Size-controllable fabrication of noble metal nanonets using a TiO2 template.

We present herein a simple template method for preparing noble metal nanonets with defined sizes. The template utilized is a TiO2 nanotube (NT) array prepared by anodic oxidation of a pure titanium sheet in an electrolyte solution containing sodium fluoride. Uniform NTs with defined sizes are obtained by controlling the anodic potential. Gold nanonets are prepared by electrodepositing gold onto the template and then dissolving the TiO2 template in a 0.2 M HF solution. The pore size of the gold nanonet is determined by the TiO2 NT hole size. The formation mechanism of the nanonet is elucidated from field-emission scanning electron microscopy and transmission electron microscopy. Although a lot of reports have been presented on the synthesis of nanostructure materials, no work has been reported on the template synthesis of gold nanonets. This paper gives a simple and universal way to prepare noble metal nanonets.