Photocatalytic Properties of Aluminum Doped Zinc Oxide Nanocrystals Controlled Prepared via a Synergistic Ultrasonic/Hydrothermal Technique

Aluminum doped zinc oxide (ZAO) nanocrystals approximately 20 nm in diameter and with good dispersity and crystallinity were efficiently synthesized through a synergistic combination of ultrasonic and hydrothermal methods. The morphologies, structures, and optical properties of these nanocrystals, as well as the thernnochemistry of the precursor, were determined using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and thermogravimetric-differential thermal analysis (TG-DTA). ZAO nanocrystals were investigated with regard to the photocatalysis of rhodamine B (RhB) in solution, including studies of degradation rates and catalysis mechanism. It was found that both the particle size and crystallinity of the material can be controlled through the ultrasonic/hydrothermal synergetic effect. The main absorption peak of the product in a typical UV-Vis spectrum appeared at similar to 369 nm and its energy band gap was determined to be 3.36 eV. The ZAO produced by this method exhibits enhanced photocatalytic activity; compared to catalysis by materials produced solely by ultrasonic or hydrothermal routes, the degradation time of an RhB solution is reduced by 77.8%. In addition, it was found that this ZAO photocatalyst may be recycled and used more than once.