The enhanced activity of mass-selected Pt x Gd nanoparticles for oxygen electroreduction

• Published in: Journal of catalysis Vol. 328; p. 297
• Main Authors: Velázquez-Palenzuela, Amado, Masini, Federico, Pedersen, Anders F, Escudero-Escribano, María, Deiana, Davide, Malacrida, Paolo, Hansen, Thomas W, Friebel, Daniel, Nilsson, Anders, Stephens, Ifan E.L, Chorkendorff, Ib
• Format: Journal Article
• Language: English
• Published: San Diego Elsevier BV 01.08.2015
• Subjects: Catalysts; Chemical reactions; Gold; Nanoparticles; Platinum
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2014.12.012

Display Omitted * Pt x Gd nanoparticles are prepared using sputtering/gas aggregation deposition in UHV. * The Pt x Gd 8-nm catalyst shows the highest mass activity, being 3.6A(mgPt)-1 . * The stability of Pt x Gd 8nm is comparable to that of our previous Pt x Y catalysts. * The ORR enhancement is attributed to strain effects in a core/shell structure. * The compressive strain is used as valid descriptor of the ORR kinetics. Mass-selected platinum-gadolinium alloy nanoparticles (Pt x Gd NPs) are synthesized for the first time as oxygen reduction reaction (ORR) electrocatalysts using the gas aggregation technique, under ultrahigh vacuum (UHV) conditions. The morphology of the Pt x Gd catalysts is characterized, and their catalytic performance toward the ORR is assessed in acidic media using a half-cell configuration. The Pt x Gd 8-nm catalyst shows a high activity (3.6A(mgPt)-1 ), surpassing the highest activity reached so far with Pt x Y NP catalysts. In addition, the optimum Pt x Gd catalyst also presents high stability, as suggested by the accelerated stability tests under ORR potential cycling. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements confirm that as-prepared Pt x Gd NPs are compressively strained, relative to pure Pt, and that a Pt x Gd core/Pt-rich shell structure is adopted after partial Gd leaching. The activity correlates strongly with the compressive strain. On that basis, we propose that the ORR enhancement is due to the compressive strain within the Pt shell induced by the alloy core. The results herein confirm the suitability of Pt x Gd NPs as cathode nanocatalysts for proton exchange membrane fuel cells (PEMFCs).