A green process for coupling manganese oxides with titanium(IV) dioxide.

MnO(2) nanoparticle-loaded TiO(2) prepared by a green process capable of removing harmful MnO(4)(-) ions from water exhibits catalytic activity for a test reaction, H(2)O(2) decomposition, in the dark with its activity enhanced by UV light irradiation.

Electrochemically assisted visible light photocatalysis in a heterosupramolecular system consisting of alpha-Fe2O3 and surfactant molecular assembly.

The synergy of an anodic-biased alpha-Fe2O3 film and a cationic surfactant molecular assembly leads to a high visible light induced activity for 2-naphthol oxidation and high stability. An abrupt increase in the photocatalytic activity at a surfactant concentration of ca. 0.2 mmol dm(-3) results from the adsolubilization of 2-naphthol into the hydrophobic nanospace of the surfactant bilayer formed on the alpha-Fe2O3 surface. Also, the surfactant bilayer provides sustainable photocurrent during the reaction.

Dispersion stability of TiO2 nanoparticles covered with SiOx monolayers in water.

The repetition of a two-step route consisting of chemisorption of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and its subsequent photooxidation has formed SiOx monolayers on the surfaces of TiO2 particles layer by layer (SiOx(n < or = 4)/TiO2, n = repeated number). The trace of these processes using diffuse reflectance FT-IR and solid-state 29Si NMR spectroscopy reveals that TMCTS is chemisorbed on TiO2 through Ti-O-Si bonds followed by growth of Si-O-Si networks via dehydration-condensation of the Si-OH groups generated by TiO2 photocatalytic oxidation of the Si-H and Si-CH3 groups. The point of zero charge of the TiO2 particles decreases from 6.5 to 5.4 at n = 1, reaching 4.9 at n2. As a result of coverage with the SiOx monolayers, the dispersion stability of TiO2 particles in neutral water is significantly improved without changing their optical properties. The dispersion stability further increases with accumulation of SiOx monolayers.

Ag(core)-AgCl(shell) standard microelectrode-loaded TiO2.

Micrometer-sized Ag(core)-AgCl(shell) composite crystals have been formed on TiO2 thin films by a two-st epelectrochemical method to provide information on the thermodynamic condition for efficient photoinduced interfacial electron transfer.

Color properties of gold-silver alternate nanowires electrochemically grown in the pores of aluminum anodic oxidation film.

Repeated electrodeposition of gold and silver on anodized aluminum plate yielded Au-Ag alternate nanowires in the geometrically anisotropic pores of the anodic oxidation films with mean diameter 10 nm and depth 10 mum, respectively. The absorption maximum wavelengths in the visible region resulting from the transverse surface plasmon resonances of Au and Ag nanorods are invariant with their growth. Consequently, the color of the anodized aluminum was simply tuned in a wide range, which is impossible to attain in each monometallic system.

Visible light photocatalytic decomposition of 2-naphthol by anodic-biased alpha-Fe2O3 film.

Transparent alpha-Fe2O3 films with varying film thickness were formed on a SnO2 transparent conducting film-coated glass substrate by metal organic deposition. Under anodic-biased conditions, the alpha-Fe2O3 film showed a high photocatalytic activity for the decomposition of 2-NAP with visible light irradiation. The alpha-Fe2O3 is transformed to inactive hydroxide as the reaction proceeds, while the activity of alpha-Fe2O3 is almost maintained in acetonitrile.

Electron transfer behavior and water photodecomposition ability of calcined material from a cerium-S-phenylene-O-holmium-O-phenylene-S hybrid copolymer.

Calcination of a cerium-S-phenylene-O-holmium-O-phenylene-S hybrid copolymer under a vacuum gave cerium oxide-carbon cluster-holmium oxide composite material. The material calcined at 600 degrees C loaded with Pt particles could decompose water to H2 and O2 with a H2/O2 ratio of 2 under visible light irradiation. ESR spectral examinations of the calcined materials revealed the possibility of a two-step electron transfer in the process of CeO2 --> carbon cluster --> Ho2O3 --> Pt with an oxidation site at CeO2 particles and a reduction site at Pt particles.

Photoinduced dissolution and redeposition of Au nanoparticles supported on TiO2.

Au particles (mean size ca. 3 nm) supported on TiO(2) particles were irradiated by UV light (>300 nm) in aqueous solutions at 278 K. Photo-induced dissolution of Au nanoparticles followed by redeposition occurred in aqueous solutions containing halogen ions. The dissolution of Au nanoparticles yielded a Au(III) complex with a halogen ion; subsequent reduction of the Au(III) complex caused precipitation of larger Au particles on TiO(2).

Photocatalytic activity of rutile-anatase coupled TiO2 particles prepared by a dissolution-reprecipitation method.

Rutile TiO(2) particles were partly dissolved into aqueous solutions of H(2)SO(4), and the Ti(4+) ions were reprecipitated by adding NH(3) aq. Rutile-anatase coupled TiO(2) particles were prepared by heating the solid recovered after centrifugation of the suspension. The content of anatase (c(A), wt%) could be controlled arbitrarily by changing the dissolved amount of rutile. The photocatalytic activity for the gas-phase oxidation of acetaldehyde was evaluated. The first-order rate constant, k, strongly depended on both c(A) and heating temperature (T(c)), increasing with an increase in T(c) at T(c)