화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.149, No.9, B450-B455, 2002
A study of anodic films and processes on titanium-copper metallic glasses
The objective of our research was to study the electrochemical behavior of glassy alloys containing an early and a late transition metal, as dependent on their composition and the properties of anodic surface layers. The Ti100-xCux glassy alloy with x = 34, 50, and 66 wt % was investigated using cyclic voltammetry, impedance spectroscopy, and photoelectrochemistry in a borate buffer, pH 9.2, and compared to its polycrystalline components (Ti and Cu). The surface films on Ti-Cu alloys, as well as the film on titanium, exhibit specific features characteristic for n-type semiconductor electrodes. Anodic kinetics suggest that the oxygen evolution reaction (OER) is greatly facilitated at the oxidized alloys as compared to the pure components. Increasing the Cu content in the alloy causes increasing catalytic activity for oxygen evolution as well as increasing corrosion protection due to the TiO2 content of the anodic oxide. The mechanism of the OER was interpreted in terms of electron tunneling from the oxide ions in the active centers in the electrode (into the empty conduction band) as the rate-determining step followed by a faster electrochemical process.