Jun Nunoshige

Metal ion and N co-doped TiO 2 as a visible-light photocatalyst

Powders of TiO2 doped with a metal ion and N species were prepared by a polymerized complex method and the visible-light photocatalytic activities of the products are investigated. Of the metal ions studied (K+, Ca2+, Sr2+, Ba2+, Nb5+, Fe3+, Zn2+, and Al3+), the photocatalyst prepared with Sr2+ exhibits the highest activity for acetaldehyde decomposition under visible-light irradiation. Results obtained from x-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analyses suggest that the doped N species reside at interstitial lattice positions in the catalyst. It was also found by XPS and ESR measurements that the doped N species combine with lattice oxygen to give rise to a paramagnetic property. The visible-light response of the catalyst is driven by the formation of paramagnetic N species at interstitial positions in the TiO2 lattice.

Unusual enhancement of H2 evolution by Ru on TaON photocatalyst under visible light irradiation

H2 evolution on TaON photocatalyst under visible light irradiation (420 nm < or = lambda < or = 500 nm) in an aqueous methanol solution is found to be remarkably enhanced by adding Ru as a noble-metal co-catalyst.

Molecular Weight Control of Thermosetting Poly(phenylene ether) Copolymer Produced by Heterogeneous Oxidative Coupling Polymerization

An efficient synthetic method to control the molecular weights of poly(phenylene ether) copolymer (Allyl-PPE) with a narrow molecular weight distribution (MWD) by oxidative coupling polymerization of 2,6-dimethylphenol (DMP) and 2-allyl-6-methylphenol (AMP) has been developed. This polymerization was carried out in the presence of the di-μ-hydroxo-bis[( N , N , N ′ , N ′ -tetramethylethylenediamine)copper(II)] chloride (Cu/TMEDA) catalyst in a water droplet/toluene heterogeneous system. The polymerization conditions such as the effects of the Cu/TMEDA concentration and the amount of water were investigated, and it was found that the molecular weight of Allyl-PPE could be easily controlled by changing the concentration of Cu/TMEDA aqueous solution.