Nanoengineered PtCo and PtNi Catalysts for Oxygen Reduction Reaction: An Assessment of the Structural and Electrocatalytic Properties

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• 作者：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
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 10, 2011
• 年：2011
• 卷：115
• 期：5
• 页码：1682-1694
• 全文大小：1213K
• 年卷期：v.115,no.5(February 10, 2011)
• ISSN：1932-7455

文摘

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鈭? nm and in the composition range of 50鈭?5% 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鈭抋ctivity 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鈭扨t 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.