Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 24: Catalysis: Structural Effects
O 24.1: Vortrag
Dienstag, 17. März 2015, 10:30–10:45, MA 144
Theoretical and in-situ studies for the dissociation of water on an active Ni/CeO2 catalyst: Importance of strong metal-support interactions for the cleavage of O−H bonds — •M. V. Ganduglia-Pirovano1, D. López-Durán1,2, J. Carrasco1,2, Z. Liu3, S. D. Senanayake3, T. Duchoň4, V. Matolín4, and J. A. Rodriguez3 — 1Inst. de Catálisis y Petroleoquímica, CSIC, Spain — 2CIC Energigune, Álava, Spain — 3Brookhaven Natl. Lab., N.Y., U.S. — 4Faculty of Math. and Phys., Charles Univ., Praha, Czech Rep.
Water dissociation is crucial in numerous heterogeneous catalytic reactions on oxide-supported transition-metal catalysts. Here, supported by a combination of density-functional theory and experimental results, we elucidate the effect of the support on O−H bond cleavage activity for nickel/ceria systems. Ambient-pressure O1s photoemission spectra at low Ni loadings on CeO2(111) reveal a substantially larger amount of OH groups as compared to the bare oxide support. Our computed activation energy barriers for water dissociation show an enhanced reactivity of Ni adatoms on CeO2(111) compared with larger Ni particles and extended Ni(111) surfaces. At the origin of this support effect is the ability of ceria to stabilize oxidized Ni2+ reactive species by accommodating electrons in localized f-states. The fast dissociation of water on Ni/CeO2 has a dramatic effect on the activity and stability of this system as a catalyst for the water-gas shift reaction [1,2].
[1] J. Carrasco et al., J. Phys. Chem. C, 117, 8241 (2013).
[2] J. Carrasco et al., Angew. Chem. (2015), DOI: 10.1002/anie.201410697R2.