Chapter 1 Proton Exchange Membrane Fuel Cells (PEMFCs) 1.1 Introduction 1.2 PEMFC Components 1.3 Membrane Electrode Assembly (MEA) 1.3.1 MEA Structure 1.3.2 Proton Exchange Membrane (PEM) 1.3.3 Catalyst Laver 1.3.4 Gas Diffusion Layer (GDL) 1.4 Electrocatalysts 1.4.1 Pt/C Catalysts 1.4.2 Pt Alloy/C Catalysts 1.4.3 Core-Shell Catalysts 1.4.4 Shape-Controlled Pt-Based Nanocrystals 1.4.5 Nonprecious Metal Catalysts (NPMC) 1.5 Summary References Chapter 2 The Electrocatalysis of Oxygen Reduction on Platinum and Its Alloys 2.1 Introduction 2.1.1 Cathode Reaction 2.1.2 Platinum and Platinum-Based Catalysts 2.2 Reac Reaction Mechanism 2.2.1 The Dissociation Mechanism and the Association Mechanism 2.2.2 Theoretical Analysis on Pt Activity Toward the ORR 2.3 Electrochemical Measurements 2.4 Further Improvement Toward Pt Activity 2.4.1 Pt Nanonartielee"uuu 2.4.2 An Organic Solvent System-Assisted Electrodeposition of Highly Active p "y 2.5 Pt-Based Alloys 2.5.1 Theoretical Analysis on Pt-Based Alloys Activity Toward the ORR 2.5.2 Composiftion Effects 2.5.3 The Co-Reduction of Pt with Co lons 2.5.4 Crystallographic Orientation Effects 2.5.5 Icosahedral Pt-Ni Nanocrystalline Electrocatahst 2.5.6 Stability 2.5.7 Thermal Annealing Synthesis of Double-Shell Truncated Octahedral Pt_Ni Allovs 2.6 Outlook References Chapter 3 Pt-MS Electrocatalysts for ORR 3.1 Introduction 3.2 Cu UPD Coupled with Pi2+ Galvanic Replacement 3.3 Pt MSs on Single-Crystal Metal Electrodes for ORR 3.3.1 Efects of Substrates on Pt MSs for ORR 3.3.2 Volcano-Type Relation Berween Electrocatalytic Activity and d-Band Center for ORR on Pt MS 3.3.3 Summary 3.4 Pt MSs on Pd(111) and Carbon-Supported Pd NPs for ORR 3.4.1 Pt MSs Deposited on Pd(111) and Pd NPs 3.4.2 P MS on a Pd(111) Surface for ORR 3.4.3 Pt MSs on Carbon-Supported Pd NPs for ORR 3.4.4 Fuel Cell Tests for Pt-MS Electrocatalysts 3.4.5 Discussion 3.4.6 Summary 3.5 Mixed Pt-M-MS Electrocatalysts for ORR 3.5.1 ORR on Mo2wn/Pt(l11) 3.5.2 ORR on (M o2Pto8)M/Pd(111) 3.5.3 ORR on (Ma sPtos)ur/Pd NPs/C 3.5.4 Summary 3.6 Pt MSs on Carbon-Supported Au-Ni NPs for ORR 3.6 .I Electrochemical and XRD Characterization of Au/Ni NPs 3.6.2 ORR Electrocatalytic Properties 3.6.3 Fuel Cell Tests 3.6.4 XANES Measurements 3.6.5 Discussion 3.6.6 Summary 3.7 Pt MSs on Carbon-Supported PdNi1-x NSs for ORR 3.7 .I Phvsicachemical Characterizations of Pd, Ni1 and PdxNi1-x@Pt NSs 3.7.2 Greatly Enhanced Pd Utilization for the Cu UPD On PdxNi1-x@Pt NSs 3.7.3 ORR Electrocatalytic Properties 3.7.4 Summary Reference Chapter 4 Membrane Electrode Assembly (MEA) 4.1 Introduction 4.1 .I Reaction and Mass Transport Process in Fuel Cells 4.1.2 Structure in CLs and Iis Characterization 4.2 Proton Transport in Electrode 4.3 Oxygen Transport in Electrode 4.3.1 Local and Bulk Oxygen Transport in CLs 4.3.2 Experimental Measurement of Local and Bulk Oxygen Transport Resistance .vy 4.3.3 Influence of Ionomer Content on Local and Bulk Oxygen Transport Resistance 4.3.4 Mechanism oj Bulk Uaygen Iransport Behavior 4.3.5 Mechanism of Local Oxygen Transport Behavior 4.4 Cation Contamination in Electrode- r References Chapter 5 Degradation of Pt-Based Catalysts in PE MFC 5.1 Introduction 5.2 Pi Deoradation 5.2.1 pt Deeradation Mechanisms 5.2.2 Experimental Observation of Pt Degradation 5.2.3 Mathematical Modeling of Pt Degradation 5.2.4 Mitigation Strategies for Pt Degradation in the Cathode 5.3 Pt-Based Alloy Degradation 5.3.1 Pt-Based Alloy Degradation