title: Rapid probing of photocatalytic activity on titania-based self-cleaning materials using 7-hydroxycoumarin fluorescent probe.
abstract: Self-cleaning materials are widely applied, but the available methods for determining their photocatalytic activity are time consuming. A simple analysis method was proposed to evaluate rapidly the photocatalytic activity of self-cleaning materials. This method is based on monitoring of a highly fluorescent product generated by the self-cleaning materials after illumination. Under UV irradiation, holes photo-induced on the surface of self-cleaning materials can oxidize water molecules (or hydroxide ions) adsorbed on the surface to produce hydroxyl radicals, which then quantitatively oxidize coumarin to highly fluorescent 7-hydroxycoumarin. It was observed that the fluorescence intensity of photo-generated 7-hydroxycoumarin at 456 nm (excited at 346 nm) linearly increased with irradiation time, and the fluorescence intensity at a given irradiation time was linearly proportional to the photocatalytic activity of self-cleaning materials. Consequently, the photocatalytic activity of self-cleaning materials was able to be probed simply by using this new method, which requires an analysis time of 40 min, being much less than 250 min required for a dye method.
authors.affiliation: Department of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luo-Yu Road, Hong-Shan Qu, Wuhan 430074, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Guan
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhu
authors.forename: Hehui
authors.initials: H
authors.lastname: Zhou
authors.forename: Heqing
authors.initials: H
authors.lastname: Tang
mesh_terms: D002384:Catalysis; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D004396:Coloring Agents / Q000737:chemistry; D003374:Coumarins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000494:pharmacology*; D010777:Photochemistry / Q000379:methods*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014468:Umbelliferones / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D003374:Coumarins; D005456:Fluorescent Dyes; D014468:Umbelliferones; C009495:titanium dioxide; C031477:7-hydroxycoumarin; C030123:coumarin; D014025:Titanium