Chemistry Commons^™

Recent Process In Transition-Metal-Oxide Based Catalysts For Oxygen Reduction Reaction, Yao Wang, Zi-Dong Wei

Journal of Electrochemistry

Transition metal oxides (TMOs) based catalysts have become the most promising catalysts to be employed in anion exchange membrane fuel cell for the sluggish oxygen reduction reaction (ORR). However, their ORR activity is still far from that of the Pt-based catalysts. Therefore, it is important to develop high performance TMO based catalysts. Electrical conductivity and intrinsic activity have been regarded as the two keys to affect the ORR activity of the TMOs based catalysts. In this review, we focused on the recent progresses in the fundamental viewpoints on the electrical conductivity and intrinsic activity of the TMOs based ORR catalysts. …

Conference Information, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Preparation Of Nanoprobes And Their Possible Applications In Nanoscale Scanning Electrochemical Microscopy For Studying Electrocatalytic Oxygen And Hydrogen Reactions, Xing-Xing Chen

Journal of Electrochemistry

Scanning electrochemical microscopy (SECM) is a type of scanning probe microscopy, which can not only provide the topographical information, but also offer the electrochemical properties of different samples. The interrelationship of physical and electrochemical properties of a sample can be searched at a high-resolution scale due to the introduction of ultramicroelectrode (UME). With the continuous development of modern nanotechnology, the SECM probe has been improved with drastically decreasing its size down to nanometer. Meanwhile, to evaluate and understand the electrochemical performance of various electrocatalysts for both oxygen and hydrogen reactions with high-efficiency is highly demanded in the research area of …

Recent Advances In Continuous Models Of Electrochemical Supercapacitors, Hao-Tian Lu, Jing-Hong Zhou, Guang-Hua Ye, Xing-Gui Zhou

Journal of Electrochemistry

Electrochemical capacitors (supercapacitors) have been developed as a new type of energy storage device with high energy and power densities, which have the advantages of both fast charging-discharging as traditional capacitors and high energy density as batteries. Notable improvements in their electrochemical performance have been achieved in recent years owing to the recent advances in understanding of charge storage mechanisms and the development of advanced nanostructured materials. Recently, modeling and simulation of these supercapacitors has been applied as a useful approach to better understand the working mechanisms of the supercapacitors by describing the concentrations and electric fields inside the capacitors. …

Recent Advances In Non-Noble Metal Nanomaterials For Oxygen Evolution Electrocatalysis, Dan-Dan Zhao, Nan Zhang, Ling-Zheng Bu, Qi Shao, Xiao-Qing Huang

Journal of Electrochemistry

Hydrogen is a kind of renewable energies with the merits of environmentally friendly, abundance and high weight energy density, which can replace the fossil energy. The electrolysis of water is regarded as the most effective way to generate hydrogen. Owing to the sluggish kinetics and large overpotential of the anode oxygen evolution reaction (OER), the efficiency of the cathode hydrogen evolution reaction is greatly limited. Therefore, it is highly desirable to explore efficient, stable and low cost electrocatalysts to reduce the overpotential of OER and improve the efficiency of hydrogen evolution. Based on the natural characteristics of non-noble metal catalysts …

Preface For The Special Issue Of The Award Winners, Shi-Gang Sun

Journal of Electrochemistry

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Research Progresses In Improvement For Low Temperature Performance Of Lithium-Ion Batteries, Yue-Ru Gu, Wei-Min Zhao, Chang-Hu Su, Chuan-Jun Luo, Zhong-Ru Zhang, Xu-Jin Xue, Yong Yang

Journal of Electrochemistry

Lithium-ion batteries (LIBs) have become a new research hotspot due to their high energy density and long service life. However, the temperature characteristics, especially the poor performance at low temperatures, have seriously limited their wider applications. In this report, the research progresses in the low temperature performance of LIBs are reviewed. The main existing limitations of LIBs at low temperatures were systematically analyzed, and followed by discussion on the recent improvements in low temperature performances by developing novel cathode, electrolyte, and anode materials. The developments for improving the low temperature performance of LIBs are prospected. The three most important factors …

An Investigation On The Structure Of Au(111)/Imidazolium-Based Ionic Liquid Interface: Effect Of Alkyl Side Chain Length, Li Chen, Shuai Liu, Mian-Gang Li, Jian-Jia Su, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

In this work, we comparatively investigated the interfacial structures at Au(111) electrode surfaces in two ionic liquids (ILs) with different alkyl chain lengths by combining AFM force curve technique and electrochemical methods. The number and stability of the layering structures, and their potential-dependency were analyzed. The experimental results indicated that the tendencies of force-potential curves in the two ILs behave the same way. At potentials close to PZC, the ions arrange loosely, which lowers the stability of the layering structure. As the potential shifting away from PZC, more ions attach to electrode surface, which increases the stability of layering structure, …

Synthesis Of Keggin Polyoxometalates Modified Carbon Paste Electrode As A Sensor For Dopamine Detection, Peng-Fei Dong, Na Li, Hai-Yan Zhao, Min Cui, Cong Zhang, Ju-Jie Ren, Xue-Ping Ji

Journal of Electrochemistry

Polyoxometalates, a class of anionic clusters with structure diversity and size variability, make them very attractive in many fields such as electrochemistry, catalysis and medicine. The Co(C₁₅N₆H₁₂)₂[PW₁₂O₃₈]·5H₂O(Co[PW₁₂O₃₈]) modified carbon paste electrode was prepared in this work, and its electrochemical performances as the sensor for dopamine detection were characterized with electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The preparation conditions and test conditions were optimized respectively. Under the optimized conditions, the POMs modified carbon paste electrode exhibited good selectivity and sensitivity …

Effects Of Sulfur-Containing Additive On Low Temperature Performance Of Graphite Anode, Ze-Li Wu, Ye-Zhen Zheng, Zhong-Ru Zhang, Yong Yang

Journal of Electrochemistry

The low temperature performance of lithium ion battery mainly depends on the graphite anode, and one of the research focuses is to improve the low temperature performance of the anode by additives. In this paper, the effects of different sulfur-containing functional groups such as DTD (ethylene sulfate), 1,3-PS (1,3-propane sultone) and ES (ethylene sulfite) on low temperature performances of artificial graphite materials were systematically studied. The results in density functional theory (DFT) calculations, cyclic voltammetry (CV), scanning electron microscopy (SEM) and charge-discharge measurement clearly demonstrated that all three sulfur-containing additives could participate in formation of films on the surface of …

Electrodeposition Of Cobalt From Eutectic-Based Ionic Liquid, Rostom Ali M., Sankar Saha S, Ziaur Rahman Md

Journal of Electrochemistry

The electrodeposition of cobalt from a solution containing cobalt chloride in either a urea-choline chloride based or an ethylene glycol (EG)-choline chloride based ionic liquid has been carried out onto copper and steel cathodes by constant current and constant potential methods at different temperatures. The influences of various experimental conditions on electrodeposition and morphology of the deposited layers have been investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD)technique. It has been shown that the smooth, shiny with good adherence and bright metallic coloured cobalt coatings were obtained from both urea and EG based ionic liquids at the applied …

Electrochemical Deposition Of Cr From Cr(Iii)-Based [Bmim]Hso4 And Naoac Electrolyte, De-Ying Liu, Wei Luo, Wen-Juan Zhang, Shuo-Zhen Hu, Heng Xu, Xin-Sheng Zhang

Journal of Electrochemistry

Using trivalent chromium ions (Cr(III)) as the chromium source for chromium electrodeposition has attracted much attention since it can reduce the toxicity of the whole process. Even though the chromium deposition in Cr(III)-based ionic liquid bath can avoid the most hydrogen evolution problem, CrCl₃·6H₂O is widely used as the Cr(III) precursor, which still contains water and has the stable octahedral structure. As a result, it is difficult to deposit Cr and there is still hydrogen evolution reaction (HER). Moreover, the hydroxyl ions (OH^-) produced during HER react with Cr³⁺ to form Cr(OH)_{3 …}

The New Application Of Battery-Electrode Reaction: Decoupled Hydrogen Production In Water Electrolysis, Yuan-Yuan Ma, Zhao-Wei Guo, Yong-Gang Wang, Yong-Yao Xia

Journal of Electrochemistry

Hydrogen has been considered as a promising alternative to unsustainable fossil fuels because of its high calorific value, clean and abundant resources. Water electrolysis combined with renewable energy is regarded as the best way for hydrogen production, which will become the foundation of future hydrogen economy. For the past few years, many efforts have been employed to develop the cheap and high-performance catalyst for hydrogen evolution reaction and oxygen evolution reaction. However,the coupled hydrogen and oxygen evolution and the use of the expensive membrane have greatly restricted the flexibility of the conventional water electrolysis, and hindered the utilization of renewable …

Design Strategies Toward Highly Active Electrocatalysts For Oxygen Evolution Reaction, Tang Tang, Wen-Jie Jiang, Shuai Niu, Jin-Song Hu

Journal of Electrochemistry

Electrocatalytic water splitting is pivotal for efficient and economical production of hydrogen and oxygen gasses. However, the efficiency of the whole device is largely limited by the oxygen evolution reaction (OER) at the anode due to its sluggish kinetics. Thus, it is imperative to develop inexpensive, highly active OER catalysts to lower the reaction barriers. By examining the underlying critical factors for OER performance, this review outlines general principles for designing efficient nanosized OER catalysts, including (1) enhancing the intrinsic activity of active site by electronic modulation, crystallinity modulation, phase control, defect engineering and spin state engineering; (2) designing appropriate …

Recent Progress In Organic Redox Flow Batteries, Li-Xing Xia, Hao Liu, Lin Liu, Zhan-Ao Tan

Journal of Electrochemistry

Redox flow batteries (RFBs) are promising candidate for balancing instability of grids caused by integration of intermittent renewable energies such as solar energy and wind energy. Along with wide deployments in solar energy and wind energy due to abundance and declining installation cost, it can be predicted that RFBs will enter a period of rapid development. Basically,RFBs are electrochemical energy storage devices that decouple energy and power of the system by storing liquid electrolyte in tanks outside battery system itself. Such a unique framework makes RFBs flexible and fulfills the various demands of grids. During battery operation, redox-active species are …

About Antioxidant Activity Of Some Representatives Of Flora Of The Fergana Valley, К.А. Zahidov, S.D. Aronbaev, G.M. Abilkasimova

Scientific Journal of Samarkand University

The article presents the results of the determination of the antioxidant activity of aqueous and alcoholic extracts of 18 medicinal plants growing in the Fergana Valley using an electrochemical analyzer Σ - AOA. A solution containing 0.005 M K3 [Fe (CN) 6] and 0.001M K4 [Fe (CN) 6] in 0.05 M phosphate buffer with a pH of 6.86 was used as an electrochemically reversible mediator system. The standard of antioxidant activity was an aqueous and alcoholic solut ion of ascorbic acid with a known concentration. It was shown that all of the studied plants possess antioxidant activity to some extent. …

Molten-Salt Synthesis Of Complex Metal Oxide Nanoparticles, Jose P. Zuniga, Maya Abdou, Santosh K. Gupta, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we …

Primary Emissions Of Glyoxal And Methylglyoxal From Laboratory Measurements Of Open Biomass Burning, Kyle J. Zarzana, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, William P. Dubé, Robert J. Yokelson, Carsten Warneke, Joost A. De Gouw, James M. Roberts, Steven S. Brown

Chemistry and Biochemistry Faculty Publications

We report the emissions of glyoxal and methylglyoxal from the open burning of biomass during the NOAA-led 2016 FIREX intensive at the Fire Sciences Laboratory in Missoula, MT. Both compounds were measured using cavity-enhanced spectroscopy, which is both more sensitive and more selective than methods previously used to determine emissions of these two compounds. A total of 75 burns were conducted, using 33 different fuels in 8 different categories, providing a far more comprehensive dataset for emissions than was previously available. Measurements of methylglyoxal using our instrument suffer from spectral interferences from several other species, and the values reported here …

From The River To The Gulf: An Investigation Of Biogeochemical Cycling In Wetland Soils And Coastal Shelf Sediments, Katie Bowes

LSU Master's Theses

Louisiana is home to 40% of the coastal wetlands in the lower 48 states, yet accounts for 80% of the coastal wetland loss in this region. This loss is attributed to decreased sediment supply, levee alteration, sea level rise, channelization, and subsidence. The levee system in Louisiana disconnected coastal wetlands from the main stem of the Mississippi River (MSR), reducing the amount of land-building sediment that reaches coastal wetlands. This disconnection also allows a greater percentage of river discharge, including agricultural contaminants and runoff, to flow into the northern Gulf of Mexico (NGOM).

The 2012 Coastal Master Plan proposed eight …

A Redox Conjugated Polymer-Based All-Solid-State Reference Electrode, Ke Qu, Mingxi Fang, Shuwei Zhang, Haiying Liu, Xiangqun Zeng

Department of Chemistry Publications

This work reports the design, synthesis, and characterization of a novel redox-active conjugated polyaniline containing quinone moiety as a solid state reference electrode. The union of electro-active quinone with π-conjugated polyaniline was created by the first chemical synthesis of para-dimethoxybenzene-functionalized aniline as a monomer using a palladium-mediated coupling. The successful polymerization of the as-prepared monomer was accomplished without acid additives. Its post-polymerization modification with strong Lewis acid boron tribromide furnished unique poly (aniline quinone/hydroquinone) with desired properties for all-solid-state reference electrode (RE) applications. The electrochemical responses from the conjugated polyaniline backbone in this unique polymer have been “suppressed” by the …

Starch Synthesis In Ostreococcus Tauri: The Starch-Binding Domains Of Starch Synthase Iii-B Are Essential For Catalytic Activity, Julieta Barchiesi, Maria Belen Velazquez, Nicolas Palopoli, Alberto A. Iglesias, Diego F. Gomez-Casati, Miguel A. Ballicora, Maria Victoria Busi

Chemistry: Faculty Publications and Other Works

Starch is the major energy storage carbohydrate in photosynthetic eukaryotes. Several enzymes are involved in building highly organized semi-crystalline starch granules, including starch-synthase III (SSIII), which is widely conserved in photosynthetic organisms. This enzyme catalyzes the extension of the α-1,4 glucan chain and plays a regulatory role in the synthesis of starch. Interestingly, unlike most plants, the unicellular green alga Ostreococcus tauri has three SSIII isoforms. In the present study, we describe the structure and function of OsttaSSIII-B, which has a similar modular organization to SSIII in higher plants, comprising three putative starch-binding domains (SBDs) at the N-terminal region and …

Magnetic Ordering In A Vanadium-Organic Coordination Polymer Using A Pyrrolo[2,3-D:5,4-D']Bis(Thiazole)-Based Ligand, Yulia A. Getmanenko, Christopher S. Mullins, Vladimir N. Nesterov, Stephanie Lake, Chad Risko, Ezekiel Johnston-Halperin

Chemistry Faculty Publications

Here we present the synthesis and characterization of a hybrid vanadium-organic coordination polymer with robust magnetic order, a Curie temperature T_C of ∼110 K, a coercive field of ∼5 Oe at 5 K, and a maximum mass magnetization of about half that of the benchmark ferrimagnetic vanadium(tetracyanoethylene)_~2 (V·(TCNE)_~2). This material was prepared using a new tetracyano-substituted quinoidal organic small molecule 7 based on a tricyclic heterocycle 4-hexyl-4H-pyrrolo[2,3-d:5,4-d′]bis(thiazole) (C₆-PBTz). Single crystal X-ray diffraction of the 2,6-diiodo derivative of the parent C₆-PBTz, showed a disordered hexyl chain and …

Evaluating The Extent Of A Large-Scale Transformation In Gateway Science Courses, Rebecca L. Matz, Cori L. Fata-Hartley, Lynmarie A. Posey, James T. Laverty, Sonia M. Underwood, Justin H. Carmel, Deborah Herrington, Ryan L. Stowe, Marcos D. Caballero, Diane Ebert-May, Melanie M. Cooper

Peer Reviewed Articles

We evaluate the impact of an institutional effort to transform undergraduate science courses using an approach based on course assessments. The approach is guided by A Framework for K-12 Science Education and focuses on scientific and engineering practices, crosscutting concepts, and core ideas, together called three-dimensional learning. To evaluate the extent of change, we applied the Three-dimensional Learning Assessment Protocol to 4 years of chemistry, physics, and biology course exams. Changes in exams differed by discipline and even by course, apparently depending on an interplay between departmental culture, course organization, and perceived course ownership, demonstrating the complex nature of transformation …

Eddy Flux Measurements Of Sulfur Dioxide Deposition To The Sea Surface, Jack G. Porter, Warren J. De Bruyn, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Deposition to the sea surface is a major atmospheric loss pathway for many important trace gases, such as sulfur dioxide (SO2). The air–sea transfer of SO2 is controlled entirely on the atmospheric side of the air–sea interface due to high effective solubility and other physical– chemical properties. There have been few direct field measurements of such fluxes due to the challenges associated with making fast-response measurements of highly soluble trace gases at very low ambient levels. In this study, we report direct eddy covariance air–sea flux measurements of SO2, sensible heat, water vapor, and momentum. The measurements were made over …

Calculation Guided Rational Design And Synthesis Of Novel Cationic Fluorescent Meso–Pyridinium Bodipys For Bio-Imaging, Daniel J. Lamaster

LSU Doctoral Dissertations

Chapter 1 contains a brief overview of the history, synthesis, and properties of BODIPY dyes as well as that of the biomedical applications of bio-imaging and photodynamic therapy. Additionally, an overview of the theoretical framework of density functional theory and its time-dependent variant are provided. In Chapter 2, the effects of structural modification on the electronic structure and electron dynamics of cationic meso-(4-pyridyl)-BODIPYs were investigated. A library of 2,6-difunctionalized meso-(4-pyridyl)-BODIPYs bearing various electron-withdrawing substituents was designed and DFT calculations were used to model the redox properties, while TDDFT was used to determine the effects of functionalization on the excited …

Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky

LSU Doctoral Dissertations

Pesticides used in the United States must undergo registration by the United States Environmental Protection Agency (USEPA), after a multitude of analyses ranging from environmental fate to aquatic toxicological impacts to human risk exposure. Testing varies for each chemical, some requiring more testing than others. In many cases, environmental factors are restricted in the analysis of chemical behavior and organismal testing is limited to larvae. Many pesticides are formulated to breakdown in the environment by means of photolysis, hydrolysis, or oxidation, either to ensure low-persistence, limited transport, or to form the active ingredient (pro-pesticides). Environmental influences on chemical behaviors include …

A Near-Infrared Fluorescent Probe Based On A Fret Rhodamine Donor Linked To A Cyanine Acceptor For Sensitive Detection Of Intracellular Ph Alternations, Yibin Zhang, Jianheng Bi, Shuai Xia, Wafa Mazi, Shulin Wan, Logan Mikesell, Rudy Luck, Haiying Liu

Department of Chemistry Publications

A fluorescence resonance energy transfer (FRET)-based near-infrared fluorescent probe (B⁺) for double-checked sensitive detection of intracellular pH changes has been synthesized by binding a near-infrared rhodamine donor to a near-infrared cyanine acceptor through robust C-N bonds via a nucleophilic substitution reaction. To demonstrate the double-checked advantages of probe B⁺, a near-infrared probe (A) was also prepared by modification of a near-infrared rhodamine dye with ethylenediamine to produce a closed spirolactam residue. Under basic conditions, probe B⁺ shows only weak fluorescence from the cyanine acceptor while probe A displays nonfluorescence due to retention of the closed …

Metallo-Polyelectrolytes As A Class Of Ionic Macromolecules For Functional Materials, Tianyu Zhu, Ye Sha, Jing Yan, Parasmani Pageni, Md Anisur Rahman, Yi Yan, Chuanbing Tang

Faculty Publications

The fields of soft polymers and macromolecular sciences have enjoyed a unique combination of metals and organic frameworks in the name of metallopolymers or organometallic polymers. When metallopolymers carry charged groups, they form a class of metal-containing polyelectrolytes or metallo-polyelectrolytes. This review identifies the unique properties and functions of metallo-polyelectrolytes compared with conventional organo-polyelectrolytes, in the hope of shedding light on the formation of functional materials with intriguing applications and potential benefits. It concludes with a critical perspective on the challenges and hurdles for metallo-polyelectrolytes, especially experimental quantitative analysis and theoretical modeling of ionic binding.

Liquid Phenothiazine Catholytes For Non-Aqueous Redox Flow Batteries, Susan A. Odom, Matthew D. Casselman, Aman Preet Kaur

Chemistry Faculty Patents

Highly soluble, liquid phenothiazines containing methoxy-terminated ether and oligoether substituents are disclosed with high diffusion coefficients and robust performance in electrochemical measurements, which can be synthesized in one step from commercially-available starting materials, thereby circumventing previous synthetic limitations.

On The Roles Of Wheat Endosperm Adp-Glucose Pyrophosphorylase Subunits, Danisa M. L. Ferrero, Matias D. Asencion Diez, Misty L. Kuhn, Christine A. Falaschetti, Claudia V. Piattoni, Alberto A. Iglesias, Miguel A. Ballicora

Chemistry: Faculty Publications and Other Works

The ADP-glucose pyrophosphorylase from wheat endosperm controls starch synthesis in seeds and has unique regulatory properties compared to others from this family. It comprises two types of subunits, but despite its importance little is known about their roles. Here, we synthesized de novo the wheat endosperm ADP-glucose pyrophosphorylase small (S) and large (L) subunit genes, heterologously expressed them in Escherichia coli, and kinetically characterized the recombinant proteins. To understand their distinct roles, we co-expressed them with well characterized subunits from the potato tuber enzyme to obtain hybrids with one S subunit from one source and an L subunit from …