Optical, Photocatalytic and Magnetic Properties of ZnO Nanostructures Prepared by Thermal Decomposition

ZnO nanostructures have been fabricated by annealing zinc acetate dihydrate at different temperatures (Tan). Thermogravimetric analysis, and XRD and Raman studies indicate ZnO crystals formed at above 250 oC. An increase of Tan would enhance the XRD intensity and number of Raman modes characteristic of hexagonal ZnO. Below 700 oC, the samples are mainly nanorods with the diameters and lengths of 50 –100 nm and 250 – 500 nm, respectively. As Tan increases from 700 to 1,200 oC, nanorods transform to irregular particles with average sizes of 0.2 – 2 mm. This influences the intensity ratio of UV-to-visible emissions. Though all the samples exhibit diamagnetism, several samples with Tan = 500 – 700 oC have additionally weak ferromagnetic order. Assessing RhB photodegradation has demonstrated the Tan = 300 oC sample showing the best photocatalyticity.