Segregation and Selective Oxidation of Ni Atoms in Pt3Ni(111) in a Low-Pressure Oxygen Environment

• Published in: Journal of physical chemistry. C 2013-12, Vol.117 (51), p.27007-27011
• Main Authors: Politano, A, Caputo, M, Goldoni, A, Torelli, P, Chiarello, G
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; Catalysts: preparations and properties; Chemistry; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp409917b

Understanding the microscopic mechanism of oxygen interaction with the surfaces of Pt-based alloys is an important issue for applications in various fields such as corrosion and oxygen reaction reduction in fuel cells, for which Pt-based alloys are more efficient catalysts with respect to platinum. Herein, the interaction of oxygen with Pt3Ni(111) has been studied by X-ray photoemission, X-ray absorption, and high-resolution electron energy loss spectroscopies. We have found that the oxidation of Pt3Ni(111) at 600 K leads to the segregation of Ni atoms to the surface region. The presence of Ni atoms at the Pt3Ni(111) surface allows O2 to dissociate to form NiO x surface species. High-resolution electron energy loss spectroscopy measurements performed on Pt(111), Ni(111), and Pt3Ni(111) directly show that, on the Pt3Ni(111) surface, oxygen binds selectively on Ni sites and, moreover, that the O–Ni bond formed on Pt3Ni is weaker than the O–Pt bond formed on Pt(111).