Water dissociation on mixed Co-Fe oxide bilayer nanoislands on Au(111)

TY - JOUR

T1 - Water dissociation on mixed Co-Fe oxide bilayer nanoislands on Au(111)

AU - Sun, Zhaozong

AU - Rodríguez-Fernández, Jonathan

AU - Lauritsen, Jeppe V.

N1 - Publisher Copyright: © 2022 IOP Publishing Ltd.

PY - 2022/4

Y1 - 2022/4

N2 - We investigate the hydroxylation behaviour of mixed Co-Fe oxide nanoislands synthesized on a Au(111) surface under exposure to water vapour at vacuum conditions. The pure Co and Fe bilayer oxides both become hydroxylated by water exposure in vacuum conditions, albeit to a very different extent. It is however an open question how mixed oxides, exposing sites with a mixed coordination to Fe and Co, behave. By forming surface O species with a mixed Fe/Co coordination, we can investigate the nature of such sites. By means of scanning tunnelling microscopy and x-ray photoelectron spectroscopy, we characterize a series of Co-Fe oxides samples with different Fe contents at the atomic scale and observe a scaling of the hydroxylation degree with the amount of Fe inside the Co-Fe oxides. Our results indicate that the Fe dopants within the Co-Fe oxides have opposing effects on edge and basal plane sites modifying the maximum hydroxylation degree of pure cobalt oxide, perturbing the original binding sites of H, releasing the absorbed H or blocking the diffusion pathway of H.

AB - We investigate the hydroxylation behaviour of mixed Co-Fe oxide nanoislands synthesized on a Au(111) surface under exposure to water vapour at vacuum conditions. The pure Co and Fe bilayer oxides both become hydroxylated by water exposure in vacuum conditions, albeit to a very different extent. It is however an open question how mixed oxides, exposing sites with a mixed coordination to Fe and Co, behave. By forming surface O species with a mixed Fe/Co coordination, we can investigate the nature of such sites. By means of scanning tunnelling microscopy and x-ray photoelectron spectroscopy, we characterize a series of Co-Fe oxides samples with different Fe contents at the atomic scale and observe a scaling of the hydroxylation degree with the amount of Fe inside the Co-Fe oxides. Our results indicate that the Fe dopants within the Co-Fe oxides have opposing effects on edge and basal plane sites modifying the maximum hydroxylation degree of pure cobalt oxide, perturbing the original binding sites of H, releasing the absorbed H or blocking the diffusion pathway of H.

KW - Co oxide

KW - Fe oxide

KW - hydroxylation

KW - mixed oxides

KW - scanning tunnelling microscopy (STM)

KW - water exposure

KW - x-ray photoelectron spectroscopy (XPS)

U2 - 10.1088/1361-648X/ac513a

DO - 10.1088/1361-648X/ac513a

M3 - Journal article

C2 - 35108698

AN - SCOPUS:85125020574

SN - 0953-8984

VL - 34

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

IS - 16

M1 - 164004

ER -