121st General Meeting of the KCS

Type Poster Presentation
Area Environmental Energy
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code ENVR.P-669
Subject Generation Mechanism of Mobile Hydroxyl Radical on UV-illuminated TiO2
Authors Jiyoung Hwang, Bupmo Kim1, Wooyul Kim*, Wonyong Chou1,*
Department of Chemical and Biological Engineering, Sookmyung Women's University, Korea
1Department of Chemical Engineering, Pohang University of Science and Technology, Korea
Abstract TiO2 as a photocatalyst is a widely investigated for very diverse applications. Despite intensive research efforts devoted to photocatalysis, the complete understanding of photocatalysis phenomenon and the mechanisms is still far away. In our previous study, we addressed an important and popular question of why anatase and rutile forms of titania exhibit different photocatalytic activities. The ability of anatase to generate mobile •OH was proposed as a previously unrecognized key factor that explains the common observation that anatase has higher photocatalytic activities than rutile for many photooxidative reactions. The origin of crystal phase-dependent generation of •OHf was unveiled by studying •OHf generation mechanism. In general, two proposed mechanisms for the •OHf generation with illuminated TiO2 can be envisaged: i) oxidative, where surface trapped holes (h+t) directly oxidize H2O to •OHf, and ii) reductive, where surface trapped electron (e-t) generate H2O2 from O2, that subsequently decomposes to yield •OHf. In any case, •OHf generation seems to be a crystal phase dependent process. To find out why rutile phase cannot generate •OHf, tetramethylammonium (TMA) as an indicator of mobile OH radical was proved in acidic condition. A complete assessment of the reductive pathway requires to clarify the role of H2O2 in the system, as it is a •OHf intermediate. The detail generation mechanism of mobile •OHf will be discussed.
E-mail wldud1765@gmail.com