Photochemical properties of CeO2-coated ZnO nanorods

Well-aligned ZnO nanorods were deposited by a mild hydrothermal process and coated with nanosized CeO2 particles (approximately 5 nm) by an oxidative-soak-coating method at 45 degrees C. The low growth temperature proved useful in avoiding interfacial reaction between the two phases. Correlation of photoluminescence results indicated that the defects responsible for the deep level emission (DLE) from ZnO were largely located at the surface. The CeO2 coating reduced the DLE but also the photocatalytic activity as surficial hydroxyl groups were involved in the nucleation of the CeO2 phase and thus not available for absorption of the methylene blue species for degradation. Still, CeO2 coated ZnO nanorods retained their photocatalytic ability and could be useful as bifunctional catalyst to treat multiple contaminants simultaneously.