Electrocatalytic Reduction of Oxygen by FePt Alloy Nanoparticles

Abstract

Fe x Pt100- x nanoparticles of different compositions (x = 63, 58, 54, 42, 15, and 0) were prepared and loaded onto a glassy carbon (GC) electrode where their catalytic activities in the electroreduction of oxygen were examined and compared. Cyclic and rotating disk voltammetric studies of the resulting Fe x Pt100- x /GC electrodes showed that the catalytic activity for oxygen reduction exhibited a peak-shape dependence on the particle composition (x). Among the series of nanocatalysts under study, Fe42Pt58 particles showed the maximum activity for O2 reduction in terms of the reduction overpotential and current density. This was accounted for by the effects of the Fe content on the electronic structures of the Pt active sites and the resulting Pt−O interactions. Kinetic analyses showed that direct four-electron reduction of adsorbed oxygen occurred on these catalyst surfaces. Additionally, the rate constant of O2 reduction increased with increasing Pt content in the alloy particles; yet, at x ≤ 42, the rate constant exhibited only a very small increment. These studies suggest that the Fe42Pt58 particles might represent an optimal composition for oxygen reduction among the series of nanoparticle catalysts under the present study.

Oxygen Electroreduction Catalyzed by Gold Nanoclusters: Strong Core Size Effects

“…Figure 3 A shows the rotatingdisk voltammograms of oxygen reduction recorded at the Au 11 /GC electrode in an oxygen-saturated 0.1m KOH solution at different rotation rates (from 225 to 3600 rpm). The current density plateaus are much better defined than those with larger Au nanoparticles; [13,29] overall, the voltammetric profiles are similar to those observed with Pt (or Pt-alloy)-based electrodes, [4] in which the current density increases with increasing rotation rates. The onset potential of oxygen reduction can be found to be approximately À0.1 V, which is close to that obtained from cyclic voltammetric measurements in Figure 2 (À0.08 V).…”

Oxygen Reduction Activity and Durability of Ordered and Disordered Pt3Co Alloy Nanoparticle Catalysts at Practical Temperatures of Polymer Electrolyte Fuel Cells

“…2∼7 times compared to that of pure Pt. The enhancement factor has been found to depend on various properties of alloy nanoparticles, e.g., composition, 4,[14][15][16] shape (or size), [17][18][19][20][21] and crystal structure. [22][23][24][25][26][27][28][29] For example, the values of j k for Pt-Co alloys showed a maximum at the atomic ratio of Pt/Co = 3.…”

Direct Ethanol Fuel Cell on Carbon Supported Pt Based Nanocatalysts

“…To overcome this electrochemical voltage loss, catalysis of oxygen reduction requires a high platinum loading (typically 0.1-0.5 mg cm À2 ) in fuel cell cathodes [119]. The oxygen reduction reaction has been analyzed on carbon supported platinum (Pt/C) electrocatalysts in 0.1 mol L À1 HClO 4 through cyclic voltammetry (CV) [120,121] and rotating disk electrode (RDE) [60,84,[122][123][124] techniques. Electrochemical rotating disk electrode (RDE) experiments were conducted in a conventional three-electrode electrochemical cell in 0.1 mol L À1 HClO 4 .…”