---
_id: '64182'
abstract:
- lang: eng
text: Overcoming the slow kinetics of the oxygen evolution reaction at the anode
is a key challenge for the production of hydrogen via electrolysis. This reaction
operates at very positive potentials, where the electrocatalyst is exposed to
highly oxidative conditions and prone to potential-dependent transformation of
the near-surface region. While substantial evidence for such surface restructuring
exists, its extent and relevance for the catalyst’s activity are unclear. We address
this topic for the case of Co3O4, one of the best-known electrocatalysts exhibiting
surface restructuring, by studies of epitaxial (111)-ordered electrodeposited
films with combined operando X-ray surface diffraction and absorption spectroscopy,
electrochemical impedance spectroscopy, and electrochemical measurements on rotating
disk electrodes. Comparison of the as-prepared and annealed state of the same
samples, which both are stable even under long-term oxygen evolution conditions,
provides clear insight into the role of surface defects. Our results show that
defect-free annealed Co3O4(111) surfaces are structurally stable over a wide potential
range and hydroxylate via adsorption at surface oxygen and Co sites. Potential-induced
surface restructuring of the Co3O4 lattice occurs only in the presence of surface
defects, leading to the formation of the well-known nanometer-thick oxyhydroxide
skin layer. The presence of this skin layer promotes oxygen evolution at low overpotentials
but results in higher Tafel slopes. As a result, highly ordered Co3O4(111) surfaces
are more active at high current densities than defective Co3O4 surfaces that undergo
surface restructuring. These results highlight that strategies for catalyst surface
defect engineering need to be application-oriented.
article_number: acscatal.5c08785
article_type: original
author:
- first_name: Carl Hendric
full_name: Scharf, Carl Hendric
last_name: Scharf
- first_name: Alex
full_name: Chandraraj, Alex
last_name: Chandraraj
- first_name: Konrad
full_name: Dyk, Konrad
last_name: Dyk
- first_name: Felix
full_name: Stebner, Felix
last_name: Stebner
- first_name: Sören
full_name: Lepin, Sören
last_name: Lepin
- first_name: Jing
full_name: Tian, Jing
last_name: Tian
- first_name: Laila
full_name: El Bergmi Byaz, Laila
last_name: El Bergmi Byaz
- first_name: Jochim
full_name: Stettner, Jochim
last_name: Stettner
- first_name: Christian
full_name: Leppin, Christian
id: '117722'
last_name: Leppin
- first_name: Anastasiia
full_name: Kotova, Anastasiia
last_name: Kotova
- first_name: Sebastian
full_name: Reinke, Sebastian
id: '117727'
last_name: Reinke
- first_name: Julia
full_name: Linnemann, Julia
id: '116779'
last_name: Linnemann
orcid: 0000-0001-6883-5424
- first_name: Fouad
full_name: Maroun, Fouad
last_name: Maroun
- first_name: Olaf M.
full_name: Magnussen, Olaf M.
last_name: Magnussen
citation:
ama: Scharf CH, Chandraraj A, Dyk K, et al. Role of Defects in Reversible Surface
Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts.
ACS Catalysis. Published online 2026. doi:10.1021/acscatal.5c08785
apa: Scharf, C. H., Chandraraj, A., Dyk, K., Stebner, F., Lepin, S., Tian, J., El
Bergmi Byaz, L., Stettner, J., Leppin, C., Kotova, A., Reinke, S., Linnemann,
J., Maroun, F., & Magnussen, O. M. (2026). Role of Defects in Reversible Surface
Restructuring and Activity of Co3O4 Oxygen Evolution Electrocatalysts.
ACS Catalysis, Article acscatal.5c08785. https://doi.org/10.1021/acscatal.5c08785
bibtex: '@article{Scharf_Chandraraj_Dyk_Stebner_Lepin_Tian_El Bergmi Byaz_Stettner_Leppin_Kotova_et
al._2026, title={Role of Defects in Reversible Surface Restructuring and Activity
of Co3O4 Oxygen Evolution Electrocatalysts}, DOI={10.1021/acscatal.5c08785},
number={acscatal.5c08785}, journal={ACS Catalysis}, publisher={American Chemical
Society (ACS)}, author={Scharf, Carl Hendric and Chandraraj, Alex and Dyk, Konrad
and Stebner, Felix and Lepin, Sören and Tian, Jing and El Bergmi Byaz, Laila and
Stettner, Jochim and Leppin, Christian and Kotova, Anastasiia and et al.}, year={2026}
}'
chicago: Scharf, Carl Hendric, Alex Chandraraj, Konrad Dyk, Felix Stebner, Sören
Lepin, Jing Tian, Laila El Bergmi Byaz, et al. “Role of Defects in Reversible
Surface Restructuring and Activity of Co3O4 Oxygen Evolution
Electrocatalysts.” ACS Catalysis, 2026. https://doi.org/10.1021/acscatal.5c08785.
ieee: 'C. H. Scharf et al., “Role of Defects in Reversible Surface Restructuring
and Activity of Co3O4 Oxygen Evolution Electrocatalysts,”
ACS Catalysis, Art. no. acscatal.5c08785, 2026, doi: 10.1021/acscatal.5c08785.'
mla: Scharf, Carl Hendric, et al. “Role of Defects in Reversible Surface Restructuring
and Activity of Co3O4 Oxygen Evolution Electrocatalysts.”
ACS Catalysis, acscatal.5c08785, American Chemical Society (ACS), 2026,
doi:10.1021/acscatal.5c08785.
short: C.H. Scharf, A. Chandraraj, K. Dyk, F. Stebner, S. Lepin, J. Tian, L. El
Bergmi Byaz, J. Stettner, C. Leppin, A. Kotova, S. Reinke, J. Linnemann, F. Maroun,
O.M. Magnussen, ACS Catalysis (2026).
date_created: 2026-02-16T14:22:15Z
date_updated: 2026-02-16T14:25:00Z
department:
- _id: '985'
doi: 10.1021/acscatal.5c08785
keyword:
- electrocatalysis
- oxygen evolution reaction
- cobalt spinel
- operando characterization
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://pubs.acs.org/doi/10.1021/acscatal.5c08785
oa: '1'
publication: ACS Catalysis
publication_identifier:
issn:
- 2155-5435
- 2155-5435
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Role of Defects in Reversible Surface Restructuring and Activity of Co3O4
Oxygen Evolution Electrocatalysts
type: journal_article
user_id: '116779'
year: '2026'
...
---
_id: '63754'
abstract:
- lang: eng
text: Data spaces are receiving an emerging interest in Information Systems Research
and industry practice. They are central to many European research initiatives
and shape the data economy in Industry 4.0. Generally, they aim to create secure
environments for cross-organizational data management and sharing. Currently,
there is considerable interest in developing new data spaces in Industry 4.0,
also accelerated through regulatory changes. However, key questions about what
precisely characterizes a data space in Industry 4.0 remain unresolved. Against
this backdrop, we build a taxonomy of data spaces in the Industry 4.0 context.
We identified nine distinctive dimensions and 40 corresponding characteristics
among the 19 data spaces analyzed. The taxonomy enables clearer classification
and nomenclature of data spaces in this context. This short paper will ignite
planned further research on data spaces in Industry 4.0 and contribute to a conceptualization
of a taxonomic theory for interested researchers.
author:
- first_name: Oliver
full_name: Werth, Oliver
last_name: Werth
- first_name: Christian
full_name: Koldewey, Christian
id: '43136'
last_name: Koldewey
orcid: https://orcid.org/0000-0001-7992-6399
- first_name: Mathias
full_name: Uslar, Mathias
last_name: Uslar
- first_name: Julian
full_name: Zerbin, Julian
id: '51711'
last_name: Zerbin
citation:
ama: 'Werth O, Koldewey C, Uslar M, Zerbin J. What Characterizes Data Spaces in
Industry 4.0? Towards a Better Understanding. In: Lecture Notes in Business
Information Processing. Springer Nature Switzerland; 2026. doi:10.1007/978-3-032-14518-5_3'
apa: Werth, O., Koldewey, C., Uslar, M., & Zerbin, J. (2026). What Characterizes
Data Spaces in Industry 4.0? Towards a Better Understanding. Lecture Notes
in Business Information Processing. 16th International Conference on Software
Business (ICSOB 2025), Stuttgart, Germany. https://doi.org/10.1007/978-3-032-14518-5_3
bibtex: '@inproceedings{Werth_Koldewey_Uslar_Zerbin_2026, place={Cham}, title={What
Characterizes Data Spaces in Industry 4.0? Towards a Better Understanding}, DOI={10.1007/978-3-032-14518-5_3},
booktitle={Lecture Notes in Business Information Processing}, publisher={Springer
Nature Switzerland}, author={Werth, Oliver and Koldewey, Christian and Uslar,
Mathias and Zerbin, Julian}, year={2026} }'
chicago: 'Werth, Oliver, Christian Koldewey, Mathias Uslar, and Julian Zerbin. “What
Characterizes Data Spaces in Industry 4.0? Towards a Better Understanding.” In
Lecture Notes in Business Information Processing. Cham: Springer Nature
Switzerland, 2026. https://doi.org/10.1007/978-3-032-14518-5_3.'
ieee: 'O. Werth, C. Koldewey, M. Uslar, and J. Zerbin, “What Characterizes Data
Spaces in Industry 4.0? Towards a Better Understanding,” presented at the 16th
International Conference on Software Business (ICSOB 2025), Stuttgart, Germany,
2026, doi: 10.1007/978-3-032-14518-5_3.'
mla: Werth, Oliver, et al. “What Characterizes Data Spaces in Industry 4.0? Towards
a Better Understanding.” Lecture Notes in Business Information Processing,
Springer Nature Switzerland, 2026, doi:10.1007/978-3-032-14518-5_3.
short: 'O. Werth, C. Koldewey, M. Uslar, J. Zerbin, in: Lecture Notes in Business
Information Processing, Springer Nature Switzerland, Cham, 2026.'
conference:
end_date: 2025-11-26
location: Stuttgart, Germany
name: 16th International Conference on Software Business (ICSOB 2025)
start_date: 2025-11-24
date_created: 2026-01-27T11:56:10Z
date_updated: 2026-03-18T07:12:49Z
department:
- _id: '563'
doi: 10.1007/978-3-032-14518-5_3
keyword:
- Industry 4.0
- Taxonomy
- Data spaces
- Characterization
language:
- iso: eng
place: Cham
publication: Lecture Notes in Business Information Processing
publication_identifier:
isbn:
- '9783032145178'
- '9783032145185'
issn:
- 1865-1348
- 1865-1356
publication_status: published
publisher: Springer Nature Switzerland
quality_controlled: '1'
status: public
title: What Characterizes Data Spaces in Industry 4.0? Towards a Better Understanding
type: conference
user_id: '51711'
year: '2026'
...
---
_id: '61014'
abstract:
- lang: eng
text: 'To obtain a more comprehensive understanding of the specific properties
of complex-shaped technical aerosols—such as partially sintered aggregates formed
in combustion processes or structured particles resulting from complex synthesis
processes—it is essential to measure more than a single equivalent size. This
study examines a novel method for determining a two-dimensional distribution of
two distinct particle properties within the size range from 50nm to 1000nm: the
Centrifugal Differential Mobility Analyzer (CDMA). The CDMA enables the simultaneous
measurement of both mobility and Stokes equivalent diameters, providing a detailed
two-dimensional particle property distribution. This, in turn, allows for the
extraction of shape-related information, which is essential for characterizing
particles in terms of their chemical composition, reactivity, and other physicochemical
properties. This paper presents a detailed evaluation of a first CDMA prototype.
First, CFD simulations of the flow field within the classifier are presented in
order to assess and understand non-idealities arising from the exact geometry.
Subsequently, the transfer function is evaluated by particle trajectory calculations
based on the simulated flow field. It can be demonstrated that the simulated transfer
functions agree quite well with transfer functions derived from streamlines of
an ideal flow field, indicating that the non-idealities in the classifying region
are almost negligible in their effect on the classification result. An experimental
determination of the transfer function shows additional effects not covered by
the previous simulations, like broadening by diffusion and losses due to diffusion
and precipitation within the in- and outlet of the classifier. Finally, the determined
transfer functions are used to determine the full two-dimensional distribution
with regard to the mobility and Stokes equivalent diameter of real aerosols, like
spherical particles and aggregates at different sintering stages, respectively.'
article_number: '11'
article_type: original
author:
- first_name: Torben Norbert
full_name: Rüther, Torben Norbert
last_name: Rüther
- first_name: Sebastian
full_name: Gröne, Sebastian
last_name: Gröne
- first_name: Christopher
full_name: Dechert, Christopher
last_name: Dechert
- first_name: Hans-Joachim
full_name: Schmid, Hans-Joachim
id: '464'
last_name: Schmid
orcid: 000-0001-8590-1921
citation:
ama: Rüther TN, Gröne S, Dechert C, Schmid H-J. Centrifugal Differential Mobility
Analysis—Validation and First Two-Dimensional Measurements. Powders. 2025;4(2).
doi:10.3390/powders4020011
apa: Rüther, T. N., Gröne, S., Dechert, C., & Schmid, H.-J. (2025). Centrifugal
Differential Mobility Analysis—Validation and First Two-Dimensional Measurements.
Powders, 4(2), Article 11. https://doi.org/10.3390/powders4020011
bibtex: '@article{Rüther_Gröne_Dechert_Schmid_2025, title={Centrifugal Differential
Mobility Analysis—Validation and First Two-Dimensional Measurements}, volume={4},
DOI={10.3390/powders4020011},
number={211}, journal={Powders}, publisher={MDPI AG}, author={Rüther, Torben Norbert
and Gröne, Sebastian and Dechert, Christopher and Schmid, Hans-Joachim}, year={2025}
}'
chicago: Rüther, Torben Norbert, Sebastian Gröne, Christopher Dechert, and Hans-Joachim
Schmid. “Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional
Measurements.” Powders 4, no. 2 (2025). https://doi.org/10.3390/powders4020011.
ieee: 'T. N. Rüther, S. Gröne, C. Dechert, and H.-J. Schmid, “Centrifugal Differential
Mobility Analysis—Validation and First Two-Dimensional Measurements,” Powders,
vol. 4, no. 2, Art. no. 11, 2025, doi: 10.3390/powders4020011.'
mla: Rüther, Torben Norbert, et al. “Centrifugal Differential Mobility Analysis—Validation
and First Two-Dimensional Measurements.” Powders, vol. 4, no. 2, 11, MDPI
AG, 2025, doi:10.3390/powders4020011.
short: T.N. Rüther, S. Gröne, C. Dechert, H.-J. Schmid, Powders 4 (2025).
date_created: 2025-08-25T16:10:45Z
date_updated: 2025-08-25T16:15:41Z
doi: 10.3390/powders4020011
funded_apc: '1'
intvolume: ' 4'
issue: '2'
keyword:
- centrifugal differential mobility analysis
- 2D-measurement
- particle characterization
- moving reference frame CFD-simulation
- transfer function
language:
- iso: eng
publication: Powders
publication_identifier:
issn:
- 2674-0516
publication_status: published
publisher: MDPI AG
quality_controlled: '1'
status: public
title: Centrifugal Differential Mobility Analysis—Validation and First Two-Dimensional
Measurements
type: journal_article
user_id: '464'
volume: 4
year: '2025'
...
---
_id: '61982'
abstract:
- lang: eng
text: Doped Co3O4 nanoparticles are investigated via spectro-electrochemistry in
the (pre-) oxygen evolution reaction (OER) regime by tracing the absorption signal
of the Co3+ d–d transition under applied bias for getting insight into the catalysts
activation and the formation of catalytically active phases. In the low potential
regime up to 1.37 VRHE, a rise in the optical absorption signal of the [Co3+]oct
d–d transition is observed and attributed to a structural change from [Co2+]tet
to [Co3+]oct due to an electrochemically induced surface restructuring with water.
For applied potentials higher than 1.37 VRHE an overall offset of the absorption
spectra in the UV–vis range, equivalent to a darkening of the materials is detected.
This is attributed to the formation of a CoOx(OH)y skin layer as supported by
high-energy X-ray diffraction (HE-XRD) measurements. We found that the kinetics
of the Co3+ states are heavily influenced by the type of dopant with V-doped Co3O4
exhibiting stable Co3+ states (>20 min) while the Mn-doped Co3O4 Co3+ states reduce
within 36 s under reductive bias. We conclude that doping Co3O4 with transition
metals affects the formation and potential-dependent thickness of the CoOx(OH)y
skin layer as the catalytically active phase and the formation of long-time stable
surface Co3+ states after activation in the first OER cycle.
article_type: original
author:
- first_name: L.
full_name: Kampermann, L.
last_name: Kampermann
- first_name: J.
full_name: Klein, J.
last_name: Klein
- first_name: T.
full_name: Wagner, T.
last_name: Wagner
- first_name: A.
full_name: Kotova, A.
last_name: Kotova
- first_name: C.
full_name: Placke-Yan, C.
last_name: Placke-Yan
- first_name: A.
full_name: Yasar, A.
last_name: Yasar
- first_name: L.
full_name: Jacobse, L.
last_name: Jacobse
- first_name: S.
full_name: Lasagna, S.
last_name: Lasagna
- first_name: Christian
full_name: Leppin, Christian
id: '117722'
last_name: Leppin
- first_name: S.
full_name: Schulz, S.
last_name: Schulz
- first_name: Julia
full_name: Linnemann, Julia
id: '116779'
last_name: Linnemann
orcid: 0000-0001-6883-5424
- first_name: A.
full_name: Bergmann, A.
last_name: Bergmann
- first_name: B.
full_name: Roldan Cuenya, B.
last_name: Roldan Cuenya
- first_name: G.
full_name: Bacher, G.
last_name: Bacher
citation:
ama: Kampermann L, Klein J, Wagner T, et al. Operando Analysis of the Pre-OER Activation
of Metal-Doped Co3O4 Nanoparticle Catalysts. ACS Catalysis.
2025;15(21):18391-18403. doi:10.1021/acscatal.5c03900
apa: Kampermann, L., Klein, J., Wagner, T., Kotova, A., Placke-Yan, C., Yasar, A.,
Jacobse, L., Lasagna, S., Leppin, C., Schulz, S., Linnemann, J., Bergmann, A.,
Roldan Cuenya, B., & Bacher, G. (2025). Operando Analysis of the Pre-OER Activation
of Metal-Doped Co3O4 Nanoparticle Catalysts. ACS Catalysis,
15(21), 18391–18403. https://doi.org/10.1021/acscatal.5c03900
bibtex: '@article{Kampermann_Klein_Wagner_Kotova_Placke-Yan_Yasar_Jacobse_Lasagna_Leppin_Schulz_et
al._2025, title={Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4
Nanoparticle Catalysts}, volume={15}, DOI={10.1021/acscatal.5c03900},
number={21}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)},
author={Kampermann, L. and Klein, J. and Wagner, T. and Kotova, A. and Placke-Yan,
C. and Yasar, A. and Jacobse, L. and Lasagna, S. and Leppin, Christian and Schulz,
S. and et al.}, year={2025}, pages={18391–18403} }'
chicago: 'Kampermann, L., J. Klein, T. Wagner, A. Kotova, C. Placke-Yan, A. Yasar,
L. Jacobse, et al. “Operando Analysis of the Pre-OER Activation of Metal-Doped
Co3O4 Nanoparticle Catalysts.” ACS Catalysis 15,
no. 21 (2025): 18391–403. https://doi.org/10.1021/acscatal.5c03900.'
ieee: 'L. Kampermann et al., “Operando Analysis of the Pre-OER Activation
of Metal-Doped Co3O4 Nanoparticle Catalysts,” ACS Catalysis,
vol. 15, no. 21, pp. 18391–18403, 2025, doi: 10.1021/acscatal.5c03900.'
mla: Kampermann, L., et al. “Operando Analysis of the Pre-OER Activation of Metal-Doped
Co3O4 Nanoparticle Catalysts.” ACS Catalysis, vol.
15, no. 21, American Chemical Society (ACS), 2025, pp. 18391–403, doi:10.1021/acscatal.5c03900.
short: L. Kampermann, J. Klein, T. Wagner, A. Kotova, C. Placke-Yan, A. Yasar, L.
Jacobse, S. Lasagna, C. Leppin, S. Schulz, J. Linnemann, A. Bergmann, B. Roldan
Cuenya, G. Bacher, ACS Catalysis 15 (2025) 18391–18403.
date_created: 2025-10-24T07:49:21Z
date_updated: 2025-12-07T17:15:53Z
department:
- _id: '985'
doi: 10.1021/acscatal.5c03900
intvolume: ' 15'
issue: '21'
keyword:
- electrocatalysis
- oxygen evolution reaction
- cobalt spinel
- operando characterization
- spectroelectrochemistry
language:
- iso: eng
page: 18391-18403
publication: ACS Catalysis
publication_identifier:
issn:
- 2155-5435
- 2155-5435
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Operando Analysis of the Pre-OER Activation of Metal-Doped Co3O4
Nanoparticle Catalysts
type: journal_article
user_id: '116779'
volume: 15
year: '2025'
...
---
_id: '43441'
abstract:
- lang: eng
text: "This paper reveals the 3D character of the intermetallic layer at the aluminum–steel
interface which pops\r\nup above the original sample surface during annealing.
Popping out of the intermetallics was proven using\r\natomic force microscopy.
The phase expands out of the plane due to the exothermic formation of the Al5Fe2\r\nphase
and the feasibility of surface diffusion. Milling by a focused ion beam enabled
the comparison of the\r\nchemical composition of the surface layer with the bulk
interface, showing no difference. The growth direction\r\nis both towards aluminum
and steel — the main diffusion flux is from aluminum towards steel, and the new\r\nintermetallic
phase emerges at the steel side. The shortage of Al atoms causes a shift of the
intermetallic as a\r\nwhole towards aluminum."
article_number: '112043'
article_type: original
author:
- first_name: Michaela
full_name: Šlapáková, Michaela
last_name: Šlapáková
- first_name: Barbora
full_name: Kihoulou, Barbora
last_name: Kihoulou
- first_name: Jozef
full_name: Veselý, Jozef
last_name: Veselý
- first_name: Peter
full_name: Minárik, Peter
last_name: Minárik
- first_name: Klaudia
full_name: Fekete, Klaudia
last_name: Fekete
- first_name: Michal
full_name: Knapek, Michal
last_name: Knapek
- first_name: Rostislav
full_name: Králík, Rostislav
last_name: Králík
- first_name: Olexandr
full_name: Grydin, Olexandr
id: '43822'
last_name: Grydin
- first_name: Mykhailo
full_name: Stolbchenko, Mykhailo
last_name: Stolbchenko
- first_name: Mirko
full_name: Schaper, Mirko
id: '43720'
last_name: Schaper
citation:
ama: Šlapáková M, Kihoulou B, Veselý J, et al. 3D-structure of intermetallic interface
layer in Al–steel clad material. Vacuum. 2023;212. doi:10.1016/j.vacuum.2023.112043
apa: Šlapáková, M., Kihoulou, B., Veselý, J., Minárik, P., Fekete, K., Knapek, M.,
Králík, R., Grydin, O., Stolbchenko, M., & Schaper, M. (2023). 3D-structure
of intermetallic interface layer in Al–steel clad material. Vacuum, 212,
Article 112043. https://doi.org/10.1016/j.vacuum.2023.112043
bibtex: '@article{Šlapáková_Kihoulou_Veselý_Minárik_Fekete_Knapek_Králík_Grydin_Stolbchenko_Schaper_2023,
title={3D-structure of intermetallic interface layer in Al–steel clad material},
volume={212}, DOI={10.1016/j.vacuum.2023.112043},
number={112043}, journal={Vacuum}, publisher={Elsevier BV}, author={Šlapáková,
Michaela and Kihoulou, Barbora and Veselý, Jozef and Minárik, Peter and Fekete,
Klaudia and Knapek, Michal and Králík, Rostislav and Grydin, Olexandr and Stolbchenko,
Mykhailo and Schaper, Mirko}, year={2023} }'
chicago: Šlapáková, Michaela, Barbora Kihoulou, Jozef Veselý, Peter Minárik, Klaudia
Fekete, Michal Knapek, Rostislav Králík, Olexandr Grydin, Mykhailo Stolbchenko,
and Mirko Schaper. “3D-Structure of Intermetallic Interface Layer in Al–Steel
Clad Material.” Vacuum 212 (2023). https://doi.org/10.1016/j.vacuum.2023.112043.
ieee: 'M. Šlapáková et al., “3D-structure of intermetallic interface layer
in Al–steel clad material,” Vacuum, vol. 212, Art. no. 112043, 2023, doi:
10.1016/j.vacuum.2023.112043.'
mla: Šlapáková, Michaela, et al. “3D-Structure of Intermetallic Interface Layer
in Al–Steel Clad Material.” Vacuum, vol. 212, 112043, Elsevier BV, 2023,
doi:10.1016/j.vacuum.2023.112043.
short: M. Šlapáková, B. Kihoulou, J. Veselý, P. Minárik, K. Fekete, M. Knapek, R.
Králík, O. Grydin, M. Stolbchenko, M. Schaper, Vacuum 212 (2023).
date_created: 2023-04-08T17:24:40Z
date_updated: 2023-06-01T14:22:15Z
department:
- _id: '158'
doi: 10.1016/j.vacuum.2023.112043
intvolume: ' 212'
keyword:
- Al-steel clad
- twin-roll casting
- 3D characterization
- atomic force microscopy
- diffusion direction
- surface growth
language:
- iso: eng
publication: Vacuum
publication_identifier:
issn:
- 0042-207X
publication_status: published
publisher: Elsevier BV
quality_controlled: '1'
status: public
title: 3D-structure of intermetallic interface layer in Al–steel clad material
type: journal_article
user_id: '43720'
volume: 212
year: '2023'
...
---
_id: '64045'
abstract:
- lang: eng
text: Abstract In this work, we report on an improved cell assembly of cylindrical
electrochemical cells for 23Na in-situ solid-state NMR (ssNMR) investigations.
The cell set-up is suitable for using powder electrode materials. Reproducibility
of our cell assembly is analyzed by preparing two cells containing hard carbon
(HC) powder as working electrode and sodium metal as reference electrode. Electrochemical
storage properties of HC powder electrode derived from carbonization of sustainable
cellulose are studied by ssNMR. 23Na in-situ ssNMR monitors the sodiation/desodiation
of a Na{\textbar}NaPF6{\textbar}HC cell (cell 1) over a period of 22?days, showing
high cell stability. After the galvanostatic process, the HC powder material is
investigated by high resolution 23Na ex-situ MAS NMR. The formation of ionic sodium
species in different chemical environments is obtained. Subsequently, a second
Na{\textbar}NaPF6{\textbar}HC cell (cell 2) is sodiated for 11?days achieving
a capacity of 220?mAh/g. 23Na ex-situ MAS NMR measurements of the HC powder material
extracted from this cell clearly indicate the presence of quasi-metallic sodium
species next to ionic sodium species. This observation of quasi-metallic sodium
species is discussed in terms of the achieved capacity of the cell as well as
of side reactions of sodium in this electrode material.
author:
- first_name: Edina
full_name: Šić, Edina
last_name: Šić
- first_name: Konstantin
full_name: Schutjajew, Konstantin
last_name: Schutjajew
- first_name: Ulrich
full_name: Haagen, Ulrich
last_name: Haagen
- first_name: Hergen
full_name: Breitzke, Hergen
last_name: Breitzke
- first_name: Martin
full_name: Oschatz, Martin
last_name: Oschatz
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: 'Šić E, Schutjajew K, Haagen U, et al. Electrochemical Sodium Storage in Hard
Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from
In-Situ and Ex-Situ Solid-State NMR. Chemsuschem. 2023;17:e202301300. doi:10.1002/cssc.202301300'
apa: 'Šić, E., Schutjajew, K., Haagen, U., Breitzke, H., Oschatz, M., Buntkowsky,
G., & Gutmann, T. (2023). Electrochemical Sodium Storage in Hard Carbon Powder
Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and
Ex-Situ Solid-State NMR. Chemsuschem, 17, e202301300. https://doi.org/10.1002/cssc.202301300'
bibtex: '@article{Šić_Schutjajew_Haagen_Breitzke_Oschatz_Buntkowsky_Gutmann_2023,
title={Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented
in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR},
volume={17}, DOI={10.1002/cssc.202301300},
journal={Chemsuschem}, publisher={John Wiley & Sons, Ltd}, author={Šić, Edina
and Schutjajew, Konstantin and Haagen, Ulrich and Breitzke, Hergen and Oschatz,
Martin and Buntkowsky, Gerd and Gutmann, Torsten}, year={2023}, pages={e202301300}
}'
chicago: 'Šić, Edina, Konstantin Schutjajew, Ulrich Haagen, Hergen Breitzke, Martin
Oschatz, Gerd Buntkowsky, and Torsten Gutmann. “Electrochemical Sodium Storage
in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights
from In-Situ and Ex-Situ Solid-State NMR.” Chemsuschem 17 (2023): e202301300.
https://doi.org/10.1002/cssc.202301300.'
ieee: 'E. Šić et al., “Electrochemical Sodium Storage in Hard Carbon Powder
Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and
Ex-Situ Solid-State NMR,” Chemsuschem, vol. 17, p. e202301300, 2023, doi:
10.1002/cssc.202301300.'
mla: 'Šić, Edina, et al. “Electrochemical Sodium Storage in Hard Carbon Powder Electrodes
Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State
NMR.” Chemsuschem, vol. 17, John Wiley & Sons, Ltd, 2023, p. e202301300,
doi:10.1002/cssc.202301300.'
short: E. Šić, K. Schutjajew, U. Haagen, H. Breitzke, M. Oschatz, G. Buntkowsky,
T. Gutmann, Chemsuschem 17 (2023) e202301300.
date_created: 2026-02-07T16:12:13Z
date_updated: 2026-02-17T16:13:10Z
doi: 10.1002/cssc.202301300
extern: '1'
intvolume: ' 17'
keyword:
- solid-state nmr
- hard carbon
- electrochemical cells
- in-situ characterization
- sodium
language:
- iso: eng
page: e202301300
publication: Chemsuschem
publication_identifier:
issn:
- 1864-5631
publisher: John Wiley & Sons, Ltd
status: public
title: 'Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented
in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR'
type: journal_article
user_id: '100715'
volume: 17
year: '2023'
...
---
_id: '63920'
abstract:
- lang: eng
text: Coordinatively unsaturated sites (CUS) present a key feature of alumina based
catalysts as they are believed to act as Lewis-acid sites in heterogeneously catalyzed
reactions. In the present study, the direct observation of active species on a
fluoride-doped aluminum oxide catalyst is demonstrated. This new fluoride-doped
aluminum oxide exhibits strong Lewis-acid sites and superior catalytic activity
as compared to gamma-Al2O3. To emphasize the labile state of Lewis-acid sites,
two distinctive states of the catalysts surface are addressed using H-1-Al-27
cross polarization (CP) MAS NMR. On the one hand, the highly dehydrated and active
state after calcination at 700 degrees C and on the other hand the rehydrated
and catalytically inactive surface (produced by contact to air) are probed. These
experiments revealed the presence of significant amounts of coordinatively unsaturated
sites in the form of 4-and 5-fold coordinated Al-sites on the highly dehydrated
surface. In contrast to this, the rehydrated sample exhibited a severely restructured
surface caused by the chemisorption of H2O which is ’constituted in a manner that
was proposed in earlier models for gamma-Al2O3 surfaces.
author:
- first_name: L.
full_name: Ahrem, L.
last_name: Ahrem
- first_name: G.
full_name: Scholz, G.
last_name: Scholz
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: B.
full_name: Calvo, B.
last_name: Calvo
- first_name: G.
full_name: Buntkowsky, G.
last_name: Buntkowsky
- first_name: E.
full_name: Kemnitz, E.
last_name: Kemnitz
citation:
ama: Ahrem L, Scholz G, Gutmann T, Calvo B, Buntkowsky G, Kemnitz E. Direct Observation
of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped Alumina
Catalyst. Journal of Physical Chemistry C. 2017;121(22):12206–12213. doi:10.1021/acs.jpcc.7b02535
apa: Ahrem, L., Scholz, G., Gutmann, T., Calvo, B., Buntkowsky, G., & Kemnitz,
E. (2017). Direct Observation of Coordinatively Unsaturated Sites on the Surface
of a Fluoride-Doped Alumina Catalyst. Journal of Physical Chemistry C,
121(22), 12206–12213. https://doi.org/10.1021/acs.jpcc.7b02535
bibtex: '@article{Ahrem_Scholz_Gutmann_Calvo_Buntkowsky_Kemnitz_2017, title={Direct
Observation of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped
Alumina Catalyst}, volume={121}, DOI={10.1021/acs.jpcc.7b02535},
number={22}, journal={Journal of Physical Chemistry C}, author={Ahrem, L. and
Scholz, G. and Gutmann, Torsten and Calvo, B. and Buntkowsky, G. and Kemnitz,
E.}, year={2017}, pages={12206–12213} }'
chicago: 'Ahrem, L., G. Scholz, Torsten Gutmann, B. Calvo, G. Buntkowsky, and E.
Kemnitz. “Direct Observation of Coordinatively Unsaturated Sites on the Surface
of a Fluoride-Doped Alumina Catalyst.” Journal of Physical Chemistry C
121, no. 22 (2017): 12206–12213. https://doi.org/10.1021/acs.jpcc.7b02535.'
ieee: 'L. Ahrem, G. Scholz, T. Gutmann, B. Calvo, G. Buntkowsky, and E. Kemnitz,
“Direct Observation of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped
Alumina Catalyst,” Journal of Physical Chemistry C, vol. 121, no. 22, pp.
12206–12213, 2017, doi: 10.1021/acs.jpcc.7b02535.'
mla: Ahrem, L., et al. “Direct Observation of Coordinatively Unsaturated Sites on
the Surface of a Fluoride-Doped Alumina Catalyst.” Journal of Physical Chemistry
C, vol. 121, no. 22, 2017, pp. 12206–12213, doi:10.1021/acs.jpcc.7b02535.
short: L. Ahrem, G. Scholz, T. Gutmann, B. Calvo, G. Buntkowsky, E. Kemnitz, Journal
of Physical Chemistry C 121 (2017) 12206–12213.
date_created: 2026-02-07T08:56:18Z
date_updated: 2026-02-17T16:19:24Z
doi: 10.1021/acs.jpcc.7b02535
extern: '1'
intvolume: ' 121'
issue: '22'
keyword:
- al-27 nmr
- characterization
- Chemistry
- cross-polarization
- dynamic nuclear-polarization
- eta-alumina
- gamma-alumina
- hydroxy fluorides
- ions
- Materials Science
- pentacoordinated al3+
- Science & Technology - Other Topics
- solid-state nmr
- spectroscopic
- structural insights
language:
- iso: eng
page: 12206–12213
publication: Journal of Physical Chemistry C
publication_identifier:
issn:
- 1932-7447
status: public
title: Direct Observation of Coordinatively Unsaturated Sites on the Surface of a
Fluoride-Doped Alumina Catalyst
type: journal_article
user_id: '100715'
volume: 121
year: '2017'
...
---
_id: '6551'
author:
- first_name: Fabian
full_name: Bause, Fabian
last_name: Bause
- first_name: Jens
full_name: Rautenberg, Jens
last_name: Rautenberg
- first_name: Nadine
full_name: Feldmann, Nadine
id: '23082'
last_name: Feldmann
- first_name: Manuel
full_name: Webersen, Manuel
id: '11289'
last_name: Webersen
orcid: 0000-0001-6411-4232
- first_name: Leander
full_name: Claes, Leander
id: '11829'
last_name: Claes
orcid: 0000-0002-4393-268X
- first_name: Hauke
full_name: Gravenkamp, Hauke
last_name: Gravenkamp
- first_name: Bernd
full_name: Henning, Bernd
id: '213'
last_name: Henning
citation:
ama: Bause F, Rautenberg J, Feldmann N, et al. Ultrasonic transmission measurements
in the characterization of viscoelasticity utilizing polymeric waveguides. Measurement
Science and Technology. 2016;27(10). doi:10.1088/0957-0233/27/10/105601
apa: Bause, F., Rautenberg, J., Feldmann, N., Webersen, M., Claes, L., Gravenkamp,
H., & Henning, B. (2016). Ultrasonic transmission measurements in the characterization
of viscoelasticity utilizing polymeric waveguides. Measurement Science and
Technology, 27(10). https://doi.org/10.1088/0957-0233/27/10/105601
bibtex: '@article{Bause_Rautenberg_Feldmann_Webersen_Claes_Gravenkamp_Henning_2016,
title={Ultrasonic transmission measurements in the characterization of viscoelasticity
utilizing polymeric waveguides}, volume={27}, DOI={10.1088/0957-0233/27/10/105601},
number={10}, journal={Measurement Science and Technology}, author={Bause, Fabian
and Rautenberg, Jens and Feldmann, Nadine and Webersen, Manuel and Claes, Leander
and Gravenkamp, Hauke and Henning, Bernd}, year={2016} }'
chicago: Bause, Fabian, Jens Rautenberg, Nadine Feldmann, Manuel Webersen, Leander
Claes, Hauke Gravenkamp, and Bernd Henning. “Ultrasonic Transmission Measurements
in the Characterization of Viscoelasticity Utilizing Polymeric Waveguides.” Measurement
Science and Technology 27, no. 10 (2016). https://doi.org/10.1088/0957-0233/27/10/105601.
ieee: F. Bause et al., “Ultrasonic transmission measurements in the characterization
of viscoelasticity utilizing polymeric waveguides,” Measurement Science and
Technology, vol. 27, no. 10, 2016.
mla: Bause, Fabian, et al. “Ultrasonic Transmission Measurements in the Characterization
of Viscoelasticity Utilizing Polymeric Waveguides.” Measurement Science and
Technology, vol. 27, no. 10, 2016, doi:10.1088/0957-0233/27/10/105601.
short: F. Bause, J. Rautenberg, N. Feldmann, M. Webersen, L. Claes, H. Gravenkamp,
B. Henning, Measurement Science and Technology 27 (2016).
date_created: 2019-01-09T14:36:57Z
date_updated: 2022-01-06T07:03:11Z
department:
- _id: '49'
doi: 10.1088/0957-0233/27/10/105601
intvolume: ' 27'
issue: '10'
keyword:
- material characterization
- material parameters
- acoustic waveguide
- daming
- ultrasonic transducer
language:
- iso: eng
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
- _id: '87'
grant_number: '222271124'
name: Bestimmung komplexer akustischer Materialkenngrößen
publication: Measurement Science and Technology
quality_controlled: '1'
status: public
title: Ultrasonic transmission measurements in the characterization of viscoelasticity
utilizing polymeric waveguides
type: journal_article
user_id: '23082'
volume: 27
year: '2016'
...