Materials Chemistry Commons^™

Spontaneous Formation Of One-Dimensional Hydrogen Gas Hydrate In Carbon Nanotubes, Wenhui Zhao, Lu Wang, Jaeil Bai, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We present molecular dynamics simulation evidence of spontaneous formation of quasi-one-dimensional (Q1D) hydrogen gas hydrates within single-walled carbon nanotubes (SW-CNTs) of nanometer-sized diameter (1−1.3 nm) near ambient temperature. Contrary to conventional 3D gas hydrates in which the guest molecules are typically contained in individual and isolated cages in the host lattice, the guest H₂ molecules in the Q1D gas hydrates are contained within a 1D nanochannel in which the H₂ molecules form a molecule wire. In particular, we show that in the (15,0) zigzag SW-CNT, the hexagonal H₂ hydrate tends to form, with one H₂ molecule …

Polyaniline In Situ Grafted To Graphene Sheets, Erwin P. Enriquez, Elliard Roswell S. Yanza, Geoffrey Matthew C. Tan, Christine Joy Querebilo, Armando Somintac, Arnel Salvador

Chemistry Faculty Publications

Graphene is one of the most promising allotropes of carbon with wide applications in nanotechnology. Modification of graphene by chemical means can further expand its uses. Here, liquid-exfoliated graphene is functionalized with p-aminophenyl moiety using p-nitrophenyl diazonium salts which were diazotized in situ then reduced by tin(II) chloride. The aminophenyl-graphene thus produced is further modified to form polyaniline-graphene (PANI-GNH) by in situ oxidative graft polymerization of aniline using ammonium peroxydisulfate as oxidizing agent. The properties of the PANI-GNH were compared with polyaniline/graphene blends by Raman, infrared and UV-Visible spectroscopy, and cyclic voltammetry. Indeed, PANI-GNH registered different spectrochemical and electrochemical properties …

The Mechanism Of Galvanic/Metal-Assisted Etching Of Silicon, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Bubbles: A Review Of Their Relationship To The Formation Of Thin Films And Porous Materials, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

Characterizing The Antioxidant Capacity Of Gevalia Traditional Roast Coffee Based On Brew Method, Erica Mendoza

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Modified Seed Growth Of Iron Oxide Nanoparticles In Benzyl Alcohol: Magnetic Nanoparticles For Radio Frequency Hyperthermia Treatment Of Cancer, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles have received sustained interest for biomedical applications as synthetic approaches are continually developed for precise control of nanoparticle properties. This thesis presents an investigation of parameters in the benzyl alcohol synthesis of iron oxide nanoparticles. A modified seed growth method was designed for obtaining optimal nanoparticle properties for magnetic fluid hyperthermia. With a one or two addition process, iron oxide nanoparticles were produced with crystallite sizes ranging from 5-20 nm using only benzyl alcohol and iron precursor. The effects of reaction environment, temperature, concentration, and modified seed growth parameters were investigated to obtain precise control over properties …

Van Der Waals Trilayers And Superlattices: Modification Of Electronic Structures Of Mos2 By Intercalation, Ning Lu, Hongyan Guo, Lu Wang, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We perform a comprehensive first-principles study of the electronic properties of van der Waals (vdW) trilayers via intercalating a twodimensional (2D) monolayer (ML = BN, MoSe₂, WS₂, orWSe₂) between a MoS₂ bilayer to form various MoS₂/ML/MoS₂ sandwich trilayers. We find that the BN monolayer is themost effective sheet to decouple the interlayer vdW coupling of the MoS₂ bilayer, and the resulting sandwich trilayer can recover the electronic structures of the MoS₂ monolayer, particularly the direct-gap character. Further study of the MoS₂/BN superlattices confirms the effectiveness of …

Fabrication And Characterization Of High Surface Area Gold Electrodes, Madhura S. Damle

Theses and Dissertations

High surface area gold electrodes are very good substrates for biosensors, catalysis and drug delivery. Their performance is characterized by good sensitivity, low detection limit and high signal. As a result, extensive research is being carried out in this field using different approaches of fabrication to generate high surface area porous electrodes of different morphology, pore size and structure. The morphology of the electrodes can be changed based on whether the approach involves a template or not, types of metal deposition, method and time of dealloying etc. The deposition of metal can be carried out using various approaches such as …

Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana

Theses and Dissertations--Chemistry

Lithium-ion batteries (LIBs) are the most commonly used type of rechargeable batteries with a global market estimated at $11 billion, which is predicted to grow to $60 billion by 2020. The global commercialization of Li-ion batteries is impeded by issues such as poor cycle life (5000 cycles achieved in some LIBs) in high energy and power density applications because of the rising internal resistance due to aging and safety concerns such as overcharge which ultimately leads to thermal runaway and explosions. A battery’s performance mainly depends on external factors such as electrode thickness and degree of compacting, and the type …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Concern-Driven Integrated Toxicity Testing Strategies For Nanomaterials - Report Of The Nanosafety Cluster Working Group 10, Hugh Byrne, Agnes G. Oomen, Peter M.J. Bos, Teresa F. Fernandes, Kerstin Hund-Rinke, Diana Boraschi, Karin Aschberger, Stefania Gottardo, Frank Von Der Kammer, Dana Kühnel, Danail Hristozov, Antonio Marcomini, Lucia Migliore

Articles

Bringing together topic-related European Union-(EU)-funded projects, the so-called “NanoSafety Cluster” aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e. specific information needs for a given NM based on realistic exposure scenarios. Recognized concerns can be addressed in a set of tiers using standardized protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g. structure …

Synthesis And Characterization Of Coloumnar Mesophases Of Novel Substituted Dibenzanthracenes And Their Donor-Acceptor Mixtures, Katie M. Psutka

Theses and Dissertations (Comprehensive)

In this thesis, the synthesis and liquid crystalline properties of a series of novel dibenz[a,c]anthracenes are reported. Specifically, two dibenzanthracenecarboxylate derivatives were prepared and were found not to exhibit a mesophase. In contrast, a series of novel N-substituted dibenzanthracenedicarboximides was also synthesized and found to exhibit broad columnar temperature ranges. Several dibenzanthracenedicarboximides substituted with different alkyl chains on the nitrogen atom were prepared and their mesomorphic temperature ranges were characterized. In general, it was found that having a longer, more flexible alkyl chain on the nitrogen atom resulted in a broadening of the columnar temperature range via a lowering …

Synthesis And Characterization Of Sugar Based Low Molecular Weight Gelators And The Preparation Of Chiral Sulfinamides, Hari Prasad Reddy Mangunuru

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) have received considerable attention in the field of chemistry from last few decades. These compounds form self-assembled fibrous networks like micelles, cylindrical, sheets, fibers, layers and so on. The fibrous network entraps the solvent and forms gel, because of the self-assembly phenomenon and their demonstrated potential uses in a variety of areas, ranging from environmental to medicinal applications.

Sugars are good starting materials to synthesize the new class of LMWG's, because these are different from some expensive materials, these are natural products. We have synthesized and characterized the LMGS's based on D-glucose and D …

Photocatalytic Hydrogen Production From A Noble Metal Free System Based On A Water Soluble Porphyrin Derivative And A Cobaloxime Catalyst, Theodore Lazarides, Milan Delor, Igor V. Sazanovich, Theresa M. Mccormick, Irene Georgakaki, Georgios Charalambidis, Julia A. Weinstein, Athanassios G. Coutsolelos

Chemistry Faculty Publications and Presentations

A combination of noble-metal free components, a water soluble porphyrin photosensitizer zincmeso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride [ZnTMPyP⁴⁺]Cl₄ (1) with cobaloxime complex [Co^III(dmgH)₂(py)Cl] (2) as a catalyst, creates an efficient system for photochemical hydrogen production acting under visible light with 280 TONs. This is the first example of a water soluble porphyrin acting as a photosensitizer for cobaloxime catalysed H₂ production.

Ferroelectric Hexagonal And Rhombic Monolayer Ice Phases, Wen-Hui Zhao, Jaeil Bai, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Two new phases of water, the mid-density hexagonal monolayer ice and the high-density flat rhombic monolayer ice, are observed in our molecular dynamics simulations of monolayer water confined between two smooth hydrophobic walls. These are in addition to the two monolayer ices reported previously, namely, the low-density 4∙8² monolayer ice and the high-density puckered rhombic monolayer ice (HD-pRMI). Stabilities of the structures are confirmed by ab initio computation. Importantly, both new phases and the HD-pRMI are predicted to be ferroelectric. An in-plane external electric field can further stabilize these ferroelectric monolayer ices.

Mos2/Mx2 Heterobilayers: Bandgap Engineering Via Tensile Strain Or External Electrical Field, Ning Lu, Hongyan Guo, Lei Li, Jun Dai, Lu Wang, Wai-Ning Mei, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We have performed a comprehensive first-principles study of the electronic and magnetic properties of two-dimensional (2D) transition-metal dichalcogenide (TMD) heterobilayers MX₂/MoS₂ (M = Mo, Cr, W, Fe, V; X = S, Se). For M = Mo, Cr, W; X = S, Se, all heterobilayers show semiconducting characteristics with an indirect bandgap with the exception of the WSe2/MoS2 heterobilayer which retains the directbandgap character of the constituent monolayer. For M = Fe, V; X = S, Se, the MX₂/MoS₂ heterobilayers exhibit metallic characters. Particular attention of this study has been focused on engineering the bandgap …

Unraveling Crystalline Structure Of High-Pressure Phase Of Silicon Carbonate, Rulong Zhou, Bingyan Qu, Jun Dai, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Although CO₂ and SiO₂ both belong to group-IV oxides, they exhibit remarkably different bonding characteristics and phase behavior at ambient conditions. At room temperature, CO₂ is a gas, whereas SiO₂ is a covalent solid with rich polymorphs. A recent successful synthesis of the silicon-carbonate solid from the reaction between CO₂ and SiO₂ under high pressure [M. Santoro et al., Proc. Natl. Acad. Sci. U.S.A. 108, 7689 (2011)] has resolved a long-standing puzzle regarding whether a Si_xC_1−xO₂ compound between CO₂ and SiO₂ exists in nature. Nevertheless, the detailed …

A Photoelectron Spectroscopy And Ab Initio Study Of The Structures And Chemical Bonding Of The B25 − Cluster, Zachary A Piazza, Ivan H. Popov, Wei-Li Li, Rhitankar Pal, Xiao Cheng Zeng, Alexander I. Boldyrev, Lai-Sheng Wang

Xiao Cheng Zeng Publications

Photoelectron spectroscopy and ab initio calculations are used to investigate the structures and chemical bonding of the B₂₅ − cluster. Global minimum searches reveal a dense potential energy landscape with 13 quasi-planar structures within 10 kcal/mol at the CCSD(T)/6-311+G(d) level of theory. Three quasi-planar isomers (I, II, and III) are lowest in energy and nearly degenerate at the CCSD(T) level of theory, with II and III being 0.8 and 0.9 kcal/mol higher, respectively, whereas at two density functional levels of theory isomer III is the lowest in energy (8.4 kcal/mol more stable than I at PBE0/6-311+G(2df) level). Comparison with …

Localized Corrosion Behavior Of Sensitized 304 Stainless Steel By Scanning Reference Electrode Technique, Chen-Qing Ye, Rong-Gang Hu, Rui-Qing Hou, Xiao-Ping Wang, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Based on a home-built setup of scanning reference electrode technique, and combined with conventional electrochemical measurements, the localized corrosion behavior of sensitized 304 stainless steel (304ss) had been investigated in this work. The results showed that, the non-sensitized 304ss or 304ss sensitized at 550 oC was susceptible to pitting; while 304ss sensitized at 650 oC or 750 oC suffered severe intergranular corrosion in 10% FeCl3 solution.