Catalytic Properties of Transition Metal鈥揘4 Moieties in Graphene for the Oxygen Reduction Reaction: Evidence of Spin-Dependent Mechanisms
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- 作者：Walter Orellana
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：May 16, 2013
- 年：2013
- 卷：117
- 期：19
- 页码：9812-9818
- 全文大小：382K
- 年卷期：v.117,no.19(May 16, 2013)
- ISSN：1932-7455
文摘
The O2 dissociation after the chemisorption on the metal center of M鈥揘4 moieties in graphene (with M = Mn, Fe, and Co) is addressed by density functional theory calculations. Both minimum energy paths and saddle points for the oxygen reduction reaction (ORR) in the allowed spin states have been identified. Our calculations indicate that ORR can evolve through different spin states, those where the M鈥揙2 adducts are stable. We find that Mn鈥揘4 and Fe鈥揘4 centers in graphene exhibit the lowest O2 dissociation energies of 0.7 and 1.1 eV, respectively, over three spin channels, while for Co鈥揘4 we find two spin channels with the same dissociation energy of 1.6 eV. The O2 dissociation barriers on the Mn鈥揘4 and Fe鈥揘4 centers are comparable to that found on Pt(111), suggesting similar ORR catalytic activity, in agreement with experimental results.