Rotating Disk Slurry Electrodeposition (RoDSE) Technique for Fuel Cell Catalysts Development

Abstract

The Rotating Disk Slurry Electrodeposition (RoDSE) technique is a novel method which can electrochemically deposit metal nanoparticles on a given conductive support and produce a powder catalyst for diverse applications, e.g. ethanol oxidation reaction (EOR). This technique was used to electrodeposit Pd nanoparticles on carbon Vulcan XC–72R nanoflakes at three different applied potentials (0.0, 0.4, and 0.7 V vs. RHE). The potentials were chosen to represent different thermodynamic and kinetic regions of Pd electrodeposition. Each Pd /Vulcan catalyst was characterized through different spectroscopic, microscopic, and electrochemical techniques. Powder X–ray diffraction and transmission electron microscopy studies verified the Pd crystallinity and particle size, respectively. The Pd particle size decreased with a more positive applied electrodeposition potential at carbon Vulcan XC–72R nanoflakes. X-ray photoelectron spectroscopy determined that the applied potential affected, both, the final palladium and carbon oxidation states. Finally, cyclic voltammetry was used to characterize the electrocatalytic activity of each Pd / Vulcan catalyst in 0.1M KOH and for the EOR. It was found that, for Pd electrodeposition using RoDSE, an applied potential of 0.4 V vs. RHE provided considerable harmony between a mass transport and kinetically controlled deposition thereby providing the optimal conditions for a better EOR catalyst. Figure 1