Titania-coated platinum thin films by MOCVD: electrochemical and photoelectrochemical properties.

Pt films are deposited on glass rods from Pt(acac)2 and H2O in the thickness range 10–200 nm. Voltammetric measurements show that a 100 nm Pt film behaves like a bulk Pt electrode. A series of 100 nm Pt films are then coated with anatase TiO2 films 15–100 nm thick using Ti(OiPr)4 as the precursor. The electrochemical properties of the Pt–TiO2 electrodes, investigated by cyclic voltammetry in aqueous solutions, indicate that the passivating TiO2 layer induces some kinetic inhibitions into the heterogeneous electron transfer process of Ru(NH3)6 3+, which is utilized as a probe molecule. The photoelectrochemical performance of the Pt–TiO2 films demonstrates an optimum behavior for 100 nm TiO2 coatings. The photocatalytic properties of the Pt–TiO2 films can be exploited for electrocatalytic applications in sensor technology.