Electrochemistry in the Presence of Mesoporous TiO₂ Phytate Nanofilms

Thin composite organic - inorganic membranes are formed at electrode surfaces via a layer-by-layer deposition process employing TiO₂ nanoparticles and phytic acid as molecular binder. The mesoporous membranes form uniformly across platinum and glass surfaces and are shown via conducting atomic force microscopy (C-AFM) to behave in dry state as electrically insulating films. Voltammetry at platinum electrodes of 1.5 mm, 100 μm, and 10 μm diameter is used to survey the effect of the composite membrane on electrochemical processes. The electrode diameter as well as concentration and nature of electrolyte have a considerable effect on the electrode process. For the one electron reduction of Ru(NH₃)₆³⁺ in aqueous media adsorption effects, mobility effects, and accumulation or 'memory' effects are observed. Similarly, protons or cationic molecules such as dopamine can be accumulated and 'stored' in the membrane and then transferred to a clean electrolyte for analysis.