Structural, electronic and chemical properties of low-index high-entropy alloy surfaces

点击翻译按钮获取中文摘要

High-entropy alloys (HEAs) are discussed for applications in the fields of corrosion and wear protection as well as electrocatalysts. Although the surface properties of HEAs play a central role in these applications, they are still largely unexplored. In this project, the properties of low-index (100), (110) and (111) surfaces of the high entropy alloy CoCrFeNi are investigated in detail. Optimized epitaxial layers are used, which are produced by magnetron sputtering on single-crystalline substrates. The surface structures are characterized by low energy electron diffraction, low energy electron microscopy and scanning probe microscopy. The chemical composition of the surfaces is determined by X-ray photoelectron spectroscopy. The dispersion of electronic surfaces states that may occur is elucidated using angle-resolved photo-electron spectroscopy. In addition to the physical properties of the various low-index surfaces, their adsorption behavior with respect to oxygen and water will also be determined. Furthermore, the surfaces will be used in electrochemical studies. In particular, the different orientations will be compared with respect to their catalytic properties in the hydrogen evolution reaction.