Nanowire Ordered Arrays for Electrochemical Sensing of H2O2

Abstract

Today, electrochemical sensors are considered very interesting in comparison to conventional techniques because they are very adaptable, cheap, have very low limit of detection and low detection time. The most used electrochemical technique is the amperometry . In amperometric sensors, a fixed potential is applied to the electrochemical cell, and a corresponding current, due to a reduction or oxidation reaction, is then obtained. This current it can be correlated with the bulk concentration of the detecting species (the solute) such as H2O2. Hydrogen peroxide is an essential mediator in food, pharmaceutical, clinical, industrial, and environmental analyses therefore, it is of great importance to detect H2O2. The key point in developing electrodes for detecting H2O2 is to decrease the oxidation/reduction overpotentials [1]. For this purpose it is essential to select the correct electrodic material. Among them the use of electrodes made of metals is very interesting because of their stability and durability. It is well known that platinum is the best electrodic material but, due to the very high cost of this precious metal, the attention was focused on the development of others cheaper metallic electrode. Here we have selected Pd and Cu because exhibit excellent catalytic behavior toward H2O2. To improve the electrochemical performance of these materials, we have fabricated these electrodes in nanostructured shape. In particular we have obtained regular and order array of Pd and Cu nanostructures with high structural regularity and tunability, well spatial orientation and arrangement. These morphological properties permit to take advantage of the high surface area and thus improve the performance of the sensors. Nanostructured arrays were obtained by a home-made procedure based on the displacement deposition reaction that allows to fabricate the electrodes without the use of an external power supply [2]. After synthesis, electrodes were tested for amperometric detection of hydrogen peroxide to find the sensor features. Here some preliminary results of the fabrication process and on the electrochemical tests were reported. [1] Y. Shao, J. Wang, H. Wu, J. Liu, I. A. Aksay, Y. Lina, Electroanalysis, 2010, 22, 1027-1036. [2] R. Inguanta, S. Piazza, C. Sunseri, Electrochemistry Communication, 2009,11, 1385-1388.