Electrochemical Growth of Silver Nanobelts in Cylindrical Alumina Nanochannels

It is best-known in the nanoscience community that anodic aluminum oxide (AAO) membrane templates have been widely employed in the synthesis of one-dimensional nanomaterials, such as nanowires, nanorods, and nanotubes with cylindrical shapes. In this work, however, we demonstrate that AAO nanochannels can be used to grow silver nanobelts with rectangular shape. The growth method involved an electrochemical reduction of the Tollen’s reagent ([Ag(NH3)2]+) in aqueous solution at room temperature. We found that the concentration of the reagents (Ag2O and ammonia) and the magnitude of the reduction potential were critical to the growth of silver nanobelts. Significantly, we were able to tailor the dimensions of silver nanobelts. The lengths of silver nanobelts were controllable by the charge transported in the electrochemical reduction, the widths were confined by the diameter of nanochannels, and the thicknesses were dependent on the concentration of ammonia. In addition, crystallographic characterization indicates that silver nanobelts were single crystalline.