Nanostructured Carbon Metal Oxide Based Electrochemical Sensors

Abstract

An electrochemical (EC) sensor is a device that transforms chemical information of a target analyte, which can be DNA, proteins, small molecules like glucose, toxic gases or environmental carcinogens into an analytical useful signal. Due to its ability to monitor harmful pollutants on-site, the focus on EC sensing technology is growing exponentially. Moreover, EC sensors can be easily miniaturized for the mass-production of point-of-care devices. It is well known that the electrode materials especially functionalized nanomaterials or EC stable nanostructured materials play a crucial part in enhancing the EC sensor s selectivity and sensitivity. Designing of appropriate electrode materials and understanding their properties at the molecular level is therefore extremely important for the construction of high-performance EC sensing platforms. The utmost goal of this Ph.D. thesis is to synthesize nanostructured carbons and carbon functionalized metal oxides using both wet chemical and physical synthesis routes for EC sensing applications. The whole thesis is primarily divided into three parts. The first part comprises the design of carbon functionalized iron oxide nanoparticles, where the attached functional groups (hydroxyl, carboxyl) are acting as the anchor sites to adsorb target analytes. The second part focuses on the use of chemical vapor deposition technique for the production of conductive diamond nanostructures. Here, the role of dopants and non-diamond phases on the EC properties (wide potential window, low and stable background current, EC response of redox couple, etc.) of conductive diamonds have been discussed. Finally, we demonstrate a single-step approach for the production and patterning of a porous graphene structure on a non-conductive flexible substrate. These synthesized nanomaterials have extensively contributed to the development of EC sensing technology by detecting numerous environmental pollutants (Pb2+, Cd2+, Hg2+, As3+ ions) and biomolecules (dopamine, uric acid) in parts per billion (ppb)