Fabrication of morphology-controlled TiO_2 photocatalyst nanoparticles and improvement of photocatalytic activities by modification of Fe compounds

摘要

Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of Ti O2 nanoparticles. Site-selective deposition of metal or metal oxide on Ti O2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of Ti O2 nanoparticles under photoexcitation. A remarkable improvement of photocatalytic activity of shapecontrolled brookite and rutile Ti O2 nanorods with modification of Fe3compounds was observed under visible light.Crystal face-selective metal compound modification on exposed crystal faces of Ti O2 nanorods with brookite and rutile phases was successfully prepared. Brookite and rutile Ti O2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive Ti O2 photocatalysts because of the remarkable suppression of back electron transfer from Ti O2 to oxidized metal compounds on the surface of the Ti O2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled Ti O2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite Ti O2 nanorod, showing remarkably high activity for degradation of organic compounds compared with the photocatalytic activities of anatase fine particles(ST-01), is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite Ti O2 nanorods by crystal face-selective modification of Fe3compounds was also discussed in this paper. The Fe3compound-modified rutile and brookite Ti O2 nanorods show much higher activity than conventional visible-light responsive N-doped Ti O2, which is commercially available in Japan.