TY - GEN A1 - Pleines, Linus A1 - Genuzio, Francesca A1 - Menteş, Tevfik Onur A1 - Locatelli, Andrea A1 - Falta, Jens A1 - Flege, Jan Ingo T1 - Reduction and reoxidation of (111) and (100) oriented cerium oxide islands on Cu(111) T2 - Verhandlungen der DPG N2 - The conversion of CO2 to methanol is an important process of high industrial potential. It could help solving the greenhouse gas problem (CO2) and further provide methanol which can be used as a synthetic fuel. In order to lower the activation energy barrier of the reactions a catalyst is necessary. We studied the interaction of H2 and CO2 with ultrathin cerium oxide islands on a Cu(111) substrate observed by low-energy electron mircoscopy (LEEM), x-ray absorption spectroscopy (XAS) and resonant photoelectron spectroscopy (RPES). From earlier studies the orientation of the CeOx is known to be decisive for the catalytic activity. In our experiments CeOx(100) is directly compared to CeOx(111) via a side-by-side growth, so that the same conditions prevail during the experiment. At low temperatures no reduction of the CeOx(111) and CeOx(100) were observed. However, at a higher temperature the reduction was activated. Furthermore, we show that the exposure to CO2 leads to the formation of partially reoxidized CeOx and saturation below CeO2 with progressive CO2 exposure. KW - conversion of CO2 to methanol KW - low-energy electron mircoscopy (LEEM) KW - x-ray absorption spectroscopy (XAS) KW - resonant photoelectron spectroscopy (resPES) Y1 - 2019 UR - https://www.dpg-verhandlungen.de/year/2019/conference/regensburg/part/o/session/37/contribution/10 SN - 0420-0195 SP - 330 EP - 330 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Pleines, Linus A1 - Buß, Lars A1 - Menteş, Tevfik Onur A1 - Genuzio, Francesca A1 - Locatelli, Andrea A1 - Falta, Jens A1 - Flege, Jan Ingo T1 - In-situ characterization of cyclic reduction and reoxidation of CeOx(111) and CeOx(100) islands on Cu(111) T2 - Verhandlungen der DPG N2 - Cerium oxide (CeOx) is of special interest due to its catalytic activity and various other electronic and optical applications. The inverse model catalyst CeOx on Cu(111) has a high activity for methanol synthesis from H2 and CO2. For the activation of CO2, Ce3+ sites have to be present at the surface, which means that the CeOx has to be reduced to some extent. This may be achieved by exposure to H2 at elevated temperatures. We studied the interaction of H2 and CO2 with CeOx islands on Cu(111) with low-energy electron microscopy (LEEM) and X-ray absorption spectroscopy (XAS). From earlier studies, the orientation of the CeOx is known to be decisive for its catalytic activity. In our experiments (100) and (111) CeOx islands are grown side by side on the metal substrate, so that identical reaction conditions prevail during the experiment. At a high temperature of 550 ∘C, exposure to H2 leads to partial reduction, and exposure to CO2 leads to reoxidation of the CeOx. The differences observed for the two island orientations regarding structure and composition will be discussed. KW - methanol synthesis KW - low-energy electron microscopy (LEEM) KW - X-ray absorption spectroscopy (XAS) KW - partial reduction KW - reoxidation Y1 - 2022 UR - https://www.dpg-verhandlungen.de/year/2022/conference/regensburg/part/o/session/69/contribution/10 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER -