Sodium bismuth titanate powder material and preparation method thereof
By synthesizing sodium bismuth titanate nanocube powder through a two-step hydrothermal method, the problems of dispersion and crystal phase purity of sodium bismuth titanate powder in the prior art have been solved, and the preparation of high-performance ceramics with good ferroelectric properties has been realized.
Patent Information
- Application Number
- CN202511964109.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-02-27
AI Technical Summary
The sodium bismuth titanate powder prepared by existing technology has poor dispersibility, large particle size and impure crystal phase, which affects the electrical properties of ceramics.
Bismuth sodium titanate nanocube powder was synthesized by a two-step hydrothermal method. By controlling the reaction temperature and time and using sodium hydroxide as a mineralizing agent, nanocube powder with an average size of 76 nm was prepared.
The prepared nanocube powder has good dispersibility and sintering characteristics, and can be sintered at 1100℃ into ceramics with a relative density of over 95%, exhibiting excellent ferroelectric properties.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of wet chemical powder preparation technology, and in particular to a sodium bismuth titanate powder material and its preparation method. Background Technology
[0002] Ferroelectric ceramics, as an important functional ceramic material, have wide applications in machinery, electronics, aerospace, and other fields. Currently, the ferroelectric ceramics used are mainly lead-based perovskite oxides, with PbO accounting for approximately 70% of the total material content. PbO is a hazardous substance; improper handling during material preparation, use, and post-disposal can potentially harm the environment and human health. Therefore, developing high-performance, environmentally friendly lead-free ferroelectric ceramics is of great significance. Sodium bismuth titanate (Bi...) 0.5 Na 0.5 TiO3 is a class of A-site composite-substituted perovskite-structured ferroelectric materials with a relatively high Curie temperature (Tc = 320℃). Due to (Bi... 0.5 Na 0.5 TiO3 has excellent ferroelectricity and a high Curie temperature, and is considered one of the most promising candidate materials for lead-free ferroelectric ceramics.
[0003] (Bi 0.5 Na 0.5 The crystal structure, particle size, and morphology of TiO3 powder are crucial for the preparation of high-performance (Bi) powders. 0.5 Na 0.5 TiO3 ceramics have a decisive influence. (Bi) 0.5 Na 0.5 TiO3 powder is mostly prepared using traditional solid-state methods, which have the advantages of mature technology, simple process, and low cost. However, the raw materials used in solid-state synthesis methods are often not sufficiently dispersed, resulting in insufficient uniformity of chemical composition in the prepared ceramic powder, and it is difficult to obtain a single crystalline phase, thus affecting the final product (Bi). 0.5 Na 0.5 Electrical properties of TiO3 ceramics. Compared with traditional solid-state methods, wet chemical methods such as sol-gel and hydrothermal synthesis methods for synthesizing (Bi) 0.5 Na 0.5 TiO3 powder has high purity, fine particles, and good sintering properties, thus it can improve the electronic properties of BiO3. 0.5 Na 0.5 The electrical properties of TiO3 ceramics. Among these wet chemical methods, the hydrothermal method is considered one of the most effective methods for preparing high-purity, fine sodium bismuth titanate powder under mild conditions due to its low synthesis temperature, low cost, environmental friendliness, and simple process. However, the (Bi) obtained according to existing technologies... 0.5 Na 0.5TiO3 powder has poor dispersibility, and its particle morphology is mostly spherical with a size in the micrometer or submicrometer range, except for the rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 also contains a small amount of a second phase, and its synthesis time is relatively long. Therefore, it is necessary to develop new nano-scale (Bi) phases. 0.5 Na 0.5 Preparation technology of TiO3 powder. Summary of the Invention
[0004] The purpose of this invention is to provide a (Bi) 0.5 Na 0.5 This paper presents TiO3 nanocubic powder materials and their preparation methods to address the challenges posed by existing technologies for preparing (Bi) nanocubic powders. 0.5 Na 0.5 Problems such as poor dispersibility, large particle size, and impure crystal phase of TiO3 powder.
[0005] To achieve the above objectives, the present invention employs the following technical solution: A sodium bismuth titanate powder material, wherein the powder material is a rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 has a particle morphology of nanocubes with an average size of 76 nm.
[0006] In the above technical solution, the main raw materials include: bismuth nitrate pentahydrate Bi(NO3)3·5H2O, tetrabutyl titanate Ti(OC4H9)4, and sodium hydroxide NaOH as solutes, and deionized water, dilute nitric acid and anhydrous ethanol as solvents to prepare the precursor solution. At the same time, sodium hydroxide also serves as a mineralizing agent for hydrothermal reaction.
[0007] A method for preparing sodium bismuth titanate powder material specifically includes the following steps: 1) Dissolve Bi(NO3)3·5H2O pentahydrate in deionized water, then add dilute nitric acid and stir to obtain a clear and transparent solution a; 2) According to the molar ratio of Bi:Ti=1:2, dissolve tetrabutyl titanate Ti(OC4H9)4 in anhydrous ethanol, stir until clear and transparent, and then add it to solution a to obtain solution b.
[0008] 3) Dissolve sodium hydroxide (NaOH) in deionized water and stir to obtain a clear and transparent aqueous solution (c). Then add it to solution (b) and stir again to obtain a pale yellow precursor solution (d).
[0009] 4) The precursor solution d was placed in a stainless steel reactor with a polytetrafluoroethylene liner, and then the reactor was placed in a forced-air drying oven. A two-step hydrothermal method was used to synthesize (Bi). 0.5 Na0.5 TiO3 powder: First, heat the reactor to the specified temperature and keep it at that temperature for a certain period of time. Second, after the first heating is completed, cool the reactor to the specified temperature and keep it at that temperature for a certain period of time. Then, remove the reactor from the drying oven and let it cool naturally to room temperature.
[0010] 5) Wash the product after the reaction until neutral, then place it in a drying oven to dry. Grind and sieve the dried powder to obtain a pale yellow (Bi) powder. 0.5 Na 0.5 TiO3 nanocubes.
[0011] Furthermore, the two-step hydrothermal heating method specifically includes: first, heating the reactor to 180°C for 30 minutes; second, after the first heating is completed, cooling the reactor to 160°C and holding it at that temperature for 5 hours, and then removing the reactor from the drying oven and allowing it to cool naturally to room temperature.
[0012] Furthermore, in step 3), the concentration of the aqueous solution c (sodium hydroxide NaOH) is 12 mol / L.
[0013] Preferably, in step 1), 3.469g of bismuth nitrate pentahydrate is dissolved in 5ml of deionized water, and 5ml of dilute nitric acid is added. The mixture is stirred for 10 minutes to obtain a clear and transparent solution a.
[0014] Preferably, in step 2), 4.9172g of tetrabutyl titanate is dissolved in 5ml of anhydrous ethanol, stirred until clear and transparent, and then added to solution a to obtain solution b.
[0015] Compared with existing technologies, the beneficial effects of this invention are: This invention synthesizes (Bi) via a two-step hydrothermal method. 0.5 Na 0.5 TiO3 nanocube powder has advantages such as simple processing, low cost, good stability and repeatability, and mass production capability. The obtained nanocubes are rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 with an average size of 76 nm was prepared; and (Bi) 0.5 Na 0.5 TiO3 nanocubes exhibit excellent sintering properties, and can be sintered at 1100℃ for 4 hours to produce a relative density of over 95% (Bi). 0.5 Na 0.5 TiO3 ceramics. (Bi) 0.5 Na 0.5 TiO3 ceramics exhibit good ferroelectricity, with a maximum polarization, remanent polarization, and coercive field of 40.02 μC / cm.2 27.78 μC / cm 2 With a voltage of 87.5 kV / cm, it exhibits excellent ferroelectric properties compared to ceramics fired using the traditional solid-state synthesis method. Attached Figure Description
[0016] Figure 1 The images show the XRD patterns of bismuth titanate sodium powder obtained at different heating temperatures during the first heating step of the two-step hydrothermal method of the present invention, as well as the XRD patterns of bismuth titanate sodium powder synthesized by the conventional one-step hydrothermal method.
[0017] Figure 2 Scanning electron microscope images (200℃-0.5h, 160℃-5h) of bismuth titanate sodium powder prepared by the two-step heating hydrothermal method of the present invention.
[0018] Figure 3 Scanning electron microscope images (180℃-0.5h, 160℃-5h) of bismuth sodium titanate powder prepared by the two-step hydrothermal method of the present invention.
[0019] Figure 4 Scanning electron microscope images (170℃-0.5h, 160℃-5h) of bismuth titanate sodium powder prepared by the two-step heating hydrothermal method of the present invention.
[0020] Figure 5 Scanning electron microscope image of bismuth titanate sodium powder prepared by a conventional one-step hydrothermal method (180℃-6h).
[0021] Figure 6 This is a transmission electron microscope image of bismuth titanate sodium powder prepared by the two-step hydrothermal method of the present invention (180℃-0.5h, 160℃-5h).
[0022] Figure 7 The XRD patterns of bismuth titanate sodium powder prepared by the two-step heating hydrothermal method of the present invention under different holding times during the first heating process are shown.
[0023] Figure 8 The XRD patterns of bismuth titanate sodium powder prepared by the two-step hydrothermal heating method of the present invention (180℃-0.5h, 160℃-5h) at different mineralizer concentrations are shown.
[0024] Figure 9 The polarization intensity-electric field intensity hysteresis loop is the polarization intensity-electric field intensity hysteresis loop of bismuth sodium titanate ceramics prepared by firing the bismuth sodium titanate powder obtained by the present invention. Detailed Implementation
[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to specific examples of the present invention. Obviously, the described embodiments are merely illustrative and are not intended to limit the present invention.
[0026] Example 1: Step 1: Dissolve 3.469g of bismuth nitrate pentahydrate in 5ml of deionized water, add 5ml of dilute nitric acid, and stir for 10 minutes to obtain a clear and transparent solution a. Then, according to the molar ratio of Bi:Ti = 1:2, dissolve 4.9172g of tetrabutyl titanate in 5ml of anhydrous ethanol, stir until clear and transparent, and add it to solution a to obtain solution b. Then, according to the NaOH concentration of 12mol / L, dissolve 38.4g of NaOH in 40mL of deionized water, stir for 40 minutes to obtain a clear and transparent aqueous solution c. Then, add aqueous solution c to solution b, stir for 30 minutes, and obtain a pale yellow precursor solution d.
[0027] Step 2: Place the precursor solution d into three stainless steel reactors lined with polytetrafluoroethylene (PTFE). Then, place the reactors in a forced-air drying oven and conduct a hydrothermal reaction using a two-step heating method: First, heat the three reactors to 170℃, 180℃, and 200℃ respectively, and hold for 30 minutes. Second, cool the reactors to 160℃ and hold for 5 hours. After the reaction is complete, remove the reactors from the drying oven and allow them to cool naturally to room temperature.
[0028] Step 3: Wash the reaction product until neutral, then place it in an 80℃ drying oven for 8 hours. Grind and sieve the dried powder to obtain a pale yellow reactant powder.
[0029] From the above experiments, we can conclude that: In the first step, the reactor was heated to 170°C and held for 30 minutes. Under the condition that other conditions remained unchanged, the XRD diffraction peaks of the powder synthesized by the two-step hydrothermal method were low and broad, indicating that it had not yet fully crystallized into the rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 (see) Figure 1 Its particles have an average size of 180 nm and constitute an amorphous polymer (see...). Figure 2 ).
[0030] In the first step, the reactor was heated to 180°C and held for 30 minutes. Under the condition that other conditions remained unchanged, the XRD diffraction peaks of the powder synthesized by the two-step hydrothermal method were high and sharp, and the crystalline phase was rhombohedral (Bi). 0.5 Na 0.5 TiO3 (see) Figure 1 Its particle morphology is cubic, with an average size of 76 nm (see...). Figure 3), and has good dispersibility (see Figure 6 ).
[0031] In the first step, the reactor is heated to 200℃ and held for 30 minutes. Under the condition that other conditions remain unchanged, the main crystalline phase of the powder synthesized by the two-step hydrothermal method is also the rhombohedral phase (Bi). 0.5 Na 0.5 TiO3, but the XRD diffraction peaks have relatively low intensity and contain diffraction peaks of impurity phases, indicating that the crystallinity of the powder is relatively poor (see...). Figure 1 Its particle morphology is spherical, with an average size of 500 nm (see...). Figure 4 ).
[0032] Therefore, by Figure 1 and Figure 2 It can be seen that the two-step hydrothermal method is used to synthesize (Bi). 0.5 Na 0.5 By controlling the reaction temperature in the first step of TiO3 powder at 180℃, a single rhombohedral phase (Bi) can be obtained. 0.5 Na 0.5 TiO3 has a cubic morphology with an average size of 76 nm and good dispersibility.
[0033] Example 2: Step 1: Dissolve 3.469g of bismuth nitrate pentahydrate in 5ml of deionized water, add 5ml of dilute nitric acid, and stir for 10 minutes to obtain a clear and transparent solution a. Dissolve 4.9172g of tetrabutyl titanate in 5ml of anhydrous ethanol according to a Bi:Ti molar ratio of 1:2, stir until clear and transparent, and add it to solution a to obtain solution b. Dissolve 38.4g of NaOH in 40ml of deionized water according to a NaOH concentration of 12mol / L, stir for 40 minutes to obtain a clear and transparent aqueous solution c. Then add aqueous solution c to solution b, stir for 30 minutes, and obtain a pale yellow precursor solution d.
[0034] Step 2: Place the precursor solution d into three stainless steel reactors lined with polytetrafluoroethylene (PTFE). Then, place the reactors in a forced-air drying oven and conduct a hydrothermal reaction using a two-step heating method. In the first step, heat the three reactors to 180°C and hold them at that temperature for 0, 30, and 60 minutes respectively. In the second step, cool the reactors to 160°C and hold them at that temperature for 5 hours. Then, remove the reactors from the drying oven and allow them to cool naturally to room temperature.
[0035] Step 3: Wash the reaction product until neutral, then place it in an 80℃ drying oven for 8 hours. Grind and sieve the dried powder to obtain a pale yellow reactant powder.
[0036] From the above experiments, we can conclude that: The first step involves heating the reactor to 180°C and holding it at that temperature for 0 minutes, while keeping other conditions unchanged: This two-step hydrothermal synthesis method is used to synthesize the rhombohedral phase (Bi) of the powder. 0.5 Na 0.5 The diffraction peak intensity of TiO3 is relatively low, and Bi is detected. 12 TiO 20 The diffraction peaks of the rhombohedral phase indicate that it is Bi 0.5 Na 0.5 )TiO3 and Bi 12 TiO 20 Mixed phases coexist (see) Figure 7 ).
[0037] The first step involves heating the reactor to 180°C and holding it at that temperature for 30 minutes, while keeping other conditions constant: This two-step hydrothermal method is used to synthesize the rhombohedral phase (Bi) of the powder. 0.5 Na 0.5 The diffraction peaks of TiO3 were strong and sharp, and no diffraction peaks of other impurities were detected, indicating that the powder is a single-phase rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 (see) Figure 7 ).
[0038] The first step involves heating the reactor to 180°C and holding it at that temperature for 60 minutes, while keeping other conditions constant: This two-step hydrothermal method is used to synthesize the rhombohedral phase (Bi) of the powder. 0.5 Na 0.5 TiO3 has relatively strong diffraction peak intensities, but Bi... 12 TiO 20 The strong diffraction peaks of the impurity phase indicate that the powder is a rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 and impurity phase Bi 12 TiO 20 Both coexist (see) Figure 7 ).
[0039] Therefore, by Figure 7 It can be seen that the two-step hydrothermal method is used to synthesize (Bi). 0.5 Na 0.5 TiO3 powder, under the condition of a first-step reaction temperature of 180℃ and a reaction time controlled at 30 minutes, can yield a single rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 powder has the best crystal quality.
[0040] Example 3: Step 1: Dissolve 3.469g of bismuth nitrate pentahydrate in 5ml of deionized water, add 5ml of dilute nitric acid, and stir for 10 minutes to obtain a clear and transparent solution a. Dissolve 4.9172g of tetrabutyl titanate in 5ml of anhydrous ethanol according to the molar ratio of Bi:Ti = 1:2, stir until clear and transparent, and add it to solution a to obtain solution b. Weigh NaOH according to the proportions of NaOH concentrations of 6, 9, 12, and 14 mol / L, respectively, and dissolve it in 40ml of deionized water. Stir for 40 minutes to obtain clear and transparent NaOH aqueous solutions c of four concentrations. Then add aqueous solution c to solution b and stir for 30 minutes to obtain four pale yellow precursor solutions d.
[0041] Step 2: Place the four precursor solutions d into stainless steel reactors lined with polytetrafluoroethylene (PTFE). Then, place the reactors in a forced-air drying oven and conduct a hydrothermal reaction using a two-step heating method. First, heat the reactors to 180°C and hold for 30 minutes. Second, cool the reactors to 160°C and hold for 5 hours. Then, remove the reactors from the drying oven and allow them to cool naturally to room temperature.
[0042] Step 3: Wash the product after the reaction until it is neutral, then place it in an 80℃ drying oven to dry for 8 hours. Then grind and sieve the dried powder to obtain a light yellow powder.
[0043] From the above experiments, we can conclude that: The powder synthesized from the precursor solution prepared with a NaOH concentration of 6 mol / L exhibited low and broad XRD diffraction peaks, indicating that the rhombohedral phase (Bi) formed in the reaction... 0.5 Na 0.5 TiO3 powder is relatively scarce (see) Figure 8 ).
[0044] The powder synthesized using a precursor solution prepared with 9 mol / L NaOH has a rhombohedral phase (Bi). 0.5 Na 0.5 The intensity of the XRD diffraction peaks of TiO3 increased, but remained low, indicating that the rhombohedral phase (Bi) had not yet fully formed. 0.5 Na 0.5 TiO3 powder (see) Figure 8 ).
[0045] The powder prepared according to the precursor solution with a NaOH concentration of 12 mol / L has a rhombohedral phase (Bi). 0.5 Na 0.5 The XRD diffraction peaks of TiO3 were sharp and showed a dramatic increase in intensity. Furthermore, no other impurity phase diffraction peaks were detected, indicating that the reaction products had all crystallized into the rhombohedral phase (Bi). 0.5 Na0.5 TiO3 (see) Figure 8 ).
[0046] The powder prepared according to the precursor solution with a NaOH concentration of 14 mol / L has a rhombohedral phase (Bi). 0.5 Na 0.5 The XRD diffraction peaks of TiO3 are sharp and have high intensity, but the impurity phase Bi is present. 12 TiO 20 The diffraction peaks indicate that the reaction product is (Bi). 0.5 Na 0.5 TiO3 and Bi 12 TiO 20 Both coexist (see) Figure 8 ).
[0047] Therefore, by Figure 8 It can be seen that the two-step hydrothermal method is used to synthesize (Bi). 0.5 Na 0.5 TiO3 powder, when prepared into a precursor solution with a NaOH concentration of 12 mol / L, yields a (Bi) phase consisting entirely of rhombohedral phase. 0.5 Na 0.5 TiO3 powder, and the crystal quality is the best.
[0048] Example 4: Control group: Prepared using a conventional one-step hydrothermal method (Bi 0.5 Na 0.5 )TiO3 powder.
[0049] Step 1: Dissolve 3.469g of bismuth nitrate pentahydrate in 5ml of deionized water, add 5ml of dilute nitric acid, and stir for 10 minutes to obtain a clear and transparent solution a. Dissolve 4.9172g of tetrabutyl titanate in 5ml of anhydrous ethanol according to a Bi:Ti molar ratio of 1:2, stir until clear and transparent, and add it to solution a to obtain solution b. Dissolve 38.4g of NaOH in 40ml of deionized water according to a NaOH concentration of 12mol / L, stir for 40 minutes to obtain a clear and transparent aqueous solution c. Then add aqueous solution c to solution b, stir for 30 minutes, and obtain a pale yellow precursor solution d.
[0050] Step 2: The precursor solution d is placed in a stainless steel reactor with a polytetrafluoroethylene liner, and then the reactor is placed in a forced-air drying oven. A conventional one-step hydrothermal reaction is performed, compared with the two-step hydrothermal synthesis of (Bi). 0.5 Na 0.5To compare the reaction temperature and reaction time (180℃-0.5h, 160℃-5h) of TiO3 powder, the reactor was heated to 180℃ in a drying oven and kept at that temperature for 6 hours. Then, the reactor was removed from the drying oven and allowed to cool naturally to room temperature.
[0051] Step 3: Wash the product after the reaction until it is neutral, then place it in an 80℃ drying oven to dry for 8 hours. Then grind and sieve the dried powder to obtain a light yellow product powder.
[0052] The experimental results above show that: The powder synthesized using a conventional one-step hydrothermal method, holding at 180℃ for 6 hours, has a rhombohedral phase (Bi). 0.5 Na 0.5 The diffraction peaks of TiO3 were relatively weak, and the impurity phase Bi was also detected. 12 TiO 20 The diffraction peaks (see) Figure 1 The particles were spherical with an average size of 520 nm. Additionally, needle-like and flocculent Bi particles were observed. 12 TiO 20 Miscellaneous phases (see) Figure 5 ).
[0053] A comparison of Examples 1, 2, 3, and 4 reveals that, compared to the conventional one-step hydrothermal method of Example 4, the powder synthesized by the two-step hydrothermal method of this invention has a rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 (see) Figure 1 Its particle morphology is cubic, with an average size of approximately 76 nm (see...). Figure 3 and Figure 6 ), and has good dispersibility (see Figure 6 The (Bi) prepared using this invention 0.5 Na 0.5 Bismuth titanate sodium ceramics, prepared by sintering TiO3 nanocube powder at 1100℃ for 4 hours, exhibit good ferroelectric properties (see...). Figure 9 Its relative density is over 95%, and its maximum polarization, remanent polarization, and coercive field are 40.02 μC / cm². 2 27.78 μC / cm 2 The result of 87.5 kV / cm proves that the (Bi) prepared in this invention... 0.5 Na 0.5 TiO3 nanocube powder has broad application prospects in fields such as bismuth titanate sodium ceramics, bismuth titanate sodium-based ceramics, and thermistor ceramics.
[0054] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A sodium bismuth titanate powder material, characterized in that, The powder material is a rhombohedral phase (Bi). 0.5 Na 0.5 TiO3 has a particle morphology of nanocubes with an average size of 76 nm.
2. A method for preparing sodium bismuth titanate powder material as described in claim 1, characterized in that, Specifically, the methods and steps include the following: 1) Dissolve Bi(NO3)3·5H2O pentahydrate in deionized water, then add dilute nitric acid and stir to obtain a clear and transparent solution a; 2) According to the molar ratio of Bi:Ti=1:2, dissolve tetrabutyl titanate Ti(OC4H9)4 in anhydrous ethanol, stir until clear and transparent, and then add it to solution a to obtain solution b; 3) Dissolve sodium hydroxide (NaOH) in deionized water and stir to obtain a clear and transparent aqueous solution (c). Then add it to solution (b) and stir again to obtain a pale yellow precursor solution (d). 4) The precursor solution d was placed in a stainless steel reactor with a polytetrafluoroethylene liner, and then the reactor was placed in a forced-air drying oven. A two-step hydrothermal method was used to synthesize (Bi). 0.5 Na 0.5 )TiO3 powder; 5) Wash the product after the reaction until neutral, then place it in a drying oven to dry. Grind and sieve the dried powder to obtain (Bi). 0.5 Na 0.5 TiO3 nanocubes.
3. The method for preparing nano-cubic bismuth sodium titanate according to claim 2, characterized in that, The two-step hydrothermal heating method specifically includes: first, heating the reactor to 180°C for 30 minutes; second, after the first heating is completed, cooling the reactor to 160°C and holding it at that temperature for 5 hours, then removing the reactor from the drying oven and allowing it to cool naturally to room temperature.
4. The method for preparing nano-cubic bismuth sodium titanate according to claim 2, characterized in that, The concentration of the aqueous solution c is 12 mol / L.
5. The method for preparing nano-cubic bismuth sodium titanate according to claim 2, characterized in that, In step 1), 3.469g of bismuth nitrate pentahydrate is dissolved in 5ml of deionized water, and 5ml of dilute nitric acid is added. The mixture is stirred for 10 minutes to obtain a clear and transparent solution a.
6. The method for preparing nano-cubic bismuth sodium titanate according to claim 2, characterized in that, In step 2), 4.9172g of tetrabutyl titanate is dissolved in 5ml of anhydrous ethanol and stirred until clear and transparent. Then, it is added to solution a to obtain solution b.