Generation of Free OHaq radicals by Black Light Illumination of Degussa P25 TiO2 Aqueous Suspensions
2013 (English)In: Catalysts, ISSN 2073-4344, Vol. 3, no 2, 418-443 p.Article in journal (Refereed) Published
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., (OHaq)-O-center dot, formation, in black light illuminated Degussa P25 TiO2 aerated suspensions in the pH range from 3 to 11. The (OHaq)-O-center dot formation was found to be strongly pH dependent. At alkaline pH, the apparent quantum efficiency of (OHaq)-O-center dot formation was estimated to be at the similar to 10(-2) level whereas at acidic pH it was near zero. Addition of phosphate and fluoride ions substantially enhanced the (OHaq)-O-center dot production in the acidic pH range. It is suggested that (OHaq)-O-center dot-radical formation in TiO2 photocatalysis can occur by oxidation of hydroxyl ions in the water layer adsorbed on TiO2 surfaces.
Place, publisher, year, edition, pages
2013. Vol. 3, no 2, 418-443 p.
IdentifiersURN: urn:nbn:se:kth:diva-25347DOI: 10.3390/catal3020418ISI: 000339586600004ScopusID: 2-s2.0-84894599333OAI: oai:DiVA.org:kth-25347DiVA: diva2:357595
Updated from Manuscript to Article. QC 201503092010-10-192010-10-192015-03-09Bibliographically approved