Nucleation of nanometer-scale electrocatalyst particles in solid oxide fuel cell anodes

This letter describes a method for forming Ru nanoclusters on oxide anode surfaces during the initial stages of solid oxide fuel cell operation, yielding improved anode performance without additional processing steps. Transmission electron microscope and X-ray photoelectron spectroscopy observations showed that Ru nanoclusters precipitated onto La(0.8)Sr(0.2)Cr(0.82)Ru(0.19)O(3-delta) Surfaces after exposure to hydrogen at 800 degrees C, with Ru cluster size stabilizing at <= 5 nm for the longest times tested, similar to 300 h. Solid oxide fuel cell tests were done in humidified hydrogen at 800 degrees C with La(0.8)Sr(0.2)Cr(0.82)Ru(0.18)O3-delta-GDC (GDC = Gd-doped ceria) anodes on LSGM electrolyte-supported cells. Cell power density increased over the first similar to 50 h of cell operation from similar to 200 to 400 mW cm(-2) due to an anode polarization resistance decrease from similar to 0.6 to < 0.2 Omega cm(2). (c) 2007 Elsevier B.V. All rights reserved.