Author: Hongsun KimPublisher:
ISBN:
Category :
Languages : en
Pages : 262
Book Description
Characterization of Pt-based Heterogeneous Electrocatalysts and Catalysis Modeling
Author: Hongsun KimCharacterization of Platinum-Based Heterogeneous Electrocatalysts and Catalysis Modeling
Author: Heterogeneous Catalysts
Author: Wey Yang TeohPublisher: John Wiley & Sons
ISBN: 3527813586
Category : Technology & Engineering
Languages : en
Pages : 768
Book Description
Presents state-of-the-art knowledge of heterogeneous catalysts including new applications in energy and environmental fields This book focuses on emerging techniques in heterogeneous catalysis, from new methodology for catalysts design and synthesis, surface studies and operando spectroscopies, ab initio techniques, to critical catalytic systems as relevant to energy and the environment. It provides the vision of addressing the foreseeable knowledge gap unfilled by classical knowledge in the field. Heterogeneous Catalysts: Advanced Design, Characterization and Applications begins with an overview on the evolution in catalysts synthesis and introduces readers to facets engineering on catalysts; electrochemical synthesis of nanostructured catalytic thin films; and bandgap engineering of semiconductor photocatalysts. Next, it examines how we are gaining a more precise understanding of catalytic events and materials under working conditions. It covers bridging pressure gap in surface catalytic studies; tomography in catalysts design; and resolving catalyst performance at nanoscale via fluorescence microscopy. Quantum approaches to predicting molecular reactions on catalytic surfaces follows that, along with chapters on Density Functional Theory in heterogeneous catalysis; first principles simulation of electrified interfaces in electrochemistry; and high-throughput computational design of novel catalytic materials. The book also discusses embracing the energy and environmental challenges of the 21st century through heterogeneous catalysis and much more. Presents recent developments in heterogeneous catalysis with emphasis on new fundamentals and emerging techniques Offers a comprehensive look at the important aspects of heterogeneous catalysis Provides an applications-oriented, bottoms-up approach to a high-interest subject that plays a vital role in industry and is widely applied in areas related to energy and environment Heterogeneous Catalysts: Advanced Design, Characterization and Applications is an important book for catalytic chemists, materials scientists, surface chemists, physical chemists, inorganic chemists, chemical engineers, and other professionals working in the chemical industry.
Characterization of Heterogeneous Catalysts
Author: Francis DelannayPublisher: Marcel Dekker
ISBN:
Category : Science
Languages : en
Pages : 432
Book Description
Catalysis and Electrocatalysis at Nanoparticle Surfaces
Author: Andrzej WieckowskiPublisher: CRC Press
ISBN: 0203912713
Category : Science
Languages : en
Pages : 970
Book Description
Illustrating developments in electrochemical nanotechnology, heterogeneous catalysis, surface science and theoretical modelling, this reference describes the manipulation, characterization, control, and application of nanoparticles for enhanced catalytic activity and selectivity. It also offers experimental and synthetic strategies in nanoscale surface science. This standard-setting work clariefies several practical methods used to control the size, shape, crystal structure, and composition of nanoparticles; simulate metal-support interactions; predict nanoparticle behavior; enhance catalytic rates in gas phases; and examine catalytic functions on wet and dry surfaces.
Construction and Reactivity of Pt-Based Bi-component Catalytic Systems
Author: Rentao MuPublisher: Springer
ISBN: 3662552442
Category : Science
Languages : en
Pages : 99
Book Description
In this thesis, the author outlines the construction of active structure and modulation of catalytic reactivity of Pt-based bi-component catalysts, from the model systems to real supported catalysts. The thesis investigates the promotion effect of the second components on catalytic performance of Pt catalysts, and presents the reversible generation of the “sandwich-like” structure of Pt-Ni catalysts, containing both surface NiO1-X and subsurface Ni by alternating redox treatments at medium temperature. With the aid of single layer graphene, the dynamic process of chemical reactions occurring on the Pt(111) surface can be visualized using in-situ LEEM and DUV-PEEM techniques, the results of which are included here. The author reveals that the graphene layer exhibits a strong confinement effect on the chemistry of molecules underneath and the intercalated CO can desorb from the Pt surface around room temperature and in UHV, which may promote the CO oxidation confined under graphene.
Supported Metal Single Atom Catalysis
Author: Philippe SerpPublisher: John Wiley & Sons
ISBN: 3527830170
Category : Technology & Engineering
Languages : en
Pages : 912
Book Description
b”Supported Metal Single Atom CatalysisCovers all key aspects of supported metal single atom catalysts, an invaluable resource for academic researchers and industry professionals alike Single atom catalysis is one of the most innovative and dynamic research areas in catalysis science. Supported metal catalysts are used extensively across the chemical industry, ranging from fine and bulk chemical production to petrochemicals. Single atom catalysts (SACs) combine the advantages of both homogeneous and heterogeneous catalysts such as catalyst stability, activity, and high dispersion of the active phase. Supported Metal Single Atom Catalysis provides an authoritative and up-to-date overview of the emerging field, covering the synthesis, preparation, characterization, modeling, and applications of SACs. This comprehensive volume introduces the basic principles of single atom catalysis, describes metal oxide and carbon support materials for SAC preparation, presents characterization techniques and theoretical calculations, and discusses SACs in areas including selective hydrogenation, oxidation reactions, activation of small molecules, C-C bond formation, and biomedical applications. Highlights the activity, selectivity, and stability advantages of supported metal SACs compared to other heterogeneous catalysts Covers applications of SACs in thermal catalysis, electrocatalysis, and photocatalysis Includes chapters on single atom alloys and supported double and triple metal atom catalysts Discusses the prospects, challenges, and potential industrial applications of SACs Supported Metal Single Atom Catalysis is an indispensable reference for all those working in the fields of catalysis, solid-state chemistry, materials science, and spectroscopy, including catalytic chemists, organic chemists, electrochemists, theoretical chemists, and industrial chemists.
Realistic Modeling of the Catalytic Heterogeneous Interface
Author: Mai-Anh HaPublisher:
ISBN:
Category :
Languages : en
Pages : 261
Book Description
At the catalytic interface, catalysts are represented by an ensemble of cluster isomers or surfaces, each of which may contribute to the system's stability, activity, selectivity, and resistance to sintering or poisons by reaction byproducts. I use ab-initio methods in conjunction with statistical-mechanical arguments to predict physico-chemical properties and guide development of premiering catalysts. Specifically, I utilize the work-horse of computation, density functional theory (DFT) calculations, to characterize systems of interest. Statistical-mechanical arguments such as Boltzmann-populations allow us to understand the role of relevant cluster isomers, surfaces, and reagents within the high temperature regime of real catalysis. My theoretical work applies this ensemble perspective of heterogeneous catalysis to diverse systems, from supported subnano-clusters to surfaces such as defective anatase for photocatalysis and Pt-Ni for fuel cells. Supported metal clusters often display non-monotonic behavior in which a cluster of a specific n size may be especially active. My theoretical work at UCLA explores the high activity and tunability of supported clusters by investigating the system as an ensemble. Three of my four first author papers represent fundamental, surface science work into tuning supported clusters. In particular, the well-known Pt-Pd resistance to sintering i.e. agglomeration of the clusters to bulk inertness was explained successfully through this ensemble consideration. 1:1 ratios of Pt:Pd featured more accessible isomers than their pure and mixed counterparts, resulting in an entropic contribution to chemical stability. In collaboration with experiment, we identified the highly active Pt7 for ethylene dehydrogenation, each negatively charged cluster able to adsorb and activate a maximum of 3 ethylenes. Pt7's high activity over that of a similar cluster size, Pt8, resulted from Pt7's fluxionality, the ensemble is able to access isomer geometries with more exposed Pt sites. Selective de(hydrogenation) forms the basis for fossil fuel refinery through cracking of hydrocarbons3 and, due to its endothermic nature, can act as a self-cooling mechanism for jet engines. It also represents a tractable process for testing the tunability of cluster size and dopant effects. Successive de(hydrogenation) often results in deactivation as catalyst sites are blocked by carbon (coking). We therefore tempered that high activity and predilection towards coke formation by doping Pt7 with the electropositive boron, which sustained activity during successive reaction cycles by adsorbing and activating ~1 ethylene. The ensemble perspective may also be extended to surfaces by accounting for non-equivalent defect sites, the local minima of reaction reagents and their subsequent products, or the distribution of facets present at the interface. The anatase surface remains ubiquitous in the field of catalysis for its unique photoactivity and reactivity, specifically, for CO2 reduction and water-splitting. CO2 reduction is an intermediate step towards the formation of organic products such as methanol and water-splitting for hydrogen evolution remains key to renewable energy. Both theory and experiment have cited surface defects such as oxygen vacancies to be a major contributing factor in anatase's catalytic activity. I examined 9 non-equivalent oxygen vacancy sites under varying levels of theory and characterized a new surface oxygen vacancy minimum, whose electrons localized at unique Ti sites as compared to previous studies. This has important ramifications on the catalysis of reaction intermediates due to their interaction with surface oxygen vacancies. For example, the co-adsorption of CO2 and H2O at an oxygen vacancy results in spontaneous splitting of water (global minimum) and the formation of other organic species such as formic acid (local minima). Tilocca, et. al. estimated the barrier to be circa 0.1 eV and this barrier is eliminated in the presence of CO2 and an oxygen vacancy. In addition to a comprehensive study of defective anatase, I also characterized the interface of Pt-Ni nanowires in depth by considering varying lattice constants, facets, and Pt-skins on a sub-alloy of Pt-Ni. The Pt-Ni nanowires expressed high catalytic activity and durability for the oxygen reduction reaction (ORR). ORR remains the limiting factor in fuel cells due to cost (requiring high Pt-loadings) and kinetics (occurring at a rate of six orders of magnitude slower than the hydrogen oxidation reaction). By considering the interface in such complexity, I converged upon the same facet distribution and lattice constant as experiment's high performer of (100) ~ (111) > (110) at a compressed lattice constant of ~ 3.7 i . This trend in stability observed by theory explained in part the durability of this high performer. Thus, the system-specific investigations for catalysis presented in this dissertation show that I have successfully applied ab-initio methods in conjunction with statistical-mechanical arguments to understand the role of heterogeneity (e.g., cluster isomers, defect sites, facets) in determining catalytic properties. Our in silico predictions of stability and activity have complemented and informed or even prompted the development of novel catalysts from supported clusters to extended surfaces.
PEM Fuel Cell Electrocatalysts and Catalyst Layers
Author: Jiujun ZhangPublisher: Springer Science & Business Media
ISBN: 1848009364
Category : Technology & Engineering
Languages : en
Pages : 1147
Book Description
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.
Surface Characterization of Heterogeneous Catalysts Using Low Energy Ion Scattering Spectroscopy Combined with Electrochemistry
Author: Stephanus AxnandaPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Fundamental studies of heterogeneous catalysis were performed and presented in this dissertation to gain a better understanding of heterogeneous catalytic reactions at a molecular level. Surface science techniques were employed in achieving the goal. Low energy ion scattering spectroscopy (LEISS) is the main surface science technique which will be used in all the studies discussed throughout this dissertation. The main objectives of LEISS measurements are to: 1) obtain the information of surface composition of heterogeneous catalysts from the topmost layer; 2) observe the effects of reaction conditions on the surface composition of heterogeneous catalysts. The surface composition and morphology of Au-Pd clusters bimetallic model catalysts supported on SiO2 were characterized using LEISS, infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). It is observed that relative to the bulk, the surface of the clusters is enriched in Au. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts. Fundamental studies of heterogeneous catalysis were performed and presented in this dissertation to gain a better understanding of heterogeneous catalytic reactions at a molecular level. Surface science techniques were employed in achieving the goal. Low energy ion scattering spectroscopy (LEISS) is the main surface science technique which will be used in all the studies discussed throughout this dissertation. The main objectives of LEISS measurements are to: 1) obtain the information of surface composition of heterogeneous catalysts from the topmost layer; 2) observe the effects of reaction conditions on the surface composition of heterogeneous catalysts. The surface composition and morphology of Au-Pd clusters bimetallic model catalysts supported on SiO2 were characterized using LEISS, infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). It is observed that relative to the bulk, the surface of the clusters is enriched in Au. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.