Publicação: Well-Alloyed PtFe/C Nanocatalysts of Controlled Composition and Same Particle Size: Oxygen Reduction and Methanol Tolerance
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Electrochemical Soc Inc
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A study of the effect of iron concentration on the electrocatalysis of oxygen reduction reaction (ORR) on well-alloyed carbon-supported PtFe nanocatalysts with a controlled iron content and the same particle size is presented. To obtain the catalysts for this study, PtFe nanoparticles of different compositions were first obtained in a colloidal state in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)+n-butanol/n-heptane/water microemulsions and subsequently supported in high surface area carbon powder. Transmission electron microscopy evidenced that all PtFe/C nanocatalysts prepared are monodispersed and have nearly the same average particle size. X-ray diffraction studies showed that the lattice parameter of these PtFe/C catalysts varies linearly with iron content up to 50% (in atoms), while the compositions of the alloyed phases estimated by using Vegard's law are almost identical to the nominal values, indicating a high degree of alloying. The electrocatalytic activity for ORR of these catalysts was studied using the rotating disk electrode technique in O(2) saturated 0.5 mol L(-1) H(2)SO(4) solutions, while methanol tolerance was evaluated from curves taken in acid solutions containing 0.1 mol L(-1) methanol. The results reported here reflect the dependence of the electrocatalytic activity for the ORR on iron concentration in the absence of particle size effects and metal segregation.
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carbon, catalysts, colloids, electrochemical electrodes, iron alloys, lattice constants, microemulsions, nanoparticles, nanotechnology, particle size, platinum alloys, reduction (chemical), segregation, transmission electron microscopy, X-ray diffraction
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Inglês
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Journal of The Electrochemical Society. Pennington: Electrochemical Soc Inc, v. 156, n. 1, p. B51-B58, 2009.
