著者

Kasumi NAKAGAWA Michiki TAKEUCHI Mayu KIKUCHI Suzuna KIYOFUJI Masami KUGO Takaiku SAKAMOTO Kenji KANO Jun OGAWA Eiji SAKURADANI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

pp.20-00123, (Released:2020-10-15)

参考文献数

29

被引用文献数

15

---

Indigo is one of the oldest natural blue dyes. Microorganisms and their enzymatic activities are deeply involved in the traditional indigo staining procedure. To elucidate the mechanism of the microbial indigo reduction, we directly performed cyclic voltammetry on alkaline fermenting dye suspensions. A pair of characteristic redox peaks of leuco-indigo was observed in a supernatant fluid of the fermenting dye suspension. On the other hand, it was found that the indigo/leuco-indigo redox couple mediated two-way microbially catalyzed oxidation and reduction in a sediment-rich suspension of the fermenting suspension. Acetaldehyde was supposed to be the electron donor and acceptor of the catalytic reactions. In order to verify the bioelectrocatalytic reaction, we isolated indigo-reducing bacterium K2-3′ from the fermenting suspension, and the two-way bioelectrocatalysis was successfully restaged in a model system containing K2-3′ and methyl viologen (as a soluble mediator instead of indigo) as well as acetaldehyde at pH 10.

著者

德島 高

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.9, pp.756-761, 2014-09-05 (Released:2014-09-05)

参考文献数

46

被引用文献数

1

著者

Tetsuya TOBA Kouji YASUDA Toshiyuki NOHIRA Xiao YANG Rika HAGIWARA Koki ICHITSUBO Kenta MASUDA Takayuki HOMMA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.7, pp.559-565, 2013-07-05 (Released:2013-07-05)

参考文献数

56

被引用文献数

19 31

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Direct electrolytic reduction of SiO2 was investigated in molten CaCl2 at 1123 K as a fundamental study to develop a continuous process for solar-grade Si production. Several different types of SiO2 granules, as well as SiO2 pellets, were successfully reduced to Si on the bottom cathode of a Si plate. Three parameters were varied in the reduction of SiO2 granules: electrode potential, layer thickness of the SiO2 granules, and SiO2 particle size. The reduction rate was evaluated by the magnitude of the reduction current. The main factor determining the reduction rate was the diffusion of O2− ions inside the reduced porous Si layer filled with the electrolyte. Another factor which influenced the reduction rate was the contact resistance between Si granules.

著者

Shu ZHANG Waheed MIRAN Divya NARADASU Siyi GUO Akihiro OKAMOTO

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

pp.20-00021, (Released:2020-04-21)

参考文献数

34

被引用文献数

9

---

Microbial extracellular electron transfer (EET) in diverse environments has gained increasing attention. However, the EET capability of oral pathogens and associated mechanisms has been scarcely studied. Here, our results suggest that the Capnocytophaga ochracea, an etiological human pathogen showed current production and demonstrated a rate enhancement of electron transport at a high cell-density. C. ochracea produced ∼10-fold more current at an OD600 of 0.5 associated with twice a higher glucose consumption rate per cell, compared to 0.1, measured in a three-electrode electrochemical system by single-potential amperometry at +0.2 V (vs Ag/AgCl [sat. KCl]). During current production, the accumulation of the redox molecules on the electrode was observed at high OD600 compared to low OD600. Apart from cell released redox active product, externally added redox active additives enhanced the electron transport, suggesting the EET capability of C. ochracea via electron mediator. A higher metabolic activity via single-cell assay (based on anabolic incorporation of 15NH4+) in cells that did not attach to the electrode strongly suggests the EET rate enhancement through an electron mediator. As bacterial populations play a role in the pathogenesis of human infections such as periodontitis, our results suggest that population-induced EET mechanisms may facilitate in-vivo colonization of C. ochracea.

著者

北折 典之 吉岡 眞由子 関戸 広太 大西 則彦 前田 菜花 松石 早矢

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.8, pp.627-633, 2013-08-05 (Released:2013-08-05)

参考文献数

22

被引用文献数

1 3

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Two kinds of small-sized electrolyzed water generator to be driven with a dry cell were investigated for sterilization in homes. These generation devices were able to produce the electrolyzed water which was weak acidic electrolyzed water or ozonated water. The weak acidic electrolyzed water was manufactured with the electrolysis of mixed solution of sodium chloride and citric acid, and ozonated water was formed by SPE (Solid Polymer Electrolyte) electrolysis of pure water. In this paper, it was reported about ability of weak acidic electrolyzed water and ozonated water for generation, sterilizing property and safety as performance of generator.

著者

Shinichi KOMABA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.87, no.6, pp.312-320, 2019-11-05 (Released:2019-11-05)

参考文献数

108

被引用文献数

12

---

Rechargeable batteries are capable of storing electric energy on the basis of pairing electrochemical redox reactions to realize sustainable energy society in our future. Since lithium-ion batteries with the highest specific energy among all the practical batteries were commercialized in 1991, many studies on lithium insertion materials and their electrochemical characterization have been reported to achieve even higher energy density, longer cycle life, and safer lithium-ion battery technologies. It is quite fortunate that the author had an opportunity to contribute to the research and development of lithium battery materials since 1997. In particular, studies on the influence of dissolved metallic ions like Mn2+, Co2+, Ni2+, Na+, and K+ ions in electrolyte solution on graphite negative electrodes in lithium-ion batteries motivated the author to extend the research scope to electrochemical sodium insertion chemistry. Furthermore, the author’s research experiences as a postdoctoral fellow in Dr. Delmas’ group in FY 2003 and a remarkable oral presentation on alpha-NaFeO2 electrode properties given by Professor Okada’s group in 2004 provided motivations and opened up new avenue toward the successful demonstration of non-aqueous sodium-ion batteries later in the career. Since 2009, the author’s research group has successfully demonstrated 3-volt class charge and discharge of a sodium-ion battery of a NaNi1/2Mn1/2O2 // hard carbon cell and a brand-new potassium-ion battery of a K2Mn[Fe(CN)6] // graphite cell. The systematic studies of three different alkali-metal insertion systems synergistically induce deeper understanding and faster development of new materials for the next-generation rechargeable batteries.

著者

芦原 聡

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.9, pp.762-765, 2014-09-05 (Released:2014-09-05)

参考文献数

21

著者

佐藤 祐一 大澤 康彦

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.9, pp.782-786, 2014-09-05 (Released:2014-09-05)

参考文献数

3

著者

上岡 永佳 渡邉 一哉

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.84, no.2, pp.104-106, 2016-02-05 (Released:2016-02-05)

参考文献数

16

著者

Koichi MITSUDO Takahiro OKADA Shuichi SHIMOHARA Hiroki MANDAI Seiji SUGA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.5, pp.362-364, 2013-05-05 (Released:2013-05-05)

参考文献数

14

被引用文献数

1 22

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An electro-reductive halogen-deuterium exchange reaction in CD3CN has been developed. Using 9-fluorenone as a mediator, the electro-reduction of several aryl halides proceeded smoothly to give the deuterated products selectively. A methylation reaction of aryl halides also proceeded under similar conditions.

著者

Keishi MATSUO Yoshiyuki TAKATSUJI Masahiro KOHNO Toshiaki KAMACHI Hideo NAKADA Tetsuya HARUYAMA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.9, pp.721-724, 2015-09-05 (Released:2015-09-05)

参考文献数

10

被引用文献数

7 12

---

Efficient generation of oxygen radicals and reactive oxygen was successfully performed at the dispersed-phasic interface between vapor-water and oxygen plasma in a reaction chamber having an internal atmosphere with a normal-pressure and temperature. In the space of the reactor chamber (radical vapor reactor [RVR]), the gas phase was strictly controlled in terms of vaporized water (small water mist), temperature, plasma conditions, and UV irradiation. According to spin-trapping electron spin resonance analysis, the RVR efficiently and quantitatively yielded two types of reactive oxygen species (1O2 and OH radical) with the atmosphere of the RVR chamber. This is the report of the efficient, quantitative production of reactive oxygen in an atmosphere. The reactivity of the produced 1O2 and OH radical may be applicable for various chemical processes, such as oxidation and electron absorption.

著者

Mika FUKUNISHI Tatsuo HORIBA Mouad DAHBI Kei KUBOTA Satoshi YASUNO Shinichi KOMABA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.87, no.1, pp.70-77, 2019-01-05 (Released:2019-01-05)

参考文献数

24

被引用文献数

4

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A nanometer-sized Sn (nano-Sn) powder composite electrode with polyacrylate binder delivers a discharge capacity of 600 mAh g−1 with a good capacity retention for 100 cycles in non-aqueous Na cells, however, a micrometer-sized Sn (micro-Sn) composite electrode exhibits an insufficient cycle performance under the same condition. Although surface analysis of cycled electrodes reveals no apparent difference in solid electrolyte interphase layer formed on the nano- and micro-Sn electrodes, we found that in the case of nano-Sn electrodes the moderately porous composite layers and thin binder coating on Sn particles are responsible for a favorable cycle performance. On the other hand, the dense and less-porous micro-Sn electrode having a relatively thicker coating of binder on micro-Sn particles deteriorates the reversibility of sodium alloying reaction. Therefore, we optimize the electrode preparation process to introduce the suitable porosity and properly thin binder coating in the micro-Sn composite electrodes. The optimization enables the micro-Sn electrode to demonstrate high reversible sodiation capacity of 676–470 mAh g−1 with much improved capacity retention over 100 cycles.

著者

Junji SUZUKI Narumi KUBOTA Yukikazu OMURA Keisuke SUGATA Kento KISA Hiroaki SOFUJI Mayumi HATTORI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.3, pp.116-121, 2018-05-05 (Released:2018-05-05)

参考文献数

20

被引用文献数

1

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The development of SIB has attracted attention as a substitute for LIB. Low-temperature-fired soft carbon (LFSC) has been the target of study as SIB’s useful negative electrode material. We estimated Na chemical diffusion coefficient Dchem using the same approach and samples of previous report on LIB. The approach was potential step chronoamperometry (PSCA) method, and the samples were mesophase-pitch-based carbon fiber fired at four different low temperatures (600, 700, 800 and 950°C). The PSCA measurements by using a single LFSC fiber electrode were performed in an electrolyte of propylene carbonate (PC) containing 1 M NaClO4 at room temperature in a glove box filled with dried Ar. The largest Dchem value we obtained with four pristine LFSC was about 10−9 cm2/sec. The Dchem values depended not only on firing temperature of LFSC but also on the nature of LFSC’s surface. The effective surface treatment promoted Na insertion/extraction reaction rate on the carbon surface. The largest Na Dchem value we obtained after surface treatment was 10−8 cm2/sec. This Na Dchem value was close to the Li Dchem value (10−7.5 cm2/sec) by previous report, which suggests possibility of SIB’s practical use.

著者

Tadayoshi SAKATA Toshihito OHTAKE Masashi AZUMA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.4, pp.158-174, 2018-07-05 (Released:2018-07-05)

参考文献数

27

被引用文献数

2

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Quantum mechanical theory of electrochemical kinetics based on Fermi’s golden rule was formulated by introducing the concept of electron transfer distance. The expressions for the exchange current density and standard rate constant in electrochemistry were derived in analytical form, as well as exponential current overpotential dependence. The theory corresponds well to the electrode kinetics based on the transition state theory. It was applied to various kinds of electrode reactions to analyze the standard rate constants and the exchange current densities reported in past literature. The evaluated magnitudes of the electron exchange energy were very small, being in the order of 10−3 eV–10−5 eV. A new theory of transfer coefficient was constructed based on Debye-Hückel theory for electrolyte solutions could explain quantitatively the dependence of the transfer coefficient on the ionic strength of electrolyte solutions. It was demonstrated that the transfer coefficient represents electrostatic screening of the electrode potential by ions near the electrode and its magnitude was calculated quantitatively. Electron transfer distance was obtained by analyzing the dependence of the transfer coefficient on the ionic strength of electrolyte solutions. Our theory supported the ordinary electron transfer mechanism due to the overlap of wave functions between the electrode and redox species, denying tunneling mechanism.

著者

石川 正司

出版者

The Electrochemical Society of Japan

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.77, no.7, pp.538-542, 2009-07-05

被引用文献数

2

著者

Keisuke KIKUCHI Tomohiro YASUE Rie YAMASHITA Satoshi SAKURAGAWA Masao SUDOH Masayuki ITAGAKI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.10, pp.828-832, 2013-10-05 (Released:2013-10-05)

参考文献数

26

被引用文献数

4 14

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Large amounts of spent coffee grounds (SCGs) are generated all over the world. Since SCGs contain a lot of carbon and inherently has a porous structure, SCGs are considered to be a valuable industrial resource by carbonization. According to our previous research, it was apparent that the specific surface area of SCGs-derived carbon was greatly improved by potassium hydroxide (KOH) activation. In this research, we prepared an electric double layer capacitor (EDLC) using SCGs-derived carbon activated with KOH, and compared them to phenol resin-derived activated carbon (MSP-20, Kansai Coke and Chemicals Co., Ltd.), which is commonly used as a reference material in EDLC research. Electrodes were prepared by mixing 80 wt% activated carbon, 10 wt% carbon black and 10 wt% polytetrafluoroethylene (PTFE) and the electrolyte used was 1 M triethylmethylammonium-tetrafluoroborate (TEMA-BF4)/propylene carbonate (PC). The capacitive performance was evaluated by a constant current charge-discharge cycle measured with various electrical current loads from 5 to 150 mA/cm2. Although the capacitance of SCGs-derived carbon activated with KOH was inferior to that of MSP-20 at low current load density, it had high capacitance in high rate charge-discharge cycles. This suggests that the EDLC consisting of SCGs-derived activated carbon electrodes is superior to MSP-20 in capacitance retention rate when used at a high electric current density.

著者

Yutaro NORIKAWA Kouji YASUDA Toshiyuki NOHIRA

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.86, no.2, pp.99-103, 2018-04-05 (Released:2018-04-05)

参考文献数

31

被引用文献数

13

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The electrochemical behavior of Ti(III) ions in a eutectic KF–KCl molten salt was investigated using cyclic voltammetry, square wave voltammetry, and chronoamperometry at 923 K. Ti(III) ions were produced by the addition of 0.50 mol% of K2TiF6 and 0.33 mol% of Ti sponge to the melt. The reduction of Ti(III) ions to metallic Ti was observed as a single 3-electron wave around 0.33 V vs. K+/K in the square-wave voltammogram. The electrodeposition was conducted at a Mo electrode by galvanostatic electrolysis at −50 mA cm−2 for 20 min. The deposits were confirmed to be compact and adherent Ti metal films by scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction analysis. The oxidation of Ti(III) to Ti(IV) was observed at 1.82 V vs. K+/K as a reversible electrochemical process. The diffusion coefficient of Ti(III) ions was determined to be 3.9 × 10−5 cm2 s−1.

著者

松永 真理子

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.82, no.12, pp.1114-1115, 2014

著者

米澤 正智 雨宮 千夏

出版者

The Electrochemical Society of Japan

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.74, no.3, pp.240-244, 2006-03-05

参考文献数

32

著者

藤ヶ谷 剛彦 田中 泰彦 中嶋 直敏

出版者

The Electrochemical Society of Japan

雑誌

電気化学および工業物理化学 : denki kagaku (ISSN:13443542)

巻号頁・発行日

vol.78, no.1, pp.2-15, 2010-01-05

被引用文献数

4

---

One of the key issues in the utilization of carbon nanotubes (CNTs) for basic researches as well as their applications is to develop a methodology to solubilize/disperse them in solvents. In this review articles, we first summarize individual solubilization of single-walled carbon nanotubes (SWNTs) in solvents using surfactants, polycylcic aromatic molecules, DNA and condensed polymers. We then describe a novel method determining the electronic states of individually dissolved SWNTs having an own chirality index based on the analysis of Nernst equation. We also introduce our recent approach toward the fabrication of a novel catalyst for fuel cell that works at a nonhumid atmosphere using solubilized CNTs as material.