title: Carbon dioxide hydrogenation on Ni(110).
abstract: We demonstrate that the key step for the reaction of CO 2 with hydrogen on Ni(110) is a change of the activated molecule coordination to the metal surface. At 90 K, CO 2 is negatively charged and chemically bonded via the carbon atom. When the temperature is increased and H approaches, the H-CO 2 complex flips and binds to the surface through the two oxygen atoms, while H binds to the carbon atom, thus yielding formate. We provide the atomic-level description of this process by means of conventional ultrahigh vacuum surface science techniques combined with density functional theory calculations and corroborated by high pressure reactivity tests. Knowledge about the details of the mechanisms involved in this reaction can yield a deeper comprehension of heterogeneous catalytic organic synthesis processes involving carbon dioxide as a reactant. We show why on Ni the CO 2 hydrogenation barrier is remarkably smaller than that on the common Cu metal-based catalyst. Our results provide a possible interpretation of the observed high catalytic activity of NiCu alloys.
authors.affiliation: Physics Department and Center of Excellence for Nanostructured Materials (CENMAT), University of Trieste, Via A. Valerio 2, I-34127, Trieste, Italy. vesselli@tasc.infm.it
authors.forename: Erik
authors.initials: E
authors.lastname: Vesselli
authors.forename: Loredana
authors.initials: L
authors.lastname: De Rogatis
authors.forename: Xunlei
authors.initials: X
authors.lastname: Ding
authors.forename: Alessandro
authors.initials: A
authors.lastname: Baraldi
authors.forename: Letizia
authors.initials: L
authors.lastname: Savio
authors.forename: Luca
authors.initials: L
authors.lastname: Vattuone
authors.forename: Mario
authors.initials: M
authors.lastname: Rocca
authors.forename: Paolo
authors.initials: P
authors.lastname: Fornasiero
authors.forename: Maria
authors.initials: M
authors.lastname: Peressi
authors.forename: Alfonso
authors.initials: A
authors.lastname: Baldereschi
authors.forename: Renzo
authors.initials: R
authors.lastname: Rosei
authors.forename: Giovanni
authors.initials: G
authors.lastname: Comelli