SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 101: Poster Session VIII: Oxides and insulators: Adsorption and reaction of small molecules II
O 101.6: Poster
Donnerstag, 4. März 2021, 13:30–15:30, P
Momentum for Catalysis: How Surface Reactions Shape the RuO2 Flat Surface State — Vedran Jovic1,2, Armando Consiglio3, Kevin E. Smith4, Chris Jozwiak1, Aaron Bostwick1, Eli Rotenberg1, Domenico Di Sante3, and •Simon Moser1,3 — 1Advanced Light Source, USA — 2GNS Science, New Zealand — 3Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Germany — 4Boston University, USA
The active (110) surface of the benchmark oxygen evolution catalyst RuO2 spans a flat-band surface state (FBSS) between the surface projections of its Dirac nodal lines (DNL) that define the electronic properties of this functional semimetal. Monitoring well known surface adsorption processes of H2, O2, NO and CO by in-operando angle resolved photoemission spectroscopy, we selectively modify the oxidation state of individual Ru surface sites and identify the electronic nature of the FBSS: Stabilized by bridging oxygen Obr pz, the FBSS disperses along <001> oriented chains of bridging Rubr 4dz2 orbitals, collapses upon Obr removal, yet, remains surprisingly unaffected by the oxidation state of the undercoordinated 1f-cus-Ru species. This directly reflects in the ability of RuO2 (110) to oxidize CO and H2 along with its inability to oxidize NO, demonstrating the FBSS’s active role in catalytic charge transfer processes at the oxygen bridge sites. Our synergetic approach provides momentum resolved insights to the interplay of a catalyst’s delocalized electronic band structure and the localized orbitals of its surface reactants - a route towards a microscopic understanding of heterogeneous catalysis.