Prussian Blue Films Produced by Pentacyanidoferrate(II) and Their Application as Active Electrochemical Layers

摘要

Iron complexes such as ferri/ferrocyanides are usually employed as electrochemical mediators in portable devices for the quick diagnosis of diseases. Stable complexes designed for the electrochemical active layer may render devices with better performance and lifetimes than conventional devices. In this work we have synthesized and characterized spectroscopically, electrochemically, and by DFT the complex Na_4[Fe(CN)_5(isn)] (isn = isonicotinate). This complex was used as a single-source precursor of Prussian Blue (PB) in solution at pH 2.0 and 3.0, as confirmed by UV/Vis spectroscopy. Potentiostatic deposition of PB onto glassy carbon electrodes provided stable films at pH 3.0 and 5.0, with electrocatalytic activity for ascorbic acid oxidation with a linear response in the range 20-200 μM and an limit of detection of 12 μM. The anodic peak potential of the modified electrodes varied with solution pH with a minimum value of 0.350 V versus NHE at pH 5.0.