Photocatalytic activity of ZnO- and TiO2-coated poly (methyl methacrylate) microcapsules by atomic layer deposition for water purification

Poly (methyl methacrylate) (PMMA) is a common everyday polymer material that can be used as a substrate to improve the performance of functional coatings. In this work, PMMA microcapsules (PMMA-MCs) are coated with photocatalytic metal-oxide thin films. A low temperature (100 degrees C) atomic layer deposition of ZnO and TiO2 on PMMA-MCs is described to form a three-dimensional structured composite. Scanning electron microscopy observations confirms that the ZnO and TiO2 thin films are conformal to the spherical surface of the PMMA-MCs substrates, creating a greater photocatalytic active surface area. The photocatalytic activity of the prepared ZnOand TiO2-PMMA-MCs composites towards the mineralization of methylene blue (MB), a model pollutant, are investigated. Under UV-VIS irradiation, the ZnO-PMMA-MCs are more efficient towards MB dye degradation. Therefore, the proposed preparation approach for core-shell structured composites is considered as a valid alternative to the conventional routes for the development of efficient supported photocatalysts in heat sensitive materials for water purification application.