Download or read book Design and Understanding of Selective Catalysts Using Colloidal Nanoparticle Synthesis written by Cody James Wrasman and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts are a critical component of the chemical industry that produces products that we rely on every day. A common geometry for industrial catalysts is comprised of metal nanoparticles dispersed on oxide supports. Numerous works have shown how control over the geometry of this catalyst motif can be leveraged to create catalysts with improved catalytic activity, selectivity, and stability. However, traditional catalyst synthesis techniques often do not provide the required control over important catalyst parameters such as nanoparticle size and alloy nanoparticle composition. In the works outlined in this thesis, colloidal synthesis is used to produce highly uniform nanoparticles with precise control over their geometry. First, a seed-mediated colloidal synthetic technique was developed to produce dilute (or single atom) alloy nanoparticles. Electron microscopy, UV-Vis spectroscopy, and X-ray absorption measurements were used to verify the formation of Pd/Au and Pd/Ag alloy nanoparticles with control over the Pd ensemble size down to single atoms. The Pd/Au nanoparticles were then used to carry out selective oxidation of alcohols in the presence of hydrogen and oxygen with attention paid to the impact of Pd ensemble size within Au on activity. It was found that Pd/Au alloy nanoparticles outperformed both pure metals, with the most dilute levels of Pd offering the largest improvement in catalytic activity while maintaining nearly complete selectivity to the desired product. Beyond improving catalytic activity, this work shows how the ability to tune several catalyst parameters independently enables better understanding of catalytic mechanisms. In particular, the mechanism of selective oxidation reactions in which a selective oxidant, likely hydrogen peroxide, is created from a mixture of hydrogen and oxygen over Au and Pd/Au catalysts are described. Through systematic testing, it was demonstrated that while Au nanoparticles need an interface with a metal oxide to produce the selective oxidant, Pd/Au nanoparticles carried out selective oxidation without contact with metal oxides. Furthermore, this work shows that once mobile oxidants are produced, they are able to diffuse through the catalytic bed do different catalytic sites. Beyond selective oxidation, this thesis describes how colloidal Ru nanoparticles can be used to determine the number of sites on an oxide support capable of hosting single metal atoms. This finding has implications for the creation of highly dispersed catalysts that exhibit reaction selectivity unique from nanoparticle catalysts. Despite its ability to create highly uniform catalysts, colloidal synthesis is currently mostly confined to the laboratory scale due to the relatively high cost and small scale at which nanoparticles are produced. While other groups are working to translate batch processes into continuous flow systems, little has been done to address the waste of expensive synthesis solvents that drive up the cost of colloidal nanoparticles. To address solvent waste, this work examines processes for recycling nanoparticle synthesis solvents and demonstrates the potential to produce uniform mono and bimetallic nanoparticles over many reuses. This work opens the door to closed loop processes where the colloidal nanoparticles are produced continuously requiring only metal precursors and a small amount of surfactants. Such a process would allow superior colloidal nanoparticle catalysts developed in the laboratory to be translated to more industrially relevant scales. Together, the projects outlined in this thesis demonstrate the potential of colloidally synthesized nanoparticles to improve the activity of selective catalytic reactions and to uncover mechanistic insights in complex, multi-site transformations. It also provides a scheme for how these and other laboratory scale discoveries can be transferred to industrial application.

Download or read book Nanoparticles in Catalysis written by Karine Philippot and published by John Wiley & Sons. This book was released on 2021-04-29 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoparticles in Catalysis Discover an essential overview of recent advances and trends in nanoparticle catalysis Catalysis in the presence of metal nanoparticles is an important and rapidly developing research field at the frontier of homogeneous and heterogeneous catalysis. In Nanoparticles in Catalysis, accomplished chemists and authors Karine Philippot and Alain Roucoux deliver a comprehensive guide to the key aspects of nanoparticle catalysis, ranging from synthesis, activation methodology, characterization, and theoretical modeling, to application in important catalytic reactions, like hydrogen production and biomass conversion. The book offers readers a review of modern and efficient tools for the synthesis of nanoparticles in solution or onto supports. It emphasizes the application of metal nanoparticles in important catalytic reactions and includes chapters on activation methodology and supported nanoclusters. Written by an international team of leading voices in the field, Nanoparticles in Catalysis is an indispensable resource for researchers and professionals in academia and industry alike. Readers will also benefit from the inclusion of: A thorough introduction to New Trends in the Design of Metal Nanoparticles and Derived Nanomaterials for Catalysis An exploration of Dynamic Catalysis and the Interface Between Molecular and Heterogeneous Catalysts A practical discussion of Metal Nanoparticles in Water: A Relevant Toolbox for Green Catalysis Organometallic Metal Nanoparticles for Catalysis A concise treatment of the opportunities and challenges of CO2 Hydrogenation to Oxygenated Chemicals Over Supported Nanoparticle Catalysts Perfect for catalytic, organic, inorganic, and physical chemists, Nanoparticles in Catalysis will also earn a place in the libraries of chemists working with organometallics and materials scientists seeking a one-stop resource with expert knowledge on the synthesis and characterization of nanoparticle catalysis.

Download or read book Selectivity in Catalysis written by Mark E. Davis and published by . This book was released on 1993 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Rational Design and Synthesis of Inorganic Nanostructures for Tandem Catalysis and CO2 Conversion written by Chenlu Xie and published by . This book was released on 2018 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject of this dissertation focuses on the design and synthesis of new catalysts with well-defined structures and superior performance to meet the new challenges in heterogenous catalysis. The past decade has witness the development of nanoscience as well as the inorganic catalysts for industrial applications, however there are still fundamental challenges and practical need for catalysis. Specifically, it is desirable to have the ability to selectivity produce complex molecules from simple components. Another great challenge faced by the modern industry is being environmentally friendly, and going for a carbon neutral economy would require using CO2 as feedstock to produce valuable products. The work herein focuses on the design and synthesis of inorganic nanocrystal catalysts that address these challenges by achieving selective and sequential chemical reactions and conversion of CO2 to valuable products. Chapter 1 introduces the development of heterogenous catalysis and the colloidal synthesis of metal nanoparticles catalysts with well-controlled structure. Tremendous efforts have been devoted to understanding the nucleation and growth process in the colloidal synthesis and developing new methods to produce metal nanoparticles with controlled sizes, shapes, composition. These well-defined catalytic system shows promising catalytic performance, which can be modulated by their structure (size, shape, compositions and the metal-oxide interfaces). The chapters hereafter explore the synthesis of new catalysts with controlled structures for catalysis. Chapter 2 presents the design and synthesis of a three dimensional (3D) nanostructured catalysts CeO2-Pt@mSiO2 with dual metal-oxide interfaces to study the tandem hydroformylation reaction in gas phase, where CO and H2 produced by methanol decomposition (catalyzed by CeO2-Pt interface) were reacted with ethylene to selectively yield propyl aldehyde (catalyzed by Pt-SiO2 interface). With the stable core-shell architecture and well-defined metal-oxide interfaces, the origin of the high propyl aldehyde selectivity over ethane, the dominant byproduct in conventional hydroformylation, was revealed by in-depth mechanism study and attributed to the synergybetween the two sequential reactions and the altered elementary reaction steps of the tandem reaction compared to the single-step reaction. The effective production of aldehyde through the tandem hydroformylation was also observed on other light olefin system, such as propylene and 1-butene. Chapter 3 expands the strategy of tandem catalysis into conversion of CO2 with hydrogen to value-added C2-C4 hydrocarbons, which is a major pursuit in clean energy research. Another well-defined 3D catalyst CeO2–Pt@mSiO2–Co was designed and synthesized, and CO2 was converted to C2-C4 hydrocarbons with 60% selectivity on this catalyst via reverse water gas shift reaction and subsequent Fischer–Tropsch process. In addition, the catalysts is stable and shows no obvious deactivation over 40 h. The successful production of C2−C4 hydrocarbons via a tandem process on a rationally designed, structurally well-defined catalyst demonstrates the power of sophisticated structure control in designing nanostructured catalysts for multiple-step chemical conversions. Chapter 4 turns to electrochemistry and apply the precision in catalyst structural design to the development of electrocatalysts for CO2 reduction. Herein, atomic ordering of bimetallic nanoparticles were synthetically tuned, from disordered alloy to ordered intermetallic, and it showed that this atomic level control over nanocrystal catalysts could give significant performance benefits in electrochemical CO2 reduction to CO. Atomic-level structural investigations revealed the atomic gold layers over the intermetallic core to be sufficient for enhanced catalytic behavior, which is further supported by DFT analysis.

Download or read book Design And Applications Of Single site Heterogeneous Catalysts Contributions To Green Chemistry Clean Technology And Sustainability written by John Meurig Thomas and published by World Scientific Publishing Company. This book was released on 2012-04-16 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: For far too long chemists and industrialists have relied on the use of aggressive reagents such as nitric and sulphuric acids, permanganates and dichromates to prepare the massive quantities of both bulk and fine chemicals that are needed for the maintenance of civilised life — materials such as fuels, fabrics, foodstuffs, fertilisers and pharmaceuticals. Such aggressive reagents generate vast quantities of environmentally harmful and often toxic by-products, including the oxides of nitrogen, of metal oxides and carbon dioxide.Now, owing to recent advances made in the synthesis of nanoporous solids, it is feasible to design new solid catalysts that enable benign, mild oxidants to be used, frequently without utilising solvents, to manufacture the products that the chemical, pharmaceutical, agro- and bio-chemical industries require. These new solid agents are designated single-site heterogeneous catalysts (SSHCs). Their principal characteristics are that all the active sites present in the high-area solids are identical in their atomic environment and hence in their energy of interaction with reactants, just as in enzymes.Single-site heterogeneous catalysts now occupy a position of growing importance both academically and in their potential for commercial exploitation. This text, the only one devoted to such catalysts, dwells both on principles of design and on applications, such as the benign synthesis of nylon 6 and vitamin B3. It equips the reader with unifying insights required for future catalytic adventures in the quest for sustainability in the materials used by humankind.Anyone acquainted with the language of molecules, including undergraduates in the physical and biological sciences, as well as graduates in engineering and materials science, should be able to assimilate the principles and examples presented in this book. Inter alia, it describes how clean technology and ‘green’ processes may be carried out in an environmentally responsible manner.

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 Tailored Metal Nanoparticles for Selective Catalysis written by Christine V. Gaskell and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of clean, sustainable chemical processes is a key priority towards meeting the growing demand for synthetic functional chemicals, while balancing rapidly depleting natural resources. The selective oxidation (selox) of crotyl alcohol to crotonaldehyde and the selective hydrogenation of benzyl cyanide to phenylethylamine are two specific systems for which, it is proposed, new heterogeneous catalysts and deeper mechanistic insight will improve. In this thesis the rational design of palladium catalysts is investigated for these systems, via synthesis of palladium nanoparticles with tailored morphology and palladium-gold nanoparticles with tuneable surface composition. Pd icosahedra, nanorods and nanocubes were synthesised and characterised extensively to confirm the size and morphology of the nanoparticles. Pd icosahedra are revealed to be three times more active for crotyl alcohol selox than the nanocubes, and ten times faster than the nanorods, while maintaining good selectivity. An Au-shell, Pd-core structure was synthesised, progressively annealed to induce alloying and characterised using various in situ spectroscopies. Surface Au was found to enhance crotyl alcohol selox activity and selectivity towards crotonaldehyde, in accordance with model predictions. An optimum crotonaldehyde yield was obtained for an Au40Pd60 surface alloy. By employing in situ and time-resolved spectroscopies the active site of Pd selox catalysts is examined, and the role of oxygen in this system and the catalyst's kinetic behaviour is defined. Reversible redox cycling of the catalyst dependent on its environment was observed, and it was possible to identify PdOx as the active catalytic species responsible for selectively oxidising crotyl alcohol to crotonaldehyde, with high temperatures suppressing catalytic selectivity. Systematic characterisation of an industrial carbon supported Pd catalyst, used in nitrile hydrogenation, reveals potential sources of deactivation including surface poisoning by CN species. Solutions to improve catalyst performance are proposed using the knowledge acquired from the nanoparticle catalysts' studies.

Download or read book Nanometal Catalysis in Organic Synthesis written by Ming Bao and published by Springer Nature. This book was released on with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Colloidal Nanoparticles for Heterogeneous Catalysis written by Priscila Destro and published by Springer. This book was released on 2019-02-04 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the formation of colloidal gold–copper (AuCu) alloy nanoparticles and evaluate their application in heterogeneous catalysis. Metal alloys are extremely versatile materials that have been used since the Antiquity to improve the properties of commonly used metals, therefore the understanding of their properties has fostered the applications in areas such as photonics, sensors, clinical diagnostics, and especially in heterogeneous catalysis, which allows catalyst active sites to be modulated. In this book, readers will appreciate the fundamental aspects involved in the synthesis of AuCu nanoalloys, including real-time information about their atomic organization, electronic properties, as well a deeper understand about the behavior of AuCu supported nanoalloys under real catalytic conditions, providing interesting insights about the effect of the support on the nanoalloy stability. The results presented here open new horizons for using metal alloys in catalysis and also other areas where the metal–support interface may play a crucial role.

Download or read book Monodisperse Metal Nanoparticle Catalysts on Silica Mesoporous Supports written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In addition, Pt-mesoporous silica core-shell structured NPs (Pt@mSiO2) were prepared, where the individual Pt NP is encapsulated by the mesoporous silica layer. The Pt@mSiO2 catalysts showed promising catalytic activity in high temperature CO oxidation. The design of catalytic structures with tunable parameters by rational synthetic methods presents a major advance in the field of catalyst synthesis, which would lead to uncover the structure-function relationships in heterogeneous catalytic reactions.

Download or read book Synthesis Characterization and Purification of Functional Nanomaterials written by James Morse and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the roles of inorganic nanomaterials continue to advance, precise control over property defining features such as composition, crystal structure, morphology and surface functionality becomes increasingly crucial. Colloidal synthesis employs solubilized chemical precursors to build materials from the bottom-up, providing an attractive method for generating nanoscale materials with extraordinary levels of control over material dimensions and morphology. In addition to the range of tunable synthetic parameters, colloidal syntheses offer solution dispersible nanoscale solids, which allows for convenient and high throughput liquid phase processing of the desired materials.Under the appropriate synthetic conditions, colloidally dispersed nanoparticle seeds can be used as structural foundations to nucleate and grow new material domains. Through this strategy, nanoparticles consisting of chemically distinct materials connected through solid state interfaces can be accessed. Dubbed hybrid nanoparticles, these materials constitute an expanding class of multi-component nanostructures that can exhibit multifunctionality as well as emergent phenomena not observed for the constituent materials independently. Moreover, these hybrids can adopt structures that expose multiple material domains to the surrounding media, allowing for additional synergies to be realized due to the distinct chemical surfaces arranged in close proximity. The unique features offered by these hierarchal nanostructures underpin, among many others, advanced applications in photovoltaics, biomedical theranostics, catalysis and chemical sensing.Although colloidal hybrid nanoparticles are attractive for a variety of applications, there are still significant hurdles that impair their widespread use. For example, the complex pathways that govern the heterogeneous nucleation and growth of these materials are not well understood, and accordingly, a robust synthetic framework for the modular design of hybrid structures from a diverse library of material combinations and connectivities has yet to be developed. In addition, current synthetic protocols for known colloidal hybrid architectures are nontrivial to execute, with run-to-run variability commonly observed among the product particle populations. For these reasons, studies that provide fundamental insights into colloidal reaction pathways, or offer robust strategies to access these materials in high quality, will enable key advancements in the future design and application of hybrid nanoparticle systems.In this dissertation, I present several contributions focusing on various aspects of inorganic colloidal nanoparticle chemistry. These contributions include chapters describing rigorous synthetic details as well as insights into the mechanistic pathways that govern the outcome of colloidal hybrid nanoparticle syntheses. Specifically, these studies center on the well known heterotrimer nanoparticle systems Ag-Pt-Fe3O4 and Au-Pt-Fe3O4, using them as model systems to provide generalizable insights into hybrid nanoparticle design and synthesis. In a subsequent chapter of this work, I describe new developments in the colloidal nanoparticle purification technique differential magnetic catch and release. This chapter demonstrates an alternative strategy to accessing predictable and high quality colloidal structures, by focusing on post synthetic purification rather than judicious synthetic control. Finally, an additional chapter of this dissertation describes a study investigating the selective hydrogenation of functionalized nitroarenes. These selective transformations typically require the application of complex nanoscale catalysts, which have complementary chemical surfaces in close proximity that are capable of cooperatively activating distinct reagent functionalities. The structural commonalities between heterostructured hybrid nanoparticles and these catalytic systems motivated us to investigate these transformations further and resulted in the unexpected discovery of bulk iron pyrite (FeS2) as an effective catalyst for these transformations.

Download or read book Catalyst Preparation written by John Regalbuto and published by CRC Press. This book was released on 2016-04-19 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text explores the optimization of catalytic materials through traditional and novel methods of catalyst preparation, characterization, and monitoring for oxides, supported metals, zeolites, and heteropolyacids. It focuses on the synthesis of bulk materials and of heterogeneous materials, particularly at the nanoscale. The final chapters examine pretreatment, drying, finishing effects, and future applications involving catalyst preparation and the technological advances necessary for continued progress. Topics also include heat and mass transfer limitations, computation methods for predicting properties, and catalyst monitoring on laboratory and industrial scales.

Download or read book Design of Heterogeneous Catalysts written by Umit S. Ozkan and published by John Wiley & Sons. This book was released on 2009-02-11 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-awaited reference source is the first book to focus on this important and hot topic. As such, it provides examples from a wide array of fields where catalyst design has been based on new insights and understanding, presenting such modern and important topics as self-assembly, nature-inspired catalysis, nano-scale architecture of surfaces and theoretical methods. With its inclusion of all the useful and powerful tools for the rational design of catalysts, this is a true "must have" book for every researcher in the field.

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 Nanocatalysis written by Ulrich Heiz and published by Springer Science & Business Media. This book was released on 2007-01-10 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocatalysis, a subdiscipline of nanoscience, seeks to control chemical reactions by changing the size, dimensionality, chemical composition, and morphology of the reaction center and by changing the kinetics using nanopatterning of the reaction center. This book offers a detailed pedagogical and methodological overview of the field. Readers discover many examples of current research, helping them explore new and emerging applications.

Download or read book Metal catalyzed Cross coupling Reactions written by François Diederich and published by John Wiley & Sons. This book was released on 2008-07-11 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon-carbon bond forming reactions are arguably the most important processes in chemistry, as they represent key steps in the building of complex molecules from simple precursors. Among these reactions, metal-catalyzed cross-coupling reactions are extensively employed in a wide range of areas of preparative organic chemistry, ranging from the synthesis of complex natural products, to supramolecular chemistry, and materials science. In this work, a dozen internationally renowned experts and leaders in the field bring the reader up to date by documenting and critically analyzing current developments and uses of metal-catalyzed cross-coupling reactions. A particularly attractive and useful feature, that enhances the practical value of this monograph, is the inclusion of key synthetic protocols, in experimental format, chosen for broad utility and application. This practice-oriented book can offer the practitioner short cuts to ensure they remain up-to-date with the latest developments.

Download or read book Modeling of Stimuli responsive Nanoreactors Rational Rate Control Towards the Design of Colloidal Enzymes written by Matej Kanduč and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In modern applications of heterogeneous liquid-phase nanocatalysis, the catalysts (e.g., metal nanoparticles) need to be typically affixed to a colloidal carrier system for stability and easy handling. "Passive carriers" (e.g., simple polyelectrolytes) serve for a controlled synthesis of the nanoparticles and prevent coagulation during catalysis. Recently, however, hybrid conjugates of nanoparticles and synthetic thermosensitive polymers have been developed that enable to change the catalytic activity of the nanoparticles by external triggers. In particular, nanoparticles embedded in a stimuli-responsive network made from poly (N-isopropylacrylamide) (PNIPAM) have become the most-studied examples of such hybrids. It has been demonstrated that the permeability of the polymer network and thus the reactant flux can be switched and controlled by external stimuli. Such "active carriers" may thus be viewed as true nanoreactors that open up new design routes in nano-catalysis and elevate synthesis to create highly selective, programmable "colloidal enzymes". However, only a comprehensive understanding of these materials on all time and length scales can lead to a rational design of future, highly functional materials. Here we review the current state of the theoretical and multi-scale simulation approaches, aiming at a fundamental understanding of these nanoreactors. In particular, we summarize a theoretical approach for reaction rates of surface-catalyzed bimolecular reactions in responsive nanoreactors in terms of the key material parameters, the polymer shell permeability Image ID:c9me00106a-t1.gif and the reactant partition ratio Image ID:c9me00106a-t2.gif. We discuss recent computer simulation studies of both atomistic and coarse-grained polymer models in which these quantities have been characterized in some detail. We conclude with an outlook on selected open questions and future theoretical challenges in nanoreactor modeling