Nonprecious Metal Catalysts for Low Temperature Solid Oxide Fuel Cells

By Holme, Timothy P. & Prinz, Fritz B.
Published in The Journal of Physical Chemistry C NULL 2011

Abstract

Density functional theory was used to design a non-noble metal catalyst for low temperature oxygen reduction. A core -shell catalyst of Ag|AgxCu5-xZn8 was found to have an electronic structure predicted to be near optimal for weak oxygen bonding, and the activation energy for dissociation was low. This catalyst was made via evaporation and sputtering and tested as the anode and cathode of low temperature solid oxide fuel cells. The new catalyst showed charge transfer resistance 16 times higher than platinum on the cathode side, and five times lower on the anode side at 400 °C. The resistance to common catalyst poisons CO and H2S is enhanced compared to Pt. Further, the catalyst was tested as the cathode of a proton exchange membrane fuel cell by testing the half cell reaction in a rotating disk electrode. The exchange current density was within a factor of 3 lower than Pt, while the charge transfer coefficient was a factor of 3 higher than Pt. The Ag|AgxCu5-xZn8 catalyst is a promising start to develop non-noble metal catalysts.

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