Photo-Induced Surface Reaction of Highly Oriented Anatase Polycrystalline Films Synthesized Using a CVD Apparatus Operated in Atmospheric Regime

Abstract

åCJú^»wCÍoujì»T^züAE»ô¸½»mõUN\ʽ cCñÞ Þ Ec³YÞ EåÎvÞ Þ EÖ¡GrÞ ÞHighrate growth of polycrystalline anatase lms was achieved on nonepitaxial substrates using a chemical vapordeposition technique operated under air atmosphere. As the growth rate of each crystalline face was strongly dependent on the deposition conditions, four types of anatase polycrystalline lms were fabricated with several oriented directions such asq112r , q110r , q100randq001r . The photoinduced surface reaction of the anatase lms was evaluated by the reduction ability of methylene blue under ultraviolet irradiation by an ultraviolet uorescent lamp. The reduction rate of methylene blue was found to be aected by the preferen tial growth direction of crystallites.

Fourier-Transform Infrared and Raman Spectroscopy of Pure and Doped TiO2 Photocatalysts

“…It thus appears that the photo-oxidation rate of carboxylates is highest on anatase particles in the size range 25-50 nm and is due to the smaller concentration of m-formate and bicarbonate species formed on these particles. The fundamental reason for their high activity is not known, but the discussion here and in the previous section strongly suggests that structure sensitive bonding and reactivity play important roles, qualitatively similar to what has been inferred for preferentially oriented TiO 2 thin films and facetted macrocrystals [142][143][144][145][146][147].…”

“…On anatase TiO 2 nanoparticles, there appears to be a correlation between the reactivity and the detailed morphology and surface structure [142][143][144][145][146]. T. Taguchi et al [147] recently reported that photocatalytic reduction of PtCl 6 2À in 2-propanol resulted in Pt deposition on (101) facets, while PbO 2 deposited on (112) facets upon photocatalytic reduction of Pb 2 þ in 2-propanol, suggesting that (101) facets provide reductive sites and (112) oxidative sites.…”

Epitaxial Growth of Magnesia Films on Single Crystalline Magnesia Substrates by Atmospheric-Pressure Chemical Vapor Deposition

“…For instance, the crystal morphology destabilizes; that is, continuous film surfaces roughen with increasing supersaturation (Tokita, Tanaka, & Ohshio, 2003;Tokita, Tanaka, & Saitoh, 2000). The surface and cross-sectional SEM images of the deposited films are shown in Figures 2 and 3.…”

“…Atmospheric-pressure chemical vapor deposition (CVD) is a method of depositing high-quality metal oxide films onto various substrates at atmospheric pressure and without requiring a vacuum system (Saitoh, Okada, & Ohshio, 2002;Saitoh, Takano, Kawaguchi, Washio, Ohshio, & Akasaka, 2009;Akasaka et al, 2013;Sugata et al, 2003;Satoh et al, 2002;Satou et al, 1999;Saitoh, Fukada, & Ohshio, 2003;Tokita, Tanaka, & Ohshio, 2003;Tokita, Tanaka, & Saitoh, 2000). Further, the atmospheric-pressure CVD apparatus is inexpensive and can be used to deposit uniform, homogeneous, dense films showing high coverage, tunable chemical compositions and morphologies, and no uncoated "hidden areas."…”

Synthesis of Strontium Oxide Whiskers with Preferential <111> Orientation by Atmospheric Chemical Vapor Deposition

“…In atmospheric CVD, metal-containing organic complexes are used as metal sources for oxide films. For examples, bis-magnesium acetylacetonate can be used as the Mg source for MgO films (Saitoh, Okada, & Ohshio, 2002) and titanium tetraisopropoxide (TTIP) can provide Ti for TiO 2 films (Tokita et al, 2003), using atmospheric CVD techniques. The atmospheric CVD setup is, fundamentally, a thermal CVD type.…”