J. Phys. Chem. C, 111 (50), 18715 -18723, 2007. 10.1021/jp073395i S1932-7447(07)03395-X
Web Release Date: November 22, 2007

Copyright © 2007 American Chemical Society

Characterization of FeS2-Based Thin Films as Model Catalysts for the Oxygen Reduction Reaction

D. Susac, L. Zhu, M. Teo, A. Sode, K. C. Wong, P. C. Wong, R. R. Parsons, D. Bizzotto, K. A. R. Mitchell, and S. A. Campbell*

Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1, Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1, and Ballard Power Systems Inc., 9000 Glenlyon Parkway, Burnaby, British Columbia, Canada V5J 5J8

Received: May 3, 2007

In Final Form: July 31, 2007

Abstract:

FeS2 and (Fe,Co)S2 thin films prepared by magnetron sputtering have been investigated as model catalysts for the oxygen reduction reaction (ORR), and their activities were compared against that of a sputtered thin film of Pt. Scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and micro-Raman spectroscopy have been used, in parallel with electrochemical activity measurements using the thin film as a rotating disk electrode (RDE), to assess how the electrochemical performances of the sulfide films relate to chemical composition and structure. Comparisons were also made against a mineral FeS2 pyrite whose open circuit potential (OCP) was 0.62 V and much less than the values of 0.78 and 0.80 V found for the FeS2 and (Fe,Co)S2 thin films, respectively (all potentials are given vs the reversible hydrogen electrode). There are indications that the ORR activities for these films may be associated with the presence of some polysulfides in addition to the expected S22- bulk and surface sites.

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