A symbiotic bismuth-based layered ferroelectric material Bi 5 TiNbWO 15 Preparation method and product and application thereof

Abstract

The invention discloses a symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 Preparation method, products and applications thereof. In the preparation method, the raw materials Bi2O3, TiO2, Nb2O5 and WO3 are first weighed according to the stoichiometric ratio and put into a ball mill for 12-24 hours; then the dried powder is pre-calcined at 800-900°C for 6-10 hours, and then secondary calcined at 900-1150°C for 2-6 hours; finally, calcined at 600-700°C for 30-60 minutes to remove the stress generated by ball milling. The method is simple to operate and low in cost. The obtained symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 It has excellent piezoelectric catalytic performance and can be well applied in the field of piezoelectric catalysis, including piezoelectric catalytic degradation of various pollutants in water, reduction of CO2 to carbon-containing fuels, and cracking of water to obtain hydrogen and oxygen.

Description

Technical Field

[0001] The present invention relates to a layered bismuth-based semiconductor material, and in particular to a preparation method of the layered bismuth-based material, a product thereof and an application thereof. Background Art

[0002] It is urgent to develop green, clean, new and efficient environmental protection technologies to solve environmental problems. Piezoelectric catalysis, as an emerging catalytic technology, can induce piezoelectric materials to generate piezoelectric potential by collecting mechanical energy such as friction, vibration, waves, natural wind and environmental noise, and then drive the realization of redox reactions, which shows great potential in water pollution treatment. However, piezoelectric catalysis research is still in its infancy, and the low mechanical energy conversion efficiency is far from meeting the needs of industrial applications. Therefore, it is of great scientific significance to develop new piezoelectric catalytic materials and optimize and improve the performance of piezoelectric catalysis.

[0003] The crystal structure of layered bismuth-based materials is composed of a unique (Bi2O2) 2+ The nanostructured carbon nanotubes are composed of layers and interlayer anions or anionic groups, and show excellent performance in ferroelectrics, dielectrics, photocatalysis and other fields. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO is proposed. 15 A preparation method, and a product obtained by the method and its application.

[0005] Technical solution: A symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 A preparation method comprising:

[0006] First, the raw materials Bi2O3, TiO2, Nb2O5, and WO3 are weighed according to the stoichiometric ratio, placed in a ball mill and ball milled for 12-24 hours, and the ball milling medium is anhydrous ethanol; then, the dried powder is pre-calcined at 800-900°C for 6-10 hours, and after cooling, it is secondary calcined at 900-1150°C for 2-6 hours; finally, it is calcined at 600-700°C for 30-60 min to remove the stress generated by ball milling.

[0007] Furthermore, the ball milling time is 18 h; the pre-calcination temperature is 850 ° C, and the calcination time is 7 h; the secondary calcination temperature is 1000 ° C, and the calcination time is 4 h; the stress removal calcination temperature is 650 ° C, and the calcination time is 45 min.

[0008] Symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO prepared according to the method 15 .

[0009] According to the symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 Application, the Bi5TiNbWO 15 Application in piezoelectric catalysis.

[0010] Furthermore, the piezoelectric catalysis includes piezoelectric catalysis to degrade pollutants in water, reduce CO2 to carbon-containing fuels, and crack water to obtain hydrogen and oxygen.

[0011] Beneficial effects: 1. The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO of the present invention 15 Preparation method, through special control of ball milling and calcination, the prepared symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 The invention has excellent piezoelectric catalytic performance, and the preparation method has the advantages of simple operation, low cost and high stability.

[0012] 2. Symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO prepared by the present invention 15 It has excellent piezoelectric catalytic performance and high activity in the piezoelectric catalytic degradation process. This is the first time that its application in the field of piezoelectric catalytic degradation has been disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO of the present invention 15 Preparation method flow chart;

[0014] Figure 2 Bi5TiNbWO in Example 1 15 , XRD patterns of Bi2WO6 and Bi3TiNbO9;

[0015] Figure 3 Bi5TiNbWO in Example 1 15 , SEM images of Bi2WO6 and Bi3TiNbO9;

[0016] Figure 4 Bi5TiNbWO in Example 1 15 , Bi2WO6, and Bi3TiNbO9 piezoelectric degradation performance line graph. DETAILED DESCRIPTION

[0017] The specific embodiments of the present invention are further described in detail below in conjunction with the examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. The methods described are conventional methods unless otherwise specified. The materials described can be obtained from public commercial channels unless otherwise specified.

[0018] Firstly, the symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO obtained in the following example is introduced. 15 Performance evaluation method of comparative materials Bi2WO6 and Bi3TiNbO9:

[0019] 1. Bi5TiNbWO 15 , Bi2WO6, Bi3TiNbO9 phase evaluation method:

[0020] X-ray diffraction (XRD): The above materials were analyzed for their crystal structures by D8 Advance series wide-angle X-ray diffractometer of Bruker Company of Germany, with a scanning speed of 5° / min and a scanning range of 10°-70°.

[0021] 2. Bi5TiNbWO 15 , Bi2WO6, Bi3TiNbO9 micromorphology evaluation method:

[0022] Scanning electron microscope (SEM): The above materials were tested on a JSM-IT300 series scanning electron microscope of JEOL, Japan, with an acceleration voltage of 5-20 KV.

[0023] 3. Bi2WO6, Bi3TiNbO9, Bi5TiNbWO 15 Evaluation method of RhB piezoelectric degradation performance:

[0024] Bi5TiNbWO 15 Taking the degradation of Rhodamine B as an example, the specific process is as follows: 50 mg of the intergrown bismuth-based layered ferroelectric material Bi5TiNbWO 15 Place in a three-necked beaker containing 100 ml of Rhodamine B solution (100 mg / L), place the reaction system in a KQ-400DE CNC ultrasonic cleaner with a stirring speed of 220-260 r / s and then stir in the dark for 30 min to allow the mixture to reach adsorption-desorption equilibrium at room temperature. After 240 W, 40 kHz ultrasonic vibration, collect samples every 15 min, and take 4 samples in total (i.e., react for 1 h). The absorbance of Rhodamine B is measured by UV-1200 liquid ultraviolet spectrophotometer.

[0025] The degradation process of Rhodamine B by Bi2WO6 and Bi3TiNbO9 is consistent with the above. Example

[0026] like Figure 1 As shown, a symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15Preparation method: First, the raw materials Bi2O3, TiO2, Nb2O5, and WO3 were weighed according to the stoichiometric ratio, mixed with anhydrous alcohol in a nylon jar and ball-milled for 18 hours. Then, the dried powder was pre-calcined at 850℃ for 7 hours, and then calcined at 1000℃ for 4 hours after cooling. Finally, the refined powders were calcined at 650℃ for 60 minutes to remove the stress generated by ball milling, and finally the material sample was obtained.

[0027] The piezoelectric catalytic performance of the prepared samples was evaluated by degrading the pollutant Rhodamine B under ultrasonic vibration at 40 kHz and 260 W. 50 mg of sample powder was dispersed in 100 mL of (RhB) pollutant aqueous solution with a concentration of 100 mg / L. Before the degradation experiment, samples were taken to determine the adsorption capacity of the piezoelectric catalyst for pollutants. Stirring was carried out for 30 minutes under the condition of ultrasound off, and samples were taken every 15 minutes to allow the catalyst to reach adsorption equilibrium. Subsequently, ultrasonic vibration was started, and samples were taken every 15 minutes, for a total of 4 times, and the reaction was carried out for 1 hour. The temperature was maintained at 25±5 ℃ during the reaction. The resulting solution was centrifuged and the absorbance of Rhodamine B was determined by UV-1200 liquid ultraviolet spectrophotometer.

[0028] The present invention discloses a bismuth-based layered ferroelectric material Bi5TiNbWO 15 Piezoelectric catalysis principle: Symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 Its crystal structure is non-centrosymmetric, and it can convert mechanical energy into chemical energy when subjected to external stress. Under the action of ultrasonic vibration, the pressure generated by the quenching of cavitation bubbles makes Bi5TiNbWO 15 Deformation occurs, generating a strong internal polarization electric field. The carriers inside the material migrate to different polar surfaces and combine with oxygen or water molecules to form a variety of active oxygen species that participate in the degradation reaction. At the same time, the energy band tilts, making electrons and holes have stronger redox ability, thereby having a higher catalytic efficiency.

[0029] In this example, the preparation method of the comparative material Bi2WO6 is as follows: the raw materials Bi2O3, TiO2, and WO are weighed according to the stoichiometric ratio, mixed with anhydrous alcohol in a nylon jar and ball-milled for 1 hour. Then, the dried powder is calcined at 850°C for 7 hours; finally, the refined powder is heated at 600°C for 60 minutes to remove the stress generated by ball milling, thereby obtaining the Bi2WO6 material.

[0030] Preparation method of comparative material Bi3TiNbO9: The raw materials Bi2O3, TiO2, and Nb2O5 were weighed according to the stoichiometric ratio, mixed with alcohol in a nylon jar and ball-milled for 24 h. Then, the dried powder was calcined at 1000 °C for 4 h. Finally, the refined powder was heated at 600 °C for 60 min to remove the stress generated by ball milling, and Bi3TiNbO9 solid powder was obtained.

[0031] The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO prepared in this example 15 The Bi2WO6 and Bi3TiNbO9 prepared by the above process were evaluated by X-ray diffraction (XRD) for phase and micromorphology, and the following results were obtained: Figure 2 and Figure 3 Results shown.

[0032] for Figure 1 By performing XRD test on the sample, the Bi5TiNbWO prepared in the embodiment of the present invention 15 The prepared Bi2WO6 and Bi3TiNbO9 correspond to their standard cards PDF﹟(31-0203), PDF﹟(39-0256), and PDF﹟39-0233), respectively, indicating that the synthesized samples are pure phase without other impurities.

[0033] for Figure 2 By performing SEM tests on the samples, it can be found that the sample thickness of the three materials prepared in this embodiment ranges from about 10 to 15 μm.

[0034] like Figure 4 As shown in the figure, it can be seen from the data in the figure that compared with the two samples of Bi2WO6 and Bi3TiNbO9, the symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO prepared in this embodiment 15 It has excellent piezoelectric response performance and good piezoelectric catalytic activity. Example

[0035] A symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 Preparation method: First, the raw materials Bi2O3, TiO2, Nb2O5, and WO3 were weighed according to the stoichiometric ratio, mixed with anhydrous alcohol in a nylon jar and ball-milled for 12 hours. Then, the dried powder was pre-calcined at 800℃ for 6 hours, and then calcined at 900℃ for 2 hours after cooling. Finally, the refined powders were calcined at 600℃ for 30 minutes to remove the stress generated by ball milling, and finally the material sample was obtained, which can be used to reduce CO2 to carbon-containing fuel. Example

[0036] A symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 Preparation method: First, the raw materials Bi2O3, TiO2, Nb2O5, and WO3 are weighed according to the stoichiometric ratio, mixed with anhydrous alcohol in a nylon jar and ball-milled for 24 hours. Then, the dried powder is pre-calcined at 900℃ for 10 hours, and after cooling, it is secondary calcined at 1150℃ for 6 hours. Finally, the refined powders are calcined at 700℃ for 60 minutes to remove the stress generated by ball milling, and finally the material sample is obtained, which can be used to crack water to obtain hydrogen and oxygen.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO 15 The preparation method is characterized in that include: First, the raw materials Bi2O3, TiO2, Nb2O5, and WO3 are weighed according to the stoichiometric ratio, placed in a ball mill and ball milled for 12-24 hours, and the ball milling medium is anhydrous ethanol; then, the dried powder is pre-calcined at 800-900℃ for 6-10 hours, and after cooling, it is secondary calcined at 900-1150℃ for 2-6 hours; finally, it is calcined at 600-700℃ for 30-60 min to remove the stress generated by ball milling.

2. The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO according to claim 1 15 The preparation method is characterized in that The ball milling time is 18h; the pre-calcination temperature is 850℃, and the calcination time is 7h; the secondary calcination temperature is 1000℃, and the calcination time is 4h; the stress removal calcination temperature is 650℃, and the calcination time is 45 min.

3. The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO prepared by the method according to claim 1 or 2 15 .

4. The symbiotic bismuth-based layered ferroelectric material Bi5TiNbWO according to claim 3 15 The application is characterized in that The Bi5TiNbWO 15 Applied to piezoelectric catalysis; the piezoelectric catalysis includes piezoelectric catalysis to degrade pollutants in water, reduce CO2 to carbon-containing fuel, and crack water to obtain hydrogen and oxygen.

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