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You searched for +publisher:"Clemson University" +contributor:("Dr. Shiou-Jyh Hwu"). Showing records 1 – 3 of 3 total matches.

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Clemson University

1. Campbell, McKenzie Louise. Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds.

Degree: PhD, Chemistry, 2016, Clemson University

The need for environmentally safe reagents for the promotion of organic transformations is critical in order to reduce hazardous waste and byproducts associated with industrial-scale chemical processes. We have developed two practical methods that obviate the need for harsh oxidative and toxic brominating reagents in electrophilic halogenation reactions. In our hands, a catalytic loading of the inexpensive, commercially available V2O5 (~$0.25/g) promotes the bromolactonization of a series of substituted alkenoic acids in isolated yields up to 97% by means of the in situ generation of bromenium (Br+) from bromide (Br−) at room temperature. This process obviates the need for molecular bromine (Br2), known for its potent toxicity and threat to the human nervous system, instead relying on the use of less toxic bromide salts, such as ammonium bromide (NH4Br). The oxidation of halides to halenium equivalents has previously relied on the use of harsh oxidants like lead acetate or Oxone®. The system used by our group is promoted by the mild organic oxidant, urea-hydrogen peroxide (UHP), thereby making this process more environmentally benign. The methodology can be extended to afford high yields of α-brominated β-diketones. Our group’s interest in vanadium catalysis through next turned to an investigation of polyoxometalates. Specifically, highly functional, anionic polyoxovanadates (POVs) developed in the Hwu laboratory posed a particular interest as possible catalysts for organic oxidations. A room temperature oxidation of alcohols using reduced polyoxovanadates Cs5(V14As8O42Cl) (III-2) and Cs11Na3(V15O36Cl)Cl5 (III-3) was explored. The selective oxidation of various substituted secondary benzylic alcohols were promoted in good to quantitative yields using only 2 mol % of catalyst III-2 in the presence of the terminal co-oxidant tert-butyl hydrogen peroxide (t-BuOOH). Further investigation has focused on kinetic studies of the transformation. In a separate focus area, our group, in collaboration with the Alexis laboratory developed the preparation of nanoparticles comprised of a Poly(D,L-lactic acid)-poly(ethylene glycol)-poly(ethyleneimine) (i.e. PDLLA-PEG-PEI) tri-block co-polymer. These nanoparticles are capable of selectively capturing environmental contaminants of broad concern bearing aldehyde and carboxylic acid functional groups in the gas phase. These materials effected greater than 80% and 76% reduction of aldehyde and carboxylic acid vapors, respectively, with reductions of up to 98% in some cases. Further, we demonstrated the functionalization of kaolinite and montmorillonite clays with PEI on a multi-gram scale using wet impregnation preparative methods. The synthesized amino-kaolinite clay revealed significant efficiency in capturing volatile aldehydes, carboxylic acids, and sulfides with most of these assays showing 100% reduction of these vapors. Future studies will focus on similar evaluation of the remediation capabilites, with the MMT and MMT-PEI clay minerals. Advisors/Committee Members: Dr. Daniel C. Whitehead, Committee Chair, Dr. Leah Casabianca, Dr. Shiou-Jyh Hwu, Dr. Modi Wetzler.

Subjects/Keywords: Chemistry

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APA (6th Edition):

Campbell, M. L. (2016). Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2404

Chicago Manual of Style (16th Edition):

Campbell, McKenzie Louise. “Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds.” 2016. Doctoral Dissertation, Clemson University. Accessed October 20, 2020. https://tigerprints.clemson.edu/all_dissertations/2404.

MLA Handbook (7th Edition):

Campbell, McKenzie Louise. “Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds.” 2016. Web. 20 Oct 2020.

Vancouver:

Campbell ML. Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds. [Internet] [Doctoral dissertation]. Clemson University; 2016. [cited 2020 Oct 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/2404.

Council of Science Editors:

Campbell ML. Investigating Materials that Promote New Organic Methodology and Remediation of Volatile Organic Compounds. [Doctoral Dissertation]. Clemson University; 2016. Available from: https://tigerprints.clemson.edu/all_dissertations/2404

2. Fulle, Kyle Raymond. Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks.

Degree: PhD, Chemistry, 2017, Clemson University

The crystal growth of large, defect-free and optically transparent materials has been an active area of research for over two centuries. A multitude of crystal growth techniques have been employed during this time, each submitting advantages and disadvantages to the solid-state community. As the heart of solid state lasers, communication devices and semiconductors, synthetically grown crystals for optical and magnetic applications hold the key for future innovation and design. There are large classes of materials that display recumbent characteristics that inhibit their manipulation by most current solid state techniques on the market. These refractory oxides display extreme melting ranges (> 2000 ⁰C), which inhibit solubility in the melt-based solid-state techniques typically engineered in crystal growth laboratories. Herein, this dissertation employs the high temperature and high pressure technique to drive the solubility of select refractory oxides into solution several hundred degrees prior to the melting point being attained. The investigation of pentavalent and tetravalent oxides (Nb2O5, Ta2O5, TiO2, GeO2, and SiO2) with rare-earth oxides (La - Lu, Sc) under hydrothermal conditions has led to the discovery of several new compounds previously unattainable by conventional solid-state growth techniques. These included, but are not limited to, RENbO4 (RE = La-Lu), La5Ti4O15(OH), Lu5Ti2O11(OH), and Ba2Lu2Si4O12F2 single crystals. The discovery of new classes of materials will lead to further investigation of optical properties. Furthermore, the ability to solubilize metal oxides, hundreds of degrees below their melting point, is leading to high-quality, defect-free, bulk single crystal growth of new and existing materials. As the solution chemistry of metal oxides continues to be investigated and explored under hydrothermal conditions, new optical and magnetic materials continue to emerge and display desirable traits in applied sciences. Advisors/Committee Members: Dr. Joseph W. Kolis, Committee Chair, Dr. Shiou-Jyh Hwu, Dr. William T. Pennington, Dr. Joseph S. Thrasher.

Subjects/Keywords: Bulk growth; Hydrothermal crystal growth; Optical materials; Rare-earth oxides; Refractory oxides; Solution growth

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Fulle, K. R. (2017). Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2068

Chicago Manual of Style (16th Edition):

Fulle, Kyle Raymond. “Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks.” 2017. Doctoral Dissertation, Clemson University. Accessed October 20, 2020. https://tigerprints.clemson.edu/all_dissertations/2068.

MLA Handbook (7th Edition):

Fulle, Kyle Raymond. “Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks.” 2017. Web. 20 Oct 2020.

Vancouver:

Fulle KR. Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks. [Internet] [Doctoral dissertation]. Clemson University; 2017. [cited 2020 Oct 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/2068.

Council of Science Editors:

Fulle KR. Exploratory Hydrothermal Synthesis and Crystal Growth of Refractory Rare-Earth Oxides with Tetravalent and Pentavalent Metal Oxide Building Blocks. [Doctoral Dissertation]. Clemson University; 2017. Available from: https://tigerprints.clemson.edu/all_dissertations/2068

3. Zhu, Jingyi. Defects in Graphene: Electrochemical, Magnetic, and Optical Properties.

Degree: PhD, Physics, 2016, Clemson University

Graphene has attracted tremendous attention due to its unique proper- ties, such as its two-dimensional structure, zero-band-gap, and linear dispersion relation of its electronic band structure, which are all very interesting from a fundamental standpoint. In addition, its ultra-light weight, high surface area, exceptional electrical and thermal conductivities, as well as robust mechanical strength portends huge potential in diverse applications. Defects in the otherwise perfectly hexagonal lattice of graphene lead to lattice symmetry breaking, and the emergence of new fundamental properties of graphene. Therefore, to understand the role of defects in graphene and further to control the fundamental characteristics of graphene through quantity and configuration of defects (or defect-engineering), it is essential to develop effective synthesis methods. This thesis describes such synthesis methods and the role of controlled defects on the electrochemical, magnetic, as well as the optical properties of graphene. Following the first two introductory Chapters, in Chapter 3 I describe the effects of vacancies and dopants on the electrochemical properties of graphene. Carbon is an excellent electrode material in high-energy and high-power density supercapacitors (SCs) due to its economic viability, high-surface area, and high stability. Although graphene has high theoretical surface area, and hence high double layer capacitance, the net amount of energy stored in graphene-SCs is much below the theoretical limits due to two inherent bottlenecks: i) their low quantum capacitance, and ii) limited ion-accessible surface area. We demonstrate that properly designed defects in graphene effectively mitigates these bottlenecks by drastically increasing the quantum capacitance and opening new channels to facilitate ion diffusion in the otherwise inaccessible interlayer gallery space in few layer graphene. Our results support the emergence of a new energy paradigm in SCs with 150% enhancement in double layer capacitance beyond the theoretical limit. Furthermore, we demonstrate defect engineering in graphene foams as an example of prototype bulk SCs with energy densities of 500% higher than the state-of-the-art commercial SCs without compromising the power density. Chapter 4 focuses on the magnetic properties of graphene when a dopant, such as a sulfur atom, is incorporated into the hexagonal framework of graphene. Bulk graphite is diamagnetic in nature, however, graphene is known to exhibit either a paramagnetic response or weak ferromagnetic ordering. Although many groups have attributed this magnetism in graphene to defects or presence of unintentional magnetic impurities, compelling evidence to pinpoint origin of magnetism in graphene was lacking. To address this issue, we systematically studied the influence of entropically necessary intrinsic defects (e.g., vacancies, edges) and extrinsic dopants (e.g., S-dopants) on the magnetic properties of graphene. We found that the saturation magnetization of graphene… Advisors/Committee Members: Dr. Apparao M. Rao, Committee Chair, Dr. Jian He, Dr. Shiou-Jyh Hwu, Dr. Mark E. Roberts.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zhu, J. (2016). Defects in Graphene: Electrochemical, Magnetic, and Optical Properties. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/1809

Chicago Manual of Style (16th Edition):

Zhu, Jingyi. “Defects in Graphene: Electrochemical, Magnetic, and Optical Properties.” 2016. Doctoral Dissertation, Clemson University. Accessed October 20, 2020. https://tigerprints.clemson.edu/all_dissertations/1809.

MLA Handbook (7th Edition):

Zhu, Jingyi. “Defects in Graphene: Electrochemical, Magnetic, and Optical Properties.” 2016. Web. 20 Oct 2020.

Vancouver:

Zhu J. Defects in Graphene: Electrochemical, Magnetic, and Optical Properties. [Internet] [Doctoral dissertation]. Clemson University; 2016. [cited 2020 Oct 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/1809.

Council of Science Editors:

Zhu J. Defects in Graphene: Electrochemical, Magnetic, and Optical Properties. [Doctoral Dissertation]. Clemson University; 2016. Available from: https://tigerprints.clemson.edu/all_dissertations/1809

.