First principles study of effect of surface structure on chemical activity of Pt electrocatalysts in fuel cells
Name
275164929-MIT.pdf
Description
Full printable version
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22.42 MB
Format
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Checksum (MD5)
81a3246d7b4819ef6aadd319b21a9eec
Author(s)
Han, Byungchan
Advisor(s)
Gerbrand Ceder.
Date Issued
2008
Publisher
Massachusetts Institute of Technology
Abstract
To facilitate commercialization of fuel cell systems as alternative energy device, the enhancement of Pt electrocatalysts activity is one of the most challenging issues. The first step to the solution is elucidating relationship between surface structure and chemical reactivity as electrocatalysis occurs on its surface. However, in spite of concerted experimental and theoretical research over the last decades, the detailed mechanism is still in debate. This thesis explores a structural sensitivity of the chemical reactivity in the Pt-based alloy electrocatalysts by combining ab-initio density functional theory (DFT) with relevant thermodynamic and kinetic approach. We developed a rigorous statistical mechanical formalism, which can parameterize the energetics obtained by first principles calculations as a function of surface topologies. This methodology enables kinetic Monte Carlo simulations to provide thermally equilibrated structures as a function of partial pressures of adsorbates and alloy compositions. With our consistent methods, we characterize surface structures on the atomic scale, and quantify chemical reactivity of various Pt-alloy model systems. Our methodology reproduced accurate and consistent results of available experimental measurements. We find that our methodology is considerably useful for studying the structural effect on the heterogeneous catalysis. Through the thesis, we understood better how surface structures evolve according to environmental conditions and hence, the structure-activity relationship, which is useful for design of electrocatalysts.
Description
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.
Includes bibliographical references (p. 154-165).
Subjects
Materials Science and Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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