Influence of platinum content on semiconductor and electrochemical properties of materials based on titanium suboxides

Abstract

The effect of platinum content on the surface morphology, phase composition and electrochemical properties of materials based on titanium suboxides was investigated. Titanium suboxides are formed at the stage of coating reduction under cathodic polarization, which allows the formation of a porous developed surface for electrodeposition of catalytic platinum layers. The main allotropic modification of TiOx in the studied composite materials is anatase, which contains particles of elemental titanium and platinum. The investigated materials are highly doped semiconductors with a high concentration of charge carriers. With an increase in the platinum content, an extreme dependence of the potential of flat zones is observed, which is associated with the formation of a composite material. The electrocatalytic activity was studied in the reactions of oxygen and hydrogen evolution. The overvoltage of oxygen production on platinum-containing materials is much lower than on the TiOx electrode. The slope of the linear dependence of the potential on the current density decreases with an increase in platinum content. The Tafel slope for the studied materials in the hydrogen evolution reaction was 160 mVdec–1 for coatings containing 0.25 mgcm–2 Pt; whereas it was equal to 42 and 43 mVdec–1 for electrodes with 0.5 and 2 mgcm–2 Pt, respectively.