Photocatalytic Oxidation of Organic compounds: Self-Cleaning Surfaces
Contacts:
Su-Il In, Department of Physics, CINF-DTU, 4525-3150 (su-il.in@fysik.dtu.dk
Billie Abrams, Department of Physics, CINF-DTU, 4525-3113 (billie.abrams@fysik.dtu.dk)
Official supervisor: Ib Chorkendorff, Department of Physics, CINF-DTU, 4525-3170 (ibchork@fysik.dtu.dk)
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| TiO2 coated tiles stay clean resulting from the photooxidation of surface organics combined with water - in this case, rain (left). Indicator dyes can be used to assess the photoactivity of potential photocatalysts through a photoreduction process (right). |
Photocatalytic oxidation for environmental remediation is a promising route to complete mineralization of chemical pollutants in both water and air. The most utilized photocatalyst for these advanced oxidation processes (AOP) is TiO2 since it is inexpensive and non-toxic. However it has a large bandgap (~3-3.2eV) precluding its use with visible illumination. Many attempts have been made to shift the bandgap into the visible through doping with nitrogen or metals such as Fe, Pt, Ag and Au with limited success. Typically there is a trade-off between shifting the absorption into the visible and decreasing efficiency but this also depends on the type of photocatalytic reactions taking place.
Along these lines, the development of self-cleaning surfaces using thin film TiO2 as a photocatalyst has emerged from the Fujishima group in Japan. The concept of self-cleaning involves the coating of the TiO2 photocatalyst on surfaces such as tiles, floors, walls, hospital tables in an attempt to eliminate indoor and outdoor pollutants as well as bacterial infiltrations before large concentrations develop. Ultimately, new materials that are photoactive under visible light excitation are desirable.
This project consists of evaluating new potential photocatalyst materials for photooxidation of organic compounds. You will perform absorbance measurements on your samples and evaluate their activity using indicator dyes. There is the potential also for performing full scale photooxidation reaction in a batch process and measuring the products using gas chromatography (GC).