Entity

Time filter

Source Type

Onoda, Japan

Tokyo University of Science, Yamaguchi is a private university in San'yō-Onoda, Yamaguchi, Japan. The school was first established as a junior college in 1987. It became a four-year college in 1995. Wikipedia.


Zhang H.,Wuhan University of Science and Technology | Toshima N.,Tokyo University of Science, Yamaguchi | Toshima N.,Japan Science and Technology Agency
Catalysis Science and Technology | Year: 2013

Clean syntheses, based on the use of natural renewable reagents, in water solution under mild conditions, are highly desirable processes and often the catalytic step is a key factor for the successful application. Gold (Au) and Au-containing bimetallic and trimetallic nanoparticles (BNPs and TNPs) have been extensively investigated as the promising catalysts for the clean syntheses of gluconic acid, which is an important intermediate in the field of food industry and pharmaceutical applications, by glucose oxidation using atmospheric oxygen or hydrogen peroxide as an oxidant. With significant research efforts, a lot of new efficient catalytic systems, based on the peculiar properties of nanometric Au NPs, have been developed for aerobic glucose oxidation. In this minireview, we provide an overview of the recent development of Au-containing BNPs and TNPs for the improved catalytic performance toward glucose oxidation. This journal is © The Royal Society of Chemistry 2013. Source


Toshima N.,Tokyo University of Science, Yamaguchi
Macromolecular Symposia | Year: 2011

Here we applied metal nanoparticles as a dopant of liquid crystals. Since liquid crystal molecules are self-assembled, it is not so easy to disperse metal nanoparticles in liquid crystal media. We first prepared metal nanoparticles protected by liquid crystal molecules by reduction of metal ions in the presence of liquid crystal molecules. This liquid crystal molecule-protected metal nanoparticles can be easily dispersed in liquid crystal media to fabricate liquid crystal sol containing metal nanoparticles. A simple liquid crystal molecule, 4′-pentylbiphenyl-4-carbonitrile (abbreviated as 5CB) was used in the present experiments at first. 5CB sol containing metal nanoparticles could construct novel twisted nematic liquid crystal devices (TN-LCDs), which revealed the electrooptic properties depending on the kind of metal of nanoparticles. During the experiments we discovered that 5CB-protected metal nanoparticles could move in liquid crystal media by applying the voltage. This phenomenon is inconvenient for liquid crystal displays, especially those driven by a matrix of thin-film transistors (TFTs). In order to avoid this phenomenon, we prepared polymer-protected metal nanoparticles and applied them to liquid crystal devices, which provided good performance as the devices, i.e., low driving voltage, rapid response at low temperature, and so on. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Zhang H.,Wuhan University of Science and Technology | Toshima N.,Tokyo University of Science, Yamaguchi | Toshima N.,Japan Science and Technology Agency
Applied Catalysis A: General | Year: 2012

Catalytically highly active PVP-protected AgAu bimetallic nanoparticles (BNPs) less than 2 nm in diameter were fabricated by simultaneous physical mixture of aqueous dispersions of Au clusters with Ag+ ions. The prepared AgAu BNPs, the dispersion of which was stably kept for more than 2 months under ambient conditions, were characterized by UV-vis, ICP, HR-TEM, and EDS in HR-STEM. The prepared BNP colloidal catalysts possessed a high activity for aerobic glucose oxidation. The highest activity of 3.77 mol-glucose s -1 mol-metal-1 was observed for the BNPs prepared with Ag/Au atomic ratio of 2/8, which was more than two times higher than that of Au nanoparticles with nearly the same particle sizes. © 2012 Elsevier B.V. Source


Zhang H.,Wuhan University of Science and Technology | Toshima N.,Tokyo University of Science, Yamaguchi | Toshima N.,Japan Science and Technology Agency
Journal of Colloid and Interface Science | Year: 2013

Integration of 'green chemistry' principles into nanotechnology is one of the key issues in nanoscience research today. In this work, three series of Au/Pt bimetallic nanoparticles (BNPs) with a structure of Au-rich core/Pt-rich shell were prepared using simultaneous reduction with rapid injection of NaBH4, simultaneous reduction with dropwise addition of NaBH4, and simultaneous alcohol reduction. The effects of particle size, electronic structure and composition upon the catalytic activities for aerobic glucose oxidation of the BNPs were also investigated. Catalytically highly active PVP-protected Au/Pt BNPs of about 1.5nm in diameter were synthesized using simultaneous reduction with rapid injection of NaBH4. The prepared colloidal Au/Pt BNPs catalysts possessed a high and durable catalytic activity for aerobic glucose oxidation, which were stably kept for more than 2months under ambient conditions. The maximum activities normalized with Au content of the BNPs with Au/Pt atomic ratio of 4/6 were nearly 10 times higher than that of Au nanoparticles (NPs) with nearly the same particle size. The higher catalytic activity of the prepared Au/Pt BNPs than the Au NPs can be ascribed to the following two factors; (1) the small average diameter, usually about 1.5nm, and (2) the presence of negatively charged Au and Pt atoms due to electron donation from protecting polymer (PVP: poly(N-vinyl-2-pyrrolidone)) by electronic charge transfer effects upon catalytically active sites. In contrast, the Au/Pt BNPs, synthesized by alcohol reduction and dropwise addition of NaBH4 into the starting solution and having the large mean particle sizes, showed a low catalytic activity. © 2012 Elsevier Inc. Source


Toshima N.,Tokyo University of Science, Yamaguchi
Pure and Applied Chemistry | Year: 2013

Energy has emerged as a strategic priority not only in research but also in all aspects of human lives. Most worldwide problems could be solved if energy were plentiful. In order to solve the energy problem, the following methods could be applicable: the creation of electricity from renewable energy resources, increase in conversion efficiency from fossil fuels to electricity, recovery of electricity from exhaust heat energy, and reduction of energy consumption. Nanotechnologies have already shown good promise in addressing and offering solutions in these priority areas. Here, we have demonstrated the application of metal nanoparticles (NPs) to electrocatalysts for the polyelectrolyte fuel cell (increase in conversion efficiency) and to additives to form hybrids with organic thermoelectric materials of conducting polymers (recovery of energy from exhaust heat). Thus, Pt monometallic and AuPt bimetallic NPs were used for electrocatalysts with high performance, and Pt and Au NPs were applied to hybrid thermoelectric materials to fabricate hybrid films with increasing thermoelectric performance for conversion of the exhaust heat near room temperature. © 2013 IUPAC. Source

Discover hidden collaborations