TY - JOUR

T1 - CO Adsorption on Reconstructed Ir(100) Surfaces from UHV to mbar Pressure

T2 - A LEED, TPD, and PM-IRAS Study

AU - Anic, Kresimir

AU - Bukhtiyarov, Andrey V.

AU - Li, Hao

AU - Rameshan, Christoph

AU - Rupprechter, Günther

N1 - Publisher Copyright: © 2016 American Chemical Society.

PY - 2016/4/21

Y1 - 2016/4/21

N2 - Clean and stable surface modifications of an iridium (100) single crystal, i.e.; the (1 × 1) phase, the (5 × 1) reconstruction, and the oxygen-terminated (2 × 1)-O surface, were prepared and characterized by low energy electron diffraction (LEED), temperature-programmed desorption (TPD), infrared reflection absorption spectroscopy (IRAS) and polarization modulation IRAS (PM-IRAS). The adsorption of CO in UHV and at elevated (mbar) pressure/temperature was followed both ex situ and in situ on all three surface modifications, with a focus on mbar pressures of CO. The Ir(1 × 1) surface exhibited c(4 × 2)/c(2 × 2) and c(6 × 2) CO structures under low pressure conditions, and remained stable up to 100 mbar and 700 K. For the (2 × 1)-O reconstruction CO adsorption induced a structural change from (2 × 1)-O to (1 × 1), as confirmed by LEED, TPD, and IR. For Ir (2 × 1)-O TPD indicated that CO reacted with surface oxygen forming CO2. The (5 × 1) reconstruction featured a reversible and dynamic behavior upon CO adsorption, with a local lifting of the reconstruction to (1 × 1). After CO desorption, the (5 × 1) structure was restored. All three reconstructions exhibited CO adsorption with on-top geometry, as evidenced by IR. With increasing CO exposure the resonances shifted to higher wavenumber, due to adsorbate-adsorbate and adsorbate-substrate interactions. The largest wavenumber shift (from 2057 to 2100 cm-1) was observed for Ir(5 × 1) upon CO dosing from 1 L to 100 mbar.

AB - Clean and stable surface modifications of an iridium (100) single crystal, i.e.; the (1 × 1) phase, the (5 × 1) reconstruction, and the oxygen-terminated (2 × 1)-O surface, were prepared and characterized by low energy electron diffraction (LEED), temperature-programmed desorption (TPD), infrared reflection absorption spectroscopy (IRAS) and polarization modulation IRAS (PM-IRAS). The adsorption of CO in UHV and at elevated (mbar) pressure/temperature was followed both ex situ and in situ on all three surface modifications, with a focus on mbar pressures of CO. The Ir(1 × 1) surface exhibited c(4 × 2)/c(2 × 2) and c(6 × 2) CO structures under low pressure conditions, and remained stable up to 100 mbar and 700 K. For the (2 × 1)-O reconstruction CO adsorption induced a structural change from (2 × 1)-O to (1 × 1), as confirmed by LEED, TPD, and IR. For Ir (2 × 1)-O TPD indicated that CO reacted with surface oxygen forming CO2. The (5 × 1) reconstruction featured a reversible and dynamic behavior upon CO adsorption, with a local lifting of the reconstruction to (1 × 1). After CO desorption, the (5 × 1) structure was restored. All three reconstructions exhibited CO adsorption with on-top geometry, as evidenced by IR. With increasing CO exposure the resonances shifted to higher wavenumber, due to adsorbate-adsorbate and adsorbate-substrate interactions. The largest wavenumber shift (from 2057 to 2100 cm-1) was observed for Ir(5 × 1) upon CO dosing from 1 L to 100 mbar.

UR - http://www.scopus.com/inward/record.url?scp=84971383923&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.5b12494

DO - 10.1021/acs.jpcc.5b12494

M3 - Article

AN - SCOPUS:84971383923

VL - 120.2016

SP - 10838

EP - 10848

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 20

ER -