Chair for Multicomponent Materials

Photocatalytic activity evaluation at the nanoscale: Aqueous and non-aqueous photocatalytic degradation

We conducted two different analytical approaches to investigate the photocatalytic performance heterogenous photocatalyst: (i) the decolorization of MB aqueous solution in the presence of TiO2 thin film (in-solution) and (ii) bleaching of methylene blue (MB) solid layer on photocatalytic TiO2 thin film (in-air). While the former approach is the most widely preferred, we have shown that the second one allows understanding surface specific photocatalytic reactions (both reversible and irreversible reactions).

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Fig 1. (a) Transmission spectrum (at 580 nm) recorded during a UV-on-off single cycle and (b) Schematic presentation of photocatalytic reaction steps within a UV-on-off single cycle (Step 1: UV light is off and no bleaching takes place, Step 2: UV light is on and it induces both reversible (light blue layer) and irreversible bleaching (dark blue), Step 3: UV light is off and reversible bleaching is over after 2 min of light off (color of the light blue layer is recovered) but the irreversible bleaching leads to the decolorization (top layer).

 

Selected publications

M.Z. Ghori, S. Veziroglu, B. Henkel, A. Vahl, O. Polonskyi, T. Strunskus, F. Faupel, O.C. Aktas, A comparative study of photocatalysis on highly active columnar TiO2 nanostructures in-air and in-solution, Sol. Energy Mater. Sol. Cells. 178 (2018) 170–178