阅读说明：本技术 一种三维海胆状Na-α-MnO2的水热合成方法 (Three-dimensional echinoid Na-alpha-MnO2Hydrothermal synthesis method ) 是由 段晶晶 蓝邦 曹珏然 王楚雄 刘宇宬 李韬 钟楠 冯发达 于 2021-01-28 设计创作，主要内容包括：本发明属于无机纳米材料合成领域,具体涉及一种三维海胆状Na-α-MnO-2的水热合成方法。其包括如下步骤：将一定量的锰盐完全溶解于含有浓硫酸的水溶液中,随后加入一定量的氯酸钠,搅拌均匀分散后水热反应结束后,随后离心、洗涤、干燥。本发明提供的制备方法简单,控制方便,可以通过一步水热反应制备出钠离子孔道填充的α-MnO-2,对α-MnO-2应用领域的拓展意义重大。(The invention belongs to the field of inorganic nano material synthesis, and particularly relates to three-dimensional echinoid Na-alpha-MnO 2 The hydrothermal synthesis method of (1). Which comprises the following steps: completely dissolving a certain amount of manganese salt in an aqueous solution containing concentrated sulfuric acid, then adding a certain amount of sodium chlorate, after the hydrothermal reaction is finished after uniform stirring and dispersion, then centrifuging, washing and drying. The preparation method provided by the invention is simple and convenient to control, and can prepare the alpha-MnO filled with the sodium ion pore canal through one-step hydrothermal reaction 2 For α -MnO 2 The application field has great extension significance.)

1. Three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method is characterized by comprising the following steps: completely dissolving manganese salt in an aqueous solution containing concentrated sulfuric acid, then adding sodium chlorate, after uniformly stirring and dispersing, centrifuging, washing and drying after hydrothermal reaction is finished.

2. The three-dimensional echinoid Na-alpha-MnO of claim 1₂The hydrothermal synthesis method is characterized in that the manganese salt is manganese sulfate.

3. The three-dimensional echinoid Na-alpha-MnO of claim 1 or 2₂The hydrothermal synthesis method is characterized in that the molar ratio of the manganese salt to the sodium chlorate is 1: 1-2.

4. The three-dimensional echinoid Na-alpha-MnO of claim 3₂The hydrothermal synthesis method is characterized in that the volume ratio of the concentrated sulfuric acid to the water is 4-6: 15.

5. The three-dimensional echinoid Na-alpha-MnO of claim 4₂The hydrothermal synthesis method is characterized in that the hydrothermal reaction time is 8-16 h.

6. The three-dimensional echinoid Na-alpha-MnO of claim 5₂The hydrothermal synthesis method is characterized in that the temperature of the hydrothermal reaction is 120-180 ℃.

Technical Field

The invention belongs to the field of inorganic nano material synthesis, and particularly relates to three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method of (1).

Background

Among the many common manganese oxides, manganese dioxide (MnO)₂) The crystal form is the most complex structure and the most crystal form. MnO₂Is manganese oxygen octahedron [ MnO ]₆]Is a structural unit, wherein one Mn is positioned at the central position of an octahedron, 6O are positioned at the vertex angle of the octahedron, octahedron chains are formed among the octahedrons in a co-edge mode, and the octahedron chains form different crystal structures in an edge/vertex combination mode, such as alpha-MnO₂，β-MnO₂,γ-MnO₂,δ-MnO₂And the like. Wherein, alpha-MnO₂Has a 2 × 2 pore channel structure, pore channel size of 0.46nm, and cation (K) in the pore channel⁺、NH₄ ⁺、Ba²⁺Etc.) to maintain the cell structure. alpha-MnO₂The preparation method can influence the species and distribution of the cations in the pore channels, and further influence the activity of the material in different application fields. However, at present, no pore channel is Na⁺alpha-MnO of₂The preparation of (1) is reported.

Researchers have been in MnO₂Much effort has been made in controlling the topography of 3D taraxacum-like structures or other shapes, as these are generally considered to provide unexpected performance compared to functional building blocks. For example, Suib et al utilize MnSO₄And K₂Cr₂O₇Reaction by changing reaction temperature, 3D dandelion-shaped and spherical MnO can be prepared₂And (3) nano materials. Von et al successfully synthesized hollow echinoid alpha-MnO₂They also found that the structural part of sea urchin can be changed by adjusting the pH and temperature of the reaction system. However, MnO in dandelion or other 3D forms₂The template is usually added during the synthesis process to obtain the product, so that the template is inevitably removed after the reaction is finished, and the structure of the material is damaged to some extent. How to oneSynthesizing taraxacum or alpha-MnO with similar appearance without adding any template agent₂And the channel counter ions can be regulated, so that the method is still a great challenge.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention mainly aims to provide three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method of (1). The method synthesizes the alpha-MnO filled with sodium ions in the three-dimensional sea urchin shape by one step through oxidation-reduction reaction under strong acid and hydrothermal conditions₂The preparation method is simple and convenient to control.

In order to achieve the purpose, the invention adopts the following technical scheme:

three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method comprises the following steps:

completely dissolving manganese salt in an aqueous solution containing concentrated sulfuric acid, then adding sodium chlorate, after uniformly stirring and dispersing, centrifuging, washing and drying after hydrothermal reaction is finished.

Preferably, the manganese salt is manganese sulfate.

Preferably, the molar ratio of the manganese salt to the sodium chlorate is 1: 1-2.

Preferably, the volume ratio of the concentrated sulfuric acid to the water is 4-6: 15.

Preferably, the hydrothermal reaction time is 8-16 h.

Preferably, the temperature of the hydrothermal reaction is 120-180 ℃.

Compared with the prior art, the invention has the following beneficial effects:

the preparation method provided by the invention is simple and convenient to control, and can prepare the alpha-MnO filled with the sodium ion pore canal through one-step hydrothermal reaction₂For α -MnO₂The application field has great extension significance.

Drawings

FIG. 1 shows Na-. alpha. -MnO prepared in example 1 of the present invention₂XRD pattern of (a).

FIG. 2 shows Na-. alpha. -MnO prepared in example 1 of the present invention₂Scanning electron micrograph (c).

FIG. 3 shows Na-. alpha. -MnO prepared in example 1 of the present invention₂Transmission electron micrograph (D).

FIG. 4 shows Na-. alpha. -MnO prepared in example 1 of the present invention₂Mapping graph of sodium element.

Detailed Description

The present invention will be described in detail with reference to examples, which are only preferred embodiments of the present invention and are not intended to limit the present invention.

Example 1

Three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method comprises the following steps:

adding 1mmol of MnSO₄Completely dissolved in 15mL of distilled water, 4mL of concentrated sulfuric acid was added, followed by 1.5mmol of NaClO₃Stirring and dissolving completely, carrying out hydrothermal reaction at 140 ℃ for 12h to obtain black precipitate, then carrying out centrifugal washing until filtrate is transparent, and drying to obtain three-dimensional echinoid Na-alpha-MnO₂。

For the Na-alpha-MnO obtained above₂The test characterization is carried out, and the XRD diffraction pattern is shown in figure 1. From the figure, the manganese oxide prepared and the alpha-MnO indicated by JCPDF Standard card PDF #44-0141 are known₂Correspondingly, no other miscellaneous peak exists, which indicates that the alpha-MnO with the pure phase 2x2 structure is synthesized₂And no K is used in the present invention⁺And NH₄ ⁺When the cation exists, only sodium ions exist in the whole reaction system, which shows that only hydrated sodium ions can exist in the pore channel. And the diffraction peak position of the whole body is shifted to a low angle by 0.8 degrees, which shows that the pore channel is enlarged when the pore channel only contains hydrated sodium ions. Na-. alpha. -MnO prepared from this example₂The Na-. alpha. -MnO was observed in the scanning electron micrograph (FIG. 2)₂The sea urchin-shaped sea urchin is in a three-dimensional sea urchin-shaped shape, and the size of the sea urchin is about 3-5 mu m. FIG. 3 is a transmission electron micrograph showing that the sea urchin is composed of nanorods. FIG. 4 is a Mapping chart of the sodium element corresponding to the TEM image of FIG. 3, from which it can be seen that the sodium element is uniformly distributed in the sea urchin, and it can be seen that sodium ions are dispersed in α -MnO₂In the duct of (a).

Example 2

Three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method comprises the following steps:

adding 1mmol of MnSO₄Completely dissolved in 15mL of distilled water, followed by addition of 5mL of concentrated sulfuric acid, followed by addition of 2mmol of NaClO₃Stirring and dissolving completely, carrying out hydrothermal reaction at 120 ℃ for 16h to obtain black precipitate, then carrying out centrifugal washing until filtrate is transparent, and drying to obtain three-dimensional echinoid Na-alpha-MnO₂. The XRD, SEM and TEM of the resulting sample were similar to those of example 1.

Example 3

Three-dimensional echinoid Na-alpha-MnO₂The hydrothermal synthesis method comprises the following steps:

adding 1mmol of MnSO₄Completely dissolved in 15mL of distilled water, 6mL of concentrated sulfuric acid was added, followed by 1mmol of NaClO₃Stirring and dissolving completely, carrying out hydrothermal reaction at 180 ℃ for 8h to obtain black precipitate, then carrying out centrifugal washing until filtrate is transparent, and drying to obtain three-dimensional echinoid Na-alpha-MnO₂. The XRD, SEM and TEM of the resulting sample were similar to those of example 1.

Comparative example 1

-MnO₂The preparation method comprises the following steps:

adding 1mmol of MnSO₄Completely dissolved in 15mL of distilled water, 1mL of concentrated sulfuric acid was added, followed by 1.5mmol of NaClO₃Stirring and dissolving completely, carrying out hydrothermal reaction at 140 ℃ for 12h to obtain black precipitate, then carrying out centrifugal washing until filtrate is transparent, and drying to obtain three-dimensional echinoid gamma-MnO₂。

If the concentration of acid is not enough and no template agent such as potassium ion or ammonium ion is used for induction, the alpha-MnO cannot be formed₂Instead, γ -MnO is formed₂。

The above-mentioned embodiments only express the embodiments of the present invention, and the description is more specific and detailed, but not understood as the limitation of the patent scope of the present invention, but all the technical solutions obtained by using the equivalent substitution or the equivalent transformation should fall within the protection scope of the present invention.