Adsorption of O2 on Cobalt―(n)Pyrrole Molecules from First-Principles Calculations

In order to clarify the adsorption mechanism of the O2 molecule on Co-polypyrrole composite metallo-organic catalyst, we have investigated the interaction between the molecule and Co-(n)pyrrole model clusters (n=4,6) using the density functional theory. The stable adsorption site of the O2 molecule...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2009-09, Vol.78 (9)
Main Authors: DIPOJONO, Hermawan K, SAPUTRO, Adhitya G, BELKADA, Rachid, NAKANISHI, Hiroshi, KASAI, Hideaki, DAVID, Melanie, DY, Eben Sy
Format: Article
Language:English
Subjects:
Applied sciences
Catalysis
Chemistry
Energy
Energy. Thermal use of fuels
Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc
Exact sciences and technology
Fuel cells
General and physical chemistry
Surface physical chemistry
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
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Summary:In order to clarify the adsorption mechanism of the O2 molecule on Co-polypyrrole composite metallo-organic catalyst, we have investigated the interaction between the molecule and Co-(n)pyrrole model clusters (n=4,6) using the density functional theory. The stable adsorption site of the O2 molecule on Co-(4)pyrrole is found to be at the O-O center of mass located on top of the Co atom in side-on configuration, while for the case of Co-(6)pyrrole cluster, the O2 molecule is slightly deviated from the side-on configuration. The O-O bonds of the O2/Co-(4)pyrrole and the O2/Co-(6)pyrrole systems have elongated by 10.84 and 9.86%, respectively. The elongation mechanism of O2 on Co-(n)pyrrole is induced by the interaction between the cobalt d-orbitals and the O2 anti-bonding π* orbital, which results in a charge transfer from the cobalt atom toward the O2 molecule. This effect seems important in the adsorption of the O2 molecule on Co-(n)pyrrole. It is likely that the extra charge in the O2 molecule would fill its anti-bonding orbital and consequently weaken the O-O bond. In Co-(4)pyrrole, the elongation of the O2 bond is larger than that of Co-(6)pyrrole since a complete side-on configuration has more symmetric overlapping between the cobalt d-orbitals and the O2 anti-bonding orbital.
ISSN:0031-9015
1347-4073