Details
| Original language | English |
|---|---|
| Article number | 154705 |
| Journal | Journal of Chemical Physics |
| Volume | 148 |
| Issue number | 15 |
| Early online date | 19 Apr 2018 |
| Publication status | Published - 21 Apr 2018 |
Abstract
Chemical waves in the H2 + O2 reaction on a Rh(111) surface alloyed with Ni [ΘNi < 1.5 monolayers (ML)] have been investigated in the 10-7 and 10-6 mbar range at T = 773 K using scanning photoelectron microscopy and x-ray photoelectron spectroscopy as in situ methods. The local intensity variations of the O 1s and the Ni 2p signal display an anticorrelated behavior. The coincidence of a high oxygen signal with a low Ni 2p intensity, which seemingly contradicts the chemical attraction between O and Ni, has been explained with a phase separation of the oxygen covered Rh(111)/Ni surface into a 3D-Ni oxide and into a Ni poor metallic phase. Macroscopic NiO islands (≈1 μm size) formed under reaction conditions have been identified as 2D-Ni oxide. Titration experiments of the oxygen covered Rh(111)/Ni surface with H2 demonstrated that the reactivity of oxygen is decreased by an order of magnitude through the addition of 0.6 ML Ni. An excitation mechanism is proposed in which the periodic formation and reduction of NiO modulate the catalytic activity.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Journal of Chemical Physics, Vol. 148, No. 15, 154705, 21.04.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Chemical waves in the O2 + H2 reaction on a Rh(111) surface alloyed with nickel. II. Photoelectron spectroscopy and microscopy
AU - Smolinsky, Tim
AU - Homann, Mathias
AU - Von Boehn, Bernhard
AU - Gregoratti, Luca
AU - Amati, Matteo
AU - Al-Hada, Mohamed
AU - Sezen, Hikmet
AU - Imbihl, Ronald
N1 - © 2018 Author(s).
PY - 2018/4/21
Y1 - 2018/4/21
N2 - Chemical waves in the H2 + O2 reaction on a Rh(111) surface alloyed with Ni [ΘNi < 1.5 monolayers (ML)] have been investigated in the 10-7 and 10-6 mbar range at T = 773 K using scanning photoelectron microscopy and x-ray photoelectron spectroscopy as in situ methods. The local intensity variations of the O 1s and the Ni 2p signal display an anticorrelated behavior. The coincidence of a high oxygen signal with a low Ni 2p intensity, which seemingly contradicts the chemical attraction between O and Ni, has been explained with a phase separation of the oxygen covered Rh(111)/Ni surface into a 3D-Ni oxide and into a Ni poor metallic phase. Macroscopic NiO islands (≈1 μm size) formed under reaction conditions have been identified as 2D-Ni oxide. Titration experiments of the oxygen covered Rh(111)/Ni surface with H2 demonstrated that the reactivity of oxygen is decreased by an order of magnitude through the addition of 0.6 ML Ni. An excitation mechanism is proposed in which the periodic formation and reduction of NiO modulate the catalytic activity.
AB - Chemical waves in the H2 + O2 reaction on a Rh(111) surface alloyed with Ni [ΘNi < 1.5 monolayers (ML)] have been investigated in the 10-7 and 10-6 mbar range at T = 773 K using scanning photoelectron microscopy and x-ray photoelectron spectroscopy as in situ methods. The local intensity variations of the O 1s and the Ni 2p signal display an anticorrelated behavior. The coincidence of a high oxygen signal with a low Ni 2p intensity, which seemingly contradicts the chemical attraction between O and Ni, has been explained with a phase separation of the oxygen covered Rh(111)/Ni surface into a 3D-Ni oxide and into a Ni poor metallic phase. Macroscopic NiO islands (≈1 μm size) formed under reaction conditions have been identified as 2D-Ni oxide. Titration experiments of the oxygen covered Rh(111)/Ni surface with H2 demonstrated that the reactivity of oxygen is decreased by an order of magnitude through the addition of 0.6 ML Ni. An excitation mechanism is proposed in which the periodic formation and reduction of NiO modulate the catalytic activity.
UR - http://www.scopus.com/inward/record.url?scp=85045854372&partnerID=8YFLogxK
U2 - 10.1063/1.5020381
DO - 10.1063/1.5020381
M3 - Article
C2 - 29679964
AN - SCOPUS:85045854372
VL - 148
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 15
M1 - 154705
ER -