Mesoporous platinum hosts for electrode∣liquid∣liquid - Triple phase boundary redox systems

Mesoporous metal hosts are attractive electrode materials for complex electrode reactions, for example those involving a system of two immiscible liquids. Here we show that a solution of tetraphenylporphyrianto manganese (MnTPP) in 4-(3-phenylpropyl)-pyridine (PPP) organic liquid can be immobilized into mesoporous platinum thin films electrodeposited from a liquid crystalline template. When immersed in an aqueous solution, the organic liquid remains immobilized inside the mesoporous platinum framework. Well-defined, stable, and reproducible ion transfer voltammograms are recorded. The effects of mesoporous platinum membrane thickness (volume), scan rate, and the type of aqueous electrolyte anion (for Cl−, PF6-, ClO4-, CN−, SCN− and NO3-) are investigated. Mesoporous platinum is proposed as a very effective electrode material for liquid∣liquid anion sensing and for other applications of electrochemically driven liquid∣liquid redox systems.