Affiliation: | a Department of Chemistry and Environmental Technology, Kinki University, Higashi-, Hiroshima 739-2116, Japan b Division of Interdisciplinary Sciences, Yamanashi University, 4-4-37 Takeda, Kofu 400-8510, Japan c Department of Chemistry, Aoyama Gakuin University, Setagaya-ku, Tokyo 157-8572, Japan d Ecodevice Co. Ltd., 3-26-2, Ryogoku, Sumida-ku, Tokyo 130-0026, Japan |
Abstract: | A visible-light (vis)-active titanium oxide photocatalyst was prepared by a simple wet process: the calcination of the hydrolysis product of Ti(SO4)2 with ammonia using an ordinary electric furnace in dry air at 400 °C. The color of this photocatalyst was vivid yellow and absorbed light in the blue (400 nm) to bluish-green (550 nm) region exclusively. Its structure was characterized to anatase with oxygen-deficient stoichiometry by XRD and X-ray photoelectron spectroscopy. Nitrogen was also detected, but only in trace amounts. Using blue-light-emitting diodes as a light source, 540 ppm of acetone was decomposed within 36 h and a stoichiometric yield of CO2 was obtained. From the results of the crystalline size D, it was found that vis-activity could be realized on polycrystalline particles and the grain-boundaries (GBs) are thought to be important, since oxygen vacancies are easily created in GBs, which could form a GB state. Finally, we concluded that oxygen-deficient sites formed in GBs are important to emerge vis-activity, and nitrogen doped in the part of oxygen-deficient sites are important as a blocker for reoxidation. |