Preparation method and application of nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material

Abstract

The application provides a preparation method and application of a nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material. The preparation method is simple in operation and does not need complex reactions and reagents in multiple steps. The chiral nano-flower composite material synthesized by a solvothermal method has a strong and symmetrical circular dichroism (CD) signal, is obvious in flower shape, large in specific surface area, has excellent circularly polarized light selective absorption capacity, and can be better applied to the field of asymmetric photocatalysis, such as degradation of organic pollutants under circularly polarized light, and shows obvious enantioselectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials science, and more particularly to a preparation method and application of nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material. BACKGROUND

[0002] Due to the importance of chirality in biochemical processes in nature and the development of new technologies, mastering the operation of chirality at the nanoscale has always been the task of chemists, physicists and materials scientists. At the nanoscale, so far the most common example of inorganic chirality is single-component nanocrystals. Compared with these reported chiral nanomaterials, the chiral composite structure that integrates chirality in multifunctional materials is a new topic in nanoscience, which is attractive in the fields of chiral sensing, asymmetric catalysis and spin-based optics. However, the controlled synthesis of chiral composite nanostructures is still a major challenge. Most available chiral multi-component systems are limited to chiral configurations based on soft intersters, resulting in weak interactions between adjacent components and limiting material combinations. It is very meaningful to design chiral composite materials with strong chiral coupling between materials and chiral-sensitive chemical properties.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application aims to provide a preparation method and application of nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material.

[0005] The present application adopts the following technical scheme: a preparation method of nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material, comprising the following steps:

[0006] (1) Chiral glucose, titanium source and barium source are added to a 4 mol / L alkali solution and stirred uniformly; the molar ratio of the barium source, the titanium source and the chiral glucose is 0.5-1:0.5-1:3.5-∞, wherein the barium source and the titanium source are calculated based on Ba and Ti elements.

[0007] (2) The mixed solution obtained after step (1) is heated to 100-140℃ in a reaction kettle and reacted for 12-48 h; after the reaction is completed, solid-liquid separation is performed, and the nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material is obtained.

[0008] Further, the chiral glucose is D-glucose or L-glucose.

[0009] Further, the barium source is at least one of barium chloride or barium hydroxide octahydrate. Preferably, the barium source is barium hydroxide octahydrate.

[0010] Further, the titanium source is n-butyl titanate.

[0011] Further, the alkali solution is sodium hydroxide.

[0012] Further, the molar ratio of the barium source, the titanium source and the chiral glucose is 1:0.6:5.5, wherein the barium source and the titanium source are calculated according to Ba and Ti elements.

[0013] Further, in the step (2), the reaction time is 24 h.

[0014] Further, the method of the solid-liquid separation is: deionized water washing and centrifugation for 3 times, and drying at 60 ℃ for 12 h.

[0015] The nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material synthesized by the preparation method has the application in asymmetric photocatalysis.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] 1. The nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material has excellent asymmetric photocatalytic performance.

[0018] 2. The nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material synthesized by the solvothermal method does not need complex reaction process and reagent, has large specific surface area, rich active sites and high stability. DETAILED DESCRIPTION

[0019] Figure 1 The XRD pattern of the chiral photocatalytic material prepared for the examples and comparative examples.

[0020] Figure 2 The CD pattern of the chiral photocatalytic material prepared for the examples.

[0021] Figure 3 The SEM image of the chiral photocatalytic material prepared for the examples and comparative examples.

[0022] Figure 4 The asymmetric photocatalytic performance diagram of the chiral photocatalytic material prepared for the examples and comparative examples.

[0023] Figure 5 The circular dichroism spectrum of the products with different chiral glucose dosages.

[0024] Figure 6 The circular dichroism spectrum of the products with different reaction times.

[0025] Figure 7 The circular dichroism spectrum of the products with different reaction temperatures.

[0026] Figure 8 Circular dichroism spectra of the products for different molar ratios of barium source to titanium source. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described in conjunction with the following examples. The following examples are intended to illustrate the present application and are not intended to limit the scope of the present application.

[0028] The methods are all conventional unless otherwise specified. The materials are all commercially available unless otherwise specified.

[0029] The performance evaluation methods of D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 are as follows:

[0030] The phase evaluation methods of D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 are as follows:

[0031] X-ray diffraction (XRD): The crystal structure of the prepared D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 materials was analyzed by a D8 Advance series wide-angle X-ray diffractometer of Bruker Company in Germany, the scanning speed was 5° / min, and the scanning range was 10°-80°.

[0032] The micro-morphology evaluation methods of D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 are as follows:

[0033] Scanning electron microscope (SEM): The prepared D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 materials were tested on a JSM-IT300 series scanning electron microscope of JEOL Company in Japan, and the acceleration voltage was 5-20 kV.

[0034] The asymmetric photocatalytic performance evaluation methods of BaTiO3, D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 are as follows:

[0035] Taking the asymmetric photocatalytic degradation of methylene blue by D-BaTiO3 / BaCO3 as an example, the specific process is as follows: first, 15 ml of 5 mg / L methylene blue solution was added to a 25 mL quartz beaker, and then 10 mg of D-BaTiO3 / BaCO3 material was added. The reaction system was stirred in the dark for 15 min for adsorption-desorption equilibrium, and then under the irradiation of R / LCP light source, samples were taken every 60 min for a total of 8 times (i.e. 8 h of reaction), and after centrifugation, the absorbance was measured with 1000 μL microcuvette to observe the asymmetric light degradation.

[0036] Preparation of nanoflower-like chiral BaTiO3 / BaCO3

[0037] Firstly, 0.6309 g Ba(OH)2·8H2O (0.002 mol), 0.4084 g C 16 H 36 O4Ti (0.0012 mol), 2 g D-glucose (0.011 mol) were dispersed in 30 mL deionized water at room temperature, then 4.800 g NaOH was added and stirred magnetically for 1 h, finally the obtained suspension was transferred into a stainless steel autoclave lined with polytetrafluoroethylene, and reacted at 140 ℃ for 24 h. After the reaction, the product was washed with deionized water and centrifuged for 3 times, and then dried at 60 ℃ for 12 h to obtain chiral D-BaTiO3 / BaCO3 material.

[0038] Preparation of nanoflower-like chiral BaTiO3 / BaCO3

[0039] Firstly, 0.6309 g Ba(OH)2·8H2O (0.002 mol), 0.4084 g C 16 H 36 O4Ti (0.0012 mol), 2 g L-glucose (0.011 mol) were dispersed in 30 mL deionized water at room temperature, then 4.800 g NaOH was added and stirred magnetically for 1 h, finally the obtained suspension was transferred into a stainless steel autoclave lined with polytetrafluoroethylene, and reacted at 140 ℃ for 24 h. After the reaction, the product was washed with deionized water and centrifuged for 3 times, and then dried at 60 ℃ for 12 h to obtain chiral L-BaTiO3 / BaCO3 material.

[0040] Preparation of BaTiO3

[0041] Firstly, 0.6309 g Ba(OH)2·8H2O (0.002 mol), 0.4084 g C 16 H 36 O4Ti (0.0012 mol) were dispersed in 30 mL deionized water at room temperature, then 4.800 g NaOH was added and stirred magnetically for 1 h, finally the obtained suspension was transferred into a stainless steel autoclave lined with polytetrafluoroethylene, and reacted at 140 ℃ for 24 h. After the reaction, the product was washed with deionized water and centrifuged for 3 times, and then dried at 60 ℃ for 12 h to obtain BaTiO3 material.

[0042] Based on XRD test characterization, the results are as follows Figure 1As shown, both Example 1 and Example 2 correspond to the standard card PDF #35-0795 of BaTiO3 and the standard card PDF #05-0378 of BaCO3, indicating that both BaTiO3 and BaCO3 phases exist in the material.

[0043] Based on circular dichroism (CD) test characterization, the results are as shown in Figure 2 As shown, Example 1 and Example 2 are composite materials prepared under different configurations of glucose induction, and D-BaTiO3 / BaCO3 and L-BaTiO3 / BaCO3 show very strong mirror symmetry in the ultraviolet region, proving that the chiral composite material is successfully constructed.

[0044] Based on SEM test characterization, the results are as shown in Figure 3 As shown, it can be found that Comparative Example 1 is irregular small block; Example 1 and Example 2 are both nanoflower spherical, exposing a large specific surface area, which will adsorb more pollutant molecules in the catalytic process, and at the same time expose more active sites, which is conducive to the redox reaction.

[0045] Under the light of a 2 W AC 90-240 V 275 nm deep ultraviolet lamp source, after passing through an L / RCP polarizer, the methylene blue solution was degraded in a controllable cooling water circulator at 20°C for 8 h, and the asymmetric photocatalytic activity of the L- / D-BaTiO3 / BaCO3 nanoflower was evaluated. The photodegradation solution was mixed by 15 mL of MB aqueous solution (5 mg / L) and 10 mg of catalyst. Stirring in the dark for 15 min to ensure good mixing and reaching adsorption-desorption equilibrium before irradiation. Under CPL irradiation, take a sample every 1 h, each time take 800 µL, after centrifugation, use 1000 µL microcuvette for absorbance measurement.

[0046] Through the asymmetric photocatalytic degradation of pollutants performance test of the sample, the results are as shown in Figure 4 As shown, the degradation rate of BaTiO3 under left-handed light is 25.13%, and the degradation rate under right-handed light is 24.98%; while the degradation rate of D-BaTiO3 / BaCO3 under left-handed light is 18.58%, and the degradation rate under right-handed light is 30.03%; the degradation rate of L-BaTiO3 / BaCO3 under left-handed light is 27.52%, and the degradation rate under right-handed light is 17.98%.

[0047] The specific data are listed in Table 1.

[0048] Table 1 Degradation rate table of methylene blue under asymmetric light catalytic degradation

[0049]

[0050] As can be seen from the data in Table 1, compared with Comparative Example 1, both Example 1 and Example 2 show obvious differences in enantioselectivity, and the degradation performance of D-BaTiO3 / BaCO3 under right-handed light is better than that under left-handed light, while the degradation performance of L-BaTiO3 / BaCO3 is opposite.

[0051] On the basis of Example 1, the amount of D-glucose is changed to 1.0 g, 1.2 g, 1.4 g, 1.6 g, 2.0 g and 3.0 g respectively, and the circular dichroism spectra of the product D-BaTiO3 / BaCO3 material are as shown in Figure 5 When the addition amount of glucose reaches 1.4 g, the CD signal is induced.

[0052] On the basis of Example 1, the reaction time is changed to 12 h, 24 h and 48 h respectively, and the circular dichroism spectra of the product D-BaTiO3 / BaCO3 material are as shown in Figure 6 It is shown that strong chiral signals can be generated in 12 h-48 h.

[0053] On the basis of Example 1, the reaction temperature is changed to 100℃, 140℃ and 160℃ respectively, and the circular dichroism spectra of the product D-BaTiO3 / BaCO3 material are as shown in Figure 7 It is shown that the lower the temperature, the lower the crystallinity of the material, but when the temperature reaches 160℃, the chiral signal cannot be induced.

[0054] In the case of 2 g of glucose addition amount, different molar ratios of barium source and titanium source are used to control the peak position and intensity of the CD signal Figure 8 , which is only for reference.

[0055] Finally, the method of the present application is only a preferred embodiment, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing nanoflower-shaped chiral BaTiO3 / BaCO3 photocatalytic material, characterized in that, The method comprises the following steps: (1) adding chiral glucose, a titanium source and a barium source into a 4 mol / L alkali solution and stirring until uniform; the molar ratio of the barium source, the titanium source and the chiral glucose is 1:0.6:5.5, wherein the barium source and the titanium source are calculated according to Ba and Ti elements; (2) heating the mixed solution obtained after the treatment in step (1) to 100-140 ℃ in a reaction kettle and reacting for 12-48 h; after the reaction is completed, solid-liquid separation is performed, thereby obtaining the nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material.

2. The production method according to claim 1, characterized by, The chiral glucose is D-glucose or L-glucose.

3. The preparation method according to claim 1, characterized in that, The barium source is at least one of barium chloride or barium hydroxide octahydrate.

4. The production method according to claim 3, characterized by, The barium source is barium hydroxide octahydrate.

5. The preparation method according to claim 1, characterized in that, The titanium source is n-butyl titanate.

6. The method of claim 1, wherein, The alkali solution is sodium hydroxide.

7. The preparation method according to claim 1, characterized in that, In step (2), the reaction time is 24 h.

8. The method of claim 1, wherein, The method for solid-liquid separation is: washing with deionized water and centrifuging 3 times, and drying at 60 ℃ for 12 h.

9. Application of the nano-flower-shaped chiral BaTiO3 / BaCO3 photocatalytic material synthesized by the preparation method of any one of claims 1-7 in asymmetric photocatalysis.

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