Oxygen kinetics and mechanism at electrocatalysts on the base of palladium–iron system

CO oxidation as a test reaction for strong metal–support interaction in nanostructured Pd/FeO powder catalysts

“…The integrated amount of the new species of 29% would exactly represent the content of Pd atoms at the surface of the particles in the present Pd particle size, according to the dispersion calculation. Surface alloys like PdFe would also show an energy up-shift, depending on the treatment conditions as described in the literature [46][47][48][49][50], but our IR data did not confirm alloy-induced shifts in the CO wave numbers as reported for example by Felicissimo [9] or Wu et al [23]. In order to confirm enrichment of iron oxide species on the palladium particles during the reduction process, the intensities of Pd and Fe at the surface (E kin = 150-200 eV) and in the bulk (700-800 eV) were integrated at different stages of the reduction, as summarized in table S1 (supplemental).…”

Recent Developments in the Electrocatalysis of the O2Reduction Reaction

“…Recent reports [Fernandez et al, 2005a, b;Lee et al, 2006;Mustain et al, 2007;Raghuveer et al, 2005;Savadogo et al, 2004;Shao et al, 2006aShao et al, , c, 2007bTarasevich et al, 2007;Wang W et al, 2007;Zhang L et al, 2007] have indicated that binary Pd-M alloys (M ¼ Cr, Co, Fe, Ni, Ti) and ternary ones were comparable to, or slightly better than commercial Pt catalysts. These Pd-M catalysts have attracted considerable attention because they are comparatively inexpensive and have very high methanol tolerance, making them promising cathode catalytic materials for hydrogen PEMFCs and especially direct methanol fuel cells (DMFCs).…”

“…However, it is not clear whether O 2 can still easily dissociate after the reactive metal centers are fully occupied by O; besides, the reactive metals on the alloy surface are unstable and leach out rapidly during electrochemical measurements. Thus, these arguments for ORR electrocatalysis on bimetallic surfaces cannot explain the relatively good stability of Pd-M alloys in acidic media [Tarasevich et al, 2007]. The Pd-enriched skin, on the other hand, can account for both the good activity and the stability [Lamas and Balbuena, 2006;Shao et al, 2007a;Suo et al, 2007].…”

Pt decorating of PdNi/C as electrocatalysts for oxygen reduction

“…However, in spite of considerable efforts, to date the parameters and electrochemical stability of majority of non-platinum catalysts for oxygen electrodes are far from the analogous parameters in platinum-containing systems [9]. Another strategy that has been pursued to lower the cost is alloying of Pt with other transition metals, such as Fe, Co, Ni or Cu [10][11][12].…”