1D Pd-Based Nanomaterials as Efficient Electrocatalysts for Fuel Cells - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 339

Fig. 20 a-b High-resolution TEM micrographs (HRTEM) of PdAg nanowires at different
magnifications. The scale bars are a 20 nm and b 5 nm. c The high angle annular dark field
(HAADF) STEM image of PdAg nanowires and the corresponding elemental mapping of Ag (d),
Pd (e). f Overlay map of the elements in the PdAg nanowires. Reprinted from Ref. [ 70 ] with
permission by the American Chemical Society
long-term electrochemical stability. On the other hand, the electrochemical
impedance spectroscopy measurements showed that with the electrode potential
increasing the impedance spectra of PdAg nanowires show arcs in the first
quadrant firstly and then negative impedance was observed in the second quadrant
(Fig. 21 a). However, all the impedance spectra of Pd/C are located in the first
quadrant within the entire potential range (Fig. 21 b). The different impedance
results obtained from the two catalysts suggest that PdAg nanowires have higher
CO tolerance and fast formic acid oxidation kinetics. Also from Fig. 21 c, it can be
seen that the R CT derived from PdAg ANWs is remarkably smaller than that from
the Pd/C catalysts within the studied potential window. The smaller R CT indicates
that the electron-transfer kinetics for formic acid oxidation at the PdAg nanowires
is much better facilitated than that at the Pd/C catalysts. All the results demonstrate
that the as-synthesized PdAg nanowires have much better catalytic performance
than that of commercial Pd/C catalysts.