%0 Journal Article
%T Generation of Free OHaq Radicals by Black Light Illumination of Degussa (Evonik) P25 TiO2 Aqueous Suspensions
%A Haidong Liao
%A Torbj£żrn Reitberger
%J Catalysts
%D 2013
%I MDPI AG
%R 10.3390/catal3020418
%X This work demonstrates how formation of strongly chemiluminescent 3-hydroxyphthalic hydrazide by hydroxylation of non-chemiluminescent phthalic hydrazide can be applied as a selective reaction probe to obtain information on authentic hydroxyl radical, i.e., £żOH aq, formation, in black light illuminated Degussa P25 TiO 2 aerated suspensions in the pH range from 3 to 11. The £żOH aq formation was found to be strongly pH dependent. At alkaline pH, the apparent quantum efficiency of £żOH aq formation was estimated to be at the ~10 £ż2 level whereas at acidic pH it was near zero. Addition of phosphate and fluoride ions substantially enhanced the £żOH aq production in the acidic pH range. It is suggested that £żOH aq-radical formation in TiO 2 photocatalysis can occur by oxidation of hydroxyl ions in the water layer adsorbed on TiO 2 surfaces.
%K photocatalysis
%K TiO2
%K £żOHaq radical
%K chemiluminescence
%U http://www.mdpi.com/2073-4344/3/2/418