Laterally nanostructured cobalt oxide films on Ir(100)

Gubo, Matthias; Hammer, Lutz; Heinz, K.

doi:10.1103/physrevb.85.113402

Cited by 2 publications

(12 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…cannot only be inferred from the still hexagonal appearance of the LEED pattern. Also the inclination angle of about 55 • for the facets-as derived from the path of LEED spot with energy [45]-corresponds exactly to the angle between (100) and (111) lattice planes in a cubic crystal (54.7 • ). This means that the (111) termination towards the Ir(100) substrate is indeed a ground state feature of the film.…”

Section: Stability Of the (111) Surface And Interface Terminationmentioning

confidence: 68%

“…This From the energies where it intersects the integer order spots, the angle of the facet against the surface can be calculated. From that a (100) orientation of the facets results [45].…”

Section: Stability Of the (111) Surface And Interface Terminationmentioning

confidence: 99%

“…The quantity a is the surface parallel lattice parameter (2.715 Å) of Ir(100)-(1 × 1). [81]. 5-fold periodicity on a now (1 × 1)-structured substrate [12] (see figure 1(a)).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

Heinz

Hammer

2013

J. Phys.: Condens. Matter

132

View full text Add to dashboard Cite

Epitaxial cobalt oxide films on Ir(100) exhibit a rich scenario of different structural phases which are reviewed in this paper. The great majority of phases could be, as a rare case, crystallographically described by the joint application of atomically resolved STM and quantitative LEED, whereby structural surprises were more the rule than the exception. So, the oxide grows in the polar (111) orientation for both the Co3O4 and CoO stoichiometry on the bare Ir substrate in spite of the latter's square symmetry. Moreover, the film orientation can be tuned to non-polar (100) growth when one or several pseudomorphic Co layers are introduced as an interface between oxide and Ir substrate. By using the nanostructured Ir(100)-(5 × 1)-H phase as a template a nanostructured Co film can be formed whose oxidation leads to a nanostructured oxide. The nominally polar films circumvent the polarity problem by appropriate surface terminations. That of CoO(111) is, again as a surprise, realized by a switch from rocksalt-type to wurtzite-type stacking near the surface, by which the latter becomes metallic. The stepwise oxidation of a pseudomorphic Co layer on the bare Ir substrate leads to the sequential formation of rocksalt-type tetrahedral Co-O building blocks (with intermediate BN-type blocks) whereby the Co species more and more assume positions determined by the inner-oxidic binding.

show abstract

Section: Stability Of the (111) Surface And Interface Terminationmentioning

confidence: 68%

“…This From the energies where it intersects the integer order spots, the angle of the facet against the surface can be calculated. From that a (100) orientation of the facets results [45].…”

Section: Stability Of the (111) Surface And Interface Terminationmentioning

confidence: 99%

See 1 more Smart Citation

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

Heinz

Hammer

2013

J. Phys.: Condens. Matter

132

View full text Add to dashboard Cite

show abstract

“…33,34 Here, various other factors were considered, in particular the presence of oxygen vacancies and surface Co 2+ ions. [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. 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.…”

Section: Introductionmentioning

confidence: 99%

“…[35][36][37] We take advantage of the fact that a variety of well-ordered Co 3 O 4 and CoO films can be grown on Ir(100). [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. Over the last years many of these structures have been characterized in great detail using STM and LEED I-V analysis.…”

Section: Introductionmentioning

confidence: 99%

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.

View full text Add to dashboard Cite

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.

show abstract

Laterally nanostructured cobalt oxide films on Ir(100)

Cited by 2 publications

References 22 publications

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

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

Contact Info

Product

Resources

About

Laterally nanostructured cobalt oxide films on Ir(100)

Cited by 2 publications

References 22 publications

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

Epitaxial cobalt oxide films on Ir(100)—the importance of crystallographic analyses

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

Contact Info

Product

Resources

About

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