PHYS 203 |
| While experiments in surface science or basic electrochemistry are predominantly performed on single crystals, realistic fuel cells employ highly-dispersed nanoparticles to catalyze the occurring reactions. However, those combine a variety of different functional groups on their surfaces (planes, step-edges, or kinks), making it difficult to transfer effects observed in single crystal electrochemistry to realistic systems directly. Here faceting of single crystal surfaces, leading to homogeneous and well-defined nanostructures, might be a possibility to bridge the gap between nanoparticles and extended surfaces. Motivated by the UHV-experiments in the group of Madey, we used density functional theory calculations in combination with our newly formulated extension of the ab initio atomistic thermodynamics approach to generate (p/T/Φ)-phase diagrams for the facet formation on Ir(210)- and Re(11-21)-surfaces. The calculated phase diagrams exactly reveal the experimentally found structures and predict that applying an electrode potential might induce facet formation on these rough surfaces. By this potential-induced formation of self-assembled nanostructures, one might be able to obtain deeper insights into the catalytic behavior of nanoparticles in electrocatalysis. |
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Computational Electrochemistry for New Energy
8:20 AM-11:55 AM, Tuesday, August 21, 2007 BCEC -- 160C, Oral
Division of Physical Chemistry |