Structural and electronic properties of Fe dopants in cobalt oxide nanoislands on Au(111)

TY - JOUR

T1 - Structural and electronic properties of Fe dopants in cobalt oxide nanoislands on Au(111)

AU - Rodríguez-Fernández, Jonathan

AU - Sun, Zhaozong

AU - Zhang, Liang

AU - Tan, Ting

AU - Curto, Anthony

AU - Fester, Jakob

AU - Vojvodic, Aleksandra

AU - Lauritsen, Jeppe V.

PY - 2019/1/28

Y1 - 2019/1/28

N2 - Mixed metal oxides of earth-abundant 3d transition metals are an interesting class of materials that show interesting magnetic properties and a significant synergistic effect as catalysts for electrochemical oxygen evolution compared to simple unary oxides. However, the exact atomic-scale nature of such mixed oxide phases and the link to their interesting physico-chemical properties are poorly understood. Here, a combination of scanning tunneling microscopy and x-ray photoemission spectroscopy reveals that Fe species embed in a facile way into CoO bilayers on Au(111) resulting in an Fe doped oxide. Density functional theory and the spectroscopic fingerprint from x-ray photoemission spectroscopy reveal that the Fe dopants in the cobalt oxide matrix assume a higher oxidation state than in the structurally corresponding unary bilayer oxide. Furthermore, the substituted Fe is structurally displaced further away from the Au than the metal in either of the corresponding pure unary oxides. Both O and to a smaller extent Co in the nearest coordination shell are also structurally and electronically perturbed. The interesting effects observed in the bilayer binary oxides may enable a better fundamental understanding of the nature of doping of metal oxides, in general, and promotion effects in catalytic applications.

AB - Mixed metal oxides of earth-abundant 3d transition metals are an interesting class of materials that show interesting magnetic properties and a significant synergistic effect as catalysts for electrochemical oxygen evolution compared to simple unary oxides. However, the exact atomic-scale nature of such mixed oxide phases and the link to their interesting physico-chemical properties are poorly understood. Here, a combination of scanning tunneling microscopy and x-ray photoemission spectroscopy reveals that Fe species embed in a facile way into CoO bilayers on Au(111) resulting in an Fe doped oxide. Density functional theory and the spectroscopic fingerprint from x-ray photoemission spectroscopy reveal that the Fe dopants in the cobalt oxide matrix assume a higher oxidation state than in the structurally corresponding unary bilayer oxide. Furthermore, the substituted Fe is structurally displaced further away from the Au than the metal in either of the corresponding pure unary oxides. Both O and to a smaller extent Co in the nearest coordination shell are also structurally and electronically perturbed. The interesting effects observed in the bilayer binary oxides may enable a better fundamental understanding of the nature of doping of metal oxides, in general, and promotion effects in catalytic applications.

KW - CATALYSTS

KW - CO

KW - FILMS

KW - GOLD

KW - MANGANESE

KW - NANOPARTICLES

KW - OXYGEN-EVOLUTION ELECTROCATALYSTS

KW - SITES

KW - SPINEL COFE2O4

KW - STABILITY

UR - http://www.scopus.com/inward/record.url?scp=85060618797&partnerID=8YFLogxK

U2 - 10.1063/1.5052336

DO - 10.1063/1.5052336

M3 - Journal article

C2 - 30709272

AN - SCOPUS:85060618797

SN - 0021-9606

VL - 150

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

IS - 4

M1 - 041731

ER -