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First Principles Computational Study on the Electrochemical Stability of Pt-Co Alloy Nanocatalysts for Fuel Cell Applications

First Principles Computational Study on the Electrochemical Stability of Pt-Co Alloy Nanocatalysts for Fuel Cell Applications
Translated Title
제일원리전산을 이용한 연료전지용 나노스케일 Pt-Co 합금 촉매의 열역학적 구조 분석
Noh, Seung Hyo
DGIST Authors
Noh, Seung Hyo; Han, Byung Chan
Han, Byung Chan
Yoon, Young Gi
Issue Date
Available Date
Degree Date
2013. 2
PtCo catalystDissolutionDurabilityFirst principlesPEMFC연료전지촉매합금내구성제일원리법
Novel design of Pt-M alloy catalysts for a Polymer Electrolyte Fuel Cell (PEMFC) developed over the last decade has substantially not only saved the materials cost but also enhanced oxygen reduction reaction activity. Currently, one of the most challenging issues is how to empower the nanocatalysts electrochemical stability for a wide commercialization of PEMFC as long-term power sources of transportation vehicles. Using first principles and multi-scale computations this thesis investigates the underlying mechanism of the electrochemical degradation of Pt-Co alloy nanocatalysts. The objectives of the thesis are to identify atomic level descriptors of the mechanism and to figure out novel ways to increase the electrochemical durability. To achieve the goals we setup model systems of Pt-Co nanoparticles as function of Co composition and the size of the particle. And then, Monte Carlo simulations combined with the cluster variation method will provide thermodynamically the most stable configuration of Pt-Co alloy catalysts for any given temperature and alloy composition as well as a chemical potential of oxygen atom. To ⓒ 2013 DGIST
Table Of Contents
Chapter 1. Introduction 1 -- 1.1 Introduction to PEM fuel cells 1 -- 1.2 Literature review 5 -- 1.3 Objectives of thesis 9 -- Chapter 2. Computational methodologies 10 -- 2.1 First principles DFT calculations 10 -- 2.2 Cluster expansion theory 10 -- 2.3 Monte Carlo simulation 13 -- 2.4 Model systems 14 -- 2.4.1 Bulk Pt-Co alloys 14 -- 2.4.2 Bulk surface 15 -- 2.4.3 nanoparticles 16 -- 2.5 Computational details 18 -- Chapter 3. Results and discussion 20 -- 3.1 Bulk Pt-Co alloy 20 -- 3.1.1 Ab-initio thermodynamics: energy convex hull 20 -- 3.2 Bulk Pt-Co (111) surfaces 22 -- 3.2.1 Ab-initio thermodynamics: energy convex hull 22 -- 3.2.2 Cluster expansion 22 -- 3.2.3 Monte Carlo simulation of PtCo in an oxygen environment 26 -- 3.3 Pt-Co alloy nanoparticles 28 -- 3.3.1 Ab-initio thermodynamics: energy convex hull 28 -- 3.3.2 Calculation of dissolution potentials 32 -- 3.3.3 Dissolution potential of nanoparticles 34 -- 3.3.4 Adsorbate induced surface segregation 36 -- Chapter 4. Conclusions 41 -- References 42 -- Summary (국문요약) 47
Energy Systems Engineering
Department of Energy Science and EngineeringThesesMaster

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