Method for preparing Bi2O2CO3 nanosheet through self-template out-phase interface in-situ oxidation-reduction reaction

Abstract

The invention provides a method for preparing Bi2O2CO3 nanosheets through a self-template out-phase interface in-situ oxidation-reduction reaction, which comprises the following steps: adding NaBiO3. 2H2O and C3N3 (NH2) 3 into a hydrothermal reaction kettle containing distilled water, and uniformly stirring to obtain a solid-liquid mixture; the solid-liquid mixture is subjected to in-situ oxidation-reduction reaction through a heterogeneous interface of a self-template under the hydrothermal condition, and the Bi2O2CO3 nanosheet is prepared; wherein NaBiO3. 2H2O is used as a bismuth source, and is also used as an oxidizing agent and a solid template agent at the same time. A self-template out-phase interface in-situ oxidation-reduction reaction preparation technology is adopted, agglomeration of product particles can be reduced, and the preparation process is simple and easy to control; meanwhile, NaBiO3. 2H2O is not only a bismuth source, but also an oxidizing agent and a solid template agent, so that the method does not need to add an additional redox agent or template agent, the product purity is improved, and the green synthesis requirements of materials are met.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials and their preparation, and in particular to a method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-template heterogeneous interface. Background Art

[0002] Bismuth oxycarbonate (Bi2O2CO3), also known as bismuth subcarbonate, has important applications in medicine, environmental protection, materials and other fields due to its unique layered structure, chemical stability and versatility.

[0003] Currently, bismuth oxycarbonate has been widely used in the pharmaceutical industry as an astringent, X-ray diagnostic sunscreen, and for the treatment of gastritis, bacterial dysentery, diarrhea, enteritis, etc. In addition, bismuth oxycarbonate can be used to manufacture bismuth salts, enamel solvents, and pearlescent plastic additives. Moreover, as one of the representatives of bismuth-based compound semiconductors with an Aurivillius-type oxide structure, bismuth oxycarbonate has a typical "sillén" structure, namely (Bi2O2) 2+ Atomic layer, (CO3) 2- A layered structure with alternating atomic layers. 2+ Atomic layer and (CO3) 2- The strong built-in electric field between atomic layers effectively promotes the transfer and separation of photogenerated electron-hole pairs, resulting in superior photocatalytic performance. Existing research has shown that when applied to wastewater treatment, bismuth oxycarbonate can efficiently photocatalytically degrade organic pollutants (such as rhodamine B and methylene blue) in water, making it a potentially excellent photocatalytic material.

[0004] However, the current method for preparing bismuth oxycarbonate mainly uses trivalent bismuth salts as raw materials through a homogeneous solution method. Although this method can produce bismuth oxycarbonate, the product particles tend to agglomerate due to the homogeneous solution reaction, making it difficult to control the target product with minimal aggregation and uniform particle size distribution.

[0005] Therefore, a new preparation method for bismuth oxycarbonate (Bi2O2CO3) needs to be developed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface, which can reduce the agglomeration of product particles and has a simple and easy-to-control preparation process.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] A method for preparing Bi2O2CO3 nanosheets through an in-situ redox reaction at a self-templated heterogeneous interface. The method comprises adding water-insoluble NaBiO3·2H2O (sodium bismuthate dihydrate) and water-soluble C3N3(NH2)3 (melamine) to a hydrothermal reactor containing distilled water and stirring them uniformly to obtain a solid-liquid mixture. Under hydrothermal conditions, the solid-liquid mixture undergoes an in-situ redox reaction at a self-templated heterogeneous interface to prepare Bi2O2CO3 nanosheets. In the reaction, NaBiO3·2H2O serves as a bismuth source and also serves as an oxidant and a solid template. The reaction process is as follows:

[0009]

[0010] As one of the preferred embodiments of the present invention, the molar ratio of NaBiO3·2H2O and C3N3(NH2)3 is 1:1.

[0011] As one of the preferred embodiments of the present invention, the solid-liquid mixture is reacted under hydrothermal conditions at 180-200° C. for 10-30 hours.

[0012] As one of the preferred embodiments of the present invention, after the hydrothermal reaction, the reaction product is centrifuged, washed with distilled water and vacuum dried to obtain the target Bi2O2CO3 nanosheets.

[0013] As one of the preferred embodiments of the present invention, the vacuum drying conditions are: 60° C., 0.1 MPa vacuum degree, and vacuum drying for 2 hours.

[0014] As one of the preferred embodiments of the present invention, the thickness of the Bi2O2CO3 nanosheets is 10 to 15 nm.

[0015] As one of the preferred embodiments of the present invention, in the Bi2O2CO3 nanosheets, the average grain size of Bi2O2CO3 is 73.1 to 93.7 nm.

[0016] Reaction principle:

[0017] Since sodium bismuth dihydrate is an insoluble solid substance, the "heterogeneous redox reaction of sodium bismuth dihydrate and melamine solution" occurs on the solid surface of sodium bismuth dihydrate. During the reaction, sodium bismuth dihydrate is reduced to trivalent bismuth salt by melamine; at the same time, melamine is oxidized by sodium bismuth and produces carbonate ions. The trivalent bismuth salt and carbonate ions are immediately converted into bismuth oxycarbonate in situ and deposited on the surface of the sodium bismuth dihydrate solid template; in the above reaction process, sodium bismuth dihydrate acts as both an oxidant and a sacrificial template agent. As the redox reaction between sodium bismuth dihydrate and melamine continues, the sodium bismuth dihydrate is eventually converted into bismuth oxycarbonate in situ, thereby preparing bismuth oxycarbonate nanosheets.

[0018] The advantages of the present invention over the prior art are:

[0019] (1) The present invention adopts the in-situ redox reaction preparation technology of the self-templated heterogeneous interface, which can reduce the agglomeration of product particles (in-situ conversion deposition on the solid surface can inhibit the migration of product particles and reduce polymerization agglomeration), and the preparation process is simple and easy to control;

[0020] (2) In the preparation of the present invention, sodium bismuthate dihydrate (NaBiO3·2H2O) not only provides a bismuth source for the reaction, but also serves as an oxidant and a solid template. Therefore, the present invention does not require the addition of additional redox agents and templates, thereby improving the purity of the product and meeting the requirements of green material synthesis.

[0021] (3) In the preparation method of the present invention, the raw materials are cheap and easily available, the process is simple, the operation is reliable, and it is easy to industrialize production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the product of Example 2 of the present invention;

[0023] Figure 2 The XRD patterns of the products of various embodiments of the present invention are shown in FIG. 1 (with the XRD pattern of bismuth oxycarbonate as a reference). DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are described in detail. These embodiments are implemented based on the technical solutions of the present invention, and detailed implementation methods and specific operating procedures are given. However, the scope of protection of the present invention is not limited to the following embodiments. At the same time, the reagents and experimental methods used in the following examples and experimental examples are conventional reagents or methods in the art unless otherwise specified, and will not be repeated here.

[0025] Example 1

[0026] A method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface in this embodiment:

[0027] 0.01 mol of NaBiO3·2H2O (sodium bismuthate dihydrate) and 0.01 mol of C3N3(NH2)3 (melamine) were weighed in a 1:1 molar ratio and added simultaneously to a 50 ml hydrothermal reactor containing 40 ml of distilled water. The mixture was stirred evenly to obtain a solid-liquid mixture. The mixture was then sealed and hydrothermally reacted at 180°C for 10 hours. Bi2O2CO3 was generated through an in situ redox reaction at the template's heterogeneous interface. The reaction product was centrifuged, washed with distilled water, and vacuum dried at 60°C and 0.1 MPa for 2 hours to obtain Bi2O2CO3 nanosheets.

[0028] In the above-mentioned "self-templated heterogeneous interface in situ redox reaction", NaBiO3·2H2O is used as the bismuth source. At the same time, NaBiO3·2H2O also serves as the oxidant and solid template. The reaction process is as follows:

[0029]

[0030] Example 2

[0031] The method of preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface in this embodiment is basically the same as that in Example 1, with the main difference being that the solid-liquid mixture is reacted under hydrothermal conditions at 190°C for 10 hours.

[0032] Example 3

[0033] The method of preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface in this embodiment is basically the same as that in Example 1, with the main difference being that the solid-liquid mixture is reacted under hydrothermal conditions at 190°C for 20 hours.

[0034] Example 4

[0035] The method of preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a template heterogeneous interface in this embodiment is basically the same as that in Example 1, with the main difference being that the solid-liquid mixture is reacted under hydrothermal conditions at 190°C for 30 hours.

[0036] Example 5

[0037] The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface in this embodiment is basically the same as that in Example 1, with the main difference being that the solid-liquid mixture is reacted under hydrothermal conditions at 200°C for 10 hours.

[0038] Experimental Example 1

[0039] The product obtained in the above embodiment (taking embodiment 2 as an example) was observed under a scanning electron microscope (SEM), and the results were as follows: Figure 1 shown.

[0040] from Figure 1 It can be seen that the obtained product is in the form of nanosheets, and the thickness of the nanosheets is about 10 to 15 nm.

[0041] Experimental Example 2

[0042] The product obtained in the above embodiment was subjected to X-ray diffraction analysis (XRD analysis), and the results were as follows: Figure 2 shown.

[0043] Figure 2The XRD patterns of the products prepared in various embodiments of the present invention are shown in Table 1, with bismuth oxycarbonate (PDF#04-009-8533) as a reference. Figure 2 It can be seen that in the XRD patterns of the products of various embodiments of the present invention, only the characteristic diffraction peak of bismuth oxycarbonate (Bi2O2CO3) is present, and no diffraction peaks of other phases are present, indicating that after a certain period of hydrothermal reaction, sodium bismuthate (NaBiO3) is reduced by melamine (C3N3(NH2)3) and converted into bismuth oxycarbonate (Bi2O2CO3).

[0044] At the same time, according to the XRD analysis of the products of the above examples, the average grain size of bismuth oxycarbonate (Bi2O2CO3) in the products of each example was obtained by calculation using the Scherrer formula, as shown in Table 1.

[0045] Table 1 Average crystal size of bismuth oxycarbonate in the products of each example

[0046]

[0047]

[0048] Analysis of the above results:

[0049] (1) When NaBiO3·2H2O and C3N3(NH2)3 were added to distilled water in a molar ratio of 1:1 and hydrothermally reacted at 190℃ for 10h, 20h, and 30h, respectively, the average grain sizes of Bi2O2CO3 in the obtained products were 81.3nm, 85.2nm, and 88.1nm, respectively, indicating that the average grain size of Bi2O2CO3 gradually increased with the extension of the hydrothermal reaction time.

[0050] (2) When NaBiO3·2H2O and C3N3(NH2)3 were added to distilled water in a molar ratio of 1:1 and hydrothermally reacted at 180℃, 190℃ and 200℃ for 10 h, the average grain sizes of Bi2O2CO3 in the obtained products were 73.1nm, 81.3nm and 93.7nm, respectively, indicating that the average grain size of Bi2O2CO3 increased with the increase of hydrothermal reaction temperature.

[0051] Accordingly, during the preparation process, the average grain size of the components in the product can be controlled by appropriately controlling the hydrothermal reaction temperature and reaction time.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing Bi2O2CO3 nanosheets via in-situ redox reaction at a template heterogeneous interface, characterized in that: NaBiO3·2H2O and C3N3(NH2)3 are added to a hydrothermal reactor containing distilled water and stirred uniformly to obtain a solid-liquid mixture. Under hydrothermal conditions, the solid-liquid mixture undergoes an in-situ redox reaction at a self-templated heterogeneous interface to prepare Bi2O2CO3 nanosheets. In the above reaction, NaBiO3·2H2O is used as a bismuth source. At the same time, the NaBiO3·2H2O also serves as an oxidant and a solid template. The reaction process is as follows:

2. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction from a template heterogeneous interface according to claim 1, characterized in that: The molar ratio of NaBiO3·2H2O and C3N3(NH2)3 is 1:

1.

3. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction from a template heterogeneous interface according to claim 1, characterized in that: The solid-liquid mixture is reacted under hydrothermal conditions at 180-200° C. for 10-30 hours.

4. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction from a template heterogeneous interface according to claim 1, characterized in that: After the hydrothermal reaction, the reaction product is centrifuged, washed with distilled water and vacuum dried to obtain the target Bi2O2CO3 nanosheets.

5. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction from a template heterogeneous interface according to claim 4, characterized in that: The vacuum drying conditions are: 60° C., 0.1 MPa vacuum degree, and vacuum drying for 2 h.

6. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a self-templated heterogeneous interface according to any one of claims 1 to 5, characterized in that: The thickness of the Bi2O2CO3 nanosheet is 10-15 nm.

7. The method for preparing Bi2O2CO3 nanosheets by in-situ redox reaction at a template heterogeneous interface according to any one of claims 1 to 5, characterized in that: In the Bi2O2CO3 nanosheets, the average grain size of Bi2O2CO3 is 73.1-93.7 nm.

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