TY - GEN A1 - Guttmann, Dominic A1 - Riedel, Björn A1 - Sánchez-Barquilla, Raquel A1 - Morales, Carlos A1 - Flege, Jan Ingo T1 - Oxide formation and oxide/metal interaction in CeOx/Ni(111) T2 - Verhandlungen der DPG N2 - Ni/ceria catalysts exhibit a high activity for methane to methanol conversion, making them very promising for applications within a sustainable economy. Possibly, their activity may be strongly enhanced due to the facile exchange between Ce4+ and Ce3+ states, with the latter likely responsible for activating O-H and C-H bonds. Here, we aim to unravel the complex metal-oxide interactions in the inverse CeOx/Ni(111) system under oxidizing and reducing environments. Using low-energy electron diffraction (LEED) we find that the CeOx(111) grown by reactive molecular beam epitaxy preferentially aligns with the main directions of the Ni(111) substrate or is azimuthally rotated by ±10°. By using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS), we find that less NiO is formed during deposition of CeOx than when it is held without ceria at the same conditions (O2 partial pressure and temperature). Finally, we observe a complex behavior of the cerium and nickel oxidation states when exposing the system to O2 or H2 atmospheres. KW - Low-energy electron diffraction (LEED) KW - ceria KW - X-ray photoelectron spectroscopy (XPS) KW - ultraviolet photoelectron spectroscopy (UPS) KW - oxidation states Y1 - 2024 UR - https://www.dpg-verhandlungen.de/year/2024/conference/berlin/part/o/session/33/contribution/10 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Kosto, Yuliia A1 - Kapuscik, Paulina A1 - Tschammer, Rudi A1 - Guttmann, Dominic A1 - Mankowska, Ewa A1 - Matvija, Peter A1 - Morales, Carlos A1 - Mazur, Michał A1 - Henkel, Karsten A1 - Matolinova, Iva A1 - Domaradzki, Jarosław A1 - Flege, Jan Ingo T1 - Bare and Pd-doped ceria thin films prepared by ALD and EBE for hydrogen detection T2 - Verhandlungen der DPG N2 - The need to store and use hydrogen safely as part of green economy based on renewable energy evokes a necessity to reliably detect it at ambient conditions. The majority of currently used sensors are working at elevated temperatures (200-500 °C). In this work, we demonstrate that ceria films deposited on a commercial electrode by atomic layer deposition (ALD) and electron beam evaporation (EBE) electrically respond to hydrogen (from 20 to 500 ppm) at much lower temperatures (50-200 °C). The results reveal that <1.5 nm thin Pd adlayer increases the electrical response by several orders of magnitude for both ceria films. The NAP-XPS study under changing oxidative/reductive atmospheres sheds light on the mechanism of Pd-CeOx thermal activation and the role of the deposition technique in the reactivity of the oxide. KW - Hydrogen sensor KW - Atomic layer deposition (ALD) KW - ceria KW - Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) Y1 - 2024 UR - https://www.dpg-verhandlungen.de/year/2024/conference/berlin/part/o/session/59/contribution/5 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER -