Maria Veronica Ganduglia-Pirovano1
Institute of Catalysis and Petrochemistry-CSIC1
Ceria (CeO<sub>2</sub>) -an easily reducible oxide- is the most significant of the oxides of rare-earth metals in industrial catalysis. Deep understanding of oxygen vacancy defects at ceria surfaces, is central to our understanding of the role of ceria in catalysis. For the CeO<sub>2</sub>(111) surface, whether oxygen vacancies prefer the subsurface or the surface, and if surface oxygen vacancies attract or repel, as well as whether oxygen vacancy migration and polaron (Ce<sup>3+</sup>) hopping are entangled, are still heavily debated. Also, a number of ordered phases have been observed upon reduction but their structures have remained elusive. Here, supported by experimental and theoretical results, obtained employing density functional theory in combination with statistical thermodynamics, Monte Carlo simulations, and ab-initio molecular dynamics, the current understanding of the structure of the CeO<sub>2-x </sub>(111) surface will be discussed [1-9]. Moreover, the function of ceria as support in the catalytic activity of metal-ceria systems for a reaction that is attracting a lot of interest due to its green nature, namely methane dry reforming (MDR) which coverts CO<sub>2</sub> and CH<sub>4</sub> to produce syngas (CO/H<sub>2</sub>), is not fully understood. In this talk, recent results on Metal (Ni, Co, Pt) /CeO<sub>2</sub>(111) model catalysts will be presented [10-14]. The emphasis is here put on theoretical studies in combination with experiments using in situ/operando methods (AP-XPS, XRD, and XAFS) and catalytic testing, and special attention is given to the effects of the metal loading, the metal-ceria interactions and the presence of oxygen vacancies as key factors determining the catalytic activity.<br/>1. Ganduglia-Pirovano, M. V.; Da Silva, J. L. F.; Sauer, J. <i>Phys. Rev. Lett. </i><b>2009</b>, <i>102, </i>026101.<br/>2. Jerratsch, J. F.; Shao, X.; Nilius, N.; Freund, H. J.; Popa, C.; Ganduglia-Pirovano, M. V.; Burow, A. M.; Sauer, J. <i>Phys. Rev. Lett. </i><b>2011</b>, <i>106, </i>246801.<br/>3. Murgida G. E.; Ganduglia-Pirovano, M. V. <i>Phys. Rev. Lett. </i><b>2013</b>, <i>110, </i>246101.<br/>4. Murgida, G. E.; Ferrari, V.; Llois, A. M.; Ganduglia-Pirovano, M. V. <i>Phys. Rev. B</i> <b>2014</b>, <i>90</i>, 115120.<br/>5. Olbrich, R.; Murgida, G. E.; Ferrari, V.; Barth, C.; Llois, A. M.; Reichling, M.; Ganduglia-Pirovano, M. V. <i>J. Phys. Chem. C </i><b>2017</b>, <i>121, </i>6844.<br/>6. Murgida, G. E.; Ferrari, V.; Llois, A. M.; Ganduglia-Pirovano, M. V. <i>Phys. Rev. Materials</i> <b>2018</b>, <i>2</i>, 083609.<br/>7. Han, Z.-K.; Yang, Y.-Z.; Zhu, B.; Ganduglia-Pirovano, M. V.; Gao, Y. <i>Phys. Rev. Materials</i> <b>2018</b>, <i>2</i>, 035802.<br/>8. Zhang, D.; Han, Z.-K.; Murgida, G. E.; Ganduglia-Pirovano, M. V.; Gao, Y. <i>Phys. Rev. Lett.</i> <b>2019</b>, <i>122</i>, 019601.<br/>9. Pérez-Bailac, P.; Lustemberg, P. G.; Ganduglia-Pirovano, M. V. <i>J. Phys.: Condens. Matter</i> <b>2021</b>, <i>33</i>, 504003.<br/>10. Lustemberg, P. G.; Ramírez, P. J.; Liu, Z.; Gutiérrez, R. A.; Grinter, D. C.; Carrasco,J.; Senanayake, S. D.; Rodriguez, J. A.; Ganduglia-Pirovano, M. V<i>. ACS Catal.</i> <b>2016</b>, <i>6</i>, 8184.<br/>11. Liu, Z.; Lustemberg, P. G.; Gutiérrez, R. A.; Carey, J. J.; Palomino, R. M.; Vorokhta, M.; Grinter, D. C.; Ramírez, P. J.; Matolín, V.; 12. Nolan, M.; Ganduglia-Pirovano, M. V.; Senanayake, S. D.; Rodriguez, J. A. <i>Angew. Chem. Int. Ed.</i> <b>2017</b>, <i>56</i>, 13041.<br/>12. Liu, Z.; Grinter, D. C.; Lustemberg, P. G.; Nguyen-Phan, T.; Zhou, Y.; Luo, S.; Waluyo, I.; Crumlin, E. J.; Stacchiola, D. J.; Zhou, J.; Grinter, D. C.; Busnengo, H. F.; Ganduglia-Pirovano, M. V.; Senanayake, S. D.; Rodriguez, J. A. <i>Angew. Chem., Int. Ed.</i> <b>2016</b>, <i>55</i>, 7455.<br/>13. Lustemberg, P. G.; Zhang, F.; Gutiérrez, R. A.; Ramírez, P. J.; Senanayake, S. D.; Rodriguez, J. A.; Ganduglia-Pirovano, M. V. <i>J. Phys. Chem. Lett.</i> <b>2020</b>, <i>11</i>, 9131.<br/>14. Zhang, F.; Gutiérrez, R. A.; Lustemberg, P. G.; Liu, Z.; Rui N.; Wu T.; Ramírez, P. J.; Xu W.; Idriss H.; Ganduglia-Pirovano, M. V.; Senanayake, S. D.; Rodriguez, J. A. <i>ACS Catal.</i> <b>2021</b>, <i>11</i>, 1613.