Student: Dinhová Thu Ngan
Supervisor: Mykhailo Vorokhta, Ph.D.
Status: Assigned
Abstract:
Heterogeneous catalysts undergo structural and chemical changes while in working conditions. To catch those changes, sample analysis before and after a chemical reaction is usually performed. However, very often, the important structural and chemical properties of catalysts responsible for their high efficiency are present only at operational conditions. Accordingly, the utilization of in-situ/operando techniques that give us valuable information about the catalyst layer under operational conditions is of great importance. Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) is a powerful technique that makes possible chemical investigation of different catalyst layers in the presence of gases and vapors, providing information on catalyst oxidation state and reaction intermediate species that appear on the surface.
The dissertation will focus on operando investigation of different catalyst layers relevant for proton exchange membrane fuel cells (PEMFC) and catalytic-type gas sensors. Ceria-based catalysts doped with noble metals will be studied by NAP-XPS as promising highly active anode catalysts of PEMFC. Different platinum-based bimetallic catalysts will be considered and investigated for the cathode side. A substantial part of the work will be dedicated to the determination of catalytic processes responsible for the response of oxide-based gas sensing layers during the detection of different volatile organic compounds. Together with the NAP-XPS technique, other powerful structure and surface characterization techniques such as transmission electron microscopy (TEM) and synchrotron radiation photoelectron spectroscopy (SRPES) are planned to be used in this work.