Controlled synthesis and photocatalytic properties of three dimensional hierarchical ZnO microflowers

In this work, we report one pot facile hydrothermal synthesis of ZnO microflowers assembled through numerous nanosheets at low temperature. The microstructure and morphology of the as-obtained product can be tailored by altering growth parameters, such as reaction temperature, time, pH value and the type of zinc source. The possible growth mechanism for ZnO microflowers was proposed based on the experimental results. Photocatalytic tests demonstrate that the methyl orange (MO) dispersed in aqueous solution can be degraded over 95% after 90 min under UV light irradiation. In addition, the dyes of Congo red (CR) and methylene blue (MB) dispersed in aqueous solution degradation experiments were also conducted under the same conditions, respectively. The ZnO microflowers exhibit excellent photocatalytic activities with a degradation efficiency of 97% for CR with 55 min of irradiation and 98% for MB with 40 min of irradiation. The as-prepared ZnO products may be a promising candidate for photocatalytic applications in waste water purification.