JP5630746B2 - Manganese oxide nanowire-covered structure and method for producing the same - Google Patents

Description

  The present invention relates to a manganese oxide-containing nanowire-covered structure characterized in that a solid substrate surface having an arbitrary shape is densely coated with manganese oxide nanowires, and a method for producing the structure. More specifically, manganese oxide nanowires having a thickness of several tens of nanometers are formed in a bowl shape with a thickness of several micrometers on a solid substrate surface of an arbitrary shape, and the solid substrate surface is densely coated. The present invention relates to a nanowire-covered structure and a method for manufacturing the structure.

  Manganese oxides are attracting a great deal of attention as electronic, optical, and magnetic materials such as magnetic materials, insulators, semiconductors, and conductors by constituting a very diverse phase depending on the degree of freedom of spin, charge, lattice, and orbit . Among them, the potential of manganese oxide is large in lithium batteries and capacitors. Further, it can be widely used as an oxidation catalyst because of the degree of freedom of charge.

  In order to express such physical properties of manganese oxide more efficiently, it is desired to construct it on the nano-order scale. In the case of a nano-sized material, compared to a bulk material, the proportion of atoms on its surface increases rapidly, and chemical and physical properties that are not shown in the bulk state are often expressed.

In the case of manganese oxide, there are relatively many studies on nanostructures as powders. For example, Yuan et al. Reported that γ-MnOOH single-crystal nanowires can be synthesized by using MnO ₂ as a raw material and subjecting it to hydrothermal reaction at 200 ° C. under pressure (see, for example, Non-Patent Document 1). ). It has also been reported that a single crystal nanowire of β-MnO ₂ is obtained by heating the single crystal nanowire of γ-MnOOH thus obtained at a temperature of 300 ° C. or higher. Ramstedt et al. Obtained a nanostructured powder of MnOOH by oxidizing a divalent manganese ion compound with peroxide water (see, for example, Non-Patent Document 2). Cristomomo et al. Obtained powder having a nanostructure of manganese oxide by using KMnO ₄ as a starting material and reducing it (see, for example, Non-Patent Document 3). Gao et al. Obtained γ-MnOOH single crystal nanorods by reducing KMnO ₄ with ethanol (see, for example, Non-Patent Document 4). Zheng et al. Report that β-MnO ₂ single crystal nanotubes can be formed by oxidizing manganese sulfate with NaClO ₃ (see, for example, Non-Patent Document 5). Furthermore, Zhang et al. Obtained sea urchin structure γ-MnOOH nanoparticles by oxidizing MnSO ₄ with hydroperoxide under hot water, or oxidized with K ₂ Cr ₂ O ₇ to obtain sea urchin structure. It has reported that to obtain the alpha-MnO ₂ nanoparticles also (for example, see non-Patent Document 6.).

  As described above, in order to obtain the manganese oxide nanostructured powder, it is basically easy to oxidize or reduce the manganese compound in the high-temperature pressurized solution (autoclave) or change the composition at high temperature, which is relatively easy. However, in order to selectively grow manganese oxide nanostructures on the surface of the substrate and obtain a nanofilm of manganese oxide, the autoclave method required for obtaining these powders is not suitable.

Manufacture of a manganese oxide nanostructure thin film requires special conditions. For example, it has been reported that manganese oxide nanowires are deposited on the surface of a conductive substrate such as silicon, ITO, stainless steel, and graphite by an electrochemical route (see, for example, Non-Patent Document 7). In this method, a conductive base material is immersed in an aqueous MnSO ₄ solution and a pulsed electric field is applied to the liquid to deposit manganese oxide on the surface of the conductive base material. However, the resulting manganese oxide nanowire is not a single composition but a thin film of manganese oxide nanocrystals with different chemical structures. Further, for example, a substrate having an anodized alumina (AAO) nanopore on its surface is used as a work electrode, and the substrate is immersed in an aqueous manganese compound solution, and an electric field is applied, so that AAO nanopores are applied. It has been reported that a thin film in which manganese oxide is deposited and grown into nanorods is obtained (see, for example, Non-Patent Document 8).

  In the production of nanostructure thin films of metal oxides, many researches and developments have been conducted on titanium oxide, zinc oxide, etc., so that nanostructure thin films with complex structures such as nanowires, nanotubes, nanoribbons, and nanorods can be easily produced. It has become. However, there are few studies on manganese oxide nanostructured thin films, and efficient films cannot be obtained without going through an electrochemical route. It is no exaggeration to say that there is no technique for producing a non-electrochemical and bottom-up manganese oxide nanostructure (single crystal nanowire) thin film immersed in a solution. That is, the present situation is that the electrochemical process cannot deposit manganese oxide on the surface of the substrate that does not have conductivity.

Yuan et. al. , Appl. Phys. A80, 743-747, 2005 Ramstedt et. al. , Langmuir, 20, 8224, 2004. Cristomoto et. al. , Chem. Mater. , 19, 1832-1839, 2007 Gao et. al. Inorg. Chem. 48, 6242-6250, 2009 Zheng et. al. , J .; Phys. Chem. B, 109, 16439-16443, 2005 Zhang et. al. , Solid State Communications, 141, 427-430, 2007. Hu et al. , Electrochemistry Communications, 10, 1792-1796, 2008. C. -L. Xu et al. , Journal of Solid State Chemistry, 179, 1351-1355, 2006.

  The problem to be solved by the present invention is a structure in which a solid substrate surface of an arbitrary shape made of a conductive or non-conductive material is densely covered with a single crystalline nanowire of a single composition of manganese oxide In particular, a structure characterized in that a monocrystalline nanowire made of manganese oxide completely covers the surface of a solid substrate like a coral reef and has a stable film even in a large area, and the structure An object of the present invention is to provide a simple and efficient method for producing a product.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have immersed a solid base material having a metal oxide surface layer in an aqueous solution of a divalent manganese ion compound to produce manganese oxide and grow crystals. It was found that the above problems can be solved by controlling the surface of the solid substrate on the surface layer, and the present invention has been completed.

  That is, the present invention provides a manganese oxide nanowire-covered structure in which the metal oxide surface layer (a) of the solid substrate (X) having the metal oxide surface layer (a) is coated with the manganese oxide nanowire (Y). The manganese oxide nanowire (Y) is a nanowire made of a single crystal of a single composition of manganese oxide, and a manganese oxide nanowire-covered structure is provided.

Furthermore, the present invention provides (1) a step of preparing an aqueous solution containing a divalent manganese ion compound (i) and hydrogen peroxide,
(2) adding a basic organic amine compound (ii) to the aqueous solution obtained in step (1),
(3) The solid substrate (X) having the metal oxide surface layer (a) is immersed in the aqueous solution obtained in the step (2), heated to 95 ° C. or less, and the metal oxide surface layer (a) Coating the surface with manganese oxide nanowires (Y);
(4) A step of taking out the solid substrate (X) coated with the manganese oxide nanowire (Y), washing the surface with water and drying,
Manufacturing method of manganese oxide MnOOH (y1) nanowire-covered structure characterized by having manganese oxide MnO ₂ (y2) nanowire-covered structure and manganese oxide obtained by firing this A method for producing a Mn ₂ O ₃ (y3) nanowire-covered structure is also provided.

  The manganese oxide nanowire-covered structure of the present invention can be formed by the production method of the present invention as long as there is a metal oxide surface layer such as tin oxide or titanium oxide on an arbitrary shape and surface of an arbitrary material. That is, regardless of the type of the solid substrate, if the surface of the metal oxide can be present on the surface, the surface can be densely coated with the manganese oxide nanowires. Therefore, the structure obtained by the present invention includes various micro battery constructions, catalyst-provided microreactors, chips, sensors, photonic device constructions, insulator or semiconductor constructions, sterilization / sterilization device constructions, and refractive index adjustment of the substrate surface. It can be applied to a wide range of industrial fields such as technology.

2 is a scanning electron micrograph of the glass substrate surface obtained in Synthesis Example 1. FIG. Titanium oxide grains cover the surface. 4 is a scanning electron micrograph of the glass substrate surface obtained in Synthesis Example 2. FIG. Image of substrate surface (left) and cross section (right). The surface is covered with a needle-like structure. 4 is a scanning electron micrograph of the surface of a polymethyl methacrylate substrate obtained in Synthesis Example 3. FIG. The entire substrate surface is covered with a needle-like structure. 2 is a structural cross-sectional scanning electron micrograph obtained in Example 1. FIG. Image of substrate surface (left) and cross section (right). 2 is an XRD diffraction pattern of the structure obtained in Example 1. FIG. 2 is a low-resolution TEM photograph of a nanowire of the structure obtained in Example 1. 2 is a transmission electron micrograph of the nanowire of the structure obtained in Example 1. FIG. Top: one wire image; middle: high resolution image of the full width of one wire; bottom: enlarged view of the middle edge. 3 is a scanning electron micrograph of the cross section of the structure obtained in Example 2. FIG. 3 is an XRD diffraction pattern of the structure obtained in Example 2. FIG. 4 is a scanning electron micrograph of the cross section of the structure obtained in Example 3. FIG. 3 is an XRD diffraction pattern of the structure obtained in Example 3. 4 is a scanning electron micrograph of the structure obtained in Example 4. 6 is a scanning electron micrograph of the structure obtained in Example 5. FIG. 6 is a scanning electron micrograph of the structure obtained in Example 6. FIG.

  The structure of the present invention is a manganese oxide nanowire-covered structure in which the surface of a solid substrate (X) having a metal oxide surface layer (a) is coated with manganese oxide nanowires (Y), The oxide nanowire (Y) forms a certain film on the substrate surface.

  Usually, when a divalent manganese ion compound is dissolved in water and an organic amine compound is added thereto, crystals of manganese oxide tend to precipitate in the solution. Therefore, in order to selectively grow manganese oxide nanowires on the substrate surface, it is a major premise to efficiently “plant” manganese oxide seed crystals, that is, crystal nuclei, on the substrate surface.

  In order to plant crystal nuclei on the surface of a solid substrate, as will be described later, the manganese ion concentration in the solution, the solution temperature, the basic amine compound concentration, the peroxide water concentration, etc. may be prepared. The formation of a dense film of manganese oxide nanowires cannot be induced. The inventor of the present invention focused on the elements essential for the formation of manganese oxide crystal nuclei on the surface of a solid base material in forming a thin film of manganese oxide nanowires. Even if it was a base material, when the metal oxide surface layer existed on the surface, it discovered that manganese oxide nanowire grew highly selectively only on the surface, and it could coat | cover the base material surface completely.

[Solid substrate (X)]
The solid substrate (X) used in the present invention is not particularly limited as long as it has a metal oxide surface layer (a) on its surface. Examples of the material include glass, silicon, metal, and metal oxide. Inorganic materials such as, organic materials such as resin (plastic) and cellulose.

  Examples of the metal oxide constituting the metal oxide surface layer (a) include transition oxides such as tin oxide, titanium oxide, zinc oxide, iron oxide, chromium oxide, nickel oxide, silver oxide, and copper oxide, and foreign matters. These metal oxides doped with Among them, a doped tin oxide thin film having conductivity or a titanium oxide thin film excellent in photoresponsiveness is more preferable. Furthermore, it is more preferable that the conductive tin oxide thin film and the titanium oxide thin film are laminated on the solid substrate (X).

  When the material of the solid substrate (X) is a resin, examples of resin types include polyethylene, polypropylene, polycarbonate, polyester, polystyrene, polymethacrylate, polyvinyl chloride, polyethylene alcohol, polyimide, polyamide, polyurethane, and epoxy resin. Processed products of various polymers such as cellulose can be suitably used.

  The shape of the solid substrate (X) is not particularly limited, and may be a flat or curved plate or a film. In particular, a tubular tube, a spiral tube of a tubular tube, a microtube; a container having an arbitrary shape (for example, a spherical shape, a square shape, a triangular shape, a cylindrical shape); an arbitrary shape (for example, a cylindrical shape, (Rectangle, triangle, etc.) A rod or a solid substrate in a fiber state can also be suitably used.

  As the solid substrate (X) having the metal oxide surface layer (a), commercially available ones can be used as they are, and the metal substrate comprises a metal oxide with respect to the desired solid substrate (X). You may use it, after producing a surface layer. A method for producing a surface layer made of a metal oxide is not particularly limited. For example, a substrate is immersed in a metal oxide source-containing liquid (such as a titanium oxide source liquid, a zinc oxide source liquid, or a tin oxide source). Can be produced.

  Moreover, as a commercial item of solid base material (X) which has a metal oxide surface layer (a) on the surface, for example, indium dope tin oxide (ITO), fluorine dope tin oxide (FTO), antimony dope tin oxide (ATO) etc. Is mentioned.

[Manganese oxide nanowire (Y)]
The structure of the present invention is characterized in that a coating composed of manganese oxide nanowires (Y) is present on the metal oxide surface layer (a) of the solid substrate (X). The nanowire (Y) grows densely in a substantially vertical direction from the surface layer (a) like a coral reef, and forms a nano thin film with a thickness in the range of 1 to 5 μm. The manganese oxide is composed of MnOOH (y1), MnO ₂ (y2), Mn ₂ O ₃ (y3), or the like, and is composed of a single crystal having a single composition.

  The manganese oxide nanowire (Y) in the present invention has a thickness of 10 to 100 nm and a length extending to 1 to 6 μm.

  Further, the manganese oxide nanowire (Y) is characterized in that crystal stripes are arranged in parallel in the length direction of the wire.

  Manganese oxide nanowires (Y) covering the substrate surface are grown in aqueous solution at 100 ° C. or lower, but it is a single component MnOOH (y1), which is highly selectively grown into γ-MnOOH. Features.

When the structure covered with the manganese oxide MnOOH (y1) nanowire is heated at a temperature of 350 ° C. or higher, γ-MnOOH can be completely converted to β- MnO ₂ , and the manganese oxide MnO ₂ (y2) It can be a nanowire-covered structure. In this conversion process (heat treatment process), the nanowire morphology of the manganese oxide is maintained without change.

In addition, γ-MnOOH can be completely converted to α-Mn ₂ O ₃ by heat-treating a structure covered with manganese oxide MnOOH (y1) nanowires at a temperature of 550 ° C. or higher, and manganese oxidation The product Mn ₂ O ₃ (y3) can be a nanowire-covered structure. In this conversion process (heat treatment process), the nanowire morphology of the manganese oxide is maintained without change.

[Method for producing manganese oxide-containing nanowire-covered structure]
Hereafter, the manufacturing method of the structure of this invention is explained in full detail.
In the manufacturing process of the manganese oxide nanowire-covered structure in the present invention, first, the manufacture of a nanowire-covered structure of MnOOH (y1) is a prerequisite.

Manufacture of a manganese oxide MnOOH (y1) -coated structure in the present invention includes the following step (1) step (2) of preparing an aqueous solution containing a divalent manganese ion compound (i) and hydrogen peroxide. Step (3) of adding basic organic amine compound (ii) to the aqueous solution obtained in 1) (3) The solid substrate (X) having the metal oxide surface layer (a) is immersed in the aqueous solution obtained in step (2). Heating to 95 ° C. or lower, and coating the surface of the metal oxide surface layer (a) with manganese oxide nanowires (Y),
(4) A step of taking out the solid substrate (X) coated with the manganese oxide-containing nanowire (Y), washing the surface with water and drying,
It is characterized by having.

[Divalent manganese ionized compound (i)]
In the production method of the present invention, in order to efficiently construct the manganese oxide nanowire (Y), a divalent manganese ion compound (i) is used as an essential precursor. Examples of the compound (i) include manganese nitrate, manganese sulfate, manganese chloride, manganese acetate, and the like.

  The suitable concentration of the divalent manganese ion compound (i) in the step (1) is preferably 1 to 25 mM, more preferably 5 to 20 mM.

  In the step (1), when the divalent manganese ion compound (i) is dissolved, an aqueous solution containing hydrogen peroxide is simultaneously used by using a water peroxide compound. The number of moles is preferably 3 to 4 times the number of moles of (i). In addition, in this process (1), it is preferable to carry out the temperature of aqueous solution at room temperature, for example, the range of 5-30 degreeC.

  In step (2), the basic organic amine compound (ii) is added to the aqueous solution prepared in step (1). As the basic organic amine compound (ii), alkylamines which are primary, secondary and tertiary amines can be suitably used. Also, nitrogen atom-containing cyclic basic organic compounds such as hexamethylenetetramine, pyridine, and imidazole can be suitably used. The amount of the amine compound (ii) used is preferably 1 to 3 times the molar amount of the divalent manganese ion (i) used in the step (i).

[Manufacturing Process of Manganese Oxide MnOOH (y1) Nanowire Covered Structure]
The solid substrate (X) having the metal oxide surface layer (a) is immersed in the aqueous solution obtained in the above step (2) and heated to 95 ° C. or lower as it is using a water bath or the like, so that the surface MnOOH (y1) nanowires can be grown.

  The heating condition is preferably in the range of 30 to 95 ° C, and more preferably in the range of 65 to 90 ° C in order to highly control the degree of elongation of the nanowires.

  Further, the immersion time of the substrate is not particularly limited, but may be in the range of 30 minutes to 10 hours, and is preferably in the range of 2 to 6 hours in order to highly control the degree of elongation of the nanowires.

  After the nanowires are grown under the above-mentioned conditions, the substrate is taken out from the aqueous solution, and the surface is washed with distilled water or the like, or the substrate is immersed in distilled water and washed with water. Then, the manganese oxide MnOOH (y1) nanowire-covered structure can be obtained by drying by standing at room temperature or the like.

[Manufacturing Process of Manganese Oxide MnO ₂ (y2) Nanowire Covered Structure]
The MnOOH (y1) nanowire-covered structure obtained through the above immersion process is subjected to a step of heating the entire substrate, whereby the MnOOH (y1) nanowire can be converted to MnO ₂ (y2) nanowire.

In the heating step, in order to selectively limit the composition conversion of the manganese oxide to MnO ₂ (y2), it is desirable to set the temperature range to 500 ° C. or lower, and usually to improve the crystallinity of MnO ₂ nanowire (y2) It is the range of 300-500 degreeC, and it is more preferable that it is the range of 400-500 degreeC.

The heating time is not particularly limited, but MnOOH (y1) nanowires can be converted to MnO ₂ (y2) nanowires within a range of 30 minutes to several hours within a predetermined compatible temperature range.

  The temperature rise during heating is preferably controlled programmatically, and is preferably raised to a predetermined temperature over several tens of minutes or 1 hour.

[Manufacturing Process of Manganese Oxide Mn ₂ O ₃ (y3) Nanowire Covered Structure]
By treating the MnOOH (y1) nanowire-covered structure or manganese oxide MnO ₂ (y2) nanowire-covered structure obtained above at a higher temperature, the manganese oxide Mn ₂ O ₃ (y3) nanowire coating A mold structure can be obtained.

By setting the heating temperature in the range of 550 to 1000 ° C., a manganese oxide Mn ₂ O ₃ (y3) nanowire-covered structure can be obtained. In order to stably convert to manganese oxide Mn ₂ O ₃ (y3) nanowires, it is more preferable to set the heating temperature in the range of 550 to 650 ° C.

Not that particularly limited heating time at the predetermined temperature range, can be converted from 30 minutes if a few hours, the MnOOH (y1) nanowire or _MnO 2 (y2) nanowires suitably Mn2O ₃ nanowire (y3). It should be noted that the specific device for heating is not limited at all, and general-purpose equipment capable of adjusting the temperature is sufficient.

  Hereinafter, the present invention will be described in more detail with reference to examples. Unless otherwise specified, “%” represents “mass%”.

[Shape analysis of nanowires using a scanning electron microscope]
The dried nanowire was fixed to a sample support with a double-sided tape and observed with a scanning electron microscope “S-5000” manufactured by Hitachi.

[Nanowire shape analysis by transmission electron microscope]
Observation was performed with a transmission electron microscope “JEM-2200FS” manufactured by JEOL Ltd.

[Analysis of Manganese Oxides by X-ray Diffraction (XRD)]
Place manganese oxide on the measurement sample holder, set it on the Rigaku Corporation wide-angle X-ray diffractometer “Rint-ultma”, Cu / Kα ray, 40 kV / 30 mA, scan speed 1.0 ° / min, scan The conditions were in the range of 20-40 °. In particular, in the analysis of the internal structure details of the coating film, the measurement conditions were set as follows. X-ray: Cu / Kα ray, 50 kV / 300 mA, scanning speed: 0.12 ° / min; scanning axis: 2θ (incident angle 0.2 to 0.5 °, 1.0 °).

Synthesis Example 1 [Preparing a titanium oxide surface layer on the surface of a glass substrate]
In a screw glass tube, 0.071 g of TiOSO ₄ · nH ₂ O (titanyl sulfate, manufactured by Nacalai Tesque) colorless powder was dispersed in 19 mL of distilled water (water quality; specific resistance 18.2 mΩ · cm). % Of hydrogen peroxide 60 μL (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. A few drops of nitric acid (69%, manufactured by Kishida Chemical Co., Ltd.) was added to this dispersion, and the mixture was stirred at room temperature for 30 minutes until TiOSO ₄ was completely dissolved. Nitric acid was again added dropwise to this solution to adjust the pH to 1.3, and 0.036 g of sodium carbonate (manufactured by Kishida Chemical Co., Ltd., for pH standard solution) was dissolved to adjust the pH to 1.65. The pH was measured using a pH meter manufactured by Mettler Toledo (Switzerland). The slide glass substrate was soaked and immersed in the aqueous solution of the titanium oxide precursor thus obtained, and allowed to stand at 80 ° C. for 1 hour. After 1 hour, the substrate was taken out and washed with distilled water.

  The substrate was dried and then heated at 400 ° C. for 1 hour. Thus, an anatase-type titanium oxide surface layer was formed on the glass substrate surface (FIG. 1).

Synthesis Example 2 [Producing a titanium oxide surface layer on the surface of a glass substrate]
A slide glass substrate was stood and immersed in the same liquid as in Synthesis Example 1, and the solution was heated to 80 ° C. and allowed to stand at that temperature for 18 hours. After cooling the solution to room temperature, the glass substrate was taken out, washed with distilled water three times, and allowed to stand at room temperature to dry. Thus, the glass substrate surface was covered with turf-like titanium oxide (FIG. 2).

Synthesis Example 3 [Preparing a titanium oxide surface layer on the surface of a polymethyl methacrylate substrate]
A polymethylmethacrylate plate was immersed in the same liquid as in Synthesis Example 1, and the solution was heated to 80 ° C. and allowed to stand at that temperature for 18 hours. After cooling the solution to room temperature, the film substrate was taken out, washed with distilled water three times, and allowed to stand at room temperature to dry. Thus, the polyimide film surface was covered with turf-like titanium oxide (FIG. 3).

Example 1 [Structure in which surface of silicon substrate having tin oxide surface layer is coated with manganese oxide (MnOOH) nanowire]
MilliQ water, Mn (NO ₃ ) ₂ · 6H ₂ O (special grade, Kanto Chemical), H ₂ O ₂ (35%) are sequentially added to the sample bottle, and finally hexamethylenetetramine (special grade, Kishida Chemical) is dissolved. The composition of the compound was prepared as a solution of manganese ions (15 mmol / L), H ₂ O ₂ (37 mmol / L), and hexamethylenetetramine (15 mmol / L). A silicon substrate having a fluorine-doped tin oxide surface layer (FTO, manufactured by AGC Fabrictech) was immersed in the solution, and allowed to stand at 80 ° C. for 5 hours.

  The substrate was taken out, washed three times with distilled water, and then dried at room temperature to obtain a silicon structure covered with MnOOH nanowires. FIG. 4 shows a cross-sectional structure photograph of the obtained structure by SEM observation. The state where the nanowires are densely arranged on the substrate is clearly observed. XRD observation of this structure revealed that the wire was a crystal derived from γ-MnOOH (FIG. 5). Furthermore, the wire was scraped off and the wire was observed with TEM. From observation under low-resolution conditions, the wire surface was slightly rough and its thickness was 30 nm (FIG. 6). Under high resolution conditions, nanowire crystal lattice stripes were observed, and the stripes of the same interval extended in one direction (FIG. 7). This strongly suggests that the γ-MnOOH nanowire is a single crystal.

Example 2 [Structure in which the surface of a silicon substrate having a tin oxide surface layer is coated with manganese oxide (MnO ₂ ) nanowires]
The MnOOH nanowire-covered structure obtained in Example 1 was placed in an electric furnace and left under heating at 400 ° C. for 1 hour. After cooling, the sample was removed to obtain a MnO ₂ nanowire-covered structure. An SEM photograph of this structure is shown in FIG. The wire structure did not change, and the dense coating structure remained. From the XRD measurement of the structure, it was suggested that the nanowire is a crystal derived from MnO ₂ (FIG. 9).

Example 3 [Structure in which the surface of a silicon substrate having a tin oxide surface layer is coated with manganese oxide (Mn ₂ O ₃ ) nanowires]
The MnOOH nanowire-covered structure obtained in Example 1 was placed in an electric furnace and left under heating at 600 ° C. for 1 hour. After cooling, a sample was taken out to obtain a Mn ₂ O ₃ nanowire-covered structure. An SEM photograph of this structure is shown in FIG. The wire structure did not change, and the dense coating structure remained. From the XRD measurement of the outer structure, it was suggested that the nanowire is a crystal derived from Mn ₂ O ₃ (FIG. 11).

Example 4 [Structure in which surface of glass substrate having titanium oxide surface layer is coated with manganese oxide (MnOOH) nanowire]
The glass substrate having the titanium oxide surface layer obtained in Synthesis Example 1 was treated in the same manner as in Example 1 to obtain a manganese oxide MnOOH nanowire-covered structure.

  From the SEM observation, a cage-like structure in which nanowires were densely coated on the substrate surface was confirmed (FIG. 12).

Example 5 [Structure in which surface of glass substrate having titanium oxide surface layer is coated with manganese oxide (MnOOH) nanowire]
The glass substrate having the titanium oxide surface layer obtained in Synthesis Example 2 was treated in the same manner as in Example 1 to obtain a manganese oxide MnOOH nanowire-covered structure.

  From the SEM observation, a cage-like structure in which nanowires were densely coated on the substrate surface was confirmed (FIG. 13).

Example 6 [Structure in which surface of polymethyl methacrylate (PMMA) substrate having titanium oxide surface layer is coated with manganese oxide (MnOOH) nanowire]
The PMMA substrate having the titanium oxide surface layer obtained in Synthesis Example 3 was treated in the same manner as in Example 1 to obtain a manganese oxide MnOOH nanowire-covered structure.

  From the SEM observation, a cage-like structure in which nanowires were densely coated on the substrate surface was confirmed (FIG. 14).

  Manganese oxide nanowire-covered structure of the present invention includes various micro battery construction, catalyst-provided microreactor, sensor, optical device construction, photothermal conversion device, infrared absorber, insulator or semiconductor construction, sterilization / sterilization device construction It can be used as a superhydrophilic / superhydrophobic interface construction.

Claims (7)

Manganese oxide nanowire formed by coating the metal oxide surface layer (a) of the solid substrate (X) having a tin oxide thin film or a titanium oxide thin film as the metal oxide surface layer (a) with the manganese oxide nanowire (Y). A covered structure,
A manganese oxide nanowire-covered structure, wherein the manganese oxide nanowire (Y) is a nanowire made of a single crystal having a single composition of manganese oxide. The manganese oxide of manganese oxide nanowires (Y) _{is, MnOOH (y1), MnO 2} (y2) or _Mn 2 _O 3 (y3) a is claim 1 manganese oxide nanowire-covered structure according. The manganese oxide nanowire-covered structure according to claim 1 or 2, wherein the manganese oxide nanowire (Y) has a thickness in the range of 10 to 100 nm and a length in the range of 1 to 6 µm. The manganese oxide nanowire-covered structure according to any one of claims 1 to 3, wherein the manganese oxide nanowire (Y) covers the metal oxide surface layer (a) so as to stand in a substantially vertical direction. (1) a step of preparing an aqueous solution containing a divalent manganese ion compound (i) and hydrogen peroxide;
(2) adding a basic organic amine compound (ii) to the aqueous solution obtained in step (1),
(3) The solid substrate (X) having the metal oxide surface layer (a) is immersed in the aqueous solution obtained in the step (2), heated to 95 ° C. or less, and the metal oxide surface layer (a) Coating the surface with manganese oxide nanowires (Y);
(4) A step of taking out the solid substrate (X) coated with the manganese oxide nanowire (Y), washing the surface with water and drying,
A method for producing a manganese oxide MnOOH (y1) nanowire-covered structure characterized by comprising: The manganese oxide MnOOH (y1) nanowire-covered structure obtained in the steps (1) to (4) of claim 5 has a step of heating in a temperature range of 300 to 500 ° C. Manganese oxide MnO ₂ (y2) A method for producing a nanowire-covered structure. The manganese oxide MnOOH (y1) nanowire-covered structure obtained in the steps (1) to (4) of claim 5 , or a manganese oxide obtained by heating the manganese oxide in a temperature range of 300 to 500 ° C. A method for producing a manganese oxide Mn ₂ O ₃ (y3) nanowire-covered structure, comprising heating the MnO ₂ (y2) nanowire-covered structure in a temperature range of 550 to 1000 ° C.

Images