Adsorption and Activation of CO on Co<sub>3</sub>O<sub>4</sub>(111) Thin Films

Ferstl, Pascal; Mehl, Sascha; Arman, Mohammad A.; Schuler, Mona; Toghan, Arafat; László, B.; Lykhach, Yaroslava; Brummel, Olaf; Lundgren, Edvin; Knudsen, Jan; Hammer, Lutz; Schneider, M. Alexander; Libuda, Jörg

doi:10.1021/acs.jpcc.5b04145

Cited by 74 publications

(101 citation statements)

References 63 publications

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“…49). In agreement with the STM results discussed in Section 3.1, this observation clearly shows that the deposited Co does not form three-dimensional metallic islands, as is normally observed for metal deposition on oxide surfaces.…”

Section: Co Adsorption At Co Deposits In Co 3 O 4 (111)/ir(100) Probesupporting

confidence: 90%

“…49 We found that at low exposure CO adsorbs at Co 2+ centers, giving rise to a sharp band around 2170 cm À1 . 49 We found that at low exposure CO adsorbs at Co 2+ centers, giving rise to a sharp band around 2170 cm À1 .…”

Section: Co Adsorption At Co Deposits In Co 3 O 4 (111)/ir(100) Probementioning

confidence: 63%

“…29 The present work aims at the development of new cobaltoxide-based model systems which allow us to study their surface chemistry under well-controlled ultrahigh vacuum (UHV) conditions. 49 We investigated the adsorbate phases of CO on Co 3 O 4 (111) and showed that, in addition to the molecularly adsorbed CO, a carbonate species is formed at the side facets of the Co 3 O 4 (111). [38][39][40][41][42][43][44][45][46][47][48] In a unique fashion, these films allow varying the stoichiometry, the surface orientation, the film thickness, and the defect density.…”

Section: Introductionmentioning

confidence: 99%

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Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

Mehl

Ferstl

Schuler

et al. 2015

Phys. Chem. Chem. Phys.

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Cobalt oxide nanomaterials show high activity in several catalytic reactions thereby offering the potential to replace noble metals in some applications. We have developed a well-defined model system for partially reduced cobalt oxide materials aiming at a molecular level understanding of cobalt-oxide-based catalysis. Starting from a well-ordered Co3O4(111) film on Ir(100), we modified the surface by deposition of metallic cobalt. Growth, structure, and adsorption properties of the cobalt-modified surface were investigated by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and infrared reflection absorption spectroscopy (IRAS) using CO as a probe molecule. The deposition of a submonolayer of cobalt at 300 K leads to the formation of atomically dispersed cobalt ions distorting the surface layer of the Co3O4 film. Upon annealing to 500 K the Co ions are incorporated into the surface layer forming ordered two-dimensional CoO islands on the Co3O4 grains. At 700 K, Co ions diffuse from the CoO islands into the bulk and the ordered Co3O4(111) surface is restored. Deposition of larger amounts of Co at 300 K leads to formation of metallic Co aggregates on the dispersed cobalt phase. The metallic particles sinter at 500 K and diffuse into the bulk at 700 K. Depending on the degree of bulk reduction, extended Co3O4 grains switch to the CoO(111) structure. All above structures show characteristic CO adsorption behavior and can therefore be identified by IR spectroscopy of adsorbed CO.

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Section: Co Adsorption At Co Deposits In Co 3 O 4 (111)/ir(100) Probesupporting

confidence: 90%

Section: Co Adsorption At Co Deposits In Co 3 O 4 (111)/ir(100) Probementioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

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Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

Mehl

Ferstl

Schuler

et al. 2015

Phys. Chem. Chem. Phys.

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“…S5 of the supplementary material), which corresponds to saturation of the defect peaks plus 1% of the monolayer coverage, reveal a single peak at 291.3 eV, identical to that of the physisorbed monolayer. Since carbonate species typically appear in the range 287-289 eV, 39,40 we conclude that CO 2 adsorbed at defects is also physisorbed.…”

Section: B Photoelectron Spectroscopymentioning

confidence: 79%

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

Pavelec

Hulva

Halwidl

et al. 2017

The Journal of Chemical Physics

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The adsorption of CO 2 on the Fe 3 O 4 (001)-( √ 2 × √ 2)R45 • surface was studied experimentally using temperature programmed desorption (TPD), photoelectron spectroscopies (UPS and XPS), and scanning tunneling microscopy. CO 2 binds most strongly at defects related to Fe 2+ , including antiphase domain boundaries in the surface reconstruction and above incorporated Fe interstitials. At higher coverages, CO 2 adsorbs at fivefold-coordinated Fe 3+ sites with a binding energy of 0.4 eV. Above a coverage of 4 molecules per (• unit cell, further adsorption results in a compression of the first monolayer up to a density approaching that of a CO 2 ice layer. Surprisingly, desorption of the second monolayer occurs at a lower temperature (≈84 K) than CO 2 multilayers (≈88 K), suggestive of a metastable phase or diffusion-limited island growth. The paper also discusses design considerations for a vacuum system optimized to study the surface chemistry of metal oxide single crystals, including the calibration and characterisation of a molecular beam source for quantitative TPD mea-

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“…8(a)], due to conversion to a spinel Co 3 O 4 (100) film. In the corresponding C 1s spectrum recorded at 300 K we observe two peaks located at 288.7 eV and 291.2 eV assigned to carbonates (Ferstl et al, 2015) and gas-phase CO molecules, respectively. The intensity of the carbonate component first increases upon heating and reaches a maximum at a temperature of 350 K. At higher temperature the intensity of the carbonate component decreases and at 500 K no carbonates are left on the surface.…”

Section: Apxps Study Of Co Oxidation On Ag(100)-supported Co Oxide Filmsmentioning

confidence: 90%

The SPECIES beamline at the MAX IV Laboratory: a facility for soft X-ray RIXS and APXPS

et al. 2017

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SPECIES is an undulator-based soft X-ray beamline that replaced the old I511 beamline at the MAX II storage ring. SPECIES is aimed at high-resolution ambient-pressure X-ray photoelectron spectroscopy (APXPS), near-edge X-ray absorption fine-structure (NEXAFS), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) experiments. The beamline has two branches that use a common elliptically polarizing undulator and monochromator. The beam is switched between the two branches by changing the focusing optics after the monochromator. Both branches have separate exit slits, refocusing optics and dedicated permanent endstations. This allows very fast switching between two types of experiments and offers a unique combination of the surface-sensitive XPS and bulk-sensitive RIXS techniques both in UHV and at elevated ambient-pressure conditions on a single beamline. Another unique property of the beamline is that it reaches energies down to approximately 27 eV, which is not obtainable on other current APXPS beamlines. This allows, for instance, valence band studies under ambient-pressure conditions. In this article the main properties and performance of the beamline are presented, together with selected showcase experiments performed on the new setup.

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Adsorption and Activation of CO on Co₃O₄(111) Thin Films

Cited by 74 publications

References 63 publications

Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

The SPECIES beamline at the MAX IV Laboratory: a facility for soft X-ray RIXS and APXPS

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Adsorption and Activation of CO on Co3O4(111) Thin Films

Cited by 74 publications

References 63 publications

Thermal evolution of cobalt deposits on Co3O4(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

Thermal evolution of cobalt deposits on Co3O4(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

A multi-technique study of CO2 adsorption on Fe3O4 magnetite

The SPECIES beamline at the MAX IV Laboratory: a facility for soft X-ray RIXS and APXPS

Contact Info

Product

Resources

About

Adsorption and Activation of CO on Co₃O₄(111) Thin Films

Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles

Thermal evolution of cobalt deposits on Co₃O₄(111): atomically dispersed cobalt, two-dimensional CoO islands, and metallic Co nanoparticles