Synthesis and photocatalytic performance of spongy ZnO microstructures

Spongy ZnO microstructures were synthesized via a facile hydrothermal method using zinc nitrate hexahydrate and oxalic acid as raw materials. The as-obtained ZnO were characterized by powder X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and transmission electron spectroscopy (TEM), respectively. The BET surface area and average pore size of the samples were determined by nitrogen adsorption-desorption analysis. Effects of precursor and hydrothermal temperature on the morphology and photocatalytic activity of the products were investigated. SEM and TEM analysis indicated that the as-obtained spongy ZnO microstructures consisted of a large amount of ZnO particles with the average size of about 100 to 150 nm. The photocatalytic activities of the spongy ZnO microstructures were evaluated by photodegradation of methylene blue (MB) under UV light radiation. The results indicated that the ZnO synthesized at 150 °C for 10 h showed the highest photocatalytic activity and the degradation ratio of MB reached 99.5 % for 60 min of UV light irradiation with the light intensity of 10 mW · cm^-2.