Methods for Modifying the Physical and Catalytic Properties of Surfaces

Methods for Modifying the Physical and Catalytic Properties of Surfaces PDF Author: David William Flaherty
Publisher:
ISBN:
Category :
Languages : en
Pages : 638

Get Book Here

Book Description
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.

Methods for Modifying the Physical and Catalytic Properties of Surfaces

Methods for Modifying the Physical and Catalytic Properties of Surfaces PDF Author: David William Flaherty
Publisher:
ISBN:
Category :
Languages : en
Pages : 638

Get Book Here

Book Description
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.

Surface Treatments for Biological, Chemical and Physical Applications

Surface Treatments for Biological, Chemical and Physical Applications PDF Author: Mehmet Gürsoy
Publisher: John Wiley & Sons
ISBN: 3527698809
Category : Technology & Engineering
Languages : en
Pages : 314

Get Book Here

Book Description
A step-by-step guide to the topic with a mix of theory and practice in the fields of biology, chemistry and physics. Straightforward and well-structured, the first chapter introduces fundamental aspects of surface treatments, after which examples from nature are given. Subsequent chapters discuss various methods to surface modification, including chemical and physical approaches, followed by the characterization of the functionalized surfaces. Applications discussed include the lotus effect, diffusion barriers, enzyme immobilization and catalysis. Finally, the book concludes with a look at future technology advances. Throughout the text, tutorials and case studies are used for training purposes to grant a deeper understanding of the topic, resulting in an essential reference for students as well as for experienced engineers in R&D.

Selectivity in Catalysis

Selectivity in Catalysis PDF Author: Mark E. Davis
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 432

Get Book Here

Book Description
Discusses recent research and provides tutorial chapters on enhancing selectivity in catalysis through stereoselectivity, reaction pathway control, shape selectivity, and alloys and clusters. Presents an interdisciplinary approach to increasing selectivity in homogeneous and heterogeneous catalysis research. Includes an overview chapter that discusses the current state of the field and offers a perspective on future directions.

Tailoring Surfaces

Tailoring Surfaces PDF Author: Nicholas D. Spencer
Publisher: World Scientific
ISBN: 9814289426
Category : Technology & Engineering
Languages : en
Pages : 690

Get Book Here

Book Description
The focus of the book is the modification of surfaces to tailor them for a specific purpose. Using this method of surface modification, materials chosen for their bulk properties (tensile strength, temperature stability, density, price can be optimized for any particular application, which can lead to improved hardness, biological inertness or activity, corrosion resistance, low or high friction or adhesion, water repellency or wettability, or catalytic activity. The works of the author — many of his crucial papers are included — touches upon these surface properties and spans fields including catalysis, analytical surface science, self-assembled monolayers, tribology, biomaterials, superhydrophobicity and polymer coatings.

Surface Properties and Catalysis by Non-Metals

Surface Properties and Catalysis by Non-Metals PDF Author: J.P. Bonnelle
Publisher: Springer Science & Business Media
ISBN: 9400971605
Category : Science
Languages : en
Pages : 571

Get Book Here

Book Description
In the field of heterogeneous catalysis. it is convenient to distinguish. in a perfectly unjustified and over··simplified way. bet:leen metal catalysts. 2nd the other catalysts. The fj.J"st are easy to define : they are those in which a reduced metal is the active phase. It is thus easy to circumscribe. by exclusion, the other class namely the "non-metals". We have adopted this definition for the sake of our colleagues working on catalysis by metals, and to avoid a lengthy title like "sm' face pl"operties and catalysts by transi tion metal oxides. sulftdes, carbides, nitriles, etc. Defined in this manner, non-metal catalysts represented, in 1980, 84 wt. % of the industrial heterogeneous catalysts. To be more specific, this proportion corresponds to catalysts which, under the working conditions in the industrial ?lant. contain their catalytically active metallic elements in a non-reduced state. It should however be recalled that most metal catalysts are supported on oxides, which, often, repl'esent over 90% (sometimes 99.4% in the case of the platinum reforming catalysts) of the total weight.

Surface Treatments for Biological, Chemical and Physical Applications

Surface Treatments for Biological, Chemical and Physical Applications PDF Author: Mehmet Gürsoy
Publisher: John Wiley & Sons
ISBN: 3527340831
Category : Technology & Engineering
Languages : en
Pages : 312

Get Book Here

Book Description
A step-by-step guide to the topic with a mix of theory and practice in the fields of biology, chemistry and physics. Straightforward and well-structured, the first chapter introduces fundamental aspects of surface treatments, after which examples from nature are given. Subsequent chapters discuss various methods to surface modification, including chemical and physical approaches, followed by the characterization of the functionalized surfaces. Applications discussed include the lotus effect, diffusion barriers, enzyme immobilization and catalysis. Finally, the book concludes with a look at future technology advances. Throughout the text, tutorials and case studies are used for training purposes to grant a deeper understanding of the topic, resulting in an essential reference for students as well as for experienced engineers in R&D.

Surface Modified Nanomaterials for Applications in Catalysis

Surface Modified Nanomaterials for Applications in Catalysis PDF Author: Manoj B. Gawande
Publisher: Elsevier
ISBN: 0128236027
Category : Science
Languages : en
Pages : 392

Get Book Here

Book Description
Surface Modified Nanomaterials for Applications in Catalysis: Fundamentals, Methods and Applications provides an overview of the different state-of-the-art surface modification methods of nanomaterials and their commercial applications. The main objective of this book is to comprehensively cover the modification of nanomaterial and their fabrication, including different techniques and discussions of present and emerging commercial applications. The book addresses fundamental chemistry concepts as applied to the modification of nanomaterials for applications in energy, catalysis, water remediation, sensors, and more. Characterization and fabrication methodologies are reviewed, along with the challenges of up-scaling of processes for commercial applications. This book is suitable for academics and practitioners working in materials science, engineering, nanotechnology, green chemistry and chemical engineering. Provides an overview of the basic principles of surface modification of nanomaterials Reviews useful fabrication and characterization methodologies for key applications Addresses surface modified nanomaterials for applications in catalysis, energy, sensor, environment, and more

Surface Modification by Solid State Processing

Surface Modification by Solid State Processing PDF Author: Rosa M. Miranda
Publisher: Woodhead Publishing
ISBN: 9780081015308
Category : Science
Languages : en
Pages : 210

Get Book Here

Book Description
Surface Modification by Solid State Processing describes friction-based surfacing techniques for surface modification to improve resistance to corrosion and wear, also changing surface chemistry. Surface conditions are increasingly demanding in industrial applications and surface modification can reduce manufacturing and maintenance costs, leading to improved component performance, reliability and lifetime. Friction-based technologies are promising solid state processing technologies, particularly for light alloys, in the manufacturing of composite surface and functionally graded materials This title is divided into five chapters, and after an introduction the book covers friction surfacing; friction stir processing; surface reinforcements of light alloys; and characterization techniques based on eddy currents. Describes friction-based surfacing techniques for surface modification to improve resistance to corrosion and wear, and change surface chemistry Emphasizes industrial applications Describes existing and emerging techniques

Surface Modification of Biomaterials

Surface Modification of Biomaterials PDF Author: Rachel Williams
Publisher: Elsevier
ISBN: 0857090763
Category : Medical
Languages : en
Pages : 438

Get Book Here

Book Description
The surface modification of biomaterials plays a significant role in determining the outcome of biological-material interactions. With the appropriate modification a material's surface can be tailored to improve biocompatibility, adhesion and cell interactions. Consequently surface modification is vital in the development and design of new biomaterials and medical devices. Surface modification of biomaterials reviews both established surface modifications and those still in the early stages of research and discusses how they can be used to optimise biological interactions and enhance clinical performance.Part one begins with chapters looking at various types and techniques of surface modification including plasma polymerisation, covalent binding of poly (ethylene glycol) (PEG), heparinisation, peptide functionalisation and calcium phosphate deposition before going on to examine metal surface oxidation and biomaterial surface topography to control cellular response with particular reference to technologies, cell behaviour and biomedical applications. Part two studies the analytical techniques and applications of surface modification with chapters on analysing biomaterial surface chemistry, surface structure, morphology and topography before moving onto discuss modifying biomaterial surfaces to optimise interactions with blood, control infection, optimise interactions with soft tissues, repair and regenerate nerve cells, control stem cell growth and differentiation and to optimise interactions with bone.The distinguished editor and international team of contributors to Surface modification of biomaterials have produced a unique overview and detailed chapters on a range of surface modification techniques which will provide an excellent resource for biomaterials researchers and scientists and engineers concerned with improving the properties of biomaterials. It will also be beneficial for academics researching surface modification. - Reviews both established surface modifications and those still in the early stages of research and how they can be used to optimise biological interactions and enhance clinical performance - Studies analytical techniques and applications of surface modification with chapters assessing biomaterial surface chemistry, surface structure, morphology and topography - Discusses modifying biomaterial surfaces to optimise interactions with blood and soft tissues and also to repair and regenerate nerve cells and control infection

Polymer Surface Modification

Polymer Surface Modification PDF Author: K. L. Mittal
Publisher: BRILL
ISBN: 9004165908
Category : Technology & Engineering
Languages : en
Pages : 404

Get Book Here

Book Description
The topic of polymer surface modification is of tremendous contemporary interest because of its critical importance in many and varied technological applications where polymers are used. Currently there is brisk research activity in unraveling the mechanisms of surface modification and finding ways to prolong the life of surface treatment. Also there is acute interest and need to devise new, improved and economical means to modify polymer surfaces. This book is divided into three parts as follows: Part 1: Surface Modification Techniques; Part 2: Interfacial Aspects and Adhesion; Part 3: General Papers. The topics covered include: various techniques for surface modification including plasma (both vacuum and atmospheric pressure), ozone, photografting, UV photo-oxidation, laser, use of charged particles and others for a variety of polymers; longevity of surface treatment; hydrophobic recovery; fabrication of high-density polymer nano-dots; immobilization of organometallic catalysts on textile carrier materials; polymer membrane antifouling properties; electroless metallization of polymers; effects of surface modification on interfacial shear strength of composites, cord/rubber adhesion, adhesion of UV-curable coatings and attachment of hyperbranched polymers; plasma polymerization; block copolymers; application of plasma technology in decontamination of heat-sensitive polymer surfaces. In essence this book reflects the current state-of-the-knowledge in the arena and represents the work of many renowned scientists and technologists. It should be of interest to anyone with a desire or need to learn the latest R&D activity in this domain and the information contained here should be very valuable in deciding the optimum surface modification technique for his/her particular requirements.