Chemistry Commons^™

Fuel Cell Performance Of Non-Precious Metal Based Electrocatalysts, Yan-Feng Zhang, Fei Xiao, Guang-Yu Chen, Min-Hua Shao

Journal of Electrochemistry

The commercialization of proton exchange membrane fuel cells (PEMFCs) is hindered by high cost and low durability of Pt based electrocatalysts. Developing efficient and durable non-precious metal catalysts is a promising approach to addressing these conundrums. Among them, transition metals dispersed in a nitrogen (N)-doped carbon support (M-N-C) show good oxygen reduction reaction activity. This article reviews recent progress in M-N-C catalysts development, focusing on the catalysts design, membrane electrode assembly fabrication, fuel cell performance, and durability testing. Template-assisted approach is an efficient way to synthesize M-N-C materials with homogeneously dispersed single atom active site and reduced metal particles, carbides …

Electrochemical Energy Storage And Conversion Based On Organic Electrodes, Jian-Hang Huang, Xiao-Li Dong, Zhao-Wei Guo, Yuan-Yuan Ma, Yan-Rong Wang, Yong-Gang Wang

Journal of Electrochemistry

Aqueous batteries have been considered to be a competitive candidate for large-scale energy storage. However, most of aqueous batteries adopt inorganic electrode materials with metallic elements, which are based on the reversible insertion of metal ions, making their application being highly hindered by limited cycle life, environmental issue, high cost and low reserves. On the other hand, organic electrode materials offer the advantages of abundant reserves, tunable structures, renewability and environmental benignity. Furthermore, the wide internal space enables these organics to flexibly store various charge carriers. Organics have been investigated as the alternative to inorganic electrode materials. Herein, we review …

Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

The electrochemical conversion of CO₂ to chemical raw material for further utilization shows promising future to alleviate global warming and realize carbon cycle in nature, which is of great significance to the green chemistry and sustainable development. This review briefly introduces the advantages of CO₂ electrochemical reduction (CO₂ER) and its basic reaction principles, and summarizes the recent progress in a series of activity enhancement strategies based on nanosized metal catalysts. The influences of alloy effect, interface engineering, synergistic effect, surface defect engineering and support effect on the catalytic performance of nanosized metals for CO₂ER …

Response Of Photoluminescence Of H-Terminated And Hydrosilylated Porous Si Powders To Rinsing And Temperature, Kurt W. Kolasinski, Joseph D. Swanson, Benjamin Roe, Teresa Lee

Chemistry Faculty Publications

The photoluminescence (PL) response of porous Si has potential applications in a number of sensor and bioimaging techniques. However, many questions still remain regarding how to stabilize and enhance the PL signal, as well as how PL responds to environmental factors. Regenerative electroless etching (ReEtching) was used to produce photoluminescent porous Si directly from Si powder. As etched, the material was H-terminated. The intensity and peak wavelength were greatly aected by the rinsing protocol employed. The highest intensity and bluest PL were obtained when dilute HCl(aq) rinsing was followed by pentane wetting and vacuum oven drying. Roughly half of the …

Embedded Gold Nanoparticles For Metal Enhanced Photoluminescence, Hasna Alali

Dissertations

Noble metal nanoparticles (MNPs) have attracted great attention in electronics, solar cells and catalysis. Their unique optical properties and biocompatibility makes them useful in biological applications like imaging, drug delivery, therapy and diagnostic. At the surface of MNPs the collective oscillation of free electrons resonates with a particular wavelength of incident light, generating the Localized Surface Plasmons Resonance (LSPR). LSPR results in absorption and scattering of incident light. Scattering results in reflecting photons and absorption leads to enhanced photoluminescence and quenching of fluorophores, if the fluorophore is in the vicinity of MNPs.

Most of the studies in this regard have …

Doping Effects On Transition-Metal Silicides: Crystal Structures And Physical Properties Of Aluminium Doped Rhenium Silicide, Victoria Decocq

Graduate Theses/Dissertations

Semiconductive transition-metal silicides (e.g., ReSi) express weak thermoelectric properties. These properties can improve through n-type or p-type doping (e.g., Al), resulting in altered crystal structures. Binary rhenium silicide (ReSi_1.75) exhibits promising thermoelectric properties and an intriguing crystal structure. Previous research has shown ReSi_1.75 changes from a commensurate supercell MoSi₂-type structure to an incommensurate superspace group structure, when doped with aluminium to ReAl_0.074Si_1.67. ReSi_1.75 expresses a figure of merit (ZT) of 0.70 at 800°C, which improves to a ZT of 0.95 at 150°C for ReAl_0.02Si_1.75. Because of …

A Simple Predictive Model For Estimating Relative E-Cigarette Toxic Carbonyl Levels, Shawna Vreeke, Xijing Zhu, Robert Strongin

Chemistry Faculty Publications and Presentations

E-cigarette devices are wide ranging, leading to significant differences in levels of toxic carbonyls in their respective aerosols. Power can be a useful method in predicting relative toxin concentrations within the same device, but does not correlate well to inter-device levels. Herein, we have developed a simple mathematical model utilizing parameters of an e-cigarette’s coil and wick in order to predict relative levels of e-liquid solvent degradation. Model 1, which is coil length/(wick surface area*wraps), performed in the moderate-to-substantial range as a predictive tool (R² = 0.69). Twelve devices, spanning a range of coil and wick styles, were analyzed. …

Synthesis And Characterization Of Bimetallic Gold-Silver (Au-Ag) Nanocatalyst Via Seed Colloid Technique, Berahim Nurafaliana

Student Works (2020-2029)

In the present study, unique catalysts of monometallic gold (Au), silver (Ag) and bimetallic gold-silver (Au-Ag) nanoparticles (NPs) were prepared with different size or diameters by the citrate-thermal reduction and the seed colloidal techniques, respectively. The catalytic nanoparticles were characterized by various advanced analytical techniques such as Ultraviolet-visible spectroscopy (UV-vis), zeta potential, electron dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), High-angle annular dark-field (HAADF) scanning transmission-electron microscopy (STEM) imaging and the energy dispersive spectroscopy (EDS) elemental mapping. The catalytic performance of the nanoparticles were ascertained through the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in …

Synthesis And Characterization Of Self-Cleaning Hydrophobic Organic Coating, Abdul Jaafar Amirul Syafiq

Student Works (2020-2029)

Three self-cleaning coating systems namely Polydimethylsiloxane (PDMS)/Sylgard, PDMS/3-Aminopropyltriethoxysilane (APTES) (tagged as A1) and A1 blended with nano-Calcium Carbonate (CaCO3) have been synthesised on glass substrates via dip-coating and spray-coating techniques. All of the prepared coatings were dried under ambient condition before being subjected to characterisations and testing(s). The effect of various weight percentages of Sylgard resin that are 5wt.% (S1 coating), 10wt.% (S2 coating), 15wt.% (S3 coating), and 20 wt.% (S4 coating) on the hydrophobicity, self-cleaning property, anti-fog performance and mechanical property of PDMS/Sylgard coating have been discussed in the first section of this thesis. The PDMS/Sylgard coated glass substrates …

Synthesis Of Polyaniline Modified With Palm Oil Based Alkyd As Counter Electrode In Solar Cell Application, Ramli Mariam Fadzlina

Student Works (2020-2029)

Presently, shortage of sustainable and environmental friendly energy resources has become an important global concern. Dye-sensitized solar cell (DSSC) has widely been used as a clean energy conversion device that can solve this problem. Platinum (Pt) has commonly been used as counter electrode (CE) in DSSC due to its good redox property. However, Pt is expensive and could be easily corroded in tri-iodide solution. Recently, polyaniline (PAni) has shown promising performance in DSSC, but PAni exhibit poor adhesion on fluorine-doped tin oxide (FTO) substrate. In this study, an environmental friendly CE was developed by modifying PAni using titanium dioxide (TiO2) …

Microstructural Evolution And Mechanical Properties Of Ultra-Fine Grained Tubular Components Processed By Severe Plastic Deformation, Mesbah Mohsen

Student Works (2020-2029)

The lightweight alloys have been widely used in various engineering applications such as automotive, aerospace, construction, and biomedical industries due to their low densities, high ductility, formability, and facile machining. However, the emerging trend for materials with high mechanical strength and plasticity hampers the widespread application of these alloys. Over the last two decades, severe plastic deformation (SPD) has been introduced as a promising approach for enhancement of the mechanical performance of the lightweight alloys through microstructural manipulations and grain refinement. However, the SPD techniques have been extensively utilized for the fabrication of non-tubular geometries and the studies on the …

Mxenes As Flow Electrodes For Capacitive Deionization Of Wastewater, Naqsh E. Mansoor

Boise State University Theses and Dissertations

The energy-water nexus poses an integrated research challenge, while opening up an opportunity space for the development of energy efficient technologies for water remediation. Capacitive Deionization (CDI) is an upcoming reclamation technology that uses a small applied voltage applied across electrodes to electrophoretically remove dissolved ionic impurities from wastewater streams. Similar to a supercapacitor, the ions are stored in the electric double layer of the electrodes. Reversing the polarity of applied voltage enables recovery of the removed ionic impurities, allowing for recycling and reuse. Simultaneous materials recovery and water reclamation makes CDI energy efficient and resource conservative, with potential to …

Computational Elucidation Of The "Coloring Problem" In Rhenium Aluminum Silicon Compounds, Alec George Neeson

Graduate Theses/Dissertations

Re₁Si₁Al₁ and its related compounds are potential thermoelectric materials. Previously, it was reported to adopt a MoSi₂-type structure with Si and Al atoms statistically sharing the same crystallographic sites. This recent study indicates otherwise – Si and Al are segregated and occupy different sites when mixed with a 1:1:1 stoichiometry. To confirm and rationalize the segregation between Si and Al, this research studied this compound with first-principle calculations. Several model structures have been constructed for Re₁Si₁Al₁ including a number of different super-cell models. Energy analysis confirmed that the …

Development Of Plasticized Methylcellulosepotato Starch Blend Based Polymer Electrolytes For Protonic Cell And Supercapacitor Applications, Hamsan Muhamad Hafiz

Student Works (2020-2029)

In the current work, the preparation of the polymer electrolyte (PE) systems consists of methylcellulose-potato starch polymer matrix, ammonium nitrate (NH4NO3) as ionic source and glycerol as plasticizer are done by solution cast technique. X-ray diffraction (XRD) has shown that blend with 60 wt.% methylcellulose and 40 wt.% potato starch possesses the lowest degree of crystallinity. The possible interactions within the PE are verified using Fourier transform infrared (FTIR) spectroscopy. As the concentration of NH4NO3 is at 30 wt.%, the conductivity is optimized up to (4.37 ± 0.16) × 10-5 S cm-1 and then maximized to (1.26 ± 0.1) × …

Chemistry And Biochemistry Authored Faculty Publications: Snapshot Of The Ranking Of Journals In Which They Published Based On Data From Journal Citation Reports (Jcr), Lutishoor Salisbury, Yang Tian, Jeremy Smith

University Libraries Faculty Publications and Presentations

This report presents a snapshot of the research output of the Chemistry and Biochemistry Department at the University of Arkansas for the period 2015-2019. The contents of the report were generated using Web of Science Core Collection databases and the Journal Citation Report only. It highlights the journals in which the researchers published and the ranking of those journals.

Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo

Journal of Science Education for Students with Disabilities

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

Elucidating Collagen Degradation Synergy Between Col G And Col H From Hathewaya (Clostridium) Histolytica And Identifying Novel Structural Features In Hpt And Rec Domains From Vars Histidine Kinase In V. Alginolyticus, Perry Caviness

Graduate Theses and Dissertations

In this research the mechanisms by which Hathewaya (Clostridia) histolytica collagenases are secreted and work together to degrade collagens are investigated. While H. histolytica collagenases Col G and Col H have similar multi-domain structures the difference in number of and orientation of the domains hint that the two target different regions in collagen. Study small angle x-ray scattering (SAXS) was used to give a low-resolution envelope of full-length Col G and Col H and Col G/Col H non-catalytic domains bound to a collagen-like peptide (mini-collagen). SAXS derived envelopes along with structural information was used to tease out the mechanisms by …

Investigation Of The Structural, Electronic, And Thermoelectric Properties Of Mono- Chalcogenides, Aida Sheibani

Graduate Theses and Dissertations

The structural, electronic, and thermoelectric properties of GeTe are studied using density functional theory and Boltzmann transport equations. This material has a rhombohedral crystal structure in ambient temperature with a ferroelectric behavior due to lack of inversion symmetry. This study suggests that the presence of asymmetry in GeTe can lead to an improvement in the thermoelectric properties of this material. In addition, studies on introducing Group III, IV, and V dopants to GeSe show that while these impurities can improve the power factor and decrease the lattice thermal conductivity, they cannot enhance the figure of merit.

Thermotropic And Lyotropic Phase Behaviours Of Spontaneously Self-Assembled Amphiphilic Branched-Chain Glycosides With Various Chain Length, Abdul Hamid Hairul Amani

Student Works (2020-2029)

Lipid polymorphism is a process which illustrates the self-assembly of lipid aggregation depending on the environment. Lipids such as branched-chain glycolipids which are amphiphilic molecules also known as amphitropic tend to generate mesophases in thermotropic (dry) and lyotropic (solvation) conditions. These molecules are capable of self-aggregating into various types of glycolipid self-assemblies offering an interesting insight in relation to their functions in living cells. Hence, this study aims to investigate the mesophases of ꞵ-D-glycosides which are branched-chain synthetic glycolipids, namely, ꞵ-D-glucosides and ꞵ-D-maltosides. The study was carried out on the thermotropic phases of dry glycosides and the lyotropic phases of …

Microstructural Characteristics And Mechanical Properties Of Sn-Ag-Cu Solders With Minor Additions Of Al And Zn, Yee Mei Leong

Student Works (2020-2029)

Driven by the recent trend towards miniaturization of lead free electronic products, researchers are putting immense efforts to improve the properties and reliability of Sn based solders. Recently, much interest has been shown on low silver (Ag) content solder SAC 105 (Sn-1.0Ag-0.5Cu) solder because of economic reasons and improvement of impact resistance as compared to SAC387(Sn-3.8Ag-0.7Ag). The present work investigates the effect of minor (0.1-0.5wt.%) Aluminium (Al) and Zinc (Zn) addition to SAC105 on the bulk and interfacial structure between solder and copper substrate during reflow and after thermal aging , the mechanical properties of the solder joint and the …

Synthesis Of Polyurethane Incorporated By Calcium Oxide And Magnesium Oxide For Heavy Metal Removal From Water, Fard Mohsen Vafaei

Student Works (2020-2029)

Water contaminated by heavy metals such as copper, lead, nickel, and cadmium has significant adverse impacts on receiving water. In recent years, various methods, such as adsorption, chemical precipitation, and ion exchange, have been extensively studied for the elimination of heavy metals. Adsorption is one of the numerously and diversely reported mechanisms of removing heavy metals due to its simplicity and costeffectiveness. In this study, highly permeable rigid polyurethanes (PU) incorporating calcium oxide (CaO) (PU/CaO) composite materials were prepared via a facile and economic one-pot synthesis method and characterized for remediation of heavy metal from water. To investigate the effect …

The Influence Of Carbon Nanotubes And Mn Dopant Onto Zinc Oxide For Degradation Of Organic Pollutant Model Under Visible Light Irradiation, Ab Wahab Norfarhanah

Student Works (2020-2029)

Globally untreated industrial wastewaters are contaminating soil, surface water, groundwater, and consequently, the environment. Therefore, there is a huge interest in developing efficient and effective removal methods, such as photocatalytic advanced oxidation processes (AOP) under visible light (~47% of solar irradiation). In this work, the effectiveness of Mn-doped ZnO composite decorated onto multiwall carbon nanotubes (MWCNTs) on photodegrading organic pollutants was studied. This composite was simultaneously synthesized by sol gel method. XRD was used to confirm the formation of ZnO/Mn nanocomposite and the crystalline phase changes as ZnO content decreases when other elements were added to form the nanocomposite. The …

Nitrogen-Doped Graphene-Based Metal Composites For The Non-Enzymatic Detection Of Hydrogen Peroxide, Tajabadi Poor Mohammad Taghi

Student Works (2020-2029)

Recently, much attention has been devoted to detecting hydrogen peroxide (H2O2) because of its extensive range of applications in chemical synthesis, the textile industry, food production, fuel cell devices, and even in many oxidative biological reactions. Among the various methods of detection of H2O2, electrochemical sensors has many advantages, such as simplicity, high efficiency and sensitivity, as well as good selectivity., To improve the sensitivity of non-enzymatic sensors, noble metal nanoparticles with particular electrocatalytic activities can be utilized. The present research is aimed to design a hybrid approach for the development of novel nanostructures for non-enzymatic detection of H2O2. Herein, …

Understanding The Interfacial Reactions Initiating On Lithium Metal Surfaces In Next-Generation Battery Technologies, Joshua A. Lochala

Graduate Theses and Dissertations

Li-ion batteries have started to reach the theoretical maximum energy. Next-generation batteries represent the future of portable energy sources for vehicle electrification and grid energy storage. Li metal battery is one of the most promising next-generation battery technologies that could potentially double the cell-level energy of conventional Li-ion batteries. However, Li metal has multiple drawbacks that require addressing before realization. These drawbacks include dendrite formation leading to internal short and increasing internal resistance due to the breakdown of electrolyte, leading to rapid cell death. These problems stem from the interfacial reactions occurring during the plating and stripping of Li metal. …

Ensemble And Single Particle Studies Of Cation Exchange In Cuins2/Zns Qds And Their Application In Super-Resolution Imaging, Anh Tue Nguyen

Graduate Theses and Dissertations

Colloidal quantum dots (QDs) have great potential in many applications such as bioimaging, light emitting diodes, solar cells and lasers. However, a great number of studies have been focused on Cd based (II-VI) and Pb (IV-VI) based materials which are not suitable for mass production. Therefore, alternative types of QD containing less toxic materials have been introduced, including CuInS2 QDs. This I-III-VI semiconductor nanocrystals also attract lots of attention due to their large Stock shift, long fluorescence lifetime and high defect tolerance, making them attractive emitters for applications in bioimaging, photovoltaics and light emitting diodes.

In the first project, we …

Graphene Oxide Gold Nanostructure Based Surface Enhanced Raman Scattering Dna Biosensor For The Detection Of Meat Species, Khalil Md. Ibrahim

Student Works (2020-2029)

Authentication, detection and quantification of the ingredients, and adulterant in the food, meat and meat products are of high importance in current days. However, the conventional meat species detection techniques based on lipid, protein and DNA biomarkers have been confronting challenges due to the poor selectivity, sensitivity, and unsuitability for processed food products or complex food matrices. Hence, nanoparticle based DNA biosensing strategies have attracted the most interests and considered as one of the best alternatives to conventional strategies. Among these, surface enhanced Raman scattering (SERS) has gained the substantial acceptance as an excellent, fast and ultrasensitive sensing technique due …

Synthesis And In Vitro Studies Of Polycaprolactone-Coated Superparamagnetic Iron Oxide Nanoparticles For Magnetic Hyperthermia Therapy, Nasab Ziba Hedayat

Student Works (2020-2029)

Research has garnered a great interest in utilization of superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic nano-heating agents in hyperthermia cancer therapy by profiting from high apoptosis vulnerability of cancer cells at elevated temperatures. However, low oxidation resistance and high agglomeration tendency negatively affect magnetic characteristics of nanoparticles and subsequently their clinical efficiency. Particle surface modifications are potential approaches to endow SPIONs a range of desirable properties including high colloidal dispersity, low aggregation tendency, cytocompatibility, and high oxidation resistance. Currently, polymer coating has led to decrease magnetic hyperthermia efficiency through formation of intermediate layer between nanoheating agents and targeted cells. …

Development Of Nano Carbon And Conducting Polymers Based Ternary Composites For Supercapattery, Iqbal Javed

Student Works (2020-2029)

Although significant efforts have been devoted on the development of energy storage systems such as batteries and fuel cells in the past decades, the low power density, short cyclic life and high maintenance cost have kept them away from many applications. Alternatively, supercapattery which has the characteristic features of batteries as well as supercapacitors has gained much attention because of its rapid charge/discharge mechanism, long life cycle, and high power density. However, supercapattery generally suffers from poor energy density. This research aims to develop carbon and conducting polymers based ternary nanocomposites for high performance supercapattery. Pristine metal oxide nanostructures suffer …

The Interaction Of Ternary Components Of Ionic Liquid Gel Polymer Electrolytes For Lithium Metal Batteries, Xiao-Na Pan, Li-Lai Liu, Zhi-Pu Wang, Dan Wang, Yun Li, Pei-Xia Yang, Jin-Qiu Zhang, Mao-Zhong An

Journal of Electrochemistry

Ionically conductive gel polymer electrolyte is an excellent candidate due to its inflammable, nonvolatile and high thermal stability as compared to commercial liquid electrolytes which are usually flammable, volatile, and containing toxic organic solution as solvent, The synthesis and application of ionic gel polymer electrolytes in lithium ion/metal batteries have been previously reported. However, the interaction effects of N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) ionic liquid (as plasticizer) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on PVDF-HFP polymer remain unclear. In this work, the molecular structure of ionic liquid gel polymer electrolyte (ILGPE) composed of PP13TFSI, LiTFSI and PVDF-HFP was studied by Raman spectroscopy and Fourier-transform …

Electrochemical Oxidation Of Metal Chromium In Odium Hydroxide Aqueous Solution, Ping Han, Hai-Tao Feng, Ya-Ping Dong, Sen Tian, Bo Zhang, Wu Li

Journal of Electrochemistry

Ferrochrome electrolysis technology is a novel method for preparing sodium chromate (Na₂CrO₄). Although the method performs well at soft reaction conditions, controllable process, environmentally friendly production process, etc., the electrochemical oxidation process of metal chromium in NaOH aqueous electrolyte is still unclear. At present, there are few research articles about specific electrochemical oxidation of metal chromium in NaOH aqueous electrolyte. It is, therefore, meaningful to carry out the research in electrochemical oxidation mechanism of chromium. The electrochemical oxidation of metal chromium in 0.01 mol·L^-1 ~ 10 mol·L^-1 NaOH aqueous electrolytes at 20 °C was …