KR101781442B1 - Carbon catalyst comprising surfur and nitrogen with doped iron and preparing method thereof - Google Patents

Abstract

The present invention relates to an iron-doped nitrogen/sulfur-containing carbon catalyst, and a production method thereof. More specifically, provided is an iron-doped nitrogen/sulfur-containing carbon catalyst consisting of: an iron precursor; a spherical organic ligand framework surrounding the iron precursor; a graphene sheet coupled to the outside of the organic ligand framework; and a carbon nanofiber coupled to the outside of the organic ligand framework. According to the present invention, the iron-doped nitrogen/sulfur-containing carbon catalyst produced thereby can be used in an oxygen reduction reaction. Particularly, the iron-doped nitrogen/sulfur-containing carbon catalyst produced in the present invention exhibits outstanding oxygen reduction activities, long-term circulation stability, and methanol durability under alkali condition.

Description

TECHNICAL FIELD The present invention relates to a carbon catalyst containing iron-doped nitrogen and sulfur and to a process for preparing the same.

The present invention relates to a carbon catalyst comprising iron-doped nitrogen and sulfur and a process for preparing the same, and more particularly to a carbon catalyst comprising iron-doped nitrogen and sulfur, To a carbon catalyst comprising iron-doped nitrogen and sulfur and to a process for their preparation.

An oxygen reduction reaction (ORR) is a critical and critical process in renewable energy technologies such as fuel cells and metal-air cells. Commonly used catalysts in ORR are platinum (Pt), gold (Au), palladium (Pd) and their alloy nanoparticles. However, these catalysts are hampering practical applications due to limited resources, high cost, low stability, and high overpotential characteristics.

Therefore, transition metal-based materials such as oxides, nitrides, and chalcogenides are not only inexpensive, but also have a great interest because of their excellent ORR performance when compared to Pt catalysts. However, for practical application of transition metal- And catalyst properties, it is still not appropriate.

Carbon materials such as carbon nanotubes (CNTs) and graphene, which have high surface area, high crystallinity, and good conductivity, which are important and desirable factors for various applications, are considered.

(E.g., N, S, P, and B) to a carbon material such as CNTs and graphene by thermal decomposition of a mixture of various external sources, especially chemical vapor deposition When doped, these materials exhibited excellent catalytic activity, and in particular, the nitrogen-doped carbon material exhibited unique and excellent ORR characteristics originating in conjugation between graphene and a nitrogen lone electron pair.

The doping of these materials depends on the external nitrogen precursor. However, the external nitrogen precursor is still unstable for efficient doping. Therefore, there is a need to develop a method using precursors suitable as templates for porous carbon catalysts.

Metal-organic frameworks (MOFs) or coordination polymers have been proposed as suitable precursors for the template for porous carbon catalysts. MOFs and coordination polymers have received considerable interest in industry and academia because of their potential applications in a variety of fields such as gas storage, separation, sensing, drug delivery, and catalysis.

MOFs can be prepared by using an organic ligand (an atom having N, O, and S) and a metal ion. Due to the various metal ions and organic building blocks of MOFs, and the possibility of various surface morphologies, they are being used as suitable precursors for the preparation of carbon catalysts, and also for the production of porous carbon and metals for energy conversion and other applications Are used as precursors / templates to prepare oxides.

For example, zeolitic imidazolate framework (ZIF) and iron-based metal-organic structures derived from nitrogen-doped carbon, which have demonstrated electrocatalytic activity against ORR, organic frameworks were used to prepare graphite and controlled the size of the porous carbon for good oxygen reduction and high capacity.

Core-shell structured carbons were also prepared through seed-mediated growth of ZIF-8 and ZIF-67 for capacity studies. However, due to the lack of Heteroatom-rich MOFs with the desired shape, no studies have been reported on heterodimerized heteroatoms containing MOFs.

MOFs consisting mainly of nitrogen doped catalysts have been reported in several studies for binary heteroatom-doped catalysts using MOFs, but an example of preparing a carbon doped with a heteroatom from a combination of MOFs and a second external precursor none.

In addition, recent studies have reported improved ORR activity when doping carbon containing nitrogen with iron or cobalt, but even though nitrogen and iron / cobalt doped carbon catalysts have been extensively studied, low cost and high efficiency There is no example of evaluating the carbon catalyst activity including iron-doped nitrogen and sulfur with iron-doped nitrogen.

Therefore, it is urgent to research and develop a high-performance iron-doped carbon catalyst including nitrogen and sulfur using a unique precursor so as to be widely applicable to an oxidation-reduction catalyst, a battery, a super high capacity capacitor, and an electrode catalyst material.

Korean Patent Publication No. 2011-0138255

It is an object of the present invention to provide a process for the production of a catalyst having a low cost and high efficiency capable of replacing existing catalyst materials such as platinum, gold, palladium, and their alloy nanoparticles whose practical application is limited due to resource limitation, high cost, low stability, A carbon catalyst containing iron-doped nitrogen and sulfur, and a process for producing the same.

In order to accomplish the above object, the present invention provides an iron precursor; A spherical organic ligand skeleton formed to surround the iron precursor; A graphene sheet bonded to the outside of the organic ligand skeleton; And carbon nanofibers bonded to the outside of the organic ligand skeleton. The present invention also provides a carbon catalyst comprising iron-doped nitrogen and sulfur.

The present invention also provides a sensor comprising the carbon catalyst.

The present invention also relates to a process for preparing a zinc-organic ligand skeleton (hereinafter referred to as " zinc-organic ligand skeleton ") which is a polymer composed of a zinc precursor, an organic ligand containing nitrogen and sulfur and a polyvinylpyrrolidone, ; Mixing the zinc-organic ligand skeleton and the iron precursor with distilled water and stirring to synthesize an iron-doped skeleton; Carbonizing the iron-doped skeleton in a nitrogen atmosphere to synthesize a carbon catalyst containing iron-doped nitrogen and sulfur; And removing the zinc in the carbon catalyst to activate the carbon catalyst. The present invention also provides a method for preparing a carbon catalyst comprising iron-doped nitrogen and sulfur.

The iron-doped carbon and the sulfur-containing carbon catalyst according to the present invention can be used for the oxygen reduction reaction.

In particular, the iron-doped carbon and the sulfur-containing carbon catalysts according to the present invention exhibit a significant oxygen reduction activity with an initial potential and a half-wave potential of 0.026 V and -0.131 V, respectively.

Also, the carbon catalysts containing iron-doped nitrogen and sulfur exhibited a higher limiting current density (7.20 mA / cm ² ) than the commercial catalyst Pt / C (5.91 mA / cm ² ) .

Brief Description of the Drawings Fig. 1 is a schematic view showing a FESEM image of a small particle (b) and a large particle (c) of ZnDTO for synthesis of Fe-NSC for oxygen reduction reaction,
2 shows the SEM image (Aa) of Fe-NSC and the SEM image (Ab) after cleaning, 900 ° C (Ba), (Bb) 700 ° C, (Bc) 800 ° C, and (Bd) 5 is a view showing an FESEM image of Fe-NSC synthesized at 1000 ° C,
Figure 3 shows the XPS spectrum (a) deconvoluted for N1s of Fe-NSC, the Raman spectrum (b) for various Fe-NSC catalysts, the XRD pattern (c) for NSC and Fe- (D) for BSC surface area measurements for NSC,
Figure 4 shows the oxygen reduction CV curve for Fe-NSC in an electrolyte solution saturated with nitrogen at 0.1 M KOH and the oxygen reduction CV curve for Fe-NSC, NSC, and Pt / C in an electrolyte solution saturated with oxygen (b) a linear sweep voltammetry (LSV) curve (b) at a scan rate of 10 mV / s for Fe-NSC catalyst prepared at 700 ° C., 800 ° C., 900 ° C., (C), LSV curve (d) and KL diagram (e) for Fe-NSC with various rotational speeds at a scan rate of 10 mV / s for Fe-NSC, NSC and Pt / And graphs of kinetic current density (f) for Fe-NSC, NSC, and Pt / C catalysts,
Figure 5 shows the Tappel's diagram (a) for Fe-NSC, NSC and Pt / C catalysts, the RDE polarization curve (b) of Fe-NSC before and after 5000 cycles, Fe-NSC and Pt / C catalyst (c), and the time-current response (d) of Fe-NSC and Pt / C catalyst after addition of 3 M methanol at -0.2 V. FIG.

Hereinafter, the iron-doped carbon catalyst including nitrogen and sulfur according to the present invention and a method for producing the same will be described in more detail.

The inventors of the present invention have found that iron-doped carbon and nitrogen-containing carbon catalysts obtained by mixing an iron-based precursor with an organic ligand containing nitrogen and sulfur and performing a carbonization process exhibit an oxygen reduction activity superior to that of an iron- And it is also possible to produce catalysts which are more economical and more efficient than conventional catalyst materials such as platinum, gold, palladium and their alloy nanoparticles. Thus, the present invention has been completed.

The present invention relates to an iron precursor; A spherical organic ligand skeleton formed to surround the iron precursor; A graphene sheet bonded to the outside of the organic ligand skeleton; And carbon nanofibers bonded to the outside of the organic ligand skeleton. The present invention also provides a carbon catalyst comprising iron-doped nitrogen and sulfur.

Said iron precursors may be hemoglobin, ferrous sulfate (FeSO _4), ferric sulfate _{(Fe 2 (SO 4) 3} ), iron nitrate (Fe (NO _3)), and ferric chloride at least one selected from the group consisting of (FeCl ₃₎ But is not limited thereto.

The organic ligand skeleton is composed of a polymer composed of a zinc-dithiooxamide complex, a polymer composed of a zinc-thioacetamide complex, and a polymer composed of a zinc-thiocarbamide complex , But the present invention is not limited thereto.

The spherical organic ligand skeleton may be composed of spherical organic ligands having an average diameter of 850 to 950 nm and spherical organic ligands having an average diameter of 2900 to 3100 nm, but is not limited thereto.

The present invention also provides a sensor comprising the carbon catalyst.

The sensor may be any one of a dopamine detection sensor, an ascorbic acid detection sensor, a phenol detection sensor, a toxic substance detection sensor, a heavy metal detection sensor, a hydrogen peroxide detection sensor, a glucose detection sensor, an immune sensor, or an enzyme sensor no.

The present invention also relates to a process for preparing a zinc-organic ligand skeleton (hereinafter referred to as " zinc-organic ligand skeleton ") which is a polymer composed of a zinc precursor, an organic ligand containing nitrogen and sulfur and a polyvinylpyrrolidone, ; Mixing the zinc-organic ligand skeleton and the iron precursor with distilled water and stirring to synthesize an iron-doped skeleton; Carbonizing the iron-doped skeleton in a nitrogen atmosphere to synthesize a carbon catalyst containing iron-doped nitrogen and sulfur; And removing the zinc in the carbon catalyst to activate the carbon catalyst. The present invention also provides a method for preparing a carbon catalyst comprising iron-doped nitrogen and sulfur.

The preparation of the zinc-organic ligand skeleton comprises: preparing a mixed solution by mixing a zinc precursor, an organic ligand containing nitrogen and sulfur, and polyvinyl pyrrolidone in a solvent; Preparing a first solution prepared by maintaining the prepared mixed solution at 80 캜 for 1 hour and a second solution maintained at 80 캜 for 7 to 8 hours, and a step of pouring the first solution into the second solution, And then drying at 40 to 50 < 0 > C to prepare the zinc-organic ligand skeleton, but the present invention is not limited thereto.

In preparing the zinc-organic ligand skeleton, the zinc precursor and the organic ligand containing nitrogen and sulfur may be mixed in a molar ratio of 1: (0.5 to 1.5), but the present invention is not limited thereto.

The zinc precursor may be zinc acetate · dihydrate (Zn (CH ₃ CO ₂ ) ₂ · 2H ₂ O), zinc sitate (Zn ₃ [O ₂ CCH ₂ C (OH) (CO ₂ ) CH ₂ CO ₂ ] ₂ ) , zinc chloride (ZnCl _2), zinc sulfate (ZnSO _4), zinc nitrate _{(Zn (NO 3) 2)} , zinc perchlorate _{(Zn (ClO 4) 2)} , and borate (Zn (BF ₄₎ as the _{zinc-tetrafluoro-2 )} , But the present invention is not limited thereto.

The organic ligand containing nitrogen and sulfur may be any one selected from the group consisting of dithiooxamide, thioacetamide, and thiocarbamide, But is not limited thereto.

In the step of synthesizing the iron-doped skeleton, the zinc-organic ligand skeleton and the iron precursor may be mixed with distilled water at a weight ratio of 1: (0.2-0.6), but the present invention is not limited thereto.

Said iron precursors may be hemoglobin, ferrous sulfate (FeSO _4), ferric sulfate _{(Fe 2 (SO 4) 3} ), iron nitrate (Fe (NO _3)), and ferric chloride at least one selected from the group consisting of (FeCl ₃₎ But is not limited thereto.

The carbonizing step may carbonize the iron-doped skeleton at 700 to 1000 ° C under a nitrogen atmosphere, but is not limited thereto.

The step of activating the carbon catalyst may include washing the carbon catalyst with an aqueous hydrochloric acid solution to remove the zinc particles in the carbon catalyst, but the present invention is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by these examples.

Example 1 Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

1. Synthesis of zinc-dithiooxamide (ZnDTO) skeleton

After dissolving 0.5 g of polyvinyl pyrrolidone (PVP) in 50 ml of dimethyl formamide (DMF), 0.250 g of dithiooxamide (hereinafter referred to as DTO) (0.00207 mol) and 0.456 g (0.00207 mol) of zinc acetate · dihydrate (Zn (CH ₃ CO ₂ ) ₂ · 2H ₂ O) were dissolved to prepare a mixed solution.

Using the prepared mixed solution, a first solution held at 80 DEG C for 1 hour and a second solution held at 80 DEG C for 7 to 8 hours were prepared.

The first solution was poured into the second solution and reacted to wash the reaction product to complete the reaction. The reaction product was obtained by centrifugation, washed several times with ethanol and then dried overnight at 40 to 50 ° C under vacuum to prepare a zinc-dithiooxamide skeleton, which is a polymer composed of a zinc-dithiooxamide (ZnDTO) complex Were synthesized.

2. Synthesis of iron-doped ZnDTO skeleton

ZnDTO skeleton and hemoglobin (hereinafter referred to as 'Hgb') were mixed in distilled water at a weight ratio of 1: 0.25 and stirred overnight to incorporate Hgb in the ZnDTO skeleton to synthesize iron-doped ZnDTO skeleton powders.

3. Carbonization Process

Iron-doped ZnDTO skeletal body powders were transferred to a quartz boat and then placed in a Tuuvuno. The catalyst was heated to 900 ° C. at a heating rate of 3 ° C./min in a nitrogen atmosphere, maintained at 900 ° C. for 3 hours, and then cooled to room temperature to obtain iron-doped carbon catalysts containing nitrogen and sulfur (hereinafter referred to as Fe-NSC) Were synthesized.

4. Activation of Fe-NSC

In order to activate the Fe-NSC, the Fe-NSC catalyst was obtained by washing in 37% HCl aqueous solution at room temperature and further washing with distilled water to remove unstable and inert Zn nanoparticles.

Finally, the prepared active Fe-NSC catalyst was dried under vacuum at 100 < 0 > C overnight before use. The porous Fe-NSC catalyst could be obtained by evaporating or removing zinc from the structure. The synthesized Fe-NSC was named 'Fe-NSC @ 900'.

Example 2 Synthesis of Carbon Catalyst Containing Nitrogen and Sulfur

Nitrogen and sulfur-containing carbon catalysts (hereinafter, referred to as 'NSC') were synthesized under the same conditions as in Example 1 except that hemoglobin, which is an iron precursor, was not used. Respectively.

Comparative Example 1 Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

The Fe-NSC synthesized therefrom was named 'Fe-NSC @ 700' except that the carbonization step was heated to 700 ° C. at a heating rate of 3 ° C./min.

Comparative Example 2 Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

The Fe-NSC synthesized therefrom was named 'Fe-NSC @ 800', except that it was heated up to 800 ° C. at a heating rate of 3 ° C./min in the carbonization process.

≪ Comparative Example 3 > Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

The Fe-NSC synthesized in this Example was named 'Fe-NSC @ 1000', except that it was heated to 1000 ° C. at a heating rate of 3 ° C./min in the carbonization process.

≪ Comparative Example 4 > Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

Except that ZnDTO and hemoglobin (Hgb) were mixed in distilled water at a weight ratio of 1: 0.1.

Comparative Example 5 Synthesis of Iron-doped Carbon Catalyst Containing Nitrogen and Sulfur

Except that ZnDTO and hemoglobin (Hgb) were mixed in distilled water at a weight ratio of 1: 0.7.

<Experimental Example 1>

1. Characterization of ZnDTO skeleton

Referring to FIG. 1, it is confirmed that the ZnDTO skeleton is composed of ZnDTO particles having a uniform size and perfectly spherical shape.

More specifically, referring to FIG. 1 (c), the average diameter of the ZnDTO fine particles synthesized by the first solution maintained at 80 ° C. for 1 hour was 900 ± 50 nm, and the temperature was maintained at 80 ° C. for 7 to 8 hours The mean diameter of ZnDTO of the large particles synthesized by the maintained second solution was 3000 ± 100 nm.

It was confirmed that the ZnDTO skeleton was composed of the small particles and the large particles of ZnDTO particles.

2. Characterization of Fe-NSC @ 900 and NSC @ 900

In order to confirm the shapes of Fe-NSC @ 900 and NSC @ 900 synthesized according to Examples 1 and 2, a field emission scanning electron microscope (SEM) using a field emission scanning electron microscope (FESEM; Carl Zeiss, IBRA 200Cs) Field emission scanning electron microscopy (FESEM).

Fe-NSC @ 900 and NSC @ 900 confirmed that the original ZnDTO spheres were retained.

2 (A) and FIG. 2 (A) show FESEM images of Fe-NSC @ 900 before and after cleaning. It is confirmed that Zn particles are completely dissolved from the already carbonized sample after cleaning with an aqueous acid solution Respectively.

Referring to FIG. 2 (B-a), similar shapes were observed for NSC @ 900 as for Fe-NSC @ 900. 2 (Bb) and 2 (Bc), the shapes prepared from Fe-NSC @ 700 and Fe-NSC @ 800 synthesized by Comparative Example 1 and Comparative Example 2 were almost the same, The carbonized sample of Fe-NSC @ 1000 synthesized by the method of the present invention showed some agglomerated particles in the spherical shape. In general, the structure of the organic structure at high temperature shrinks, and this phenomenon is attributable to the collapse of the ZnDTO surface texture.

3 (a) shows an XPS spectrum deconvoluted with respect to N 1s of Fe-NSC. The N 1s high resolution spectrum was able to deconvolute at four peaks, and specifically ZnDTO (N1, 397.2 eV), pyrrolic N (N3, 399.6 eV), and graphitic N (N2, 400.7 eV) with small peaks It was completely converted to oxidized nitrogen (N4, 405.0 eV). N of pyridinium, pyrrolic, and graphite is well known to play an important role in ORR and is an increasing factor in ORR performance.

3 (b), Raman spectra for various Fe-NSC catalysts are shown. To confirm the degree of graphitization for Fe-NSC, a Raman spectroscope (Horiba Jobin-Yvon, France) Raman spectroscopy was performed. D band (1345 cm ^-1 ) and G band (1592 cm ^-1 ) provided information on defect and crystallinity. Referring to FIG. 3 (b), when the temperature was increased during the carbonization process, the peak intensity ratio (I _D / I _G ) gradually decreased, suggesting that the degree of graphitization was high.

Referring to FIG. 3 (c), XRD patterns of NSC and Fe-NSC are shown. The XRD patterns of NSC and Fe-NSC show diffraction peaks at (002) and (101) , And NSC and Fe-NSC samples showed graphite structure. In addition, Fe-NSC clearly indicated diffraction peaks for Fe ₃ C (JCPDS: 34-001) in accordance with HRTEM data.

In addition, nitrogen adsorption / desorption was measured using a BELsorp-mini II instrument to confirm the specific surface area and porosity of the Fe-NSC catalyst.

3 (d), a BET surface area measurement assay for Fe-NSC is shown, wherein the NSC catalyst is a mixture of 446 m ² / g of Brunauer-Emmett-Teller 'BET') surface area, while the Fe-NSC catalyst showed a high BET surface area of 1497 m ² / g.

3. Electrocatalytic characterization of NSC and Fe-NSC

To analyze the ORR activity of NSC, Pt / C catalyst and Fe-NSC, cyclic voltammetry (CV) was used.

Referring to FIG. 4 (a), a solution of 0.1 M potassium hydroxide saturated with oxygen, while showing no reduction peak for Fe-NSC in the solution saturated with nitrogen, shows sharp reduction of Fe-NSC under 0.161 V voltage The peak appeared.

The ORR peak potential of Fe-NSC was almost the same as the peak potential of Pt / C catalyst (-0.158 V) and the initiation potential was higher than the ORR peak potential of NSC (-0.228 V) NSC catalyst showed excellent catalytic activity.

Good catalytic activity is due to the strong back bonding of the absorbed oxygen and Fe-N / C, resulting in increased O-O bond distances and facilitation of the reduction of oxygen molecules. By having a suitable ORR catalyst, the carbonization process temperature and the composition of the precursor were optimized.

Referring to FIG. 4 (b), Fe-NSC @ 900 catalysts were obtained from Fe-NSC @ 700, Fe-NSC @ 800 through a CV for Fe-NSC and a rotating disk electrode , And Fe-NSC @ 1000 catalysts. The Fe-NSC @ 900 catalyst was found to be a good ORR catalyst when compared to a range of other catalysts.

On the other hand, the Fe-NSC @ 1000 catalyst exhibited poor ORR performance. This is believed to be due to the decrease in active sites due to the collapse of some of the surface structure of the Fe-NSC catalyst at high carbonization temperatures.

The experimental results show that the Fe-doped NSC catalyst has excellent ORR activity when compared with Fe-doped NSC catalyst. Therefore, it has been proved that a suitable Fe doping step is necessary for use for ORR catalysts.

Figure 4 (c) is a Fe-NSC, NSC, and Pt / C as shown the ORR polarization curves for the catalyst, Fe-NSC catalyst with the highest potential initiation _(onset E = 0.026 V) and the half-wave potential (E _1/2 = - 0.131 V) and the highest diffusion limit current density ( J _lim = 7.20 mA / cm ² ).

ORR characteristic for NSC catalyst _{(E onset = - 0.087 V,} E 1/2 = - 0.179 V, J lim = 4.53 mA / cm 2) is characteristic for the ORR Pt / C catalyst _{(E onset = 0.028 V, E} 1 _{/ 2} = - 0.128 V, J _lim = 5.91 mA / cm ² ).

Fe doping provides an active heteroatom coordination space within the carbon material, and the provided coordination space has the advantage of performing catalytic conversion and material transport while performing the ORR.

Fe-NSC catalysts with larger particle sizes compared to Fe-NSCs with smaller particle sizes resulted in lower O ₂ diffusion and lower activity space for ORRs due to the collapse of shape and surface structure.

RDE measurements at various rotational speeds and the Koutecky-Levich (K-L) plot for various samples were used to determine the kinetic coefficients for ORR.

Referring to FIG. 4 (d), the diffusion current density increases as the rotation speed increases, and the current increases slightly when the potential shifts to negative.

Referring to FIG. 4 (e), it can be seen that the parallel line and linear line for Fe-NSC is the first-order reaction, and the number of electrons transferred on the Fe-NSC and NSC catalyst- V, which was similar to that of the Pt / C catalyst.

Referring to FIG. 4 (f), the kinetic current density of the NSC modified electrode was found to be 9.66 mA close to the kinetic current density value (13.09 mA / cm ² ) of the Pt / C catalyst modified electrode / cm ² , while the kinetic current density of the electrode modified with Fe-NSC catalyst was 45.89 mA / cm ² . This suggests excellent Fe-NSC catalyst performance.

Although the ORR activity of the NSC modified electrode is lower than that of the Fe-NSC and Pt / C modified electrode, it can be seen that the recently reported nitrogen is superior to the ORR activity of the electrode modified with the doped carbon catalyst.

Referring to Figure 5 (a), Tafel slope analysis was used to further analyze the kinetic properties of ORR for NSC, Fe-NSC, and Pt / C, .

(-63 mV / dec, -125 mV / dec) and Pt / C (-60 mV / dec) for the Fe-NSC in the lower (-58 mV / dec) mV / dec, -120 mV / dec), and confirmed that the Fe-NSC catalyst had better dynamical processes than the Pt / C catalyst.

In addition, the Fe-NSC catalyst exhibited remarkable long-term stability and methanol tolerance. For example, referring to FIG. 5 (b), the RDE measurement result of Fe-NSC after 5,000 times shows that the half-wave potential of Fe-NSC has moved to 0.002 V negative. The long-term stability was confirmed by time-current analysis (-0.2 V, 30000 sec).

Specifically, referring to FIG. 5 (c), Pt / C exhibited a high current durability with only a current density of 46.9% and a fast current loss, while Fe-NSC exhibited excellent durability with a current density of 87.1%.

Referring to FIG. 5 (d), when 3 M methanol was injected into the electrolyte solution, no significant current change was observed with respect to the Fe-NSC catalyst. In contrast, when 3 M methanol was injected into the electrolyte solution, / C catalyst, which is attributed to the oxidation of methanol on the electrode surface.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various modifications and changes may be made without departing from the scope of the appended claims.

Claims (15)

Iron precursor;
A spherical organic ligand skeleton formed to surround the iron precursor;
A graphene sheet bonded to the outside of the organic ligand skeleton; And
And carbon nanofibers bonded to the outside of the organic ligand skeleton,
The organic ligand skeleton may include,
A polymer composed of a zinc-dithiooxamide complex, a polymer composed of a zinc-thioacetamide complex, and a polymer composed of a zinc-thiocarbamide complex &Lt; / RTI &gt; carbon catalyst comprising iron-doped nitrogen and sulfur. The method according to claim 1,
The iron precursor,
Hemoglobin, ferrous sulfate (FeSO _4), ferric sulfate _{(Fe 2 (SO 4) 3} ), iron nitrate (Fe (NO _3)), and iron chloride (FeCl ₃₎ in, characterized in that any selected one from the group consisting of, A carbon catalyst comprising iron-doped nitrogen and sulfur. delete The method according to claim 1,
The organic ligand skeleton of the spherical shape may be,
Wherein the carbon catalyst comprises iron-doped nitrogen and sulfur, characterized in that it consists of spherical organic ligands having an average diameter of 850 to 950 nm and spherical organic ligands having an average diameter of 2900 to 3100 nm. A sensor comprising the carbon catalyst of any one of claims 1, 2 and 4. The method of claim 5,
The sensor includes:
Wherein the sensor is any one of a dopamine detection sensor, an ascorbic acid detection sensor, a phenol detection sensor, a toxic substance detection sensor, a heavy metal detection sensor, a hydrogen peroxide detection sensor, a glucose detection sensor, an immunity sensor or an enzyme sensor. Preparing a spherical zinc-organic ligand skeleton, which is a polymer composed of a complex by mixing a zinc precursor, an organic ligand containing nitrogen and sulfur, and polyvinylpyrrolidone in a solvent, ;
Mixing the zinc-organic ligand skeleton and the iron precursor with distilled water and stirring to synthesize an iron-doped skeleton;
Carbonizing the iron-doped skeleton in a nitrogen atmosphere to synthesize a carbon catalyst containing iron-doped nitrogen and sulfur; And
And removing the zinc in the carbon catalyst to activate the carbon catalyst. The method of claim 7,
The step of preparing the zinc-organic ligand skeleton comprises:
Preparing a mixed solution by mixing a zinc precursor, an organic ligand containing nitrogen and sulfur, and polyvinyl pyrrolidone in a solvent,
Preparing a first solution in which the prepared mixed solution is maintained at 80 캜 for 1 hour and a second solution maintained at 80 캜 for 7 to 8 hours,
Pouring the first solution into the second solution and reacting the resulting reaction product by centrifugation to obtain a zinc-organic ligand skeleton by drying at 40 to 50 ° C. Lt; / RTI &gt; The method of claim 7,
The step of preparing the zinc-organic ligand skeleton comprises:
Doped nitrogen and sulfur, characterized in that a zinc precursor and an organic ligand containing nitrogen and sulfur are mixed in a molar ratio of 1: (0.5-1.5). The method of claim 7,
Wherein the zinc precursor
Zinc acetate · dihydrate (Zn (CH ₃ CO ₂ ) ₂ · 2H ₂ O), zinc citrate (Zn ₃ [O ₂ CCH ₂ C (OH) (CO ₂ ) CH ₂ CO ₂ ] ₂ ) ZnCl _2), zinc sulfate (ZnSO _4), zinc nitrate _{(Zn (NO 3) 2)} , zinc perchlorate _{(Zn (ClO 4) 2)} , and zinc tetrafluoroborate (Zn (BF ₄₎ from the group consisting of ₂ &Lt; / RTI &gt; wherein the catalyst is one selected from the group consisting of iron-doped nitrogen and sulfur. The method of claim 7,
The organic ligand, which contains nitrogen and sulfur,
Wherein the catalyst is any one selected from the group consisting of dithiooxamide, thioacetamide, and thiocarbamide. 5. The method of claim 1, wherein the catalyst is selected from the group consisting of dithiooxamide, thioacetamide, and thiocarbamide. The method of claim 7,
The step of synthesizing the iron-doped skeleton comprises:
A process for preparing a carbon catalyst comprising iron-doped nitrogen and sulfur, characterized in that the zinc-organic ligand skeleton and the iron precursor are mixed in distilled water at a weight ratio of 1: (0.2-0.6). The method of claim 7,
The iron precursor,
Hemoglobin, ferrous sulfate (FeSO _4), ferric sulfate _{(Fe 2 (SO 4) 3} ), iron nitrate (Fe (NO _3)), and iron chloride (FeCl ₃₎ in, characterized in that any selected one from the group consisting of, Lt; / RTI &gt; A process for preparing a carbon catalyst comprising iron-doped nitrogen and sulfur. The method of claim 7,
The carbonizing step may include:
A process for producing a carbon catalyst comprising iron-doped nitrogen and sulfur, characterized in that the skeleton doped with iron is carbonized at 700 to 1000 占 폚 under a nitrogen atmosphere. The method of claim 7,
Wherein the activating the carbon catalyst comprises:
And removing the zinc particles in the carbon catalyst by washing the carbon catalyst with an aqueous hydrochloric acid solution.

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