High photocatalytic property and crystal growth of spindle-like ZnO microparticles synthesized by one-step hydrothermal method

The spindle-like ZnO microparticles were successfully synthesized by a simple hydrothermal method using triethanolamine (TEA) as the surfactant. The phase components, particle sizes and morphologies of ZnO samples derived from different contents of TEA (3, 4, 5, 6 and 7 mL) were characterized by XRD, SEM, TEM, EDS and BET. The photocatalytic activity of ZnO microparticles with different morphologies was evaluated by degradation of methyl orange (MO). The photocatalytic degradation process was monitored in terms of decolorization and total organic carbon (TOC) removals. The results indicated that the spindle-like ZnO exhibited higher photodegradation efficiencies under UV light irradiation than other ZnO structures due to the special morphology. The photodegradation could be described as the pseudo-first-order kinetics with apparent rate constants ranging from 3.59 × 10−3 to 1.04 × 10−2 min−1, which were based on the morphology of the structures. The sample presented a good recycle performance.