain a mixed solution, wherein Pr6O 11 The molar ratio of citric acid to Ni(NO)3·6H2O is 1:4, and the molar ratio of citric acid, polyethylene glycol to total metal ions is 1.5:1:1.
[0044] S12. Transfer the mixed solution to a water bath, set the temperature to 90°C, and evaporate in the water bath (generally requiring more than 12 hours) until the solution becomes a gel state.
[0045] S13. Heat the obtained gel to 350°C on an electric furnace and calcine for 30 minutes to remove most of the organic matter, thereby obtaining the crude precursor powder of the target material.
[0046] S14. The crude precursor powder is placed in a mortar and ground thoroughly for 30 minutes. Then, it is sintered in a tube furnace at 600°C for 10 hours, followed by sintering at 900°C for another 10 hours to remove residual organic matter. Finally, it is annealed at 1300°C for 10 hours to obtain pure-phase Pr3Ni2O. 7+δ powder;
[0047] S15, Pr3Ni2O 7+δ The powder was placed into a 1-inch mold, dry-pressed at 36 MPa and held for 5 minutes, and then cold isostatically pressed at 270 MPa and held for 15 minutes.
[0048] S16. Place the pressed 1-inch target material in a tube furnace, heat it to 1300℃ at a heating rate of 1℃ / min, hold it at that temperature for 24 hours, then cool it down to 500℃ at a cooling rate of 1.5℃ / min, and allow it to cool naturally to obtain a dense target material Pr3Ni2O. 7+δ The X-ray diffraction (XRD) characterization results of the crystal structure of the target material are as follows: Figure 1 As shown in the XRD pattern, Pr3Ni2O 7+δ The typical RP structure, belonging to the Fmmm (No. 69) space group, with no other impurity peaks, indicates that Pr3Ni2O 7+δ The target material is a pure phase.
[0049] S2, Preparation of Pr3Ni2O 7+δ film:
[0050] S21. Use a 10×10×0.5mm YSZ(100) single crystal substrate as the substrate. Before use, the YSZ(100) substrate is ultrasonically cleaned in acetone, ethanol and deionized water for 10 minutes to remove organic matter or oxides and other impurities adhering to the surface of the substrate.
[0051] S22, YSZ(100) substrate and Pr3Ni2O 7+δ The target material is placed in the PLD vacuum chamber and evacuated to 10. -6 Torr uses a KrF excimer laser with a wavelength of 248 nm, a pulse frequency of 8 Hz, a deposition temperature of 900 °C, a target-substrate distance of 5 cm, a deposition oxygen pressure of 10 mTorr, and deposits 4080 pulses with a pulse energy of ~450 mJ.
[0052] S23. Under annealing oxygen pressure of 10 Torr, cool to 250°C at a cooling rate of 5°C / min, and then allow to cool naturally to room temperature to obtain Pr3Ni2O. 7+δ The thin film, Pr3Ni2O, was measured using a profilometer. 7+δ The thickness of the thin film is approximately 100 nm;
[0053] S3, Pr3Ni2O 7+δ Thin film surface modification:
[0054] Pr3Ni2O in S2 7+δ The film surface was cleaned sequentially with acetone, anhydrous ethanol and deionized water, dried and then placed in a closed tube furnace for reduction treatment in an atmosphere of H2 / Ar mixed gas (H2 volume fraction of 5%) for 5 hours at a temperature of 600℃.
[0055] Example 3
[0056] Unlike Example 2, the reduction temperature in step S3 is 700°C.
[0057] Example 4
[0058] Unlike Example 2, the reduction temperature in step S3 is 800°C.
[0059] Example 5
[0060] Unlike Example 2, the reduction temperature in step S3 is 900°C.
[0061] In Examples 2 to 5, the thin film samples were reduced at different temperatures for 5 hours. The reduced thin film samples were then characterized using high-resolution X-ray diffraction (HRXRD) in 2θ-ω scanning mode. The HRXRD results are shown below. Figure 2 As shown, by Figure 2 It can be seen that, in its unreduced state, Pr3Ni2O 7+δ The thin film was epitaxially grown along the YSZ substrate; after reduction at different temperatures for 5 h, PrOx (oxide of Pr) and NiO phases were precipitated in all cases. Figure 3 Comparison of SEM morphology before and after hydrogen reduction for 5 hours at different temperatures reveals that fine nanoparticles are uniformly distributed on the surface of the film after hydrogen reduction.
[0062] Example 6
[0063] Unlike Example 2, the reduction process in step S3 takes 1 hour;
[0064] Example 7
[0065] Unlike Example 6, the reduction temperature in step S3 is 700°C.
[0066] Example 8
[0067] Unlike Example 6, the reduction temperature in step S3 is 800°C.
[0068] Example 9
[0069] Unlike Example 6, the reduction temperature in step S3 is 900°C.
[0070] In Examples 6 to 9, the HRXRD results after reduction at different temperatures for 1 hour are as follows: Figure 4 As shown, the surface morphology is as follows Figure 5 As shown; by Figure 4 and Figure 5 It can be seen that PrO precipitates after reduction at different temperatures for 1 hour. x (Oxides of Pr) and NiO phase.
[0071] Example 10
[0072] A final aspect of the invention also provides the application of an RP-type thin film in a solid oxide fuel cell cathode.
[0073] The in-situ deposited nanoparticle films prepared in Examples 2 to 9 were used as cathodes to fabricate SOFC half-cells. The impedance spectra of the half-cells were measured to obtain the cathode polarization resistance, thereby determining the optimal in-situ deposition temperature and time. The electrochemical impedance spectroscopy test results are as follows: Figure 6 As shown.
[0074] Depend on Figure 6 It can be seen that at the half-cell test temperature of 650℃, the hydrogen reduction temperature is 600℃ and the reduction time is 5h, which can reduce the polarization resistance by nearly 70%. Therefore, from the half-cell test results, it can be seen that the optimal hydrogen reduction temperature is 600℃ and the optimal reduction time is 5h.
[0075] like Figure 7 As shown, energy dispersive spectroscopy (EDS) analysis was performed on the sample with the best electrochemical performance. After reduction, Pr and Ni oxides were uniformly distributed on the film surface, and the Ni / Pr ratio was higher than that of Pr3Ni2O. 7+δ The increased stoichiometry indicates that the increased surface NiO content is beneficial for improving the catalytic activity of the electrode material. In summary, hydrogen reduction treatment of the film can significantly improve the electrochemical performance of the RP structure film, exhibiting excellent performance at medium and low temperatures. Therefore, using PLD technology to prepare the film and employing in-situ precipitation for surface modification is an effective way to improve the electrochemical performance of Pr3Ni2O. 7+δ Methods for assessing the electrochemical properties of thin films.
[0076] The above are preferred embodiments of the present invention. Those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions or modifications made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims
1. A method for preparing an RP-type thin film, characterized in that, The specific steps are as follows: S1. Preparation of the target material: Pr6O 11 Ni(NO)3·6H2O powder was dissolved in nitric acid to obtain a nitrate solution. Citric acid and polyethylene glycol were added as chelating agents to obtain a mixed solution. This solution was then subjected to water bath evaporation, calcination, grinding, first sintering, annealing, dry pressing, cold isostatic pressing, and a second sintering to obtain a dense target material, Pr3Ni2O. 7+δ ; S2, Preparation of Pr3Ni2O 7+δ Thin film: Pr3Ni2O was prepared by PLD method using YSZ(100) single crystal substrate as substrate. 7+δ film; S3, Pr3Ni2O 7+δ Thin film surface modification: Pr3Ni2O in S2 7+δ The membrane was placed in a closed tube furnace and reduced in an atmosphere of H2 / Ar mixture for 1 hour and 5 hours at a temperature of 600~900℃.
2. The method for preparing RP-type thin films according to claim 1, characterized in that: In step S1, the specific steps for preparing the target material are as follows: S11, Pr6O 11 Pretreated at 1000℃ for 10 h, then dissolved in concentrated nitric acid to form a nitrate solution; Ni(NO)3·6H2O powder was added to the nitrate solution to form a nitrate mixture, and then citric acid and polyethylene glycol were added as chelating agents to the nitrate mixture under stirring to obtain a mixed solution; S12. Transfer the mixed solution to a water bath and evaporate it at 90°C until the solution becomes a gel. S13. Heat the obtained gel to 350°C on an electric furnace and calcine for 30 minutes to obtain the crude precursor powder of the target material. S14. The crude precursor powder is ground thoroughly in a mortar for 30 minutes, then sintered in a tube furnace at 600°C for 10 hours, followed by sintering at 900°C for another 10 hours, and finally annealed at 1300°C for 10 hours to obtain pure-phase Pr3Ni2O. 7+δ powder; S15, Pr3Ni2O 7+δ The powder was placed into a mold, dry-pressed at 36 MPa and held for 5 minutes, and then cold isostatically pressed at 270 MPa and held for 15 minutes. S16. Place the pressed target material in a tube furnace, heat it to 1300℃ at a heating rate of 1℃ / min, hold it at that temperature for 24 hours, then cool it down to 500℃ at a cooling rate of 1.5℃ / min, and allow it to cool naturally to obtain a dense target material Pr3Ni2O. 7+δ .
3. The method for preparing RP-type thin films according to claim 2, characterized in that: In step S11, the mass fraction of concentrated nitric acid is 68%, and Pr6O 11 The molar ratio of citric acid to Ni(NO)3·6H2O is 1:4, and the molar ratio of citric acid, polyethylene glycol to total metal ions is 1.5:1:
1.
4. The method for preparing RP-type thin films according to claim 1, characterized in that: Pr3Ni2O prepared by PLD method 7+δ The specific steps for thin film are as follows: S21. Use a 10×10×0.5mm YSZ(100) single crystal substrate as the substrate. Before use, the YSZ(100) substrate is ultrasonically cleaned in acetone, ethanol and deionized water for 10 minutes in sequence. S22, YSZ(100) substrate and Pr3Ni2O 7+δ The target material is placed in the PLD vacuum chamber and evacuated to 10. -6 Torr uses a KrF excimer laser with a wavelength of 248 nm, a pulse frequency of 8 Hz, a deposition temperature of 900 °C, a target-substrate distance of 5 cm, a deposition oxygen pressure of 10 mTorr, and deposits 4080 pulses with a pulse energy of ~450 mJ. S23. Under annealing oxygen pressure of 10 Torr, the sample was cooled to 250°C at a cooling rate of 5°C / min, and then allowed to cool naturally to room temperature to obtain Pr3Ni2O. 7+δ film.
5. The method for preparing RP-type thin films according to claim 1, characterized in that: In step S3, before reduction, Pr3Ni2O is first... 7+δ The membrane surface was cleaned sequentially with acetone, anhydrous ethanol and deionized water, dried and then placed in a closed tube furnace; the volume fraction of H2 in the H2 / Ar mixture was 5%.
6. The application of an RP-type thin film prepared by the method described in any one of claims 1 to 5 in a solid oxide fuel cell cathode.