Tsukasa Torimoto 교수

Ionic liquids (ILs) including ambient-temperature molten salts, which exist in the liquid state even at room temperature, have a long research history. However, their applications were once limited because ILs were considered as highly moisture-sensitive solvents that should be handled in a glove box. After the first synthesis of moisture-stable ILs in 1992, their unique physicochemical properties became known in all scientific fields. ILs are composed solely of ions and exhibit several specific

Sputter deposition of gold (Au) onto ionic liquids (ILs) resulted in the formation of highly dispersed Au nanoparticles without additional chemical species, such as reducing and∕or stabilizing agents. The Au nanoparticles in 1-ethyl-3-methylimidazolium tetrafluoroborate had an average diameter (dav) of 5.5nm with a standard deviation (σ) of 0.86nm, while sputter deposition onto N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide resulted in the formation of much smaller Au nanopa

Nanoparticles of ZnS-AgInS2 solid solution (ZAIS) were synthesized by the thermal decomposition of (AgIn)xZn2(1-x)(S2CN(C2H5)2)4 precursors in a hot oleylamine solution. X-ray powder diffraction analyses revealed that the resulting nanoparticle powders were not a mixture of ZnS and AgInS2 but a ZnS-AgInS2 solid solution in which the fraction of ZnS was enlarged with a decrease in the value of x, that is, an increase in the content of Zn2+ in the precursors used. The energy gap of ZAIS nanopartic

Photodecomposition in aqueous solution of 3,5-dichloro-N-(3-methyl-1-butyn-3-yl)benzamide, whose popular name is propyzamide, was investigated using naked TiO2 and TiO2-loaded adsorbent supports as photocatalysts. The adsorbent supports used were zeolite (mordenite), silica, and activated carbon. The use of adsorbent supports was found to enhance the rate of mineralization of propyzamide and to reduce the concentration of solution-phase intermediates. The experimental results suggest that the ad

The simultaneous sputter deposition of gold and silver onto ionic liquids formed bimetallic alloy nanoparticles, which exhibited composition-sensitive surface plasmon resonance, the peak wavelength being red-shifted with an increase in the surface area of the gold foil targets sputtered.

Nanocomposite photocatalysts of CdS nanoparticles immobilized on Au core–SiO2 shell particles, in which the SiO2 layer acts as an insulator layer to prevent direct electron transfer from photoexcited CdS to Au particles, were prepared. The photocatalytic activity of CdS particles for H2 evolution was greatly dependent on the distance between CdS and Au particles, due to the locally enhanced electric field produced by photoexcitation of the localized surface plasmon resonance (LSPR) peak of Au pa

The photoluminescence intensity of ZnS-AgInS(2) solid solution nanoparticles was remarkably enhanced by increasing the heating temperature to 180 degrees C, above which the emission was simply diminished, while ZnS coating of the particles resulted in further enhancement of PL intensity, giving the highest quantum yield of ca. 80%.

Non-stoichiometric AgInS2 (AIS) semiconductor particles were synthesized by the thermal decomposition of single-source precursors in solutions of two kinds of primary amines (oleylamine and octylamine). The Ag content in the resulting nanoparticles was controlled by adjusting the chemical composition of the precursor used, in which the mole ratio of Ag+ to total metal ions was varied from 0.1 to 0.7, resulting in the production of non-stoichiometric AIS particles with varying amounts of Ag vacan

Positively charged CdS nanoparticles having diameter of 3.0 ± 0.2 nm were prepared by the chemical modification of their surfaces with thiocholine. Chains of size-quantized CdS nanoparticles were prepared by using the electrostatic interaction between positively charged nanoparticle surfaces and the phosphate groups of DNA molecules. The observation by transmission electron microscopy revealed that the CdS nanoparticles were arranged in a quasi one dimension with dense packing. The line width of

Over the past decade, many researchers have made efforts to develop high-quality I-III-VI2 group chalcopyrite-type semiconductor nanoparticles of Cu-based or Ag-based materials, such as CuInS2, Cu(InGa)Se2, and AgInS2, due to their low toxicity, wide range of absorption from UV to visible or near-infrared regions, and tunable energy gap depending on the chemical composition. Ag-based chalcopyrite-type nanoparticles have attracted much attention because they have physicochemical properties that c

Ultrasmall CdS nanoparticles were prepared by the size-selective photoetching technique. The smallest size of the CdS nanoparticles was obtained by the irradiation with the monochromatic light having the wavelength of 365 nm, while the absorbance of CdS nanoparticles monotonically decreased, for the whole wavelength, to null if the irradiation was performed using a wavelength less than 365 nm. The surface modification of CdS nanoparticles with thiophenol caused the red-shift of the absorption sp

The size-selective photoetching technique was used to control the size of a CdS nanoparticle inside a silica shell. With monochromatic light irradiation, the diffuse reflectance spectra of silica-coated CdS nanoparticles were blue-shifted, and the size of the resulting CdS nanoparticles incorporated in the silica shells was adjustable by varying the wavelength of irradiated light. TEM observation revealed that the original CdS nanoparticle seemed to be in close contact with the amorphous silica

Irradiation with a very high intensity laser pulse (355 nm) induces blue color in powders and films. The blue color, which is assigned to the formation of in the particle, persists in air for several months. With an increase of the concentration of in a given particle, photocatalytic activity is decreased because of a decrease in the thickness of the space‐charge layer as deep traps are populated.

Photoirradiation (lambda= 436 nm) of a deaerated 2-propanol aqueous solution containing nitrobenzene and rhodium-loaded silica-coated cadmium sulfide nanoparticles produced azoxybenzene with relatively high selectivity (68%), the photocatalytic activity being enhanced with a decrease in the size of the semiconductor particle core.