Advanced electrodes with nanostructured surfaces for electrochemical microsensors

Nanostructures have recently attracted great interest because of their unique properties and potential use in a broad range of technological applications. In the case of electrochemical microsensors, an array of nanostructures can be used to enlarge the surface area of sensing electrodes and it also has a positive impact on the redox reactions on their surfaces. It is assumed that these microsensors will then have higher sensitivity due to the surface modification. One of the easiest ways to modify an electrode surface by nanostructures is to deposit a metal into a thin nanoporous Al2O3 template which is placed on a gold electrode. Metal ions are attracted to the cathode (the gold electrode) during electrodeposition and fill the nanopores in the template. After completing the electrodeposition process, the template is dissolved and the metal nanostructures are obtained. Both nanorods and nanotubes of various wall-thicknesses can be created by this method. It has been found that the type of the nanostructure depends on specific electroplating,conditions (e.g. pH and concentration) and used template (i.e. diameters of the nanopores). Therefore, it is possible to control the type of the nanostructure by adjusting these electroplating parameters and to create either nanorods or nanotubes on purpose. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.