Download or read book Synthesis of Palladium gold Alloy Nanoparticle Catalysts for the Reduction of Nitrite in Water written by Sarah Seraj and published by . This book was released on 2018 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogenation using palladium-based (Pd-based) catalysts has emerged as a promising treatment method for nitrate in drinking water. However, low catalytic activity and longevity can be a barrier to widespread adoption over conventional treatment methods. Controlling catalyst structure at the molecular scale is one approach to improving catalytic activity and longevity. Intermetallic palladium-gold nanoparticle (PdAu NP) alloy catalysts of varying composition were synthesized for nitrite reduction using a polyol reduction method and microwave-assisted heating. The average size of PdAu NPs was 4.1 ± 2.2 nm. Enhanced nitrite reduction has been previously observed for Pd combined with Au in a core-shell NP structure, but has not been studied for intermetallic PdAu alloy NPs. Moreover, the mechanism by which Au enhances Pd-catalyzed nitrite reduction is not well understood. The PdAu NPs were loaded into an amorphous silica support and evaluated for nitrite reduction in a batch reactor. Reaction followed pseudo first-order kinetics for greater than 80% of conversion. Catalyst activity showed volcano-like behavior with varying composition .... All PdAu alloys were significantly more active for nitrite reduction compared to pure Pd NPs, despite Au being catalytically inactive for hydrogenation. Sulfide fouling and catalyst longevity studies were conducted. The presence of Au in the catalyst structure did not appear to enhance resistance to sulfide fouling. Moreover, catalyst activity was reduced upon repeated cycles of nitrite reduction. Further investigation is required to understand the mechanism for catalyst deactivation.

Download or read book The Synthesis of Randomly Alloyed Palladium silver Nanoparticles for the Catalytic Treatment of Aqueous Nitrite written by Jacob Preston Troutman and published by . This book was released on 2019 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrate (NO3-), and its daughter compound nitrite (NO2-), are two of the most prevalent contaminants in drinking water. Catalytic degradation of NO3- and NO2- provides a treatment method with a small environmental footprint, though it is currently hindered by the need for a catalytic system that pairs reduced costs with enhanced activity and longevity. Monodisperse, randomly-alloyed palladium–silver nanoparticles (Pd [subscript X] Ag [subscript 100-X] NPs) with tunable compositions (X = 50–95) were studied for use as catalysts in aqueous NO2- reduction. The synthesized Pd [subscript X] Ag [subscript 100-X] NPs were supported on amorphous silica (SiO2) and studied for use as aqueous NO2- reduction catalysts in batch reactors with H2 gas as the electron donor. Nitrite reduction followed pseudo-first-order reaction kinetics for ≥80% conversion, and displayed a high selectivity (>98%) for nitrogen gas (N2) as the end product. Nearly all compositions displayed increased activity over pure PdNPs supported on amorphous SiO2. Catalyst longevity was assessed for the most active catalyst. Throughout recycling, the catalytic activity decreased, although complementary analysis indicated no major physical changes of the catalyst. Overall, this work demonstrates that incorporating inexpensive, semi-noble metals into bimetallic alloys is a potential avenue for increasing catalytic activity while decreasing catalyst cost for NO2- reduction

Download or read book Metal Nanoparticles for Catalysis written by Franklin (Feng) Tao and published by Royal Society of Chemistry. This book was released on 2014-06-30 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to the synthesis and applications of different nanocatalysts.

Download or read book Bimetallic Nanostructures written by Ya-Wen Zhang and published by John Wiley & Sons. This book was released on 2018-05-16 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systematically summarizes the current status and recent advances in bimetallic structures, their shape-controlled synthesis, properties, and applications Intensive researches are currently being carried out on bimetallic nanostructures, focusing on a number of fundamental, physical, and chemical questions regarding their synthesis and properties. This book presents a systematic and comprehensive summary of the current status and recent advances in this field, supporting readers in the synthesis of model bimetallic nanoparticles, and the exploration and interpretation of their properties. Bimetallic Nanostructures: Shape-Controlled Synthesis for Catalysis, Plasmonics and Sensing Applications is divided into three parts. Part 1 introduces basic chemical and physical knowledge of bimetallic structures, including fundamentals, computational models, and in situ characterization techniques. Part 2 summarizes recent developments in synthetic methods, characterization, and properties of bimetallic structures from the perspective of morphology effect, including zero-dimensional nanomaterials, one-dimensional nanomaterials, and two-dimensional nanomaterials. Part 3 discusses applications in electrocatalysis, heterogeneous catalysis, plasmonics and sensing. Comprehensive reference for an important multidisciplinary research field Thoroughly summarizes the present state and latest developments in bimetallic structures Helps researchers find optimal synthetic methods and explore new phenomena in surface science and synthetic chemistry of bimetallic nanostructures Bimetallic Nanostructures: Shape-Controlled Synthesis for Catalysis, Plasmonics and Sensing Applications is an excellent source or reference for researchers and advanced students. Academic researchers in nanoscience, nanocatalysis, and surface plasmonics, and those working in industry in areas involving nanotechnology, catalysis and optoelectronics, will find this book of interest.

Download or read book Preparation and Characterisation of Gold and Palladium Based Catalysts for the Direct Synthesis of Hydrogen Peroxide written by James Pritchard and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I The research presented in this thesis describes the direct synthesis of hydrogen peroxide from H2 and O2 using supported gold-palladium based catalysts. The direct synthesis process offers a green and sustainable approach compared to the anthraquinone autoxidation (AO) process, which is currently used on an industrial scale to produce >95% H2O2 worldwide. The work presented in this thesis is an attempt to examine the direct synthesis process in terms of determining optimum catalyst compositions for potential scale-up in the near-future. The primary aim of this investigation is centred on catalyst design and characterisation. The first part of this work is a catalyst optimisation study for 2.5 wt% Au-2.5 wt% Pd/TiO2, and involved changing the amount of water used in the catalyst preparation, in this case wet impregnation. It was found that the addition of small amounts of water resulted in approximately 100% enhancement in activity for TiO2-supported catalysts but not for carbonsupported Au-Pd catalysts. The rate of Au/Pd uptake was contrasted and it was determined that the isoelectric point of the support was highly influential. While the activity can be enhanced for TiO2-supported catalysts, both catalyst nanostructure and stability were detrimentally affected by the addition of water during the impregnation step. The second part of this work is focussed on understanding the precise nature of the acid pre-treatment effect, where treatment of a carbon support in dilute nitric acid prior to the impregnation of Au and Pd precursors can result in the complete switching-off of sequential H2O2 hydrogenation activity over the catalyst. Characterisation and heat treatment studies gave an improved understanding of the relationship between Au/Pd and the carbon support. The next part of the study addresses the use of a colloidal immobilisation method to pre-fabricate Au-Pd 'designer' nanoparticles onto supports and is accompanied by extensive advanced aberration corrected electron microscopy studies. The effect of acid pre-treating silica based supports is then considered for catalysts prepared by wet-impregnation, specifically the fact that acid pre-treatment of silica is required to induce synergy between Au and Pd metals for the direct synthesis of hydrogen peroxide. The final part of this work considers the effect of introducing a third metal into the catalyst design, specifically the addition of Pt to Au/Pd compositions. An extensive catalyst screening study is undertaken for Au-Pd-Pt/CeO2 catalysts.

Download or read book Metal Nanoparticles in Microbiology written by Mahendra Rai and published by Springer Science & Business Media. This book was released on 2011-04-02 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following an introduction to biogenic metal nanoparticles, this book presents how they can be biosynthesized using bacteria, fungi and yeast, as well as their potential applications in biomedicine. It is shown that the synthesis of nanoparticles using microbes is eco-friendly and results in reproducible metal nanoparticles of well-defined sizes, shapes and structures. This biotechnological approach based on the process of biomineralization exploits the effectiveness and flexibility of biological systems. Chapters include practical protocols for microbial synthesis of nanoparticles and microbial screening methods for isolating a specific nanoparticle producer as well as reviews on process optimization, industrial scale production, biomolecule-nanoparticle interactions, magnetosomes, silver nanoparticles and their numerous applications in medicine, and the application of gold nanoparticles in developing sensitive biosensors.

Download or read book Synthesis and Applications of Gold and Gold copper Alloy Nanoparticles written by Nathan E. Motl and published by . This book was released on 2012 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis of Palladium and Palladium copper Nanostructures as Electrocatalysts written by Haibin Wu and published by . This book was released on 2015 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pd and its alloys are alternatives of Pt as promising catalysts and electrocatalysts for many reactions. Size controlled synthesis of nanoparticles remains a major research subject, since smaller size particles show better catalytic performance. In this work, we developed a modified chemical wet method to prepare Pd and Pd-Cu nanostructures with uniform small size. Different sizes and shapes of Pd nanostructures were successfully synthesized by using the two reducing agents (i.e., L-ascorbyl-6-palmitate or phenylphosphinic acid). The reducing agents play a role to control the final morphologies and sizes of particles. The use of L-ascorbyl-6-palmitate favors to form irregular branch shapes or rods; in contrast, the use of phenylphosphinic acid tends to form spherical nanoparticles. Furthermore, phenylphosphinic acid can assist with size control of Pd particles. Co-reducing Pd and Cu precursors can obtain Pd-Cu nanostructures with different sizes and shapes. The growth mechanism is followed the deposition of Cu on Pd seeds which are reduced prior to Cu. Similar to pure Pd synthesis, phenylphosphinic acid reduced the precursors to form small uniform spherical particles compared to L-ascorbyl-6-palmitate. It was also found that the composition could also be tuned by using different reducing agents. The catalytic activity of Pd and Pd-Cu nanostructures for ethanol oxidation reaction (EOR) has been tested in basic solution for alkaline fuel cell applications. The specific areas of these Pd and Pd-Cu are much higher than those reported previously. It was found that both Pd and Pd-Cu nanostructures exhibited enhanced catalytic activities and to some extent resisted CO-like intermediates poisoning. Most catalysts had enhanced current densities after 500 cycle scan, indicating enhanced stability of those catalysts.

Download or read book Electrochemical Biosensors written by Serge Cosnier and published by CRC Press. This book was released on 2015-01-26 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Gold promoted Structurally Ordered Intermetallic Palladium Cobalt Nanoparticles for the Oxygen Reduction Reaction written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Considerable efforts to make palladium and palladium alloys active catalysts and a possible replacement for platinum have had a marginal success. Here, we report on a structurally ordered Au10Pd40Co50 catalyst that exhibits comparable activity to conventional platinum catalysts in both acid and alkaline media. Electron microscopic techniques demonstrate that via addition of gold atoms PdCo nanoparticles undergo at elevated temperatures an atomic structural transition from core-shell to a rare intermetallic ordered structure with twin boundaries forming stable, and facets. The superior stability of this catalyst compared to platinum after 10,000 potential cycles in alkaline media is attributed to the atomic structural order of PdCo nanoparticles along with protective effect of clusters of gold atoms on the surface. This strategy of making ordered palladium intermetallic alloy nanoparticles can be used in diverse heterogeneous catalysis where particle size and structural stability matters.

Download or read book Water soluble Palladium Nanoparticles for the Oxidation of Terminal Alkenes written by Edwin G. Avila (Graduate student) and published by . This book was released on 2021 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Green Synthesis of Nanoparticles Applications and Prospects written by Quaiser Saquib and published by Springer Nature. This book was released on 2020-10-19 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes various strategies for the synthesis of green nanoparticles using plant extracts and microbes, including the advantages and disadvantages of different methods and their applications. After discussing strategies for and the potential of green synthesis of noble metal nanoparticles, it highlights the role of the solvent system. The book then explores the stability/toxicity of nanoparticles and the associated-surface engineering techniques for achieving biocompatibility, and examines the antimicrobial efficacy of green nanoparticles with regard to various bacterial pathogens, as well as the underlying cytotoxicity mechanisms. Lastly, the book addresses the potential applications of various green nanoparticles in cancer theranostics, and reviews a number of plant-mediated nanoparticles as potential pharmaceutical agents. Given its scope, the book will be of interest to all scientists and students wanting to learn more about the synthesis and applications of green nanoparticles.

Download or read book Synthesis of Platinum palladium Alloy Nanocatalysts and Catalytic Activity for Emission Reactions written by Leslie Velasco and published by . This book was released on 2018 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimization of Carbon Supported Palladium and Gold Nanoparticles for Hydrodechlorination written by and published by . This book was released on 2018 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contamination of groundwater by trichloroethylene (TCE) and other related contaminants is a compromise to the safety of drinking water all over the world. There have been many efforts to solve this issue, but all possible solutions have come at the cost of excessive waste or further contamination of the environment. The Palladium (Pd), Gold (Au) coated, Carbon supported catalyst makes use of current nanotechnology to provide an efficient method of degrading TCE to non-toxic levels of ethene and ethane. This thesis discusses the optimization of the novel solvothermal, green synthesis process of Pd/Au carbon supported nanoparticles (NPs) devolved by the Jiao Group at Portland State University. The pre-sonication of Au precursor, washing of the carbon supported NP samples, and reaction time of the samples were explored. Evidence suggested that sonicating the Au precursor did not, alone, synthesize nanoparticles, washing the catalysts did provide an effective method of ensuring nanoparticles adhered to their support, and that a reaction time of down to an hour may be just as effective as a reaction time of 24 hours. The preliminary results gathered here are promising results to suggest the claims mentioned above but will require further investigation for a definitive confirmation.

Download or read book Nanostructured Catalysts for Environmental Applications written by Marco Piumetti and published by Springer. This book was released on 2022-01-21 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an overview of the recent studies and advances in environmental catalysis by nanomaterials, considering both the fundamental and the technological aspects. It offers contributions in different areas of environmental catalysis, including the catalytic and photocatalytic abatement of environmentally hazardous effluents from stationary or mobile sources, the valorization of waste and the production of sustainable energy. In other words, this monograph provides an overview of modern environmental and energy related applications with a particular emphasis to nano-sized catalytic materials. Recent concepts, experimental data and advanced theories are reported in this book to give evidence of the environmental and sustainable applications that can be found in the highly interdisciplinary field of catalysis.

Download or read book Elaboration And Applications Of Metal organic Frameworks written by Shengqian Ma and published by World Scientific. This book was released on 2018-01-31 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title takes researchers in as well as out of the field of metal-organic framework (MOF) and then guides them on a journey to rediscover and rethink how these designer coordination polymers will influence the realm of materials science. This book opens with a look at a deeply controversial issue, MOF stability, which has plagued many systems, but ultimately has led to better materials that proved to be more robust allowing them to be investigated for multiple applications. This book successfully highlights many of these useful applications that MOFs are well adapted for. Because MOF components, inorganic and organic, can combine the best of both chemical domains, MOFs will improve our environment by removing harmful contaminants from the air and water, reduce the energy required to perform chemical reactions, partition hard to separate molecular mixtures, and form the next-generation of magnetic and electronic materials. MOFs will eventually be used for everyday activities — for monitoring or reacting to changing conditions. Readers of this book can then take note and implement MOFs in their line of research.

Download or read book Water Encyclopedia Surface and Agricultural Water written by Jay H. Lehr and published by Wiley-Interscience. This book was released on 2005-06-01 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maximizing the use of our visible surface supplies in light of their greatest need in agriculture presents an enormous challenge throughout the world. New techniques in agricultural applications to preserve resources and increase yields are featured. Dams, lakes, and hydraulic features of surface water systems are amply covered, along with the importance of storm water management to growing communities.