Highly Interconnected Macroporous and Transparent Indium Tin Oxide Electrode

A macroporous indium tin oxide (ITO) electrode has been obtained by electrospinning nanofibers from polyvinylpyrrolidone and ITO precursors on a fused silica substrate covered by polystyrene, followed by a heat treatment that induced a drastic modification in the material texture. The resulting electrode structure is consisting of highly interconnected nanofilaments of sizes between 70 and 170nm. The electrode is robust, fixed to the substrate, transparent in the visible light region, and possesses excellent electrochemical properties in comparison to a planar ITO electrode, that is, improved reversibility with ferrocenedimethanol and greatly enhanced oxidation for ascorbic acid. SEM and XRD measurements confirm ITO formation. This porous ITO electrode can be modified electrochemically with mesostructured methylated silica and applied to a combined electrochemical and spectral detection of industrial dyes (methylene blue, Meldola's blue, and methylene green) from water. For methylene blue analysis, a linear range of detection between 20nM and 2 mu M and a limit of detection of 17nM are observed. Finally, the spectroelectrochemical analysis of a solution with mixed dyes has been performed.