APS March Meeting 2012
Volume 57, Number 1
Monday–Friday, February 27–March 2 2012;
Boston, Massachusetts
Session D26: Focus Session: Physics of Energy Storage Materials - Catalysis and H2 Storage
2:30 PM–5:30 PM,
Monday, February 27, 2012
Room: 257B
Sponsoring
Units:
DCOMP DMP
Chair: Juergen Eckert, University of California, Santa Barbara
Abstract ID: BAPS.2012.MAR.D26.1
Abstract: D26.00001 : Design Principles for Oxygen Reduction and Evolution on Oxide Catalysts
2:30 PM–3:06 PM
Preview Abstract
Abstract
Author:
Yang Shao-Horn
(Massachusetts Institute of Technology)
Driven by growing concerns about global warming and the depletion of
petroleum resources, developing renewable energy production and storage
technologies represent one of the major scientific challenges of the
21$^{st}$ century. A critical element in pursuit of this quest is the
discovery of efficient and cost-effective catalysts used in solar fuel
production via electrochemical energy conversion processes such as oxygen
evolution reaction (OER) and oxygen reduction reaction (ORR), both of which
are central to the efficiencies of direct{\-}solar and electrolytic
water-splitting devices, fuel cells, and metal-air batteries. Although the
Sabatier's principle provides a qualitative argument in tuning catalytic
activity by varying the bond strength between catalyst surface and
reactant/product (neither too strong nor too weak leading to the maximum
activity at moderate bond strength), it has no predictive power to find
catalysts with enhanced activity. Identifying a ``design principle'' that
links catalyst properties to the catalytic activity is critical to
accelerate the search for highly active catalysts based on abundant
elements, and minimize the use of precious metals.
Here we establish a molecular principle that governs the activities of
oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) for
oxide catalysts, where the activities primarily correlate to the $\sigma $*
orbital (``e$_{g}$'') occupation of surface transition{\-}metal cations
established by systematic examination of more than ten to fifteen
transition{\-}metal oxides. The intrinsic ORR and OER activities exhibit a
volcano-shaped dependence on the e$_{g}$ occupancy and the activities peak
at an e$_{g}$ occupancy close to unity. Our findings reflect the critical
influence of the $\sigma $* orbital on the energetics of surface reaction
intermediates on surface transition metal ions such as the
O$_{2}^{2-}$/OH$^{-}$ displacement and the OH$^{-}$ regeneration, and thus
highlight the importance of surface oxide electronic structure in
controlling catalytic activities. Using the established molecular principle,
we further demonstrate that an alkaline earth cobalt oxide with a chemical
formula of Ba$_{0.5}$Sr$_{0.5}$Co$_{0.8}$Fe$_{0.2}$O$_{3{\-}\delta }$
(BSCF), catalyzes the OER with intrinsic activity that is at least an order
of magnitude higher than the state-of-the-art iridium oxide catalyst in
basic solutions.
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[1] J. Suntivich, H.A. Gasteiger, N. Yabuuchi, H. Nakanishi, J. B. Goodenough and Y. Shao-Horn, Design Principles for Oxygen Reduction Activity on Perovskite Oxide Catalysts for Fuel Cells and Metal-Air Batteries, Nature Chemistry, \underline {3}, 546--550 (2011).\\[0pt]
[2] Jin Suntivich, Kevin J. May, Hubert A. Gasteiger, John B. Goodenough and Yang Shao-Horn, A Perovskite Oxide Optimized for Oxygen Evolution Catalysis from Molecular Orbital Principles, ScienceExpress, Science DOI: 10.1126/science.1212858, (2011).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.D26.1