A facile salicylic acid assisted hydrothermal synthesis of different flower-like ZnO hierarchical architectures with optical and concentration-dependent photocatalytic properties

Different flower-like ZnO hierarchical architectures with wurtzite structure have been prepared by a facile salicylic acid (SA) assisted hydrothermal method, especially four flower-like ZnO nanostructures can be obtained simultaneously by using 18.00 mmol of SA. The petals of the flower-like ZnO architectures are mainly assembled by many of single nanorods, a mixture of single nanorods and bundle (cluster) of nanorods, or bundle of nanorods respectively. The nanorod exhibits the taper-like, hexagonal prism-like, tower-like or bamboo shoot-shaped body and the pyramid-like or pencil-like tip. Photoluminescence (PL) study shows two tunable wavelengths (542 nm and 565 nm). All the samples exhibit the similar Raman spectra. With increasing the amount of SA, the peak at 441 cm− 1 increases. The photodegradation rates of MB are more effective than these of MO, and the sample from 22.50 mmol of SA decomposes 55% of MB within 140 min. The activity of photocatalysts is significantly affected by the concentration of SA. With the increase of SA, the number of nanorods of the flower-like ZnO nanostructures increases, and leads to the improvement of photocurrent response and photocatalytic performance.