Photocatalytic degradation of methyl orange using ZnO nanorods

Abstract

Nanosized ZnO rods were synthesized using a microwave-assisted aqueous method. High molecular weight polyvinyl alcohol was used as a stabilizing agent. Size, surface morphology, and structure were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). SEM and TEM images show that ZnO nanorods have diameters of about 50 nm and lengths of a few micrometers. The XRD pattern reveals that ZnO nanorods are of hexagonal wurtzite structure. The average crystallite size calculated from Scherrer's relation was found to be 40 nm. The effects of catalyst loading, pH value, and initial concentration of methyl orange on the photocatalytic degradation efficiency using ZnO nanorods as photocatalyst were discussed. The results revealed that ZnO nanorods with a diameter of 50 nm showed the highest photocatalytic activity at a surface density of 0.2 g dm⁻³.

Keywords:

• degradation
• methyl orange
• photocatalysis
• zinc oxide

Acknowledgments

One of the authors (KMG) thanks to UGC, New Delhi for providing the financial support under Major Research Project 37-335/2009(SR).