KR20130013253A - Cu-co alloy dendrite electrode and biosensor comprising the same - Google Patents

Abstract

PURPOSE: A Cu-Co alloy dendrite electrode and a biosensor including the same are provided to apply to an electrode of the biosensor capable of detecting glucose of low concentration or hydrogen peroxide of low concentration as catalyst activation with respect to the oxidation of glucose and the deoxidation of hydrogen peroxide is excellent. CONSTITUTION: A biosensor including Cu-Co alloy dendrite electrode includes a reference electrode, a counterpart electrode, and a working electrode. The working electrode is a glassy carbon electrode or a Cu-Co alloy dendrite electrode formed on a copper plate by electrically depositing for 300-700 seconds at a potential of -0.6V to -1.2V in comparison with a reference electrode. A potential of the bio sensor is +0.4V to +0.9V in comparison with the reference electrode. The pH level of the biosensor is 10-14 and the temperature of the biosensor is 30°C-40°C. The reference electrode is an Ag/AgCl electrode.

Description

Cu-Co alloy dendrite electrodes and biosensors including the same {Cu-Co Alloy Dendrite Electrode and Biosensor Comprising the Same}

The present invention relates to a biosensor comprising a Cu—Co alloy dendrite electrode having excellent catalytic capability in both glucose oxidation and hydrogen peroxide reduction.

As an alternative to fossil fuels, monosaccharides such as glucose are renewable, inexpensive, abundant, nontoxic, nonflammable, and easy to handle, so many researchers have studied monosaccharide biobased biomass based on enzymatic catalysts such as monosaccharide oxidase such as glucose. I have been researching fuel cells. However, there is a problem in the development of enzymatic biofuel cells due to the lack of long-term stability and reproducibility due to the nature of the enzyme. Although the lifetime of enzyme biofuel cells is somewhat improved by the use of conductive polymer based enzyme electrodes, nonenzymatic fuel cells using direct electron transfer for glucose oxidation are still known to be more useful.

Early work on non-enzymatic electrochemical monosaccharide oxidation focused on the use of universal electrode materials such as C, Cu, Ni, Fe, Pt and Au. However, these materials have resulted in fundamental problems such as low efficiency and toxicity due to chemisorbed intermediates. Therefore, there is a need for development of an ideal material capable of promoting oxidation of monosaccharides such as glucose and overcoming the above problems.

On the other hand, in the form of metal catalysts, the dendrite structure is ideally suited for electrodes in electrochemical devices such as fuel cells due to its unique hierarchical structure with several active sites and extremely high surface areas. Therefore, many researchers have been studying the synthesis and catalytic activity of dendrites, but few examples have mentioned practical applications of dendrite materials.

A biosensor is a system for fixing a substance that can react with a specific substance on the surface of an electrode and converting it into an electrical signal to analyze its composition or quantity. Biosensors that use electrodes as physicochemical devices are called electrode biosensors, and when electrodes are used, they are classified into two types of methods: electric potential measurement and electric current measurement. Amperemetry refers to a method in which a fuel cell can be used as an electrode by measuring a current value obtained from an electrode reaction of a material that is consumed or produced by an enzymatic reaction at the electrode, that is, a material that easily reacts with or reacts with the electrode. have.

The inventors of the present invention are trying to develop a detection biosensor using an electrode of a current measuring biosensor as an electrode of a fuel cell, and when using a Co-Cu alloy dendrite electrode, the catalyst activity is excellent, so that a very small amount of glucose Or it was confirmed that the hydrogen peroxide can be detected and derived the optimized conditions for each compound to complete the present invention.

The present invention is to provide a biosensor for detecting glucose or hydrogen peroxide comprising a Cu-Co alloy dendrites having excellent catalytic activity.

In order to solve the above problems, the present invention is a glucose biosensor comprising a reference electrode, a counter electrode and a working electrode, the working electrode through the electrodeposition for 300 to 700 seconds at a potential of -0.6V to -1.2V A glucose biosensor is provided which is a Cu-Co alloy dendrite electrode formed on a glassy carbon electrode or a copper plate.

The glucose biosensor may have a potential of + 0.4V to + 0.9V, a pH of 10 to 14, and a temperature of 30 ° C to 40 ° C relative to the reference electrode.

In another aspect, the present invention is a hydrogen peroxide biosensor comprising a reference electrode, a counter electrode and a working electrode, the working electrode is formed of a glassy carbon electrode or a copper plate through the electrodeposition for 300 to 700 seconds at a potential of -0.6V to -1.2V It provides a hydrogen peroxide biosensor that is a Cu-Co alloy dendrite electrode formed on.

The hydrogen peroxide biosensor may have a potential of −0.3 V to −0.6 V, a pH of 6 to 8, and a temperature of 30 ° C. to 40 ° C. relative to the reference electrode.

Cu-Co alloy dendrite electrode according to the present invention is excellent in the catalytic activity for glucose oxidation and hydrogen peroxide reduction, the biosensor of detecting a very low concentration of glucose or hydrogen peroxide, such as 0.5 ± 0.1 nM, 0.75 ± 0.2 nM, respectively It can be usefully used as an electrode.

1 is a SEM image showing the shape of the Cu-Co dendrites according to an embodiment of the present invention (a: 5.0, b: 1.0㎛ scale).
Figure 2 shows the results of the EDS analysis of the Cu-Co alloy dendrites according to an embodiment of the present invention (a: whole, b: stem, c: branches).
3 is a TOF-SIMS image of a Cu-Co alloy dendrite according to an embodiment of the present invention, (a) Cu- ₃ ⁺ (m / z 190.80), (b) Co ₂ ⁺ (m / z 117.84), and (c) a Cu ₃ ⁺ (red), and Co ₂ ⁺ (green).
Figure 4 is an XRD pattern showing the atomic composition of Cu and Co of the Cu-Co dendrites according to an embodiment of the present invention.
5 is an XPS analysis result showing the metal oxidation state of the Cu-Co dendrites according to an embodiment of the present invention.
FIG. 6 shows glucose oxidation of each of (a) bare electrode GC electrode, (b) Cu dendrite electrode, (c) Co dendrite electrode, and (d) Cu-Co alloy dendrite electrode, according to an embodiment of the present invention. This is the result of measuring the related circulating voltage current (CV) (dashed line: blank solution, solid line: glucose solution).
FIG. 7 illustrates hydrogen peroxide reduction of each of (a) bare electrode GC electrode, (b) Cu dendrite electrode, (c) Co dendrite electrode, and (d) Cu-Co alloy dendrite electrode according to an embodiment of the present invention. This is the result of measuring the related circulating voltage current (CV) (dashed line: blank solution, solid line: hydrogen peroxide solution).
8 is a graph illustrating CV measurement of a double layer electrode in which Cu dendrites (a) or Co dendrites (b) are exposed to the outside according to an embodiment of the present invention. 8A shows glucose oxidation, and FIG. 8B shows hydrogen peroxide reduction.
FIG. 9 shows results of optimization experiments for pH, application potential, and temperature for use in biosensor applications of Cu—Co dendrites (A: glucose, B: hydrogen peroxide).
Figure 10a is a current-time plot with the addition of the amount of glucose in 0.1M NaOH solution, b shows a current-time plot with the continuous addition of hydrogen peroxide.

The present invention relates to a glucose or hydrogen peroxide biosensor comprising a reference electrode, a counter electrode, and a working electrode, wherein the working electrode is formed of a glassy carbon electrode or copper by electro-deposition for 300 to 700 seconds at a potential of -0.6V to -1.2V. It provides a glucose or hydrogen peroxide biosensor that is a Cu-Co alloy dendrites formed on a plate.

In one embodiment of the present invention, the reference electrode may be an Ag / AgCl electrode and the counter electrode may be a platinum electrode, but is not limited thereto.

In another embodiment of the present invention, the Cu-Co alloy dendrites may be formed by vitreous carbon (electrodeposition) for 300 to 700 seconds at an optimum potential of -0.6V to -1.2V, preferably at -0.8V for 600 seconds. GC) can be formed on the electrode. If the applied potential is greater than -0.6V, the amount of alloy formed is small and in the form of particles, while if it is less than -1.2V, a problem may occur that agglomerates of too many particles are formed around the dendrite structure. Increasing the reduction current with the time of the electrodeposition means that the Cu-Co is grown on the electrode surface, Cu-Co dendrites can be obtained through the following reaction formula.

[Reaction Scheme 1]

Cu ^{2 +} + 2e ^- ↔ Cu (E ° = 0.34 V vs . SHE)

^{Co 2 + + 2e - ↔ Co} (. E ° = -0.28 V vs SHE)

As a result of analyzing the shape of the deposited dendrites using SEM, the microstructure of the Cu-Co dendrites having a typical tree shape as shown in FIG. 1 was observed.

The Cu-Co alloy dendrite electrode is characterized in that the atomic metal content ratio of Cu and Co is 45 to 65% and 35 to 55%, more preferably the atomic metal content ratio of Cu and Co is 45 to 60% and 40-55%.

In order to determine the content ratio of Cu and Co in Cu-Co dendrites according to an embodiment of the present invention, EDX analysis was performed on Cu-Co dendrites at different points along the surface of the dendrite stems and branches. As shown in FIG. 2, the atomic metal content ratio of Cu: Co was 48.8: 51.2. The Cu content increased from the stem to the branch and the Co content decreased. This is believed to be due to the diffusion difference between Cu and Co.

In one embodiment of the present invention, when the biosensor including the Cu-Co alloy dendrites are used for glucose detection, the potential is + 0.4V to + 0.9V relative to the reference electrode, the pH is 10 to 14, The temperature may be 30 ° C to 40 ° C. More specifically, the potential may be + 0.5V to + 0.7V, a pH of 12 to 14, and a temperature of 33 ° C to 37 ° C relative to the reference electrode, but is not limited thereto.

In one embodiment of the present invention, when the biosensor including the Cu-Co alloy dendrites are used for hydrogen peroxide detection, the potential is -0.3V to -0.6V, pH is 6 to 8, compared to the reference electrode The temperature may be 30 ° C to 40 ° C. More specifically, the potential may be -0.3V to 0.5V, a pH of 6.5 to 7.5, and a temperature of 33 ° C to 37 ° C relative to the reference electrode, but is not limited thereto.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention, but the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

< Example  1> Cu , Co  And Cu - Co  Alloy Dendrite Electrode Fabrication

GC polished the Cu electrode (diameter = 3.0 mm) with a mirror finish using 0.5 micrometer alumina powder on an abrasive cloth, and then washed with distilled water. Cu dendrites or Co dendrites were fabricated in 0.1M Na ₂ SO ₄ solution containing 0.01M CuCl ₂ or 0.01M CoCl ₂ .6H ₂ O, respectively. On the other hand, Cu-Co alloy dendrites were produced by electro deposition in 0.1M Na ₂ SO ₄ solution containing 0.01M CuCl ₂ and 0.01M CoCl ₂ . At this time, the electrodeposition was carried out using Kosentech Model KST-P1 for 600 seconds at -0.8V and the mixed solution used was purged with nitrogen gas 30 minutes before the electrodeposition.

Increasing the reduction current with the time of the electrodeposition means that the Cu-Co is grown on the electrode surface, Cu-Co dendrites can be obtained through the following reaction formula.

[Reaction Scheme 1]

Cu ^{2 +} + 2e ^- ↔ Cu (E ° = 0.34 V vs . SHE)

^{Co 2 + + 2e - ↔ Co} (. E ° = -0.28 V vs SHE)

In addition, the double layer dendrites were produced through two steps. In the case of Cu // Co bilayer dendrites, Cu dendrite was first produced in this manner, then 0.01 M CoCl ₂ .6H ₂ O was added to the solution and Co dendrites were formed on the Cu dendrites. Co // Cu bilayer dendrites were prepared in a similar manner to the above method, but by changing the order of Co and Cu. The electrode was then washed several times in the order of 0.1 M HCl solution, acetone, ethanol and water.

< Example  2> Cu , Co  And Cu - Co  Examination of physical properties of alloy dendrites

One. SEM  image

As a result of analyzing the shape of the dendrite deposited in Example 1 using SEM, it was possible to observe the microstructure of the Cu-Co dendrite material having a typical multi-tree shape as shown in FIG.

2. EDX  analysis

In order to determine the content ratio of Cu and Co in the dendrites deposited in Example 1, EDS analysis was performed for Cu-Co dendrites at different points along the surface of the dendrites stems and branches. As shown in FIG. 2, the atomic metal content ratio of Cu: Co was 48.8: 51.2. The Cu content increased from the stem to the branch and the Co content decreased. This is believed to be due to the diffusion difference between Cu and Co. The atomic metal content ratio of Cu: Co at various positions is shown in Table 1 below. An appropriate concentration gradient of metal ions is known to be essential for the successful growth of well-defined dendrites.

Atomic metal content ratio (%) all stem Branch Cu 48.8 49.3 54.9 Co 51.2 50.7 45.1

Mass spectra and images were acquired using TOF-SIMS in positive mode to investigate the distribution of Cu and Co during dendrite formation. Figure 3 is an image of Cu-Co alloy dendrite ^{_{(a) Cu- 3 + (m}} / z 190.80), (b) Co 2 + (m / z 117.84), and ^{_{(c) Cu 3 + (red}} ) and Co relates to a ₂ ⁺ (green) of the overlay element ion. The analysis area is 10 × 10 μm ² , and the bright part of the TOF-SIMS image shows the high distribution of each element. Cu- ₃ ⁺ ions, and was determined to Co ₂ ^+, which is most often distributed to show a clear signal, such TOF-SIMS image is similar to a form that can be seen in the SEM image of the Department. Cu and Co accumulated very closely and complementarily in the process of dendrite formation. This uniform distribution of Cu and Co in the porous alloy dendrites makes the catalysis of glucose oxidation and H ₂ O ₂ reduction easier.

3. EDX  analysis

In order to determine the Cu-Co metal state in the dendrites deposited in Example 1, the XRD pattern was analyzed using the X'pert PRO MRD system model, and three clearly distinguished main peaks as shown in FIG. Observed at 2θ ° of, 50 and 73, and incidental peaks were observed at 2θ ° of 44 and 51, indicating a crystallized structure, all surface peaks identified as face centered cubic (fcc), electro-deposited fcc copper And at diffraction angles corresponding to fcc cobalt. The peak intensity of Co was stronger than the peak intensity of Cu, which is consistent with the EDX results. Cu-Co diffraction peaks were very distinct and confirmed that the alloy was successfully formed on the electrode.

4. XPS  analysis

The oxidation state of the metal in the dendrites deposited in Example 1 was analyzed by XPS using a VG Scientific ESCALAB 250 XPS spectrometer with monochromatic Al Kα source including charge compensation in KBSI. The potential of glucose oxidation was 0.7 V and the hydrogen peroxide reduction potential was -0.6 V.

As it is shown in FIG. 5, XPS spectra of the dendrite (a) Cu2p _3/2, and (b) shows a Co2p _3/2 peak. Spectrum (I) relates to pure dendrites formed at -0.8V for 600.0 seconds, Spectrum (II) relates to dendrites oxidized in 0.1M NaOH solution at 0.7V, and spectrum (III) is 1.0 at 0.7V. Dendrites oxidized in 0.1 M NaOH solution containing mM glucose, spectrum (IV) relates to dendrites reduced in PBS containing 1.0 mM H ₂ O ₂ at −0.6 V.

As can be seen in FIG. 5, the pure dendrites of spectrum (I) showed peaks at 932.0 and 778.2 eV positions corresponding to Cu ⁰ and Co ⁰ , respectively, wherein Cu and Co are in the reduced metal state.

In spectrum (II) of FIG. 5 (a), the peak at 932.0 eV, broadly covering 932.5 and 934.6 eV of Cu ⁰ , corresponds to the formation of Cu ⁺ (932.5 eV) and Cu ²⁺ (934.6 eV), 940.0-943.5 additional broad peak over eV is due to the formation of Cu ^{+ 2.} In this case, the strength of the Cu + peak at 932.5 eV is s overwhelming than the strength of Cu ^{2 +} peak at 934.6 eV, which blank in the oxidation of the dendrites of the NaOH solution, the formation of Cu ⁺ ions, plenty the formation of Cu ^{2 +} ions Suggests.

The spectrum (Ⅱ) of FIG. 5 (b), a small peak of 781.1 and 780.1 eV in Co ⁰ corresponds to the Co ^{2 +} and Co ^{3 +} form, additional small peak of 784.9 around 787.0 eV is Cu ^{2 +} and Co ^Due to ³⁺ formation. In this case, Co ^{2 +} (781.1eV) peaks suggest the formation of Co ^{2 +} ions, plenty the formation of Co ^{3 +} ion in the oxidation process of the dendrites of the s overwhelming, which blank NaOH solution than Co ³⁺ (780.1 eV) do. When 1.0 mM glucose was oxidized in the dendrites present in the NaOH solution, the Cu ⁺ peak intensity was observed in spectrum (III) of FIG. 5A to appear identical to the Cu ⁰ intensity, the peak corresponding to the oxidized Cu and Co ions. Was higher than Cu and Co metals. This means that the dendrite surface is mainly oxidized to the Cu ⁺ state in the presence of glucose, which is due to further catalytic oxidation due to the presence of glucose.

XPS spectra for the hydrogen peroxide (H ₂ O ₂ ) reduction reaction were obtained when dendrites were used as the electrode for the reduction reaction at -0.6V with and without hydrogen peroxide.

In the blank solution (PBS) without hydrogen peroxide, only peaks corresponding to Cu ⁰ and Co ⁰ were detected at 932.0 and 778.2 eV, respectively (see FIG. 5 (I)). On the other hand, after applying a reduction potential of -0.6 V to the dendrites of the PBS containing 1.0 mM H ₂ O ₂ , as shown in (IV) of FIG. Peaks were detected with the main Cu and Co metal peaks. In this case, however, Cu ^{2 +} intensity peak (934.6 eV) of the ions is higher than the peak intensity of Cu ⁺ (932.5 eV), than the strength of the Co ^{3 +} peak (780.1 eV) strength of Co ^{2 +} (781.1 eV) of High. When the relative peak intensities of the oxidized ions formed on the dendrite surface during the reduction hydrogen reduction process are compared with the glucose oxidation process, the Cu and Co ions on the dendrite surface are associated with both the catalytic redox reaction of glocose and hydrogen peroxide. And it was found. In the case of glucose oxidation dendrite surface was formed much after glucose oxidation as compared to Cu ^{+ 2} and Co ⁺ is Cu ^{2 + 3} and Co ^+. While H ₂ O ₂ After the reduction is the Cu ^{+ 2} and Co ^{+ 3} was formed than Cu ^{+ 2} and Co ^+. With this result, Cu ^{+ 2} and Co ^{+ 3} is generated by at +0.7 V of the oxidation of glucose solution in den Dendrite surface is reduced to Cu ^{+ 2} and Co ⁺ through a catalytic reaction of oxidation of glucose, the hydrogen peroxide It was found that Cu ⁺ and Co ^{2 +} produced by the oxidation of Cu ^{2 +} and Co ^{3 +} due to the catalysis of hydrogen peroxide reduction reaction at -0.6V. According to these results, the dendrite surface will be present with various kinds of oxide ions such as Cu ⁺ , Cu ^{2 +} , Co ^{2 +} , and Co ^{3 +} , which means Cu ₂ O, CuO, Cu (OH) at the dendrite surface. ₂ , CoO, Co (OH) ₂ , Co ₂ O ₃ , CoOOH and the like.

5. Electrochemical Catalytic Analysis of Glucose Oxidation at Dendrites

In order to measure the glucose oxidation mechanism in Cu-Co alloy dendrites, the number of electrons participating in the glucose oxidation reaction was investigated using controlled potential coulometry and HPLC-ESI MS analyzer.

Whole volume assays were performed for each solution comprising 5.0 mL blank (0.1 M NaOH) and 1.0 μM glucose solution. The glucose oxidation potential was applied at + 0.6V for 100 minutes, and in both cases, the Q values were maintained at -19.7 and -25.5 mC for 100 minutes, respectively. As a result of the total analysis, glucose oxidation was found to be performed through 12.02 ± 0.15 electrons in the Cu-Co alloy dendrites. The glucose negative electrode products of Cu, Co and Cu-Co dendrites were analyzed by HPLC-ESI MS system and the results are shown in Table 2.

The Cu dendrite electrode oxidized glucose to 97% with formic acid, a product containing 12-electrons, which is consistent with the results of the prior literature that the Cu electrode oxidizes glucose with formic acid without side reactions. In contrast, Cu-Co dendrite electrodes oxidized glucose to formic acid 90.4%, and oxidized to glycolate (3.2%), oxalate (1.4%), glucalate (1.9%), and glycelate (1.2%). I was. In the Co dendrites, glucose was oxidized about 75.8% with formic acid, and the same side reaction products as the Cu-Co dendrites were detected.

6. Circulating voltage current CV ) analysis

To evaluate the catalytic characteristics of the dendrites of Example 1 in the oxidation of glucose, the negative electrode GC, Cu, Co and Cu-Co alloy dens in 0.1 M NaOH solution (dotted line) and 10.0 mM glucose containing solution (solid line) Cyclic voltage current (CV) for the dry was measured (see FIG. 6).

As a result, no reduction peak with respect to the bare electrode GC was observed in the blank solution as shown in FIG. On the other hand, the CV for the Cu dendrite electrode showed a redox peak (E _pc / E _pa ) at + 0.28 / + 0.37 V as shown in b of FIG. 6, and the CV for the Co dendrite electrode as shown in FIG. Shows a redox peak (E _pc / E _pa ) at + 0.14 / + 0.18 V. This is consistent with the redox couples of Cu and Co itself. As in d in FIG. 6, redox peaks for the Cu—Co alloy dendrites were observed near + 0.16 / + 0.20 in the blank solution.

The cyclic voltammograms (CV) indicated by solid lines in FIG. 6 are for Cu, Co and Cu-Co alloy dendrites in 0.1 M NaOH solution containing 10.0 mM glucose. The catalytic oxidation peak of glucose to gluconic acid at the Cu dendrite electrode was observed at +0.51 V and the peak current was determined to be 105.9 μA (FIG. 6 b). In the case of Co dendrites, the peak current on glucose oxidation was observed at +0.56 V, which was higher than Cu and the catalytic peak current was determined to be 111.7 μA (FIG. 6 c). In contrast, the oxidation peak of glucose in Cu—Co alloy dendrites was observed at +0.57 V, which was higher than that of Cu or Co alone dendrites (FIG. 6 d). The catalytic peak current of glucose oxidation recorded for the Cu—Co alloy dendrites was 1.11 mA, which was 10.5 and 9.9 times higher than Cu or Co alone dendrites, respectively. The peak was corresponding to the oxidation of Cu ⁺ Cu ^{2 +} oxidation and Co ^{2 +} Co ^{3 +} to the contained in the catalysis of the glucose oxidation at a pH 13 solution electrode. Cu ^{+ 2} and Co ⁺ is oxidized to the first electrochemically Cu ^{+ 2} and Co ^{+ 3,} then it is determined that reacts with glucose to produce an oxide and the regeneration of the catalyst takes place.

In addition, in order to investigate the catalytic potential of the dendrite electrode for air, oxygen or hydrogen peroxide reduction, the bare electrode GC, Cu, in 0.1 M PBS (pH 7.0, dotted line) and 10.0 mM H ₂ O ₂ containing PBS (solid line) CVs for the Co and Cu—Co alloy dendrites were measured (see FIG. 7). In the blank buffer, no reduction peak was observed in the bare electrode GC (FIG. 7 a). On the other hand, the CV for Cu dendrite electrode showed a cathode peak at -0.16V (FIG. 7B), and the CV for the Co dendrite electrode showed a cathode peak at -0.43V (C of FIG. 7). which was reduced corresponding to the reduction of Co ^{2 +} Cu ^{2 +} to the Cu ⁺ and Co ^{+ 3,} respectively. As shown in FIG. 7 (d), the cathode peak in CV for the Cu—Co alloy dendrites was found to be -0.22 V in the blank solution. The catalytic performance of the dendrites showed the highest peak in hydrogen peroxide reduction compared to air and oxygen. CVs for dendrites in hydrogen peroxide solutions are shown in solid lines in FIG. 7. The catalytic reduction peak of hydrogen peroxide to water at the Cu dendrite electrode was observed at -0.23 V and the peak current was 165.0 μA. For Co dendrites, a hydrogen peroxide reduction peak was observed at -0.39 V, which was more positive than Cu dendrites and the catalytic peak current was 230.4 μA. In contrast, the catalytic peak current of hydrogen peroxide measured for Cu-Co alloy dendrites was 673.4 μA at -0.31 V, which was 4.1 and 2.9 times increased compared to that of pure Cu and Co dendrites, respectively. .

In order to confirm the role of the single metal Co and Cu in the catalysis, as described in Example 1, the single metal dendrite Co and Cu was produced in a double layer structure. Co dendrites formed on the inner layer Cu dendrites surface exhibited greater activity than those of Cu dendrites formed on the surface of the Co dendrites inner layer exposed to the solution. Bilayer dendrites are composed of either Cu or Co dendrites, either glucose or H ₂ O ₂ It was prepared by the method of Example 1 to see if it further contributed to the catalytic effect of the reaction.

FIG. 8A shows a double layer electrode exposed to the outside of Cu dendrites (a) or Co dendrites (b) at −0.1 to +0.7 V, −0.1 M NaOH (dashed line) and 1.0 mM glucose (solid line), 50.0 mV / s. Relates to a CV measurement graph for. The redox peak was observed at + 0.18 / + 0.37 V when Co // Cu double layer dendrites were in the blank (NaOH) solution, and + 0.15 / + 0.27 V for Cu // Co bilayer dendrites. Solid lines in FIG. 8A show Co // Cu in a NaOH solution containing 1.0 mM glucose. Or it relates to the cyclic voltage current (CV) of the Cu / / Co double layer dendrites. The oxidation peak of glucose was + 0.60V at the Co // Cu double layer dendrites and the cathode peak current was 171.5 μA. Was Cu // Co appeared double charge in den Dendrite electrodes to glucose oxidation peak of + 0.62V, the negative peak was shown in a more positive than that of the Cu-layer Co // dendrite electrode negative peak current of Co // Cu Twice, 336.2 μA.

8B, (a) shows Co // Cu double layer dendrites and (b) shows -0.1M NaOH (dotted line) and 1.0 mM glucose at +0.1 to -0.6V for the Cu // Co double-fill dendrite electrodes. (Solid line) It is a graph of CV measurement with respect to a solution. Cathode peaks were observed at -0.24V for Co // Cu and -0.28V for Cu // Co in a blank (NaOH) solution. Solid lines show Co // Cu in a PBS solution containing 1.0 mM H ₂ O ₂ Or it relates to the cyclic voltage current (CV) of the Cu / / Co double layer dendrites. The catalytic cathode peak upon conversion of H ₂ O ₂ to H ₂ O was observed at -0.27 V in Co // Cu double layer dendrites, with a cathode peak current of 279.6 μA. Cu // Co H ₂ O ₂ of double layer dendrites The peak was observed at -0.32V, which is lower than that of Co // Cu double layer dendrites, with a cathode current of 373.6 μA, 1.3 times. Through the above results, the Co // Cu or Cu // Co Bilayer dendrite composition showed better catalytic performance in both glucose oxidation and hydrogen peroxide reduction than those of Cu and Co alone.

As discussed above, Cu-Co dendrite exhibited excellent catalytic capacity in both glucose oxidation and hydrogen peroxide reduction compared to conventional Cu and Co electrodes, and therefore, the inventors of the present invention found that Cu-Co dendrites We fabricated a biosensor for detecting hydrogen peroxide and examined its performance.

< Example  3> Manufacturing and performance measurement of glucose or hydrogen peroxide sensor

In order to use the Cu-Co dendrite electrode for glucose and hydrogen peroxide detection applications, optimization experiments were performed for pH, applied potential, and temperature, and the results are shown in FIG. 9 (A: glucose, B: hydrogen peroxide). The optimum pH, application potential and temperature for glucose detection were 13.0, +0.65 V and 35.0 ° C., respectively, and the optimum pH, application potential and temperature for detection of hydrogen peroxide were 7.0, -0.5 V and 35.0 ° C., respectively.

Under the optimized conditions, current measurements were performed on biosensors of glucose and hydrogen peroxide. 10A shows a typical current-time plot with the addition of the amount of glucose in 0.1 M NaOH solution. The potential applied to the electro-oxidation of glucose through the Cu-Co dendrites was + 0.6V. The oxidation current rapidly increased as the potential was applied to reach a stable value. The calibration curve shows the current response of glucose. As the amount of glucose increased, the current difference increased negatively. The response of glucose was linear in the range from 5.0 nM to 1.4 mM, with a correlation coefficient of 0.999. The limit of detection of glucose through the Cu-Co dendrites was found to be 0.5 ± 0.1 nM.

10B shows a general current-time plot with the continued addition of hydrogen peroxide. Steady state response was seen when the potential was -0.35V. The calibration curve was obtained through the current reaction of the dendrite electrode, the current response was linearly related to the amount of hydrogen peroxide, and the correlation coefficient was 0.998 when the hydrogen peroxide range was 10.0 nM to 1.1 mM. The limit of detection of hydrogen peroxide through the Cu-Co dendrites was 0.75 ± 0.2 nM.

These results suggest that Cu-Co dendrite has a catalytic activity against glucose oxidation and hydrogen peroxide reduction and thus can be widely used as a catalyst for fuel cells, glucose and hydrogen peroxide sensors.

Having described the specific parts of the present invention in detail, it will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, and thus 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 (6)

In a glucose biosensor comprising a reference electrode, a counter electrode and a working electrode, the working electrode is formed of Cu—formed on a glassy carbon electrode or a copper plate through electrodeposition for 300 to 700 seconds at a potential of −0.6 V to −1.2 V. Glucose biosensor that is a Co alloy dendrites electrode.
The method of claim 1,
The biosensor has a potential of +0.4 V to +0.9 V, a pH of 10 to 14, and a temperature of 30 ° C. to 40 ° C. relative to the reference electrode.
The method of claim 1,
The reference electrode is a glucose biosensor that is an Ag / AgCl electrode.
In a hydrogen peroxide biosensor comprising a reference electrode, a counter electrode, and a working electrode, the working electrode is formed of Cu— formed on a glassy carbon electrode or a copper plate through electrodeposition for 300 to 700 seconds at a potential of −0.6 V to −1.2 V. Hydrogen peroxide biosensor that is a Co alloy dendrite electrode.
5. The method of claim 4,
The biosensor is a hydrogen peroxide biosensor that has a potential of -0.3V to -0.6V, a pH of 6 to 8, a temperature of 30 ℃ to 40 ℃ compared to the reference electrode.
5. The method of claim 4,
The reference electrode is a hydrogen peroxide biosensor that is an Ag / AgCl electrode.

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