Дисертації з теми "Functional Noble Metal Nanoparticle"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-36 дисертацій для дослідження на тему "Functional Noble Metal Nanoparticle".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Weerawardene, K. L. Dimuthu M. "Optical and luminescence properties of noble metal nanoparticles." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38189.
Повний текст джерелаDepartment of Chemistry
Christine M. Aikens
The remarkable optical and luminescence properties of noble metal nanoparticles (with diameters < 2 nm) attract researchers due to potential applications in biomedicine, photocatalysis, and optoelectronics. Extensive experimental investigations on luminescence properties of thiolate-protected gold and silver nanoclusters during the past decade have failed to unravel their exact photoluminescence mechanism. Herein, density functional and time-dependent density functional theory (DFT and TDDFT) calculations are performed to elucidate electronic-level details of several such systems upon photoexcitation. Multiple excited states are found to be involved in photoemission from Au₂₅(SR)₁₈– nanoclusters, and their energies agree well with experimental emission energies. The Au₁₃ core-based excitations arising due to electrons excited from superatom P orbitals into the lowest two superatom D orbitals are responsible for all of these states. The large Stokes shift is attributed to significant geometrical and electronic structure changes in the excited state. The origin of photoluminescence of Ag₂₅(SR)₁₈– nanoclusters is analogous to their gold counterparts and heteroatom doping of each cluster with silver and gold correspondingly does not affect their luminescence mechanism. Other systems have been examined in this work to determine how widespread these observations are. We observe a very small Stokes shift for Au₃₈(SH)₂₄ that correlates with a relatively rigid structure with small bond length changes in its Au₂₃ core and a large Stokes shift for Au₂₂(SH)₁₈ with a large degree of structural flexibility in its Au₇ core. This suggests a relationship between the Stokes shift of gold−thiolate nanoparticles and their structural flexibility upon photoexcitation. The effect of ligands on the geometric structure and optical properties of the Au₂₀(SR)₁₆ nanocluster is explored. Comparison of the relative stability and optical absorption spectra suggests that this system prefers the [Au₇(Au₈SR₈)(Au₃SR₄)(AuSR₂)₂] structure regardless of whether aliphatic or aromatic ligands are employed. The real-time (RT) TDDFT method is rapidly gaining prominence as an alternative approach to capture optical properties of molecular systems. A systematic benchmark study is performed to demonstrate the consistency of linear-response (LR) and RT-TDDFT methods for calculating the optical absorption spectra of a variety of bare gold and silver nanoparticles with different sizes and shapes.
Guidez, Emilie Brigitte. "Quantum mechanical origin of the plasmonic properties of noble metal nanoparticles." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/17314.
Повний текст джерелаDepartment of Chemistry
Christine M. Aikens
Small silver and gold clusters (less than 2 nm) display a discrete absorption spectrum characteristic of molecular systems whereas larger particles display a strong, broad absorption band in the visible. The latter feature is due to the surface plasmon resonance, which is commonly explained by the collective dipolar motion of free electrons across the particle, creating charged surface states. The evolution between molecular properties and plasmon is investigated. Time-dependent density functional theory (TDDFT) calculations are performed to study the absorption spectrum of cluster-size silver and gold nanorods. The absorption spectrum of these silver nanorods exhibits high-intensity longitudinal and transverse modes (along the long and short axis of the nanorod respectively), similar to the plasmons observed experimentally for larger nanoparticles. These plasmon modes result from a constructive addition of the dipole moments of nearly degenerate single-particle excitations. The number of single-particle transitions involved increases with increasing system size, due to the growing density of states available. Gold nanorods exhibit a broader absorption spectrum than their silver counterpart due to enhanced relativistic effects, affecting the onset of the longitudinal plasmon mode. The high-energy, high-intensity beta-peak of acenes also results from a constructive addition of single-particle transitions and I show that it can be assigned to a plasmon. I also show that the plasmon modes of both acenes and metallic nanoparticles can be described with a simple configuration interaction (CI) interpretation. The evolution between molecular absorption spectrum and plasmon is also investigated by computing the density of states of spherical thiolate-protected gold clusters using a charge-perturbed particle-in-a-sphere model. The electronic structure obtained with this model gives good qualitative agreement with DFT calculations at a fraction of the cost. The progressive increase of the density of states with particle size observed is in accordance with the appearance of a plasmon peak. The optical properties of nanoparticles can be tuned by varying their composition. Therefore, the optical behavior of the bimetallic Au[subscript](25-n)Ag[subscript]n(SH)[subscript]18[superscript]- cluster for different values of n using TDDFT is analyzed. A large blue shift of the HOMO-LUMO absorption peak is observed with increasing silver content, in accordance with experimental results.
Karimova, Natalia Vladimirovna. "Theoretical study of the optical properties of the noble metal nanoparticles: CD and MCD spectroscopy." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38177.
Повний текст джерелаDepartment of Chemistry
Christine M. Aikens
Gold and silver particles with dimensions less than a nanometer possess unique characteristics and properties that are different from the properties of the bulk. They demonstrate a non–zero HOMO–LUMO gap that can reach up to 3.0 eV. These differences arise from size quantization effects in the metal core due to the small number of atoms. These nanoparticles have attracted great interest for decades both in fundamental and applied research. Small gold clusters protected by various types of ligands are of interest because ligands allow obtaining gold nanoclusters with given sizes, shapes and properties. Three main families of organic ligands are usually used for stabilization of gold nanoclusters: phosphine ligands, thiolate ligands and DNA. Usually, optical properties of these NPs are studied using optical absorption spectroscopy. Unfortunately, sometimes this type of spectrum is poorly resolved and tends to appear very similar for different complexes. In these cases, circular dichroism (CD) and magnetic circular dichroism (MCD) spectroscopy can be applied. However, the interpretation of experimental CD and MCD spectra is a complicated process. In this thesis, theoretically simulated CD and MCD spectra were combined with optical absorption spectra to study optical activity for octa– and nona– and undecanuclear gold clusters protected by mono– and bidentate phosphine ligands. Additionally, optical properties of bare and DNA protected silver NPs were studied. Theoretical CD spectra were examined to learn more about the origin of chirality in chiral organometallic complexes, and to contribute to the understanding of the difference in chiroptical activity of gold clusters stabilized by different phosphine ligands and DNA–stabilized silver clusters. Furthermore, optical properties of the small centered gold clusters Au₈(PPh₃)₈²⁺ and Au₉(PPh₃)₈³⁺ were examined by optical absorption and MCD spectra using TDDFT. Theoretical MCD spectra were also used to identify the plasmonic behavior of silver nanoparticles. These results showed that CD and MCD spectroscopy yield more detailed information about optical properties and electronic structure of the different chemical systems than optical absorption spectroscopy alone. Theoretical simulation of the CD and MCD spectra together with optical absorption spectra can be used to assist in the understanding of empirically measured CD and MCD and provide useful information about optical properties and electronic structure.
Herrmann, Anne-Kristin. "Preparation, Processing and Characterization of Noble Metal Nanoparticle-based Aerogels." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-149672.
Повний текст джерелаGill, Arran Michael. "The extrusion of noble metal nanoparticle catalysts for sustainable oxidation reactions." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/422157/.
Повний текст джерелаCrites, Charles-Oneil. "Investigating the Interactions between Free Radicals and Supported Noble Metal Nanoparticles in Oxidation Reactions." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33404.
Повний текст джерелаNear, Rachel Deanne. "Theoretical and experimental investigation of the plasmonic properties of noble metal nanoparticles." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52181.
Повний текст джерелаBruzas, Ian R. "Biocompatible noble metal nanoparticle substrates for bioanalytical and biophysical analysis of protein and lipids." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553250462519941.
Повний текст джерелаJOUVE, ANDREA. "VALORISATION OF BIOMASS-DERIVED MOLECULES BY NOBLE METAL CATALYSTS." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/710533.
Повний текст джерелаSinha, Roy Rajarshi. "Ab initio simulation of optical properties of noble-metal clusters." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0017/document.
Повний текст джерелаThe fundamental research interest in nanometric pieces of noble metals is mainly due to the localized surface-plasmon resonance (LSPR) in the optical absorption. Different aspects related to the theoretical understanding of LSPRs in `intermediate-size' noble-metal clusters are studied in this thesis. To gain a broader perspective both the real-time \ai formalism of \td density-functional theory (RT-TDDFT) and the classical electromagnetics approach are employed. A systematic and detailed comparison of these two approaches highlights and quantifies the limitations of the electromagnetics approach when applied to quantum-sized systems. The differences between collective plasmonic excitations and the excitations involving $d$-electrons, as well as the interplay between them are explored in the spatial behaviour of the corresponding induced densities by performing the spatially resolved Fourier transform of the time-dependent induced density obtained from a RT-TDDFT simulation using a $\delta$-kick perturbation. In this thesis, both bare and ligand-protected noble-metal clusters were studied. In particular, motivated by recent experiments on plasmon emergence phenomena, the TDDFT study of Au-Cu nanoalloys in the size range just below 2~nm produced subtle insights into the general effects of alloying on the optical response of these systems
Leyßner, Felix [Verfasser]. "Analysis of functional organic molecules at noble metal surfaces by means of vibrational spectroscopies / Felix Leyßner." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1026265657/34.
Повний текст джерелаHerrmann, Anne-Kristin Verfasser], Alexander [Akademischer Betreuer] Eychmüller, and Stefan [Akademischer Betreuer] [Kaskel. "Preparation, Processing and Characterization of Noble Metal Nanoparticle-based Aerogels / Anne-Kristin Herrmann. Gutachter: Alexander Eychmüller ; Stefan Kaskel. Betreuer: Alexander Eychmüller." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1069040401/34.
Повний текст джерелаHerrmann, Anne-Kristin [Verfasser], Alexander Akademischer Betreuer] Eychmüller, and Stefan [Akademischer Betreuer] [Kaskel. "Preparation, Processing and Characterization of Noble Metal Nanoparticle-based Aerogels / Anne-Kristin Herrmann. Gutachter: Alexander Eychmüller ; Stefan Kaskel. Betreuer: Alexander Eychmüller." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1069040401/34.
Повний текст джерелаArtuc, Zuleyha. "Density Functional Theory Investigation Of Noble Metal Reduction Agents On Gamma-al2o3 In Nox Storage/reduction Catalysis." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613756/index.pdf.
Повний текст джерелаAsara, Gian Giacomo. "Transition metal carbides as active phase and as support in catalysis: Insights from first principles theoretical modelling." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/454774.
Повний текст джерелаLos carburos de metales de transición (TMC) exhiben propiedades químicas y catalíticas similares a las de los costosos metales nobles. La conversión de alcohol, hidrogenación de olefinas y otras reacciones importantes han demostrado la aplicabilidad de estos compuestos en procesos industriales. También se sabe que nanopartículas de metales nobles (NMNPs) muestran una alta actividad catalítica a pesar de la baja o nula reactividad del metal sólido. Además, investigaciones recientes señalan que los soportes de TMC polarizan la densidad electrónica de NMNPs adsorbidos y aumentan la actividad catalítica respecto a los soportes más tradicionales de óxido metálico. Estos descubrimientos recientes han inspirado el trabajo presentado en esta tesis, realizado mediante técnicas actuales de la química cuántica. Se ha estudiado CO, CO2, H2, H2O adsorbidos sobre TiC y sobre pequeños clusters de oro adsorbidos sobre el suport. Se ha considerado la superficie (001), terrazas, escalones monoatómicos y defectos y, también, la reactividad de las moléculas adsorbidas sobre la superficie limpia de TiC (001) y en dos clusters de oro, Au4 y Au6, adsorbidos. Las barreras energéticas calculadas para la formación de metano o formaldehído a partir de gas de síntesis en la superficie limpia de TiC (001) resultan ser demasiado altas y esos procesos son inviables sobre el soporte limpio. Sobre los clusters de oro soportados sobre TiC (001) hay una mayor actividad catalítica, pero la reacción continúa siendo altamente impedida. Sin embargo la reacción de desplazamiento del gas de agua se prevé que sea rápida en el sistema Au4/TiC (001), superando los catalizadores utilizados normalmente en la industria. Experimentos recientes muestran que los clusters de Ni, Cu y Au están fuertemente deformados una vez adsorbidos sobre TMC dando lugar en catalizadores muy activos. Se ha investigado la interacción de los átomos con la fase delta del catalizador de MoC. La interacción es más fuerte para el recubrimiento más bajo considerado, la relajación de la superficie es importante y la actividad se prevé que aumente en el orden Ni> Cu> Au. Finalmente, se han considerado posibles reconstrucciones no polares para la superficie (001) de Mo2C centrándose en la energía de escisión, que es proporcional a la estabilidad de cada tipo de terminación. Las reconstrucciones no polares disminuyen la energía de escisión, confirmando la aplicabilidad de los conceptos clásicos de Tasker para óxidos a los TMC.
Carbides of the early transition metals (TMC) exhibit chemical and catalytic properties that in many aspects are very similar to those of expensive noble metals. Alcohol conversion, hydrogenation of olefins and many others important reactions demonstrated the applicability of these compounds for industrial processes. It is also known that small noble metal nanoparticles (NMNPs) show high catalytic activity despite of the poor reactivity or inertness of the bulk metal. Additionally, recent investigations pointed out that supporting TMCs polarize the electron density of adsorbed NMNPs increasing the catalytic activity respect to more traditional metal oxide supports. These recent discoveries inspired the work reported in this thesis using state-of-the-art quantum chemical techniques. We studied CO, CO2, H2, H2O molecules adsorbed on TiC and on small gold clusters adsorbed thereon. We considered the (001) extended surface, terraces, monatomic steps and kink defective sites. The reactivity of adsorbed molecules on the clean TiC (001) surface and on two gold clusters, Au4 and Au6, adsorbed thereon were also studied. Energy barriers calculated for methane or formaldehyde formation from syngas, on the clean TiC (001) surface were by far too high and those processes are unviable on the clean support. Gold clusters supported by TiC (001) show higher catalytic activity but the reaction continues to be highly hindered. However water gas shift reaction is predicted to be fast on the Au4/TiC(001) system, overtaking catalysts normally used in industry. Recent experiments show that Ni, Cu and Au clusters are strongly perturbed upon adsorption on TMC resulting in extremely active catalysts. We investigated the interaction of those atoms with the delta phase of the MoC catalyst. The interaction is stronger for the lowest coverage considered, the relaxation of the surface important and the activity is predicted to increase in the order Ni>Cu >Au. Finally, we have studied possible non-polar reconstructions of the (001) surface of Mo2C focusing on the cleavage energy, proportional to the stability of each type of termination. The non-polar reconstructions decreased the calculated cleavage energy, confirming the applicability of the classical Tasker’s concepts for oxides to TMCs.
Martelli, Francesca. "Supported metal nanoparticles for sustainable green catalytic processes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20699/.
Повний текст джерелаArnedo-Sanchez, Leticia. "Lanthanide and transition metal complexes as building blocks for supramolecular functional materials." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF047.
Повний текст джерелаThis thesis deals with coordination compounds based on transition metals and lanthanides as key components of functional materials. Besides a brief summary of photophysics, supramolecular gels and metal nanoparticles, an overview of the instruments and techniques employed in this work is included. This thesis is further divided into four chapters focused on optically active metalcomplexes (chapters 3 and 4), stimuli responsive metallogels (chapter 5) and functionalized nanomaterials for sensing applications (chapter 6). In chapter 3, the synthesis and characterization of anionic lanthanide complexes is reported. Analytical techniques, emission spectroscopy and X-ray crystallography were employed to characterize these complexes. ln chapter 4, the study of light emitting metal complexes is extended to transition metal complexes, in particular to iridium (lll) complexes. A family of neutral bis-cyclometallated iridium (lll) complexes that exhibit an intense red emission under photo- or electro-excitation is studied. ln chapter 5 the design and investigation of a new family of low molecular weight gelators based on perfluorinated terpyridines is reported. The morphology and mechanical and thermodynamical properties of these metallogels is studied. Chapter 6 studies the excellent cooperation between coordination compounds and nanomaterials to yield optical sensors. A new colorimetric sensor for pyrophosphate consisting of gold nanoparticles acting as reporting units functionalized with a thiol-modified aminoterpyridine-Zn complex is described
Hejazi, Seyedsina [Verfasser], Hiroaki [Akademischer Betreuer] Tsuchiya, and Patrik [Gutachter] Schmuki. "Utilization of noble metal co-catalysts on TiO2 for photocatalytic H2 production: from nanoparticle positioning to single-atom catalysis / Seyedsina Hejazi ; Gutachter: Patrik Schmuki ; Betreuer: Hiroaki Tsuchiya." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1220505986/34.
Повний текст джерелаOh, Seung Cheol [Verfasser], Johannes [Akademischer Betreuer] Barth, and Markus [Akademischer Betreuer] Lackinger. "Single layer films of functional molecules on noble metal surfaces visited by scanning tunneling microscopy and X-ray spectroscopy / Seung Cheol Oh. Gutachter: Johannes Barth ; Markus Lackinger. Betreuer: Johannes Barth." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1060825449/34.
Повний текст джерелаMIGLIORINI, LORENZO. "DEVELOPMENT OF FUNCTIONAL NANOCOMPOSITE MATERIALS TOWARDS BIODEGRADABLE SOFT ROBOTICS AND FLEXIBLE ELECTRONICS." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/704286.
Повний текст джерелаGrillet, Nadia. "Réponse optique de nano-objets uniques d’argent : couplage plasmonique et photo-oxydation." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10135/document.
Повний текст джерелаThe optical properties of noble metal nanoparticles are known to be dominated by the localized surface plasmon resonance (SPR) which is highly sensitive to the size of the particles, their shape, their environment, and eventually their chemical composition in the case of mixed systems. In order to study the optical response of a single supported metallic nanoparticle, a high sensitive spectroscopic setup using a white lamp (300-900 nm) has been developed in a transmission measurement configuration. This technique, the Spatial Modulation Spectroscopy, aims to detect the overall extinction of light by a nanoparticle. Moreover, the coupling of this technique with the direct observation of the particles by Transmission Electron Microscopy allows to get an unambiguous description of their optical response in relation with their exact morphology. In this work, the optical response of single silver nano-objects has been correlated with their morphology and their structure at a sub-nanometer scale. Time evolution of the optical response of single silver nanocubes under illumination was first investigated. We observed a “spherization” and a photo-oxidation due to the UV part of the light. Moreover, we studied pairs of cubic silver nanoantennas that showed a huge sensitivity of their optical response with the interparticle distance and their morphology. Indeed, the SPR is red-shifted with decreasing interparticle distance. One can also observe a striking splitting of the resonance for very low interparticle distances. Preliminary DDA calculations seem to show that the radius of curvature at the corners and edges of both cubes plays a key role in the splitting of the resonance
Hughes, Zak E., and T. R. Walsh. "Non-covalent adsorption of amino acid analogues on noble-metal nanoparticles: influence of edges and vertices." 2016. http://hdl.handle.net/10454/15841.
Повний текст джерелаThe operation of many nanostructured biomolecular sensors and catalysts critically hinges on the manipulation of non-covalent adsorption of biomolecules on unfunctionalised noble-metal nanoparticles (NMNPs). Molecular-level structural details of the aqueous biomolecule/NMNP interface are pivotal to the successful realisation of these technologies, but such experimental data are currently scarce and challenging to obtain. Molecular simulations can generate these details, but are limited by the assumption of non-preferential adsorption to NMNP features. Here, via first principles calculations using a vdW-DF functional, and based on nanoscale sized NMNPs, we demonstrate that adsorption preferences to NP features vary with adsorbate chemistry. These results show a clear distinction between hydrocarbons, that prefer adsorption to facets over edges/vertices, over heteroatomic molecules that favour adsorption onto vertices over facets. Our data indicate the inability of widely used force-fields to correctly capture the adsorption of biomolecules onto NMNP surfaces under aqueous conditions. Our findings introduce a rational basis for the development of new force-fields that will reliably capture these phenomena.
Halder, Aditi. "Functional Noble Metal, Bimetallic And Hybrid Nanostructures By Controlled Aggregation Of Ultrafine Building Blocks." Thesis, 2009. https://etd.iisc.ac.in/handle/2005/978.
Повний текст джерелаHalder, Aditi. "Functional Noble Metal, Bimetallic And Hybrid Nanostructures By Controlled Aggregation Of Ultrafine Building Blocks." Thesis, 2009. http://hdl.handle.net/2005/978.
Повний текст джерелаLeonard, Donovan N. "Bio-related noble metal nanoparticle structure property realtionships." 2007. http://www.lib.ncsu.edu/theses/available/etd-03202007-234527/unrestricted/etd.pdf.
Повний текст джерела"Noble metal nanoparticle-loaded mesoporous oxide microspheres for catalysis." 2012. http://library.cuhk.edu.hk/record=b5549563.
Повний текст джерела本論文首先介紹了一步法製備貴金屬納米顆粒負載的金屬氧化物微纳米球及其在催化反应中的應用。我們選擇了金、鉑和鈀來分別負載在二氧化鈦、二氧化鋯和三氧化二鋁微納米球上。這幾種貴金屬和氧化物都是在環境污染控制、石油化工產業和醫藥產業中具有代表性的催化劑及襯底。除了檢測我們所製備的微納米顆粒的結構形貌等特徵外,我們還利用對硝基苯酚還原為對胺基苯酚的這個催化反應檢驗了這些貴金屬納米顆粒負載的氧化物微納米球的催化活性。考慮到三種貴金屬和三種氧化物的排列組合,以及金屬含量可能產生的影響,我們準備了九類共18份樣品,逐個進行催化反應。最後的結果顯示,含鈀0.1%摩爾比例的二氧化鈦表現出最強的催化活性。同时,這種方法也可以推廣到其他的貴金屬以及氧化物襯底,從而可以簡單方便地製備各种氧化物负载貴金屬催化劑,并可以對他們之間的協同作用進行研究。
此外,我根據同樣的超聲噴霧法製備了貴金屬負載的空心介孔氧化物微納米球。這個研究課題引入了聚苯乙烯球作為模板。同時利用聚苯乙烯球表面修飾過的金屬納米顆粒之间的相互作用,實現了金屬納米顆粒在球表面的吸附,进而聚苯乙烯球可以作為載體將金屬納米顆粒帶入介孔氧化物中。通過熱分解將聚苯乙烯球除去後,金屬納米顆粒就可以吸附在空心介孔氧化物球的內表面。在這個實驗中,我們先製備好據有特殊形貌的金屬納米顆粒,比如金納米棒、鈀納米立方体和金納米棒外面包覆鈀的納米殼鞘結構。然後借助聚苯乙烯球將其帶入介孔二氧化鈦和二氧化鋯及二氧化硅中。在對硝基苯酚還原的實驗中,这种介孔微纳米球表现出良好的催化性能并在一定程度上提高了催化剂的循环性。
为了尽可能的提高催化剂的循环性,我希望能獲得據有良好磁性的介孔微納米球。我們嘗試了兩種方法,一是將磁性納米顆粒比如鐵的氧化物納米顆粒引入介孔氧化物微納米球,另一種方法是製備據有磁性的介孔氧化鐵微納米球。我们相信通過這種方法,貴金屬納米顆粒負載的介孔氧化物微納米球的催化性能,尤其是循環性能必然會顯著的提高。
Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles.
I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO₂, ZrO₂, Al₂O₃) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular reaction, I found that Pd nanoparticles supported on mesoporous TiO₂ exhibit the best catalytic performance. The demonstrated low-cost and high-productivity preparation method can be extended to other catalysts, which can contain various metals and oxide substrates and will have high potential for industrial applications. Our preparation method also provides a platform for the studies of the synergetic catalytic effects between different oxide substrates and metals.
I further fabricated hollow mesoporous microspheres containing differently shaped noble metal nanocrystals. Hollow structures are strongly desired in many applications because of their high pore volumes, surface areas, and possible light-trapping effect. In my study, the hollow structures were obtained by simply dispersing polystyrene (PS) nanospheres into the precursor solution for aerosol spray. The PS spheres were removed by thermal calcination to produce hollow mesoporous microspheres. In my first study, the noble metal salts were dissolved in the precursor solutions, and the noble metal nanoparticles were obtained through thermal calcination. In this way, the size and shape of the metal nanoparticles cannot be well controlled. In my second study, I first grew noble metal nanocrystals and then incorporated them into the oxide supports. This preparation route allowed me to incorporate metal nanocrystals with controlled sizes, shapes, and compositions into the oxide matrices. The metal nanocrystals I used in this experiment included Pd nanocubes, Au nanorods, and Au corePd shell nanorods. These nanocrystals were functionalized with thiol-terminated methoxypoly(ethylene glycol) . The surface functionalization allowed them to adsorb on the PS spheres. After thermal calcination, the noble metal nanocrystals were left inside and adsorbed on the inner surface of the hollow mesoporous metal oxide microspheres. I investigated the catalytic activities of the Pd nanocube-embedded hollow mesoporous TiO₂ and ZrO₂ microspheres for the reduction of 4-nitrophenol to 4-aminophenol. I also examined the recyclability of the Pd nanocube-embedded hollow mesoporous ZrO₂ microsphere catalysts. The results showed that the combination of the noble metal nanocrystals and oxides prevents the aggregation of the nanostructures and reduces the loss of the catalysts during the recycling processes, leading to the remarkable recyclability of the hybrid catalyst. This method for the preparation of noble metal nanostructure-embedded hollow mesoporous oxide microspheres can greatly facilitate the investigation on the catalytic properties of noble metal nanocrystal and metal oxide hybrid nanostructures and therefore guide the design and fabrication of high-performance catalysts.
Last but not least, I investigated the magnetic mesoporous microspheres to enable a better recyclability of the mesoporous oxide catalysts. Both magnetic nanoparticle-included mesoporous metal oxides and mesoporous magnetic oxides were presented. The successfully syntheses of these microspheres will greatly improve the catalytic performance of the noble metal nanoparticle-loaded mesoporous oxide microspheres.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Jin, Zhao = 貴金屬納米顆粒負載的介孔金屬氧化物微納米球及其催化應用 / 金釗.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
Jin, Zhao = Gui jin shu na mi ke li fu zai de jie kong jin shu yang hua wu wei na mi qiu ji qi cui hua ying yong / Jin Zhao.
Abstract --- p.i
摘要 --- p.iii
Acknowledgement --- p.v
Table of Contents --- p.vii
List of Figures --- p.x
List of Tables --- p.xvii
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Mesoporous metal oxide materials --- p.1
Chapter 1.1.1 --- Overview on mesoporous materials --- p.1
Chapter 1.1.2 --- Syntheses of mesoporous metal oxides --- p.3
Chapter 1.1.2.1 --- Preparation of mesoporous metal oxides through soft-templating methods --- p.3
Chapter 1.1.2.2 --- Preparation of mesoporous metal oxides through hard-templating methods --- p.8
Chapter 1.1.3 --- Applications of mesoporous metal oxides --- p.11
Chapter 1.1.3.1 --- Catalysis --- p.12
Chapter 1.1.3.2 --- Energy conversion and storage --- p.13
Chapter 1.1.3.3 --- Sensing --- p.13
Chapter 1.2 --- Noble metal nanopartilces --- p.15
Chapter 1.2.1 --- Overview of noble metal nanoparticles --- p.15
Chapter 1.2.2 --- Catalytic applications of noble metal nanoparticles --- p.19
Chapter 1.2.2.1 --- Automotive converter --- p.19
Chapter 1.2.2.2 --- Suzuki cross-coupling reaction --- p.20
Chapter 1.3 --- The overview of this thesis --- p.22
References --- p.24
Chapter 2 --- Ultrasonic Aerosol Spray --- p.30
Chapter 2.1 --- Working principle and our ultrasonic aerosol spray system --- p.30
Chapter 2.2 --- Materials synthesized by the AASA method --- p.34
References --- p.37
Chapter 3 --- Materials Characterization Methods and Catalytic Studies --- p.39
Chapter 3.1 --- Characterization methods --- p.39
Chapter 3.2 --- Model catalytic reaction --- p.41
References --- p.45
Chapter 4 --- Noble Metal Nanoparticle-Loaded Mesoporous Oxide Microspheres --- p.46
Chapter 4.1 --- Experiments --- p.48
Chapter 4.2 --- Results and discussion --- p.50
Chapter 4.2.1 --- Mesoporous metal oxide microspheres --- p.50
Chapter 4.2.2 --- Noble metal nanoparticle-loaded mesoporous oxide microspheres --- p.55
Chapter 4.3 --- Summary --- p.73
References --- p.75
Chapter 5 --- Metal Nanostructure-Embedded Hollow Mesoporous Oxide Microspheres Prepared with Polystyrene Nanospheres as Carriers and Templates --- p.78
Chapter 5.1 --- Experiments --- p.83
Chapter 5.2 --- Results and discussion --- p.88
Chapter 5.2.1 --- Hollow mesoporous oxide microspheres prepared with the PS spheres as templates --- p.88
Chapter 5.2.2 --- Noble metal nanostructure-embedded hollow mesoporous oxide microspheres --- p.90
Chapter 5.3 --- Summary --- p.106
References --- p.108
Chapter 6 --- Magnetic Mesoporous Microspheres --- p.113
Chapter 6.1 --- Experiment --- p.115
Chapter 6.2 --- Results and discussion --- p.117
Chapter 6.2.1 --- Magnetic nanoparticle-included mesoporous TiO₂ microspheres --- p.117
Chapter 6.2.2 --- Mesoporous iron oxide microspheres --- p.125
Chapter 6.3 --- Summary --- p.128
References --- p.130
Chapter 7 --- Conclusions --- p.131
Herrmann, Anne-Kristin. "Preparation, Processing and Characterization of Noble Metal Nanoparticle-based Aerogels." Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A28215.
Повний текст джерелаChen, Yu-Chi, and 陳羽綺. "Preparation and Application of Alkyl Silicone Polymer Noble Metal Nanoparticle Catalyst Ink." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/17740975276221108147.
Повний текст джерела國防大學理工學院
化學工程碩士班
102
In this study, the preparation of St-co-MPS copolymer with both styrene(St) monomer and γ-methacryloxypropyltrimethoxysilane (γ-MPS) monomer by free radical polymerization. Poly(St-co-MPS)/Pd was prepared via self-reduction of palladium ions by St-co-MPS oligomer without using any reducing agent or surfactant. It was shown that Pd was reduced by the chain-end sulfate groups of styrene when copolymer reacted with the metallic ions. These St-co-MPS copolymer was characterized by 13C-NMR, 29Si-NMR and FTIR to confirm polymer composition and quantity sulfonation, and those self-assembly polymer-metal nanocomposites were characterized by electron microscopy (TEM), observe the stability of LU Misizer(LUM). The Poly(St-co-MPS)/Pd used as ink for catalytic pattern of glasses, which allows to from the metallic pattern by electroless deposition. The cross-linking extend of Poly(St-co-MPS)/Pd ink and glasses dipping with different pH condition was characterized by X-ray photoelectron spectroscope(XPS) to enhance the adhesion of the Poly(St-co-MPS)/Pd ink and glass substrate. The pattern thickness of Ni layer about 8.51 μm. Finally, we used Inkjet printing metallization process has been used in the fabricated of mobile antenna on special glass case, The WWAN five band antenna was made on the new glass case substrate by the printing of the catalyst activation and electroless plating forming the metal pattern. It will simplify the institutions of the antenna, and resolve the configuration problems of the limited space in the mobile phone's.
Wei, Yunle. "Noble metal nanoparticles in glass: A universal pathway towards light modulation." Thesis, 2019. http://hdl.handle.net/2440/124225.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2019
Jian, Shiou-Jen, and 簡秀真. "Noble Metal Nanoparticle Modified WO3 Nanowire Arrays for the Enhancement of Photoelectrochemical Hydrogen Generation under Solar Light Illumination." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/09202803944132973653.
Повний текст джерелаGULLACE, SARA. "Noble metal nanoparticles as active materials for solar energy conversion and chemical sensing." Doctoral thesis, 2020. http://hdl.handle.net/11570/3181468.
Повний текст джерелаDuoss, Eric Brian. "Nanoparticle and sol-gel inks for direct-write assembly of functional metallic and metal oxide materials /." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3362776.
Повний текст джерелаSource: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3724. Adviser: Jennifer A. Lewis. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.
Liu, Po-Chun, and 劉柏均. "Development of New Multicoeffient Density Functional Theory for Main-Group and Transition Metal Chemistry ; Reaction Dynamics Study of Noble-Gas Exchange Reactions." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/87548192189876943260.
Повний текст джерела國立中正大學
化學暨生物化學研究所
102
This thesis consists of three chapters. In chapter 1, we applied the multi-coefficient density functional theory (MC-DFT) to a few recent Minnesota functionals. In chapter 2, we have developed a new method using mixed functionals and we tested it on 70 bond energies of 3d transition-metal-containing molecules. In chapter 3, we investigated the kinetic isotope effects and tunneling effects of noble-gas exchange reactions. In chapter 1, we have applied MC-DFT method to four recent Minnesota functionals, including M06-2X, M08-HX, M11, and MN12-SX on the performance of thermochemical kinetics. The results indicated that the accuracy can be improved significantly by using two or three basis sets. We further included the SCS-MP2 energies into MC-DFT, and the resulting mean unsigned errors (MUE) decreased by ~0.3 kcal/mol for the most accurate basis set combinations. The M06-2X functional with the simple [6-311+G(d,p)/6-311+G(2d,2p)] combination gave the best performance/cost ratios for the MC-DFT and MC-SCS-MP2 | MC-DFT methods with MUE of 1.58 and 1.22 kcal/mol, respectively. In chapter 2, we have developed a new method using mixed functionals for transition metals. This method was tested against a database including 70 bond energies of 3d transition-metal-containing molecules with small experimental uncertainties. The best mixed functional method was the τ-HCTHhyb/mPW2-PLYP combination, and it yielded an MUE of 5.49 kcal/mol. In comparison, the single τ-HCTHhyb and mPW2-PLYP functional gave MUEs of 6.14 and 12.88 kcal/mol, respectively. We also applied the MC-DFT approach into the mixed functional and it yielded an MUE of 4.94 kcal/mol. We further added the MP2 and CCSD energies into the new method, and obtained MUE of 4.75 kcal/mol and 4.51 kcal/mol, respectively. In chapter 3, we used VTST/MT method to investigate four noble-gas exchange reactions: Ng’ + HNBNg+ (Ng, Ng’ = He, Ne, and Ar). The barrier heights of these four reactions were predicted to be 5-9 kcal/mol. The calculated results showed significant tunneling effects even at room temperature, especially for the He + HNBHe+ reaction. All reactions showed very significant tunneling effects at low temperature. For helium exchange reactions, the internal helium atom (in the cation) contributed more in the tunneling effects than the external helium atom (the neutral reactant) at low temperature.
Javier, Alnald Caintic. "Integrating Experiment and Theory in Electrochemical Surface Science: Studies on the Molecular Adsorption on Noble-Metal Electrode Surfaces by Density Functional Theory, Electron Spectroscopy, and Electrochemistry." Thesis, 2013. http://hdl.handle.net/1969.1/151363.
Повний текст джерелаAnumol, E. A. "Mechanisms of Formation and Thermal Stabililty of Functional Nanostructures." Thesis, 2012. http://etd.iisc.ac.in/handle/2005/3163.
Повний текст джерелаAnumol, E. A. "Mechanisms of Formation and Thermal Stabililty of Functional Nanostructures." Thesis, 2012. http://hdl.handle.net/2005/3163.
Повний текст джерела