Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 89 for “"oxygen reduction reaction (ORR)"”.
-
DFT insight into the oxygen reduction reaction (ORR) on the Pt₃Co(111) surface
… PEMFC is a Pt-catalyst. However, due to the slow oxygen reduction reaction (ORR) kinetics, high Pt loadings have to be used. The high Pt loadings lead to high costs of the PEMFC. Pt-Co alloys have been identified as catalysts having higher ORR activity higher than of a Pt-catalyst. Therefore, in …
-
The mobility of oxygen containing species (OCS*) over Pt-based catalyst surfaces: Impact on the oxygen reduction reaction (ORR) activity
… facing PEMFCs is the sluggish kinetics of the oxygen reduction reaction (ORR). To further enable wide-scale commercialisation of PEMFCs for automotive applications, major improvements in the ORR catalyst are therefore needed. An in depth understanding of the ORR mechanism over Pt surfaces can …
-
Facilitating, understanding, and controlling the oxygen reduction reaction for fuel cell technology using (1) laccase-inspired tricopper molecular catalysts, (2) a high temperature and pressure reaction vessel, and (3) a hybrid bilayer membrane electrochemical platform
… were to investigate three major facets of the oxygen reduction reaction (ORR: O2 + 4 H+ + 4 e– → 2 H2O). First, I developed new tri-copper catalysts for the ORR with a specific focus on the active site present in multi-copper oxidases, which are the most active enzymes for the ORR. Second, I …
-
A Study Of Electrocatalysis In The Oxygen Reduction Reaction Using OpenCatalyst, a Deep-Learning Platform.
… (PEMFCs) is fundamentally influenced by the Oxygen Reduction Reaction (ORR) at the cathode. This dissertation presents a comprehensive investigation into the ORR kinetics and mechanism, with a specific focus on the electrocatalytic properties of bimetallic catalysts—particularly palladiumgold …
-
Exploring Reactive Species in the Mechanism of Oxygen Reduction using Pentadentate Ligand-Supported Cobalt Complexes
… cobalt(III) complex was explored. The binding of oxygen was found to be reversible and that the O2 was activated towards protonation and that reduction of the products lead back to cobalt(II). The relevance of this chemistry to the Oxygen Reduction Reaction (ORR) was discussed. The catalytic …
-
Development of electronic structure and kinetics methods for the rational design of electrocatalysts
… theory (BET) and its ability to recover static correlation, as well as a proof on BET's ideal convergence properties. We then present a theoretical analysis using density functional theory (DFT) on a class of GCCs containing cationic nitrogen atoms, which are particularly active for catalyzing …
-
Oxygen reduction on platinum : an EIS study
The oxygen reduction reaction (ORR) on platinum over yttria-stabilized zirconia (YSZ) is examined via electrochemical impedance spectroscopy (EIS) for oxygen partial pressures between 10-4 and 1 atm and at temperatures between 475 and 700°C. Use of photolithographic techniques in electrode …
-
Stability of double perovskite cathodes under high humidity for solid oxide fuel cells
… (and carbon dioxide). However, the kinetics of oxygen reduction reaction (ORR) on the cathode is often hindered by various contaminants, which may react with the cathode to form insulating phases and degrade fuel cell performance. The stability and performance of the cathode in moisture is …
-
Understanding and controlling the reactivity of oxygen reduction and methanol oxidation electrocatalysts
… devices like fuel cells, is essential. The oxygen reduction reaction (ORR) at the fuel cell cathode and the methanol oxidation reaction (MOR) at the anode serve as prime examples of electrocatalytic reactions requiring deeper mechanistic insights and advancements in effective …
-
EXPLORATION OF TM-NX ORR ELECTROCATALYSTS FROM FIRST PRINCIPLE CALCULATIONS
… the power generation is limited by the sluggish oxygen reduction reaction (ORR) at the cathode. An interesting alternative material set which continues to attract significant attention are TM-Nx (TM = Fe, Co, x = 2 - 4) based non-PGM electrocatalysts where the defect motifs are embedded in a …
-
Development of a semi–empirical reaction kinetic model for PEM fuel cells
… at the cathode are due to the activation of the oxygen reduction reaction (ORR). To reduce the platinum content requirements and understand the cause of the large overpotential of the ORR, a fundamental understanding of the reaction mechanism and the manner in which it proceeds under different …
-
A comparative study of PtCo/C Alloys and Pt/C as cathode catalysts for fuel cell applications
… improved activity, particularly for the cathodic oxygen reduction reaction (ORR), and stability over commercial platinum only catalysts. This requires a detailed understanding of both desirable catalyst structure and mechanistic activity. In this work a comparative study is made between commercial …
-
Mechanism of oxygen reduction reaction on transition metal oxide catalysts for high temperature fuel cells
… due to the poor catalytic activity of the oxygen reducing cathode. This thesis research is focused on identifying the fundamental reaction mechanisms and pathways for oxygen reduction reaction (ORR) in transition metal oxide cathodes to enable lower operating temperature and improve device …
-
Electrochemical analysis of active species in a low iron content oxygen reduction reaction catalyst and aluminium covetic materials
… increase fuel cell efficiency is to improve the oxygen reduction reaction (ORR) catalyst so that Pt is no longer used. Changing catalysts has proven to be difficult since it is not understood how the reaction proceeds on a non-precious metal (NPM). In the current work, a low Fe content, high …
-
OPERANDO X-RAY ABSORPTION SPECTROSCOPY STUDIES OF (PHOTO)ELECTRODE MATERIALS FOR H2 PRODUCTION/CONVERSION
… this sense, it involves various electrochemical reactions, and one of the main tasks is understanding the reaction mechanisms in the reaction process to rationally design high-efficiency electrodes. Therefore, this thesis is focused on this topic. In this thesis, the works mainly contain 3 parts: …
-
Surface phase emergence and evolution of solid oxide fuel cell cathode materials
… A limiting factor for SOFC performance is the oxygen reduction reaction (ORR) that occurs at cathode surface. This research involves the study of changes in the surface composition and structure at the surface of the cathode, since these changes can directly influence the ORR. Idealized single …
-
Preparation and characterisation of inorganic nanostructured support materials for polymer electrolyte fuel cells
… platinum (Pt/C) catalysts. Carbon support corrosion and Pt dissolution/aggregation on the catalyst layer within the fuel cell have been confirmed as the major contributors to the degradation of the Pt/C (Shao, et al., 2007). Attention needs to be paid to the improvement of catalyst …
-
Adsorption of oxygen molecules on platinum surfaces modified with subsurface atoms of vanadium : a DFT study
… development of hydrogen fuel cells, because the oxygen reduction reaction (ORR) presently requires O2 adsorption to occur on pure platinum, which is a prohibitively expensive material. A computational study has therefore been undertaken on alloying platinum (which reduces cost) with vanadium (for …
-
Rapid screening of PEM FC cathode catalysts
… systems for screening catalysts used for the oxygen reduction reaction (ORR) at the cathode of PEMFCs. The first system developed was the 64 channel pin electrode array, using liquid electrolyte. The developed method improved both the quality and reproducibility of the data and has been used …
Page 1 of 5