Chemical Engineering Commons^™

Perovskite Thin Films Annealed In Supercritical Fluids For Efficient Solar Cells, Gilbert Annohene

Theses and Dissertations

In the field of photovoltaics, scientists and researchers are working fervently to produce a combination of efficient, stable, low cost and scalable devices. Methylammonium lead trihalide perovskite has attracted intense interest due to its high photovoltaic performance, low cost, and ease of manufacture. Their high absorption coefficient, tunable bandgap, low-temperature processing, and abundant elemental constituent provide innumerable advantages over other thin film absorber materials. Since the perovskite film is the most important in the device, morphology, crystallization, compositional and interface engineering have been explored to boost its performance and stability. High temperatures necessary for crystallization of organic-inorganic hybrid perovskite films …

Development Of Novel Polymeric Materials For Their Application In Monitoring And Remediation Of Environmental Pollutants, Rishabh Shah

Theses and Dissertations--Chemical and Materials Engineering

Remediation of environmental pollutants from water is one of the major challenges in the 21st century. Utilizing novel polymeric materials to accomplish this challenge has garnered a lot of interest in recent times. Flexibility in synthesizing as well as functionalizing makes them attractive for their application in pollutant remediation. This work is based on development and characterization of novel crosslinked polymeric as well as linear polymeric materials from biphenyl-based monomers, biphenyl based crosslinker and a temperature responsive monomer (Nisopropylacrylamide (NIPAAm)) for their application in remediation of toxic pollutants such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and iron oxide nanoparticle …

Ultrafast Thermal Modification Of Strong Coupling In An Organic Microcavity, Bin Liu, Vinod M. Menon, Matthew Y. Sfeir

Publications and Research

There is growing interest in using strongly coupled organic microcavities to tune molecular dynamics, including the electronic and vibrational properties of molecules. However, very little attention has been paid to the utility of cavity polaritons as sensors for out-of-equilibrium phenomena, including thermal excitations. Here, we demonstrate that non-resonant infrared excitation of an organic microcavity system induces a transient response in the visible spectral range near the cavity polariton resonances. We show how these optical responses can be understood in terms of ultrafast heating of electrons in the metal cavity mirror, which modifies the effective refractive index and subsequently the strong …

Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song

Journal of Electrochemistry

Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt_0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 ^oC. The average diameter of the resultant Ru@Pt_0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of …

The Varied Thermal Response Of Magnetic Iron-Oxide Nanoparticles During Induction Heating In Liquid And Solid-Liquid Phase Change Mediums, Joshua Tompkins

Graduate Theses and Dissertations

This study investigates the induction heating response of uncapped iron oxide nanoparticles sonically dispersed as a nanofluid and mechanically distributed in solid phase change materials. The nanoparticles examined have a mean diameter of 14.42 nm and are magnetically heated in an alternating magnetic field at an amplitude of 72.6 kA/m at frequencies of 217, 303, and 397 kHz. Nanoparticle characterization was undertaken through transition electron microscopy, x-ray diffraction, and dynamic light scattering when in suspension. Carrier fluids were characterized through viscosity, heat capacity, and density measurements which were used in the calorimetric calculation of the specific absorption rate (SAR) of …

Modulating Mechanical Properties Of Polymer Composites Via Colloidal Particle Reinforcement, Yusheng Guo

LSU Master's Theses

Additive manufacturing allows the rapid process of complex objects with excellent design flexibility. However, the products often exhibit poor mechanical properties when pure polymer is applied as printable material. In this work, we demonstrate that printability of polymer can be dramatically improved when particle filler is added to form reinforced polymer composites. Furthermore, the interaction between filler and polymer matrix leads to the enhancement in mechanical properties of the printed product. The material reinforcement induced by addition of fillers enables the wide application of polymer composites to print structures with unique features. In the printing of silica-reinforced pNIPAM composite, we …

Synthesis And Characterization Of Silver Nanoparticles In Lamellar Lyotropic Liquid Crystal, Siti Mariah Mohd Yasin

Student Works (2020-2029)

Lamellar lyotropic liquid crystal-silver nanoparticles (LLLC-AgNPs) are synthesized using the in-situ method. The polarizer microscope showed a mosaic-like pattern with fan shape textures. The high resolution transmission electron microscope (HRTEM) confirmed that the AgNPs are spherical in shape with 4 – 12 nm size. Differential scanning calorimetry (DSC) determined the LLLC-AgNPs transition anisotropic phase to the highly ordered isotropic phase at 300 °C, and crystallinity was completed at 350 °C. Thermogravimetric analysis (TGA) verified that the LLLC-AgNPs were completely decomposed at 700 °C. Ultra-violet visible spectroscopy (UV-vis) found the absorption peaks at around 400 nm and proved that the AgNPs …

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 …

Optimization Of Nitrate Removal From Aqueous Solution By Acid-Activated Rice Straw Supported Nano Zero-Valent Iron Using Response Surface Methodology, Dalia A. Ali Eng, Nagwa Mahmoud Al-Mansi Prof, Mohamed Amin Sadek Prof., Ahmad Wafiq Abolnasr Dr.

Chemical Engineering

Rice straw is one of the most common agricultural wastes due to its large production amounts. Energy valorization of rice straw is a technology used for nitrate removal as the produced ashes used to generate the adsorbent by means of an alkali dissolution followed by acid precipitation. The novelty of the proposed process is that the production of the nano zero-valent iron supported acid-activated rice straw (AARS-nZVI) adsorbent is carried out without the energy valorization process but, through an acid activation for rice straw followed by precipitation of nZVI particles on its surface. The new adsorbent synthesis, characterization and application …

Growth Of Small Particles In Nonequilibrium Plasmas, Necip Berker Üner

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nonequilibrium plasma (NEP) is an extraordinary environment for material synthesis. NEP is comprised of hot electrons with temperatures greater than 10000 K and of cold ions and neutrals that are usually at few hundred kelvins above room temperature. Due to this large difference in species’ temperatures, the assumption of local thermal equilibrium does not hold in NEP. Therefore, NEP can act as a unique processor of mass, and it can transform materials along pathways that are not accessible by methods wherein local thermal equilibrium is valid. For decades, NEPs have been employed in the semiconductor industry to manufacture many thin …

Synthesis, Self-Assembly And High-Pressure Properties Of Nanoparticles And Hybrid Nanocomposites, Lingyao Meng

Nanoscience and Microsystems ETDs

Nanoparticles have gained significant scientific interests owing to their unique structural dimensions, size- and shape-tunable properties, and numerous fascinating applications, from opto-electronics, sensor devices, to energy, environmental, and medical fields. Furthermore, the synergistic integration of other materials, including organic polymers, with nanoparticles provides new opportunities and strategies to obtain nanocomposites with superior properties and functionalities. While there is already significant research on the synthesis and characterizations of nanoparticles and hybrid nanocomposites, some research questions, such as how to design and control the interfacial morphology in polymer/nanoparticle hybrid nanocomposites, how to synthesize metal- organic framework (MOF) nanoparticles in well-defined and uniform …

Preparations Of Nano-MnoX/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Cyclohexane Using Intermittent Electrodeposition, Xue Zhou, Hong Wang, Zhen Yin, Yu-Jun Zhang, Jian-Xin Li

Journal of Electrochemistry

Cyclohexanone and cyclohexanol (KA oil) obtained from highly selective oxidation of cyclohexane (CHA) show important industrial value and application prospects. In this work, the intermittent electrodeposition was developed to prepare nano-MnO_x catalyst loading porous tubular titanium membrane electrode (MnO_x/Ti), which was employed to constitute an electro-catalytic membrane reactor (ECMR) for the oxidation of cyclohexane to produce cyclohexanol and cyclohexanone. The surface morphology, crystal structure and electrochemical property of the catalysts were characterized by FESEM, XRD and electrochemical workstation, respectively. The results show that the catalyst prepared by the intermittent electrodeposition displayed nano-flower-like γ-MnO₂. Compared with …

Synthesis And Raman Study Of Hollow Core-Shell Ni1.2Co0.8P@N-C As An Anode Material For Sodium-Ion Batteries, Jia-Hui Chen, Xiao-Bin Zhong, Chao He, Xiao-Xiao Wang, Qing-Chi Xu, Jian-Feng Li

Journal of Electrochemistry

With the increasing demand for large-scale energy storage, great progress has been made in discovering new advanced energy storage materials. Sodium-ion batteries (SIBs) have attracted much attention in recent years due to their use of abundant sodium resources and their comparable electrochemical capacity to lithium-ion batteries (LIBs). In this paper, we developed novel hollow core-shell Ni-Co bimetallic phosphide nanocubes with N-doped carbon coatings (Ni_1.2Co_0.8P@N-C) as the anode material for SIBs. The material was synthesized through a low-temperature phosphorization method using resorcinol formaldehyde (RF) resin coating with a Ni-Co Prussian blue analogue (PBA) as a template and …

The Artificial Leaf: An Investigation Into The Sociotechnical Integration Of New Solar Energy Innovations, Alexandra K. Treml, Jamie M. Mears

Senior Honors Projects, 2020-current

Increasing global demand, combined with the volatility of fossil fuels, has called for a large-scale increase in renewable energy production. Photovoltaics hold significant potential, but by nature, solar energy is intermittent and lacks dispatchability. Researchers around the world are working to create innovative solutions that utilize semiconductors found in solar cell technologies in new ways. This project harnesses photoelectrochemical water-splitting, which uses light energy to dissociate water molecules into hydrogen and oxygen. When the water-splitting device is submerged in saltwater and illuminated by sunlight, oxygen and hydrogen gas are produced on opposite surfaces, and can be either released or stored …

Nio@Rgo Supported Palladium And Silver Nanoparticles As Electrocatalysts For Oxygen Reduction Reaction, Shuo Yao, Tai-Zhong Huang, Rizwan Haider, Heng-Yi Fang, Jie-Mei Yu, Zhan-Kun Jiang, Dong Liang, Yue Sun, Xian-Xia Yuan

Journal of Electrochemistry

For pervasive applications of fuel cells, highly efficient and economical materials are required to replace Pt-based catalysts for oxygen reduction reaction (ORR). In this study, the NiO@rGO, Pd-NiO@rGO and Ag-NiO@rGO nanoparticles were synthesized, and their catalytic performances toward ORR were investigated. The results revealed that all the three materials were capable of catalyzing ORR, but both the Pd-NiO@rGO and Ag-NiO@rGO showed the better performances compared with the NiO@rGO in terms of the reaction pathway being 4-electron process, the increases of the onset potential and the intermediate yielding rate, as well as the extended stability. Moreover, the effect of Pd modification …

Electrochemical Preparations And Applications Of Nano-Catalysts With High-Index Facets, Chi Xiao, Na Tian, Zhi-You Zhou, Shi-Gang Sun

Journal of Electrochemistry

The performance of catalysts highly depends on their surface structure and composition. Nanocrystals bounded by high-index facets usually exhibit high catalytic activity due to their high-density low-coordinated step atoms with high reactivity. In this paper, we have reviewed the preparations of noble metals (e.g., Pt, Pd and Rh) nanocatalysts with high-index facets by electrochemical square-wave potential method developed in our group. The square-wave potential method includes a nucleation procedure to generate nuclei, followed by a square-wave potential procedure for a certain period of time for the growth of nuclei into nanocrystals. The formation mechanism of high-index facets is also discussed. …

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of …

Investigating New Methods To Develop Perovskite Solar Cells, Amani Hussain Alfaifi

Electronic Theses and Dissertations

Discovering the potential of organic-inorganic metal halide perovskites (MHP) as a harvesting material in solar cells has strongly affected the research direction in solar energy. The fascinating optical and electronic properties offered by MHP combined with tremendous effort from scientists around the world have improved the efficiency to about 25% in a decade.

In the first part of the dissertation, we studied the lamination process as a new fabrication method for producing self-encapsulated perovskite solar cells based on laminating half stacks,as opposed to the conventional layer-by-layer method. Our work focused on optimizing the lamination process of complex triple cations perovskite …

Coarse-Grained Dynamically Accurate Simulations Of Ionic Liquids At Vacuum-Interface, Tyler D. Stoffel

Theses and Dissertations--Mechanical and Aerospace Engineering

Ionic liquids, possessing improved properties in many areas of technical application, are excellent candidates as components in development of next-generation technology, including ultra-high energy batteries. If they are thus applied, however, extensive interfacial analysis of any selected ionic configuration will likely be required. Molecular dynamics (MD) provides an advantageous route by which this may be accomplished, but can fall short in observing some phenomena only present at larger time/length scales than it can simulate. Often times this is approached by coarse-graining (CG), with which scope of simulation can be significantly increased. However, coarse-grained MD systems are generally known to produce …

Advanced Electrodes And Electrolytes For Long-Lived And High-Performance Lithium-Sulfur Batteries, Deepesh Gopalakrishnan

Wayne State University Dissertations

ABSTRACT

ADVANCED ELECTRODES AND ELECTROLYTES FOR LONG-LIVED AND HIGH-PERFORMANCE LITHIUM-SULFUR BATTERIES

by

DEEPESH GOPALAKRISHNAN

August 2020

Advisor: Dr. Leela Mohana Reddy Arava

Major: Mechanical Engineering

Degree: Doctor of Philosophy

Lithium – Sulfur (Li-S) batteries have received much attention and considered as a promising candidate for next generation energy storage devices because of their high theoretical energy density (≈2600 Wh kg‒1) and environmental friendliness. However, the uncontrollable growth of lithium dendrites in the lithium metal anode and the fatal effect of polysulfide shuttle hinder their practical applications. The formation of dendrites during repeated Li plating/stripping processes results in: reduced Li availability …

Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit

Theses and Dissertations

Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP in vitro. Encapsulating either PTX or LAP into nanoparticles increases drug potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than …

Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch

Theses and Dissertations--Chemical and Materials Engineering

Novel metallic thin film composite membranes are synthesized and evaluated in this work for improved separations and catalysis capabilities. Advances in technology that allow for improved membrane performance in solvent separations are desirable for low molecular weight organic separation applications such as those in pharmaceutical industries. Additionally, the introduction of catalytic materials into membrane systems allow for optimization of complex processes in a single step. By adding a nanostructured metallic thin film to its surface, a polymer membrane may be modified to exhibit these improved properties. Using magnetron sputtering, thin metal films may be deposited on commercially available membranes to …

Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong

Journal of Electrochemistry

P-nitrothiophenol (PNTP) is one of the most common probe molecules studied by surface-enhanced Raman spectroscopy (SERS). The research in electrochemical reduction behavior of PNTP will help understanding the mechanism for the nitrobenzene reduction. In this paper, we used transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to study the SERS of PNTP with cyclic voltammetry and chronoamperometry on gold electrodes. The results show that the TEC-SERS provide a time resolution that equals the transient electrochemical methods, and we concluded that the reaction was so quick that we did not observe the spectral information of intermediate species described in the literatures with a …

Electrochemical Sensor Based On Magnetic Electrode Modified With Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin For Determination Of Hydrogen Peroxide, Yang Yuan, Jia-Xin Wang, Yu-Hua Cao

Journal of Electrochemistry

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using Fe₃O₄@SiO₂ NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic Fe₃O₄ NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor …

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.

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 …

Peptide Nanotube Encapsulated Enzyme Biosensor For Vapor Phase Detection Of Malathion, An Organophosphorus Compound, Christopher W. Edwards, Surachet Duanghathaipornsuk, Mark N. Goltz, Sushil Kanel, Dong-Shik Kim

Faculty Publications

This study explores the use of a butyrylcholinesterase (BChE)-based, reversible reaction biosensor using screen-printed electrodes (SPEs) having a smaller working surface area than the single-use electrodes previously studied. Previous research demonstrated the prospective application of a single-use biosensor fabricated with an acetylcholinesterase (AChE) enzyme encapsulated in peptide nanotubes (PNTs) and enhanced with horseradish peroxidase (HRP) to detect organophosphorus compounds (OPCs) in aqueous and gas phases. In the current study, potential improvements to the biosensor are investigated. BChE-based biosensors were fabricated using PNTs, HRP, and Nafion in combination to increase the reactive surface area, enhance sensitivity, and maintain enzyme stability. Cyclic …

Roles Of Surfactant And Binary Polymers On Dissolution Enhancement Of Bcs Ii Drugs From Nanocomposites And Amorphous Solid Dispersions, Md Mahbubur Rahman

Dissertations

Drug nanocomposites and amorphous solid dispersions (ASDs) are two major formulation platforms used for the bioavailability enhancement of BCS Class II drugs. The major drawback of nanocomposites is their inability to attain high drug supersaturation during in vitro (<50% relative supersaturation) and in vivo dissolution. On the other hand, formulating an amorphous solid dispersion (ASD) with high drug loading (>20%) that releases drug rapidly, while generating and maintaining high supersaturation over at least three hours is challenging. The goal of this thesis is to develop a fundamental understanding of the impact of anionic surfactants–polymers on in vitro drug release from nanocomposites and ASDs, while addressing the above challenges. To achieve this goal, the following objectives are set: (1) compare griseofulvin …

Enzymatic Biofuel Cells In A Sandwich Geometry With Compressed Carbon Nanotubes/Enzyme Electrodes & Hybrid Patch Applications, Biao Leng

Dissertations

Enzymatic biofuel cells (EBFCs) convert the chemical energy of biofuels, such as glucose and methanol, into electrical energy by employing enzymes as catalysts. In contrast to conventional fuel cells, EBFCs have a simple membrane-free fuel cell design due to the high catalytic specificity of the enzymes, but the power densities obtained are lower. Although the primary goal of research on EBFCs has been to develop a sustainable power source that can be directly implanted in the human body to power bio-devices, other applications such as the use of a flexible film or fuel cell patch as a wearable power source …

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 …