Epitaxial Pt(111) thin film electrodes on YSZ(111) and YSZ(100) — Preparation and characterisation

Abstract

Platinum films with thicknesses up to 1 μm have been deposited on YSZ(111) and on YSZ(100) by pulsed laser deposition (YSZ: yttria-stabilized zirconia). The as-deposited platinum films are nanocrystalline with a grain size in the order of 30 nm. During thermal treatment at 1023 K the microstructure of the films changes due to grain growth, leading to well adhering and well orientated films. Closed cavities are created within the film during the growth. The microstructure and morphology of the films are documented by HRSEM, XRD and XRD pole figures. The high quality of the Pt/YSZ interfaces is documented by high-resolution transmission electron microscopy (HRTEM). The platinum films on (100)-orientated YSZ are polycrystalline with large grains whereas the platinum films on (111)-orientated YSZ are single crystalline with a negligible concentration of grain boundaries. Since these platinum films on YSZ(111) are virtually impermeable for oxygen, microstructures on the basis of these epitaxial films may be used as geometrically and microstructurally well defined model-type electrodes for the study of electrochemical processes at the triple phase boundary Pt(O 2)/YSZ and on the surface of platinum.