Near surface decoration of Sr1-xYx TiO3 with transition metals for controlling the SOFC anode reactions: Firstprinciples study

Title
Near surface decoration of Sr1-xYx TiO3 with transition metals for controlling the SOFC anode reactions: Firstprinciples study
Authors
함형철김희수임동희윤창원윤성필한종희남석우
Keywords
DFT; H2S; SOFC; anode
Issue Date
2013-04
Publisher
245th ACS National Meeting
Abstract
In recent years, the yttrium-doped strontium titanium oxide (Sr0.92Y0.08TiO3; SYT) has received much attention as an alternative anode material for solid oxide fuel cell (SOFC) due to its high sulfur/carbon resistance, good electronic/ionic conductivity and phase stability in typical SOFC anode operating conditions. However, SYT has exhibited the poor electro-catalytic activity toward fuel (i.e. H2 or CH4) oxidation. Thus, it is very essential to understand the factors controlling the reactivity of SYT toward SOFC anode reactions for developing effective SYT-based anode materials. In this talk, we will present some recent theoretical results we have on the role of the chemical nature of oxygen species bonded with neighboring transition metals at near surface in determining the reactivity of SYT anode toward fuel (such as H2) oxidation. Using spin-polarized density functional theory calculations for geometric and electronic structures, we find that the fuel oxidation reaction [(e.g.) for H2 oxidation, H2+O(surface) → OH+OH → H2O+ O(vacancy)] in Sr1-xYxTiO3 anode strongly depends on the surface oxygen vacancy formation energy. Our calculations also show that such vacancy formation energy can be controlled by decorating the near surface region of SYT with transition metals. This work hints the importance of knowing how to properly tailor the surface reactivity of oxide-based anode materials for achieving wanted electro-catalytic activity for SOFC application.
URI
http://pubs.kist.re.kr/handle/201004/46580
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KIST Publication > Conference Paper
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