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

Abstract

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 18.00mmol 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 (542nm and 565nm). All the samples exhibit the similar Raman spectra. With increasing the amount of SA, the peak at 441cm−1 increases. The photodegradation rates of MB are more effective than these of MO, and the sample from 22.50mmol of SA decomposes 55% of MB within 140min. 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.