研究者詳細 - 仁科　勇太

論文 - 仁科　勇太

分割表示 219 件中 81 - 100 件目／全件表示 >>

Simulating the redox potentials of unexplored phenazine derivatives as electron mediators for biofuel cells

Ryo Nakagawa, Yuta Nishina

JPhys Energy 3 ( 3 ) 2021年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IOP PUBLISHING LTD

In this research, we aimed to establish a guideline for designing electron mediators suitable for biofuel cells. A redox potential simulator was fabricated by combining density functional theory calculation and experiment, allowing us to select molecules with appropriate redox potentials efficiently. Previously, mediators have been developed depending on the trials and errors; thus, our strategy will speed up the development of biofuel cells with outstanding performances.

DOI： 10.1088/2515-7655/abebc8

Constructing monolithic sulfur cathodes with multifunctional N,P dual-doped carbon nanocages to achieve high-areal-capacity lithium-sulfur batteries

Lingyu Du, Xiongcan Deng, Xueyi Cheng, Liwei Liu, Qiang Wu, Lijun Yang, Xizhang Wang, Yuta Nishina, Zheng Hu

FlatChem 28 2021年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER

Despite the great progress achieved, lithium-sulfur (Li-S) batteries still suffer unsatisfactory performance at high sulfur loading (>5 mg cm−2), which results from the impeded kinetics in charge transfer and polysulfides conversion with increasing electrode thickness. Herein, we have constructed a high-sulfur-loading monolithic cathode by in-situ reducing graphene oxide (GO) in the aqueous solution with dispersed sulfur-filled N,P dual-doped carbon nanocages (NPCNC). The Li-S battery with the areal sulfur loading of 6 mg cm−2 exhibits a high areal capacity of 6.7 mAh cm−2 and a retention of 4.2 mAh cm−2 after 250 cycles. The excellent performance is attributed to the synergism of the facilitated charge transfer and alleviated polysulfide diffusion by the reduced GO-framed 3D network, and the suppressed shuttle and polarization effects by the confinement and electrocatalysis of NPCNC. In addition, the monolithic sulfur electrode is free from binder, conductive agent and current collector, much beneficial to gravimetric performance. This study demonstrates an efficient strategy to increase the areal performance of Li-S batteries.

DOI： 10.1016/j.flatc.2021.100253

A glutathione responsive nanoplatform made of reduced graphene oxide and MnO<inf>2</inf> nanoparticles for photothermal and chemodynamic combined therapy

Baojin Ma, Yuta Nishina, Alberto Bianco

Carbon 178 783 - 791 2021年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Based on the specific tumor microenvironment, characterized by an overproduction of H2O2 and a high glutathione (GSH) concentration, the cascade reactions of nanomaterials, capable of mediating GSH depletion and reactive oxygen species (ROS) generation, have become a popular strategy to increase cancer therapy efficiency. In this study, we exploited reduced graphene oxide (rGO), one of the most promising graphene-based materials, in combination with manganese dioxide nanoparticles (MnO2 NPs) to design a multifunctional nanoplatform (rGO@MnO2) for efficient photothermal/chemodynamic combined therapies. MnO2 NPs were anchored onto the surface of rGO nanosheets (rGO NSs). MnO2 NPs oxidize intracellular GSH, and the generated Mn2+ ions converted H2O2 into HO[rad] by Fenton reaction. Meanwhile, rGO NSs mediated photothermal therapy (PTT) could further kill cancer cells. High temperature caused by photothermal conversion increased Fenton reaction rate, which enhanced the efficiency of MnO2 NPs mediated chemodynamic therapy (CDT). Importantly, thanks to the enhanced cell uptake of MnO2 NPs favored by the delivery properties of rGO, rGO@MnO2 possessed higher lethality to cancer cells. The decrease in the nanomaterials’ effective dose would further improve biosecurity and reduce cost. Therefore, rGO@MnO2 have great potential in cancer therapy by exploiting the synergistic effect of PTT and photothermal/delivery effect enhanced CDT.

DOI： 10.1016/j.carbon.2021.03.065

High-sorption terpyridine-graphene oxide hybrid for the efficient removal of heavy metal ions from wastewater

Dawid Pakulski, Adam Gorczyński, Dawid Marcinkowski, Włodzimierz Czepa, Tomasz Chudziak, Samanta Witomska, Yuta Nishina, Violetta Patroniak, Artur Ciesielski, Paolo Samorì

Nanoscale 13 ( 23 ) 10490 - 10499 2021年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Pollution of wastewater with heavy metal-ions represents one of the most severe environmental problems associated with societal development. To overcome this issue, the design of new, highly efficient systems capable of removing such toxic species, hence to purify water, is of paramount importance for public health and environmental protection. In this work, novel sorption hybrid materials were developed to enable high-performance adsorption of heavy metal ions. Towards this end, graphene oxide (GO) exhibiting various C/O ratios has been functionalized with ad hoc receptors, i.e. terpyridine ligands. The maximum adsorption capacity of highly oxidized/terpyridine hybrids towards Ni(ii), Zn(ii) and Co(ii) was achieved at pH = 6 and 25 °C reaching values of 462, 421 and 336 mg g-1, respectively, being the highest reported in the literature for pristine GO and GO-based sorbents. Moreover, the uptake experiments showed that heavy metal ion adsorption on GO-Tpy and GOh-Tpy is strongly dependent on pH in the range from 2 to 10, as a result of the modulation of interactions at the supramolecular level. Moreover, the ionic strength was found to be independent of heavy metal ion adsorption on GO-Tpy and GOh-Tpy. Under ambient conditions, adsorption capacity values increase with the degree of oxidation of GO because dipolar oxygen units can both interact with heavy-metal ions via dipole-dipole and/or ionic interactions and enable bonding of more covalently anchored terpyridine units. Both adsorption isotherms and kinetics studies revealed that the uptake of the heavy metal ions occurs at a monolayer coverage, mostly controlled by the strong surface complexation with the oxygen of GO and nitrogen-containing groups of terpyridine. Furthermore, selectivity of the hybrid was confirmed by selective sorption of the above heavy metal ions from mixtures involving alkali (Na(i), K(i)) and alkaline Earth (Mg(ii), Ca(ii)) metal ions due to the chelating properties of the terpyridine subunits, as demonstrated with municipal drinking (tap) water samples. Our findings provide unambiguous evidence for the potential of chemical tailoring of GO-based materials with N-heterocyclic ligands as sorbent materials for highly efficient wastewater purification.

DOI： 10.1039/d1nr02255e

Fiber-crafted biofuel cell bracelet for wearable electronics

Sijie Yin, Xiaohan Liu, Tatsuya Kaji, Yuta Nishina, Takeo Miyake

Biosensors and Bioelectronics 179 2021年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER ADVANCED TECHNOLOGY

Wearable devices that generate power using sweat have garnered much attention in the field of skin electronics. These devices require high performance with a small volume and low production rate of sweat by living organisms. Here we demonstrate a high-power biofuel cell bracelet based on the lactate in human sweat. The biofuel cell was developed by using a lactate oxidase/osmium-based mediator/carbon nanotube fiber for lactate oxidation and a bilirubin oxidase/carbon nanotube fiber for oxygen reduction; the fibers were woven into a hydrophilic supportive textile for sweat storage. The storage textile was sandwiched between a hydrophobic textile for sweat absorption from the skin and a hydrophilic textile for water evaporation to improve sweat collection. The performance of the layered cell was 74 μW at 0.39 V in 20 mM artificial sweat lactate, and its performance was maintained at over 80% for 12 h. Furthermore, we demonstrated a series-connection between anode/cathode fibers by tying them up to wrap the bracelet-type biofuel cell on the wrist. The booster six-cell bracelet generated power at 2.0 V that is sufficient for operating digital wrist watches.

DOI： 10.1016/j.bios.2021.113107

Biodegradation of graphene materials catalyzed by human eosinophil peroxidase

Rajendra Kurapati, Cristina Martìn, Vincenzo Palermo, Yuta Nishina, Alberto Bianco

Faraday Discussions 227 189 - 203 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Understanding the biodegradability of graphene materials by the action of oxidative enzymes secreted by immune cells is essential for developing applicable biomedical products based on these materials. Herein, we demonstrate the biodegradation of graphene oxide (GO) by recombinant eosinophil peroxidase (EPO) enzyme extracted from human eosinophils in the presence of a low concentration of hydrogen peroxide and NaBr. We compared the degradation capability of the enzyme on three different GO samples containing different degrees of oxygen functional groups on their graphenic lattices. EPO succeeded in degrading the three tested GO samples within 90 h treatment. Raman spectroscopy and transmission electron microscopy analyses provided clear-cut evidence for the biodegradation of GO by EPO catalysis. Our results provide more insight into a better understanding of the biodegradation of graphene materials, helping the design of future biomedical products based on these carbon nanomaterials.

DOI： 10.1039/c9fd00094a

REDOX ACTIVITY OF GRAPHENE OXIDE ANALOGUES IN ORGANIC REACTIONS

Yuta Nishina

CARBON 175 606 - 606 2021年4月

High-density monolithic pellets of double-sided graphene fragments based on zeolite-templated carbon

Atsushi Gabe, Mohammed Ouzzine, Erin E. Taylor, Nicholas P. Stadie, Naoki Uchiyama, Tomomi Kanai, Yuta Nishina, Hideki Tanaka, Zheng Ze Pan, Takashi Kyotani, Hirotomo Nishihara

Journal of Materials Chemistry A 9 ( 12 ) 7503 - 7507 2021年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

High-density and highly porous graphene-based pellets that exhibit an anomalous gas densification property have been fabricated by using zeolite-templated carbon (ZTC) as the major component and reduced graphene oxide (rGO) as a pure carbon binder. The unique structure of each ZTC particle consists of double-sided graphene fragments connected in a periodic, three-dimensional framework. The graphene-like sheets of rGO strongly connect the ZTC particles upon hot-pressingviathe generation of a large amount of unpaired electron spins, yielding monolithic pellets with exceptional mechanical toughness. The uniaxial pressing applied to the isotropic ordered framework of ZTC during pelletization leads to unique anisotropic structures. The so-obtained pellets represent a high density packing of graphene nanofragments with high volumetric surface area that exhibits high volumetric H2storage at room temperature.

DOI： 10.1039/d0ta11625d

Enhanced photocatalytic activity and stability of TiO<inf>2</inf>/graphene oxide composites coatings by electrophoresis deposition

Sujun Guan, Liang Hao, Hiroyuki Yoshida, Takaomi Itoi, Yanling Cheng, Satoshi Seki, Yuta Nishina, Yun Lu

Materials Letters 286 2021年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER

To enhanced photocatalytic activity and stability of titania (TiO ) coatings, graphene oxide (GO) forms on the surface of TiO coatings is fabricated by electrophoretic deposition (EPD). The results show the effect of EPD time on the formed hydroxyl groups from GO is significant, especially the controllable amount of GO by adjusting EPD time. The change in surface morphology of the GO on TiO coatings is obvious, showing an increased amount of GO. Owing to the effect of charge transfer between TiO and GO, the TiO /GO composites coatings exhibit excellent and stable photocatalytic activity. Notably, the cycle result of the sample after ultrasonic cleaning every 10 min reveal that the combination of TiO and GO is satisfactory. 2 2 2 2 2 2

DOI： 10.1016/j.matlet.2020.129258

Electrochemical Production of Graphene Analogs from Various Graphite Materials

Masato Komoda, Yuta Nishina

CHEMISTRY LETTERS 50 ( 3 ) 503 - 509 2021年3月

記述言語：英語出版者・発行元：CHEMICAL SOC JAPAN

Oxidation of graphite is widely recognized as a promising method for large-scale production of graphene-like materials. Chemical oxidation of graphite has been developed for more than 100 years, while electrochemical oxidation has attracted attention over the last 10 years as a simple, safe, and controllable production method for graphene. This review summarizes the electrochemical production of graphene analogs focusing on the electrochemical conditions and form of starting graphite that affect the properties of the products. Electrochemical treatment of graphite by direct current has been applied to various graphite, such as HOPG, graphite rod, graphite foil, and powdered graphite, and generates deeply oxidized graphene materials. On the other hand, treatments with alternative current generate low oxygen content products. Therefore, the electrochemical treatment of graphite provides an option for the controlled production of graphene-like materials.

DOI： 10.1246/cl.200780

Light reflectance and photoelectron yield spectroscopy enable acceptor level measurement in p-type Ba<inf>1-x</inf>TiO<inf>3</inf>semiconductor

Saya Fujii, Jun Kano, Norihiro Oshime, Tohru Higuchi, Yuta Nishina, Tatsuo Fujii, Naoshi Ikeda, Hiromi Ota

Journal of Applied Physics 129 ( 8 ) 2021年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

We report the band structure of Ba-deficient BaTiO3 as a p-type semiconductor, studied by a combination of light reflectance and photoelectron yield spectroscopy. Two acceptor levels were observed at the tail of a valence band. As the quantity of Ba vacancies increased, the density of state of the two acceptor levels also increased. The levels of the conduction band minimum and the valence band maximum shifted far away from the vacuum level, but the bandgap seems to be independent of Ba deficient concentration. For classical semiconductors such as Si and GaAs, the observation of impurity levels is restricted to low temperatures (∼20 K) owing to their narrow bandgaps. Oxide semiconductors have now been demonstrated with wide bandgaps and acceptor levels, at normal operating temperatures, which could lead to new device designs in the future.

DOI： 10.1063/5.0033761

Exploring Structures and Dynamics of Molecular Assemblies: Ultrafast Time-Resolved Electron Diffraction Measurements

Masaki Hada, Yuta Nishina, Takashi Kato

Accounts of Chemical Research 54 ( 3 ) 731 - 743 2021年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

ConspectusMolecular assemblies have been widely applied to functional soft materials in a variety of fields. Liquid crystal is one of the representative molecular soft materials in which weak intermolecular interactions induce its dynamic molecular behavior under external stimuli, such as electric and magnetic fields, photoirradiation, and thermal treatment. It is important to understand molecular behavior and motion in the liquid-crystalline (LC) states at the picosecond level for further functionalization of liquid crystals and molecular assembled materials. For investigation of assembled structures of the materials on the nanometer scale, X-ray diffraction (XRD) measurements have been a powerful tool. Despite the dynamic nature of the assembled materials, however, time resolution of XRD is limited to millisecond due to the response speed of the detector, which hampered real-time observation of the dynamics of the molecular assembly. For further understanding of the dynamic behavior of functional molecules and improvement of performance for their applications, the insights of faster dynamics on the micro-, nano-, pico-, and even femtosecond time scales are required. In this context, the interdisciplinary approaches of the emerging fields of materials chemistry and ultrafast science will open up new aspects of molecular science and technology. These approaches may lead to more effective design of new functional materials, which enables us to control molecular behaviors and motions.The development of ultrashort pulsed X-ray and electron sources has resulted in the visualization of the key structural dynamics on the femto-to picosecond time scale not only in isolated molecules but also in assembled molecules, such as in the LC, crystal, and amorphous phases. We focus on ultrafast phenomena in molecular assemblies induced by photoexcitation. Ultrafast time-resolved electron diffraction measurements are sensitive to the molecular periodicity under photoexcitation, and thus the methodologies directly provide the ultrafast photoinduced molecular dynamic arrangements.In this Account, we describe ultrafast structural dynamics of molecules in the LC phases observed by time-resolved electron diffraction measurements. Photoinduced conformational changes of LC molecules is shown as the example, which is the first observation of LC molecule using time-resolved electron diffraction. It is important to understand the correlation between the conformational or configurational changes induced in a photoirradiated single molecule and the oriented collective motions of molecular assemblies induced by intermolecular interaction. We also show observation of collective motions of azobenzene LC molecules. The collective motions are initiated from photoreaction in a single molecule and are subsequently amplified by the steric interaction with its neighboring molecules.One remaining challenge is to create the platform of materials and sample preparations for time-resolved electron diffraction experiments, which can only be achieved by the interdisciplinary fusion of the fields of materials chemistry and ultrafast science. Time-resolved electron diffraction is a powerful tool for structural investigation of molecular materials with a dynamic nature, whose adaptability goes beyond that of more complex assemblies of carbon nanomaterials. This methodology will extend the possibility to investigate motions of a variety of molecular self-assemblies on a larger scale, for example, to understand responses of biomolecular assemblies and intermolecular chemical reactions.

DOI： 10.1021/acs.accounts.0c00576

Co and Ni assisted CdS@g-C<inf>3</inf>N<inf>4</inf> nanohybrid: A photocatalytic system for efficient hydrogen evolution reaction

Jamal Abdul Nasir, Noor Islam, Zia ur Rehman, Ian S. Butler, Akhtar Munir, Yuta Nishina

Materials Chemistry and Physics 259 2021年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

Although the green production of H through water splitting has prompted the search for solar energy harvesting materials, this still remains an ongoing challenge in the field. We report here a novel and cost-effective photocatalytic system, Co and Ni assisted CdS-NRs/g-C N nanohybrid, with the potential to significantly accelerate the solar-assisted water-splitting reaction. In this system, the co-catalysts (Co and Ni) are selectively incorporated as redox mediators to impart electrons and holes away from CdS-NRs/g-C N . As a result, an excellent H production rate of 11376 μmol g h , turnover number (TON) of 1945 (after 24 h), and external quantum yield (EQY) of 4.4% were obtained at 420 nm and under mild reaction conditions. In addition, when the reaction media was tested in the absence of co-catalysts, a notable decrease in activity was observed indicating the promising role of Ni and Co as cocatalysts. The process of redox shuttle proceeds without adding sacrificial reagents, and relies entirely on the employed cocatalysts to competently separate the oxidation and reduction steps. It is anticipated that this unique cocatalysts-supported nanohybrid can create a synergistic effect between the cocatalysts and the CdS-NRs/g-C N heterojunction, providing more active sites to the catalytic system for the subsequent water splitting redox reaction. The experimental results reveal that the selective and optimum use of dual cocatalysts can be a promising approach to trigger both the production of H and improve the stability of the photocatalytic system for overall water splitting. 2 3 4 3 4 2 3 4 2 −1 −1

DOI： 10.1016/j.matchemphys.2020.124140

Reaction between Graphene Oxide and Intracellular Glutathione Affects Cell Viability and Proliferation

Baojin Ma, Shi Guo, Yuta Nishina, Alberto Bianco

ACS Applied Materials and Interfaces 13 ( 3 ) 3528 - 3535 2021年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Graphene oxide (GO) is currently developed for biomedical applications as a promising nanoplatform for drug delivery, phototherapy, and biosensing. As a consequence, its safety and cytotoxicity issues have attracted extensive attention. It has been demonstrated that GO causes an increase of intracellular oxidative stress, likely leading to its cytotoxicity and inhibition of cell proliferation. Being one of the main reductive intracellular substances, glutathione (GSH) is vital in the regulation of the oxidative stress level to maintain normal cellular functions. In this study, we found that GSH could be oxidized to GSSG by GO, leading to the formation of reduced GO (rGO). GSH depletion affects the intracellular reductive/oxidative balance, provoking the increase of the reactive oxygen species level, sequentially inhibiting cell viability and proliferation. Therefore, the reaction between GO and GSH provides a new perspective to explain the origin of GO cytotoxicity.

DOI： 10.1021/acsami.0c17523

Pure electric and magnetic fields applied to reduced graphene oxide for defect repair and oxygen removal

Takeshi Miyata, Syun Gohda, Takashi Fujii, Hironobu Ono, Hibiki Itoh, Yuta Nishina, Keiichiro Kashimura

Carbon 171 10 - 15 2021年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The rapid repair of graphene oxide (GO) was demonstrated using a microwave cavity resonator that separates pure electric and magnetic fields from microwaves. Reduced graphene oxide (rGO), a high-quality graphene-like material, was obtained using our method. Raman spectroscopy of rGO after microwave treatment revealed that the D band intensity decreased as the temperature increased, while the G and G′ band intensities increased with increasing temperature. Furthermore, the cavity resonator provided better defect repair and oxygen removal from GO than conventional heating, and the microwave magnetic field yielded better quality rGO than the microwave electric field. Microwave heating removed surface impurities and repaired defects in GO more effectively than conventional heating, while suppressing graphitisation. These findings provide guidelines for the microwave-assisted reduction of GO for the fast and large-scale production of graphene.

DOI： 10.1016/j.carbon.2020.08.044

Adsorption enhancement of nitrogen gas by atomically heterogeneous nanospace of boron nitride

Jun Kimura, Takahiro Ohkubo, Yuta Nishina, Koki Urita, Yasushige Kuroda

RSC Advances 11 ( 2 ) 838 - 846 2020年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

In this study, porous boron nitride (p-BN) with hexagonal phase boron nitride (h-BN) pore walls was synthesized using high-temperature calcination. Negligible variation in pore-wall structure can be observed in powder X-ray diffraction (XRD) profiles and infrared (IR) spectra. However, a highly stable p-BN with a stable pore structure even at 973 K under the oxidative conditions is obtained when synthesized at higher than 1573 K under nitrogen gas flow. For p-BN, this stability is obtained by generating h-BN microcrystals. Nitrogen adsorption-desorption isotherms at 77 K provide type-IV features and typical adsorption-desorption hysteresis, which suggests micropore and mesopore formation. Moreover, adsorption-desorption isotherms of Ar at 87 K are measured and compared with those of nitrogen. The relative adsorbed amount of nitrogen (i.e., the amount of nitrogen normalized by that of Ar at each relative pressure or adsorption potential value) on p-BN is considerably larger than that on microporous carbon at low-pressure regions, which suggests the existence of strong adsorption sites on the p-BN surface. In fact, the relative number of adsorbed nitrogen molecules to that of Ar on p-BN is, at most, 150%-200% larger than that on microporous carbon for the same adsorption potential state. Furthermore, additional adsorption enhancement to nitrogen between P/P0 = 10-5 and 10-3 can be observed for p-BN treated at 1673 K, which suggests the uniformly adsorbed layer formation of nitrogen molecules in the vicinity of a basal planar surface. Thus, unlike typical nanoporous sp2 carbons, p-BN materials have the potential to enhance adsorption for certain gas species because of their unique surface state.

DOI： 10.1039/d0ra08437a

Sophisticated rGO synthesis and pre-lithiation unlocking full-cell lithium-ion battery high-rate performances

Benoît Denis Louis Campéon, Yumi Yoshikawa, Takashi Teranishi, Yuta Nishina

Electrochimica Acta 363 2020年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

For the application to portable devices and storage of renewable energies, high-performance lithium-ion batteries are in great demand. To this end, the development of high-performance electrode materials has been actively investigated. However, even if new materials exhibit high performance in a simple evaluation, namely half-cell tests, it is often impossible to obtain satisfactory performance with an actual battery (full cell). In this study, the structure of graphene analogs is modified in various ways to change crystallinity, disorder, oxygen content, electrical conductivity, and specific surface area. These graphene analogs are evaluated as negative electrodes for lithium-ion batteries, and we found reduced graphene oxide prepared by combination of chemical reduction and thermal treatment was the optimum. In addition, a full cell is fabricated by combining it with LiCoO modified with BaTiO , which is applicable to high-speed charge–discharge cathode material developed in our previous research. In general, pre-lithiation is performed for the anode when assembling full cells. In this study, we optimized a "direct pre-lithiation" method in which the electrode and lithium foil were in direct contact before assembling a full cell, and created a lithium-ion battery with an output of 293 Wh kg at 8,658 W kg . 2 3 −1 −1

DOI： 10.1016/j.electacta.2020.137257

Diazonium Electrografting vs. Physical Adsorption of Azure A at Carbon Nanotubes for Mediated Glucose Oxidation with FAD-GDH

Andrew J. Gross, Shunya Tanaka, Clara Colomies, Fabien Giroud, Yuta Nishina, Serge Cosnier, Seiya Tsujimura, Michael Holzinger

ChemElectroChem 7 ( 22 ) 4543 - 4549 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

The electrochemical reduction of aryldiazonium salts is a versatile and direct route to obtain robust covalently modified electrodes. We report here a comparative study of Azure A modified carbon nanotube electrodes prepared by diazonium electrografting and by physical adsorption for bioelectrocatalytic glucose oxidation with fungal FAD-glucose dehydrogenase from Aspergillus sp. The electrografted and adsorbed electrodes exhibited different reversible electroactivity consistent with polymer-type and monomer-type phenothiazine surface assemblies, respectively. The electrografted Azure A electrodes exhibited superior mediated bioelectrocatalysis compared to the adsorbed Azure A electrodes. A more than 10-fold higher catalytic current up to 2 mA cm at 0.2 V vs. Ag/AgCl together with a similarly low onset potential of −0.05 V vs. Ag/AgCl was observed at the electrografted electrodes. Faster estimated electron transfer kinetics and a +200 mV potential shift for the polymer-type redox couple vs. the adsorbed monomer-type couple underlines the favourable driving force for mediated electron transfer with the buried FAD active site for the diazonium-derived bioelectrode. −2

DOI： 10.1002/celc.202000953

Iron nanoparticle templates for constructing 3D graphene framework with enhanced performance in sodium-ion batteries 国際誌

Benoît D.L. Campéon, Chen Wang, Yuta Nishina

Nanoscale 12 ( 42 ) 21780 - 21787 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

This study examines the synthesis and electrochemical performance of three-dimensional graphene for Li-ion batteries and Na-ion batteries. The in situ formation of iron hydroxide nanoparticles (Fe(OH)x NPs) of various weights on the surface of graphene oxide, followed by thermal treatment at elevated temperature and washing using hydrochloric acid, furnished 3D graphene. The characterization studies confirmed the prevention of graphene layer stacking by over 90% compared with thermal treatment without Fe(OH)x. The electrochemical performance of the 3D graphene was evaluated as a counter electrode for lithium metal and sodium metal in a half-cell configuration. This material showed good performances with a charging capacity of 507 mA h g-1 at 372 mA g-1 in Li-ion batteries and 252 mA h g-1 at 100 mA g-1 in Na-ion batteries, which is 1.4 and 1.9 times higher, respectively, than the graphene prepared without Fe(OH)x templates.

DOI： 10.1039/d0nr05682k

Analyzing dynamic chemical states of palladium supported on graphene oxide by X-ray absorption fine structure under oxidative and reductive environments

Masahiro Kunisu, Jumpei Yahiro, Naoki Morimoto, Yuta Nishina

Chemistry Letters 49 ( 11 ) 1337 - 1340 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The chemical state of Pd supported on reduced graphene oxide (rGO) changed dynamically and sensitively between Pd0 and Pd2+ by switching atmosphere between H2 and O2. In contrast, Pd supported on graphene oxide (GO) did not show such dynamic redox properties. The catalytic activity in dehydrogenation and hydrogenation reactions also depended on the oxygen content of GO.

DOI： 10.1246/CL.200529

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