A Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder

Abstract

The present invention discloses a Zr 0.786 Y 0.214 O 1.866‑δ @BaZr 0.78 Y 0.22 O 3‑δ Nano powder belongs to the technical field of solid electrolyte materials. The present invention prepares Zr 0.786 Y 0.214 O 1.866‑δ For the core, BaZr 0.78 Y 0.22 O 3‑δ Zr for the shell 0.786 Y 0.214 O 1.866‑δ @BaZr 0.78 Y 0.22 O 3‑δ The nanopowder with a viscosity of (δ=0.1~0.5) increases the interface ratio of the YDZ phase and the BZY phase, improves the continuity of the interface between the two phases, constructs a large number of ion conductive channels to further improve the conductivity of the nanopowder, solves the problems of interface separation and discontinuity between the YDZ phase and the BZY phase prepared by the traditional mechanical mixing method, and uneven distribution of the second phase, and realizes the continuity and conduction of the second phase / ZrO2 interface, thereby avoiding the problem of particle dispersion when the two powders are prepared separately and then mixed and the disadvantage of discontinuity of the two-phase interface.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid electrolyte materials, and specifically relates to a Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder. Background Art

[0002] Compared with other oxide materials, ZrO2 has good electrical conductivity at high temperatures, good thermal stability and chemical stability, and can be used as a candidate material for solid oxide fuel cell electrolytes. The application research and development of proton conductor oxides in the synthesis of low-temperature solid oxide fuel cells has received great attention. Some ABO3-type perovskite oxides have high proton conductivity in hydrogen or water atmospheres. Typical materials include BaCeO3-based and BaZrO3-based proton conductor oxides with larger A-site cations. Among them, barium zirconate perovskite structure is a cubic phase with good mechanical properties and a high melting point (2700°C). It is more stable in the medium temperature range of 400-700°C and does not react with acidic gases such as CO2, SO2 and water vapor. Current research shows that the ZrO2 / BaZrO3 composite can improve the conductivity of the material, mainly because the interface between the ZrO2 / BaZrO3 phases can serve as a H + and O 2- The high-speed channel improves the electrical conductivity. However, the improvement in its conductivity is not obvious, mainly because after the mechanical mixing method is used to introduce the BaZrO3 second phase, the interface between ZrO2 / BaZrO3 is isolated and discontinuous. The second phase grains exist in isolation, and the two-phase interface cannot be interconnected to form a network. Although the conductivity of the introduced two-phase interface is very high, it is still blocked by the low-conductivity ZrO2 grains, and the overall conductivity of the composite ceramic cannot be significantly improved. In addition, the traditional mechanical mixing method to introduce the second phase to obtain composite ceramics also has the problems of second phase agglomeration and uneven distribution. Summary of the Invention

[0003] In view of the above shortcomings of the prior art, the present invention provides a Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A Zr 0.786 Y 0.214 O1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, improve the conductivity of the material by regulating the material structure and preparation method; Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowders of Zr 0.786 Y 0.214 O 1.866-δ For the core, BaZr 0.78 Y 0.22 O 3-δ is the outer shell, where δ = 0.1~0.5.

[0006] The Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ The preparation method of nanopowder comprises the following steps:

[0007] (1) Zr(CH3COO)4, Y(NO3)3·6H2O and citric acid were added to water to prepare a core precursor aqueous solution, and then ammonia was added to adjust the pH of the solution and stirred, and then ultrasonically dispersed to obtain suspension A;

[0008] (2) Ba(COOCH3)2, Zr(CH3COO)4, Y(NO3)3·6H2O and sodium dodecylbenzenesulfonate were added to water to prepare a shell precursor aqueous solution and stirred to prepare solution B;

[0009] (3) Suspension A and solution B were mixed, ammonia was added to adjust the pH, and the mixture was stirred. The mixture was then ultrasonically dispersed and filtered to obtain precipitate C.

[0010] (4) After washing, drying and calcining the precipitate C, Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Core-shell structured nanopowders.

[0011] The present invention uses BaZr 0.78 Y 0.22 O 3-δ Proton conductor as shell effectively solves the problem of restricting the core Zr 0.786 Y 0.214 O 1.866-δTo solve the problem of extremely low grain boundary conductivity of ionic conductors, proton conductors and ionic conductors are combined to synergistically improve the conductivity of the material.

[0012] As a preferred embodiment of the present invention, the molar ratio of Zr(CH3COO)4, Y(NO3)3·6H2O and citric acid is 0.8:(0.1-0.2):(0.1-0.15).

[0013] As a preferred embodiment of the present invention, the molar ratio of Ba(COOCH3)2, Zr(CH3COO)4, Y(NO3)3·6H2O and sodium dodecylbenzenesulfonate is (1-1.6):0.8:(0.1-0.2):(0.1-0.15).

[0014] The present invention uses citric acid and sodium dodecylbenzenesulfonate to modify Zr 0.786 Y 0.214 O 1.866-δ Ionic conductors, on the one hand, synergistically promote the formation of core-shell structure and enhance the 0.786 Y 0.214 O 1.866-δ Ionic conductors and BaZr 0.78 Y 0.22 O 3-δ The interfacial continuity of the proton conductor builds ion conduction channels, improving the material's conductivity. Without citric acid, the prepared nanopowder material exhibits uneven morphology, severe agglomeration, and uneven size, with some non-core-shell structures appearing, and the material's conductivity significantly decreases. Without sodium dodecylbenzenesulfonate, the material exhibits poor dispersibility, weak chemical bonding between the core and shell, and deteriorated mechanical properties, leading to a decrease in conductivity.

[0015] As a preferred embodiment of the present invention, the concentration of the core precursor in the core precursor aqueous solution is 0.1 to 1 mol / L, and the concentration of the shell precursor in the shell precursor aqueous solution is 0.3 to 1.5 mol / L.

[0016] As a preferred embodiment of the present invention, in step (3), the volume ratio of suspension A to solution B is (0.5-1):1.

[0017] As a preferred embodiment of the present invention, the pH in step (1) is 8-10.

[0018] As a preferred embodiment of the present invention, the pH in step (3) is 9-10.

[0019] As a preferred embodiment of the present invention, the calcination temperature is 950° C. and the calcination time is 4 hours.

[0020] Compared with the prior art, the present invention has the following beneficial effects: the present invention prepares Zr0.786 Y 0.214 O 1.866-δ As the core, BaZr 0.78 Y 0.22 O 3-δ YDZ@BZY core-shell nanopowder with an outer shell, which increases the 0.786 Y 0.214 O 1.866-δ Phase and BaZr 0.78 Y 0.22 O 3-δ The interface ratio of the phases is improved, the continuity of the two-phase interface is improved, a large number of ion conductive channels are constructed, the conductivity of the nanopowder is further improved, and the conductivity of the composite electrolyte of the dual ion conductor (core ion conductor shell proton conductor) is improved. The interface separation and discontinuity between the YDZ phase and the BZY phase prepared by the traditional mechanical mixing method, as well as the uneven distribution of the second phase, are solved, and the continuity and conduction of the second phase / ZrO2 interface are achieved, thereby avoiding the problem of particle dispersion when the two powders are prepared separately and then mixed and the disadvantage of discontinuity of the two-phase interface. In addition, the present invention prepares BaZr by coprecipitation. 0.78 Y 0.22 O 3-δ The shell can effectively reduce the agglomeration of powders during the reaction process, maintain a smaller particle size, and allow various metal elements to precipitate at the same time, making the composition more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Flow chart of the preparation of nanopowders.

[0022] Figure 2 The Zr prepared in Example 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ TEM and HRTEM images of nanopowders; Figure (a) is the surface morphology image; (b) is the HRTEM image of the core; (c) is the HRTEM image of the shell.

[0023] Figure 3 The Zr prepared in Example 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δSEM image of a single particle of nanopowder; Figure (a) is the morphology image; (b) is the EDS image of the Ba element.

[0024] Figure 4 The Zr prepared in Example 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ SEM image of nanopowder.

[0025] Figure 5 Zr prepared in Comparative Example 3 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ SEM image of nanopowder.

[0026] Figure 6 The Zr prepared in Example 2 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ SEM image of nanopowder.

[0027] Figure 7 The Zr prepared in Example 3 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ SEM image of nanopowder.

[0028] Figure 8 The Zr prepared in Example 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ XRD pattern of nanopowder.

[0029] Figure 9 Zr prepared in Comparative Example 3 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ XRD pattern of nanopowder.

[0030] Figure 10 The Zr prepared in Example 1 0.786 Y0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ AC impedance diagram of ceramics.

[0031] Figure 11 The Zr prepared in Example 2 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ AC impedance diagram of ceramics.

[0032] Figure 12 The Zr prepared in Comparative Example 5 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ AC impedance diagram of ceramics.

[0033] Figure 13 This is the AC impedance diagram of the YDZ / BZY composite ceramic prepared in Comparative Example 6. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] Example 1

[0036] A Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ (δ=0.1) The preparation method of nano powder comprises the following steps:

[0037] (1) Prepare Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O) with a concentration of 0.1 mol / L according to the molar ratio of Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O)=0.8:0.1:0.1. 0.786 Y 0.214 O 1.866-δ The core precursor aqueous solution was then added with ammonia water to adjust the pH of the solution to 8, and the solution was stirred with a magnetic stirrer for 2 hours, and then ultrasonically dispersed with an ultrasonic cleaner for 30 minutes. After the ultrasonic dispersion was uniform, suspension A was obtained.

[0038] (2) A 0.3 mol / L aqueous solution of a BZY shell precursor was prepared according to a molar ratio of Ba(COOCH3)2:Zr(CH3COO)4:Y(NO3)3·6H2O:sodium dodecylbenzenesulfonate = 1.2:0.8:0.1:0.1, and the solution was stirred for 30 min using a magnetic stirrer to obtain solution B.

[0039] (3) Suspension A and solution B were mixed, and ammonia water was added to adjust the pH to 9. The solution was stirred with a magnetic stirrer for 2 h. The solution was placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min and then filtered to obtain precipitate C.

[0040] (4) The precipitate C was washed with anhydrous ethanol, and then placed in a drying oven, dried at 90 °C for 12 h, and then calcined at 950 °C for 4 h to obtain YDZ@BZY core-shell structured nanopowder.

[0041] like Figure 2 As shown in Figure 2, the lattice fringe spacing of the YDZ@BZY core-shell structured nanopowder is 0.19116nm for the outer shell and 0.17145nm for the inner core, both matching the standard pdf card. Figure 3-4 It can be seen that the elements of the powder grains are evenly distributed, and the Ba element is distributed more in the outer shell in a circular ring-shaped state, and less in the inner core. The powder particles are evenly distributed and regular and nearly spherical. The powder particle size is 80-100nm, and the average particle size is 92nm. The XRD results are as follows Figure 8 As shown, it is consistent with the expected object, but due to the low amount of Y element doping, the presence of Y element is not detected in the outer shell.

[0042] The YDZ@BZY core-shell structured nanopowder obtained in this example was sintered at 1600°C for 12 h to obtain YDZ@BZY ceramics. The AC impedance test of the YDZ@BZY ceramics was performed at 600°C in air atmosphere. The test results are shown in FIG. Figure 10 As shown, the conductivity of YDZ@BZY ceramics can reach 0.41×10 -2 S / cm.

[0043] Example 2

[0044] A Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ (δ=0.5) powder preparation method, comprising the following steps:

[0045] (1) Prepare Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O) with a concentration of 1 mol / L according to the molar ratio of Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O)=0.8:0.2:0.15. 0.786 Y 0.214 O 1.866-δ The nuclear precursor aqueous solution was then added with ammonia water to adjust the pH of the solution to 10, and the solution was stirred for 2 hours using a magnetic stirrer, and then ultrasonically dispersed for 30 minutes using an ultrasonic cleaning machine. After the ultrasonic dispersion was uniform, suspension A was obtained.

[0046] (2) A 1.5 mol / L aqueous solution of a BZY shell precursor was prepared according to a molar ratio of Ba(COOCH3)2:Zr(CH3COO)4:Y(NO3)3·6H2O:sodium dodecylbenzenesulfonate = 1.6:0.8:0.2:0.15, and the solution was stirred for 30 min using a magnetic stirrer to obtain solution B.

[0047] (3) Suspension A and solution B were mixed, and ammonia water was added to adjust the pH to 10. The solution was stirred with a magnetic stirrer for 2 h. The solution was placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min and then filtered to obtain precipitate C.

[0048] (4) The precipitate C was washed with anhydrous ethanol, and then placed in a drying oven, dried at 90 °C for 12 h, and then calcined at 950 °C for 4 h to obtain YDZ@BZY core-shell structured nanopowder.

[0049] The nanopowder prepared in this embodiment has a YDZ@BZY core-shell structure, and the elements of the powder grains are evenly distributed. The Ba element is distributed in a large amount in the outer shell and is in a circular ring-shaped state. The powder particles are evenly distributed and regular and nearly spherical.

[0050] The YDZ@BZY core-shell structured nanopowder obtained in this example was sintered at 1600°C for 12 h to obtain YDZ@BZY ceramics. The AC impedance test of the YDZ@BZY ceramics was performed at 600°C in air atmosphere. The test results are shown in FIG. Figure 11 The conductivity of YDZ@BZY ceramics can reach 0.37×10 -2 S / cm.

[0051] Comparative Example 1

[0052] The only difference between the preparation method of the YDZ@BZY core-shell structured nanopowder described in this comparative example and that in Example 1 is that the calcination temperature in this example is 900°C.

[0053] The SEM results of the YDZ@BZY core-shell structure nanopowder prepared in this comparative example are as follows: Figure 6The powder particles shown are small in size, ranging from 28 to 41 nm, with an average particle size of 36 nm, and there is obvious agglomeration in the powder.

[0054] The YDZ@BZY core-shell structured nanopowder obtained in this comparative example was sintered at 1600°C for 12 h to obtain YDZ@BZY ceramics. The AC impedance test of the YDZ@BZY ceramics was conducted at 600°C in air atmosphere. The electrical conductivity of the YDZ@BZY ceramics can reach 0.34×10 -2 S / cm.

[0055] Comparative Example 2

[0056] In this comparative example, the same method as in Example 1 was used to prepare YDZ@BZY core-shell structured nanopowders, except that the calcination temperature in this example was 850°C.

[0057] like Figure 7 As shown, the particle size of the material prepared in this comparative example is in the range of 20-32 nm, with an average particle size of 27 nm, and there is serious agglomeration.

[0058] The YDZ@BZY core-shell structured nanopowder obtained in this comparative example was sintered at 1600°C for 12 h to obtain YDZ@BZY ceramics. The AC impedance test of the YDZ@BZY ceramics was conducted at 600°C in air atmosphere. The electrical conductivity of the YDZ@BZY ceramics can reach 0.27×10 -2 S / cm.

[0059] Comparative Example 3

[0060] A Zr 0.786 Y 0.214 O 1.866-δ The preparation method of nanopowder comprises the following steps:

[0061] (1) Prepare Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O) with a concentration of 0.1 mol / L according to the molar ratio of Zr(CH3COO)4:Y(NO3)3·6H2O:citric acid (C6H8O7·H2O)=0.8:0.2:0.1. 0.786 Y 0.214 O 1.866-δ The core precursor aqueous solution was then added with ammonia water to adjust the pH of the solution to 8-10, and the solution was stirred for 2 hours using a magnetic stirrer, and then ultrasonically dispersed for 30 minutes using an ultrasonic cleaning machine. After the ultrasonic dispersion was uniform, a suspension A was obtained.

[0062] (2) Filter the suspension A to obtain precipitate C.

[0063] (3) The precipitate C was washed with anhydrous ethanol, and then placed in a drying oven, dried at 90°C for 12 hours, and then calcined at 950°C for 4 hours to obtain YDZ nanopowder.

[0064] The nanopowder obtained in this comparative example was sintered at 1600°C for 12 h to obtain YDZ ceramics. AC impedance test was performed on the YDZ ceramics at 600°C in air atmosphere. The electrical conductivity of the YDZ ceramics can reach 0.31×10 -2 S / cm.

[0065] Comparative Example 4

[0066] A BaZr 0.78 Y 0.22 O 3-δ The preparation method of nanopowder comprises the following steps:

[0067] (1) A 0.4 mol / L aqueous solution of a BZY shell precursor was prepared according to the molar ratio of Ba(COOCH3)2, Zr(CH3COO)4, Y(NO3)3·6H2O, and sodium dodecylbenzenesulfonate = 1:0.8:0.15:0.1. The solution was stirred for 30 min using a magnetic stirrer to obtain solution B.

[0068] (3) Ammonia water was added to solution B to adjust the pH to 8-10, and the solution was stirred with a magnetic stirrer for 2 h. The solution was placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min and then filtered to obtain precipitate C.

[0069] (4) The precipitate C was washed with anhydrous ethanol, and then placed in a drying oven, dried at 90°C for 12 hours, and then calcined at 950°C for 4 hours to obtain BZY nanopowder.

[0070] The nanopowder obtained in this comparative example was sintered at 1600°C for 12 h to obtain BZY ceramics. The AC impedance test of BZY ceramics was conducted at 600°C in air atmosphere. The electrical conductivity of BZY ceramics can reach 0.26×10 -2 S / cm.

[0071] Comparative Example 5

[0072] In this comparative example, the same method as in Example 1 was used to prepare YDZ@BZY core-shell structured nanopowders, except that the calcination temperature in this comparative example was 1000°C.

[0073] like Figure 5 As shown, the YDZ@BZY core-shell structure nanopowder particles obtained in this comparative example are nearly spherical, with a particle size between 112-135 nm, and the powder XRD results are as follows Figure 9As shown, it is basically consistent with the desired object.

[0074] pass Figure 4 (Example 1) and Figure 5 Comparative Example 1 shows that the average particle size of the powder increases with increasing calcination temperature. However, excessively coarse powder particle size can affect its conductivity. Therefore, the calcination temperature must be controlled within a reasonable range to ensure that the YDZ@BZY core-shell nanopowder has excellent crystallinity while avoiding excessively large particle size.

[0075] The YDZ@BZY core-shell structure nanopowder obtained in this comparative example was sintered at 1600°C for 10 hours to obtain YDZ@BZY ceramics. The AC impedance test of the YDZ@BZY ceramics was performed at 600°C in air atmosphere. The test results are as follows: Figure 12 As shown, the conductivity of YDZ@BZY ceramics can reach 0.12×10 -2 S / cm. The electrical conductivity of the YDZ@BZY ceramic in this comparative example is lower than that of the YDZ@BZY ceramic in Example 1. This is because the calcination temperature is too high, resulting in uneven composition, which in turn makes it impossible to form a pure high-conductivity two-phase interface, ultimately causing its electrical conductivity to decrease.

[0076] Comparative Example 6

[0077] A Zr 0.786 Y 0.214 O 1.866-δ / BaZr 0.78 Y 0.22 O 3-δ The preparation method of nanopowder comprises the following steps:

[0078] BaZr was obtained by ball milling barium carbonate, zirconium oxide and yttrium (Y2O3) powder in anhydrous ethanol medium for 12 h, drying and grinding, and calcining at 1300 ° C for 10 h. 0.78 Y 0.22 O 3-δ Then, BaZr 0.78 Y 0.22 O 3-δ Powder and Zr 0.786 Y 0.214 O 1.866-δ The powders were mixed, ground, dried, milled, and sieved. They were then axially pressed at 420 MPa and sintered at 1150°C for 6 h.

[0079] The YDZ / BZY nanopowder obtained in this comparative example was sintered at 1600°C for 12 hours to obtain YDZ / BZY ceramics. The AC impedance test of the YDZ / BZY ceramics was performed at 600°C in air atmosphere. The test results are shown in FIG. Figure 13As shown, the conductivity of YDZ / BZY ceramics can reach 0.23×10 -2 S / cm.

[0080] The embodiment of the present invention constructs a YDZ@BZY core-shell structured nanopowder with YDZ as the core and BZY as the shell, thereby improving the interface continuity between YDZ and BZY, increasing the ratio of the two-phase interface, and improving the conductivity of the YDZ@BZY core-shell structured nanopowder.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The conductivity of the material is improved by regulating the material structure and preparation method; Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowders of Zr 0.786 Y 0.214 O 1.866-δ For the core, BaZr 0.78 Y 0.22 O 3-δ is the shell, where δ = 0.1~0.5; The Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ The preparation method of nanopowder comprises the following steps: (1) Zr(CH3COO)4, Y(NO3)3·6H2O and citric acid were added to water to prepare a core precursor aqueous solution, and then ammonia was added to adjust the pH of the solution and stirred, and then ultrasonically dispersed to obtain suspension A; (2) Ba(COOCH3)2, Zr(CH3COO)4, Y(NO3)3·6H2O and sodium dodecylbenzenesulfonate were added to water to prepare a shell precursor aqueous solution and stirred to obtain solution B; (3) Suspension A and solution B were mixed, ammonia water was added to adjust the pH, and the mixture was stirred. The mixture was then ultrasonically dispersed and filtered to obtain precipitate C. (4) After washing, drying and calcining the precipitate C at 950 °C for 4 h, Zr 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Core-shell structured nanopowders.

2. Zr as claimed in claim 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The molar ratio of Zr(CH3COO)4, Y(NO3)3·6H2O and citric acid is 0.8:(0.1~0.2):(0.1~0.15).

3. Zr as claimed in claim 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The molar ratio of Ba(COOCH3)2, Zr(CH3COO)4, Y(NO3)3·6H2O and sodium dodecylbenzenesulfonate is (1-1.6): 0.8: (0.1-0.2): (0.1-0.15).

4. Zr as claimed in claim 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The concentration of the core precursor in the core precursor aqueous solution is 0.1-1 mol / L, and the concentration of the shell precursor in the shell precursor aqueous solution is 0.3-1.5 mol / L.

5. Zr as claimed in claim 4 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that In step (3), the volume ratio of suspension A to solution B is (0.5-1):

1.

6. Zr as claimed in claim 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The pH in step (1) is 8-10.

7. Zr as claimed in claim 1 0.786 Y 0.214 O 1.866-δ @BaZr 0.78 Y 0.22 O 3-δ Nanopowder, characterized in that The pH in step (3) is 9-10.

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