TY - JOUR
T1 - Identification of O-rich structures on platinum(111)-supported ultrathin iron oxide films
AU - Merte, Lindsay R.
AU - Bai, Yunhai
AU - Zeuthen, Helene
AU - Peng, Guowen
AU - Lammich, Lutz
AU - Besenbacher, Flemming
AU - Mavrikakis, Manos
AU - Wendt, Stefan
PY - 2016/10
Y1 - 2016/10
N2 - Using high-resolution scanning tunneling microscopy (STM) we have studied the oxidation of ultrathin FeO films grown on Pt(111). At the initial stage of the FeO film oxidation by atomic oxygen exposure, we identified three distinct types of line defects, all of which form boundaries between FeO domains of opposite orientation. Two types of line defects appearing bright (type-i) and dark (type-ii) in the STM images at typical scanning parameters are “metallic”, whereas the third line defect exhibits nonmetallic behavior (type-iii). Atomic-scale structure models of these line defects are proposed, with type-i defects exhibiting 4-fold coordinated Fe atoms, type-ii exhibiting 2-fold coordinated O atoms, and type-iii exhibiting tetrahedrally-coordinated Fe atoms. In addition, FeO
2 trilayer islands are formed upon oxidation, which appear at FCC-type domains of the moiré structure. At high scanning bias, distinct protrusions on the trilayer islands are observed over surface O ions, which are assigned to H adatoms. The experimental data are supported by density functional theory (DFT) calculations, in which bare and hydroxylated FeO
2 trilayer islands are compared. Finally, we compare the formation of O-rich features on continuous FeO films using atomic oxygen with the oxidation of Pt(111)-supported FeO islands accomplished by O
2 exposure.
AB - Using high-resolution scanning tunneling microscopy (STM) we have studied the oxidation of ultrathin FeO films grown on Pt(111). At the initial stage of the FeO film oxidation by atomic oxygen exposure, we identified three distinct types of line defects, all of which form boundaries between FeO domains of opposite orientation. Two types of line defects appearing bright (type-i) and dark (type-ii) in the STM images at typical scanning parameters are “metallic”, whereas the third line defect exhibits nonmetallic behavior (type-iii). Atomic-scale structure models of these line defects are proposed, with type-i defects exhibiting 4-fold coordinated Fe atoms, type-ii exhibiting 2-fold coordinated O atoms, and type-iii exhibiting tetrahedrally-coordinated Fe atoms. In addition, FeO
2 trilayer islands are formed upon oxidation, which appear at FCC-type domains of the moiré structure. At high scanning bias, distinct protrusions on the trilayer islands are observed over surface O ions, which are assigned to H adatoms. The experimental data are supported by density functional theory (DFT) calculations, in which bare and hydroxylated FeO
2 trilayer islands are compared. Finally, we compare the formation of O-rich features on continuous FeO films using atomic oxygen with the oxidation of Pt(111)-supported FeO islands accomplished by O
2 exposure.
KW - ACTIVE-SITES
KW - AUGMENTED-WAVE METHOD
KW - BASIS-SET
KW - CATALYTIC-OXIDATION
KW - Catalysis
KW - Density functional theory (DFT)
KW - FeO2 (-) (x) islands
KW - Iron oxide
KW - METAL-SUPPORT INTERACTIONS
KW - O adatom dislocations
KW - OXYGEN
KW - PT(111)
KW - STM
KW - Scanning tunneling microscopy (STM)
KW - TEMPERATURE CO OXIDATION
KW - TOTAL-ENERGY CALCULATIONS
UR - http://www.scopus.com/inward/record.url?scp=84955578607&partnerID=8YFLogxK
U2 - 10.1016/j.susc.2015.12.031
DO - 10.1016/j.susc.2015.12.031
M3 - Journal article
SN - 0039-6028
VL - 652
SP - 261
EP - 268
JO - Surface Science
JF - Surface Science
ER -