KR101753662B1 - Oxygen evolution reaction catalyst comprising Ni-doped carbon nitride and preparation methods of the same - Google Patents

Abstract

The present invention relates to an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) and a production method thereof, and more particularly to a nickel precursor, a carbon nitride (C ₃ N ₄ ) precursor And mixing the solvent and then vaporizing the solvent to prepare a mixed powder (step 1); And a step (step 2) of heating the mixed powder of step 1 in a nitrogen atmosphere to prepare an oxygen generating reaction catalyst containing nickel-doped carbon nitride (Ni-C ₃ N ₄ ) (step 2), wherein the nickel precursor (Ni-C ₃ N ₄ ) doped with nickel is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride precursor.

Description

TECHNICAL FIELD The present invention relates to an oxygen generating reaction catalyst comprising nickel-doped carbon nitride and a method for producing the same.

The present invention relates to an oxygen-generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) and a method for producing the same.

There is growing interest in fuel cells to address sustainable green energy sources by addressing global warming and replacing the use of fossil fuels. Catalysts based on platinum (Pt) have been used to promote oxygen reduction reactions in the field of fuel cells. However, it is difficult to commercialize the platinum as a catalyst for the oxygen reduction reaction because of the disadvantage that the amount of the platinum is limited and the cost is very high and the activity is deteriorated due to impurities over time when it is used in a fuel cell.

Therefore, in order to solve the above-mentioned problems, researches have been conducted on a catalyst of a non-platinum oxygen reduction reaction in which the amount of platinum used in the electrode is reduced or platinum is not used as a catalyst for the oxygen reduction reaction. Among them, studies on carbon materials such as graphite are being conducted as catalysts for oxygen reduction reaction which does not use platinum at all.

For example, nitrogen-doped carbon nanotubes and nitrogen-doped porous graphites have been studied as carbon materials doped with a large amount of nitrogen as a catalyst for oxygen reduction reaction. These materials exhibit excellent performance as an electrochemical catalyst, have excellent durability, are environmentally friendly, and have a merit that they are much cheaper than platinum-based oxygen reduction catalysts.

On the other hand, attention has been paid to carbon nitride (C ₃ N ₄ ) as a carbon material containing nitrogen which can be used as a catalyst of a fuel cell. The carbon nitride (C ₃ N ₄ ) is a material having a structure in which hexagonal rings are arranged two-dimensionally with carbon and nitrogen alternately arranged. In theory, it is known as a material having a higher strength than diamond. Has been studied from many researchers. In this process, it has been found that organic compounds containing a large amount of nitrogen exhibit properties such as good oxidative power and high thermal stability. In recent years, carbon nitride (C ₃ N ₄ ) has been widely used not only in various parts requiring wear resistance, It has been reported that the application range of the conversion bandgap semiconductor material and the like can be very wide and it is also being studied as a catalyst for a fuel cell.

Korean Patent Laid-Open No. 10-2009-7000330 discloses a method for producing carbon nitride (gC ₃ N ₄ ). More specifically, it discloses a method for producing carbon nitride (gC ₃ N ₄ ) at a pressure of 10 ^-1 to 10 ^-9 mmHg (GC ₃ N ₄ ) having a molar ratio of carbon to nitrogen of 3: 4 by pyrolysis of non-metallic rhodium at a temperature gradient between room temperature and normal temperature. However, this method has to be carried out in a state close to a nearly vacuum state, and there is a problem that the catalytic activity is exhibited but the efficiency is low.

In recent years, methods for forming a complex with carbon nitride (C ₃ N ₄ ) have been researched. Among them, graphitic Carbon Nitride (gC ₃ N ₄ ) has a very stable three-dimensional structure with sp2 CN bond layered structure. This graphitic carbon nitride (gC ₃ N ₄ ) has a low band gap (2.7 eV), high thermal stability (about 600 ° C)

In particular, graphitic carbon nitride (gC ₃ N ₄ ) can act as an efficient mold for depositing nano-sized metal oxides due to its high specific surface area, excellent electrical conductivity and physical and chemical stability. There is unlimited application possibility in energy storage materials of device (lithium ion secondary battery, hydrogen storage fuel cell, super capacitor), gas sensor, fine parts for medical engineering, and high performance complex. Accordingly, research for producing graphitic nitriding carbon (gC ₃ N ₄ ) and studies for increasing the catalytic activity efficiency are underway.

Korean Patent Publication No. 10-2013-0134797 discloses a method for producing a carbon nitride (C ₃ N ₄ ) -graffin composite and a carbon nitride (C ₃ N ₄ ) -graffin composite produced thereby Specifically, the step of peeling the graphite oxide under a solvent to prepare a graphene oxide dispersion solution (step 1); It describes a graphene composite manufacturing method - cyan amide and carbon nitride was added to (cyanamide), comprising the step (step 2) to reflux at _{100 ~ 150 ℃ (C 3 N} 4) in the dispersion solution.

Korean Patent Publication No. 10-2012-0028457 discloses a method for producing a cathode catalyst for a polymer electrolyte fuel cell comprising carbon nitride (C ₃ N ₄ ) and a conductive carbon support, a catalyst for a polymer fuel cell, an electrode for a polymer fuel cell, (GC ₃ N ₄ ) dispersed on the surface thereof, and a catalyst prepared by the method. The present invention also relates to a method for producing a catalyst comprising a conductive carbon support formed by dispersing graphitic nitriding carbon (gC ₃ N ₄ ) on a surface thereof.

However, the Photography tick carbon nitride (gC ₃ N ₄₎ is a conventional carbon nitride (gC ₃ N ₄₎ than the actual circumstances that require smaller the degree exhibits a high catalytic efficiency, higher catalytic efficiency than to replace platinum and commercialization to be.

On the other hand, in the normal operation region of the fuel cell, the catalyst of the fuel cell is reduced in catalyst effective surface area due to Ostwald-ripening and migration due to dissolution-redeposition, . In order to solve such a problem, studies for improving the durability of the catalyst and the electrode have been actively carried out. One of the solutions is the application of the Oxygen Evolution Reaction (OER) active material. Oxygen Generating Reaction (OER) Catalyst is a catalyst that generates oxygen by decomposing water. When an oxygen generating reaction (OER) catalyst is present in a fuel cell electrode, the catalyst is corroded due to the high potential atmosphere in starting and stopping the fuel cell Catalytic corrosion can be prevented by first dissolving all water.

Conventional oxygen generating reaction (OER) active materials include Ru, RuO _2, and IrO _{2. Of} these, ruthenium (Ru), which is the most widely known oxygen generating reaction (OER), is vulnerable to acidic atmosphere And there is a problem of high cost.

Accordingly, the present inventors have found that an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) as an oxygen generating reaction (OER) And completed the present invention.

Korean Patent Publication No. 10-2009-7000330 Korean Patent Publication No. 10-2013-0134797 Korean Patent Publication No. 10-2012-0028457

It is an object of the present invention to provide an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) and a method for producing the same.

In order to achieve the above object,

Wherein the nickel precursor is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride precursor, and the nickel precursor is produced by adding nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

In addition,

Mixing a nickel precursor, a carbon nitride (C ₃ N ₄ ) precursor and a solvent, and then vaporizing the solvent to prepare a mixed powder (Step 1); And

(Step 2) of preparing an oxygen-generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) by heating the mixed powder of step 1 in a nitrogen atmosphere,

Wherein the nickel precursor is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride precursor, wherein the nickel precursor is nickel-doped carbonitride (Ni-C ₃ N ₄ ) .

Further,

And an oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

Further,

And an oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

The oxygen generating reaction catalyst comprising nickel-doped carbon nanotubes (Ni-C ₃ N ₄ ) of the present invention is an oxygen generating reaction catalyst which is lower in cost and significantly improved in efficiency than the conventional oxygen generating reaction catalyst, There is an advantage that it can be applied to.

In addition, a method of producing an oxygen-generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) may be a nickel-doped carbonitride (Ni-C ₃ N ₄ ) An oxygen-generating reaction catalyst can be produced.

1 and 2 are scanning electron microscope (SEM) photographs showing the shape of nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced according to an embodiment of the present invention,
FIG. 3 is a transmission electron microscope (TEM) photograph showing the shape of nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced according to an embodiment of the present invention,
FIG. 4 is a graph showing phase analysis of carbon nitride (Ni-C ₃ N ₄ ) produced by Examples and Comparative Examples of the present invention using an X-ray diffractometer (XRD)
FIG. 5 is a graph showing a result of phase analysis of carbon nitride (Ni-C ₃ N ₄ ) produced by Examples and Comparative Examples of the present invention using an FT-IR analyzer,
FIG. 6 is a graph showing a result of thermogravimetry analysis (TGA) performed on nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced according to an embodiment of the present invention,
FIG. 7 is a graph showing the results of measurement of oxygen generating reaction (OER) activity of carbon nitride (Ni-C ₃ N ₄ ) produced by Examples and Comparative Examples of the present invention.

The present invention

Wherein the nickel precursor is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride precursor, and the nickel precursor is produced by adding nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

Oxygen Generating Reaction (OER) Catalyst is a catalyst that generates oxygen by decomposing water. When an oxygen generating reaction (OER) catalyst is present in a fuel cell electrode, the catalyst is corroded due to a high potential atmosphere in starting and stopping the fuel cell Catalytic corrosion can be prevented by first dissolving all water.

Conventional oxygen generating reaction (OER) active materials include Ru, RuO _2, and IrO ₂ . Among them, ruthenium (Ru), which is the most widely known oxygen generating reaction (OER) material, is expensive and is also vulnerable to acidic atmosphere, which is a fuel cell condition.

On the other hand, the oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) of the present invention can be produced at a low cost and has an advantage of excellent activity in the oxygen generating reaction.

The nickel-doped carbon nitride (Ni-C ₃ N ₄ ) may be prepared by heating a nickel precursor and a carbon nitride (C ₃ N ₄ ) precursor together. That is, there are a considerable number of nitrogen atoms in carbon nitride (C ₃ N ₄ ). In the nitrogen, there are five outermost electrons, three of which participate in bonding but two of which are present in a lone pair When the nickel precursor and the carbon nitride (C ₃ N ₄ ) precursor are heated together, a lone pair of nitrogen bonds with the nickel element to form nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

Preferably, the nickel precursor is a halogenated nickel compound comprising nickel chloride (II) hydrate (NiCl ₂ .6H ₂ O), and the carbon nitride (C ₃ N ₄ ) precursor is urea, melamine (2- amino-4,6-dichlorotriazine, cyanuric chloride, calcium cyanamide, sodium amide, 2,5,8-triamino-tri-striazine, cyanamide cyanamide, dicyandiamide (DCDA), and a compound of these compounds is preferably used.

In this case, the nickel precursor is preferably contained in an amount of 0.05 to 0.2% by mass relative to the mass of the carbon nitride precursor.

This is to increase the catalytic activity of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ). If the nickel precursor is contained in an amount of less than 5 mass% based on the mass of the carbon nitride precursor If the nickel precursor is contained in an amount of more than 20% by mass based on the mass of the carbon nitride precursor, the activity of the oxygen generating reaction catalyst may be lowered 20 mass%, while the nickel precursors are agglomerated and oxidized during the manufacturing process, thereby increasing the amount of the catalyst that is not used. That is, the amount of the catalyst to be used as the amount of the catalyst is reduced, resulting in an economical efficiency deterioration.

The oxygen generating reaction catalyst containing the nickel-doped carbon nanotubes (Ni-C ₃ N ₄ ) of the present invention can be produced at a low cost, and instead of expensive catalyst materials such as Ru, RuO ₂ and IrO ₂ And can be used as an oxygen generating reaction catalyst for a fuel cell.

Further, the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) has a porous and layered structure and has an overvoltage lower than that of conventional graphitic nitriding carbon (gC ₃ N ₄ ) The present invention has the advantage of being able to manufacture a fuel cell having excellent stability and performance at a low cost when the oxygen generating reaction catalyst is used for a fuel cell.

In addition,

Mixing a nickel precursor, a carbon nitride (C ₃ N ₄ ) precursor and a solvent, and then vaporizing the solvent to prepare a mixed powder (Step 1); And

(Step 2) of preparing an oxygen-generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) by heating the mixed powder of step 1 in a nitrogen atmosphere,

Wherein the nickel precursor is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride precursor, wherein the nickel precursor is nickel-doped carbonitride (Ni-C ₃ N ₄ ) .

Hereinafter, a method for producing an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) according to the present invention will be described in detail.

In the method for producing an oxygen generating reaction catalyst comprising nickel-doped carbon nanotubes (Ni-C ₃ N ₄ ) according to the present invention, step 1 is a step in which a nickel precursor, a carbon nitride (C ₃ N ₄ ) Mixing the solvent, and then vaporizing the solvent to prepare a mixed powder.

The step 1 is for preparing a mixed powder in which the nickel precursor and the carbon nitride precursor material are mixed by thoroughly mixing the nickel precursor, the carbon nitride (C ₃ N ₄ ) precursor, and the solvent, followed by vaporizing the solvent.

At this time, it is preferable that the nickel precursor is contained in an amount of 5 to 20 mass% with respect to the mass of the carbon nitride precursor.

This is to increase the catalytic activity of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by the above production method. If the nickel precursor has a mass of 5 mass %, There may arise a problem that oxygen generating reaction does not occur due to insufficient oxygen generating reaction catalytic action, and when the nickel precursor is contained in an amount exceeding 20 mass% with respect to the mass of the carbon nitride precursor, The activity of the reaction catalyst is similar to that in the case of containing 20 mass% of the catalyst, whereas the nickel precursors are agglomerated and oxidized during the manufacturing process, thereby increasing the unused content of the catalyst. That is, the amount of the catalyst to be used as the amount of the catalyst is reduced, resulting in an economical efficiency deterioration.

The nickel precursor is preferably a halogenated nickel compound including nickel chloride (II) hydrate (NiCl ₂ .6H ₂ O), and the carbon nitride (C ₃ N ₄ ) precursor is urea, melamine 2-amino-4,6-dichlorotriazine, cyanuric chloride, calcium cyanamide, sodium amide, 2,5,8-triamino-tri-striazine, It is preferable to use one species selected from the group consisting of cyanamide, dicyandiamide (DCDA), and compounds thereof.

The solvent may be one selected from the group consisting of ethanol, acetone, and water, but is not limited thereto. The solvent may dissolve the nickel precursor and the carbon nitride (C ₃ N ₄ ) precursor, Any solvent can be used as long as it can dry-remove the solvent.

The solvent may be vaporized by heating at a temperature of 60 to 150 ° C, but the present invention is not limited thereto. The solvent may be added at a proper rate without oxidizing the nickel precursor and the carbon nitride (C ₃ N ₄ ) Other suitable methods that can be vaporized may be used.

In the method for producing an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) according to the present invention, step 2 is a step of heating the mixed powder of step 1 in a nitrogen atmosphere to prepare nickel- Generating catalyst comprising carbon nitride (Ni-C ₃ N ₄ ).

The step 2 is for forming nickel-doped carbon nitride (Ni-C ₃ N ₄ ) powder by the condensation reaction of the mixed powder.

For this, the heating in step 2 is preferably performed at 500 to 600 ° C. If the heating is carried out at a temperature lower than 500 ° C., a process of forming melamine, which is a basic unit of carbon nitride, is shown, but nitrogen-rich carbon nitride having a highly ordered structure by a stepwise condensation reaction A problem may arise that the carbon nitride structure is collapsed and the ratio of nitrogen is remarkably lowered when it is carried out at a temperature exceeding 600 ° C.

Meanwhile, it is preferable that the heating in the step 2 is performed in a nitrogen atmosphere. For example, the heating may be performed by a method in which a mixed powder is put into a tube furnace, which is a heat treatment equipment, .

Through the heating, a lone pair of nitrogen bonds with the nickel element to form nickel-doped carbon nitride (Ni-C ₃ N ₄ ). That is, there are a considerable number of nitrogen atoms in carbon nitride (C ₃ N ₄ ). In the nitrogen, there are five outermost electrons, three of which participate in bonding but two of which are present in a lone pair When the nickel precursor and the carbon nitride (C ₃ N ₄ ) precursor are heated together, the lone pair of nitrogen bonds with the nickel element to form nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

The method for producing an oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) of the present invention is characterized in that the nickel-doped carbon nitride (Ni-C ₃ N ₄ ). ≪ / RTI >

The product formed after step 2 may include an unreacted precursor and a solvent as an impurity other than the oxygen generating reaction catalyst containing nickel-doped carbon nitride (Ni-C ₃ N ₄ ), and the nickel- Only the oxygen generating reaction catalyst containing carbon nitride (Ni-C ₃ N ₄ ) is recovered.

At this time, the recovery may be performed by slowly cooling the product of step 2 to room temperature, followed by filtration, washing and drying.

For example, the recovery may be performed by filtering the product by a conventional filtration method used in the art, washing it with ethanol, preliminarily drying it in the air, and finally drying it under vacuum conditions.

However, the recovery method is not limited thereto, and it is possible to use other suitable methods capable of separating the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) from other impurities without being denatured and oxidized ≪ / RTI > method.

Further,

And an oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

The electrode for a fuel cell including the oxygen generating reaction catalyst containing the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) includes a catalyst having excellent oxygen generating reaction activity, so that the durability of the electrode for a fuel cell can be further improved have.

Oxygen Generating Reaction (OER) Catalyst is a catalyst that generates oxygen by decomposing water. When an oxygen generating reaction (OER) catalyst is present in a fuel cell electrode, the catalyst is corroded due to the high potential atmosphere in starting and stopping the fuel cell It is possible to prevent the corrosion of the redox reaction catalyst by first decomposing all the water, and it is possible to prevent the problem that the catalyst performance is deteriorated.

That is, the redox reaction catalyst of the conventional fuel cell has a problem that the effective surface area of the catalyst is reduced due to the owato-ripening and the migration due to dissolution-redeposition, Respectively. In order to solve such problems, researches on improvement of durability of catalysts and electrodes have been progressing actively. One of the solutions thereof is the application of Oxygen Evolution Reaction (OER) active material, The problem of degradation of the performance of the catalyst can be prevented and the durability of the fuel cell can be further improved.

In addition, there is an advantage that the conventional Ru, RuO _2, and IrO ₂ can be manufactured at lower cost than an electrode for a fuel cell including an oxygen generating reaction catalyst.

Further,

And an oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ).

The fuel cell includes a catalyst having excellent oxygen generating reaction activity, thereby being a fuel cell having improved durability.

In addition, there is an advantage that conventional Ru, RuO _2, and IrO ₂ can be manufactured at a lower cost than a fuel cell including an oxygen generating reaction catalyst.

Hereinafter, the present invention will be described in detail with reference to Examples, Comparative Examples and Experimental Examples.

However, the following Examples, Comparative Examples and Experimental Examples are merely illustrative of the present invention, and the present invention is not limited to the following Examples.

≪ Example 1 >

An oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) was prepared through the following steps.

Step 1: 50 mg of NiCl ₂ , 1 g of melamine and 10 ml of ethanol were mixed at a temperature of 80 ° C, and ethanol was vaporized to prepare a mixed powder containing 5% of NiCl ₂ relative to melamine.

Step 2: The mixed powder of step 1 was placed in a furnace and heated at 520 ° C for about 4 hours to prepare an oxygen generating reaction catalyst containing nickel-doped carbon nitride (Ni-C ₃ N ₄ ) . At this time, the heating was performed at a rate of 10 ° C / min and a nitrogen atmosphere.

≪ Example 2 >

The procedure of Example 1 was repeated except that the NiCl ₂ content in Step 1 was changed to 70 mg to prepare a mixed powder containing 7% of NiCl ₂ relative to melamine. Thus, a nickel-doped nitrided An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

≪ Example 3 >

The procedure of Example 1 was repeated except that the NiCl ₂ content in Step 1 was changed to 100 mg to prepare a mixed powder containing 10% of NiCl ₂ relative to melamine, thereby obtaining a nickel-doped nitride An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

<Example 4>

The procedure of Example 1 was repeated except that 200 mg of NiCl _{2 in} Step 1 was changed to 20% of NiCl ₂ relative to melamine to prepare a nickel-doped nitride An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

&Lt; Comparative Example 1 &

The oxygen generating reaction catalyst comprising graphitic carbon nitride (gC ₃ N ₄ ) was prepared in the same manner as in Example 1 except that NiCl ₂ was not contained in the step 1 in Example 1 Respectively.

&Lt; Comparative Example 2 &

The procedure of Example 1 was repeated except that the NiCl ₂ content in Step 1 was changed to 10 mg to prepare a mixed powder containing 1% of NiCl ₂ relative to melamine. Thus, nickel-doped nitrided An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

&Lt; Comparative Example 3 &

The procedure of Example 1 was repeated to prepare a mixed powder containing 3% of NiCl ₂ relative to melamine by changing the content of NiCl ₂ in the above step 1 to 30 mg to prepare a nickel-doped nitride An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

&Lt; Comparative Example 4 &

The procedure of Example 1 was repeated except that the NiCl ₂ content of the step 1 was changed to 300 mg to prepare a mixed powder containing 30% of NiCl ₂ relative to melamine. Thus, nickel-doped nitrided An oxygen generating reaction catalyst containing carbon (Ni-C ₃ N ₄ ) was prepared.

<Experimental Example 1> Scanning Electron Microscope (SEM) Analysis

The following experiment was conducted to confirm the shape of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention.

The microstructure was observed using a scanning electron microscope (SEM) on the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared in Examples 1 and 3, 1 and Fig.

As shown in Figs. 1 and 2, all of the oxygen generating reaction catalysts comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Examples 1 and 3 have a layered structure, i.e., It can be seen that it has a carbon nitride (gC ₃ N ₄ ) structure.

Accordingly, the oxygen generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) of the present invention has a low band gap, high thermal stability, and high catalytic activity due to the graphitic carbon nitride (gC ₃ N ₄ ) It can be expected to have an activity.

<Experimental Example 2> Transmission electron microscope (TEM) analysis

The following experiment was conducted to confirm the shape of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention.

The microstructure of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared in Example 3 was observed using a transmission electron microscope (TEM) Respectively.

As shown in FIG. 3, the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Example 3 has a porous structure.

Accordingly, it is expected that the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) according to the present invention has excellent catalytic activity due to the porous structure.

Experimental Example 3 X-ray photoelectron spectroscopy (XPS) analysis

The following experiment was conducted to confirm the proportion of the components of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention.

X-ray photoelectron spectroscopy (XPS) was applied to the oxygen generating reaction catalyst containing carbon nitride (C ₃ N ₄ ) prepared in Examples 1 to 4 and Comparative Examples 1 to 3 The results are shown in Table 1 below.

C
(atom%) N
(atom%) O
(atom%) Ni
(atom%) Cl
(atom%) C / N
(atom%) C / O
(atom%) Comparative Example 1 49.40 45.99 4.61 0 0 1.07 10.71 Comparative Example 2 47.71 43.22 7.27 0.15 0 1.10 6.56 Comparative Example 3 48.66 47.42 3.72 0.21 0 1.03 13.08 Example 1 45.18 49.4 4.4 0.52 0 0.91 10.27 Example 2 47.15 46.56 4.44 1.85 0 1.10 10.62 Example 3 43.10 48.88 4.69 2.30 0 0.88 9.19 Example 4 45.56 46.18 3.25 2.36 0 0.99 14.02 Comparative Example 4 48.14 43.43 2.93 2.74 0 1.11 13.08

As shown in Table 1, in the case of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Examples 1 to 4 and Comparative Examples 1 to 3, The content of nickel doped in carbon nitride (Ni-C ₃ N ₄ ) gradually increases as the content of NiCl ₂ increases.

Thereby, the oxygen generating reaction catalyst which nickel comprises the doped carbon nitride (Ni-C ₃ N ₄₎ of the present invention is doped with the content of is used in the manufacture of nickel precursor to carbon nitride (Ni-C ₃ N ₄₎ It is understood that the content of nickel is controlled.

<Experimental Example 4> X-ray diffractometer (XRD) phase analysis

In order to compare the phases of the oxygen generating reaction catalyst and the graphitic carbon nitride (gC ₃ N ₄ ) containing nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention, Experiments were performed.

Phase analysis was performed on the carbon nitride (C ₃ N ₄ ) produced by Examples 1 to 3 and Comparative Examples 1 to 3 using an X-ray diffraction (XRD) Is shown in Fig.

As shown in FIG. 4, the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Examples 1 to 3, Comparative Example 2 and Comparative Example 3 had a graphitic carbon nitride (gC &lt; ₃ &gt; N &lt; ₄ &gt;). That is, that the phase change of nickel on carbon nitride (C ₃ N ₄₎ (Ni) is due to the included may be seen that not, through them, the nickel (Ni) is doped in the carbon nitride (C ₃ N ₄₎ can see.

<Experimental Example 5> FT-IR analysis

In order to compare the phases of the oxygen generating reaction catalyst and the graphitic carbon nitride (gC ₃ N ₄ ) containing nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention, Experiments were performed.

Phase analysis was performed on the carbon nitride (C ₃ N ₄ ) produced by Examples 1 to 3 and Comparative Examples 1 to 3 using an FT-IR analyzer, and the results are shown in FIG.

As shown in FIG. 5, the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Examples 1 to 3, Comparative Example 2 and Comparative Example 3 had a graphitic carbon nitride (gC &lt; ₃ &gt; N &lt; ₄ &gt;). That is, a nitrogen (C ₃ N ₄₎ in the nickel (Ni) is a phase change caused by incorporated can be seen that no, through which, the nickel (Ni) The carbon nitride as the results obtained in Experimental Example 4 (C ₃ N ₄ ). &Lt; / RTI &gt;

<Experimental Example 6> Thermogravimetric analysis (TGA) analysis

The following experiment was conducted to confirm the thermal stability of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention.

Thermogravimetry analysis (TGA) experiments were performed on the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared in Examples 1 to 3, and the results are shown in FIG.

As shown in Fig. 6, all of the nickel-doped carbon niobium carbide (Ni-C ₃ N ₄ ) produced by Examples 1 to 3 had no mass change at 550 캜 or lower, and the mass rapidly increased between 550 캜 and 700 캜 As shown in FIG. Accordingly, the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by the production method of the present invention can be expected to have excellent thermal stability.

<Experimental Example 7> Oxygen generating reaction (OER) catalytic activity analysis

The following experiments were conducted to confirm the oxygen evolution reaction (OER) activity of the oxygen generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) prepared according to the present invention .

Catalyst electrode manufacturing

Each of the oxygen generating reaction catalysts containing the carbon nitride (gC ₃ N ₄ ) prepared in Examples 1 to 4 and Comparative Examples 1 to 4 was dissolved in a solvent containing 00.99 ml of ethanol, 0.99 ml of water and 20 μl of Nafion To prepare a catalyst solution.

The catalyst solution was loaded twice onto the working electrode in 5 μL increments to yield 79.58 μg / cm ² And dried to form catalyst electrodes for each of them. The working electrode used was a rotation disk electrode (RDE electrode) of 3 mm glassy carbon.

Oxygen evolution reaction (oxygen evolution reaction, OER ) Evaluation of activity

The electrode was immersed in a 1 molar potassium hydroxide (KOH) electrolyte solution together with the catalyst electrode, a reference electrode of a mercury surface electrode (MSE) and a counter electrode of a platinum wire (Pt wire) The current-potential value was measured by scanning from 1.2 V to 1.8 V at a speed of 5 mV / s and the results are shown in FIG. 7 and FIG. The onset potential values in the graph of FIG. 7 are shown in Table 2 below.

The activity of the oxygen generating reaction catalyst can be considered as the smaller the onset potential and the higher the current density, the better the efficiency.

The onset potential (V vs. RHE) Comparative Example 1 (g-C3N4) 1.68 Comparative Example 2 (NiCl ₂ -10 ml) 1.68 Comparative Example 3 (NiCl ₂ -30 ml) 1.65 Example 1 (NiCl ₂ -50 ml) 1.61 Example 2 (NiCl ₂ -70 ml) 1.60 Example 3 (NiCl ₂ -100 ml) 1.58 Example 4 (NiCl ₂ -200 ml) 1.54 Comparative Example 4 (NiCl ₂ -300 ml) 1.54

As shown in Table 2 and FIG. 7, it can be seen that the oxygen generation reaction catalyst containing carbon nitride (Ni-C ₃ N ₄ ) having a high nickel doping content has a lower onset potential value have. In addition, as shown in the tafel slope of FIG. 8, the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) produced by Examples 3 and 4 exhibited 88 mV / dec and 60 mV / dec shows a lower tafel slope than the graphitic nitriding carbon (gC ₃ N ₄ ) produced by Comparative Example 1, whereby the nickel prepared according to Examples 3 and 4 is doped (Ni-C ₃ N ₄ ) exhibited higher catalytic activity.

Claims (10)

(Ni-C ₃ N ₄ ), wherein the nickel precursor is contained in an amount of 5 to 20 mass% based on the mass of the carbon nitride (C ₃ N ₄ ) precursor. .
The oxygen-generating reaction catalyst according to claim 1, wherein the catalyst has a layered structure and a porosity, and comprises nickel-doped carbon nitride (Ni-C ₃ N ₄ ).
The method of claim 1, wherein the catalyst comprises a carbon nitride (Ni-C ₃ N ₄₎ of nickel is doped, it characterized in that the nickel has a layer structure of the Photography tick carbon nitride (Ni-gC ₃ N ₄₎ doped Oxygen generating reaction catalyst.
Mixing a nickel precursor, a carbon nitride (C ₃ N ₄ ) precursor and a solvent, and then vaporizing the solvent to prepare a mixed powder (Step 1); And
(Step 2) of preparing an oxygen-generating reaction catalyst comprising nickel-doped carbon nitride (Ni-C ₃ N ₄ ) by heating the mixed powder of step 1 in a nitrogen atmosphere,
Wherein the nickel precursor is contained in an amount of 5 to 20% by mass based on the mass of the carbon nitride precursor, and the nickel precursor is nickel-doped carbon nitride (Ni-C ₃ N ₄ ).
The method of claim 4, wherein the nickel precursor of step 1 is nickel chloride (II) hydrate (NiCl ₂ and 6H ₂ O) halogenated nickel compound, characterized in nickel nitride carbon (Ni-C ₃ doping comprises the compound N ₄ ). &Lt; / RTI &gt;
The method of claim 4, wherein the carbon nitride (C ₃ N ₄ ) precursor of step 1 is selected from the group consisting of urea, 2-amino-4,6-dichlorotriazine, cyanuric chloride, from the group consisting of calcium cyanamide, sodium amide, 2,5,8-triamino-tri-striazine, cyanamide, dicyandiamide (DCDA) (Ni-C ₃ N ₄ ) doped with nickel, characterized in that the nickel-doped carbon nitride (Ni-C ₃ N ₄ )
5. The oxygen-generating reaction catalyst according to claim 4, wherein the solvent of step 1 is one selected from the group consisting of ethanol, acetone, and water, and comprises nickel-doped carbon nitride (Ni-C ₃ N ₄ ) Gt;
5. The method according to claim 4, wherein the heating in step 2 is performed at 500 to 600 ° C. The method for producing an oxygen generating reaction catalyst according to claim 4, wherein the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) is nickel.
An electrode for a fuel cell comprising an oxygen-generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) of claim 1.
A fuel cell comprising an oxygen-generating reaction catalyst comprising the nickel-doped carbon nitride (Ni-C ₃ N ₄ ) of claim 1.

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