Catalysis and Reaction Engineering Commons^™

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 …

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 …

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 …

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.

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.

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 …

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 …

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.

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℃. …

Evaluation Of Cathode Materials For Low Temperature (500-700c) Solid Oxide Fuel Cells, Alexander M. Lassman

Master's Theses

Solid oxide fuel cells (SOFC) have gained a great deal of interest, due to their potential for high efficiency power generation and ability to utilize hydrogen fuel, as well as various hydrocarbon-based fuels. A recent trend in SOFC development has been towards lower operating temperatures (500-700°C), which can substantially reduce the cost and complexity of the system. This thesis presents an investigation into state of the art Ba- and La- based cathode materials for use in low temperature (500-700°C) solid oxide fuel cells.

Synthesis of A-site deficient [A=0.97] Ba_0.5Sr_0.5Co_0.8Fe_0.2O₃ (BSCF) was …

Electrochemical Performance Of Tin Dioxide/Carbon Xerogel Composites As Anode Materials For Lithium-Ion Batteries, Xiao-Jing Liu, Lin-Lin Qin, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The tin dioxide/carbon xerogel composites were synthesized by using vacuum infiltration method. Structural characterization and morphology of the composites were investigated by using XRD, TEM and SEM techniques. BET test was performed to determine the pore size distributions of carbon xerogels and the composites. The results showed that the nano-sized SnO₂ particles (5~10 nm) were encapsulated in the pores of carbon xerogels. During the electrochemical tests the SnO₂ in the composites exhibited capacity retention of 61.9% after 100 cycles of charge-discharge tests at 100 mA/g.

Synthesis Of Limnpo4/C Used As Cathode Material For Lithium Ion Batteries, Xin Yang, Xue-Wu Liu, Gui-Chang Liu, Zhi-Cong Shi, Xin Li, Guo-Hua Chen

Journal of Electrochemistry

The LiMnPO₄/C composites were prepared using a solid-state reaction with addition of the resorcinol formaldehyde resin as the carbon source. The effects of reaction temperature and time on the crystal structure, morphology and electrochemical properties of the LiMnPO₄/C composites were investigated. The results show that the best performance was achieved with the LiMnPO₄/C composites synthesized at 600 ^oC for 12 h which had the particle sizes about 100~200 nm. The initial discharge capacities were 121.6 mAh·g^-1 at 0.02C, 110 mAh·g^-1 at 0.1C and more than 60 mAh·g^-1 at 1C. An …

Synthesis And Electrochemical Behaviors Of Li2Coxmn1-XSio4 As A Cathode Material For Lithium-Ion Batteries, Lin Wang, Dong-Ping Lv, Yong Yang

Journal of Electrochemistry

We have successfully synthesized Li₂Co_xMn_1-xSiO₄/C (x=0, 0.1, 0.3, 0.5, 1)/C composites using hydrothermal assisted sol-gel process and ball-milling method. The results of X-ray diffraction show that the solid solutions of Li₂Co_xMn_1-xSiO₄ can be achieved when x≤0.3. The initial capacities increase from 70 mAh·g^-1 of Li₂MnSiO₄/C to 105 mAh·g^-1 of Li₂Co_0.3Mn_0.7SiO₄/C. Cyclic Voltammetry (CV) curves show that the replacement of Mn with Co can reduce the electrochemical polarization, making the insertion-extraction reaction …

Applied Control Strategies At A Cogeneration Plant, Joseph William Burns

Master's Theses

The purpose of this paper is to demonstrate the effectiveness of “classical strategies for dynamic control” on authentic cogeneration processes. These strategies are applied to several processes at the University of Connecticut’s cogeneration plant. Case studies of their applications are presented in this paper. Strategies that are applied include the following:

1) The classical SISO feedback structure

2) The First Order Plus Dead Time (FOPDT) process model

3) The Internal Model Control (IMC) correlations for PI controller tuning

4) Static feed forward with feedback trim

5) Cascade Control

Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan

Journal of Electrochemistry

A simple and efficient electrochemical route was developed for the synthesis of flaked spindle-like CuO nanocrystals using aqueous electrolyte and Cu sacrificial anode (graphite as the cathode) in an undivided cell at a constant potential mode under room temperature. The morphologies, structure and component of CuO nanocrystals obtained were characterized by SEM, XRD, respectively. Flaked spindle-like CuO nanocrystals were successfully used to modify a GC electrode to detect H₂O₂ with cyclic voltammetry (CV) and amperometric (AC).The results showed that products were pure monoclinic CuO nanocrystals. The linear range for the determination of hydrogen peroxide is from 1.0 …

Preparation And Electrocatalytic Activity Of The Pt/Wc/Tio2 Composites, Chun-An Ma, Bin Yu, Mei-Qin Shi, Xiao-Ling Lang

Journal of Electrochemistry

TiO₂ was used as the support for preparation of Pt/WC/TiO₂ composite catalyst. The composites were characterized by XRD, SEM and TEM methods. The electrocatalytical activity of Pt/WC/TiO₂ composite for oxidation of methanol was investigated by cyclic voltammetry. Pt/WC/TiO₂ exhibited higher activity compared with that of Pt/TiO₂ and Pt/WC composite catalysts. Based on this we discussed the effects of crystal phases of TiO₂ on the electrocatalytical activity of Pt/WC/TiO₂ composite catalyst.

Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen

Journal of Electrochemistry

CO₂ reduction on Cu(111) single crystal surfaces was studied using DFT calculations on the reaction energies and the minimum energy paths. The results indicated that the possible reaction paths for CO₂ reduction on Cu(111) surface are CO₂(g) + H* → COOH* → (CO +OH)*, (CO + H)* → CHO*, CHO + H → CH₂O* → (CH_2⁺O)*, CH₂* + 2H* → CH₄ or 2CH₂* → C₂H₄. On Cu(111) surface, the reaction rate is controlled by steps of CH₂O* → (CH_{2 …}

Study On Direct Electro-Oxidation Of Anisaldehyde, Lin-Lin Wu, Ying-Hong Zhu, Shan-Shan Li, Hong-Yan Zeng, Chun-An Ma

Journal of Electrochemistry

The oxidation of anisole on Pt electrode was investigated by cyclic voltammery and constant potential electrolysis. The influence of scan rates, substrate concentration, supporting electrolytes and solvent were considered . The results show that the electro-oxidation process of anisole was irreversible. In this research the sulfuric acid was the best supporting electrolytes and acetone was the best solvent, and the process was controlled by diffusion . The product of constant potential electrolysis was charactered by GC-MS .The results show that the main products was anisaldehyde, and the selectivity was up to 66.5% when using acetone as solvent.

Comparison Of Catalytic Performance On Different Materials Supported Pd Catalysts For Formic Acid Oxidation, Su-Dong Yang, Yan-Yu Liang, Zhu-Liang Wen, Qi-Jun Song, Xiao-Gang Zhang

Journal of Electrochemistry

Graphite oxide (GO) was prepared from by Hummers method. Then the graphene nanosheets supporting Pd catalysts were prepared by a single-step chemical reduction method. The electrocatalytic performance for formic acid oxidation of the prepared Pd/graphene composite was studied as an electrode material in comparison with the composite catalysts based on the other carbons (MWCNTs, SWCNTs, and Vulcan XC-72 carbon black). X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements indicated that the Pd nanoparticles were well dispersed on the surface of the graphene nanosheets with a small particle size. The electrocatalytic oxidation of formic acid was studied by electrochemically active …

Anode Electrodeposition Of Ti/Mno2 Electrode And Electrocatalytic Oxidization Properties Of Phenol Degradation, Ye Chen, Wen-Li Zhao, Qing Wen

Journal of Electrochemistry

Ti-base manganese dioxide (Ti/MnO₂) electrode was prepared by anodically electrodeposition technology in this paper. The structure of the electrode, the microstructure of the electrode surface and the element composition of the electrode were analyzed by XRD, SEM and EDS. The preparation process parameters of the electrode were studied in detail with the help of the V~logi curve and phenol degradation curve. The Ti/MnO₂ electrode was anodically electrodeposited at current density 4mA•cm^-2, the Mn^{2 +} ions concentration 0.5mol•L^-1 and temperature70℃. The V~logi curve and phenol degradation curve were used to evaluate electrocatalytic oxidization properties …

Electrochemical Capacitive Performance Of Mesoporous Carbon Based Co-Ni Oxides, Zhen-Sheng Yang, Ling-Bin Kong, Li Deng, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

By using defects on the surface of CMK-3 served as nucleation center, Co_0.25Ni_0.75 oxide/C composite was successfully prepared through a simple chemical co-precipitation method. Characterization was carried by using X-ray diffraction, BET and scanning electron microscopy. Results showed that a perfect mesoporous network of interconnected nanoflakes was obtained for Co_0.25Ni_0.75 oxide/C composite and, this material has a less crystallization, interconnected nanoflakes network structure and a narrow mesoporous distribution at about 3~4 nm. The highly dispersed and loosely packed Co_0.25Ni_0.75 oxide/C composite possessed good electrochemical accessibility and fast diffusion rate of OH …

Synthesis Of Mesoporous Nickel Oxide For Supercapacitor Application, Xuan-Xuan Chen, Zhen-Zhen Zhao, Deng-Chao Wang, Zhong-Jie Huang, Wen-Bin Ni, Li Yu, Jian-Wei Zhao

Journal of Electrochemistry

Mesoporous nickel oxide has been synthesized by calcining metal-organic coordination precursor.Transmission electron microscopy and BET test showed that the prepared NiO had a regular morphology and displayed a narrow size distribution.Electrochemical tests revealed that such mesoporous NiO had a specific capacity of 72 F·g^-1 at the current of 2.0 A·g^-1.Futhermore,the material showed excellent cycle-life stability.There was no degradation of capacitance after 1000 cycles.

A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi

Journal of Electrochemistry

Titanium-supported nanoporous palladium electrode(nanoPd /Ti) was prepared by a hydrothermal process in the presence of the ligand EDTA and using formaldehyde as reducing agent.SEM images showed that the size of Pd particles was about 60 nm and the Pd particles were connected with each other to form a three-dimensional network structure.Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were applied to evaluate the electrocatalytic activity of the nanoPd/Ti electrode towards methanol oxidation in alkaline solution.CV results showed that the nanoPd /Ti electrode presented high anodic peak densities and a low onset potential for methanol oxidation.Also nanoPd /Ti electrode showed excellent CO tolerance …

Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng

Journal of Electrochemistry

The electrochemical behavior and electrocatalytic oxidation of hydrazine on rutin multiwall carbon nanotubes modified glassy carbon electrode were studied by cyclic voltammetry.The experimental results indicated that the electrode exhibits good electrocatalytic activity to hydrazine at a reduced oxidation potential of 262 mV.The amperometric response of the modified electrode showed linear increase after successive addition of hydrazine in the concentration range of 2.5×10^-6~1.0×10^-4 mol·L-1 with a detection limit of 5×10^-7 mol·L^-1.