Masahiro Miyauchi 교수

Thin films of various metal oxides were prepared on glass substrates by a wet process to determine their photocatalytic ability to decompose adsorbed dye and to evaluate their photoinduced hydrophilicity under UV illumination. The metal oxides used in this study are classified into four categories based on their behavior over the two photochemical reaction: (1) active in both photocatalytic oxidation and photoinduced hydrophilicity (TiO2, SnO2, ZnO); (2) only active in photocatalytic oxidation (

Yellow SrTiO3 powders codoped with nitrogen and lanthanum (STO:N,La) were studied as visible light photocatalysts. The crystal phase of STO:N,La exhibited a pure perovskite phase, and O and Sr sites atoms were substitutionally doped with N and La atoms, respectively. The first principle calculation of STO:N,La indicated that the edge of the N(2p) band is situated above the valence band, which consisted of O(2p) orbitals, and the La orbitals did not exist in the band gap of SrTiO3. STO:N,La exhib

Nitrogen doped TiO2 films were fabricated by annealing anatase TiO2 films in gaseous NH3. Nitrogen atoms in these films were substitutionaly introduced into oxygen sites of TiO2 lattice. We have evaluated the zeta potential of these films and have found that it became negative with the amount of nitrogen doping. The photocatalytic decomposition of gaseous 2-propanol was examined under light-limited conditions, and the quantum yield (QY) was estimated while illuminating with ultraviolet (UV) and

We have evaluated photocatalytic oxidation activities and photoinduced hydrophilicities for TiO2 and SrTiO3 films. Although both types of films had almost the same photocatalytic oxidation activity, the reaction of photoinduced hydrophilicity was proceeding only on TiO2. The photoinduced hydrophilicity peculiar to TiO2 is not caused by the photocatalytic oxidation of organic compounds adsorbed on the surface, but is based on a surface structural change which is favorable for dissociative water a

Super-hydrophilic titanium oxide films show excellent potential as anti-fogging and self-cleaning surfaces; however, until now these properties have been limited to outdoor applications, since the high wettability condition requires sunlight-intensity UV radiation. Here is reported a novel TiO2/WO3 film (see Figure) that exhibits such a hydrophilic conversion even under regular indoor lighting.

Photocatalytic degradation of organic compounds requires photoexcited holes with strong oxidative power in the valence band (VB) of semiconductors. Although numerous types of doped semiconductors, such as nitrogen-doped TiO2, have been studied as visible-light-sensitive photocatalysts, the quantum yields of these materials were very low because of the limited oxidation power of holes in the nitrogen level above the VB. Recently, we developed visible-light-sensitive Cu(II) and Fe(III) nanocluster

The photoinduced hydrophilicity of TiO2 films with underlying WO3 layers (TiO2/WO3 layered thin film) was evaluated. Although the top surface was fully covered by TiO2, the presence of the WO3 layer enhanced the hydrophilic conversion rate under a 10-W cylindrical fluorescent light bulb. When the TiO2 and WO3 layers were separated by an insulating layer, the surface did not become highly hydrophilic under the same light bulb. On a TiO2/WO3 layered film the photocatalytic oxidation of methylene b

The photocatalytic oxidation and photoinduced hydrophilicity of thin tungsten trioxide (WO(3)) films coupled with platinum (Pt) nanoparticles were investigated. WO(3) films with underlying Pt nanoparticles (WO(3)/Pt/substrate) and those with overlying Pt nanoparticles (Pt/WO(3)/substrate) were synthesized by sputtering and sol-gel methods. Between these films, underlying Pt nanoparticles greatly enhanced the photocatalytic oxidation activity of WO(3) without decreasing the photoinduced hydrophil

Single crystalline zinc stannate (Zn(2)SnO(4) and ZnSnO(3)) nanoparticles were synthesized by a simple one-step hydrothermal reaction with a high production yield. Zn(2)SnO(4) is a (111) face-exposed octahedron, whereas ZnSnO(3) is a (100) face-exposed hexahedron structure. In particular, Zn(2)SnO(4) exhibits an efficient performance for applications in dye-sensitized solar cells.

We have fabricated an efficient visible-light-sensitive Cu(2+)-grafted Ce-doped ZnO photocatalyst (Cu(2+)-Ce(x)Zn(1-x)O) by adopting a metal ion doping and co-catalyst modification. Impurity states were formed below the conduction band (CB) edge in Ce(x)Zn(1-x)O, and these impurity states induce the visible-light absorption. Ce(x)Zn(1-x)O without a Cu(2+)-co-catalyst showed negligible visible-light activity due to the low reduction power of electrons in impurity levels. Surprisingly, Cu(2+)-modi

A copper-and-zinc (Cu–Zn) alloy material was synthesized using a vacuum sealing method, in which evaporated zinc was reacted with copper film or nanoparticles to form a homogeneous Cu–Zn alloy.

Highly aligned WO3 nanotrees are grown on metal tungsten by a simple hydrothermal reaction. Pd nanoparticles are selectively deposited on the WO3 nanotrees by a photocatalytic reduction reaction. Photocatalytic oxidation activity depends strongly on the position of the deposited Pd nanoparticles, and the WO3 nanotrees with Pd nanoparticles deposited at the bottom position exhibited efficient super-hydrophilicity. Detailed facts of importance to specialist readers are published as ”Supporting Inf

A visible-light-sensitive tin sulfide photocatalyst was designed based on a ubiquitous element strategy and density functional theory (DFT) calculations. Computational analysis suggested that tin monosulfide (SnS) would be more efficient than SnS2 as a photocathode for hydrogen production because of the low ionization potential and weak ionic character of SnS. To test this experimentally, nanoparticles of SnS were loaded onto a mesoporous electrode using a wet chemical method, and the bandgap of