Promotion Effect of Platinum on Gold's Reactivity: A High-Resolution Photoelectron Spectroscopy Study

Author(s)

Prieto, Mauricio J. ^{[1, 2]} ; Carbonio, Emilia A. ^{[1, 3, 4]} ; Landers, Richard ^[1] ; de Siervo, Abner ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Fis Gleb Wataghin, Dept Fis Aplicada, BR-13083859 Campinas, SP - Brazil

^[2] Fritz Haber Inst Max Planck Gesell, Abt Chem Phys, Faradayweg 4-6, D-14195 Berlin - Germany

^[3] HelmholtzZentrum Berlin Mat & Energie, BESSY II, Albert Einstein Str 15, D-12489 Berlin - Germany

^[4] Fritz Haber Inst Max Planck Gesell, Abt Anorgan Chem, Faradayweg 4-6, D-14195 Berlin - Germany

• Document type: Journal article
• Source: Journal of Physical Chemistry C; v. 120, n. 19, p. 10227-10236, MAY 19 2016.
• Web of Science Citations: 1

Abstract

The reactivity of the Pt/Au(332) surface was studied using high-resolution photoelectron spectroscopy and carbon monoxide adsorption at 3.5 x 10(-3) mbar. The characterization of Pt/Au(332) indicates the formation of a Au-Pt surface alloy at the topmost atomic layer of the (332) crystal due to an atomic exchange mechanism at both terrace and step edge. The amount of alloyed Au atoms has proven to be dependent on the amount of Pt deposited in the coverage range investigated. The activation of Au atoms by alloying is detected by comparing the ability of the surface to adsorb CO at high pressures. By analyzing the C 1s and O 1s photoemission lines it is possible to conclude that CO adsorption is both dissociative and molecular on the PtAu/Au(332) surface, differently from the behavior observed for Au and Pt single crystals. Also, by rising the temperature of the COads-PtAu/Au(332) surface, a dissociative reaction path is followed by the accumulation of graphitic carbon on the surface and the oxygen/carbon dioxide desorption. Thus, our results show not only the differential catalytic behavior of Pt@Au/Au(hkl) model surfaces but also that Au atoms have an active role on the reaction mechanism. (AU)

• FAPESP's process: 07/54829-5 - Electronic and geometric structure of nano-materials: synchrotron radiation studies
• Grantee: Richard Landers
• Support Opportunities: Research Projects - Thematic Grants