Superstable Advanced Hydrogen Peroxide Transducer Based on Transition Metal Hexacyanoferrates

We report on a superstable hydrogen peroxide (H2O2) transducer made by sequential deposition of the iron- and nickel-hexacyanoferrate (NiHCF) layers. Both chemical and mechanical stability of the latter, as well as similarity of its structure to Prussian Blue (PB) provide a substantial stabilization of the most advantageous H2O2 transducer. The electrochemically deposited five bilayers of PB-NiHCF exhibit a complete stability under the continuous wall-jet flow of 1 mM of H2O2 during more than 2 h, maintaining current at a level of 0.2 mA cm(-2), whereas common Prussian Blue loses half of its response within the first 20-25 min. Even being deposited in the open circuit regime on screen-printed electrodes, PB-NiHCF bilayers dramatically improve tolerance of the resulting transducer to alkaline solutions and iron ligands. Despite their 2-2.5 times decreased sensitivity (compared to common Prussian Blue), the sequentially deposited bilayers of PB-NiHCF provide a similar dynamic range of the transducer due to the decreased noise level.