Materials Chemistry Commons^™

Prospects Of D-Π-A Structured Porphyrins And Their Photoelectrochemical Application, Shuang-Shuang Liu, Jian-Feng Lu, Ming-Kui Wang

Journal of Electrochemistry

Porphyrins and their metalloderivatives are a class of compounds exhibiting a wide variety of interesting and highly useful properties, such as chlorophyll. Porphyrins are particularly interesting in photoelectrochemical applications due to their structural similarity to chlorophylls in natural photosynthetic systems, as well as their strong and tunable absorption properties. Recently, various porphyrins have been extensively studied for their applications in solar cells, photocatalytic hydrogen production, optical information storage and others. This review will focus on the unique physical and chemical properties of D-π-A structured porphyrins, and their photovoltaic performances in dye-sensitized solar cells. A brief discussion in the future development …

Fabrications Of Three Copper Sulfide Counter Electrodes And Their Influences On Photovoltaic Properties In Qdsscs, Xiao-Dan Hong, Zi-Jie Xu, Fa-Yin Zhang, Yu-Peng Li, Mei-Dan Ye, Chang-Jian Lin, Wen-Xi Guo

Journal of Electrochemistry

Quantum dot-sensitized solar cells (QDSSCs) have attracted intensive attention in scientific and industrial fields due to their high molar extinction coefficient, spectral tunability by particle size, ease of fabrication, and low cost. In the past years, semiconductor metal sulfides have attracted extensive attention because of their attractive physical and chemical properties for potential applications in many fields,such as PbS, CuS, CoS and CdS. In particular, copper sulfides have become a promising candidate for counter electrode materials in QDSSCs for their outstanding electrochemical and catalytic properties. In order to explore more stable and efficient copper sulfide counter electrode materials, in this …

Hydrothermal One-Step Synthesis Of Layered Nickel/Cobalt Double Hydroxide With Using Shape-Directing Agent And Homogeneous Precipitating Agent, Li-Wei Zhu, Yun-Hai Yan, Hui Jia, Run-Fen Liang

Journal of Electrochemistry

Nickel/cobalt double hydroxide (Ni/Co-DH) has been prepared by facile hydrothermal one-step synthesis method using hexamethylene tetramine (HMT) as a homogeneous precipitating agent and cetyltrimethylammonium bromide (CTAB) as a shape-directing agent. With the hydrolysis of HMT and the use of CTAB, the Ni/Co-DH could be synthesized without additional alkali source, and in the meantime, the Ni/Co-DH exhibited a controlled mesopore size of 13.4 nm and a large BET surface area of 93.6 m² •g^-1 . The X-ray diffraction (XRD) pattern displays that the Ni/Co-DH existed as a mixture of α-Ni(OH)₂-β-Co(OH)₂. The scanning electron microscope (SEM) …

Photoelectrochemical Water Splitting Cells: Methods For Improving Performance Of Electrodes And Recent Progress On Photocathodes, Kai-Jian Zhu, Wen-Jun Luo, Zhong-Jie Guan, Xin Wen, Zhi-Gang Zou, Wei Huang

Journal of Electrochemistry

Photoelectrochemical water splitting can convert solar energy into hydrogen which is an ideal way to utilize and store solar energy. A p-n tandem cell is considered as the most promising solar water splitting cell due to its high theory conversion efficiency, low cost and photoelectrode material flexibility. However, solar conversion efficiency of a tandem cell is still low in the experiment because of poor performance in a single photoelectrode. In this review, we have introduced some effective approaches to improve the performances of photoelectrodes by reducing recombination of photogenerated carriers in the bulk or on the surface, and suppressing back …

Theoretical Study Of Photoelectrochemical Reactions And Ec-Sers On Spr Metallic Electrodes Of Silver And Gold, Yuan-Fei Wu, Ran Pang, Meng Zhang, Jian-Zhang Zhou, Bin Ren, Zhong-Qun Tian, De-Yin Wu

Journal of Electrochemistry

At present photoelectrochemistry has received much concern back to nanostructures of noble metals from semiconductor electrodes. This is due to the surface plasmon resonance (SPR) effect of metallic nanostructures, which can effectively convert the far-field light to the near-field light and concentrate the photonic energy to the local surface area with high energy density. Thus, the different enhancement mechanisms, such as the local optical field enhancement, the formation of light generated hot carriers (hot electron-hole pairs), or the photothermal effect, have been proposed in literatures. On the basis of the SPR enhancement effect, the surface-enhanced Raman spectroscopy (SERS) can be …

Preparations And Photoelectrochemical Properties Of Phosphate Modified Rgo-Biobr Nanocomposites, Shuang-Ying Chen, Zhi-Jun Li, Xu-Liang Zhang, Kang Hu, Rui Yan, Li-Qiang Jing

Journal of Electrochemistry

The RGO-BiOBr nanocomposites have been successfully synthesized by a hydrothermal process, and then modified with phosphorous acids. The photoelectrochemical properties of the fabricated RGO-BiOBr nanocomposite films were studied. The results indicate that the photocurrent densities of RGO-BiOBr were much larger compared with those of the bare BiOBr, and interestingly, the photocurrent densities were further improved after phosphate modification. Based on the analyses of the produced hydroxyl radical amounts, the enhanced photocurrent densities could be attributed to the introduction of RGO and to the formed negative fields of modified phosphate groups, which are favorable for electrons to be transferred and for …

Solvent Effect On The Anticorrosive Properties And Active Coating Area Of A Long Alkyd Varnish, Saadawy M., Abd-El-Nabey B.A., Gomaa A.Z., Ashour M.

Journal of Electrochemistry

The effects of solvent nature and composition on the anticorrosive properties of a long alkyd varnish after different days of immersion in 0.5 mol•L^-1 NaCl were studied using electrochemical impedance spectroscopy. The protection efficiencies of the long alkyd varnishes containing different solvents increased with increasing the volatility of solvent or the composition of a given volatile solvent, which was confirmed with the observations using scanning electron microscopy and energy-dispersive X-Ray spectroscopy. The delaminated area, the area where the organic coating is detached from the metal surface leaving it unprotected, was found to decrease by increasing the volatility of solvent.

Activation Effect Of Nano-Carbon Derived From Co2 On Lead Electrode In Sulfuric Aqueous Solution, Yu-Qiao Song, Hua Zhu, Guang-Jin Zhao, Wen-Long Wu, Shou-Bin Zhou, Di-Hua Wang

Journal of Electrochemistry

Serious sulfation of the negative plate is one of the most popular reasons of the early failure of lead-acid battery. Addition of nano-carbon was proved to be effective for recovering the sulfated electrode and the property of the carbon material always plays an important role. In this work, a new kind of nano-carbon material with high electrical conductivity and good adsorption capability for heavy metal cations, which is electrochemically prepared from CO₂ in molten carbonates, was tested as activation additive for the sulfated lead electrode by cyclic voltammetry and SEM measurements. The results showed that the as-prepared carbon can …

WoX/Pedot:Pss Double-Layered Hole-Transport Layers For Efficient And Stable Planar Heterojunction Perovskite Solar Cells, Wen-Yuan Qiao, Qiang Guo, Cong Li, Shuang Ma, Fu-Zhi Wang, Song-Yuan Dai, Zhan-Ao Tan

Journal of Electrochemistry

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a commonly used hole-transport material in the perovskite solar cells (PerSCs) structure of perovskite/fullerene planer heterojunction, but it also has a negative effect on the stability of device because of its acidity which will corrode metal oxide transparent electrodes. In this work, a WO_x hole-transport layer with high work function was inserted into the PEDOT: PSS and FTO to enhance the stability and photovoltaic performance. The inserted WO_x layer not only can avoid direct contact between PEDOT:PSS and FTO, but also can further reduce the contact barrier between the electrode interface. We studied the effect …

A Novel Flexible Dye-Sensitized Solar Cell Based On Pt Networks Counter Electrode, Zi-Jie Xu, Fa-Yin Zhang, Xiao-Dan Hong, Wen-Xi Guo, Xiang-Yang Liu, Chang-Jian Lin

Journal of Electrochemistry

Flexible dye-sensitized solar cells (DSSCs) have received widespread attentions in recent years because of their ease of fabrication, low production cost, relatively high chemical stability and flexibility. We report the fabrication of ZnO DSSCs based on the highly flexible, conducting, catalytic and transparent Pt networks counter electrode, and the performance of this solar cell was characterized by SEM, XRD, polarized fluorescence microscope, motor, I-V test station and electrochemical workstation. Compared to Pt nanofiber arrays (NFs), Pt networks not only show a better conductivity, but also exhibit superior transparency and catalytic activity. Furthermore, Pt networks electrode could be constructed on arbitrary …

Discrimination Of Chiral Copper(Ii) Complexes Upon Binding Of Galactonoamidine Ligands, Susanne Striegler, Jessica Pickens

Chemistry & Biochemistry Faculty Publications and Presentations

The coordination between N-p-methylbenzyl-D-galactonoamidine, a putative transition state analogue of the hydrolyis of glycosidic bonds, and symmetric and chiral binuclear copper(II) complexes was characterized by spectroscopic titration, isothermal titration calorimetry, circular dichroism spectroscopy, and DFT calculations to elucidate the binding sites in the carbohydrate upon coordination to selected metal complexes. For the formation of metal complex-glyconoamidine assemblies, contributions of the amidine site and of the hydroxyl group at C-2 in the glycon of the amidine are noted. The chiral complexes S- and R-Cu2bpdbo are discriminated by a third binding site in the carbohydrate that leads to higher stability of complexes …

Engineering Nanoarchitectures From Nanosheets, Nanoscrolls, And Nanoparticles, Taha Rostamzadeh

LSU New Orleans Theses and Dissertations

The ability to encapsulate/insert different kinds of nanoparticles (NPs) in scrolled nanosheets (NSs) may lead to the formation of new nanocomposite materials that yield novel properties. These nanostructures resemble “peapods” that consist of NPs chains (“peas”) located in a hollow space of desired nanoscrolls (“pods”). Depending on different combinations of “peas” and “pods” diverse families of nanopeapods (NPPs) can be synthesized which may exhibit interesting properties not accessible from the individual components. Though there exist various synthetic methods for the formation of NPPs, more development in terms of simplicity, flexibility, and productivity of synthetic approaches are needed so that different …

Assembly Of Nucleic Acid-Based Nanoparticles By Gas-Liquid Segmented Flow Microfluidics, Matthew L. Capek, Ross Verheul, David H. Thompson

The Summer Undergraduate Research Fellowship (SURF) Symposium

The development of novel and efficient mixing methods is important for optimizing the efficiency of many biological and chemical processes. Tuning the physical and performance properties of nucleic acid-based nanoparticles is one such example known to be strongly affected by mixing efficiency. The characteristics of DNA nanoparticles (such as size, polydispersity, ζ-potential, and gel shift) are important to ensure their therapeutic potency, and new methods to optimize these characteristics are of significant importance to achieve the highest efficacy. In the present study, a simple segmented flow microfluidics system has been developed to augment mixing of pDNA/bPEI nanoparticles. This DNA and …

Density Functional Theory Based Electrolyte Design Formulation For Lithium-Sulfur Batteries, Cynthia Ly, Carolyn Sturges, Vijay Murugesan

STAR Program Research Presentations

Lithium-ion (Li-ion) batteries are commonly used in portable electronics such as cellphones and laptops. Most Li-ion batteries operate on intercalation principle with typical theoretical specific energy of 400-600 (Wh/Kg). There is great scientific interest in lithium-sulfur (Li-S) batteries as a possible successor of traditional Li-ion batteries because Li-S holds the potential of being a very powerful (1550 Wh/kg theoretical specific energy) yet very cost-efficient battery (due the abundance and inexpensiveness of sulfur). However, one major problem in Li-S battery research is the polysulfide “shuttle phenomenon”, which is the shuttling of polysulfide species due to the dissolution of sulfide from the …

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks are synthetic porous materials with great capacity for adsorption of carbon dioxide and methane. They chemically appear as a chain-link fence with nodes of metal connected by organic linkers. The pores between the nodes define the characteristics of the material, allowing gas particles of specific size to pass through while blocking larger particulates. While there has been success in synthesizing small amounts of metal organic frameworks, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. …

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …

Correlation Of Polymer Performance And Hansen Solubility Parameters, Daniel Jobse Mania

Master's Theses

Ready-to-use (RTU) grout is becoming more important to the finish and remodeling construction industry. Market research shows it is a fast-growing product that not only is creating its own space, but is beginning to supplant existing technology.

The original intent of this research was to investigate formulation parameters and how they affect grout performance. It was learned that particle size and oil absorption (OA) value are important filler properties that affect performance as much as adequate packing density and optimal pigment volume concentration (PVC) without going beyond critical PVC (CPVC).

Polymer architecture was also determined to be extremely important, but …

Mida Boronates Are Hydrolysed Fast And Slow By Two Different Mechanisms, Jorge A. Gonzalez, O. Maduka Ogba, Gregory F. Morehouse, Nicholas Rosson, Kendall N. Houk, Andrew G. Leach, Paul H.-Y. Cheong, Martin D. Burke, Guy C. Lloyd-Jones

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for building-block-based small molecule construction, largely due to the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, hindering efforts to address current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base-mediated and the other neutral. The former can proceed more than three orders of magnitude faster, and involves rate-limiting attack at a MIDA carbonyl carbon by hydroxide. The alternative ‘neutral’ hydrolysis …

Co7se8 Nanostructures As Catalysts For Oxygen Reduction Reaction With High Methanol Tolerance, Jahangir Masud, Manashi Nath

Chemistry Faculty Research & Creative Works

Co₇Se₈ nanostructures electrodeposited on glassy carbon (GC) electrodes show high efficiency for oxygen reduction reaction (ORR) with high methanol tolerance as compared to Pt electrocatalysts. In the presence of methanol, the onset potential for the ORR at Pt/GC is shifted from 0.931 V (vs reversible hydrogen electrode (RHE)) to 0.801 V (vs RHE), whereas it remains the same (0.811 V vs RHE) at Co₇Se₈/GC in the presence and absence of methanol in 0.5 M H₂SO₄ solution. The Co₇Se₈/GC electrodes also showed high cyclability in the presence …

Synthesis And Applications Of Lanthanide Sulfides And Oxides, Christopher Marin

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation focuses on two of the key fields where lanthanides find ready application: as optically active materials with a focus on the lanthanide sulfides, and as catalytic materials with a focus on cerium oxide.

The lanthanide sulfides have attracted considerable interest for their potential as solar energy conversion materials, pigments, infrared window materials, and phosphor host media. However, applications of these materials remain limited due to their synthetic difficulty along with their not well understood properties compounded by both their difficulty in manufacturing as well as in simulating largely due to the need to take into account f-shell electrons. …