Controlled-synthesis and photocatalytic performance of micro/nano ZnO

Using zinc chloride and sodium hydroxide as the reactants, needle-, flower-, rod-and jujubestone-like ZnO micro-/nano-crystals were prepared via a low-temperature liquid phase method by controlling the composition of precursor solution. SEM, EDS, XRD, FT-IR, UV-Vis DRS and TG-DTA were used to characterize the products. Possible formation mechanism for these ZnO micro-/nanocrystals with different morphologies was discussed. The as-prepared ZnO powders were applied in photocatalytic degradation of methyl orange as model of organic pollutant during UV irradiation. The results show that the size and morphology of ZnO crystal are determined by its growth habit as well as nucleation and growth rates. A close relationship exists between the photocatalytic performance and the particle morphology and size. Rod-and jujubestone-like ZnO exhibit very strong photocatalytic activity, and methyl orange was completely degraded within 120 min.