Umberto Martinez

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We have studied the interaction of ethanol with reduced TiO(2)(110)-(1 × 1) by high-resolution scanning tunneling microscopy (STM) measurements and density functional theory calculations. The STM data revealed direct evidence for the coexistence of molecularly and dissociatively adsorbed ethanol species on surface Ti sites. In addition, we found evidence(More)
We report a theoretical investigation of the adsorption of alkali metal atoms deposited on ultrathin oxide films. The properties of Li, Na, and K atoms adsorbed on SiO(2)/Mo(112) and of K on MgO / Ag(100) and TiO(2)/Pt(111) have been analyzed with particular attention to the induced changes in the work function of the system, Phi. On the nonreducible SiO(2)(More)
The possibility to modify the adsorption properties of a porous silica/Mo(112) film by controlling its work function has been studied by a combined STM and density-functional theory approach. While the original film is inert towards metal adsorption, Au atoms and clusters can be stabilized on the surface after Li doping. The Li atoms penetrate the topmost(More)
Jan Frederik Jerratsch,1 Niklas Nilius,1,* Hans-Joachim Freund,1 Umberto Martinez,2 Livia Giordano,2 and Gianfranco Pacchioni2 1Department of Chemical Physics, Fritz-Haber Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany 2Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 53, 20125 Milano, Italy(More)
The adsorption properties of thin silica films on Mo(112) have been tailored by embedding single Pd atoms into the nanopores of the oxide material. The embedded Pd is able to anchor metal adatoms that would not bind to the inert silica surface otherwise. Several adsorption structures, e.g., Pd-Pd, Ag-Pd, and Au-Pd complexes, have been prepared in this way(More)
The stabilization of single Fe atoms in the nanopores of an ultrathin silica film grown on Mo(112) is demonstrated with scanning tunneling microscopy (STM) and density functional theory (DFT). The Fe atoms are able to penetrate the openings in the oxide surface and adsorb in two different binding configurations at the metal-oxide interface. In the(More)
The adsorption of Pd, Ag and Au atoms on a porous silica film on Mo(112) is investigated by scanning tunneling microscopy and density functional theory. While Pd atoms are able to penetrate the holes in the silica top-layer with virtually no barrier, Ag atoms experience an intermediate barrier value and Au atoms are completely unable to pass the oxide(More)
The water-TiO(2) interaction is of paramount importance for many processes occurring on TiO(2), and the rutile TiO(2)(110)-(1×1) surface has often been considered as a test case. Yet, no consensus has been reached whether the well-studied surface O vacancies on the terraces are the only active sites for water dissociation on rutile TiO(2)(110)-(1 × 1), or(More)
The rutile TiO2(110) surface is the most studied surface of titania and considered as a prototype of transition metal oxide surfaces. Reactions on flat TiO2(110)-(1×1) surfaces are well studied, but the processes occurring on the step edges have barely been considered. Based on scanning tunneling microscopy studies, we here present experimental evidence for(More)