Electrochemical synthesis and properties of titanium dioxide–titanium suboxides composite for cathodic protection

Abstract

This study reports a combined electrochemical method for preparation of a titanium dioxide–suboxide composite with an electrochemically deposited non-continuous platinum layer on the surface, which can be used for cathodic protection of metal structures. Platinum significantly modifies the properties of TiO2, stabilizes the surface, and prevents the formation of a passive non-conductive layer. The coating has significant advantages compared to Ti/Pt, traditionally used for electrochemical protection, as the platinum content in the composite is significantly reduced. Unlike a continuous precious metal layer, this method of composite formation, particularly thermal treatment in an air atmosphere at 5000C, allows protecting the platinum, which is encapsulated in titanium oxides, and avoiding the creeping passivation typical of traditionally used materials. The surface of the coatings was investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray microanalysis. Studies of the electrocatalytic properties, especially concerning the oxygen evolution reaction, revealed deviations of the Tafel slope from the theoretical value, which is explained by structural heterogeneity and the presence of a semiconductor component. The stability and corrosion resistance of the composites were studied. It was found that the properties remain unchanged even after prolonged exposure to a corrosive environment.