Simple and Low Temperature Method for Preparation of Nanocrystalline ZnO in Presence of [EMIM][EtSO4] and Their Photocatalytic Activities

Simple, low temperature and environmentally benign green route is proposed for preparation of nanocrystalline ZnO in presence of a low-cost and halide-free room-temperature ionic liquid (RTIL) by refluxing at 95 °C for 60 minutes. The X-ray diffraction (XRD) studies display that the products are well-crystallized in the form of wurtzite hexagonal. Morphology of the as-prepared ZnO was characterized by scanning electron microscopy (SEM) and the results demonstrate that the prepared nanocrystalline ZnO in presence of the RTIL is smaller than that of prepared in water. Energy dispersive X-ray spectroscopy (EDX) investigations reveal that the products are extremely pure. Diffuse reflectance spectra (DRS) of the prepared sample in the neat RTIL shows blue shift (0.33 eV) relative to the bulk ZnO that can be attributed to quantum confinement effect of nanocrystalline ZnO. Investigation of photocatalytic degradation of methylene blue (MB) on the prepared samples demonstrates that rate constant of the reaction increases with the RTIL content of the media.