Metal Nanoparticles/BDD Hybrid Electrodes for Analytical Detection of Pollutants in Water
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Metal Nanoparticles/BDD Hybrid Electrodes for Analytical Detection of Pollutants in Water Dounia K. Belghiti, Emmanuel Scorsone, Philippe Bergonzo CEA, LIST, Diamond Sensors Laboratory, 91191, Gif-sur-Yvette, France Abstract: Boron Doped Diamond (BDD) electrodes exhibit excellent properties including a wide potential window in aqueous media, high corrosion resistance, chemical inertness, bio-compatibility and low background current. In order to increase their selectivity for analytical applications, several studies were carried out recently on the possibility to deposit metal nanoparticles such as Pt or Ir on such BDD electrodes1,2,3,4. Indeed these nanoparticles bring interesting electro-catalytic properties to the electrodes, thus offering the possibility to address new analytes. Here an electrode array was developed, based on multiple BDD electrodes casted with various metal nanoparticles. The simultaneous detection of analytes by each electrode composing the array gives potentially a unique fingerprint to the analytes, thus increasing the specificity and the selectivity of the sensor. 1. Introduction In recent years, many studies have been conducted in order to develop new generations of electrochemical sensors that are capable of providing specific detection5,6. These technologies are often based on the combination of an array of nonspecific sensors6. Recording signals from non-selective sensors can be employed to extract of qualitative or quantitative chemical information. In order to produce such an array, metal electrodes based on metal eg. gold, platinum or iridium, as working electrodes are often used. Different sensitivity and selectivity patterns are obtained at each electrode. However, bare metal electrodes often diplay limited sensitivity, poor stability, narrow potential window and often may be expensive when precious metals are used2. To overcome these problems, several routes are investigated. One of them consists of depositing metal nanoparticles onto a second material which does not suffer from the above limitations. Moreover, it has been demonstrated that metal nanoparticles onto bare electrodes exhibit much higher electro-catalytic activity than the bulk material7,4. R. G. Compton et al8 showed that using nano-particles assemblies instead of macro-electrodes increase the sensitivity by approximatively a factor of five. Indeed, the nano-particles acted such as a microelectrode witch exhibited a high activity in comparison with macro-electrodes8. Nanoparticles were deposited for instance on glassy carbon electrodes9 or metal oxide films10. However, the use of materials such as glassy carbon may cause some problems in particular in terms of stability due to electrode fouling. In this work, Pt and Ir nanoparticles were deposited onto BDD electrodes. This choice is justified by the fact that BDD shows outstanding electrochemical properties such as a wide potential window in aqueous media, high corrosion resistance, low background current, and long term stability11,4,12. The nano-dots deposition invol
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