Surface modification of TiO2 by a ruthenium(II) polypyridyl complex via silyl-linkage for the sensitized photocatalytic degradation of carbon tetrachloride by visible irradiation

• Published in: Water research (Oxford) 2003-04, Vol.37 (8), p.1939-1947
• Main Authors: FUNG, Annie K. M, CHIU, Brenda K. W, LAM, Michael H. W
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon Tetrachloride - chemistry; Catalysis; Chemistry; Coloring Agents - chemistry; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; General and physical chemistry; General purification processes; Hydrogen-Ion Concentration; Oxidation-Reduction; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Pollution; Radiation; Ruthenium - chemistry; Titanium - chemistry; Wastewaters; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(02)00567-5

A new ruthenium(II) photosensitizer, [Ru(II)(py-pzH)(3)](2+) (where py-pzH=3-(2'-pyridyl)pyrazole), has been synthesized. The complex displayed outstanding excited state redox properties (estimated Ru(III)/Ru(II)* approximately -1.24 V vs. NHE) and was expected to sensitize the injection of electrons into the conduction band of anatase TiO(2) upon visible irradiation. The photosensitizer was anchored onto the surface of anatase TiO(2) particles via in situ silylation. The silyl-linkage displayed excellent stability in both aqueous media, over a wide pH range, and in common organic solvents. The resultant material, TiO(2)-[Ru(II)(py-pz-Si identical with )(3)], was found to be able to mediate degradation of CCl(4) in neutral aqueous medium under broad band visible irradiation (lambda>450 nm). The relation between the rate of degradation and concentration of substrate was explored and the mechanism of the photodegradation of the perhalogenated organic was discussed.