Structural, electronic and adsorption properties of V–Rh(111) subsurface alloy

• Published in: Journal of alloys and compounds Vol. 543; pp. 189 - 196
• Main Authors: Píš, I., Skála, T., Cabala, M., Šutara, F., Libra, J., Škoda, M., Matolín, V., Nehasil, V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05.12.2012; Elsevier
• Subjects: Adsorption; Alloy systems; Carbon monoxide; Chemisorption; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic band structure; Electronic structure; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Impurity and defect levels; energy states of adsorbed species; Photoelectron spectroscopies; Physics; Reconstruction; Solid surfaces and solid-solid interfaces; Surface and interface electron states; Surface chemistry; Surface structure and topography; Surfaces and interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Synchrotron radiation; Transition metal alloys and compounds; Vanadium; Vapor deposition; Transition metal alloys and compounds; Vapor deposition; Surfaces and interfaces; Photoelectron spectroscopies; Electronic band structure; Synchrotron radiation; Chemisorption; Annealing; Vanadium; Surface electron state; Rhodium alloys; XRD; Surface structure; Surface reconstruction; Adsorption; Photoelectron diffraction; Chemical composition; LEED; Carbon monoxide; Atomic structure; Subsurface
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.07.122

► V–Rh(111) subsurface alloy with (2×2) surface reconstruction was prepared. ► Substitutional alloy with Rh3V composition and L12 structure was formed. ► Decreased density of states at the Fermi edge was observed upon alloying. ► Electronic changes were correlated with lower reactivity towards CO adsorption. ► Oxygen adsorbed on the surface reacted with the subsurface vanadium. V–Rh(111) bimetallic systems were prepared by deposition of 0.4 and 2.5ML of vanadium on Rh(111) surface at 823K and by annealing up to 1023K. Subsurface alloys of similar composition and electronic structure were formed. On the latter one, (2×2) surface reconstruction was observed. Electronic structure of the V–Rh(111) subsurface alloys was studied by photoelectron spectroscopy utilizing synchrotron radiation. Atomic structure was studied by means of LEED and X-ray photoelectron diffraction. Chemisorption properties were probed by CO and O2 adsorption. The topmost atomic layer with (2×2) reconstruction consisted exclusively of Rh atoms. The obtained results indicate formation of alloy with Rh3V composition and L12-type structure. Changes observed in the electronic structure were correlated with lower reactivity towards CO adsorption. The photoemission data indicate that the CO saturation coverage at 300K is reduced to less than half on the alloy surface as compared to clean Rh(111). Oxygen adsorbed on the alloy surface strongly interacted with the subsurface vanadium and induced formation of a surface vanadium oxide.