• 전기화학회지
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• 제6권2호
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• pp.158-160
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• 2003

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400 F/g (specific capacitance) and good cycleability. But, it had serious demerits of low voltage range under 0.5 V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. We report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over 250 F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100 F/g capacitance. This capacitance was only electric double layer capacitance of active surface area. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Itis very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.93-96
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• 2001

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400F/g (specific capacitance) and good cycleability. But, It had serious demerits of low voltage range under 0.5V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. we report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over than 250F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around l00F/g capacitance. This capacitance was only surface EDLC. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Its very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.93-96
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• 2001

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400F/g (specific capacitance) and good cycleability. But, It had serious demerits of low voltage range under 0.5V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. we report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over than 250F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100F/g capacitance. This capacitance was only surface EDLC. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Its very hard to reach resistive layer. So, e have studied on pretretmetn of electrode to contain working ions easily. We'll report more details.

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.995-999
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• 1996

A method for the determination of cobalt(Ⅱ) by differential pulse voltammetry using a carbon paste electrode constructed by incorporating 1-(2-pyridylazo)-2-naphthol(PAN) into a conventional carbon paste mixture composed of graphite powder and Nujol oil has been developed. Several influencing factors for the determination of cobalt(Ⅱ) were studied in detail and the optimum analytical conditions were found to be as follows: pH, 4.6; composition of electrode, 20%; temperature of deposition, 43 ℃; time of preconcentration, 15 min. Regeneration of the electrode surface for the continuous uses of the electrode was achieved by exposing the carbon paste electrode to an acidic solution. Response of the electrode was reproducible for the uses of five times and the relative standard deviations were 6.7 and 4.6% for 2.0×10-5 M and 4.0×10-6 M cobalt(Ⅱ), respectively. The calibration curve for cobalt(Ⅱ) obtained by differential pulse voltammetry was divided into two linear ranges of 1.7× 10-6-1.3×10-4 M and 2.0×10-7-8.0×10-7 M. The detection limit was estimated to be 1.3×10-7 M. The effects of coexisting ions were also investigated to test the applicability of the proposed method to the determination of cobalt(Ⅱ) in real samples.

• 한국세라믹학회지
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• 제45권8호
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• pp.482-485
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• 2008

Composite electrode consisting of carbon nanofiber (CNF) and cobalt oxide was prepared for supercapacitor electrode, and its electrochemical property was investigated by means of cyclic voltammetry. Cyclic voltammetric results for the composite electrode showed it had specific capacitance value of 420 F/g at 5 mV/s, which was higher than capacitance value of 180 F/g for the bare CNF. It is concluded that the capacitive property of CNF can be improved by coating cobalt oxide on it to increase the surface area of cobalt oxide.

• 한국세라믹학회지
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• 제45권6호
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• pp.368-373
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• 2008

An electrode for supercapacitor using 3-dimensional porous nickel foam as a current collector and cobalt oxide as an active material was prepared and characterized in terms of morphology observation, crystalline property analysis, and the investigation of electrochemical property. The electrode surface showed that the cobalt oxide was homogeneously coated as the crystalline phase of $Co_3O_4$. Cyclic voltammetry for the $Co_3O_4$/nickel foam electrode exhibited higher specific capacitance values (445 F/g at 10 mV/s and 350 F/g at 200 mV/s) and excellent capacitance retention ratio (99% after $10^4$ cycles). It was proved that the nickel foam substrate played the roles in reducing the interfacial resistance with cobalt oxide and in improving the electrode density by embedding greater amount of cobalt oxide within it.

• Journal of Electrochemical Science and Technology
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• 제6권4호
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• pp.111-115
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• 2015

In this work electrochemical oxidation of Ascorbic acid (AA) on the surface of Cobalt nano particle modified carbon paste electrode (CoNPsMCPE) was studied in alkaline media. CoNPs were green synthesized using Piper longum and a mixture of 5% (w/w) of it were made with carbon paste. CoNPs showed good electrocatalytic activity in alkaline media. Cyclic voltammetry (CV) and chronoamperometry (CA) were used to study the electrochemical performance of CoNPsMCPE. The number of monolayers on the surface of electrode was calculated as 1.08×10⁹ mol cm⁻² that is equal to that of metal Cobalt electrode. Diffusion coefficient of AA was determined using CA analysis which was equal to 1.5×10⁻⁶cm² s⁻¹.

• 한국표면공학회지
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• 제52권3호
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• pp.180-185
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• 2019

The demands to improve the performance of the vanadium redox flow battery have attracted an intense research on modifying the carbon-based electrode. In this study, the surface of graphite felt was reformed, using cobalt oxide. The cobalt oxide was implanted into graphite felt during hydrothermal and two step heat treatments. The cobalt was deposited by hydrothermal method and the two step heat treatments made lots of holes on the graphite felt surface which is called as porous surface. The porous surface acts as an electrochemically active site for the cathodic reaction of vanadium redox flow battery. The reformed electrode shows the electrochemically improved performance compared with the pristine electrode.

• 통합자연과학논문집
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• 제7권3호
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• pp.188-192
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• 2014

Determination of cobalt(III) ion with a perfluorinated sulfonated polymer-ethylenediamine (nafion-en) modified glassy carbon electrode is studied. It is based on the chemical reactivity of an immobilized layer, nafion-en, to yield complex $[Co(en)_3]^{3+}$. The reduction peak potential by differential pulse voltammetry (DPV) is observed at $-0.437{\pm}0.047$ V (vs. Ag/AgCl). The linear calibration curve is obtained in cobalt(III) ion concentration range $1.0{\times}10^{-8}{\sim}1.0{\times}10^{-3}M$ ($5.893{\times}10^{-12}{\sim}5.893{\times}10^{-5}g/mL$).

• 대한화학회지
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• 제37권8호
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• pp.735-743
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• 1993

Cofacial bis-cobalt tetraphenylporphyrin(Co-TPP) 유도체 화합물들이 수식된 유리질 탄소 전극과 carbon microelectrode을 작업 전극으로 사용하여 여러가지 pH 용액에서 순환 전압전류법 및 시간 전류법에 의해 산소의 환원반응을 조사하였다. 산성용액에서 monomer인 cobalt tetraphenylporphyrin 화합물이 수식된 전극에서 산소의 환원반응경로는 중간 생성물인 H$_2$O$_2$로 가는 2전자 반응으로, dimer인 cofacial bis-cobalt tetraphenylporphyrin 유도체 화합물들이 수식된 전극에서는 최종 생성물인 H$_2$O로 가는 4전자 반응으로 진행되었다. 이와 같은 산소의 환원반응은 전체적으로 비가역적이며 확산지배적인 반응으로 주어졌다. pH 변화에 따른 산소의 환원전위는 pH 13에서 pH 4 까지는 직선관계가 성립하였으나 강한 산성용액에서는 이들 관계가 성립하지 않았다. 산성용액에서 산소의 환원전위는 알몸 유리질 탄소전극에서 보다 monomer Co-TPP 화합물이 수식된 유리질 탄소전극에서는 400 mV만큼, dimer Co-TPP 화합물이 수식된 전극에서는 750 mV 만큼 더 양전위 방향으로 이동되었다.