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Chemical Engineering

Oxidation

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Full-Text Articles in Engineering

Novel Investigation Of Catalytic Hydrogenation And Oxidation Of 1,3-Butadiene, Ali M. Alabedkhalil Jun 2023

Novel Investigation Of Catalytic Hydrogenation And Oxidation Of 1,3-Butadiene, Ali M. Alabedkhalil

Theses

The hydrogenation of 1,3 Butadiene (BD) is an important industrial process that is generally used to generate butene, which is a key feedstock to produce a variety of chemicals such as polymers, plastic, and synthetic rubber. This process involves reacting BD with hydrogen using different metallic Ni-based catalysts. In this study, Ni/Al2O3 and Ni/Nb2O5 catalysts were used and investigated to perform the hydrogenation reaction because of their commercial availability, effective hydrogenation activity, and affordability compared to Platinum Group Metal (PGM) catalysts.

The catalytic reactions were conducted using a quartz tube reactor between a temperature range …


Atomic Layer Deposited Pt/Tio2-Sio2 And Pt/Zro2-Sio2 For Sequential Adsorption And Oxidation Of Vocs, Busuyi O. Adebayo, Han Yu, Ali A. Rownaghi, Xinhua Liang, Fateme Rezaei Sep 2022

Atomic Layer Deposited Pt/Tio2-Sio2 And Pt/Zro2-Sio2 For Sequential Adsorption And Oxidation Of Vocs, Busuyi O. Adebayo, Han Yu, Ali A. Rownaghi, Xinhua Liang, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

In this work, Pt nanoparticles were loaded on SiO2, TiO2-thin-film-modified SiO2 (TiO2-SiO2), or ZrO2-thin-film-modified SiO2 (ZrO2-SiO2) particles and the composites were investigated for sequential adsorption and desorption/catalytic oxidation of benzene. The SiO2 was prepared via sol–gel method, while TiO2-SiO2 and ZrO2-SiO2 were synthesized via atomic layer deposition (ALD) thin film coating of TiO2 or ZrO2 on SiO2 particles substrate. In the sequential capture-reaction tests, the materials were first exposed to ca. 500 ppmv benzene …


Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis, Lauren B. Shepard May 2022

Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis, Lauren B. Shepard

Chemical Engineering Undergraduate Honors Theses

Water electrolysis has been proposed as a renewable source of hydrogen, a possible replacement to harmful fossil fuels. This process can be broken down into two half reactions, the hydrogen evolution reaction and the oxygen evolution reaction. Because the oxygen evolution reaction has slow kinetics and a high overpotential to overcome, a catalyst is needed to speed up the kinetics and ensure faster and more efficient production of molecular hydrogen. The use of Ni-Fe hydroxide alloy nanoparticles as a catalyst has been shown to significantly improve the efficiency of the reaction by decreasing the overpotential, making the process more energy …


Advanced Raman Spectroscopy Detection Of Oxidative Damage In Nucleic Acid Bases: Probing Chemical Changes And Intermolecular Interactions In Guanosine At Ultralow Concentration, Francesca Ripanti, Claudia Fasolato, Flavia Mazzarda, Simonetta Palleschi, Marina Ceccarini, Chunchun Li, Margherita Bignami, Enrico Bodo, Steven E.J. Bell, Filomena Mazzei, Paolo Postorino Jan 2021

Advanced Raman Spectroscopy Detection Of Oxidative Damage In Nucleic Acid Bases: Probing Chemical Changes And Intermolecular Interactions In Guanosine At Ultralow Concentration, Francesca Ripanti, Claudia Fasolato, Flavia Mazzarda, Simonetta Palleschi, Marina Ceccarini, Chunchun Li, Margherita Bignami, Enrico Bodo, Steven E.J. Bell, Filomena Mazzei, Paolo Postorino

Bioelectrics Publications

DNA/RNA synthesis precursors are especially vulnerable to damage induced by reactive oxygen species occurring following oxidative stress. Guanosine triphosphates are the prevalent oxidized nucleotides, which can be misincorporated during replication, leading to mutations and cell death. Here, we present a novel method based on micro-Raman spectroscopy, combined with ab initio calculations, for the identification, detection, and quantification of oxidized nucleotides at low concentration. We also show that the Raman signature in the terahertz spectral range (<100 >cm(-1)) contains information on the intermolecular assembly of guanine in tetrads, which allows us to further boost the oxidative damage detection limit. Eventually, we …


A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin Dec 2020

A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin

Faculty Publications

High entropy alloys (HEAs) are promising candidates for high-temperature structural material applications. Oxidation is a major factor that must be accounted for when designing such materials and it is thus important to study the oxidation behavior of HEAs to enable the optimum design of next generation materials. In this study, the thermodynamic behavior of interstitial oxygen in a Mo-Nb-Ta-W high entropy alloy was explored beyond the dilute limit. This was accomplished by sampling configurations of the HEA and HEA-oxygen systems from an isothermal–isobaric ensemble using a series of first-principle-based Monte Carlo simulations. It was found that the interstitial oxygen had …


Characterization And Electrochemical Performance Of Dopamine-Sensitized Titania Thin Films, Joshua Garay Jan 2020

Characterization And Electrochemical Performance Of Dopamine-Sensitized Titania Thin Films, Joshua Garay

Theses and Dissertations--Chemical and Materials Engineering

Sensitization of mesoporous titania films with dopamine and polydopamine for visible light photoelectrochemical activity is investigated. Sensitization effectiveness is compared with 8 mM dopamine solutions of varying pH (acidic, basic, and neutral), as well as with a basic polydopamine solution. Vibrational changes due to dopamine attachment are determined from detached powders by Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) is used to quantify organics attached. X-ray photoelectron spectroscopy (XPS) of intact films probes the chemically induced charge shift from dopamine attachment. Cyclic voltammetry identifies the irreversible dopamine oxidation and tin reduction voltages. Finally, chronoamperometric curves are used to compare …


Improving Boron For Combustion Applications, Kerri-Lee Annique Chintersingh Aug 2019

Improving Boron For Combustion Applications, Kerri-Lee Annique Chintersingh

Dissertations

Boron has received much attention as a potential additive to explosives and propellants due to its high theoretical gravimetric and volumetric heating values. The challenge, however, is that boron particles tend to agglomerate, have lengthy ignition delays and very low combustion rates. Prior research indicates that boron’s long ignition delays are due to its inhibiting naturally occurring oxide layer, impeding the diffusion of reactants for oxidation. For combustion, current studies report that boron particles have two consecutive stages, but the actual reaction mechanism is poorly understood. Despite many years of relevant research, quantitative combustion data on micron-sized boron particles are …


Reaction Of Titanium Subhydride With Multiple Passivating Gasses, Erik C. Strobert Jr Jan 2019

Reaction Of Titanium Subhydride With Multiple Passivating Gasses, Erik C. Strobert Jr

Chemical and Biological Engineering ETDs

Sandia National Laboratories has used substoichiometric titanium hydride as a pyrotechnic fuel for decades. Production of titanium subhydride requires partial dehydriding of titanium hydride powder and subsequent chemical passivation to render the resultant bare titanium surface nonreactive and the powder non-pyrophoric. Novel passivation techniques, using a gas other than air, have been suggested in the past but have never been investigated. This work examines the reaction kinetics of titanium subhydride with three passivating agents, nitrogen, oxygen, and propane. These passivation experiments took place under isothermal conditions (420 ˚C) with varied dehydriding and passivation time periods. It was found that the …


Catalytic Waste Gasification: Water-Gas Shift & Selectivity Of Oxidation For Polyethylene, Mason J. Lang Jan 2019

Catalytic Waste Gasification: Water-Gas Shift & Selectivity Of Oxidation For Polyethylene, Mason J. Lang

ETD Archive

As landfills approach capacity and take up valuable land space, metropolitan areas have realized the need for waste disposal alternatives. Thus, there has been a widespread use of waste incinerators in Europe and the United States [1]; [2]. Although newer technology has made incinerators more efficient, there is an increasing interest in formulating `greener’ alternatives to incinerators. Gasification converts organic and carbonaceous materials into a combination of gaseous products known as “syngas,” or synthetic gas. This process greatly reduces the amount of hazardous emissions. The syngas produced by gasifiers has a wide range of uses, including their conversion into diesel, …


Elucidation Of The Catalytic Partial Oxidation Of Methane Utilizing The One-Of-A-Kind Catalytic Shock Tube Technique, Robyn E. Smith Jan 2019

Elucidation Of The Catalytic Partial Oxidation Of Methane Utilizing The One-Of-A-Kind Catalytic Shock Tube Technique, Robyn E. Smith

Dissertations and Theses

The mechanism for the catalytic partial oxidation of methane has been debated in scientific literature for over 20 years. This is a seemingly simple reaction producing CO, CO2, H2 and H2O through either partial oxidation followed by complete oxidation or complete oxidation followed by reforming steps. What is happening when the reaction is allowed to occur in an environment absent of transport limitations, absent of temperature gradients and temperature changes, absent of boundary layers must be understood and, until now, has yet to be achieved in one experimental technique.

A novel method using a one …


Evaluation And Prevention Of Spontaneous Combustion During Handling And Storage Of Coal, Amir E. Najarzadeh Jan 2018

Evaluation And Prevention Of Spontaneous Combustion During Handling And Storage Of Coal, Amir E. Najarzadeh

Theses and Dissertations--Mining Engineering

Spontaneous combustion of coal has historically been a major problem for the coal industry, predominantly during storage and transportation. Various methods have been used in the laboratory for evaluating the propensity of different coal sources to self-heat. However, the heterogeneity of coal and the complexity of the system has resulted in inconsistencies and sometimes conflicting results as indicated by the findings reported in several publications.

The primary objective of the current study was to build a laboratory scale apparatus that simulates the condition of a coal stockpile to evaluate the events leading to spontaneous combustion and develop potential remedies. As …


Catalytic Oxidation And Depolymerization Of Lignin In Aqueous Ionic Liquid, Lalitendu Das, Siquan Xu, Jian Shi Aug 2017

Catalytic Oxidation And Depolymerization Of Lignin In Aqueous Ionic Liquid, Lalitendu Das, Siquan Xu, Jian Shi

Biosystems and Agricultural Engineering Faculty Publications

Lignin is an integral part of the plant cell wall, which provides rigidity to plants, also contributes to the recalcitrance of the lignocellulosic biomass to biochemical and biological deconstruction. Lignin is a promising renewable feedstock for aromatic chemicals; however, an efficient and economic lignin depolymerization method needs to be developed to enable the conversion. In this study, we investigated the depolymerization of alkaline lignin in aqueous 1-ethyl-3-methylimidazolium acetate [C2C1Im][OAc] under oxidizing conditions. Seven different transition metal catalysts were screened in presence of H2O2 as oxidizing agent in a batch reactor. CoCl2 and …


Enhanced Oxidation Of Organic Contaminants By Ferrate: Acid-Activated And Silica Gel-Enhanced Ferrate(Vi) Oxidation Processes, Kyriakos Manoli Aug 2017

Enhanced Oxidation Of Organic Contaminants By Ferrate: Acid-Activated And Silica Gel-Enhanced Ferrate(Vi) Oxidation Processes, Kyriakos Manoli

Electronic Thesis and Dissertation Repository

Recently, the tetraoxy high-valent iron(VI), known as ferrate(VI) (Fe(VI); FeVIO42), received a great attention as a water-treatment chemical, because of its unique oxidation, disinfection, and coagulation properties. Though Fe(VI) has shown remarkable efficiency in oxidizing several pollutants in water, it has sluggish reactivity with some emerging organic contaminants, especially at basic pH conditions. Thus, the main objective of this PhD thesis was to activate or catalyze Fe(VI) oxidation reactions, at mild alkaline pH conditions, to enhance the oxidative transformation of organic pollutants and reduce the required dosage of Fe(VI) and contact time.

The activation of …


Effect Of Surface Oxidation On The Mechanics Of Carbon Nanotube Laden Interfaces, William Daniel Ivancic Jan 2017

Effect Of Surface Oxidation On The Mechanics Of Carbon Nanotube Laden Interfaces, William Daniel Ivancic

ETD Archive

Single and multi-walled carbon nanotubes (SWCNT & MWCNT) have been studied over the past three decades because of their excellent properties, including their mechanical strength and large electrical and thermal conductivities. Incorporating CNTs into phases necessary for use in consumer or industrial products has been challenging because of strong attractive interactions, heterogeneity, and lack of separation techniques for these nanomaterials. Moreover, there are further challenges incorporating CNTs into multiphase materials because of the many remaining open questions regarding the properties of an interface with CNTs adsorbed or nearby. In the present work, the mechanics and microstructure of a water/air interface …


Modeling Soot Oxidation And Gasification With Bayesian Statistics, Alexander Jon Josephson, Neal D. Gaffin, Sean T. Smith, Thomas H. Fletcher, David Lignell Jan 2017

Modeling Soot Oxidation And Gasification With Bayesian Statistics, Alexander Jon Josephson, Neal D. Gaffin, Sean T. Smith, Thomas H. Fletcher, David Lignell

Faculty Publications

This paper presents a statistical method for model calibration using data collected from literature. The method is used to calibrate parameters for global models of soot consumption in combustion systems. This consumption is broken into two different submodels: first for oxidation where soot particles are attacked by certain oxidizing agents; second for gasification where soot particles are attacked by H2O or CO2 molecules. Rate data were collected from 19 studies in the literature and evaluated using Bayesian statistics to calibrate the model parameters. Bayesian statistics are valued in their ability to quantify uncertainty in modeling. The calibrated consumption model with …


Oxidation Process Of H 2 O /Uv For Cod Reduction Of Wastewater From Soybean Tofu Production, Komala Pontas, Abrar Muslim Dec 2015

Oxidation Process Of H 2 O /Uv For Cod Reduction Of Wastewater From Soybean Tofu Production, Komala Pontas, Abrar Muslim

Makara Journal of Technology

Chemical Oxygen Demand (COD) reduction of wastewater from soybean tofu production was studied by conducting advanced oxidation process (AOP) using hydrogen peroxide with UV radiation catalysts in a closed cylindrical glass reactor. The hydroxyl radical (*OH) concentration from H2O2 decomposition was modeled, and exponential trends were found for the *OH concentration over radiation time and operation temperature. As a result, it was found that the maximal *OH concentration was 0.209 mol L-1 at 240 minutes and 50 °C. The *OH concentration exponentially increased following rise in operation temperature. The H2O2/UV AOP application reduced COD concentration to approximately 42.41% from 10,545 …


Transmission Electron Microscopy Characterization Of High-Temperatur Oxidation Of Fe-20cr-5al Alloy Prepared By Focused Ion Beam Technique, Mohammad Dani, Pudji Untoro, Teguh Yulius Surya Panca Putra, Parikin Parikin, Joachim Mayer, Arbi Dimyati Aug 2015

Transmission Electron Microscopy Characterization Of High-Temperatur Oxidation Of Fe-20cr-5al Alloy Prepared By Focused Ion Beam Technique, Mohammad Dani, Pudji Untoro, Teguh Yulius Surya Panca Putra, Parikin Parikin, Joachim Mayer, Arbi Dimyati

Makara Journal of Technology

The Focused Ion Beam (FIB) technique was applied for cross section preparation of the oxidized alloy for Transmission Electron Microscopy (TEM) study. Prior to preparation, the specimens of Fe-20Cr-5Al alloy sheet were oxidized in air at 1200 oC for 2 minutes, 10 minutes, 2 hours, and 100 hours. The microstructure and elemental composition of the samples were characterized using TEM equipped with an Energy Dispersive X-Ray Spectroscopy (EDX). The Electron Energy Loss Spectroscopy (EELS) was used to determine of the light elements. The TEM investigation reveals remarkable microstructure evolution of the specimens during oxidation which generally exhibit a typical multi-layer …


Sustainable Decolorization Of Reactive And Acid Dye Wastewater Using Photo-Fenton Oxidation Both With And Without Biodegradation: Laboratory And Field Studies, Marissa R. Jablonski May 2015

Sustainable Decolorization Of Reactive And Acid Dye Wastewater Using Photo-Fenton Oxidation Both With And Without Biodegradation: Laboratory And Field Studies, Marissa R. Jablonski

Theses and Dissertations

Photo-Fenton oxidation is an advanced oxidation process (AOP) used to degrade low-concentration textile dye wastewater using expensive chemicals. The technique has shown promise in laboratory-scale projects, but has not been scaled up sustainably to function for industry. Aerobic biodegradation is a common biological treatment method used in large-scale textile industrial applications that generates large amounts of hazardous biological waste. This waste is often left open to the elements and subsequently leaches into natural waterways or onto land. This is the first study of its kind to combine the two to treat cottage-scale industry-grade textile wastewater with a dye concentration of …


Naio4 Oxidation Of Mussel Adhesive Protein Film And Its Corrosion Protection For Mg-1.0ca Alloy, Rui-Qing Hou, Ping-Li Jiang, Shi-Gang Dong, Chang-Jian Lin Feb 2015

Naio4 Oxidation Of Mussel Adhesive Protein Film And Its Corrosion Protection For Mg-1.0ca Alloy, Rui-Qing Hou, Ping-Li Jiang, Shi-Gang Dong, Chang-Jian Lin

Journal of Electrochemistry

The effect of oxidation of mussel adhesive protein (Mefp-1) film on the corrosive resistance for Mg-1.0Ca alloy was investigated by scanning electron microscopy (SEM), atom force microscopy (AFM), electron probe microanalysis (EPMA), Infrared reflection absorption spectroscopy (IRAS) and electrochemical methods. The results showed that the NaIO4 induced oxidation of the pre-formed Mefp-1 film with porous morphology involved structural change of the DOPA group in the protein and resulted in a more uniform film with net-like morphology. The protein film without oxidation had an increasing resistance for the corrosion of Mg-1.0Ca alloy up to 7 days exposure. After oxidation, Epit …


Synthesis Of Carbonyl Compounds From Alcohols Using Electrochemically Generated Superoxide Ions In Rtils, Praneshwar Sethupathy, Inas Alnashef, John Monnier, Michael Matthews, John Weidner Sep 2014

Synthesis Of Carbonyl Compounds From Alcohols Using Electrochemically Generated Superoxide Ions In Rtils, Praneshwar Sethupathy, Inas Alnashef, John Monnier, Michael Matthews, John Weidner

Michael A. Matthews

No abstract provided.


Electrochemical Fabrication Of Two-Dimensional Flower-Like Pt Nanostructures For Methanol Electrocatalytic Oxidation, Xia Wang, Jun Hu, Yong-Jun Li Aug 2014

Electrochemical Fabrication Of Two-Dimensional Flower-Like Pt Nanostructures For Methanol Electrocatalytic Oxidation, Xia Wang, Jun Hu, Yong-Jun Li

Journal of Electrochemistry

Two-dimensional flower-like Pt nanostructures (2D FPNs) were fabricated on glassy carbon substrates by galvanostatical electrochemical technique. The electrolyte was the HAuCl4 + HClO4 aqueous solution without addition of any structure-directing organic reagent, which made as-prepared Pt nanostructures cleaner, exhibiting much higher reactivity. Scanning electron microscopic images revealed that 2D FPNs were spherical Pt nano-flowers constructed by the smallest building blocks, nano-leaves. The number density of spherical Pt nano-flowers can be tuned by controlling the electrodeposition time. High resolution transmission electron microscopic images indicated that each nano-leaf was formed by growing along Pt(111) direction. Electrocatalytic activities of as-prepared 2D …


Oxidation-Resistant, Solution-Processed Plasmonic Ni Nanochain-SioX (X < 2) Selective Solar Thermal Absorbers, Xiaobai Yu, Xiaoxin Wang, Qinglin Zhang, Juchuan Li, Jifeng Liu Aug 2014

Oxidation-Resistant, Solution-Processed Plasmonic Ni Nanochain-SioX (X < 2) Selective Solar Thermal Absorbers, Xiaobai Yu, Xiaoxin Wang, Qinglin Zhang, Juchuan Li, Jifeng Liu

Chemical and Materials Engineering Faculty Publications

Metal oxidation at high temperatures has long been a challenge in cermet solar thermal absorbers, which impedes the development of atmospherically stable, high-temperature, high-performance concentrated solar power (CSP) systems. In this work, we demonstrate solution-processed Ni nanochain-SiOx (x < 2) and Ni nanochain-SiO2 selective solar thermal absorbers that exhibit a strong anti-oxidation behavior up to 600 °C in air. The thermal stability is far superior to previously reported Ni nanoparticle-Al2O3 selective solar thermal absorbers, which readily oxidize at 450 °C. The SiOx (x < 2) and SiO2 matrices are derived from hydrogen silsesquioxane and tetraethyl orthosilicate precursors, respectively, which comprise Si-O cage-like …


Spectroscopic Investigation Into Oxidative Degradation Of Silica-Supported Amine Sorbents For Co2 Capture, Chakravartula Srikanth, Steven Chuang Jul 2014

Spectroscopic Investigation Into Oxidative Degradation Of Silica-Supported Amine Sorbents For Co2 Capture, Chakravartula Srikanth, Steven Chuang

Steven S.C. Chuang

Oxidative degradation characteristics of silica-supported amine sorbents with varying amounts of tetraethylenepentamine (TEPA) and polyethylene glycol (PEG; P200 or P600 represents PEG with molecular weights of 200 or 600) have been studied by IR and NMR spectroscopy. Thermal treatment of the sorbents and liquid TEPA at 100 °C for 12 h changed their color from white to yellow. The CO2 capture capacity of the TEPA/SiO2 sorbents (i.e., SiO2-supported TEPA with a TEPA/SiO2 ratio of 25:75) decreased by more than 60 %. IR and NMR spectroscopy studies showed that the yellow color of the degraded sorbents resulted from the formation of …


Pulse Electrodeposition Of Pd-Ni Alloy Nanoparticles For Electrocatalytic Oxidation Of Formic Acid, Fang-Zu Yang, Jun-Pei Yue, Zhong-Qun Tian, Shao-Min Zhou Feb 2014

Pulse Electrodeposition Of Pd-Ni Alloy Nanoparticles For Electrocatalytic Oxidation Of Formic Acid, Fang-Zu Yang, Jun-Pei Yue, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

The Pd-Ni alloy nanoparticles with nickel atomic contents of 12.0%, 16.4% and 22.6% were successfully electrodeposited from a Pd-Ni alloy electrolyte by square wave pulse plating. The alloy nanoparticles were in the spherical shape with a diameter of 50 ~ 80 nm. As the growth potential of the alloy was negatively shifted, the nickel content of the alloy was increased, and the size of the nanoparticles was almost the same, whereas the number, the degree of crosslinking and the real active area of the nanoparticles were increased. As the nickel content of the alloy nanoparticles increased, the peak current for …


An Intrinsic Model For Graphite Oxidation And The Effects Of Microstructural Features On Apparent Rate, Joshua J. Kane Aug 2013

An Intrinsic Model For Graphite Oxidation And The Effects Of Microstructural Features On Apparent Rate, Joshua J. Kane

Boise State University Theses and Dissertations

The very high temperature reactor (VHTR) is the latest generation of high-temperature gas-cooled reactors (HTGR). The VHTR has higher outlet temperatures than a traditional HTGR with outlet temperatures up to 1000 °C. This high outlet temperature permits emissions-free process heat in the form of high-quality steam for high temperature industrial applications. Moreover, the high temperatures of the reactor could potentially be used for hydrogen production from water or high efficiency electrical power production (~50% efficiency of thermal to electrical power conversion).

The VHTR is designed to employ helium as its coolant and uses graphite for its neutron moderator and as …


Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner Feb 2012

Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner

John W Weidner

A proton exchange membrane fuel cell was used as a flow reactor for continuous preferential oxidation of CO over H2 from 1.0% CO in H2 under pulse-potential control. By varying the pulse profile ~e.g., on-time, off-time, pulse potential! the CO and H2 oxidation currents were varied independently. The improvement in faradaic selectivity between CO and H2 oxidation results from the promotion of CO adsorption during the off ~i.e., open-circuit! portion of the pulse. Therefore, during the on portion CO oxidation was preferred while the surface was covered with CO.


Development Of A Novel Co Tolerant Proton Exchange Membrane Fuel Cell Anode, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang Feb 2012

Development Of A Novel Co Tolerant Proton Exchange Membrane Fuel Cell Anode, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang

John W Weidner

Typically Pt is alloyed with metals such as Ru, Sn, or Mo to provide a more CO-tolerant, high-performance proton exchange membrane fuel cell (PEMFC) anode. In this work, a layer of carbon-supported Ru is placed between the Pt catalyst and the anode flow field to form a filter. When oxygen is added to the fuel stream, it was predicted that the slow H2 kinetics of Ru in this filter would become an advantage compared to Pt and Pt:Ru alloy anodes, allowing a greater percentage of O2 to oxidize adsorbed CO to CO2. With an anode feed …


Oxidation Of Borides And Carbides With Y2o3 And Ta Additions, Salvador Manuel Rodriguez Jan 2012

Oxidation Of Borides And Carbides With Y2o3 And Ta Additions, Salvador Manuel Rodriguez

Open Access Theses & Dissertations

The study presented here describes an investigation of an oxidation scale of a fully-sintered Y2O3-ZrB2-TiC composite exposed in air at 1173K. Upon oxidation of the boride/carbide, a ZrO2-TiO2 was expected to form similar to the ZrO2-SiO2 dual scale of an oxidized ZrB2-SiC. The 47wt% Y2O3-38wt%ZrB2-16wt%TiC composite formed a dual scale consisting primarily of an Y2O3-ZrO2-TiC inner scale with an outer scale of ZrO2-TiO2-Y2O3.

The samples oxidized with a parabolic layer growth allowing the calculation of the effective diffusion coefficient indicating that the oxidation was controlled by oxygen ingress through primarily the ZrO2-Y2O3 phase. The oxygen potential between the inner layer …


Effect Of Titanium Dioxide Supports On The Activity Of Pt-Ru Toward Electrochemical Oxidation Of Methanol, Roderick E. Fuentes, Brenda L. García, John W. Weidner Jan 2011

Effect Of Titanium Dioxide Supports On The Activity Of Pt-Ru Toward Electrochemical Oxidation Of Methanol, Roderick E. Fuentes, Brenda L. García, John W. Weidner

Faculty Publications

TiO2and Nb-TiO2 were investigated as stable supports for Pt-Ru electrocatalysts towards methanol oxidation. X-ray photo-electron spectroscopy (XPS) data for all these TiO2-based supports show oxidation states of Ti4+, with no Ti3+, suggesting low electronic conductivity. However, the deposition of metal nanoparticles onto the supports at loadings of 60 wt% metal dramatically increased conductivity, making these electrodes (metal particles + support) suitable for electrochemistry even though the supports have low conductivity. For some of these TiO2-based supports, the activity of Pt-Ru towards methanol oxidation was excellent, even surpassing the activity …


Quantifying Individual Potential Contributions Of The Hybrid Sulfur Electrolyzer, John A. Staser, Maximilian B. Gorensek, John W. Weidner Jan 2010

Quantifying Individual Potential Contributions Of The Hybrid Sulfur Electrolyzer, John A. Staser, Maximilian B. Gorensek, John W. Weidner

Faculty Publications

The hybrid sulfur cycle has been investigated as a means to produce clean hydrogen efficiently on a large scale by first decomposing H2SO4 to SO2, O2, and H2O and then electrochemically oxidizing SO2 back to H2SO4 with the cogeneration of H2. Thus far, it has been determined that the total cell potential for the hybrid sulfur electrolyzer is controlled mainly by water transport in the cell. Water is required at the anode to participate in the oxidation of SO2 to H2SO4 …