Influence of surface atomic structure demonstrated on oxygen incorporation mechanism at a model perovskite oxide

Riva, Michele; Kubicek, Markus; Hao, Xianfeng; Franceschi, Giada; Gerhold, Stefan; Schmid, Michael; Hutter, Herbert; Fleig, Jürgen; Franchini, Cesare; Yildiz, Bilge; Diebold, Ulrike

doi:10.1038/s41467-018-05685-5

Cited by 62 publications

(57 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the low oxygen pressure can create residual oxygen vacancies in the oxide that are generally unwanted. Further studies, for example, by spatially‐tracking 18 O isotopes using mass spectrometry could be helpful in this regard . Innovative concepts for minimizing unwanted interface layers that were implemented by the high‐ k dielectrics community may be useful for epitaxial oxides as well…”

Section: Discussionmentioning

confidence: 99%

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Kumah

Ngai

Kornblum

2019

Adv Funct Materials

View full text Add to dashboard Cite

Functional oxides are an untapped resource for futuristic devices and functionalities. These functionalities can range from high temperature superconductivity to multiferroicity and novel catalytic schemes. The most prominent route for transforming these ideas from a single device in the lab to practical technologies is by integration with semiconductors. Moreover, coupling oxides with semiconductors can herald new and unexpected functionalities that exist in neither of the individual materials. Therefore, oxide epitaxy on semiconductors provides a materials platform for novel device technologies. As oxides and semiconductors exhibit properties that are complementary to one another, epitaxial heterostructures comprised of the two are uniquely poised to deliver rich functionalities. This review discusses recent advancements in the growth of epitaxial oxides on semiconductors, and the electronic and physical structure of their interfaces. Leaning on these fundamentals and practicalities, the material behavior and functionality of semiconductor-oxide heterostructures is discussed, and their potential as device building blocks is highlighted. The culmination of this discussion is a review of recent advances in the development of prototype devices based on semiconductor-oxide heterostructures, in areas ranging from silicon photonics to photocatalysis. This overview is intended to stimulate ideas for new concepts of functional devices and lay the groundwork for their realization.

show abstract

Section: Discussionmentioning

confidence: 99%

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Kumah

Ngai

Kornblum

2019

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

“…For the purpose of the calculations, it was assumed that the efficiency of the process is constant and does not change with the increasing oxygen content. In that case, since oxygen incorporation and transport are the limiting steps of the process [27][28][29], again, the decreased efficiency (for materials with a higher Mn content) cannot be assigned only to their deteriorated total conductivity [14,30], but rather to the shift of voltage values toward the oxygen evolution reaction, which occurs for samples with higher Mn content ( Figure 1). As a result, a larger part of the flowing charge is consumed for the production of gaseous oxygen, and thereby, the efficiency of the electrochemical oxidation decreases.…”

Section: Electrochemical Oxidation Of Smbaco 15 Mn 05 O 5+δmentioning

confidence: 99%

Peculiar Properties of Electrochemically Oxidized SmBaCo2−xMnxO5+δ (x = 0; 0.5 and 1) A-Site Ordered Perovskites

2020

View full text Add to dashboard Cite

Fully-stoichiometric SmBaCo2-xMnxO6 oxides (x = 0, 0.5, 1) were obtained through the electrochemical oxidation method performed in 1 M KOH solution from starting materials having close to equilibrium oxygen content. Cycling voltammetry scans allow us to recognize the voltage range (0.3–0.55 V vs. Hg/HgO electrode) for which electrochemical oxidation occurs with high efficiency. In a similarly performed galvanostatic experiment, the value of the stabilized voltage recorded during the oxidation increased with higher Mn content, which seems to relate to the electronic structure of the compounds. Results of the iodometric titration and thermogravimetric analysis prove that the proposed technique allows for an increase in the oxygen content in SmBaCo2-xMnxO5+δ materials to values close to 6 (δ ≈ 1). While the expected significant enhancement of the total conductivity was observed for the oxidized samples, surprisingly, their crystal structure only underwent slight modification. This can be interpreted as due to the unique nature of the oxygen intercalation process at room temperature.

show abstract

“…Mixed ionic and electronic conductors (MIECs) from the perovskite family, such as La 1 (LSCF) are popular materials used as solid oxide fuel cell (SOFC) including LSM, the surface structure and composition likely plays a major role in determining the activity of ORR [37]. Tailoring the surface properties of these materials, however, is a major challenge that can be overcome only with more understanding of how their surfaces respond to stimuli from the environment.…”

Section: Introductionmentioning

confidence: 99%

Polar or not polar? The interplay between reconstruction, Sr enrichment, and reduction at the La0.75Sr0.25MnO3 (001) surface

Heß

Yildiz

2020

Phys. Rev. Materials

Self Cite

View full text Add to dashboard Cite

Perovskite oxides used in heterogeneous catalysis and electrocatalysis are tuned by substitutional doping. Sr-doped LaMnO 3 is a popular choice of electrode material for electrochemical energy conversion. At elevated temperatures, relevant to solid oxide fuel or electrolysis cells, Sr enriches at the surface, which leads to fast degradation of the oxygen exchange activity at the surface. In this work, we investigate the effect of oxygen partial pressure p(O 2) and temperature on Sr segregation at the La 0.75 Sr 0.25 MnO 3 (001) (LSM25) surface by ab initio thermodynamics calculations, taking into account different terminations and point defects Sr La , V •• O , V Mn , V La , O ad , as well as associated defects of the type [V •• O − V cation ]. This model of the LSM25(001) surface addresses the connection between point defects and surface stability and makes quantitative predictions about the surface termination and Sr enrichment. Our results indicate that the MnO 2 termination is stable under oxidizing conditions, while a partially covering SrO termination on MnO 2 is stable for reaction conditions between 1000 and 1400 K and effective oxygen partial pressures between 10 −11 bar and 0.1 bar relevant to solid oxide fuel cell (SOFC) cathodes. Under more reducing conditions, we find that Sr is enriched at the surface regardless of surface termination. This trend is a direct consequence of the increased formation of positively charged oxygen vacancies at the surface, and this conclusion holds regardless of which surface termination is assumed. The partial SrO termination is exceptionally stable under SOFC cathode conditions because it minimizes the surface dipole density, while all the defect-free terminations of LSM25(001) are unstable due to surface polarity. This newly proposed termination leaves both Sr, as well as Mn and O sites of the MnO 2 layer exposed at the surface and available for interaction with the gas phase. We propose that the LSM25(001) surface may consist of coexisting (La,Sr)O and MnO 2 domains under SOFC cathode conditions, and we propose to include such a micropatterned surface in the future discussion of the active site in the oxygen reduction reaction.

show abstract

Influence of surface atomic structure demonstrated on oxygen incorporation mechanism at a model perovskite oxide

Cited by 62 publications

References 55 publications

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Peculiar Properties of Electrochemically Oxidized SmBaCo2−xMnxO5+δ (x = 0; 0.5 and 1) A-Site Ordered Perovskites

Polar or not polar? The interplay between reconstruction, Sr enrichment, and reduction at the La0.75Sr0.25MnO3 (001) surface

Contact Info

Product

Resources

About