Chemistry Commons^™

Development Of Forward Osmosis Based Separations: A Novel Approach In Membrane Technology, Yu-Hsuan Chiao

Graduate Theses and Dissertations

Tackling the worldwide severe water shortage, the membrane technology is considered to be the most efficient approach and hence, used widely as a cost-effective sustainable solution. “Forward osmosis (FO)” has been the major attention in recent time. FO uses osmotic pressure as the driving force to draw the water passing the membrane and achieve the desired separation performance. In general, it is considered to be a process with tremendous potential to resolve the present-day water shortage with extremely low energy consumption. However, the challenges of membrane and draw solution regeneration associated with FO processes must be conquered prior to their …

Conformational Polymorphism In Organic Crystals: Structural And Functional Aspects - A Review, Bidisha Sengupta, Pradeep K. Sengupta, Romans Grant1, Matthew Beasley1, Benjamin Mason1, Tanesha Love1, Larissa Barroso9, Mariela Alvarado9, M S. Zaman

Faculty Publications

Polymorphism in organic crystals involves the formation of isomeric molecular identities. It is dependent on the structural arrangement due to inter-atomic interactions, as well as external stimuli, which include temperature, visible and UV radiation. Conformational polymorphism of organic crystalline molecules is often the result of isomerism due to the twisting and turning of angular bonds. The arrangement of the atoms supports different types of bonding mechanisms (which include hydrogen bonding) within the same compound. This, in turn, results in the formation of cis/trans configurational isomers or a proton transfer species (tautomer), having different functional properties. The conformers support the flexibility …

Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener

International Conference on Durability of Concrete Structures

This work presents the results of an investigation carried out to assess durability of concrete made with a calcined clay- limestone-Portland cement with 47% of clinker, hereafter named LC3, produced during an industrial trial in 2013. LC3 was used to cast concrete blocks and later expose them at a natural location at the northern coast of Cuba. Reference concrete was cast with Cuban Portland cement having 88% of clinker. Throughout three years (2015, 2016, 2017) concrete cores were systematically taken and the specimens were subjected to a testing program that included Formation factor, chloride profiling, surface resistivity, air permeability and …

Hierarchical Nanostructuring Of Porous Silicon With Electrochemical And Regenerative Electroless Etching, Ermei Mäkilä, Anne-Mari Anton Willmore, Haibo Yu, Marianna Irri, Mark Aindow, Tambet Teesalu, Leigh Trevor Canham, Kurt W. Kolasinski, Jarno Salonen

Chemistry Faculty Publications

Hierarchically nanostructured silicon was produced by regenerative electroless etching (ReEtching) of Si powder made from pulverized anodized porous silicon. This material is characterized by ∼15 nm mesopores, into the walls of which tortuous 2–4 nm pores have been introduced. The walls are sufficiently narrow that they support quantum-confined crystallites that are photoluminescent. With suitable parameters, the ReEtching process also provides control over the emission color of the photoluminescence. Ball milling and hydrosilylation of this powder with undecylenic acid produces nanoparticles with hydrodynamic diameter of ∼220 nm that exhibit robust and bright luminescence that can be excited with either one ultraviolet/visible …

Three-Dimensional Porous Vn Octahedron Catalyst With High Electrocatalytic Efficiency Toward Hydrogen Evolution Reaction, Can Yin, Wei-Wei Fu, Ling Fang, Shi-Li You, Hui-Juan Zhang, Yu Wang

Journal of Electrochemistry

With the rapid development of China’s economy, the demand for energy is increasing, and environmental problems are becoming more and more serious. The development and utilization of highly-clean new energy fuel can effectively alleviate the energy crisis and environmental pollution. Nowadays, exploring high-efficiency, environment-friendly and low-cost catalysts remains the focus of research in the hydrogen evolution reaction (HER). In this research, firstly, we proposed a three-dimensional porous vanadium nitride (VN) with octahedral structure, which was prepared by a calcination treatment method. The VN catalyst showed a good electrocatalytic activity toward HER, involving a small overpotential of 94.0 mV at -10 …

Influences Of Morphology And Nitrogen Doping On The Electrocatalytic Characteristics For Oxygen Reduction Reaction Of Nio/Rgo, Dong Liang, Heng-Yi Fang, Shuo Yao, Jie-Mei Yu, Zhao-Liang Zhang, Zhan-Kun Jiang, Xue-Ping Gao, Tai-Zhong Huang

Journal of Electrochemistry

In this research, the reduced graphene oxide (rGO) supported sheet-like NiO (NiO/rGO) and spherical-like NiO (NiO/N-rGO) catalysts for oxygen reduction reaction (ORR) were prepared. The structures, morphologies and chemical states of the two catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical catalytic performance of the two catalysts for ORR were investigated by cyclic voltammetry (CV), Tafel, linear sweeping voltammetry (LSV), rotating disc electrode (RDE) and rotating ring disc electrode (RRDE) tests. Electrochemical results showed that the current density and onset potential (about 0.89 V) …

Preparation Of Nanostructural Mno-Porous Graphene Hybrid Material By Thermally-Driven Etching Of Mno For Lithium-Air Batteries, Juan Yang, Jun-Wei Lang, Peng Zhang, Bao Liu

Journal of Electrochemistry

In this paper, improving the surface morphology of graphene(GNSs) as designed concept. we describe a MnO/porous-graphene(MnO-PGNSs) was synthesized by a simple site-localized Mn²⁺ on GO (Mn-GO) by charge adsorption and then driving by high-temperature calcination, growing MnO nanoparticles and etching GNSs achieved on step. And Then focus on the key factors of influenced the etch hole formation are analyzed, founded the dispersion of Mn-GO; layer number of GO and calcination temperature also affected the formation of holes. In addition, the MnO-PGNSs as lithium-air battery cathode exhibits high reversible capacity compared with GNSs and PGNs and it is able to …

Investigations In Electrochemical Thermodynamic And Kinetic Properties Of As-Cast And As-Quenched Cemg10Ni2 Hydrogen Storage Alloys, Feng Hu, Li-Rong Luo, Yong-Zhi Li, Ting-Ting Zhai, Xin Zhao, Yang-Huan Zhang

Journal of Electrochemistry

In order to improve the electrochemical hydrogen storage properties of CeMg₁₀Ni₂ alloy, the rapid quenching technology was used to prepare CeMg₁₀Ni₂ alloys with nano-crystalline and amorphous structure. The microstructures of as-cast and as-spinning sample were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical hydrogen storage properties were investigated by an automatic galvanostatic charging/discharging, high rate discharging (HRD), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The results revealed that the as-cast alloy was composed of multiphase structures. The as-quenched alloys were made up of nano-crystalline and/or amorphous structures, and the …

Special Issue: Electrocatalysis And Fuel Cells, Shuangyin Wang

Journal of Electrochemistry

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A Facile Route To Synthesize Pt-Wo3 Nanosheets With Enhanced Electrochemical Performance For Her, Peng-Jie Jiang, Yi Lv, Chang-Miao Chen, Hong-Cheng He, Yong Cai, Ming Zhang

Journal of Electrochemistry

Platinum-tungsten trioxide (Pt-WO₃) nanosheets were synthesized on nickel foams (NFs) directly. As great conductive networks, NFs substrates could greatly improve the electrode performance of WO₃. The modified platinum nanoparticles not only enhanced the electron transformation of catalysts, but also increased the active sites for hydrogen evolution reaction (HER). Pt-WO₃/NF revealed a better catalytic activity than WO₃/NFs with a smaller Tafel slope (80 mV·dec^-1) and a lower overpotential of 72 mV at the current density of 10 mA·cm^-2. In addition, Pt-WO₃/NF showed great durability and stability during …

Nickel Selenide Derived From [Ni(En)3](Seo3) Complex For Efficient Electrocatalytic Overall Water Splitting, Dan-Dan Chen, Xue-Qing Gao, Hong-Fei Liu, Wei Zhang, Rui Cao

Journal of Electrochemistry

Electrocatalytic water splitting is considered as a promising technology for renewable energy. The development of efficient, stable, cost-effective, and bifunctional catalysts for both water reduction and oxidation has continued to face significant challenges. Herein, we report a robust and highly active nickel selenide (NiSe) spheres grown on carbon cloth (CC) by electrodeposition from a nickel selenite complex which is a single source containing both Ni and Se. A combination of two chemicals containing, separately, Ni and Se is used in traditional preparations of metal selenides, causing possible problems in the uniformity of the products. The as-prepared NiSe-EA/CC electrode exhibited electrocatalytic …

Pd Nanoparticles Supported On The Etched Ni Foams As High-Performance Electrocatalysts For Direct Ethanol Fuel Cells, Chi Zhang, Cheng-Fei Li, Gao-Ren Li

Journal of Electrochemistry

The development of non-Pt anode electrocatalysts with high activity and long-term durability at low cost for fuel cells still remains enormous challenge. Here we report the Pd nanoparticles supported on Ni foams etched by the mixed acids (HNO₃+H₂SO₄+H₃PO₄+CH₃COOH) (Pd/ME-NF) that are designed and fabricated as high-performance electrocatalysts for ethanol oxidation in alkaline media. Because of the advantages of large open space, fast electrolyte penetration/diffusion and rapid electron transfer process, the Pd/ME-NF catalysts exhibited significantly improved electrocatalytic activity and durability compared with the commercial Pd/C catalysts.

Ultrafast And Real-Time Dynamics Of Nanomaterials Studied By Advanced Spectroscopic Techniques, Jeewan Chaminda Ranasinghe

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are used to study excited-state dynamics and monitor real-time growth dynamics of different types of nanomaterials. In the first study, the growth dynamics of colloidal gold-silver core-shell nanoparticles are studied using in situ second harmonic generation and extinction spectroscopy. The growth lifetimes are studied under different reaction conditions, resulting in different silver shell thicknesses, with spectral comparisons to finite-difference time-domain calculations. The results are consistent with a three-step growth process. During the first step of the nanoparticle growth reaction, rough and uneven surfaces are formed rapidly giving rise to plasmonic hot spots with corresponding broad, red-shifted …

Minimalistic Peptide-Based Supramolecular Systems Relevant To The Chemical Origin Of Life, Daniela Kroiss

Dissertations, Theses, and Capstone Projects

All forms of life are based on biopolymers, which are made up of a selection of simple building blocks, such as amino acids, nucleotides, fatty acids and sugars. Their individual properties govern their interactions, giving rise to complex supramolecular structures with highly specialized functionality, including ligand recognition, catalysis and compartmentalization. In this thesis, we aim to answer the question whether short peptides could have acted as precursors of modern proteins during prebiotic evolution. Using a combination of experimental and computational techniques, we screened a large molecular search space for peptide sequences that are capable of forming supramolecular complexes with adenosine …

Synthesis And Characterization Of Multifunctional Transition Metal Oxide Nanoparticles Through A Modified Sol-Gel Method With Application In Energy Storage, Julien Lombardi

Dissertations, Theses, and Capstone Projects

The Synthesis of transition metal oxide nanoparticles has been studied in great detail over the many years. The most studied transition metal oxide nanoparticles are perovskites of the ABO₃ stoichiometry (A and B = transition metal) and more recently double perovskite crystal structures of the AA’BO₆ or A₂BB’O₆ stoichiometry due to the many different properties arising from the many different combinations of elements possible. These materials have proven potentially useful in many fields, but due to properties such as ferroelectricity and ferromagnetism, the desire to integrate these materials into electronics is ever growing. Many synthesis …

Probing The Gelation Phenomena In Molecular And Seed-Based Gels, Malick Samateh

Dissertations, Theses, and Capstone Projects

The interest in molecular gels has been gaining momentum as evident from being developed for a broad spectrum of applications. This impetus stems from several reasons that include: (i) molecular gels are highly stimuli responsive as they easily respond to thermodynamic changes, disintegrating into well-defined chemicals/building blocks because of the purely physical (in contrast to chemically cross-linked) nature of the interactions holding their 3D networks together; (ii) the sheer abundance of simple small molecules to choose starting materials from and the vast potential of tunability of the low molecular weight gelators (LMWGs) make the LMWGs and the molecular gels highly …

Preface To Special Issue Of Electrochemical Reduction Of Carbon Dioxide, Qing Li, Min Liu

Journal of Electrochemistry

No abstract provided.

Recent Progress In Copper-Based Catalysts For Electrochemical Co2 Reduction, Wen Lei, Wei-Ping Xiao, De-Li Wang

Journal of Electrochemistry

As the situation of energy crisis and environmental pollution become more and more serious, the electrochemical reduction of carbon dioxide (CO₂) has attracted lots of attention because of its multiple meanings such as environment, resources and economic benefits. In this paper, the state of the art electrochemical reduction of CO₂ in aqueous solution is reviewed, and the latest research progress in Cu-based catalysts with different structures and morphologies is summarized. In the end, the application prospects, opportunities and challenges of Cu-based materials are briefly presented to provide an outlook for future research directions.

Regulation Of Copper Surface Via Redox Reactions For Enhancing Carbon Dioxide Electroreduction, Bao-Hua Hang, Jin-Tao Zhang

Journal of Electrochemistry

A large-scale application of fossil fuels has led to excessive emission of carbon dioxide (CO₂), resulting in serious environmental issues. A promising path to reducing CO₂ emissions is recycling CO₂ into valuable chemicals and fuels through an electrochemical process. Herein, the redox reactions between copper (Cu) and ferric chloride (FeCl₃) have been utilized to regulate the Cu surface composition and structure, aimed to improve the electrocatalytic activity toward CO₂ reduction. Typically, a series of samples (named Cu-1h, Cu-2h, Cu-3h and Cu-4h) were prepared via the redox reactions for various time from 1 to …

Single-Layer Oxygen Deficiency Δ-Mno2 For Electrochemical Co2 Reduction, Yue-Feng Zhang, Jian-Jun Liu, Zeng-Xi Wei, Xin-Xin Tian, Jian-Min Ma

Journal of Electrochemistry

Manganese dioxide (MnO₂) has been widely used in catalysis. In addition, since the defect engineering can change the electronic properties of the catalyst, here we have systematically studied electrocatalytic carbon dioxide reduction reaction (CO₂RR) on δ-MnO₂ with and without oxygen deficiency, denoted as Ov-MnO₂ and MnO₂, respectively. We calculate the electronic properties and the intermediate of free energy for MnO₂ and Ov-MnO₂ with the help of spin-polarized density functional theory. By analyzing this result, we can find that the introduction of defects change the δ-MnO₂ from semiconducting properties to …

Statuses, Challenges And Strategies In The Development Of Low-Temperature Carbon Dioxide Electroreduction Technology, Xu-Rui Zhang, Xiao-Lin Shao, Jin Yi, Yu-Yu Liu, Jiu-Jun Zhang

Journal of Electrochemistry

Low-temperature carbon dioxide (CO₂) electrochemical reduction technology is a hotspot for research and development in recent years as a way to reduce the negative impact of CO₂ on the environment and to generate energy storage through converting electricity to low-carbon fuels. Although basic research on catalyst activity, product selectivity, and reaction mechanism has been widely reported, the design and practicality of catalytic stability and corresponding electrochemical reactor systems have not been given sufficient attention and systematic development.  In this paper, two important factors affecting the development of CO₂ electrochemical reduction technology in low temperature aqueous solution …

Copper-Based Compounds For Electrochemical Reduction Of Carbon Dioxide, Fan Yang, Pei-Lin Deng, You-Jia Han, Pan Jing, Bao-Yu Xia

Journal of Electrochemistry

The electrochemical reduction of carbon dioxide (CO₂) to useful chemicals and fuels has attracted enormous interest since the deteriorating global warming and energy shortage problems resulted from ever-increasing CO₂ emission. Designing efficient catalysts is of capital significance to realize the efficient and selective conversion of CO₂. Among various catalysts explored, copper-based compounds have promising potentials with acceptable efficiency for hydrocarbon production. Herein, recent advances on copper-based materials are summarized for electrochemical CO₂ conversion. We intend to include the dimensional structure, different forms (alloy, oxide) and molecular catalysts in copper-based catalysts. Moreover, the reaction mechanisms …

Recent Advances In Bismuth-Based Co2 Reduction Electrocatalysts, Rui Zhou, Na Han, Yan-Guang Li

Journal of Electrochemistry

Carbon dioxide (CO₂) is an economical, secure and sustainable carbon resource around us. Its effective capture and recycling have been the focus of our entire society. Using the electrochemical method, CO₂ can be reduced to different value-added chemicals or fuels. This approach not only would mitigate CO₂ accumulation in the atmosphere, but also would help alleviate our dependence on fossil fuel. In this article, the basic principle and process of electrochemical CO₂ reduction are first introduced. The recent development in bismuth-based catalysts for electrocatalytic CO₂ reduction is reviewed with an emphasis on their preparation, …

Electrocatalytic Reduction Of Carbon Dioxide To Carbon Monoxide Using Cobalt Nitride, Chen Ma, Peng-Fei Hou, Peng Kang

Journal of Electrochemistry

Electrocatalytic reduction of carbon dioxide (CO₂) is a promising method to alleviate global warming issues, although it still faces many challenges. Herein, we report cobalt nitride for electrocatalytic reduction of CO₂ to carbon monoxide (CO) in an aqueous electrolyte. A comparison of catalysts with different preparation temperatures and atmospheres suggests that nitrogen doping is critical to improve catalytic activity. For the most active catalyst of 700-Co_5.47N/C, the CO current density reached 9.78 mA·cm^-2 at potential of -0.7 V vs. RHE. In addition, the CO/H₂ ratio could be adjusted from 1:3 to 3:2 by …

Effect Of Morphology Of Fe-N Codoped Carbon Nanomaterial On Electrochemical Reduction Reactions, Er-Ling Li, Fa Yang, Ming-Bo Ruan, Ping Song, Wei-Lin Xu

Journal of Electrochemistry

Graphene nanosheets (GS) and carbon nanotubes have been considered as good catalysts candidates for applications in energy conversion and storage. However, hybrids of GS and carbon nanotubes are always formed in transition metal-based nitrogen-doped system, making the system quite complex for exploring the structure-activity relationship. To prepare the catalysts with desired species controllably, we try to adjust the outcomes with the effect of nitrogen on the growth of carbon nanotubes. In this work, a series of Fe-N co-doped carbon hybrid catalysts containing N-doped GS or hybrids of GS/bamboo carbon nanotubes (BCNTs) or BCNTs were obtained with one-step pyrolyzed method. To …

Electrochemical Detection Of 4-Nitrophenol Based On Glassy Carbon Electrode Modified By Tio2Nps/Rgo Composite, Lin-Na Jiu, Yong-Qiang Cheng

Journal of Electrochemistry

4-nitrophenol (4-NP) has become factitious pollution, and presented a serious threat to the nature and human health. It is necessary to develop a convenient and fast detection method. In this work, the glassy carbon electrode modified by titanium dioxide nanoparticles (TiO₂NPs)/reduced graphene oxide (RGO) composite as an electrochemical sensor was studied for the trace detection of 4-NP. The morphology of the composite was characterized by scanning electron microscopy (SEM). The homogeneous mixing of titanium dioxide nanoparticles and reduced graphene oxide increased the specific surface area of the composite, and facilitated the electrochemical reaction of 4-NP. The electrochemical characteristics …

Preparations And Electrocatalytic Properties Of Cu-Bipy-Btc-Derived Carbon-Based Catalyst For Oxygen Reduction Reaction, Li-Hua Zhang, Jun-Feng Chen, Wan-Tang Huang, Yong-You Hu, Jian-Hua Cheng, Yuan-Cai Chen

Journal of Electrochemistry

Efficient and low-cost oxygen reduction reaction (ORR) electrocatalyst plays a key role for fuel cells. In this paper, ORR active metal organic framework (MOF: Cu-bipy-BTC, bipy = 2,2?-bipyridine, BTC = 1,3,5-tricarboxylate) was prepared using hydrothermal method, and then carbon-based material MOF-800 was obtained from pyrolyzing Cu-bipy-BTC at 800 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption isotherm and X-ray photolectron spectroscopy (XPS) were used to characterize the morphologies and structures of the catalysts. Linear sweep voltammetry (LSV) and current-time curve (i-t) were adopted to evaluate the electrocatalytic properties of the catalysts. The results …

Triple Functionalization Of Titanium Aluminum Vanadium For Orthopedic Implant Applications, Ashley Blystone

Electronic Theses and Dissertations

Orthopedic implant surgeries are on the rise in the United States, with well over a million surgeries performed annually. Common materials used for these applications include titanium and its alloy, titanium aluminum vanadium (Ti-6Al-4V). Ti-6Al-4V is chosen for this application due to its mechanical strength and corrosion resistance. However, Ti-6Al-4V does not support osseointegration and is susceptible to bacterial colonization. Therefore, these implants suffer from aseptic loosening and infection, necessitating removal and replacement. Revision surgery and treatment is financially burdensome and taxing on the patient. Current approaches focus on modifying the surface of Ti-6Al-4V through a variety of means to …

Organic-Inorganic Hybrid Composites: Superhydrophobic Polymer Coatings With Photoreactive Perfluorinated Phthalocyanines, Abdul Azeez

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

We report partly fluorinated and silicon-based polymers that incorporate inorganic/organic materials capable of generating reactive oxygen species (ROS) using only visible light and air. Polyvinylidene fluoride (PVDF), which incorporated a known perfluorinated phthalocyanine photosensitizer, F₆₄PcZn, supported on silicon and titanium oxides was further modified via chemical surface roughening to exhibit enhanced hydrophobicity when used as a coating. Water contact angles as high as ~159° have been observed, vs. ~ 92° for the unmodified polymer. The polymer matrix, however, does not resist the ROS it produces as evidenced by spectroscopic and SEM data. A polysiloxane matrix was similarly …

The Development Of An Integrated Simulation Model On Understandings On The Interaction Between Electromagnetic Waves And Nanoparticles, Xiaojin Wang

Masters Theses & Specialist Projects

To investigate the interaction between nanoparticles and electromagnetic waves, a numerical simulation model based on FEM was built in this thesis. Numerical simulation is an important auxiliary research method besides experiments. The optical properties of nanoparticles consist of scattering, absorption, and extinction, and in the case of nanoparticle suspension, the transmission is also involved. This thesis addressed two typical applications based on the established model, one was regarding the nanofluids for solar energy harvesting, and the other was regarding the optical properties of atmospheric soot. In the case of the nanofluids solar energy harvesting, the established model provided a convenient …