Chemical Engineering Commons^™

Methodological Significance Of "Property-Activity Relationship" For Catalyst Studies, Jun-Tao Lu, Li Xiao, De-Li Wang, Yu-Bao Sun, Yan-Ge Suo, Lin Zhuang

Journal of Electrochemistry

Instead of attempting the structure-activity relationship (SAR), which is commonly regarded as the core problem for catalyst studies, this paper highlights the methodological significance of “property-activity relationship (PAR)”. The “property” here refers to an index （such as the adsorption energy of an intermediate） or a group of indexes reflecting the behavior of a catalyst which interacts with reactants or intermediates, and is a bridge between structure and activity. Because property is related to activity more directly than structure to activity, PAR should be simpler, less difficult and, therefore, more feasible to be accessed than SAR. Once the key property is …

Synthesis Of Spherical Ni3S4 By Solvothermal Method As Supercapacitor Electrodes, Qing-Na Huan, Li-Fang Jiao, Qing-Hong Wang, Hong-Mei Du, Jia-Qin Yang, Wen-Xiu Peng, Yi-Jing Wang, Hua-Tang Yuan

Journal of Electrochemistry

The Ni₃S₄ microspheres have been synthesized via a facile solvothermal method. The crystal structure and surface morphology are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microspherical Ni₃S₄ exhibits good electrochemical capacitance validated by electrochemical measurements. The specific capacities of 1120.6 F∙g^-1 at 0.5 A∙g^-1 and 433.4 F∙g^-1 at 4 A∙g^-1 with the capacitance retention of 89.37 % and 84.88 % were obtained after 1000 cycles, respectively. The electrochemical reaction is expected due to the transformation of Ni(OH)₂ and NiOOH based on the XRD, XPS and CV …

Cloning And Characterization Of Sas0754, A Hypothetical Protein From Community Associated Staphylococcus Aureus, Unknown Unknown

Symposium 2012

Community associated Staphylococcus aureus (strain MSSA476) is a gram positive cocci capable of infecting many different parts of the body and known to cause serious infections that can be fatal, such as bacterial arthritis and acute endocarditis. To find effective ways of fighting against CA-MRSA strains we must learn more about their ability to infect. The focus of this study was cloning and characterization of a protein referred to as SAS0754. The size of SAS0754 is 340 amino acids and the gene sequence is 1023 nucleotides. The hypothetical function of this protein is that it is an extracellular matrix binding …

A Convenient Synthesis Of 2,6-Dichlorohomonicotinic Acid, Chase Buchanan, Richard W. Fitch

Symposium 2012

In our synthetic efforts toward the alkaloid phantasmidine, we required a convenient source of the title compound. Herein, we describe a short synthesis of 2,6-dichlorohomonicotinic acid by direct allylation of 2,6-dichloropyridine with LDA/allyl chloride, followed by permanganate oxidation of the side chain [figure1]. Yields for the allylation are high, while permanganate oxidation required more adjustment. Successful conditions require the modest acidification of the mixture with acetic acid and cleanup by acid base workup. No chromatography is needed.

Convenient Parallel Synthesis Of Alkyl- And Aryl-S-Tert-Butyl Thiothers, Rebecca Norcross, Jessica Stanfield, Richard W. Fitch

Symposium 2012

While preparing novel cysteine derivatives as oxidation catalysts, we needed S-tert-butylcysteine. We also examined acid-promoted tert-butylation of thiols using tert-butanol as reagent and solvent. While cysteine and aminoethanethiol work well using tBuOH in 4M HCl, other thiols fail in the aqueous environment and aerobic conditions. We examined a variety of aliphatic and aromatic thiols in tBuOH with H2SO4 catalysis and found that argon sparging and the use of 1 eq of acid led to good yields in a parallel format.

Catalyst Studies With Implications On The Design And Fabrication Of Microreactors, Eric Snider

Honors Theses

Biodiesel, or fatty acid methyl ester (FAME), 'is a potential alternative, renewable fuel source to lessen foreign fuel dependency. Dr. Frank Jones' microreactor research group is investigating the use of microreactors to produce biodiesel. Microreactors can increase reaction rates, heat transfer, and lessen production costs due to their small size. The first generation of microreactors, coated with a nickel oxide (NiO) catalyst, has been developed and needs to be tested to determine their performance. Also, a catalyst study comparing NiO and platinum oxide (PtO2) will be performed to find the better catalyst for FAME production.

Photocatalytic Reactor Using Tio2 Thin Film On Quartz Tubes, Ram Mahipal Kouda

Graduate Theses and Dissertations

Photocatalysis process, as an environmental application is an advanced oxidation process with tremendous potential in the near future. Previously many researchers, have conducted photocatalysis in different reactor configuration using TiO2 slurry and thin film, using a UV light source, the constraints for these reactors are the need for the removal of TiO2 particles at the outlet stream in a slurry reactor and poor environment for the efficient use of TiO2 film using UV light, as the UV light penetration depth in water is about an inch.

Taking all this into consideration, we propose a design for reactor with efficient contact …

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Synthesis And Electrochemical Properties Of Lifeso4F/Graphene Composite As Cathode Material For Lithium-Ion Batteries, Wei Guo, Ya-Xia Yin, Li-Jun Wan, Yu-Guo Guo

Journal of Electrochemistry

The LiFeSO₄F was successfully synthesized from the reactions of FeSO₄∙xH₂O (x=1, 4, 7) with LiF in tetraethylene glycol media through a facile low temperature method. The structures and microscopic features of the products were characterized by XRD, SEM and TEM. TGA result shows the good thermal stability of the as-prepared LiFeSO₄F. No diffraction peaks of the FeSO₄ are observed in the as-prepared products with the starting material of either FeSO₄∙4H₂O or FeSO₄∙7H₂O, which should be ascribed to delaying the release of H_{2 …}

Ethanol Electrooxidation On Pt/Mo2/Cnts Catalysts, Yu-Long Cheng, Jie Sun, Ji-Gang Li, Li-Gong Zhang, Tian Zhou, Geng Chang, Zhong-Chao Dong

Journal of Electrochemistry

The ethanol electrooxidation behaviors on Pt/MO₂/CNTs（M=Sn, Ti, Ce）and Pt/CNTs catalysts in H₂SO₄ solutions were researched by cyclic voltammetry. It has revealed that the catalysts with the addition of metal oxides presented higher electrooxidation activity for ethanol, in particular, the Pt/CeO₂/CNTs catalyst showed the best activity for ethanol electrooxidation intermediate. The Pt/SnO₂/CNTs catalyst demonstrated the best ethanol electrooxidation activity when considering the synthetic effects of such parameters as the onset oxidation potential, peak current densities and total oxidation area.

Catalytic Activities Of Electrochemically Dealloyed Pt(Pd)-Cu Catalysts For Oxygen Reduction Reaction, Rui-Zhi Yang, Strasser Peter, Toney Michael

Journal of Electrochemistry

The electrochemically dealloyed Pt(Pd)-Cu catalysts were prepared by electrochemical dealloying of Cu₃Pt(Pd) and their catalytic activities toward oxygen reduction reaction (ORR) were studied in 0.1 mol·L^-1 HClO₄ . solutions. The structural features of the dealloyed Pt(Pd)-Cu were revealed by synchrotron-based anomalous X-ray diffraction (AXRD) and surface X-ray scattering (SXS) at an atomic scale. We established a relationship between the structure and the catalytic activity by comparing the ORR activity and the structure of dealloyed Cu₃Pt nanoparticles with similarly dealloyed Cu₃Pt thin films and Cu₃Pt(111). The enhancement in the activity of …

Template-Free Synthesis Of Porous Nio Hierarchical Structure For High Performance Supercapacitors, Yun Huang, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

A facile and template-free hydrothermal method is proposed to successfully synthesize porous NiO hierarchical structure, which is found to be assembled from ultrathin NiO nanosheets. As for electrochemical pseudocapacitor application, the obtained material exhibits not only high specific capacitances of 435 F·g^-1 at 20 mV·s^-1 and 367 F·g^-1 at 10 A·g^-1, but also holds a good electrochemical stability over 1000 cycles at a current rate of 20 mV·s^-1. These results suggest that the hierarchical structured porous NiO is a promising supercapacitor electrode material.

Electrochemical Reduction Of Co2 On Sn/Cu Electrodes, Chen-Chen Zhao, Jian-Wei Guo, Li Wang, Xiang-Ming He, Cheng Wang, Zhi-Xiang Liu

Journal of Electrochemistry

The Sn/Cu electrodes were prepared by electroplating method and their morphologies under different galvanization current densities were determined by SEM. In alkali, the effects of Sn/Cu electrodes on the activities towards hydrogen evolution and electrochemical reduction of CO₂ were investigated in alkaline solutions using a three-electrode system. These results indicated that the Sn/Cu electrodes prepared at 10 mA/cm² and 15 mA/cm² showed good activities, while that prepared at 15 mA/cm² was even better in activities. The synergetic structure of the Sn/Cu electrode to be beneficial to electrochemical reduction of CO₂ has been pointed out.

Electrochemical Properties Of The Keggin-Type Lacunary Heteropolysilicate Anion And Its Eectrocatalysis For H2O2 Reduction, Xi-Long Liu, Chun-Yan Wu, Fang Zhou, Hong-Sheng Liu, Ying-Jie Hua, Chong-Tai Wang, Xiao-Yang Liu

Journal of Electrochemistry

Electrochemical properties of the Keggin-type lacunary heteropolysilicate anion SiW₁₁O₃₉^8- (SiW₁₁) and its indirect electrocatalysis for H₂O₂ reduction in the supporting electrolyte containing 0.1 mol·L^-1 NaHSO₄ and Na₂SO₄ solutions were investigated using cyclic voltammetry, square wave voltammetry and alternating current impedance spectroscopy. Experimental results indicated that SiW₁₁ showed two pairs of reversible redox waves on the glassy carbon (GC) electrode in an acidic solution. The electron transfer number corresponding to the two pairs of waves was one, and the proton transfer number involved was two during …

Electrocatalytic Oxidation Of Ethanol On Ni-P-Tio2 Composite Coating Electrodes, Guang-Hui Hu, Hai-Xia Zeng, Zhi-Gang Wei, Zhan-Chang Pan, Shu-Guang Xie, Yan-Di Zou

Journal of Electrochemistry

The Ni-P-TiO₂ composite coating electrodes with different contents of TiO₂ particulates were prepared by electroless plating technique from Ni-P plating bath containing TiO₂ powders on brass. Cyclic voltammetry, linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were used to test the electrochemical performance of Ni-P-TiO₂/Cu electrodes. It was indicated that the Ni-P-TiO₂/Cu electrodes exhibited very strong electrocatalytic activity toward the oxidation of ethanol in alkaline medium at ambient temperature. The electrocatalytic activity of ethanol oxidation on the Ni-P-TiO₂ electrodes depended on the amounts of TiO₂ in the coatings. The …

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …

Electrochemical Preparation Of Nanostructural Pt-Ni And Pd-Ni Films For Ethanol Electro-Oxidation, Chen-Zhong Yao, Hui-Xuan Ma, Bo-Hui Wei

Journal of Electrochemistry

The Pt-Ni and Pd-Ni films were successfully prepared on Ti substrates by electrodeposition method. The porous Pt-Ni nanoflakes appeared to be uniform with the thickness of the slices about 10 ~ 20 nm. The porous Pd-Ni nanoparticles with a flower shape appeared to be uniform with the diameters of 50 ~ 60 nm. The XRD patterns also indicated that the Pd-Ni and Pt-Ni nanostructures have the poor crystallinity. The onset potentials of ethanol oxidation were negatively shifted to –0.74 V on Pt-Ni electrodes and –0.71 V on Pd-Ni electrodes, respectively. Addition of Ni could enhance catalytic activities and antitoxic properties …

Synthesis And Electrochemical Performance Of Xlifepo4·Yli3V2(Po4)3 Composites, Ping-Ping Ma, Zhi-Jian Liu, Jian-Hua Xia, Yu Chen, Pu Hu, Zhi-Chao Lu, Ding-Guo Xia

Journal of Electrochemistry

A series of xLiFePO₄·yLi₃V₂(PO₄)₃ composites were systematically synthesized through solid state reactions by variations in the proportions of LiFePO₄ and Li₃V₂(PO₄)₃. The properties of the prepared compounds were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The capacity of 162.7 mAh/g at 0.2 C rate was obtained with the relatively good cycle stability and good conductivity for 0.95LiFePO₄·0.05Li₃V₂(PO₄)₃ due to more uniformed distributed and smaller particle sizes.

Electrocatalytic Study Of Pseudomonas Aeruginosa Bte-1 Strain, Ping Zhou, En-Ren Zhang, Li Zhou, Guo-Wang Diao, Jun-Le Niu

Journal of Electrochemistry

The aim of the present study is to investigate the electrocatalytic activity of electricity-producing Pseudomonas aeruginosa BTE-1 strain under anaerobic conditions. Pseudomonas aeruginosa BTE-1 was inoculated into anaerobic three-electrode electrochemical cells, and the electrocatalytic activity was measured at poised potentials. HPLC and cyclic voltammetry were used to detect potential electron mediators in solutions. Experimental results showed that no detectable pyocyanine was excreted by P. aeruginosa BTE-1 strain in the anaerobic electrochemcial cells, and P. aeruginosa BTE-1 exhibited direct electrocatalytic activity through the formation of biofilm on the electrode surface which was induced by the electron transfer from the cells of …

Progress And Perspective Of Fuel Cell Technology, Ming Hou, Bao-Lian Yi

Journal of Electrochemistry

Fuel cell, a clean and high-efficiency electrochemical power source, has being paid much attention worldwide recent years. In this paper, the progress and perspective of fuel cell technology are elucidated in detail. Fuel cells have been applied in some special fields such as spacecraft, shuttle and submarines. However, in the areas of transportation, stationary station and portable power source, fuel cells are still under demonstration due to the durability and cost problems. The reliability and surrounding survivability of fuel cells should be enhanced in the special application. Meanwhile, the durability and cost of fuel cells are the main issues to …

Development Of Tailor-Designed Gold-Platinum Nanoparticles Binary Catalysts For Efficient Formic Acid Electrooxidation, Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof, Mohamed S. El-Deab Prof, Bahgat E. El-Anadouli Prof

Chemical Engineering

The modification of a glassy carbon (GC) electrode with platinum (PtNPs) and gold (AuNPs) nanoparticles is targeted to fabricate efficient anodes for the electrooxidation of formic acid (FA). A proper adjustment of the deposition sequence of PtNPs and AuNPs could eventually enhance the electrocatalytic activity of the electrode in such a way that suppresses the CO poisoning effect during FA oxidation. The highest catalytic activity is obtained at the Au/Pt/GC electrode (with PtNPs firstly deposited on the GC electrode followed by AuNPs). This superb enhancement is quantified by comparing the relative ratio of the direct vs. the indirect oxidation peaks …

Investigation Of Carbon Corrosion Resistance Of Cnt Containing Electrode, Diana Larrabee, William A. Rigdon, Eli Mcpherson, Joshua Sightler, Xinyu Huang

Faculty Publications

Carbon support corrosion is one of the major degradation mechanisms of polymer electrolyte membrane (PEM) fuel cell. Carbon oxidation occurs in PEM electrode and is accelerated at high potential created by adverse operating conditions and improper distribution of reactants and products [1, 2, 3]. Carbon corrosion can lead to the thinning of the electrode layer and severe performance degradation. The detailed mechanisms of carbon support corrosion induced performance loss are still not fully understood; it is believed that the following events contribute to the decay: (1) structural collapse of the porous electrode due to the loss of carbon; (2) carbon …

Application Of Electrospinning Technique In The Fabrication Of A Composite Electrode For Pemfc, Joshua Sightler, Eli Mcpherson, William A. Rigdon, Xinyu Huang

Faculty Publications

The Pt/C catalysts were mixed with carbon nanotube (CNT), Nafion™ dispersion and a fiber former, polymer poly-acrylic acid (PAA), to form an ink. The ink was deposited onto aluminum foil attached to a rotating collector via an electrospinning process. The ink composition, mixing procedure, and the E-spin parameters were studied for producing a uniform nanofiber mat on the aluminum substrate. The fiber-mat containing active catalyst ingredients was heat treated and decal transferred onto a Nafion membrane to form a membrane electrode assembly (MEA).

Application Of Thin Film Analysis Techniques And Controlled Reaction Environments To Model And Enhance Biomass Utilization By Cellulolytic Bacteria, Hsin-Fen Li

Theses and Dissertations--Chemical and Materials Engineering

Cellulose from energy crops or agriculture residues can be utilized as a sustainable energy resource to produce biofuels such as ethanol. The process of converting cellulose into solvents and biofuels requires the saccharification of cellulose into soluble, fermentable sugars. However, challenges to cellulosic biofuel production include increasing the activity of cellulose-degrading enzymes (cellulases) and increasing solvent (ethanol) yield while minimizing the co-production of organic acids. This work applies novel surface analysis techniques and fermentation reactor perturbations to quantify, manipulate, and model enzymatic and metabolic processes critical to the efficient production of cellulosic biofuels.

Surface analysis techniques utilizing cellulose thin film …

Microemulsion Preparation And Electrochemical Characterization Of Pt/C, Ptir/C Electrocatalysts, Ya-Ping Zeng, Sheng Sui

Journal of Electrochemistry

The Pt/C electrocatalysts were prepared by three different systems and the PtIr/C electrocatalysts were prepared with four different Ir contents. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), cyclic voltammetry (CV), potentiostatic and potentiodynamic polarizations measurements. The experimental results confirmed that the electrocatalyst particles prepared by the microemulsion method were well distributed on XC-72R supports with the active particle sizes of 5～10nm and good electrocatalysts activity. The Pt85Ir15/C electrocatalysts showed the highest overall electrochemical activity in unitized regenerative fuel cell.

Preparation And Characterization Of The Lani0.6Fe0.4O3-δ Cathode For Intermediate Temperature Solid Oxide Fuel Cell, Hang Liu, Bo Huang, Xin-Jian Zhu

Journal of Electrochemistry

The LaNi_0.6Fe_0.4O_3-δ as cathode material for intermediate temperature solid oxide fuel cell was prepared using a combustion synthesis technique. The X-ray diffraction (XRD) pattern showed that the single-phase LaNi_0.6Fe_0.4O_3-δ perovskite could be obtained after heat treatment at 600°C. The TEM and SEM images of the synthesized powders revealed that the grains were 50-100nm. According to the electrochemical impedance spectra (EIS), the polarization resistance of the symmetric cell LaNi_0.6Fe_0.4O_3-δ/ScSZ/LaNi_0.6Fe_0.4O_3-δ sintered at 1050°C was the smallest (0.70Ω·cm², 0.27Ω·cm^{2 …}

Dynamic Modeling And Characteristic Analysis Of Proton Exchange Membrane Fuel Cell, Qiu-Hong Jia, Ming Han, Bin Deng, Cai-Zhi Zhang

Journal of Electrochemistry

In this paper, a dynamic model of PEMFC is developed to estimate the dynamic performance of PEMFC by analyzing in detail the influence factors of voltage of PEMFC including various losses. The partial pressure of hydrogen and oxygen is obtained using the differential form of the ideal-gas equation in this model. The steady-state model is obtained by setting reasonable parameter values. The simulation results and experimental results have good consistency, which shows that the simulation model is correct, reasonable and effective. It analyzed the dynamic response characteristics of the output voltage and the partial pressure of hydrogen in condition of …

Preparation And Capacitance Characteristics Of Nickel Oxide Electrode With Mesh-Like Structure, Hui Xu, Zhen-Jun Peng, Dong-Hong Guo, Jun-Ling Li

Journal of Electrochemistry

The mesh-like structure of NiO electrode was obtained by first preparing the precursors via hydrothermal process using nickel sulfate and carbamide as reactants, sodium hexametaphosphate as a surfactant, and followed by calcination of the precursors at 400 ℃. The structure, morphology and capacitance characteristics of NiO electrode were characterized by XRD, SEM and constant current charge-discharge testing techniques. The effects of hydrothermal temperatures on the electrochemical properties of NiO electrode were investigated. The results showed that the better property of nickel oxide was obtained when the mole ratio of nickel to urea was 1:4 and the hydrothermal temperature was 140℃. …

Electrochemical Properties Of Tungstogermanate And Electrocatalysis Of H2O2 On Gew11Co/P-Opd/Gc Electrode, Li-Li Zhu, Jian-Ying Qu, Jue Wang, Hao-Yue Feng

Journal of Electrochemistry

The electrochemical properties of Co-substituted trimeric tungstogermanate containing Keggin fragments were studied. Cyclic voltammograms revealed two couples of reversible redox peaks on glassy carbon (GC) electrode in acid solutions. They corresponded to two-electron reductions accompanying by the additions of four protons and three protons, respectively, both were controlled by adsorption. The differences in the peak potentials of 2-electron-4-proton and 2-electron-3-proton reactions were 31 mV and 35 mV, respectively..Furthermore, the tungstogermanate (GeW11Co) modified GC electrode with functionalization by poly(o-phenylenediamine) (P-oPD) was prepared readily by electropolymerization. The GeW11Co/P-oPD/GC electrode could electrocatalyze the reduction of hydrogen peroxide, which showed good stability and quick …

Indirect Electrochemical Reduction And Cotton Dyeing Process In Fe(Ⅲ)-Oxalate-Calcium Gluconate System, Qing-Zhi Wang, Wei Wang

Journal of Electrochemistry

The electrochemical behavior and possible reaction mechanism in Fe(Ⅲ)-oxalate-calcium gluconate system were studied by cyclic voltammetry. The results showed that Fe(Ⅱ)-gluconate was the final reductant. The reduction time, the working voltage and the cathode area influenced the current efficiency. The high current efficiency of 89% for the indirect electrochemical reduction of Vat Scarlet R could be achieved with reduction time of 10 min, working voltage of 4 V and cathode area of 40 cm² in Fe(Ⅲ)-oxalate-calcium gluconate system.