上海科技大学知识管理系统

The restructuring of dilute alloys under gas environments has shown a great impact on their catalytic performance due to intriguing structural sensitivity, but the structural dynamics and underlying mechanism remains elusive. Herein, we directly resolved the distinct dynamic behaviors of PdFe0.08 dilute alloys under CO or O2 environment by multidimensional imaging. The stronger binding of gaseous CO with Fe atoms stimulates Fe segregation out of the PdFe0.08, resulting in 3D growth of Fe islands, whereas the dissociative adsorption of O2 results in 2D layer-by-layer growth of segregated FeO as encapsulation overlayers that bind strongly with the Pd surface underneath. Such varied structures remarkably tune the catalytic activity for CO oxidation, showing a considerably high activity for a CO-treated sample. Our results reveal the competitive mechanism between adsorbate-metal and metal-metal interaction for gas-induced surface segregation, which should be highly considered for the rational design of dilute alloys with dynamically tuned structure and reactivity. © 2024 American Chemical Society.