biostudies-literatureMissaoui GDeutsche ForschungsgemeinschaftMinistry of Lower Saxony45026-45032https://www.ebi.ac.uk/biostudies/studies/S-EPMC12367229biostudies-literatureUnknown17(31)The mixing characteristics of oxide materials largely depend on the dimensionality of the system, and many oxide-alloy structures in three dimensions (3D) do not have a 2D analog. To unravel fundamental alloying mechanisms in 2D, V/Cr mixing into oxide thin films is investigated on Pt(111) by scanning tunneling microscopy and density functional theory. The experiments reveal flat, double-stack islands made of a compact bottom and a honeycomb top layer with a 4.5 Å total height. The energetically most favorable structure-match comprises an O-Cr-O trilayer at the interface to the Pt(111) capped by a mixed V/Cr honeycomb top layer. The structure is stabilized by strong interlayer adhesion, reinforced by a charge transfer toward the central trilayer from the metal support and the honeycomb plane. A negative V/Cr mixing enthalpy arises from the presence of two distinct surface sites that enable formation of tetrahedrally coordinated V⁵⁺ and octahedrally coordinated Cr³⁺ cations. The identified thin-film structure bears resemblance to a (111) cut of a hypothetical V/Cr spinel, a unique 2D configuration without bulk equivalent that is stabilized solely by its nanoscale thickness and a strong coupling to the Pt support.ACS applied materials & interfacesChromium/Vanadium Mixed Oxide Films on Pt(111): Revealing Oxide Alloying Mechanisms in Two Dimensions.PMC12367229Ni 650/5_2Missaoui GWemhoff PINoguera CNilius NGoniakowski JfalseChromium/Vanadium Mixed Oxide Films on Pt(111): Revealing Oxide Alloying Mechanisms in Two Dimensions.The mixing characteristics of oxide materials largely depend on the dimensionality of the system, and many oxide-alloy structures in three dimensions (3D) do not have a 2D analog. To unravel fundamental alloying mechanisms in 2D, V/Cr mixing into oxide thin films is investigated on Pt(111) by scanning tunneling microscopy and density functional theory. The experiments reveal flat, double-stack islands made of a compact bottom and a honeycomb top layer with a 4.5 Å total height. The energetically most favorable structure-match comprises an O-Cr-O trilayer at the interface to the Pt(111) capped by a mixed V/Cr honeycomb top layer. The structure is stabilized by strong interlayer adhesion, reinforced by a charge transfer toward the central trilayer from the metal support and the honeycomb plane. A negative V/Cr mixing enthalpy arises from the presence of two distinct surface sites that enable formation of tetrahedrally coordinated V⁵⁺ and octahedrally coordinated Cr³⁺ cations. The identified thin-film structure bears resemblance to a (111) cut of a hypothetical V/Cr spinel, a unique 2D configuration without bulk equivalent that is stabilized solely by its nanoscale thickness and a strong coupling to the Pt support.2025-01-01T00:00:00Z2025 Aug2026-05-05T12:35:32.074Z2026-04-07T21:42:15.356ZS-EPMC123672294071198010.1021/acsami.5c05932