Mierwaldt, Daniel

[["dc.bibliographiccitation.firstpage","129"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Catalysts"],["dc.bibliographiccitation.lastpage","145"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Mierwaldt, Daniel"],["dc.contributor.author","Mildner, Stephanie"],["dc.contributor.author","Arrigo, Rosa"],["dc.contributor.author","Knop-Gericke, Axel"],["dc.contributor.author","Franke, Emanuel"],["dc.contributor.author","Blumenstein, Andreas"],["dc.contributor.author","Hoffmann, Joerg"],["dc.contributor.author","Jooß, Christian"],["dc.date.accessioned","2018-11-07T09:39:09Z"],["dc.date.available","2018-11-07T09:39:09Z"],["dc.date.issued","2014"],["dc.description.abstract","Studying catalysts in situ is of high interest for understanding their surface structure and electronic states in operation. Herein, we present a study of epitaxial manganite perovskite thin films (Pr1-xCaxMnO3) active for the oxygen evolution reaction (OER) from electro-catalytic water splitting. X-ray absorption near-edge spectroscopy (XANES) at the Mn L- and O K-edges, as well as X-ray photoemission spectroscopy (XPS) of the O 1s and Ca 2p states have been performed in ultra-high vacuum and in water vapor under positive applied bias at room temperature. It is shown that under the oxidizing conditions of the OER a reduced Mn2+ species is generated at the catalyst surface. The Mn valence shift is accompanied by the formation of surface oxygen vacancies. Annealing of the catalysts in O-2 atmosphere at 120 degrees C restores the virgin surfaces."],["dc.description.sponsorship","DFG CRC 1073 project C02"],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft through the CRC 1073 [C02]"],["dc.identifier.doi","10.3390/catal4020129"],["dc.identifier.isi","000339590600004"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10510"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33215"],["dc.notes","Financial support by the Deutsche Forschungsgemeinschaft through the CRC 1073 project C02"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area C | C02 In situ hochauflösende Untersuchung des aktiven Zustands bei der photo- und elektrochemischen Wasserspaltung"],["dc.relation.issn","2073-4344"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5301"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry C"],["dc.bibliographiccitation.lastpage","5310"],["dc.bibliographiccitation.volume","119"],["dc.contributor.author","Mildner, Stephanie"],["dc.contributor.author","Beleggia, Marco"],["dc.contributor.author","Mierwaldt, Daniel"],["dc.contributor.author","Hansen, Thomas W."],["dc.contributor.author","Wagner, Jakob B."],["dc.contributor.author","Yazdi, Sadegh"],["dc.contributor.author","Kasama, Takeshi"],["dc.contributor.author","Ciston, Jim"],["dc.contributor.author","Zhu, Y."],["dc.contributor.author","Jooß, Christian"],["dc.date.accessioned","2018-11-07T09:59:43Z"],["dc.date.available","2018-11-07T09:59:43Z"],["dc.date.issued","2015"],["dc.description.abstract","Environmental transmission electron microscopy (ETEVI) studies offer great potential for gathering atomic scale information on the electronic state of electrodes in contact with reactants. It also poses big challenges due to the impact of the high energy electron beam. In this article, we present an ETEM study of a Pr0.64Ca0.36MnO3 (PCMO) thin filth electrocatalySt for water splitting and Oxygen evolution in contact with water vapor: We show by means of off-axis electron holography and electrostatic modeling that the electron beam gives rise to a positive electric sample potential due to secondary electron emission. The value of the electric potential depends on the primary electron flux, the sample's electric Conductivity and grounding, and gas properties. We present evidence that two observed electrochemical reactions are driven by a beam induced electrostatic potential of the order of a volt. The first reaction is an anodic oxidation of oxygen depleted amorphous PCMO which results in recrystallization of the oxide. The Second reaction is oxygen evolution which can be detected by the oxidation of a silane additive and formation of SiO2-gamma at catalytically active surfaces. The quantification of beam induced potentials is an important step for future controlled electrochemical experiments in an ETEM."],["dc.description.sponsorship","DFG [SFB 1073]"],["dc.identifier.doi","10.1021/jp511628c"],["dc.identifier.isi","000351189100006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37654"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area C | C02 In situ hochauflösende Untersuchung des aktiven Zustands bei der photo- und elektrochemischen Wasserspaltung"],["dc.relation.issn","1932-7447"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Environmental TEM Study of Electron Beam Induced Electrochemistry of Pr0.64Ca0.36MnO3 Catalysts for Oxygen Evolution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","235150"],["dc.bibliographiccitation.issue","23"],["dc.bibliographiccitation.journal","Physical Review B"],["dc.bibliographiccitation.volume","95"],["dc.contributor.author","Sotoudeh, Mohsen"],["dc.contributor.author","Rajpurohit, Sangeeta"],["dc.contributor.author","Blöchl, Peter"],["dc.contributor.author","Mierwaldt, Daniel"],["dc.contributor.author","Norpoth, Jonas"],["dc.contributor.author","Roddatis, Vladimir"],["dc.contributor.author","Mildner, Stephanie"],["dc.contributor.author","Kressdorf, Birte"],["dc.contributor.author","Ifland, Benedikt"],["dc.contributor.author","Jooss, Christian"],["dc.date.accessioned","2020-12-10T18:25:03Z"],["dc.date.available","2020-12-10T18:25:03Z"],["dc.date.issued","2017"],["dc.description.abstract","The electronic structure of Pr1-xCaxMnO3 has been investigated using a combination of first-principles calculations, x-ray photoelectron spectroscopy (XPS), x-ray absorption spectroscopy (XAS), electron-energy loss spectroscopy (EELS), and optical absorption. The full range of compositions, x = 0,1/2,1, and a variety of magnetic orders have been covered. Jahn-Teller as well as Zener polaron orders are considered. The free parameters of the local hybrid density functionals used in this study have been determined by comparison with measured XPS spectra. A model Hamiltonian, valid for the entire doping range, has been extracted. A simple local-orbital picture of the electronic structure for the interpretation of experimental spectra is provided. The comparison of theoretical calculations and different experimental spectra provide a detailed and consistent picture of the electronic structure. The large variations of measured optical absorption spectra are traced back to the coexistence of magnetic orders (respectively, to the occupation of local orbitals). A consistent treatment of the Coulomb interaction indicates a partial cancellation of Coulomb parameters and supports the dominance of the electron-phonon coupling."],["dc.identifier.doi","10.1103/PhysRevB.95.235150"],["dc.identifier.eissn","2469-9969"],["dc.identifier.isi","000404468000001"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75564"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B02 Photonen-getriebener Energietransfer über Grenzflächen zwischen Materialien mit starken Korrelationen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.relation","SFB 1073 | Topical Area C | C02 In situ hochauflösende Untersuchung des aktiven Zustands bei der photo- und elektrochemischen Wasserspaltung"],["dc.relation","SFB 1073 | Topical Area C | C03 Vom Elektronentransfer zur chemischen Energiespeicherung: ab-initio Untersuchungen korrelierter Prozesse"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Electronic structure of Pr1-xCaxMnO3"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]