Dynamic Structural Evolution Of Mn-Au Alloy And Mnox Nanostructures On Au(111) Under Different Atmospheres

Construction of inverse oxide/metal model catalyst with specific chemical composition and interfacial structure is essential for clarifying their structure-performance relationship. This work describes the structural evolution of Mn-Au surface alloy and two-dimensional manganese oxide (MnOx) islands on Au(111) surface under different treatment conditions. By employing near-ambient pressure scanning tunneling microscopy and X-ray photoelectron spectroscopy, we can obtain four different MnOx structures. Among them, double-layer square lattice Mn3O4(001) and monolayer parallelogram-shaped Mn3O4 are prepared by postannealing Mn-Au surface alloy in "oxygen-poor" and "oxygen-rich" regimes, respectively. Annealing the monolayer parallelogram-shaped Mn3O4 in vacuum to 700 K produces a double-layer structure consisting of Mn3O4 top layer and MnO(111) bottom layer, while double-layer MnO(111) is formed after annealing in vacuum to 800 K. Our study lays the foundation for exploring the catalytic properties of inverse manganese oxide/metal model catalysts.