In situ studies on palladium/rutile titanium dioxide exposed to low pressure hydrogen gas environments

Bongers, Marian David

dc.contributor.advisor	Pundt, Astrid Prof. Dr.
dc.contributor.author	Bongers, Marian David
dc.date.accessioned	2018-11-12T09:45:39Z
dc.date.available	2018-11-12T09:45:39Z
dc.date.issued	2018-11-12
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-002E-E4F7-A
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-7122
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	530	de
dc.title	In situ studies on palladium/rutile titanium dioxide exposed to low pressure hydrogen gas environments	de
dc.type	doctoralThesis	de
dc.contributor.referee	Pundt, Astrid Prof. Dr.
dc.date.examination	2018-02-05
dc.subject.gok	Physik (PPN621336750)	de
dc.description.abstracteng	The interaction of hydrogen gas with the palladium/rutile titanium dioxide model system was investigated with strong focus on the interface and its vicinity. Palladium (Pd) films were deposited on pretreated rutile titanium dioxide (r-TiO$_2$) single crystals by using magnetron sputtering. The proposed procedure results in an atomically sharp interface. The orientation relationship between Pd and r-TiO$_2$ was derived by x-ray and high resolution transmission electron microscopy investigations (HRTEM). In situ investigations were carried out on the Pd/r-TiO$_2$ system applying different hydrogen gas partial pressures in an environmental transmission electron microscope (ETEM). Here, especially the energetic structure of the interface and its vicinity was studied utilizing electron energy loss spectroscopy (EELS) on the titanium L$_{3,2}$ edge. Density functional theory (DFT) calculations were carried out, using a hybrid functional, to understand the origin of the observed changes in the EELS measurements. The EELS experiments suggest the accumulation of defects at the interface and its vicinity. A combination of EELS and DFT suggests high defect concentrations at the interface and its vicinity in a hydrogen gas environment. The DFT calculations predict this defect to be the hydrogenated oxygen vacancy. In addition, high resolution scanning TEM (HRSTEM) and positron annihilation spectroscopy (PAS) was applied to reveal changes in the vacancy and the dislocation density in the Pd films as a function of the hydrogen partial pressure uncovering a strong pressure dependency.	de
dc.contributor.coReferee	Seibt, Michael Prof. Dr.
dc.contributor.thirdReferee	Hofsäss, Hans Christian Prof. Dr.
dc.contributor.thirdReferee	Kirchheim, Reiner Prof. Dr.
dc.contributor.thirdReferee	Moshnyaga, Vasily Prof. Dr.
dc.contributor.thirdReferee	Wenderoth, Martin PD Dr.
dc.subject.eng	electron energy loss spectroscopy	de
dc.subject.eng	EELS	de
dc.subject.eng	palladium	de
dc.subject.eng	rutile titanium dioxide	de
dc.subject.eng	interface	de
dc.subject.eng	hydrogen	de
dc.subject.eng	defect	de
dc.subject.eng	in situ	de
dc.subject.eng	environmental transmission electron microscopy	de
dc.subject.eng	ETEM	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E4F7-A-3
dc.affiliation.institute	Fakultät für Physik	de
dc.identifier.ppn	1040426859

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