Effect of annealing temperature on the properties and photocatalytic efficiencies of ZnO nanoparticles

This paper reports the effect of annealing temperature on the properties and photocatalytic efficiencies of ZnO nanoparticles prepared by facile solution combustion method using zinc nitrate as precursor and dextrose as fuel and oxidizer. The prepared ZnO nanoparticles were characterized by several techniques in terms of their morphological, structural, compositional and optical properties. The detailed characterizations confirmed that the prepared nanoparticles are pure ZnO possessing well-crystallinity and wurtzite hexagonal phase. Interestingly, it was observed that annealing temperature greatly influences particle size, morphology, band-gap and photocatalytic efficiencies on ZnO nanomaterials. Further, the prepared ZnO nanoparticles annealed at different temperatures were efficiently utilized for the photocatalytic degradation of a water soluble DR-23 dye and it was observed that the samples annealed at 400 °C, 500 °C, 700 °C, and 800 °C, the percentage photo degradation were 88.48%, 95.49%, 92.63% and 86.40%, respectively. However, the ZnO nanoparticles annealed at 600 °C exhibited almost complete photodegradation of the DR-23 dye. Moreover, all the samples follow a pseudo first order reaction kinetics.