Papers by Author: Mitsuharu Fukaya

Abstract: Nanoscale TiO2 is widely used in consumer products like sunscreen and cosmetics. The establishment of damage evaluation test method was attempted to examine the potential neurotoxicity of nanoscale TiO2 to human body skin in vitro model. The emergence amounts of carbon dioxide, which was expected one of the generation products from the skin according to the titania photocatalyst nanoparticles activity under UV / visible light radiation, were identified and measured by the gas analyzer. It was found that it could evaluate the degrees of damage to skin with the photocatalysts activity by using the new evaluation test method considered.

Abstract: The influence of the titania photocatalyst particle of the nanometer region on the human being and biology’s to be doubted. Removing the uneasiness will expand further uses for the photocatalyst nanoparticle. Then, we attempted to examine the effect of several titania photocatalyst nanoparticles to the artificial skin like the human body under the UV and visible light irradiation conditions. The decomposition degree of the artificial skin was evaluated from the monitoring of the amount of carbon dioxide generated from them by the titania photocatalyst nanoparticle activity. Under the UV irradiation condition, it was almost found the carbon dioxide emergence from the artificial skin by the activity of the titania photocatalyst nanoparticle. On the other hand, under visible light condition it was mostly detected.

Abstract: The establishment of evaluation test method of the titania photocatalyst fine particle impact to human body skin was attempted. In this method, the amount of emergence of carbon dioxide, which was expected one of the generation products from the artificial skin according to the titania photocatalyst fine particles activity, was identified and measured by the gas analyzer. It was found that the amount of the carbon dioxide evolution from the artificial skin was different according to the difference of the particle size of the titania photocatalyst fine particle.

Abstract: Sick house syndrome caused by volatile organic compound (VOC) in the room is a serious problem in Japan. A photocatalytic wall paper was developed which is a wall paper coated with a visible light type of photocatalyst. When irradiated by light, the photocatalyst generates strong oxidative potential and decomposes almost all organic substances to water, carbon dioxide, and others. As a result of our experiment using the photocatalytic wall paper, toluene and acetaldehyde were decomposed efficiently even under a fluorescent lamp, and the photocatalytic wall paper had also strong anti-bacterial effect under the fluorescent lamp.

Abstract: Recently, the titania photocatalyst has been widely used in the environmental fields. However, because the past titania photocatalyst used only the range of ultraviolet rays, the usage has been limited. We attempted to develop a new type of titania photocatalyst that activates to respond not only in the ultraviolet rays region but also in the visible radiation region. The titania photocatalyst fine particles that zirconium oxide was uniformly added in the titania fine particles, and introduced simultaneously nitrogen into the crystal lattice in addition were synthesized. It was showed the high photo-absorption ability of the titania photocatalyst added the zirconium compared with not done by the absorption spectrum. Furthermore, it was found that the titania fine particles that introduced nitrogen colored to yellow, had also the high photo-absorption ability in the visible range of 600nm to 400nm in addition to the range of ultraviolet rays. It was thought that this depended on the reason based on the difference of the amount of the nitrogen introduction in the titania that originated in the zirconium. Moreover, it was compared the stability maintenance for the titania introduced nitrogen with it not done by the bleaching test of heating. As a result, the stability of the titania added the zirconium was higher than not added.