Naomi Levy, Atif Mahammed, Monica Kosa, Dan T. Major, Zeev Gross,* and Lior Elbaz*
Angewandte Chemie International Edition
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
DOI: 10.1002/anie.201505236
http://onlinelibrary.wiley.com/doi/10.1002/anie.201505236/abstract
Abstract
The future of
affordable fuel cells strongly relies on the design of earth-abundant
(non-platinum) catalysts for the electrochemical oxygen reduction
reaction (ORR). However, the bottleneck in the overall process occurs
therein. We have examined herein trivalent Mn, Fe, Co, Ni, and Cu
complexes of β-pyrrole-brominated corrole as ORR catalysts. The
adsorption of these complexes on a high-surface-area carbon powder
(BP2000) created a unique composite material, used for electrochemical
measurements in acidic aqueous solutions. These experiments disclosed a
clear dependence of the catalytic activity on the metal center of the
complexes, in the order of Co>Fe>Ni>Mn>Cu. The best
catalytic performance was obtained for the CoIII corrole,
whose onset potential was as positive as 0.81 V versus the reversible
hydrogen electrode (RHE). Insight into the properties of these systems
was gained by spectroscopic and computational characterization of the
reduced and oxidized forms of the metallocorroles.
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