TY - JOUR
T1 - Hydroxylation of an ultrathin Co3O4(111) film on Ir(100) studied by in situ ambient pressure XPS and DFT
AU - Haunold, Thomas
AU - Anic, Kresimir
AU - Genest, Alexander
AU - Rameshan, Christoph
AU - Roiaz, Matteo
AU - Li, Hao
AU - Wicht, Thomas
AU - Knudsen, Jan
AU - Rupprechter, Günther
N1 - Publisher Copyright: © 2024 The Author(s)
PY - 2024/9/26
Y1 - 2024/9/26
N2 - In the present work, we have studied the interaction of water with spinel cobalt oxide (Co3O4), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co3O4(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H2O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co3O4(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co3O4(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H2O dissociation and OH formation, blocking exposed Co2+ ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H2O traces in reactive feeds.
AB - In the present work, we have studied the interaction of water with spinel cobalt oxide (Co3O4), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co3O4(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H2O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co3O4(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co3O4(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H2O dissociation and OH formation, blocking exposed Co2+ ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H2O traces in reactive feeds.
KW - Cobalt oxide
KW - Density functional theory
KW - In situ studies
KW - Model catalysis
KW - Photoelectron spectroscopy
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=85205564178&partnerID=8YFLogxK
U2 - 10.1016/j.susc.2024.122618
DO - 10.1016/j.susc.2024.122618
M3 - Article
AN - SCOPUS:85205564178
SN - 0039-6028
VL - 751.2025
JO - Surface Science
JF - Surface Science
IS - January
M1 - 122618
ER -