The promise of polymer electrolyte membrane fuel cells (PEMFCs) as a future energy conversion device is severely limited by the electrocatalysts used, often with high Pt content and slow reaction kinetics. Highly faceted nanoparticles have demonstrated favorable activity, however the fundamentals of the enhanced behavior are not understood. We have used Re and Ir single crystal model systems with well-defined faceting to provide fundamental insight into the activity of these surfaces. Re(11-21) becomes covered with three-sided pyramids with facets of (01-11), (10-11) and (11-20) orientation upon heating in acetylene at 700 K. Ir(210) facets to three-sided pyramids of (311), (31-1) and (110) orientations after heating in O2. We report here on observations that a faceted C/Re substrate with a Pt monolayer demonstrates higher activity for the hydrogen evolution reaction than a Pt(111) surface.

Nanofaceted model electrocatalysts

244th National Meeting (2012)

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