Chemical Engineering Commons^™

An Investigation Of Conformality Of The Core-Shell Polymer Electrolyte Membrane (Pem) Fuel Cell Catalysts By Sputter Deposition, Mesut Yurukcu

Theses and Dissertations

Core-shell nanorod array geometry can offer enhanced durability for polymer electrolyte membrane (PEM) fuel cell electrodes if a catalyst shell is conformally coated around the nanorod support base. Uniform catalyst shell coating can minimize the interaction of acidic fuel cell medium with the nanorod base and can improve the overall electrocatalyst electrode stability. However, fabrication of the conformal shell layers on nanorod arrays using physical vapor deposition (PVD) methods (e.g. sputtering, thermal evaporation) has been a formidable task. In order to assess the PVD conditions for the production of conformal shell coatings, Monte Carlo simulation methods (MC) can provide useful …

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 …

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 …

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 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. …

First-Principles Study On The Catalytic Role Of Cerium Dioxide In The Conversion Of Organic Compounds, Chuanlin Zhao

LSU Doctoral Dissertations

Ceria is an earth-abundant material that has been widely used in heterogeneous catalysis, environmental catalysis, and energy applications thanks for its ability to readily convert between different oxidation states. The objective of this study is to theoretically elucidate the reaction mechanisms for the conversion of model organic compounds on ceria, in order to gain insights for the design of cost-effective and selective ceria-based catalysts. Acetaldehyde, acetic acid, and para-nitrophenyl phosphate monoester were selected as the model compounds to probe ceria surfaces. Density functional theory calculations can provide accurate predictions of adsorption and reaction energetics, which can be used to …

Photocatalytic Activity: Experimental Features To Report In Heterogeneous Photocatalysis, Md. Ariful Hoque, Marcelo I. Guzman

Chemistry Faculty Publications

Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scientific papers related to the photocatalysis field and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum efficiencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic …

Thin-Film Block Copolymers (Bcps) Self-Assembly As Versatile Patterning Scheme For Functional Nanomaterials, Le Zhang

LSU Master's Theses

Nanopattern generation is required for building various structural entities in every production process that involves nanostructures. Advancing nanopatterning technologies play an important role in developing and broadening the current nanopatterning technologies to meet up with the ever-demanding requirements in the realm of smaller feature sizes, smoother line-edge roughness (LER) and facile pattern transfer in pursuit of faster computer processors, better electrocatalysts and more compact and intelligent sensors, etc. Conventionally, patterning needs are heavily relied on photolithography, a technique that dominate chip-making industry for more than 50 years. However conventional photolithography is bounded by inherent resolution limits and difficult to be …

Nanoflower-Like Bi2moo6/Ag3po4 In Water Treatment, Xavier Morgan-Lange, Jaeyun Moon, Kaleab Ayalew

McNair Poster Presentations

• Environmental issues continue to intensify causing natural resources such as clean water to become increasingly scarce while demand only continues to grow. • Some of the most effective measures taken appear to be bioremediation tactics and their synthetic counterparts. • A critical area of interest are semi-conducting photocatalytic nanomaterials that take advantage of the photo-electric effect and use the introduction of ultra violet (UV) and visible light to induce oxidation and reduction reaction in p-type semiconductors. This results in the decomposition of certain pollutants and/or deactivates certain microbes in water. • These materials have the potential to operate using …

Engineering Metal-Ligand Interface For Selective Electrochemical Carbon Dioxide Reduction, Yuxin Fang

LSU Doctoral Dissertations

Unsustainable exploitation of fossil fuel and its massive greenhouse gas emission necessitates the development in alternative energy sources. Chemical fuels (CH₃OH or C₂H₅OH) outperform other choices, such as batteries for their high energy densities, which is key to portability. Electrochemical reduction of CO₂is capable of producing a wide range of valuable fuels (Syngas, formic acid, methane and methanol, etc.). Converting CO₂into carbon-based fuels further closes the carbon neutral cycle, which contributes to the effort in reducing global CO₂emission. Integration of organic ligands with transition metals shows great potential …

Assembling Of Niox/Mwcnts-Gc Anodic Nanocatalyst For Water Electrolysis Applications, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Saher D. Khamis Eng

Chemical Engineering

Glassy carbon (GC) electrode is intended to be modified with nickel oxide (NiOx) and multiwalled carbon nanotubes (MWCNTs) in the anodic reaction of water electrolysis. NiOx deposition time is optimized and a 5 min was enough to attain the maximum activity. A further modification of the catalyst with MWCNTs could greatly enhance its stability during continuous electrolysis. As an outcome, an energy amount of 21.7 kWh/KgO₂ is minimized. Several electrochemical and materials characterization setups will be utilized to test the catalyst activity and to know its geometry and structure.

An Aqueous All-Metal Oxide Asymmetric Supercapacitor With High Gravimetric And Volumetric Energy Densities, Xin Jing, Xu Zhang, Wei Wang, Jun-Wei Lang

Journal of Electrochemistry

Only with both high gravimetric and high volumetric energy densities, can supercapacitors find more extensive applications.In this paper, by making good use of the interesting nanostructures and the high packing densities of RuO₂ (nanoshpheres,1.69 g·cm^-3) and Co-Ni oxide (nanoflakes, 2.14 g·cm^-3), the RuO₂//KOH//Co-Ni oxide all-metal oxide asymmetric supercapacitors with high performance were successfully fabricated, which led to the maximum specific capacitance of 217.5 F·g^-1 (412.3 F·cm^-3) and specific energy density of 61.8 Wh·kg^-1 (121 Wh·L^-1) in a cell voltage between 0 and 1.5 V in KOH electrolyte. …

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Electrochemical Performances Of Neodymium Doped Lead Dioxide Composite Anode, Hong-Hui Wang, Ming-Jie Ma, Jie Feng, Huang-Ya Kang, Wen-Jie Huang

Journal of Electrochemistry

Neodymium (Nd) doped titanium (Ti)-based lead dioxide (PbO₂) composite anode was prepared by electrodeposition. The surface morphologies and crystal structures of the as-prepared anodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique, respectively. The electrochemical performances of PbO₂-Nd anode were studied by electrochemical impedance spectroscopy, linear sweep voltammetry and cyclic voltammetry. Additionally, the electrocatalytic activity and durability of PbO₂-Nd anode were investigated through the degradation of simulative refractory organic wastewater of phenol. The results showed that Nd doping made the PbO₂ anode surface structure dense and uniform with smaller …

Fabrication Of Mnox/Mwcnts-Gc Nanocatalyst For Oxygen Evolution Reaction, Yaser M. Asal Mr, Islam M. Al-Akraa Dr, Amr M. Arafa Eng.

Chemical Engineering

Manganese oxide (MnOx) and multiwalled carbon nanotubes (MWCNTs) are intended to modify the GC electrode for oxygen evolution reaction (OER). Optimization of MnOx loading is carried out and the deposition of 55 cycles was sufficient to obtain the highest activity toward OER. The stability of the catalyst is enhanced by the addition of MWCNTs. As a result, an amount of 22 kWh/Kg of O₂ of energy is saved. Several techniques including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy will be combined to track the catalyst activity and to determine its …

Identification Of Proximal And Isolated Aluminum Heteroatoms In Zeolites By Infrared Spectroscopy, Melanie A. Brunet Torres, Philip Kester, Rajamani Gounder

The Summer Undergraduate Research Fellowship (SURF) Symposium

High demand for energy production and limited fossil fuel reserves are two factors that motivate intense research for new alternative energy resources. While we are still far from completely moving to renewable energy solutions, a new solution that replaces crude oil and coal with shale gas is currently under investigation. For this modern technology, new zeolite catalysts need to be developed for the conversion of light hydrocarbons gases to liquid transportation fuels. These catalysts are of special interest in the production of liquid fuels since they exhibit high reaction rates, molecular sieving properties and selectivity behavior. In this work, the …

Platinum-Gallium (Pt-Ga) Intermetallic Alloys For Propane Dehydrogenation, Brittany K. Roopnarine, Nicole J. Libretto, Johnny Zhuchen, Zhenwei Wu, Evan Wegener, Griffin Canning, Abhaya K. Datye, Jeffrey T. Miller

The Summer Undergraduate Research Fellowship (SURF) Symposium

Natural gas is a source of energy for the United States. The Center for Innovative Strategic Transformation of Alkane Resources (CISTAR) plans to use shale gas extracted from shale rock formations as a bridge fuel to replace coal and oil while the US transitions to renewable energy like solar and wind. After methane, the largest components in shale gas are light alkanes such as ethane and propane. These can be catalytically converted to olefins, which can be further reacted to produce fuels, for example. Olefins from alkanes can be accomplished by dehydrogenation by promoted platinum alloys. This study compares the …

Investigation Of The Effects Of Solid-State Treatments On The Structure And Mobility Of Copper In Zeolites, Jiayang Wu, Laura Wilcox, Rajamani Gounder

The Summer Undergraduate Research Fellowship (SURF) Symposium

Zeolites are microporous, aluminosilicate catalysts that play an important role in industrial applications as well as studies for the fundamental understanding of catalysts for emerging reactions of interest. The introduction of aluminum into the zeolite lattice introduces a negative charge on the framework that can be balanced with extra-framework cations. The control of the aluminum distribution and the choice of charge balancing cations allows for the ability to tailor the active sites to facilitate a desired reaction. This research focuses on studying copper active sites in zeolites. Copper oxide was used as a copper precursor to introduce copper ions in …

Computational Catalysis: Creating A User-Friendly Tool For Research And Education, Kevin P. Greenman, Peilin Liao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Catalysis is used in a significant portion of production processes in the industrialized world, including most processing of chemicals and fuels. This makes maximizing the efficiency of catalysts a high priority. However, the immense number of candidates for new catalysts precludes the possibility of testing all of them by experiments. Density functional theory (DFT) has been widely and successfully used to calculate material properties relevant to catalysis and to screen promising candidates for experimental testing, but there currently exists no publicly- available, user-friendly tool for performing these DFT calculations. This work details the development of such a tool for nanoHUB.org …

Scaling Relationships Across Chemically Related Adsorbates For Fast Screening Of Alloy Catalysts For Propane Dehydrogenation, Anne Esther Serban, Ranga Rohit Seemakurthi, Brandon C. Bukowski, Jeffrey Greeley

The Summer Undergraduate Research Fellowship (SURF) Symposium

A catalyst is a material which speeds up the rate of a specific reaction. A reaction that is of significant importance to the chemical industry is the selective transformations of light alkanes (ethane, propane), which are largely available in shale gas, to olefins. These olefins can then be converted into higher-value chemicals, materials, and fuels. However, there are several undesired reactions that take place alongside the main dehydrogenation reaction, so a catalyst of high selectivity is desired. Apart from the industrially used PtSn catalyst, work by our experimental collaborators has shown that various other Pt and Pd alloys (In, Zn) …

Electrocatalytic Properties Of Ni-Fe Basedalloys Toward Oxygen Evolution Reaction, Xiaodan Cui

LSU Doctoral Dissertations

In this dissertation, laser-based manufacturing was applied to develop NiFe-based alloys, with focus on their electrochemical characteristics toward oxygen evolution reaction during water electrocatalysis. The targeted electrocatalysts were designed by combining catalysis principles of absorption energy, electronic effect and geometry effect. Firstly, a one-step laser-based manufacturing method was applied to prepare a thin layer of NiFe-based electrodes with varied Ni to Fe ratios to replace high-cost noble metals as the electrocatalyst for oxygen evolution reaction (OER). Since each Ni has 0.6 d-vacancy and each Fe atom has 2.2 d-vacancies. The alloying of Ni-Fe allows electrons flowing from Ni to Fe, …

Chemical Stability Investigations Of Catalyst Layer In Pemfc, Yan-Yan Gao, Ming Hou, Yong-Yi Jiang, Dong Liang, Jun Ai, Li-Min Zheng

Journal of Electrochemistry

This work was intended to study the effect of free radicals on the chemical stability of catalyst layer via ex situ accelerated stress test (AST). Fenton reagent was used as the free radical provider in this research. Apart from the decomposition of Nafion in catalyst layer, the agglomerated Pt nanoparticles and the corroded carbon support were also observed after being treated in Fenton reagent for 100 h. Firstly, the existence of fluoride (F) ions evidenced the chemical decomposation of Nafion after being attacked by trace radical species, which was supported by the intensity decrease in the C-F stretching and vibration …

Recent Progress For Fe-N-C Electrocatalysts In Alkaline Fuel Cells, Xin Deng, Heng-Quan Chen, Ye Hu, Qing-Gang He

Journal of Electrochemistry

Fuel cells are highly recommended nowadays due to their intrinsic advantages such as high energy conversion efficiency, nearly no pollution, and convenient operation. With the development of anion exchange membrane, alkaline fuel cells have gone through a renaissance thanks to their superiorities such as faster reaction kinetics, wider choices for both fuels and electrocatalysts. It is essential to find an appropriate electrocatalyst for oxygen reduction reaction (ORR) to improve the performance of alkaline fuel cells. Further commercialization of the widely used Pt-based materials has suffered from disadvantages such as scarcity and high cost. As alternatives to largely investigated Pt-based materials, …

Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin

Journal of Electrochemistry

By using graphitic carbon nitride nanosheet (g-C₃N₄ nanosheet) as a support,Pt/g-C₃N₄ nanosheet catalyst was fabricated by microwave assisted polylol process. The nanoparticles size,composition,structure and optical properties of Pt/g-C₃N₄ nanosheet were characterized by TEM,XRD,XPS and UV-Vis diffuse reflectance spectroscopy. Comparing with the catalytic activities toward formic acid electro-oxidation under dark and visible light illumination,the superior activity of Pt/g-C₃N₄ nanosheet catalyst was achieved under visible light illumination. This visible light-driven enhancement in the formic acid performance could be attributed to the plasmon-induced electron-hole separation on g-C₃N₄ with …

Carbon Composite Fe3O4 Nanoparticles Based Electrochemical Sensor For Hydrogen Peroxide Detection, Si-Yu Zhang, Hui-Juan Wang, Shu-Fang Li, Jian-Ying Qu

Journal of Electrochemistry

In this work, a novel hydrogen peroxide electrochemical sensor was constructed with ferroferric oxide (Fe₃O₄) magnetic nanoparticles, which demonstrated good electrocatalytic activity for hydrogen peroxide. There existed a good linear relationship between the concentration of hydrogen peroxide and the oxidation peak current in the range of 1.00 × 10^-6 ~ 1.00 × 10^-3 mol·L^-1 (R = 0.9980) with the detection limit of 6.60 × 10-7 mol·L^-1. The sensor exhibited good anti-interference ability, high reproducibility and stability.

Lead Modified Nanoporous Platinum Electro-Catalysts For Formic Acid Oxidation, Yuan-Yuan Zhang, Qing-Feng Yi, Ge-Kun-Kun Zuo, Tao Zou, Xiao-Ping Liu, Xiu-Lin Zhou

Journal of Electrochemistry

Platinum (Pt) catalysts modified by other suitable metals significantly enhance their electrochemical activities for formic acid oxidation. In this work, a titanium-supported nanoporous network platinum (nanoPt/Ti) electrode was prepared using a hydrothermal method. The as-prepared nanoPt/Ti electrode was modified with a certain amount of lead by using cyclic voltammetry for different scan cycle numbers (n), namely, n = 10, 15, 20 and 30, to synthesize the novel lead-modified nanoporous Pt (nanoPb_(n)-Pt/Ti) electrodes. Electro-oxidation of formic acid on these electrodes was studied with cyclic voltammetry (CV), chronoamperometry and chronopotentiometry in sulfuric acid solution. CV curves showed that both nanoPt/Ti …

Increased Energy Yield Through Fast Pyrolysis: Empowering Malawian Villages, Diehl Mutamba

Undergraduate Honors Theses

Biomass contributes to several renewable energy technologies. This project will explore the use of fast pyrolysis to produce fuels by designing an apparatus for fast pyrolysis. Malawian people harvest firewood from the forests, which is a major contributor to deforestation. Furthermore, they convert some of it to charcoal with about 10-15% efficiency to sell to city dwellers. The project will enable herbaceous fuels to replace wood, increase charcoal yields and create new products. Firewood and charcoal produce smoke and carbon monoxide (CO) that compromises the villagers’ health.

This project will address deforestation problems, improve sustainability, decrease health hazards and improve …

Experimental Evaluation Of Lignocellulosic Biomass Pyrolysis By Dielectric Heating And Thermocatalytic Upgrading Of Pyrolysis Vapors Via Iron-Doped Montmorillonite Clay Catalyst, Candice Raffaela Ellison

LSU Doctoral Dissertations

This work is an investigation of microwave-assisted biomass pyrolysis and thermocatalytic upgrading of pyrolysis vapors. In the first two chapters, the microwave susceptibility of mixtures of biomass with potential microwave absorbers are characterized by dielectric measurements at microwave frequencies. Dielectric constant and dielectric loss factor of biomass mixtures with char and biomass mixtures with bentonite are found to increase quadratically with increasing weight percent of char or bentonite.

Chapter 3 presents a finite element model, developed in COMSOL Multiphysics, comparing two waveguide applicator configurations for microwave processing using biomass as a model material. A standing wave configuration results in intense …

Method Of Increasing Mass Transfer Rate Of Acid Gas Scrubbing Solvents, Cameron Anthony Lippert, Kunlei Liu, Christine Marie Brandewie, Joseph Eugene Remias, Moushumi Sarma

Center for Applied Energy Research Faculty Patents

A method and catalysts for increasing the overall mass transfer rate of acid gas scrubbing solids is disclosed. Various catalyst compounds for that purpose are also disclosed.

Addition Of Exothermic Reaction Scale-Up Lab To Unit Operations Curriculum., Lisa A Anderson

Electronic Theses and Dissertations

According to the Chemical Safety Board’s 2002 report entitled "Improving Reactive Hazard Management,” the CSB identified 167 serious accidents involving uncontrolled chemical reactions in the United States between 1980 and 2001 causing 108 deaths and hundreds of millions of dollars in property damage. Of the 167 accidents, 35% involved runaway reactions. One noteworthy incident from recent history is the fatal explosion that occurred at T2 Laboratories in Jacksonville, FL as a result of improper scale-up and an insufficient cooling design for the system.

One recommendation resulting from the CSB investigation of the incident was that the Accreditation Board for Engineering …