KR102005410B1 - Manufacturing method of ordered mesoporous manganese oxide by electrochemical deposition - Google Patents

Abstract

More particularly, the present invention relates to a method for preparing a manganese oxide having an ordered mesoporous structure by adding a surfactant to an electrolyte comprising a manganese oxide precursor, To obtain an electrode having mesoporous manganese oxide formed thereon.
The manganese oxide having the aligned mesoporous characteristics prepared according to the present invention can exhibit higher activity than the conventional catalyst as a reaction catalyst because the contact with the reactant is larger than that of the conventional reaction catalyst material.

Description

Technical Field [0001] The present invention relates to a method for preparing an ordered mesoporous manganese oxide by electrodeposition,

The present invention relates to a method for preparing a manganese oxide having an aligned mesoporous structure using an electrodeposition process.

The catalytic or electrochemical reactions are mainly heterogeneous. In the heterogeneous reaction, the reaction occurs on the catalyst surface because the reactant and the phase of the catalyst on which the reaction occurs differ. In this case, the reactant is mainly a gas or a liquid fluid, and the contact between the fluid and the solid greatly affects the activity of the reaction, so that the surface area of the catalyst also affects the activity of the catalyst.

In the catalytic material, the porous material having pores developed therein has a large surface area, so that the contact with the reactant is advantageous. Among the porous materials, the aligned mesoporous material can easily penetrate the fluid with a pore size of between 2 and 50 nm, and when used as an electrode, increases the contact area between the electrolyte and the electrode due to its high surface area It has attracted attention because of its advantages.

A generally used method for increasing the surface area of an oxide catalyst is to increase the surface area by forming a one-dimensional structure or a porous structure. In this process, a hydrothermal synthesis or a precipitation method is used to form a one-dimensional structure or a porous structure, and a specific structure is induced by adding a surfactant to the synthesis solution.

Specifically, mesoporous materials can be synthesized by hydrothermal reaction using organic molecules such as surfactants and ampholytic polymers as structure inducing materials. In this case, the surfactant and the ampholytic polymer are composed of a hydrophilic head and a hydrophobic tail, thereby forming a micellar or liquid crystal structure of various structures through self-assembly in an aqueous solution, Can be used to synthesize the desired mesoporous material.

In addition, since surfactants can have various liquid crystal structures depending on the concentration and temperature in an aqueous solution, if a synthesis condition is changed, a variety of materials can be synthesized from a surfactant, and depending on the shape of the molecules, This has the advantage.

However, since the micelle structure of the surfactant must be dissolved in the solution at a high concentration in the hydrothermal synthesis method, an excessive amount of surfactant is required, and a method of obtaining an oxide at high temperature and pressure requires high heat energy, There are disadvantages.

In addition, when mesoporous materials are synthesized by hydrothermal synthesis or precipitation, they are synthesized in the form of powder. Therefore, additional processes such as slurrying and spray coating are needed to use them as electrodes.

On the other hand, in the case of the electrodeposition method, a rapid deposition process is possible on the surface of a substance to be deposited through the oxidation or reduction reaction of ions, and a uniform oxide layer can be introduced.

In general, transition metals are very useful for redox reactions due to their various oxidation states, and they are used as catalysts for electrode materials and energy conversion reactions of energy storage devices. Among many transition metals, manganese oxides can be present as oxides such as MnO, MnO ₂ , and Mn ₂ O ₃ , exhibiting high activity in the reaction, low production cost, and being a naturally friendly substance.

Due to the above-mentioned reasons, researches on the development and improvement of processes capable of producing manganese oxide have been continuously carried out.

Next, a brief description will be given of the prior arts existing in the field to which the technology of the present invention belongs, and the technical matters to be differentiated from the prior arts of the present invention will be described.

Korean Patent No. 10-1424680 (Apr. 23, 2014) discloses a method of manufacturing an electrode for a supercapacitor, and more particularly, to a method of manufacturing an electrode for a supercapacitor, And a method for preparing a metal oxide layer having a fiber structure by controlling the dispersion degree of a metal precursor by adding a surfactant. (Patent Document 0001)

However, the prior art does not describe the fact that an electrode coated with a metal oxide is produced by a method of electro-depositing at room temperature (20 to 30 ° C), and the metal oxide structure thus obtained has a mesoporous form.

Korean Patent No. 10-0819870 (Mar. 31, 2008) is directed to a method for producing a thin film using an electrochemical deposition method, and more particularly, to an aqueous solution containing a cetyltrimethylammonium bromide (CTAB) powder as a surfactant The present invention relates to a process for producing a vanadium pentoxide thin film by electrochemical deposition using an electrolyte solution prepared by controlling pH conditions of a vanadium pentoxide thin film. (Patent Document 0002)

Korean Patent No. 10-0970575 (July 10, 2010) also relates to a method for producing a thin film using an electrochemical vapor deposition method, and more particularly, to an electrolyte comprising a surfactant such as cetyltrimethylammonium bromide (CTAB) A technique for preparing a ruthenium dioxide thin film having a mesoporous structure by an electrochemical deposition method after immersing a substrate in a solution. (Patent Document 0003)

More specifically, cobalt sulfate powder is dissolved in distilled water and then cetyltrimethylammonium bromide (CTAB) is added to the solution. ) Is used as a structural culture material to produce a cobalt tetraoxide tetraoxide having a uniform mesoporous structure. (Patent Document 0004)

In the above Patent Documents 2 to 4, metal oxide thin films were prepared by electro-deposition using an electrolyte added with cetyltrimethylammonium bromide (CTAB), which is a structural culture material. Particularly, in Comparative Example 2 of Patent Document 4, the physical properties of a cobalt tetraoxide tetroxide film prepared by an electrodeposition method using an electrolyte containing sodium dodecylsulfate (SDS), which is a kind of surfactant, as a structural culture material were measured. As a result, the mesoporous structure formed in the washing process collapsed, causing problems such as that the peak was weakened after washing in the x-ray diffraction analysis.

Thus, it has been found that the parameters such as the type, concentration, and temperature of the surfactant should be set differently depending on the target material to which the method of electrodeposition using the surfactant is used as the structural culture material, and the production of the manganese oxide thin film As a result of repeated studies on the method, the present invention has been achieved.

Korean Patent No. 10-1424680 Korean Patent No. 10-0819870 Korean Patent No. 10-0970575 Korean Patent No. 10-0918845

The hydrothermal synthesis requires a high temperature. When the hydrothermal synthesis method and the precipitation method are used, it takes a long time to synthesize and it is synthesized in powder form. Therefore, an additional process such as slurry method or spray coating is further needed for use as an electrode. Also, in this case, an excessive amount of surfactant is required, and accordingly, the types of structures that can be formed are limited.

In order to solve the above problems, there is provided a method of preparing a mesoporous manganese oxide arranged by using an electrodeposition method using an electrolyte prepared by adding a surfactant as a precursor of manganese and a templating agent.

One embodiment of the present invention relates to a method for preparing an electrolyte comprising: (a) dissolving a manganese precursor and sodium dodecylsulfate (SDS) in distilled water to prepare an electrolyte; (b) electrodeposition the manganese hydroxide by applying a voltage in the range of -1.0 to -1.8 V in the temperature range of 65 to 75 ° C using the electrode system including the working electrode and the counter electrode to the electrolyte prepared in the step (a) step; (c) heat treating the working electrode deposited with manganese hydroxide in the step (b) to obtain a working electrode coated with manganese oxide; (d) washing and removing impurities remaining in the working electrode obtained in the step (c); And (e) drying the working electrode obtained in the step (d). The present invention also provides a method for producing a manganese oxide having an ordered mesoporous structure.

In a preferred embodiment of the present invention, the nitric acid precursor of step (a) is manganese nitrate (Mn (NO ₃ ) ₂ ) and the manganese nitrate (Mn (NO ₃ ) ₂ ) have.

In a preferred embodiment of the present invention, the sodium dodecyl sulfate of step (a) may be added in an amount of 0.5 to 3% by weight.

In a preferred embodiment of the present invention, the electrolyte is further comprised of cetyltrimethylammonobomide (CTAB) in the step (a), and the cetyltrimethylammonobromide may range from 0.005 to 0.3 wt% .

In a preferred embodiment of the present invention, the electrolyte further comprises ethylene glycol in the step (a), and ethylene glycol may be added to the distilled water at a weight ratio of 30% or less.

In a preferred embodiment of the present invention, the heat treatment in step (c) may be performed at a temperature of 200 to 500 ° C for 3 hours or more.

Another embodiment of the present invention provides a manganese oxide having an ordered mesoporous structure produced by the above process.

The manganese oxides of the aligned mesoporous structures synthesized according to the above method are superior in contact with the reactants than the manganese oxides of the unaligned mesoporous structure and exhibit higher activity when applied to the reaction catalyst or the electrode material.

The present invention has a short synthesis time and does not require an additional process to attach the manganese oxide to the electrode surface. In addition, adsorption of the surfactant can be induced by using a small amount of surfactant, and various types of porous structures can be synthesized by controlling the temperature of the additives and the solution.

In addition, the present invention can induce deformation of the structure by forming manganese oxide of mesoporous structure aligned using semi-micelles adsorbed on the surface, and adding other additives. In addition, this structure is formed from the surface to the inside, thereby increasing the surface area and facilitating the mass transfer of the electrolyte.

1 is a photograph of a manganese oxide deposited in Example 1 according to the present invention by a transmission electron microscope (TEM).
2 is a photograph of a manganese oxide deposited in Example 2 by a transmission electron microscope (TEM).
3 is a photograph of a manganese oxide deposited in Example 3 by a transmission electron microscope (TEM).
4 is a photograph of a manganese oxide deposited in Comparative Example 1 by a transmission electron microscope (TEM).
5 is a photograph of a manganese oxide deposited in Comparative Example 2 by a transmission electron microscope (TEM).
6 is a photograph of X-ray diffraction pattern (XRD) observed at a low angle of manganese oxide deposited in Example 1 according to the present invention.
7 is a photograph of the X-ray diffraction pattern (XRD) observed at a low angle of manganese oxide deposited in Example 2 according to the present invention.
FIG. 8 is a photograph of X-ray diffraction pattern (XRD) observed at a low angle of manganese oxide deposited in Example 3 according to the present invention.
FIG. 9 is a photograph of X-ray diffraction pattern (XRD) of manganese oxide deposited at Comparative Example 1 according to the present invention at a low angle.
10 is a photograph of X-ray diffraction pattern (XRD) observed at a low angle of manganese oxide deposited in Comparative Example 2 according to the present invention.
11 is a photograph showing the results of a photoelectron spectrometer of manganese oxide deposited in Example 1 according to the present invention.
12 is a graph showing cyclic voltammetry results of 0.5 M Na ₂ SO ₄ of manganese oxide deposited in Examples 1, 2 and 3 and Comparative Example 1 according to the present invention.
13 is a graph showing charge-discharge curve results of 0.5 M Na ₂ SO ₄ of manganese oxide deposited in Examples 1, 2 and 3 and Comparative Example 1 according to the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, the aligned mesoporous manganese oxide deposition method according to the present invention will be described in detail in each step.

The process for preparing the aligned mesoporous manganese oxide according to the present invention is as follows.

(A) dissolving a manganese precursor and sodium dodecyl sulfate (SDS) in distilled water to prepare an electrolyte; (b) electrodeposition the manganese hydroxide by applying a voltage in the range of -1.0 to -1.8 V in the temperature range of 65 to 75 ° C using the electrode system including the working electrode and the counter electrode to the electrolyte prepared in the step (a) step; (c) heat treating the working electrode deposited with manganese hydroxide in the step (b) to obtain a working electrode coated with manganese oxide; (d) washing and removing impurities remaining in the working electrode obtained in the step (c); And (e) drying the working electrode obtained in step (d). The method of manufacturing a manganese oxide having an ordered mesoporous structure according to claim 1,

The surfactant is used as a template agent. In the present invention, a template agent is a material that provides a function of widening the specific surface area of manganese oxide by forming a specific structure on the surface when manganese hydroxide is deposited.

Depending on the concentration of the surfactant and the temperature of the electrolyte, other forms and sizes of semi-micelles are formed on the surface of the electrode, and deposition occurs on the semi-micelles formed during the electroplating. When the semi-micelle is removed from the deposited thin film, a mesoporous manganese oxide is obtained.

In the present invention, sodium dodecyl sulfate (SDS) or cetyltrimethylammonium bromide (CTAB) is used as a surfactant.

To explain step (a), sodium dodecyl sulfate (SDS) and a manganese precursor are sequentially dissolved in distilled water to prepare an electrolyte.

First, sodium dodecyl sulfate is dissolved in distilled water, and the concentration of sodium dodecyl sulfate is preferably 0.5-3 wt%. When sodium dodecyl sulfate is added in an amount of less than 0.5% by weight, no semi-micelles are formed. When the amount of sodium dodecyl sulfate is more than 3% by weight, deposition of manganese does not occur.

Thereafter, the manganese precursor is dissolved in distilled water, and manganese nitrate (Mn (NO ₃ ) ₂ ) is preferably used as the manganese precursor. At this time, the concentration of manganese nitrate (Mn (NO3) 2) is preferably 0.005 to 0.05M. When the manganese nitrate is less than 0.005 M, the deposition rate is too slow to synthesize the mesoporous structure. If the manganese nitrate is more than 0.05 M, it is difficult to form a uniform thin film structure.

As the precursor of manganese, manganese sulfate, manganese acetate, etc. may be used in addition to manganese nitrate. However, when a precursor other than manganese nitrate is used, a substance containing nitrate ions such as sodium nitrate or potassium nitrate must be added in order to generate hydroxide ions at the reduction potential. Manganese nitrate is easy to use because it does not contain added substances.

In addition, the step (a) may further include cetyltrimethylammonobomide (CTAB) to prepare an electrolyte in which manganese precursor, sodium dodecyl sulfate and cetyltrimethylammonobromide are dissolved in distilled water. The addition of a small amount of cetyltrimethylammonobromide with charge opposite to that of sodium dodecyl sulfate results in an interaction between sodium dodecyl sulfate and cetyltrimethylammonobromide, - Can change the structure of the micelle.

The addition amount of cetyltrimethylammonobromide is preferably 0.005 to 0.3% by weight. When cetyltrimethylammonobromide is added at less than 0.005% by weight, insufficient interaction between sodium dodecylsulfate and cetyltrimethylammonobromide is not formed, so that it is impossible to induce a change in structure, and when 0.3% by weight is exceeded, the deposition reaction is inhibited The deposition of manganese does not occur properly.

In addition, ethylene glycol may be added to the electrolyte in addition to distilled water to assist the growth of the structure. Ethylene glycol added to the electrolyte solution penetrates into the semi-micelles of sodium dodecyl sulfate to change the structure of the semi-micelles and is effective for obtaining manganese oxides of mesoporous structure.

At this time, it is preferable that ethylene glycol is added to the distilled water at a weight ratio of 30% or less. When the amount of ethylene glycol is more than 30 wt%, the viscosity of the electrolyte is increased and the mass transfer rate of manganese ions is slowed, so that the deposition reaction can not be performed properly.

In the step (b), the working electrode is not particularly limited, but preferably ITO glass, stainless steel, platinum or the like may be used, and the electrode may further be washed to use an electrode to be deposited. As the counter electrode, one selected from the group consisting of a platinum electrode, a platinum mesh electrode, and a platinum wire electrode may be used. In addition, the electrodeposition may be performed using a three-electrode system including a reference electrode, and it is preferable to use a silver-silver chloride reference electrode as a reference electrode.

The solution used for washing may be a mixed solution of C ₁ -C ₄ alcohol and acetone, preferably a 1: 1 mixed solution of isopropanol and acetone.

In the step of electrodepositing the manganese hydroxide of the step (b), the temperature of the electrolyte is preferably maintained at 65 to 75 ° C. When the electrolyte temperature is lower than 65 ° C or above 75 ° C, the semi-micelles are not properly formed and the mesoporous structure does not appear.

In the step (b), the potential during deposition is preferably -1 to -1.6 V (vs Ag / AgCl (3M)). The electrostatic method is a method in which a potential is constantly applied to the working electrode over time, and the current flowing through the electrode changes with time. When the electrostatic deposition method is used in electrodeposition, the potential to be injected into the working electrode is constant and the addition reaction other than the deposition reaction is less.

When the metal oxide is deposited at the reduction potential, an electrolyte containing NO ₃ ^- is used in the electrolyte, thereby generating OH ^- on the surface of the substance to be deposited before the metal ion is deposited. The reaction in which OH ^- is generated is shown in the following reaction formula (1).

OH ^- Formation reaction: NO ₃ ^- + 6H ₂ O + 8e ^- → NO ₂ ^- + 9OH ^- (1)

The resulting OH ^- and metal ions react with each other to form a hydroxide compound in the surface of the electrode. The reaction scheme for manganese is shown in the following reaction formula (2).

Manganese hydroxide formation reaction formula: Mn ^{+ 2} + 2OH ^- → Mn (OH) ₂ (2)

The generated manganese hydroxide is subjected to heat treatment to remove water from the manganese oxide.

In the step (c), it is preferable that the electrode on which the manganese hydroxide obtained in the step (b) is deposited is subjected to heat treatment at a temperature of 200 to 500 ° C for 3 hours or more. When the heat treatment temperature is less than 200 ° C, manganese oxides are not formed because water is not removed in the structure of manganese hydroxide, and when the temperature exceeds 500 ° C, the mesoporous structure formed is collapsed.

In the step (d), the electrode prepared in the step (c) is preferably immersed in one selected from the group consisting of ethanol, isopropanol, acetone and the like for 15 to 24 hours to remove the surfactant on the electrode surface. If the cleaning time is less than 15 hours, the residual surfactant in the structure is not removed and the mesoporous structure does not appear. If the cleaning time is more than 24 hours, the structure may collapse.

In the step (d), the washed electrode is dried to obtain an electrode in which a manganese oxide thin film having an aligned mesoporous structure is formed. The manganese oxide electrode produced by the above manufacturing method has a large specific surface area and a stable mesoporous structure The effect of increasing the catalytic activity is exhibited.

The present invention as described above is specifically explained based on the following examples, and the present invention is not limited by the following examples.

Aligned Mesoporous Manganese Oxide Deposition Using SDS (Sodium Dodecyl Sulfate)

Step (a): 182.6 mg of MnNO ₃ powder and 251.08 mg of SDS are weighed into 100 ml of distilled water, placed in a beaker, and stirred for about 30 minutes to prepare an electrolyte.

Step (b): 5 ml of isopropanol and 5 ml of acetone are mixed with another beaker, and ITO glass is immersed and cleaned using an ultrasonic cleaner (JAC, JAC-2010) for about 30 minutes.

Step (c): silver-silver chloride electrode is used as a reference electrode, and washed ITO glass of the step (b) is used as a working electrode, and a counter electrode is used as a counter electrode. At this time, the working electrode and the counter electrode are configured so that the surfaces through which electricity can communicate face each other.

Step (d): The electrodes of step (c) are fully supported on the electrolyte of step (a) and electrostatically deposited at -1.6 V using a potentiostat (Bio-Logic SA, VSP) do.

Step (e): The electrode completed in step (d) is heat-treated at 200 ° C for 3 hours in an electric furnace (JISICO, J-FM38) to synthesize manganese oxide.

Step (f): The electrode completed in step (e) is immersed in 30 ml of ethanol for 18 hours and dried to complete the aligned mesoporous manganese oxide.

Aligned Mesoporous Manganese Oxide Deposition Using SDS (Sodium Dodecyl Sulfate) and Ethylene Glycol

Step (a): In Step (a) of Example 1, 28.06 mL of ethylene glycol was added to 71.94 mL of distilled water and the same procedure as in step (a) of Example 1 was conducted.

The mesoporous manganese oxides deposited in the same manner as in the above Examples (b) to (e) are deposited.

Aligned Mesoporous Manganese Oxide Deposition Using SDS (Sodium Dodecyl Sulfate) and CTAB (Cetrimonium Bromide)

Step (a): 25.8 mg of CTAB was added in step (a) of Example 1 and the same procedure as in step (a) of Example 1 was carried out.

The mesoporous manganese oxides deposited in the same manner as in the above Examples (b) to (e) are deposited.

≪ Comparative Example 1 & Deposition of manganese oxide without surfactant

Step (a): The step (a) of Example 1 is carried out in the same manner as the step (a) of Example 1 except for SDS.

Manganese oxides are deposited in the same manner as in the above examples (b) to (e).

≪ Comparative Example 2 & Manganese Oxide Deposition Using Sodium Dodecyl Sulfate (SDS) at Room Temperature

The electrolytes are prepared in the same manner as in the above Examples (a) to (c).

Step (d): In step (d) of the first embodiment, the deposition is performed at room temperature and the same procedure as in step (d) of the first embodiment is performed.

Manganese oxides are deposited in the same manner as in the above Examples (e) to (f).

≪ Comparative Example 3 & Manganese Oxide Deposition Using SDS (Sodium Dodecyl Sulfate) at 80 Degree

The electrolytes are prepared in the same manner as in the above Examples (a) to (c).

Step (d): In the step (d) of Example 1, the deposition is performed at a temperature of 80 ° C. in the same manner as in the step (d) of Embodiment 1.

Manganese oxides are deposited in the same manner as in the above Examples (e) to (f).

However, the amount of electrolyte was decreased by evaporation of electrolyte water during deposition, and consequently, the concentration of the precursor and surfactant in the electrolyte changed, and deposition under a constant condition was impossible.

≪ Comparative Example 4 & Synthesis of Manganese Oxide Using SDS (Sodium Dodecyl Sulfate) and Hydrothermal Synthesis at 70 ° C

Step (a): 474 mg of MnSO ₄ powder and 120 mg of SDS are weighed into 60 ml of distilled water, placed in a beaker, and stirred at 50 ° C. for one day to prepare a solution.

Step (b): The prepared solution is placed in an autoclave and reacted at 180 degrees for about 4 hours.

Step (c): The precipitate produced in the above process was filtered and then washed with a centrifuge to obtain manganese oxide. However, no precipitate was formed due to a low reaction temperature.

<Experimental Example 1> Electron microscopic observation of manganese oxide

Manganese oxides prepared by transmission electron microscope (JEOL, JEM-2100F) were observed to observe the structure of the manganese oxide produced by the examples 1, 2, and 3 and the comparative examples 1 and 2, , 3, 4 and 5, respectively.

FIGS. 1 and 4 are photographs of the aligned mesoporous manganese oxide deposited in Example 1 and Comparative Example 1, respectively, by transmission electron microscopy (TEM). According to FIG. 4, the manganese oxide deposited in the state where the surfactant and the additive are not present in Comparative Example 1 does not show a porous structure. On the other hand, it can be seen that the manganese oxide deposited in Example 1 has an aligned mesoporous structure corresponding to 3.47 nm. From FIGS. 2 and 3, it was observed that an ordered mesoporous structure appeared even when the additives were introduced. From FIG. 5, it was observed that the mesoporous structure was not formed even though the surfactant was contained when the film was deposited at room temperature.

<Experimental Example 2> X-ray diffraction analysis

The characteristics of the manganese oxides prepared by Examples 1, 2 and 3 and Comparative Examples 1 and 2 were analyzed by an X-ray diffractometer (Rigaku, Mini flex), and the results are shown in FIGS. 6, 7, 8 and 9 And 10, respectively.

FIGS. 6 and 9 show X-ray diffraction patterns (XRD) at low angles of the aligned mesoporous manganese oxide deposited in Example 1 and Comparative Example 1, respectively. According to FIG. 9, in the case of the manganese oxide electroplated in the state in which no surfactant is added in Comparative Example 1, no peaks appear at a low angle. On the other hand, the manganese oxide deposited in the electrolyte containing SDS in Example 1 exhibits several peaks at lower angles, indicating that there is an ordered mesoporous structure.

FIGS. 7 and 8 also show the X-ray diffraction pattern (XRD) at low angles of the manganese oxides prepared from Example 2 and Example 3. The manganese oxide produced in each example has a different peak, , Which means that each embodiment has a different structure.

<Experimental Example 3> Analysis of constituents of manganese oxide

The composition of the manganese oxide prepared in Example 1 was analyzed using an X-ray photoelectron spectroscopy (SPECS, EA200). The results are shown in Fig. As shown in FIG. 11, the peak of the Mn 3s binding energy of the manganese oxide of Example 1 according to the present invention exhibits a distance of 6.1 eV, indicating that the chemical bonding state of the thin film is MnO. This is consistent with the results of photoelectron spectroscopic analysis of manganese oxides in the literature (J. L. Junta, M. F. Hochella Jr., Geochimca et Cosmochimica Acta, 58 (1994) 4985-4999.)

<Experimental Example 4> Electrochemical behavior analysis by cyclic voltammetry

In order to comparatively analyze the performance of the manganese oxide produced by the above Examples 1, 2 and 3 as the electrode catalyst, the manganese oxide of the non-pore structure prepared in Comparative Example 1 and the manganese oxide prepared by Examples 1, 2 and 3 The following experiment was conducted using manganese oxide having a mesoporous structure.

To investigate the electrochemical properties of the manganese oxides prepared in Examples 1, 2 and 3 and Comparative Example 1, 0.5 mol of Na ₂ SO ₄ electrolytic solution was measured using a potentiostat (Princeton Applied Research, VSP) The cyclic voltammetry method was analyzed at a scanning speed of 50 mV / s. The results are shown in Fig.

Referring to FIG. 12, the manganese oxide of Example 3 of the present invention exhibits the highest current density per unit area. When used as an electrode material of an electrochemical device such as a supercapacitor, the manganese oxide has a higher It has electric storage capacity and fast charging / discharging speed. In addition, in the case of Example 1 in which only SDS was added and Example 2 in which ethylene glycol was added, although the synthesized mesopore structure was not stable, the current density per unit area was lower than that in Example 3, The current density was higher than that of the non-pore structure manganese oxide of Comparative Example 1 due to the existence of pores. Therefore, it can be seen that the manganese oxide of the mesoporous structure prepared in the present invention has better performance than the conventional electrode material as the electrode material of the electrochemical device.

EXPERIMENTAL EXAMPLE 5 Evaluation of Capacitance by Analysis of Discharge Curve

In order to evaluate the electric capacity of the ultra-high-capacity capacitor of manganese oxide prepared in Examples 1, 2 and 3, the manganese oxide of the non-pore structure prepared in Comparative Example 1 and the manganese oxide prepared in Examples 1, 2 and 3 The following experiment was conducted using manganese oxide having a mesoporous structure.

Discharge characteristics of the manganese oxide prepared in Examples 1, 2 and 3 and Comparative Example 1 were analyzed using a potentiostat in a Na ₂ SO ₄ electrolytic solution. The discharge capacity was measured by applying a constant current of 1 A / g. The results are shown in FIG.

Referring to FIG. 13, the manganese oxides of the mesoporous structure of Examples 1, 2, and 3 have discharge times of about 32 s, 35 s, and 35 s, respectively, and about twice the electric capacity of 16 s of Comparative Example 1 .

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereto will be. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (7)

In the method for producing manganese oxide,
(a) preparing an electrolyte by dissolving a manganese precursor, sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonium bromide (CTAB) in distilled water;
(b) electrodeposition the manganese hydroxide by applying a voltage in the range of -1.0 to -1.8 V in the temperature range of 65 to 75 ° C using the electrode system including the working electrode and the counter electrode to the electrolyte prepared in the step (a) step;
(c) heat treating the working electrode deposited with manganese hydroxide in the step (b) to obtain a working electrode coated with manganese oxide;
(d) washing and removing impurities remaining in the working electrode obtained in the step (c); And
(e) drying the working electrode obtained in step (d). &lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein the nitric acid precursor in step (a) is manganese nitrate (Mn (NO ₃ ) ₂ ) and the manganese nitrate (Mn (NO ₃ ) ₂ ) is in a concentration range of 0.005 to 0.05 M. &Lt; / RTI &gt; The method according to claim 1,
Wherein the sodium dodecyl sulfate in step (a) is added in an amount in the range of 0.5 to 3 wt%, and the cetyltrimethylammonium bromide (CTAB) is added in an amount in the range of 0.005 to 0.3 wt%. &Lt; / RTI &gt; delete The method according to claim 1,
The method of producing an manganese oxide having an ordered mesoporous structure according to claim 1, wherein the step (a) further comprises adding ethylene glycol to produce an electrolyte, and ethylene glycol is added to the distilled water in an amount of 30% by weight or less. The method according to claim 1,
Wherein the heat treatment in step (c) is performed at a temperature of 200 to 500 ° C for 3 hours or more. delete

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