Electrochemistry of Palladium with Emphasis on Size Dependent Electrochemistry of Water Soluble Palladium Nanoparticles

Electrochemistry of Palladium with Emphasis on Size Dependent Electrochemistry of Water Soluble Palladium Nanoparticles PDF Author: Ashok Kumar
Publisher:
ISBN:
Category : Electrochemistry
Languages : en
Pages : 115

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Book Description
Palladium metal in its various forms has been heavily studied for many catalytic, hydrogen storage and sensing applications and as an electrocatalyst in fuel cells. A short review on various applications of palladium and the mechanism of Pd nanoparticles synthesis will be discussed in chapter 1. Size dependent properties of various metal nanoparticles and a thermodynamic theory proposed by Plieth to predict size dependent redox properties of metal nanoparticles will also be discussed in chapter 1. To evaluate size dependent stability of metal nanoparticles using electrochemical techniques in aqueous media, a synthetic route was designed to produce water soluble Pd nanoparticles. Also, a purification technique was developed to obtain monodisperse metal nanoparticles to study size dependent stability using electrochemical methods. Chapter 2 will describe in detail the synthesis, characterization and size dependent anodic dissolution studies of water soluble palladium nanoparticles.The cost associated with using expensive metal catalysts can further decreased by using the underpotential deposition (UPD) technique, in which one metal is electrodeposited in monolayer or submonolayer form on a different metal substrate. Electrochemically, this process can be detected by the presence of a deposition peak positive to the bulk deposition potential in a cyclic voltammetry (CV) experiment. The difference between the bulk deposition potential and underpotential deposition peak (i.e. the UPD shift), which is a measure of the energetics of the monolayer deposition step, depends on the work function difference between the metal pairs. Chapter 3 will explore how metal nanoparticles of different sizes will change the energetics of the UPD phenomenon, using the UPD of Cu on palladium nanoparticles as an example. It will be shown that the UPD shift depends on the size of the nanoparticle substrate in a way that is understandable based on the Plieth model.High electrocatalytic activity of palladium towards ethanol oxidation in an alkaline medium makes it an ideal candidate for the anode electrocatalyst in direct ethanol based fuel cells (DEFCs). Chapter 4 will explore the poisoning of the catalytic activity of palladium in the presence of halide impurities, often used in synthesis of palladium nanoparticles as precursors or shape directing agents.

Electrochemistry of Palladium with Emphasis on Size Dependent Electrochemistry of Water Soluble Palladium Nanoparticles

Electrochemistry of Palladium with Emphasis on Size Dependent Electrochemistry of Water Soluble Palladium Nanoparticles PDF Author: Ashok Kumar
Publisher:
ISBN:
Category : Electrochemistry
Languages : en
Pages : 115

Get Book Here

Book Description
Palladium metal in its various forms has been heavily studied for many catalytic, hydrogen storage and sensing applications and as an electrocatalyst in fuel cells. A short review on various applications of palladium and the mechanism of Pd nanoparticles synthesis will be discussed in chapter 1. Size dependent properties of various metal nanoparticles and a thermodynamic theory proposed by Plieth to predict size dependent redox properties of metal nanoparticles will also be discussed in chapter 1. To evaluate size dependent stability of metal nanoparticles using electrochemical techniques in aqueous media, a synthetic route was designed to produce water soluble Pd nanoparticles. Also, a purification technique was developed to obtain monodisperse metal nanoparticles to study size dependent stability using electrochemical methods. Chapter 2 will describe in detail the synthesis, characterization and size dependent anodic dissolution studies of water soluble palladium nanoparticles.The cost associated with using expensive metal catalysts can further decreased by using the underpotential deposition (UPD) technique, in which one metal is electrodeposited in monolayer or submonolayer form on a different metal substrate. Electrochemically, this process can be detected by the presence of a deposition peak positive to the bulk deposition potential in a cyclic voltammetry (CV) experiment. The difference between the bulk deposition potential and underpotential deposition peak (i.e. the UPD shift), which is a measure of the energetics of the monolayer deposition step, depends on the work function difference between the metal pairs. Chapter 3 will explore how metal nanoparticles of different sizes will change the energetics of the UPD phenomenon, using the UPD of Cu on palladium nanoparticles as an example. It will be shown that the UPD shift depends on the size of the nanoparticle substrate in a way that is understandable based on the Plieth model.High electrocatalytic activity of palladium towards ethanol oxidation in an alkaline medium makes it an ideal candidate for the anode electrocatalyst in direct ethanol based fuel cells (DEFCs). Chapter 4 will explore the poisoning of the catalytic activity of palladium in the presence of halide impurities, often used in synthesis of palladium nanoparticles as precursors or shape directing agents.

Synthesis, Characterization and Electrochemical Hydrogen Insertion in ATP Capped Palladium Nanoparticles

Synthesis, Characterization and Electrochemical Hydrogen Insertion in ATP Capped Palladium Nanoparticles PDF Author: Timothy Lamb
Publisher:
ISBN:
Category : Adenosine triphosphate
Languages : en
Pages : 55

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Book Description
Water-soluble, adenosine triphosphate (ATP)-stabilized palladium nanoparticles have been synthesized by reduction of palladium salt in the presence of excess ATP. They have been characterized by electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and X-ray diffraction in order to determine particle size, shape, composition and crystal structure. The particles were then subsequently attached to a glassy carbon electrode (GCE) in order to explore their electrochemical properties with regard to hydrogen insertion in 1 M sodium hydroxide. The particles were found to be in the size range 2.5 to 4 nm with good size dispersion. The ATP capping ligand allowed the particles to be air-stable and re-dissolved without agglomeration. It was found that the NPs could be firmly attached to the working electrode via cycling the voltage repeatedly in a NP/phosphate solution. Further electrochemical experiments were conducted to investigate the adsorption and absorption of hydrogen in the NPs in 1 M sodium hydroxide. Results for cyclic voltammetry experiments were consistent with those for nanostructured and thin-film palladium in basic solution. Absorbed hydrogen content was analyzed as a function of potential. The maximum hydrogen:Pd ratio was found to be ~0.7, close the theoretical maximum value for beta phase palladium hydride.

Electrochemical Biosensors

Electrochemical Biosensors PDF Author: Serge Cosnier
Publisher: CRC Press
ISBN: 9814411477
Category : Science
Languages : en
Pages : 405

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Book Description
Since four decades, rapid detection and monitoring in clinical and food diagnostics and in environmental and biodefense have paved the way for the elaboration of electrochemical biosensors. Thanks to their adaptability, ease of use in relatively complex samples, and their portability, electrochemical biosensors now are one of the mainstays of analy

Self-Assembled Nanostructures

Self-Assembled Nanostructures PDF Author: Jin Zhang
Publisher: Springer Science & Business Media
ISBN: 0306479419
Category : Science
Languages : en
Pages : 327

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Book Description
Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.

Nanoanalytics

Nanoanalytics PDF Author: Sergei Shtykov
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110542013
Category : Science
Languages : en
Pages : 464

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Book Description
Nanoanalytics is a novel branch of analytical chemistry which explores applications of nanotechnologies in chemical analysis. This comprehensive publication gives an overview of the analytical techniques used to study nanoobjects and nanoparticles as well as the application of nanomaterials themselves in the development of new methods of analysis. The authors also address important metrology aspects and give future prospects of the area.

Nanostructured Palladium Electrochemistry

Nanostructured Palladium Electrochemistry PDF Author: Jan Marwan
Publisher: Springer Verlag
ISBN: 9781441982995
Category : Science
Languages : en
Pages : 300

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Book Description
This book examines in detail the electrochemical deposition, as well as the electrochemical features, of nanostructured palladium. It also sets out the perceived advantages associated with using the nanotechnological prerequisites to preparing these films.

Modern Aspects of Electrochemistry 42

Modern Aspects of Electrochemistry 42 PDF Author: Constantinos G. Vayenas
Publisher: Springer Science & Business Media
ISBN: 0387494898
Category : Science
Languages : en
Pages : 434

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Book Description
This volume analyzes and summarizes recent developments in several key interfacial electrochemical systems in the areas of fuel cell electrocatatalysis, electrosynthesis and electrodeposition. The six Chapters are written by internationally recognized experts in these areas and address both fundamental and practical aspects of several existing or emerging key electrochemical technologies. The Chapter by R. Adzic, N. Marinkovic and M. Vukmirovic provides a lucid and authoritative treatment of the electrochemistry and electrocatalysis of Ruthenium, a key element for the devel- ment of efficient electrodes for polymer electrolyte (PEM) fuel cells. Starting from fundamental surface science studies and interfacial considerations, this up-to-date review by some of the pioneers in this field, provides a deep insight in the complex catalytic-electrocatalytic phenomena occurring at the interfaces of PEM fuel cell electrodes and a comprehensive treatment of recent developments in this extremely important field. Several recent breakthroughs in the design of solid oxide fuel cell (SOFC) anodes and cathodes are described in the Chapter of H. Uchida and M. Watanabe. The authors, who have pioneered several of these developments, provide a lucid presentation d- cribing how careful fundamental investigations of interfacial electrocatalytic anode and cathode phenomena lead to novel electrode compositions and microstructures and to significant practical advances of SOFC anode and cathode stability and enhanced electrocatalysis.

Electrochemistry for Corrosion Fundamentals

Electrochemistry for Corrosion Fundamentals PDF Author: Toshiaki Ohtsuka
Publisher: Springer
ISBN: 9811068208
Category : Science
Languages : en
Pages : 123

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Book Description
This brief is concerned with the fundamentals of corrosion of metallic materials and electrochemistry for better understanding of corrosion phenomena. Corrosion is related to both the environment and material properties, induced by electrochemical reactions at the interface between metallic materials and the environment as in aqueous and gaseous phases. In order to understand corrosion phenomena, knowledge of electrochemistry is thus required, and to investigate the cause of corrosion damage, appropriate electrochemical experiments must be performed. Corrosion scientists should therefore possess knowledge of both electrochemistry and its related experimental techniques. In this book, corrosion phenomena are introduced from the electrochemical aspect. Electrochemical techniques for the study of corrosion are then described with other techniques that can be combined with electrochemistry. Because this brief is characterized as starting with the fundamentals of corrosion and electrochemistry, it is accessible to undergraduate students as well as to graduate students who are beginning corrosion research.

Controlling Activity of Ligand-capped Palladium Nanoparticle Catalysts

Controlling Activity of Ligand-capped Palladium Nanoparticle Catalysts PDF Author: May Maung
Publisher:
ISBN: 9781339826233
Category : Allyl alcohol
Languages : en
Pages : 48

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Book Description
Abstract: This thesis presents the systematic evaluation of palladium nanoparticles functionalized with well-defined small organic ligands that can provide a spatial control in the surrounding environment of nanoparticle catalyst surfaces. Various thiolate ligand-capped palladium nanoparticles are produced by using different S-alkylthiosufate ligand precursors in a two-phase system composed of toluene and water. These palladium nanoparticles are then characterized using transmission electron microscopy, thermogravimetric analysis, NMR, FT-IR, and UV-vis spectroscopy. The catalysis studies on alkanethiolate-capped palladium nanoparticles with different ligand structures (linear alkyl vs cyclohexyl vs phenyl) show that the chemical and structural composition of a monolayer surrounding the palladium nanoparticles greatly influences the overall activity and selectivity of nanoparticle catalysts for the hydrogenation, isomerization, and hydrogenolysis of allylic alcohols. Especially, the effect of non-covalent interactions between surface ligands and incoming substrates in the near-surface environment is observed. Furthermore, the catalytic properties of & ohgr;-carboxylate-functionalized alkanethiolate-capped palladium nanoparticles are studied for the biphasic reactions of hydrophobic allylic alcohols that are immiscible in aqueous solution. The systematic investigations on the influence of pH and substrate size are performed to check the utility of structurally stable and water-soluble palladium nanoparticles as new micellar catalysts.

Water-soluble Palladium Nanoparticles for the Oxidation of Terminal Alkenes

Water-soluble Palladium Nanoparticles for the Oxidation of Terminal Alkenes PDF Author: Edwin G. Avila (Graduate student)
Publisher:
ISBN:
Category : Alkenes
Languages : en
Pages : 52

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Book Description
Conventionally, the Tsuji-Wacker oxidation has been used to promote the Markovnikov oxidation of terminal alkenes to their respective ketones in the presence of dioxygen. Recently, the regioselective formation of the aldehyde via an anti-Markovnikov addition, which is of substantial importance to the chemistry community, has been demonstrated using a palladium/nitrite catalyst. Herein, we demonstrate the potential for the regioselective transformation of allylbenzene derivatives to their respective aldehydes under green catalytic conditions via the use of palladium nanoparticles in water. The same Pd nanoparticle catalysts were also investigated for the homocoupling of phenyl boronic acids under aerobic conditions. Catalysis results were examined using 1H NMR and/or GC-MS analyses.