Large-Scale Fabrication of Sub-20-nm-Diameter ZnO Nanorod Arrays at Room Temperature and Their Photocatalytic Activity

We report a very simple and mild wet-chemical synthesis of ZnO nanorods to fabricate sub-20-nm-diameter ZnO nanorod arrays. These large-scale arrays could be obtained by immersing a Zn sheet in an ammonia aqueous solution containing Al 3+ ion at room temperature (25 °C) and normal atmospheric pressure (1 atm). This method uses little energy and requires no complex experimental procedures or equipment. The Zn ions were provided by the Zn sheet; as a consequence, the growth process is self-limiting. The ZnO nanorods produced were ∼250 nm long and ∼18 nm in diameter. On the basis of the results, we propose a mechanism for the growth of the ZnO structures on the Zn sheet with Al 3+ ion-containing ammonia aqueous solution. The high surface-to-volume ratio of the sub-20-nm-diameter ZnO nanorod arrays results in enhanced photocatalytic activity.