"Preparation and characterization of PdFe nanoleaves as electrocatalyst" by Zhiyong Zhang, Karren L. More et al.
 

Preparation and characterization of PdFe nanoleaves as electrocatalysts for oxygen reduction reaction

Document Type

Article

Publication Date

3-22-2011

Abstract

Novel PdFe-nanoleaves (NLs) have been prepared through a wet chemistry-based solution phase reduction synthesis route. High-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (S/TEM) coupled with high-spatial-resolution compositional analysis clearly show that this newly developed structure is assembled from Pd-rich nanowires (Pd-NWs) surrounded by Fe-rich sheets. The Pd-NWs have diameters in the range of 1.8-2.3 nm and large electrochemical surface areas of > 50 m 2/g. Their length (30-100 nm) and morphology can be tuned by altering the nanostructure synthesis conditions and the Fe amount in the NLs. With increasing Fe content, thinner and longer sheet-enveloped nanowires can be prepared. The side surfaces of Pd-NWs observed by HR-TEM are predominantly Pd(111) facets, while the tips and ends are Pd(110) and Pd(100) facets. By etching away the enveloping Fe-rich sheets using an organic acid, the Pd-rich NWs are exposed on the surfaces of the nanoleaves, and they demonstrate high reactivity toward electrocatalytic reduction of oxygen in a 0.1 M NaOH electrolyte, i.e., a factor of 3.0 increase in the specific activity and a factor of 2.7 increase in the mass activity, compared to a commercial Pt/C catalyst (at 0 V vs. Hg/HgO). The electrocatalytic activity enhancement can be attributed to the unique nanoleave structure, which provides more Pd(111) facets, a large surface area, and more resistance to Pd oxide formation. © 2011 American Chemical Society.

Publication Title

Chemistry of Materials

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