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  1. Artikel ; Online: Tuning the morphology and chemical distribution of Ag atoms in Au rich nanoparticles using electrochemical dealloying.

    Dworzak, Alexandra / Paciok, Paul / Mahr, Christoph / Heggen, Marc / Dosche, Carsten / Rosenauer, Andreas / Oezaslan, Mehtap

    Nanoscale

    2024  Band 16, Heft 19, Seite(n) 9603–9616

    Abstract: Dealloying of Ag-Au alloy nanoparticles (NPs) strongly differs from the corresponding bulk alloy materials. Here, we have investigated the effects of potentiodynamic and potentiostatic dealloying on structure and distribution of residual Ag atoms for Au ... ...

    Abstract Dealloying of Ag-Au alloy nanoparticles (NPs) strongly differs from the corresponding bulk alloy materials. Here, we have investigated the effects of potentiodynamic and potentiostatic dealloying on structure and distribution of residual Ag atoms for Au rich NPs. Two different sizes of Ag rich alloy NPs, 77 ± 26 nm Ag
    Sprache Englisch
    Erscheinungsdatum 2024-05-16
    Erscheinungsland England
    Dokumenttyp Journal Article
    ZDB-ID 2515664-0
    ISSN 2040-3372 ; 2040-3364
    ISSN (online) 2040-3372
    ISSN 2040-3364
    DOI 10.1039/d4nr00046c
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  2. Artikel: Ordered Porous Electrodes Obtained Using LIFT for Electrochemical Applications.

    Rager, Korbinian / Tang, Bo / Schneemann, Christian / Dworzak, Alexandra / Oezaslan, Mehtap / Dietzel, Andreas

    Materials (Basel, Switzerland)

    2023  Band 16, Heft 2

    Abstract: Numerous synthetic techniques for the fabrication of porous metal electrodes were developed in recent decades. A very promising and facile route is the 3D printing of structures, which can be designed directly on the computer first. However, the current ... ...

    Abstract Numerous synthetic techniques for the fabrication of porous metal electrodes were developed in recent decades. A very promising and facile route is the 3D printing of structures, which can be designed directly on the computer first. However, the current techniques allow structures to be printed with a resolution down to 20 µm, which is still quite rough regarding tuning the pore distribution and diameter of electrode materials for potential applications. For the first time, a laser-induced forward transfer (LIFT) process was used to 3D print metal voxels on a solid surface, resulting in a porous electrocatalytically active gold (Au) electrode film. Porous Au electrodes produced using LIFT showed an increase in the electrochemically active surface area (SA) by a factor of four compared with a sputtered dense Au film when characterized using cyclic voltammetry (CV) in Ar-saturated 0.1 M KOH. Therefore, the LIFT process can be considered very promising for the printing of ordered porous electrodes with high surface areas for electrochemical applications.
    Sprache Englisch
    Erscheinungsdatum 2023-01-07
    Erscheinungsland Switzerland
    Dokumenttyp Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma16020596
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  3. Artikel ; Online: Quantitative 3D Characterization of Nanoporous Gold Nanoparticles by Transmission Electron Microscopy.

    Mahr, Christoph / Dworzak, Alexandra / Schowalter, Marco / Oezaslan, Mehtap / Rosenauer, Andreas

    Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada

    2021  Band 27, Heft 4, Seite(n) 678–686

    Abstract: Quantitative structural characterization of nanomaterials is important to tailor their functional properties. Corrosion of AgAu-alloy nanoparticles (NPs) results in porous structures, making them interesting for applications especially in the fields of ... ...

    Abstract Quantitative structural characterization of nanomaterials is important to tailor their functional properties. Corrosion of AgAu-alloy nanoparticles (NPs) results in porous structures, making them interesting for applications especially in the fields of catalysis and surface-enhanced Raman spectroscopy. For the present report, structures of dealloyed NPs were reconstructed three-dimensionally using scanning transmission electron microscopy tomography. These reconstructions were evaluated quantitatively, revealing structural information such as pore size, porosity, specific surface area, and tortuosity. Results show significant differences compared to the structure of dealloyed bulk samples and can be used as input for simulations of diffusion or mass transport processes, for example, in catalytic applications.
    Sprache Englisch
    Erscheinungsdatum 2021-06-04
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 1385710-1
    ISSN 1435-8115 ; 1431-9276
    ISSN (online) 1435-8115
    ISSN 1431-9276
    DOI 10.1017/S1431927621000519
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  4. Artikel: Nanoporous Copper Ribbons Prepared by Chemical Dealloying of a Melt-Spun ZnCu Alloy

    Ibrahim, Sawsan / Dworzak, Alexandra / Crespo, Daniel / Renner, Frank Uwe / Dosche, Carsten / Oezaslan, Mehtap

    Journal of physical chemistry. 2021 Dec. 29, v. 126, no. 1

    2021  

    Abstract: Dealloying is a powerful and versatile method to fabricate three-dimensional nanoporous (np) materials with high surface area. In this work, we investigated the dealloying processes of Zn₈₀Cu₂₀ alloy ribbons in acidic and alkaline environments. Our ... ...

    Abstract Dealloying is a powerful and versatile method to fabricate three-dimensional nanoporous (np) materials with high surface area. In this work, we investigated the dealloying processes of Zn₈₀Cu₂₀ alloy ribbons in acidic and alkaline environments. Our results show that the nanostructure can be controlled by varying the nature of electrolyte solution, pH value, dealloying time, and temperature. In acidic media, the presence of chloride ions enhances the Cu surface mobility, leading to a faster coarsening and growth of ligaments during the dealloying process over time. In contrast, the surface diffusivity of Cu atoms in alkaline media is three orders lower than that in acid and results in a remarkably smaller ligament size due to the formation of Cu (hydr)oxide surface species. Cross-section analysis indicates that the dealloying process is largely controlled by interfacial processes. Interestingly, local Zn-rich regions were found near the surface in np-Cu ribbons dealloyed in 0.1 M HCl. This comprehensive study shows the influence of dealloying conditions on the morphology and residual Zn content of np-Cu ribbons as a model system for fabricating bicontinuous ligament-pore network materials with tailored structural and chemical properties for applications in electrochemical synthesis, sensors, and catalysis.
    Schlagwörter alloys ; catalytic activity ; chlorides ; diffusivity ; electrosynthesis ; ligaments ; nanopores ; pH ; physical chemistry ; surface area ; temperature
    Sprache Englisch
    Erscheinungsverlauf 2021-1229
    Umfang p. 212-226.
    Erscheinungsort American Chemical Society
    Dokumenttyp Artikel
    ISSN 1932-7455
    DOI 10.1021/acs.jpcc.1c08258
    Datenquelle NAL Katalog (AGRICOLA)

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  5. Artikel ; Online: Chemical Insights into the Formation of Colloidal Iridium Nanoparticles from In Situ X-ray Total Scattering: Influence of Precursors and Cations on the Reaction Pathway.

    Mathiesen, Jette K / Quinson, Jonathan / Blaseio, Sonja / Kjær, Emil T S / Dworzak, Alexandra / Cooper, Susan R / Pedersen, Jack K / Wang, Baiyu / Bizzotto, Francesco / Schröder, Johanna / Kinnibrugh, Tiffany L / Simonsen, Søren B / Theil Kuhn, Luise / Kirkensgaard, Jacob J K / Rossmeisl, Jan / Oezaslan, Mehtap / Arenz, Matthias / Jensen, Kirsten M Ø

    Journal of the American Chemical Society

    2023  Band 145, Heft 3, Seite(n) 1769–1782

    Abstract: Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles have also been a key for the development of kinetic models of nanomaterial formation. However, compared to other metals ... ...

    Abstract Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles have also been a key for the development of kinetic models of nanomaterial formation. However, compared to other metals such as gold or platinum, knowledge on the nature of prenucleation species and structural insights into the resultant nanoparticles are missing, especially for nanoparticles obtained from Ir
    Sprache Englisch
    Erscheinungsdatum 2023-01-11
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.2c10814
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  6. Artikel ; Online: Insights from

    Mathiesen, Jette K / Quinson, Jonathan / Dworzak, Alexandra / Vosch, Tom / Juelsholt, Mikkel / Kjær, Emil T S / Schröder, Johanna / Kirkensgaard, Jacob J K / Oezaslan, Mehtap / Arenz, Matthias / Jensen, Kirsten M Ø

    The journal of physical chemistry letters

    2021  Band 12, Heft 12, Seite(n) 3224–3231

    Abstract: Understanding the formation of nanomaterials down to the atomic level is key to rational design of advanced materials. Despite their widespread use and intensive study over the years, the detailed formation mechanism of platinum (Pt) nanoparticles ... ...

    Abstract Understanding the formation of nanomaterials down to the atomic level is key to rational design of advanced materials. Despite their widespread use and intensive study over the years, the detailed formation mechanism of platinum (Pt) nanoparticles remains challenging to explore and rationalize. Here, various
    Sprache Englisch
    Erscheinungsdatum 2021-03-25
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.1c00241
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  7. Artikel: Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction.

    Sievers, Gustav W / Jensen, Anders W / Quinson, Jonathan / Zana, Alessandro / Bizzotto, Francesco / Oezaslan, Mehtap / Dworzak, Alexandra / Kirkensgaard, Jacob J K / Smitshuysen, Thomas E L / Kadkhodazadeh, Shima / Juelsholt, Mikkel / Jensen, Kirsten M Ø / Anklam, Kirsten / Wan, Hao / Schäfer, Jan / Čépe, Klára / Escudero-Escribano, María / Rossmeisl, Jan / Quade, Antje /
    Brüser, Volker / Arenz, Matthias

    Nature materials

    2020  Band 20, Heft 2, Seite(n) 208–213

    Abstract: Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt ... ...

    Abstract Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.
    Schlagwörter covid19
    Sprache Englisch
    Erscheinungsdatum 2020-08-24
    Erscheinungsland England
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2088679-2
    ISSN 1476-4660 ; 1476-1122
    ISSN (online) 1476-4660
    ISSN 1476-1122
    DOI 10.1038/s41563-020-0775-8
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  8. Artikel: Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction

    Sievers, Gustav W / Jensen, Anders W / Quinson, Jonathan / Zana, Alessandro / Bizzotto, Francesco / Oezaslan, Mehtap / Dworzak, Alexandra / Kirkensgaard, Jacob J K / Smitshuysen, Thomas E L / Kadkhodazadeh, Shima / Juelsholt, Mikkel / Jensen, Kirsten M Ø / Anklam, Kirsten / Wan, Hao / Schäfer, Jan / Cépe, Klára / Escudero-Escribano, María / Rossmeisl, Jan / Quade, Antje /
    Brüser, Volker / Arenz, Matthias

    Nat. materials

    Abstract: Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt ... ...

    Abstract Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.
    Schlagwörter covid19
    Verlag WHO
    Dokumenttyp Artikel
    Anmerkung WHO #Covidence: #32839587
    Datenquelle COVID19

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