The reduction of oxygen on Pt-TiO2 coated Ti electrodes in alkaline solution

The electrochemical reduction of O-2 was studied on TiO2 and Pt-TiO2 coated Ti electrodes using the rotating disk electrode technique. The Pt-TiO2 coa tings were prepared by the thermal decomposition method in the Pt compositi on range 10-100 wt %. Tafel plots with two distinct slope regions were obse rved for the reduction of O-2 on the Pt-TiO2 electrodes of high Pt content. The electrocatalytic activity toward oxygen reduction decreased remarkably for the electrodes containing less than 35% Pt. The activity decrease was explained by an electrode resistance increase at lower Pt contents. Cyclic voltammetric measurements revealed that the electrode behavior was strongly dependent on the Pt content in the coating. The surface of electrodes was characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. (C) 1999 The Electrochemical Society. S0013-46 51(98)05-029-0. All rights reserved.