Inorganic Chemistry Commons^™

Complex Rare-Earth Antimonide Suboxides For Thermoelectric Applications, Peng Li Wang

Open Access Dissertations and Theses

Thermoelectric (TE) materials are able to convert heat directly into electricity and vice versa. This special property makes them valuable for a variety of applications involving power generation and refrigeration. In the search for potential high-performance TE materials, a number of rare-earth (RE) antimonide suboxide phases have been investigated.This presentation will focus on two classes of rare-earth antimonide suboxides: the RE₃Sb₃O₃ and RE₈Sb_3-dO₈ phases (C2/m space group) based on the RE–O frameworks and the anti-ThCr₂Si₂ type RE₂SbO₂ compounds ...

Synthesis Of Palladium-Based Electrocatalysis—From Pure Metal To Bimetallic Nanoparticles, Haijun Gao

Masters Theses

This thesis focuses on synthesis and characterization of palladium-based nanoparticles. Background information of the research in this thesis is provided in Chapter 1. Preparation and characterization of pure palladium nanoparticles are presented in Chapter 2. A fast and convenient method to prepare ultra small Pd nanoparticles via Pluronic P123 reduction is discussed in detail. Impregnation method and poly method are also studied in this chapter. Chapter 3 reports the studies of these methods to prepare ultra small bimetallic (bimetallic means a mixture of two metals) palladium-based nanoparticles. Oleylamine-mediated method used Pd nanoparticles prepared via P123 reduction as precursor. Ultra small ...

A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh C. Pillai

Articles

Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0 ...

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian W. Synnott, John Colreavy, Stephen Hinder

Articles

A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional ...

Novel Single-Site Titanosilicates With Targeted Connectivity And Nuclearity Of Titanium(Iv): Synthesis, Characterization And Catalytic Properties In Alkylphenol Oxidation, Nan Chen

Doctoral Dissertations

Titanosilicates are a family of porous materials that have shown excellent catalytic activity in olefin epoxidation and many other selective oxidation reactions. These materials have been extensively studied in the past few decades. One of the central questions in these investigations has been to define the catalytically active centers. The traditional synthesis of wet impregnation followed by calcination often produces more than one type of catalytic center within the same matrix, i.e. different coordination, connectivity and nuclearity. Each type potentially possesses unique catalytic activity. Co-existence of multiple catalytic centers makes it impossible to establish the relationship between the structure ...

The Synthesis And Characterization Of Novel Group 13 Nanostructured Building Block Heterogeneous Silicate Catalysts, Joshua G. Abbott

Doctoral Dissertations

A building block approach and sequential addition methodology were utilized to prepare heterogeneous silicate catalysts containing atomically dispersed group 13 metal (B, Al, Ga) centers. The octa(trimethyltin) silsequioxane, Si8[sub]O12[sub](OSnMe3[sub])8[sub], was used as the building block for the synthesis of these materials. Reaction of the building block with a variety of group 13 metal chlorides led to the formation of cross-linked matrices. All prepared materials were characterized by gravimetric analysis, gas absorption, IR, and NMR. In addition, aluminum and boron samples where characterized by 27[sup]Al and 11[sup]B solid state ...

Studies On Molecular Sieve Crystallization And Heteroatomic Substitution, Adam R. Macintosh

Electronic Thesis and Dissertation Repository

Molecular sieves have been scientifically and industrially important materials since their inception. These porous, crystalline networks of tetrahedrally coordinated atoms bridged by oxygen are known for their extremely high surface area and low density, making them excellent systems for catalysis. The framework of the AlPO₄ family of molecular sieves is itself non-catalytic, but through heteroatomic substitution these materials can diversify into the catalytically active silicoaluminophosphate (SAPO) and metalloaluminophosphate (MAPO) families of heterogeneous acid and redox catalysts. Research into the methods by which these substitutions occur, and the effects therein on the crystallization of the sieves, is of great importance ...

Nitrogen And Copper Doped Solar Light Active Tio2 Photocatalysts For Water Decontamination, Suresh Pillai, Donal Keane, John Colreavy

Articles

A novel class of photocatalytic coating capable of degrading bacterial and chemical contaminants in the presence of visible sunlight wavelengths was produced by depositing a stable photocatalytic TiO

2 film on the internal lumen of glass bottles via a sol–gel method. This coating was prepared in either undoped form or doped with nitrogen and/or copper to produce visible light-active TiO2 films which were annealed at 600 ◦C and were characterized by Raman and X-ray photoelectron spectroscopy. The presence of doped and undoped TiO2 films was found to accelerate the degradation of methylene blue in the presence of natural ...

Kinetics And Thermodynamics Of (1+2) Cycloadditions Of Transient Diphenylgermylene With Alkenes, Yaser Saeidi Hayeniaz

Open Access Dissertations and Theses

1,1-Dimethyl-3-phenyl-1-germacyclopent-3-ene (32) was synthesized and it was used for the study of the reactivity of diphenylgermylene (GePh₂) toward alkenes using steady state and nanosecond laser flash photolysis technique (nLFP) in hexanes solution.

The reactivity of GePh₂ toward several alkenes including 1-hexene, cis-2-hexene, trans- 3-hexene, cyclopentene, cyclohexene, cis-cyclooctene, methylcyclohexene, 2-methyl-2- pentene, 2-methyl-1-pentene and trans-3-methyl-2-pentene has been investigated by nLFP method. In all cases, the equilibrium constant was measured and it was found that there is a direct correlation between the Gibbs free energy of the reaction (∆G_r) and the ionization potential (IP) of the involved alkene. This ...

Synthesis, Structural And Magnetic Properties Of Rare-Earth Intermetallic Compounds, Yan Yin Janice Cheung

Open Access Dissertations and Theses

Series of rare-earth intermetallic compounds were synthesized and studied.

The Gd₄Ge_3-xPn_x (Pn = P, Sb, Bi; x = 0.5 - 3) series of compounds were synthesized to explore the stability of the non-existent Gd₄Ge₃ binary through partial Pn substitutions to increase valence electron concentrations. Electronic band structure calculations were performed to elucidate the relationships between the hypothetical "Gd₄Ge₃" and Gd₅Ge₄ binaries. All Gd₄Ge_3-xPn_x phases order ferromagnetically with relatively high Curie temperatures of 234 to 356 K.

The Gd₅Ge_{4- ...}

Investigations Of Zeolite Growth By Atomic Force Microscopy (Afm), Donghan Chen

Electronic Thesis and Dissertation Repository

Zeolites are microporous materials that have been used extensively in various fields. A better understanding on their crystallization process is important for their investigations. Atomic force microscopy (AFM) is a powerful tool for studying the growing traces on the crystal surface, providing information regarding the relation between surface events and framework structure. This thesis mainly focuses on the surface investigation of several zeolites and microporous materials. ZSM-11 single crystals were synthesized under hydrothermal conditions, and their crystallization process was monitored by AFM, PXRD, SEM, and SSNMR. SAPO-34 prepared under both HTS and DGC conditions showed morphological differences that are related ...

Reactions Of Platinum Complexes With Dimethylamine-Borane, Shawn M. Robinson

Electronic Thesis and Dissertation Repository

This thesis describes a study of the reactions of platinum complexes with dimethylamine-borane (DMAB) as models for alkane activation. It is concluded that sigma-borane complexes of platinum(II) or platinum(IV) will be difficult to synthesize or even to detect as intermediates in hydride transfer from boranes to platinum.

The complex [PtMe(O₂CCF₃)(bpy)] reacts with DMAB to form an intermediate [PtMeH(bpy)] complex, which undergoes reductive elimination of methane with further degradation to give platinum(0) and free 2,2’-bipyridine. The addition of methyl acrylate to the reaction allowed the trapping of the platinum-hydride, producing ...

Ionothermal Synthesis Of High Silica Zeolites In Deep Eutectic Solvents (Des), Zheng Sonia Lin

Electronic Thesis and Dissertation Repository

Phase-pure high silica zeolites have been synthesized using different deep eutectic solvents for the first time. ZSM-5 was made in tetrapropylammonium bromide/pentaerythritol. The reaction is affected by the amounts of seeding, water content, and organic structure-directing agent (SDA). Sodalite and ZSM-39 were prepared in tetramethylammonium chloride (TMACl)/1, 6-hexanediol by using the mineralizing agents NaOH and NH₄F, respectively. In urea/choline chloride, ZSM-5, Beta, ZSM-39, and ZSM-11 were made by using different organic SDAs in the presence of fluoride. The reaction temperature and the choice of organic SDA affect the type of structures being produced.

The crystallization ...

Reactivity Of Dimethylplatinum(Ii) Complexes With Peroxides, Kyle R. Pellarin

Electronic Thesis and Dissertation Repository

This thesis describes a study of dimethylplatinum(II) complexes containing bidentate nitrogen donor ligands. This work deals with the oxidative addition of peroxides and focuses on synthesis, characterization and reaction mechanisms of these complexes.

Dimethylplatinum(II) complexes were reacted with oxidants dimethyldioxirane (DMDO), meta-chloroperbenzoic acid (m-CPBA) and phthaloyl peroxide. The use of these oxidants has allowed for the synthesis of novel platinum(IV) complexes by oxidative addition and the formation of unique supramolecular networks. The formation of both trans- and cis-oxidative addition products was controlled by the type of oxidant utilized. By varying the ligand design of ...

The Synthesis And Reactivity Of New Pnictogen(Iii) Cations, Allison L. Brazeau

Electronic Thesis and Dissertation Repository

Chelating nitrogen based ligands are well known for their use with transition metals while their chemistry with p-block elements has been relatively underdeveloped. This thesis examines the structure, bonding and reactivity of group 15 elements supported by a pyridyl tethered 1,2-bis(imino)acenaphthene (“clamshell”) and various homo- and heteroleptic guanidinate frameworks.

The unique “clamshell” ligand contains a pendant Lewis base and has been used to support N-heterocyclic phosphenium and arsenium cations. Reactivity studies with the phosphorus analogue demonstrate the ability of the ligand to act as a Lewis base, while the phosphorus centre provides a Lewis acidic site ...