Dependence of alloying and island composition on terrace width: Growth of Cu on Ag(100)

Beichert, Agnes; Zaum, Christopher; Morgenstern, Karina

doi:10.1103/physrevb.92.045422

Cited by 5 publications

(1 citation statement)

References 23 publications

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“…We speculate that the formation of a Cu Zn site generates a Cu vacancy (Cu v ) which annihilates with a Zn atom within the Zn island or diffusing Zn adatom. The mechanism is clearly different from exchange diffusion processes, e.g., observed for alloying of Cu adatoms on Ag(100) and Pb on Cu(111) . The observed mobility of the Zn island edge or the possibility of diffusing Cu v , sites then explains the spatial correlation of the two sites.…”

Section: Resultscontrasting

confidence: 59%

Atomic-Scale Site Characterization of Cu–Zn Exchange on Cu(111)

et al. 2023

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An accurate understanding of the physicochemical properties of bimetallic heterogeneous catalysts relies on atomicscale knowledge of the surface morphology and the atomic distribution. Alloys of Cu and Zn created during catalyst operation are frequently studied and debated in relation to a description of the active phase of Cu/ZnO/Al 2 O 3 methanol synthesis catalysts. This makes it relevant to build a better understanding of Zn dissolution pathways in Cu surfaces and the resulting surface morphology. Herein, we use scanning tunneling microscopy to investigate surface morphology and the distinct atom site configurations of Zn and Cu on Cu(111) resulting from room-temperature Zn exchange from a Zn monolayer into the topmost layer of Cu(111). A gradual dissolution of Zn islands induces an extensive element intermixing at room temperature, resulting in Zn alloying at Cu terrace lattice sites. In addition, we observe and address an interlayer element exchange between the Zn submonolayers in direct contact with Cu. The exchange process is driven by lattice strain and is strongly facilitated at the perimeter of Zn edges. The STM contrast associated with the resulting intermixed sites is reported together with the simulation of these sites based on density functional theory, showing that imaging of isolated Zn sites in Cu( 111) is sensitive to the STM tip state. The findings provide new insight into the atomic-scale exchange for Zn/Cu bimetallic surfaces, which may be used onward for understanding the debated surface morphology that develops during reductive activation and alloy formation in the Cu/ ZnO/Al 2 O 3 methanol synthesis catalyst.

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Section: Resultscontrasting

confidence: 59%