Download or read book Synthesis of Uncapped Noble Metal Nanoparticles by Laser Reduction in Liquid written by Katharine Tibbetts and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Uncapped, or u201cnakedu201d metal nanoparticles have pure metal/oxide surfaces that are amenable to subsequent conjugation with biocompatible ligands and provide active surface sites for catalysis. This presentation will highlight my groupu2019s recent work on the synthesis of uncapped u201cnakedu201d Au, Pd, and Ag nanoparticles by femtosecond laser-induced reduction of salt precursors in aqueous solution. Focusing femtosecond laser pulses into a condensed medium produces a dense plasma containing electrons and radicals that can reduce metal ions to neutral metal atoms, which coalesce into nanoparticles. For Au, Pd, and Ag salts, distinct reduction mechanisms operate that depend on one or more of the following reactive species: hydrated electrons, hydroxyl radicals, hydrogen peroxide, and hydrogen molecules. Following a discussion of these mechanisms, I will present chemical strategies for controlling the plasma composition by changing the solution pH and adding radical scavengers. Each metal requires distinct solution chemistry to effectively manipulate the nanoparticle sizes and morphologies. For instance, adding hydroxyl radical scavengers during reduction of KAuCl4 enables control over Au nanoparticle size distributions, while the choice of Pd salt determines the morphologies of Pd nanoparticles.

Download or read book Metal oxide Nanostructures Fabricated from Reactive Laser Ablation in Liquid written by Mallory G. John and published by . This book was released on 2020 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of metal-oxide nanostructures is a growing area due to their applications in diverse fields spanning energy conversion and storage, chemical manufacturing, and en- vironmental technology. This interest in catalytically active nanomaterials has prompted the synthesis and investigation of highly functionalized nanoparticles (NPs), including core- shell, silicate-stabilized, and bi- and multi-metallic nanocomposites. While wet-chemical synthesis methods of metal-oxide nanostructures have led to several morphologies, compositions, and shapes, these syntheses often require high temperatures, toxic solvents or reducing agents, and long reaction times. Laser synthesis and processing of colloids (LSPC) encompasses both 'top down' and 'bottom up' approaches to synthesize metal-oxide nanostructures. Pulsed laser ablation in liquid (PLAL) involves focusing laser pulses onto a solid target immersed in a liquid in which target atoms coalesce to form nanostructured materials once ejected into solution. Laser reduction in liquid (LRL) is a second laser-assisted approach to synthesizing nanomaterials, where photochemical reduction of metal salts is achieved by focusing the laser beam into solution. Both PLAL and LRL are able to generate metal and semiconductor NPs at room temperature in aqueous solutions without added surfactants or stabilizers, giving them an advantage over conventional wet-chemical methods. Recently, these two approaches have been combined into a single step- referred to as reactive laser ablation in liquid (RLAL), in which laser ablation of a solid target is carried out in a metal salt solution. This work goes through the synthesis and characterization of femtosecond-RLAL (fs-RLAL)-generated silica-metal nanostructures, and discusses the relationship between the precursor solution composition, the product morphology, and the catalytic activity toward a model para-nitrophenol (PNP) reduction reaction. First, silica-Au NPs were synthesized, exhibiting two populations of product nanoparticles which resulted from reaction dynamics occurring on two distinct timescales. Next, silica-Cu NPs were synthesized under different pH conditions, yielding pH-dependent product morphology. The different morphologies resulted from the surface charge of ablated silica species, which repelled the Cu2 ions in solution at low pH yielding core/shell morphology, and attracted the Cu2+ ions at high pH, forming well-dispersed

Download or read book Synthesis of Silver Nanoparticles Using Laser Ablation An Update written by and published by Airlangga University Press. This book was released on 2024-06-10 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the transformative potential of silver nanoparticles in combating bacterial infections, with a particular focus on their role in preventing the growth of multispecies biofilms crucial to oral implant development and addressing peri-implantitis. The journey begins with exploring the historical use of silver in medicine, tracing back to the time of Hippocrates and its subsequent relegation due to concerns over side effects. As we delve into the contemporary era, nanotechnology takes center stage. The most cutting-edge technology available today, nanotechnology, has found applications across various domains, including medicine. Silver nanoparticles, in particular, have emerged as a promising tool in the fight against MDR bacteria. The book navigates through the intricate world of silver nanoparticles, examining their synthesis through innovative techniques like laser ablation. Laser Ablation in Liquids (LAL) is explored as a green and eco-friendly synthetic method, allowing for the creation of pure nanoparticles without using additional chemicals.

Download or read book Synthesis of Noble Metal Nanoparticles written by Mozhgan Bahadory and published by . This book was released on 2008 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reducing Agents in Colloidal Nanoparticle Synthesis written by Stefanos Mourdikoudis and published by Royal Society of Chemistry. This book was released on 2021-05-14 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoparticles can be synthesised via a number of methods, including chemical vapor deposition, ball milling, laser ablation, thermal decomposition and chemical reduction. Chemical reduction is usually preferred, due to its ease and cost-effectiveness. There are several types of compound used as reducing agents in nanoparticle synthesis, and one recent development is the use of biological entities as environmentally friendly reductants. This book will highlight the role of reducing agents in the chemical synthesis of nanoparticle systems, presenting the main categories of reducing agents, which vary on reactivity, selectivity, availability and toxicity. It will provide a comprehensive presentation of both modern and more conventional types of reagents. Emphasis will be given on the presentation not only of the functionality, but also of all the different advantages and limitations of each kind of reducing agent. With contributions from global experts, this title will be appropriate for graduate students and researchers in nanochemistry, colloidal synthesis, inorganic chemistry, organometallic chemistry, chemical engineering, physical chemistry, materials science, biology and physics.

Download or read book Laser synthesized Bioconjugated Noble Metal Nanoparticles Rational Design and Efficacy Against Pathological Protein Aggregation written by Carmen Streich and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterisation of Noble Metal Nanoparticles in Reverse Microemulsion written by Weide Chen and published by . This book was released on 1996 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid written by Valery A. Svetlichnyi and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic mechanisms of pulsed laser ablation in liquids (PLAL) as a method for the synthesis of nanoparticles (NPs) were considered. Physical and chemical processes occurring during the PLAL that determine the formation, composition and structure of the nanoparticles obtained are described. The influence of the composition and properties of the target material, the solvent and the characteristics of the laser irradiation on the efficiency of the synthesis of nanoparticles is discussed. Separately, an influence of the absorption and scattering (including nonlinear) of laser radiation in the dispersion of nanoparticles on the primary synthetic processes and secondary transformations inside the colloidal solution is examined. The specificity of the characterization of the colloidal solutions of oxide particles produced by PLAL is highlighted. The most promising practical applications of nanomaterials obtained are identified and the examples of their successful use in catalytic research and biomedicine are provided.

Download or read book Synthesis and Study of Noble Metal Nanoparticles written by Niti Garg and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Green Synthesis and Gold Alloying of Silver Molecular Nanoparticles written by Badri Bhattarai and published by . This book was released on 2018 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noble metal nanoparticles have been extensively studied for use in applications in a diverse range of fields such as optoelectronics, catalysis, sensing, medicine, etc. due to their unique properties that arise as a result of their dimensions. Metal nanoparticles of size less than 3 nm exhibit molecular properties, unlike larger nanoparticles. These molecular nanoparticles are excellent model systems to study the chemistry of nanomaterials at the molecular level as their molecular formulae, crystal structure, chemical composition, electronic structures etc. can be experimentally measured and theoretically calculated. In addition, knowledge of their thermodynamic stability and mechanisms of formation can be leveraged in developing green synthetic routes in order to produce safer products that widen the range of applications, and to develop safer processes that increase manufacturability and decrease waste. Even though nanoparticle research is more focused on the end product and their properties, rather than the process, we have taken a different route of dismantling the M4Ag44(p-MBA)30 nanoparticle synthesis and developing a green route with significantly improved efficiency and an 89% yield. The need of solvent, which contributed to 98% of the waste, was kept to a minimum by using a stoichiometric silver-thiolate polymer as a precursor to intimately mix the metal atoms and ligands, and by forming a paste using a small amount of liquid to promote mass transport. The process mass intensity (PMI), a green metric defined by material input over product output, was decreased by almost 18-fold compared to the solution-phase synthesis. Some toxic chemicals were also removed or replaced throughout the process. This method is very effective for thermodynamically favorable products, and should be useful for other systems too. Alloying of metal nanoparticles is advantageous to achieve new properties. For example, gold-silver bimetallic NPs can be more stable than silver NPs and have better optical properties than gold NPs. Here we have studied the alloying process in M4AuxAg44-x(p-MBA)30 alloy nanoparticles, where 0 = x = 12, and M is a countercation. Two methods were used to synthesize M4AuxAg44-x(p-MBA)30 alloy nanoparticles: (i) co-reduction of gold-thiolate and silver-thiolate with alkali borohydride, and (ii) galvanic-exchange reaction between gold-thiolate and M4Ag44(p-MBA)30 nanoparticles in order to substitute silver with gold. The major findings were: (i) the number of gold atoms incorporated in the alloy was always less than the gold input, (ii) only up to twelve gold atoms were incorporated, (iii) gold prefers to stay at the innermost core energetically in alloy nanoparticles, as shown by the x-ray crystal structure of M4Au12Ag32(p-MBA)30 alloy nanoparticles, (iv) gold atom distributions were generally Gaussian, and (v) addition of gold in silver nanoparticles to create alloys increases the stability against oxidation.

Download or read book Synthesis and Stabilization of Noble Metal Nanoparticles Applications written by Bharat A. Makwana and published by . This book was released on 2016-10-03 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Growth of Anisotropic Noble Metal Nanoparticles written by Matthew Gara and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Measurement of Noble Metal Nanoparticles with Well defined Shapes by Electrochemical and Electroless Approaches written by Sean P. McDarby and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Morphology Control of Noble Metal Nanoparticle Catalysts Using Strategic Organic Capping Agents in Colloidal Phase Synthesis written by Kayla Mae Roeser and published by . This book was released on 2014 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noble metals are the most sought after elements for catalysis because of their versatility, activity, and recyclability for a variety of applications; however they are limited as a resource and expensive. Noble metal nanoparticles offer a solution for use in catalysis because their high surface area to volume ratio maximizes their available surface sites while minimizing the amount of metal used. Additionally, particularly exposed facets of nanoparticles can increase surface energies for superior catalytic activity and induce novel electronic/physical properties. In the first chapter of my thesis, I synthesized palladium, platinum, and semiconductor titania nanoparticles through a biomimetic approach by using peptides to preferentially bind to and expose particular crystal facets of nanoparticles. Using a combinatorial approach called biopanning to find highly selective surface energy modifiers for particular facets of materials gave insight to unique binding motifs for materials as well as induced morphology controlled nanoparticles at ambient conditions. There are limitless combinations of solvents, capping agents, and inorganic precursors for inorganic nanoparticle synthesis. Understanding these systems in terms of more global trends would circumvent the current colossal approach of empirically screening systems. To do this, considering the inorganic-organic interfacial relationship is key. In the second chapter, I report unique aryl small molecules which preferentially bind to palladium surfaces through electrostatic potentials and epitaxial binding in nanoparticle synthesis. These results offer an understanding to the dynamic binding relationship between capping agents and nanoparticle surfaces. Lastly, I report on the synthesis of gold-palladium nanoparticles and their activity for the benzyl alcohol oxidation reaction. It was found that the (100) facets of gold-palladium were more catalytically active than the (111) surface. Details of the nanoparticle shape, size, and activity add to the understanding how this material behaves at the atomic level and will help to impact future advances in this field of catalysis. The syntheses described here are important because they are environmentally friendly, they offer information about the binding mechanisms at the organic-inorganic interface of the systems, and give insight to catalytic behavior. All of this work is necessary to further exploit nanoparticle synthesis, assembly and provide the precise engineering of nanostructured materials.

Download or read book Biomimetic Synthesis of Noble Metal Nanoparticles and Their Applications as Electro catalysts in Fuel Cells written by Yujing Li and published by . This book was released on 2012 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SIZE CONTROLLED SYNTHESIS OF TRANSITION METAL NANOPARTICLES THROUGH CHEMICAL AND PHOTO CHEMICAL ROUTES written by Behzad Tangeysh and published by . This book was released on 2015 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: The central objective of this work is developing convenient general procedures for controlling the formation and stabilization of nanoscale transition metal particles. Contemporary interest in developing alternative synthetic approaches for producing nanoparticles arises in large part from expanding applications of the nanomaterials in areas such as catalysis, electronics and medicine. This research focuses on advancing the existing nanoparticle synthetic routes by using a new class of polymer colloid materials as a chemical approach, and the laser irradiation of metal salt solution as a photo-chemical method to attain size and shape selectivity. Controlled synthesis of small metal nanoparticles with sizes ranging from 1 to 5nm is still a continuing challenge in nanomaterial synthesis. This research utilizes a new class of polymer colloid materials as nano-reactors and protective agents for controlling the formation of small transition metal nanoparticles. The polymer colloid particles were formed from cross-linking of dinegatively charged metal precursors with partially protonated poly dimethylaminoethylmethacrylate (PDMAEMA). Incorporation of [PtCl6]2- species into the colloidal particles prior to the chemical reduction was effectively employed as a new strategy for synthesis of unusually small platinum nanoparticles with narrow size distributions (1.12 ± 0.25nm). To explore the generality of this approach, in a series of proof-of-concept studies, this method was successfully employed for the synthesis of small palladium (1.4 ±0.2nm) and copper nanoparticles (1.5 ±0.6nm). The polymer colloid materials developed in this research are pH responsive, and are designed to self-assemble and/or disassemble by varying the levels of protonation of the polymer chains. This unique feature was used to tune the size of palladium nanoparticles in a small range from 1nm to 5nm. The procedure presented in this work is a new convenient room temperature route for synthesis of small nanoparticles, and its application can be extended to the formation of other transition metals and alloy nanoparticles. This research also focuses on developing new photo-chemical routes for controlling the size and shape of the nanoparticles through high-intensity ultra-fast laser irradiation of metal salt solution. One of the core objectives of this work is to explore the special capabilities of shaped laser pulses in formation of metal nanoparticles through irradiation of the solutions by using simultaneous spatial and temporal focusing (SSTF). Femtosecond laser irradiation has not yet been widely applied for nanoparticle synthesis, and offers new regimes of energy deposition for synthesis of nanomaterials. Photo-reduction of aqueous [AuCl4]- solution to the gold nanoparticles (AuNPs) has been applied as a model process for optimizing the experimental procedures, and evaluating the potential of shaped laser pulses in the synthesis of AuNPs. Systematic manipulation of the laser parameters and experimental conditions provided effective strategies to control the size of Au nanoparticles in strong laser fields. Varying the concentration of polyethylene glycol (PEG45) as a surfactant effectively tuned the size of AuNPs from 3.9 ±0.7nm to 11.0 ±2.4nm, and significantly increased the rate of Au(III) reduction during irradiation. Comparative studies revealed the capability of shaped laser pulses in the generation of smaller and more uniform AuNPs (5.8 ±1.1nm) relative to the other conventional laser irradiation methods (7.2 ±2.9nm). Furthermore, a new laser-assisted approach has been developed for selective formation of triangular Au nanoplates in the absence of any surfactant molecule. This method relies on rapid energy deposition by using shaped, ultra-intense laser pulses to generate Au seeds in aqueous [AuCl4]- solution, and the slow post-irradiation reduction of un-reacted [AuCl4]- species by using H2O2 as a mild reducing agent. Variation of the laser irradiation-time was found as an effective strategy to tune the morphology of Au nanomaterials from nanospheres to triangular nanoplates. The surfactant-free Au nanoplates produced in this research can be readily functionalized with a variety of target molecules or surfactants for desirable applications such as biomedicine. The concept of rapid laser processing followed by in situ chemical reduction can be expanded as a general methodology for high-yield production of nanomaterials, and provides a series of new laser dependent parameters for controlling the nanoparticle formation.

Download or read book System and Method for Continuous Wave Low Power Laser Based Synthesis of Metal Nano Particles written by Sankaranarayana Iyer Sankararaman and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This disclosure relates to synthesis of metal nanoparticles (NPs). In particular, the invention relates to methods of synthesizing metal nanoparticles using Laser. The invention relates to Laser assisted synthesis of metal nanoparticles using continuous wave low laser power in a liquid medium. The system [100] for synthesis of metal nanoparticles, comprises of a laser source [101], a mechanical chopper [102], a lens [103], a target metal [104], a liquid medium [106] and a heat source [107]. Additionally the invention relates to laser assisted synthesis of metal nanoparticles with silver as the metal target and water as the liquid medium. The NPs produced are characterized by UV-Visible spectrophotometer, Field-emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Spectroscopy (EDS), and Transmission Electron Microscopy (TEM).Figure 1.