Hydrothermal synthesis of mesostructured ZnO micropyramids with enhanced photocatalytic performance

Abstract

The present article reports the synthesis, characterization and photocatalytic performance of highly oriented three dimensional ZnO micropyramids obtained by the surfactant assisted precipitation- hydrothermal treatment. Pluronic P-123 triblock copolymer was the surfactant employed in the present synthesis. The synthesized ZnO material was characterized for its phase and morphological studies. X-ray diffraction patterns suggested the formation of pure hexagonal wurtzite phase with the mean crystalline size of 39nm. Electron microscopic studies of the material revealed the hexagonal micropyramid like morphology with an approximate size of 1–3μm and the ZnO was found to be single crystalline by the SAED analysis. The ZnO micropyramids provided a bimodal mesoporous texture with a low specific surface area (4.5m2/g). Optical properties investigated using the photoluminescence spectrum indicated that the ZnO has a broad UV and blue emission bands which were attributed due to the annihilation of excitons, and a broad visible green emission corresponds to the oxygen interstitial defects. Under the UV light illumination, several concentrations of methylene blue were degraded completely over the as-synthesized ZnO microcrystals for repeated cycles.