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Superior Photostability and Photocatalytic Activity of ZnO Nanoparticles Coated with Ultrathin TiO 2 Layers through Atomic‐Layer Deposition
Author(s) -
Sridharan Kishore,
Jang Eunyong,
Park Young Min,
Park Tae Joo
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201502876
Subject(s) - photocatalysis , atomic layer deposition , materials science , photodegradation , nanoparticle , rhodamine b , coating , conformal coating , layer (electronics) , chemical engineering , deposition (geology) , nanotechnology , degradation (telecommunications) , semiconductor , catalysis , optoelectronics , chemistry , organic chemistry , paleontology , telecommunications , sediment , computer science , engineering , biology
Atomic‐layer deposition (ALD) is a thin‐film growth technology that allows for conformal growth of thin films with atomic‐level control over their thickness. Although ALD is successful in the semiconductor manufacturing industry, its feasibility for nanoparticle coating has been less explored. Herein, the ALD coating of TiO 2 layers on ZnO nanoparticles by employing a specialized rotary reactor is demonstrated. The photocatalytic activity and photostability of ZnO nanoparticles coated with TiO 2 layers by ALD and chemical methods were examined by the photodegradation of Rhodamine B dye under UV irradiation. Even though the photocatalytic activity of the presynthesized ZnO nanoparticles is higher than that of commercial P25 TiO 2 nanoparticles, their activity tends to decline due to severe photocorrosion. The chemically synthesized TiO 2 coating layer on ZnO resulted in severely declined photoactivity despite the improved photostability. However, ultrathin and conformal ALD TiO 2 coatings (≈0.75–1.5 nm) on ZnO improved its photostability without degradation of photocatalytic activity. Surprisingly, the photostability is comparable to that of pure TiO 2 , and the photocatalytic activity to that of pure ZnO.