Surface Structure, Stability and Activity of Molybdenum Carbides Supported Transition Metal Catalysts PDF Download

Author: Fan Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: José Manuel Domínguez-Esquivel
Publisher: Springer Nature
ISBN: 3030259935
Category : Technology & Engineering
Languages : en
Pages : 223

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This book presents advances in computational methods, experimental synthesis, and advanced characterizations for novel catalytic materials. The authors show how catalytical materials can be used for various engineering oil & gas applications – mainly in low contaminants fuel production. All contributors, describe in detail novel experimental and theoretical techniques techniques and concepts for synthesis, evaluation and scaling catalytic materials and research advances in evaluation, extensive characterization and theoretical modeling using computer assisted methods and algorithms. Describes computational methods, experimental synthesis and advanced characterization for novel catalytic materials; Examines catalytic materials and corresponding engineering applications with a focus on low contaminant fuel production and derivatives; Covers the application of computer assisted quantum mechanical for fundamental understanding of electronic structure of molecular dimension catalytic materials.

Author: David William Flaherty
Publisher:
ISBN:
Category :
Languages : en
Pages : 638

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Catalysts can be significantly improved by modifying their structure or composition. Simple adaptations of the physical structure of a catalyst can give rise to changes in the chemical behavior, in part, due to alterations in the coordination of active sites. Modifications in the surface or bulk composition of a material have a profound impact on the chemistry that is promoted as a result of electronic and physical factors. Optimizing these qualities may enhance the catalyst's activity, selectivity or stability. In this dissertation, we explore the application of two distinct approaches for modifying the chemical properties of catalytically active materials. Through the use of a broad array of techniques we quantify changes in critical properties such as physical-crystallographic structure; morphology, surface area and porosity; as well as catalytic activity, selectivity and stability. First, reactive ballistic deposition of metal atoms within a low pressure gas provides a unique opportunity for synthesizing thin films of a wide variety of materials. The morphology, structure, and porosity of the resulting material can be tailored through control of the deposition angle and substrate temperature. By conducting deposition perpendicular to the surface, a film can be grown with a dense, conformal structure. On the other hand, deposition at oblique angles results in high surface area, porous films comprised of regular arrays of nanocolumnar structures. Furthermore, variations in the deposition angle allow for the inclusion of under-coordinated sites which change the chemical activity of the surface. Improvements in the activity, selectivity and stability of transition metal catalysts can be made by alloying the catalyst with a second element. The formation of molybdenum carbide decreases the strength of chemisorption on the surface, with respect to molybdenum, and improves selectivity for the dehydrogenation of formic acid. Platinum is active for the water-gas shift reaction. However, this catalyst cannot operate at low temperatures due to CO poisoning and is susceptible to deactivation due to accumulation of carbonaceous deposits. The formation of a platinum-copper near-surface alloy dramatically modifies the interactions of the surface with CO, H2O and H2 which can enhance the performance of this catalyst for the water-gas shift reaction.

Author: Justin S J Hargreaves
Publisher: Royal Society of Chemistry
ISBN: 178262919X
Category : Science
Languages : en
Pages : 210

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Many important industrial chemical processes rely heavily on catalysis and so researchers are always on the lookout for alternative catalytic materials that may improve existing processes or lead to new ones. Families of alternative catalytic materials currently being investigated include the carbides, nitrides and phosphides as well as amorphous boron catalysts. The addition of carbon, nitrogen or phosphorous to transition metals and the creation of boron-transition metal alloys leads to catalytic materials that have interesting properties, with applications in a range of different reactions, including electrocatalysis. This book provides a comprehensive account of the preparation, characterisation and application of these catalytic materials. It is an important reference for researchers and industrialists working in heterogeneous catalysis and materials chemistry.

Author: Gregory Martin Dolce
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 360

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Author: Louis Toth
Publisher: Elsevier
ISBN: 032315722X
Category : Technology & Engineering
Languages : en
Pages : 296

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Refractory Materials, Volume 7: Transition Metal Carbides and Nitrides discusses the developments in transition metal carbide and nitride research. This volume is organized into nine chapters that emphasize the mechanical and superconducting properties of these compounds. The introductory chapters deal with the general properties, preparation techniques, characterization, crystal chemistry, phase relationships, and thermodynamics of transition metal carbides and nitrides. The following chapter highlights the mechanical properties of these compounds, such as elastic and plastic deformation, fracture, strengthening mechanisms, and hardness. The discussion then shifts to specific electrical and magnetic properties, including electrical resistivity, Hall coefficient, and magnetic susceptibility. A separate chapter is devoted to carbides and nitrides as superconductors. The concluding chapters explore certain theories that explain the mechanisms of band structure and bonding in carbides and nitrides. This volume is of great value to research workers in metallurgy, ceramics, physics, chemistry, and related fields, as well as to advanced students investigating problems concerning high temperature materials or interstitial compounds.

Author: David Charles Lamont
Publisher:
ISBN:
Category : Catalytic reforming
Languages : en
Pages :

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Author: Gurbinder Kaur
Publisher: Elsevier
ISBN: 0128237090
Category : Science
Languages : en
Pages : 584

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PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides a comprehensive introduction to the principles of PEM fuel cell, their working condition and application, and the latest breakthroughs and challenges for fuel cell technology. Each chapter follows a systematic and consistent structure with clear illustrations and diagrams for easy understanding. The opening chapters address the basics of PEM technology; stacking and membrane electrode assembly for PEM, degradation mechanisms of electrocatalysts, platinum dissolution and redeposition, carbon-support corrosion, bipolar plates and carbon nanotubes for the PEM, and gas diffusion layers. Thermodynamics, operating conditions, and electrochemistry address fuel cell efficiency and the fundamental workings of the PEM. Instruments and techniques for testing and diagnosis are then presented alongside practical tests. Dedicated chapters explain how to use MATLAB and COMSOL to conduct simulation and modeling of catalysts, gas diffusion layers, assembly, and membrane. Degradation and failure modes are discussed in detail, providing strategies and protocols for mitigation. High-temperature PEMs are also examined, as are the fundamentals of EIS. Critically, the environmental impact and life cycle of the production and storage of hydrogen are addressed, as are the risk and durability issues of PEMFC technology. Dedicated chapters are presented on the economics and commercialization of PEMFCs, including discussion of installation costs, initial capital costs, and the regulatory frameworks; apart from this, there is a separate chapter on their application to the automotive industry. Finally, future challenges and applications are considered. PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides an in-depth and comprehensive reference on every aspect of PEM fuel cells fundamentals, ideal for researchers, graduates, and students. - Presents the fundamentals of PEM fuel cell technology, electrolytes, membranes, modeling, conductivity, recent trends, and future applications - Addresses commercialization, public policy, and the environmental impacts of PEMFC in dedicated chapters - Presents state-of-the-art PEMFC research alongside the underlying concepts

Author: Babak Anasori
Publisher: Springer Nature
ISBN: 3030190269
Category : Technology & Engineering
Languages : en
Pages : 534

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This book describes the rapidly expanding field of two-dimensional (2D) transition metal carbides and nitrides (MXenes). It covers fundamental knowledge on synthesis, structure, and properties of these new materials, and a description of their processing, scale-up and emerging applications. The ways in which the quickly expanding family of MXenes can outperform other novel nanomaterials in a variety of applications, spanning from energy storage and conversion to electronics; from water science to transportation; and in defense and medical applications, are discussed in detail.

Author: Oscar Gerardo Marin-Flores
Publisher:
ISBN:
Category :
Languages : en
Pages :

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