Size Effect of Silver Nanoparticle Melted into ZnO Nanorods for Photocatalytic Activity

Abstract

Ag/ZnO nanorod structure was synthesized by using the hydrothermal method to grow ZnO nanorods and melted silver nonoparticles into ZnO nanorods by thermal annealing process in vacuum at 700 oC. The photocatalytic activity for methylene blue decolorization is enhanced by silver nanoparticles melted into a ZnO nanorod structure owing to the formation of Schottky barrier near the Ag/ZnO interface prolongs the recombination of electron-hole pairs effectively. The size effect of silver nanoparticles in the Ag/ZnO nanorod structure for photocatalytic activity was discussed which was changed from 12 to 34 nm. The smaller silver nanoparticle size sample shows better decolorization efficiency of methylene blue solution owing to the higher surface area of Ag/ZnO nanoroad. Ag/ZnO nanorod films have been characterized by X-ray diffraction (XRD), UV-vis spectroscopy, field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The dye decolorization significantly increased from 69 to 99 % after UV light irradiation for 8 hr by the optimum Ag/ZnO nanorod film.