Structural effects on the dynamics of an electrocatalytic oscillator

The electrocatalytic oxidation of hydrogen in the presence of Cu²⁺ and Cl^- ions under galvanostatic conditions has been studied on the three low-index plane surfaces of platinum. Over the parameter ranges investigated and with the electrode pretreatment used, no oscillations were observed on Pt(110), whereas only simple periodic oscillations were seen with Pt(111). The Pt(100) surface, on the other hand, exhibited a variety of oscillation types, including simple periodic oscillations, period-doubling, chaos and mixed-mode behavior as two parameters, copper ion concentration and current density, were varied. The dynamics on Pt(100) turned out qualitatively very similar to that observed previously on polycrystalline platinum electrodes.