The transfer of electrons to and from a molecule is one of the more fundamental and important chemical processes. One such important example is the reduction-oxidation (redox) cycles in catalysts and enzymes. In the hydrogenase enzymes, adding and removing electrons is one of the key processes for generating H2 from water molecules. Finding a direct free energy relation between the vertical ionization energies (IEV) measured spectroscopically by gas-phase photoelectron spectroscopy and the oxidation potentials (E1/2) measured thermodynamically in solution by cyclic voltammetry (CV) for molecules is an important aspect for developing effective catalysts. In this study, a series of organometallic compounds such as metallocenes were used for investigating the free energy relationships and catalysts inspired by the active sites of [FeFe]-hydrogenases enzymes were evaluated for their ability to produce H2 from electrocatalytic reduction of weak acids. The first part of the dissertation explores metallocenes of the form (ç5 C5H5)2M (M= Fe, Ru, Os, Co, Ni) as the model for developing the free energy relation between gas phase ionization energies (IEV) and solution oxidation potentials (E1/2). It was found that computing the electronic properties of Cp2Fe, Cp2Ru, and Cp2Os using VWN-Stoll and OPBE density functional theory (DFT) functional was successful with root mean square deviation (RMSD) of 0.02 eV between the experimental and calculated ionization energies. However, calculated ionization energies of Cp2Co and Cp2Ni were less successful with RMSD of 0.3 eV between the experimental and calculated ionization energies. Introduction of the B3LYP or M06 hybrid DFT functionals yielded much improved results (0.1 eV) over the previous combinations of DFT functional for Cp2Co and Cp2Ni. The energy relation between the two experimental measurements was established and further computational studies revealed that the solvation energy was the largest energy contribution between IEV and E1/2 in the five studied metallocenes. The RMSD of the calculated oxidation potentials, after adjusting for the error in gas phase ionization energies, was 0.09 V. The second part of the dissertation explores a series of catalysts inspired by the active sites of [FeFe]-hydrogenase enzymes; ì-(2,3-pyrazinedithiolato)diironhexacarbonyl (PzDT-cat), Fe2(ì-X2C5H8O)(CO)6 (where X = S, Se, Te), and Fe2(ì-1,3-SC3H6X)(CO)6 (where X = Se and Te) for their ability to produce H2 from weak acids utilizing the computational techniques and knowledge gained from the metallocene study. Even though the overall electronic perturbation from ì-(1,2-benzenedithiolato)diironhexacarbonyl (BDT-cat) to ì-(2,3-pyridinedithiolato)diironhexacarbonyl (PyDT-cat) to PzDT-cat is found to be small, the reduction potential of PzDT-cat was found to be 0.15 V less negative than that of BDT-cat resulting in less energy required for initiating electrocatalytic H2 production over the BDT-cat and PyDT-cat. Lower reorganization energy has been achieved by substitutions of larger chalcogens at the Fe2S2 core. However, the electrocatalytic production of H2 from acetic acid in acetonitrile was found to be diminished upon going from analogous S to Se to Te species. This is ascribed to the increase in the Fe-Fe bond distance with a corresponding increase in the size of the chalcogen atoms from S to Se to Te, disfavoring the formation of a carbonyl-bridged structure in the anion which is thought to be critical to the mechanism of H2 production.

Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.

Heterogeneous catalysis provides the backbone of the world's chemical and oil industries. The innate complexity of practical catalytic systems suggests that useful progress should be achievable by investigating key aspects of catalysis by experimental studies on idealised model systems. Thin films and supported clusters are two promising types of model system that can be used for this purpose, since they mimic important aspects of the properties of practical dispersed catalysts. Similarly, appropriate theoretical studies of chemisorption and surface reaction clusters or extended slab systems can provide valuable information on the factors that underlie bonding and catalytic activity. This volume describes such experimental and theoretical approaches to the surface chemistry and catalytic behaviour of metals, metal oxides and metal/metal oxide systems. An introduction to the principles and main themes of heterogeneous catalysis is followed by detailed accounts of the application of modern experimental and theoretical techniques to fundamental problems. The application of advanced experimental methods is complemented by a full description of theoretical procedures, including Hartree-Fock, density functional and similar techniques. The relative merits of the various approaches are considered and directions for future progress are indicated.

Provides a comprehensive practical review of the new technologies used to obtain hydrogen more efficiently via catalytic, electrochemical, bio- and photohydrogen production. Hydrogen has been gaining more attention in both transportation and stationary power applications. Fuel cell-powered cars are on the roads and the automotive industry is demanding feasible and efficient technologies to produce hydrogen. The principles and methods described herein lead to reasonable mitigation of the great majority of problems associated with hydrogen production technologies. The chapters in this book are written by distinguished authors who have extensive experience in their fields, and readers will have a chance to compare the fundamental production techniques and learn about the pros and cons of these technologies. The book is organized into three parts. Part I shows the catalytic and electrochemical principles involved in hydrogen production technologies. Part II addresses hydrogen production from electrochemically active bacteria (EAB) by decomposing organic compound into hydrogen in microbial electrolysis cells (MECs). The final part of the book is concerned with photohydrogen generation. Recent developments in the area of semiconductor-based nanomaterials, specifically semiconductor oxides, nitrides and metal free semiconductor-based nanomaterials for photocatalytic hydrogen production are extensively discussed.

This book provides a guide for professionals interested in energy transfer and electrochemical technology systems. It covers the state-of-the-art of materials, electrochemistry and electrochemical engineering as related to electrochemical reactors, batteries and fuel cells. The fifteen chapters, written by experts in fields related to every aspect affecting reactor performance, are grouped into three parts. The first is devoted to fundamentals of reactors, batteries and fuel cells and covers various aspects of design, parts, construction, materials operation and control systems. The second group is devoted to specific reactors such as aqueous electro-organic and inorganic synthesis, electrochemical polymerization, molten salt electrolysis, electrochemical machining, metal finishing, reactor performance, failure mechanisms, corrosion control, materials selection and techniques. The third group deals with manufacturing techniques and surface treatment of materials for commercial reactors, commercial parts/materials, fastening, assembly and production of reactor parts and mathematical modelling of various reactor processes.

Aiming at the generation of hydrogen from water, electrochemical water splitting represents a promising clean technology for generating a renewable energy resource. The book reviews the fundamental aspects and describes recent research advances. Properties and characterization methods for various types of electrocatalysts are discussed, including noble metals, earth-abundant metals, metal-organic frameworks, carbon nanomaterials and polymers. Keywords: Electrochemical Water Splitting, Renewable Energy Resource, Electrocatalysts, Oxygen Evolution Reaction (OER), Noble Metal Catalysts, Earth-Abundant Metal Catalysts, MOF Catalysts, Carbon-based Nanocatalysts, Polymer Catalysts, Transition Metal-based Electrocatalysts, Fe-based Electrocatalysts, Co-based Electrocatalysts, Ni-based Electrocatalysts, Metal Free Catalysts, Transition-Metal Chalcogenides, Prussian Blue Analogues.