Transparent Micrometer-Thick TiO2 Films on SiO2-Coated Glass Prepared by Repeated Dip-Coating/Calcination: Characteristics and Photocatalytic Activities for Removing Acetaldehyde
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- 作者：Nobuaki Negishi ; Sadao Matsuzawa ; Koji Takeuchi ; Pierre Pichat
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：July 24, 2007
- 年：2007
- 卷：19
- 期：15
- 页码：3808 - 3814
- 全文大小：407K
- 年卷期：v.19,no.15(July 24, 2007)
- ISSN：1520-5002
文摘
TiO2 films on silica-coated glass plates were obtained through dip-coating and subsequent calcinationat 753 K; this temperature and the proportions of the dip-coating solution components (tetraisopropylorthotitanate, ethoxyethoxyethanol, propan-2-ol, 
-terpineol, and a hydroxypropyl cellulose) wereoptimized. Depending on the number N (5 
N 30) of dip-coating/calcination procedures, the filmscharacteristics were hardness, >9 H; thickness, 0.9-5.4 
m; transmitted light, ca. 70% (visible spectralregion); absorbed light, 90-100% at 358 nm; surface area, 40-80 m2 g-1; pore volume 7-20 mL g-1;anatase particle size, 3.5-4 nm (elemental crystallites) and 12-16 nm (agglomerates). These tiny sizes,which did not increase for N 
20, were obtained because of the use of hydroxypropyl cellulose. Thephotocatalytic removal rate of acetaldehyde (3.25 ppmv) or toluene (1 ppmv) in flowing air (50% RH)showed that the TiO2 minimum amount varied with the pollutant and that a 1-2 m thickness wassufficient to achieve a near-maximum efficacy. In summary, this preparation produces anatase filmshaving the mechanical, optical, and photocatalytic properties required to obtain self-cleaning (water contactangle test) and air depolluting (at least in relatively confined spaces) glass without using a binder, whichcan restrict the accessibility to TiO2 and alter the photocatalytic activity.
-terpineol, and a hydroxypropyl cellulose) wereoptimized. Depending on the number N (5 N 30) of dip-coating/calcination procedures, the filmscharacteristics were hardness, >9 H; thickness, 0.9-5.4 m; transmitted light, ca. 70% (visible spectralregion); absorbed light, 90-100% at 358 nm; surface area, 40-80 m2 g-1; pore volume 7-20 mL g-1;anatase particle size, 3.5-4 nm (elemental crystallites) and 12-16 nm (agglomerates). These tiny sizes,which did not increase for N 20, were obtained because of the use of hydroxypropyl cellulose. Thephotocatalytic removal rate of acetaldehyde (3.25 ppmv) or toluene (1 ppmv) in flowing air (50% RH)showed that the TiO2 minimum amount varied with the pollutant and that a 1-2 m thickness wassufficient to achieve a near-maximum efficacy. In summary, this preparation produces anatase filmshaving the mechanical, optical, and photocatalytic properties required to obtain self-cleaning (water contactangle test) and air depolluting (at least in relatively confined spaces) glass without using a binder, whichcan restrict the accessibility to TiO2 and alter the photocatalytic activity.