Nanoengineered PtCo and PtNi catalysts for oxygen reduction reaction: An assessment of the structural and electrocatalytic properties

Rameshwori Loukrakpam, Jin Luo, Ting He, Yongsheng Chen, Zhichuan Xu, Peter N. Njoki, Bridgid N. Wanjala, Bin Fang, Derrick Mott, Jun Yin, Jonathan Klar, Brian Powell, Chuan Jian Zhong

Research output: Contribution to journalArticlepeer-review

161 Citations (Scopus)

Abstract

The ability to nanoengineer catalysts in terms of size, composition, shape, and phase properties is essential in exploiting the catalytic properties. This paper reports the results of an investigation of the structural and electrocatalytic properties of PtM (M = Co and Ni) nanoparticles and their carbon-supported electrocatalysts for an oxygen reduction reaction (ORR). Examples are focused on PtCo and PtNi nanoparticles in the range of 2-9 nm and in the composition range of 50-75% Pt. A sharp contrast in size dependence of the activity was revealed between PtCo/C and PtNi/C catalysts, showing a clear trend of decrease in activity with increasing particle size for PtCo/C and a subtle increase in activity for PtNi/C. The size-activity correlation also depends on the bimetallic composition. The detailed analyses of the structures of the catalysts by XAS technique revealed important information for assessing the electrocatalytic properties in relation to the relative amount of oxygenated species and the relative change in interatomic bond distance in the bimetallic nanoparticles, which suggest that a combination of structural parameters such as the change in Pt-Pt bond distance, the segregation of metal phases, and the formation of surface oxygenated species is operative for the size dependence of the enhanced electrocatalytic activity.

Original languageEnglish
Pages (from-to)1682-1694
Number of pages13
JournalJournal of Physical Chemistry C
Volume115
Issue number5
DOIs
Publication statusPublished - 2011 Feb 10
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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