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Analysis of Porphyrines as Catalysts for Electrochemical Reduction of O-2 and Oxidation of H2O

Jakub Baran (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK)) ; Henrik Grönbeck (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK)) ; Anders Hellman (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK))
Journal of the American Chemical Society (0002-7863). Vol. 136 (2014), 4, p. 1320-1326.
[Artikel, refereegranskad vetenskaplig]

Bioinspired structures are promising as improved catalysts for various redox reactions. One example is metal hangman-porphyrines (MHP), which recently have been suggested for oxygen reduction/evolution reaction (ORR/OER). The unique properties of the MHPs are attributed to both the hangman scaffold and the C6F5 side groups. Herein, the OER/ORR over various transition metal MHPs is investigated by density functional theory calculations within an electrochemical framework. A comparison of the reaction landscape for MHP, metal porphyrine (MP) and metaltetrafluorophenyloporphyrines (MTFPP), allow for a disentanglement of the different roles of the hangman motif and the side groups. In agreement with experimental studies, it is found that Fe and Co are the best MHP Metal centers to catalyze these reactions. We find that the addition of the three-dimensional moiety in the form of hangman scaffold does not break the apparently universal energy relation between *OH and *OOH intermediates. However, the hangman motif is found to stabilize the oxygen intermediate, whereas addition of C6F5 groups reduces the binding energy of all reaction intermediates. Our results indicate that the combination of these two effects allow new design possibilities for macromolecular systems with enhanced catalytic OER/ORR activity.

Nyckelord: FUNCTIONALIZED GRAPHITIC MATERIALS, FUEL-CELL CATHODE, OXYGEN REDUCTION, TRANSITION-METAL, HANGMAN PORPHYRINS, WATER OXIDATION, OXIDE SURFACES, DENSITY, EVOLUTION, HYDROGEN



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Denna post skapades 2014-03-17. Senast ändrad 2015-03-30.
CPL Pubid: 195127

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kemisk fysik (1900-2015)
Kompetenscentrum katalys (KCK)

Ämnesområden

Energi
Materialvetenskap
Nanovetenskap och nanoteknik
Transport
Kemi

Chalmers infrastruktur

C3SE/SNIC (Chalmers Centre for Computational Science and Engineering)