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Articles 1891 - 1920 of 2359

Full-Text Articles in Engineering

Enhanced Dielectric Properties In Single Crystal-Like Bifeo3 Thin Films Grown By Flux-Mediated Epitaxy, S.-H. Lim, M. Murakami, J. H. Yang, S.-Y. Young, Jason R. Hattrick-Simpers, M. Wuttig, L. G. Salamanca-Riba, I. Takeuchi Jan 2008

Enhanced Dielectric Properties In Single Crystal-Like Bifeo3 Thin Films Grown By Flux-Mediated Epitaxy, S.-H. Lim, M. Murakami, J. H. Yang, S.-Y. Young, Jason R. Hattrick-Simpers, M. Wuttig, L. G. Salamanca-Riba, I. Takeuchi

Faculty Publications

We have fabricated single crystal-like BiFeO3 (BFO) thin films by flux-mediated epitaxy using pulsed laser deposition(PLD). The Bi–Cu–O flux composition and its thickness were optimized using composition spread, thickness gradient, and temperature gradient libraries. The optimized BFO thin films grown with this technique showed larger grain size of ∼2μm and higher dielectric constant in the range of 260–340 than those for standard PLD grown films. In addition, the leakage current density of the films was reduced by two orders of magnitude compared to that of standard PLD grown films.

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Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu Jan 2008

Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu

Faculty Publications

Multilayered solid structures made of isotropic, transversely isotropic, or general anisotropic materials are frequently used in aerospace, mechanical, and civil structures. Ultrasonic fields developed in such structures by finite size transducers simulating actual experiments in laboratories or in the field have not been rigorously studied. Several attempts to compute the ultrasonic field inside solid media have been made based on approximate paraxial methods like the classical ray tracing and multi-Gaussian beam models. These approximate methods have several limitations. A new semianalytical method is adopted in this article to model elastic wave field in multilayered solid structures with planar or nonplanar …

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The Role Of Filler-Matrix Interaction On Viscoelastic Response Of Biomimetic Nanocomposite Hydrogels, Alireza S. Sarvestani, Xuezhong He, Esmaiel Jabbari Jan 2008

The Role Of Filler-Matrix Interaction On Viscoelastic Response Of Biomimetic Nanocomposite Hydrogels, Alireza S. Sarvestani, Xuezhong He, Esmaiel Jabbari

Faculty Publications

The effect of a glutamic acid (negatively charged) peptide (Glu6), which mimics the terminal region of the osteonectin glycoprotein of bone on the shear modulus of a synthetic hydorgel/apatite nanocomposite, was investigated. One end of the synthesized peptide was functionalized with an acrylate group (Ac-Glu6) to covalently attach the peptide to the hydrogel phase of the composite matrix. The addition of Ac-Glu6 to hydroxyapatite (HA) nanoparticles (50 nm in size) resulted in significant reinforcement of the shear modulus of the nanocomposite (~100% increase in elastic shear modulus). The reinforcement effect of the Glu6 peptide, a sequence in the terminal region …

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Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White Jan 2008

Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White

Faculty Publications

Lithium-ion pouch cells were cycled at five different temperatures (5, 15, 25, 35, and 45°C ), and rate capability studies were performed after every hundred cycles. The data were used with a simple physics-based model to estimate parameters that capture the capacity fade in the cell, with cycling. The weight of active material within each electrode was estimated as a function of time, using rate capability data at the C/33 rate. The C-rate for these cells is 1.656 A. The capacity fade due to the loss of active material and that due to the loss of cyclable lithium …

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Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White Jan 2008

Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White

Faculty Publications

A thermal model for a lithium-ion cell is presented and used to predict discharge performance at different operating temperatures. The results from the simulations are compared to experimental data obtained from lithium-ion pouch cells. The model includes a set of parameters (and their concentration and temperature dependencies) that has been obtained for a lithium-ion cell composed of a mesocarbon microbead anode, LiCoO2 cathode in 1 M LiPF6 salt, in a mixture of ethylene carbonate, propylene carbonate, ethyl-methyl carbonate, and diethyl carbonate electrolyte. The parameter set was obtained by comparing the model predictions to the experimental discharge profiles obtained …

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Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White Jan 2008

Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White

Faculty Publications

An analytical expression to predict the impedance response of a dual insertion electrode cell (insertion electrodes separated by an ionically conducting membrane) is presented. The expression accounts for the reaction kinetics and double-layer adsorption processes at the electrode-electrolyte interface, transport of electroactive species in the electrolyte phase, and insertion of species in the solid phase of the insertion electrodes. The accuracy of the analytical expression is validated by comparing the impedance response predicted by the expression to the corresponding numerical solution. The analytical expression is used to predict the impedance response of a lithium-ion cell consisting of a porous LiCoO …

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A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White Jan 2008

A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White

Faculty Publications

A mathematical model is presented for a complete lithium–sulfur cell. The model includes various electrochemical and chemical (precipitation) reactions, multicomponent transport phenomena in the electrolyte, and the charge transfer within and between solid and liquid phases. A change in the porosity of the porous cathode and separator due to precipitation reactions is also included in the model. The model is used to explain the physical reasons for the two-stage discharge profiles that are typically obtained for lithium–sulfur cells.

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). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li Dec 2007

). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li

Faculty Publications

Relation between the elastic modulus and the diameter (D) of ZnOnanowires was elucidated using a model with the calculated ZnOsurface stresses as input. We predict for ZnOnanowires due to surface stress effect: (1) when D>20nm, the elastic modulus would be lower than the bulk modulus and decrease with the decreasing diameter, (2) when 20nm>D>2nm, the nanowires with a longer length and a wurtzite crystal structure could be mechanically unstable, and (3) when D<2nm, the elastic modulus would be higher than that of the bulk value and increase with a decrease in nanowire diameter.

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Are There Rearrangement Hotspots In The Human Genome?, Max A. Alekseyev, Pavel A. Pevzner Nov 2007

Are There Rearrangement Hotspots In The Human Genome?, Max A. Alekseyev, Pavel A. Pevzner

Faculty Publications

In a landmark paper, Nadeau and Taylor [18] formulated the random breakage model (RBM) of chromosome evolution that postulates that there are no rearrangement hotspots in the human genome. In the next two decades, numerous studies with progressively increasing levels of resolution made RBM the de facto theory of chromosome evolution. Despite the fact that RBM had prophetic prediction power, it was recently refuted by Pevzner and Tesler [4], who introduced the fragile breakage model (FBM), postulating that the human genome is a mosaic of solid regions (with low propensity for rearrangements) and fragile regions (rearrangement hotspots). However, the rebuttal …

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Wireless Power Transmission To A Buried Sensor In Concrete, Khan M.Z. Shams, Mohammod Ali Nov 2007

Wireless Power Transmission To A Buried Sensor In Concrete, Khan M.Z. Shams, Mohammod Ali

Faculty Publications

The feasibility of sending wireless power to a buried sensor antenna within concrete was studied. a receive patch rectenna with 75.8% conversion efficiency was designed for operation at 5.7 GHz. The received DC power at the rectenna was measured within dry and wet concrete samples with various cover thicknesses and air-gaps. For the rectenna buried within 30 mm of the concrete, the received DC power was 10.37 mW, which was, about 70% of the received DC power in free-space.

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Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li Oct 2007

Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li

Faculty Publications

Nanoindentation in conjunction with piezoresponse force microscopy was used to study domain switching and to measure the mechanical properties of individual ferroelectric domains in a tetragonal BaTiO3 single crystal. It was found that nanoindentation has induced local domain switching; the a and c domains of BaTiO3 have different elastic moduli but similar hardness.Nanoindentationmodulus mapping on the a and c domains further confirmed such difference in elasticity. Finite element modeling was used to simulate the von Mises stress and plastic strain profiles of the indentations on both a and c domains, which introduces a much higher stress level than …

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Edge Grouping Combining Boundary And Region Information, Joachim S. Stahl, Song Wang Oct 2007

Edge Grouping Combining Boundary And Region Information, Joachim S. Stahl, Song Wang

Faculty Publications

This paper introduces a new edge-grouping method to detect perceptually salient structures in noisy images. Specifically, we define a new grouping cost function in a ratio form, where the numerator measures the boundary proximity of the resulting structure and the denominator measures the area of the resulting structure. This area term introduces a preference towards detecting larger-size structures and, therefore, makes the resulting edge grouping more robust to image noise. To find the optimal edge grouping with the minimum grouping cost, we develop a special graph model with two different kinds of edges and then reduce the grouping problem to …

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Silicon Dioxide-Encapsulated High-Voltage Algan/Gan Hfets For Power-Switching Applications, N. Tipirneni, V. Adivarahan, Grigory Simin, Asif Khan Sep 2007

Silicon Dioxide-Encapsulated High-Voltage Algan/Gan Hfets For Power-Switching Applications, N. Tipirneni, V. Adivarahan, Grigory Simin, Asif Khan

Faculty Publications

In this letter, new approach in achieving high breakdown voltages in AlGan/GaN heterostructure field-effect transistors (HFETs) by suppressing surface flashover using solid encapsulation material is presented. Surface flashover in III-Nitride-based HFETs limits the operating voltages at levels well below breakdown voltages of GaN. This premature gate-drain breakdown can be suppressed by immersing devices in high-dielectric-strength liquids (e.g., Fluorinert); however, such a technique is not practical. In this letter, AlGan/GaN HFETs encapsulated with PECVD-deposited SiO2 films demonstrated breakdown voltage of 900 V, very similar to that of devices immersed in Fluorinert liquid. Simultaneously, low dynamic ON-resistance of 2.43 m Omega. cm(2) …

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Localization With Limited Sensing, Jason M. O'Kane, Steven M. Lavalle Aug 2007

Localization With Limited Sensing, Jason M. O'Kane, Steven M. Lavalle

Faculty Publications

Localization is a fundamental problem for many kinds of mobile robots. Sensor systems of varying ability have been proposed and successfully used to solve the problem. This paper probes the lower limits of this range by describing three extremely simple robot models and addresses the active localization problem for each. The robot, whose configuration is composed of its position and orientation, moves in a fully-known, simply connected polygonal environment. We pose the localization task as a planning problem in the robot's information space, which encapsulates the uncertainty in the robot's configuration. We consider robots equipped with: 1) angular and linear …

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Adaptive Control Strategy For Active Power Sharing In Hybrid Fuel Cell/Battery Power Sources, Zhenhua Jiang, Lijun Gao, Roger A. Dougal Jun 2007

Adaptive Control Strategy For Active Power Sharing In Hybrid Fuel Cell/Battery Power Sources, Zhenhua Jiang, Lijun Gao, Roger A. Dougal

Faculty Publications

Hybrid systems composed of fuel cells and batteries combine the high energy density of fuel cells with the high power density of batteries. A dc/dc power converter is placed between the fuel cell and the battery to balance the power flow between them and greatly increase the peak output power of the hybrid. This paper presents an adaptive control strategy for active power sharing in the hybrid power source. This control strategy can adjust the output current setpoint of the fuel cell according to the state-of-charge (or voltage) of the battery, and is applicable in two topologies of active fuel …

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Fpga Acceleration Of Gene Rearrangement Analysis, Jason D. Bakos Apr 2007

Fpga Acceleration Of Gene Rearrangement Analysis, Jason D. Bakos

Faculty Publications

In this paper we present our work toward FPGA acceleration of phylogenetic reconstruction, a type of analysis that is commonly performed in the fields of systematic biology and comparative genomics. In our initial study, we have targeted a specific application that reconstructs maximum-parsimony (MP) phylogenies for gene-rearrangement data. Like other prevalent applications in computational biology, this application relies on a control-dependent, memory-intensive, and non-arithmetic combinatorial optimization algorithm. To achieve hardware acceleration, we developed an FPGA core design that implements the application's primary bottleneck computation. Because our core is lightweight, we are able to synthesize multiple cores on a single FPGA. …

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Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal Mar 2007

Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal

Faculty Publications

No abstract provided.

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A Reconfigurable Stacked Microstrip Patch Antenna For Satellite And Terrestrial Links, Mohammod Ali, Abu T.M. Sayem, Vijay K. Kunda Mar 2007

A Reconfigurable Stacked Microstrip Patch Antenna For Satellite And Terrestrial Links, Mohammod Ali, Abu T.M. Sayem, Vijay K. Kunda

Faculty Publications

A reconfigurable stacked microstrip patch antenna is proposed. The antenna operates at an upper frequency f(u) with a broadside pattern, 7.5-dBi right-hand circularly polarized gain, and 15.8% bandwidth. At a lower frequency f(1), the antenna operates as a planar inverted-F antenna (7.3% bandwidth and 3.9-dBi peak gain) with the main beam directed close to the horizon. Switching between the two regimes of operation is achieved using p-i-n diodes. antenna operation in the upper frequency hand is suitable for low-earth-orbit or medium-earth-orbit satellite communications, and in the lower frequency band, the antenna is useful for terrestrial land-mobile or other wireless applications.

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Lightweight Error Correction Coding For System-Level Interconnects, Jason D. Bakos, Donald M. Chiarulli, Steven P. Levitan Mar 2007

Lightweight Error Correction Coding For System-Level Interconnects, Jason D. Bakos, Donald M. Chiarulli, Steven P. Levitan

Faculty Publications

"Lightweight hierarchical error control coding (LHECC)" is a new class of nonlinear block codes that is designed to increase noise immunity and decrease error rate for high-performance chip-to-chip and on-chip interconnects. LHECC is designed such that its corresponding encoder and decoder logic may be tightly integrated into compact, high-speed, and low-latency I/O interfaces. LHECC operates over a new channel technology called multi-bit differential signaling (MBDS). MBDS channels utilize a physical-layer channel code called "N choose M (nCm)" encoding, where each channel is restricted to a symbol set such that half of the bits in each symbol are set to one. …

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Threshold Power Of Canonical Antennas For Inducing Sar At Compliance Limits In The 300-3000 Mhz Frequency Range, Mohammod Ali, Mark G. Douglas, Abu T.M. Sayem, Antonio Faraone, Chung-Kwang Chou Feb 2007

Threshold Power Of Canonical Antennas For Inducing Sar At Compliance Limits In The 300-3000 Mhz Frequency Range, Mohammod Ali, Mark G. Douglas, Abu T.M. Sayem, Antonio Faraone, Chung-Kwang Chou

Faculty Publications

A study of the specific absorption rate (SAR) in an exposed body induced by canonical antennas is presented, with the aim of determining an upper bound for the antenna transmit power that demonstrates that a product is inherently compliant with internationally accepted radio frequency (RF) exposure limits. Starting from the fundamental limits in antenna quality factor (Q) and the corresponding bandwidth, several antenna sizes are selected, and their SAR distributions are computed using the method of moments (MoM) and finite-difference time domain (FDTD) method in the frequency range 300-3000 MHz. The threshold powers are then determined, below which the peak …

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Iii Finishing, Lapping, Honing And Polishing: Processes, Characterisation And Novel Techniques-Experimental Research On Ultra-Smooth Surface Polishing Based On Two-Dimensional Vibration Of Liquid, Zhong Ning Guo, X. Z. Huang, Z. G. Huang, Z. Q. Yu, T. M. Yue, Wing Bun Lee Jan 2007

Iii Finishing, Lapping, Honing And Polishing: Processes, Characterisation And Novel Techniques-Experimental Research On Ultra-Smooth Surface Polishing Based On Two-Dimensional Vibration Of Liquid, Zhong Ning Guo, X. Z. Huang, Z. G. Huang, Z. Q. Yu, T. M. Yue, Wing Bun Lee

Faculty Publications

No abstract provided.

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In-Situ Optimized Pwas Phased Arrays For Lamb Wave Structural Health Monitoring, Lingyu Yu, Victor Giurgiutiu Jan 2007

In-Situ Optimized Pwas Phased Arrays For Lamb Wave Structural Health Monitoring, Lingyu Yu, Victor Giurgiutiu

Faculty Publications

No abstract provided.

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Simulation Of The Oxygen Reduction Reaction At An Rde In 0.5 M H2So4 Including An Adsorption Mechanism, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White Jan 2007

Simulation Of The Oxygen Reduction Reaction At An Rde In 0.5 M H2So4 Including An Adsorption Mechanism, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White

Faculty Publications

Oxygen reduction on the surface of a rotating disk electrode (RDE) in 0.5 M H2SO4 is simulated by including mass transfer, adsorption, and charge transfer. A generalized model for the adsorption and reaction of several species is introduced. The oxygen reduction reaction is simulated as a limiting case where oxygen is the only species adsorbed, and oxygen reduction is the only reaction that takes place on the surface of the electrode. The model is based on the Nernst–Planck equations for mass transfer and the Butler–Volmer equation for electrochemical kinetics. The simulated polarization curves capture the change in …

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Exafs Characterization Of Dendrimer‐Derived Pt/Γ‐Al2O3, A. Siani, Oleg S. Alexeev, Christopher T. Williams, Harry J. Ploehn, Michael D. Amiridis Jan 2007

Exafs Characterization Of Dendrimer‐Derived Pt/Γ‐Al2O3, A. Siani, Oleg S. Alexeev, Christopher T. Williams, Harry J. Ploehn, Michael D. Amiridis

Faculty Publications

The various steps involved in the preparation of a Pt/γ‐Al2O3 material using hydroxyl‐terminated generation four (G4OH) PAMAM dendrimers as templates were monitored by EXAFS. The results indicate that Cl ligands in the Pt precursors (H2PtCl6 and K2PtCl4) were partially replaced by aquo ligands upon hydrolysis to form [PtCl3(H2O)3]+ and [PtCl2(H2O)2] species. After interaction of such species with G4OH, Cl ligands from the first coordination shell of Pt were further replaced by nitrogen atoms from the dendrimer interior, …

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Modeling Li/CfX-Svo Hybrid-Cathode Batteries, Parthasarathy M. Gomadam, Donald R. Merritt, Erik R. Scott, Craig L. Schmidt, Paul M. Skarstad, John W. Weidner Jan 2007

Modeling Li/CfX-Svo Hybrid-Cathode Batteries, Parthasarathy M. Gomadam, Donald R. Merritt, Erik R. Scott, Craig L. Schmidt, Paul M. Skarstad, John W. Weidner

Faculty Publications

A mathematical model is developed that predicts the voltage-capacity behavior of a primary lithium battery containing a hybrid cathode, which combines the high energy density of carbon monofluoride (CFx) and the higher power density of silver vanadium oxide (SVO). The model is developed using material balances and kinetic expressions for each material, extracting kinetic and thermodynamic parameters from data collected on CFx and SVO batteries, and then integrating this information into a hybrid system. The full model is validated by comparing simulations to experimental data on Li/CFx-SVO hybrid-cathode batteries of various designs and for a …

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Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov Jan 2007

Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov

Faculty Publications

A process was developed to synthesize ruthenium-based chelate (RuNx) electrocatalysts for the oxygen reduction reaction, using RuCl3 and propylene diammine as the Ru and N precursors, respectively. High-temperature pyrolysis has a critical role in the formation of the catalytic Ru–N sites for oxygen reduction. The RuNx catalyst modified in the presence of nitrogen-containing organic exhibited comparable catalytic activity and selectivity for oxygen reduction to the carbon-supported Pt catalyst in acidic media. The catalyst generates less than 2% hydrogen peroxide during oxygen reduction.

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Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov Jan 2007

Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov

Faculty Publications

A pulse electrodeposition method of preparing thin platinum catalyst layers for polymer electrolyte membrane fuel cell (PEMFC) cathodes has been developed through surface activation of the gas diffusion layer (GDL) by a wetting agent. The performance of the catalyst layer was optimized by wetting agent type, immersion time in the wetting agent, and pulse deposition parameters such as total charge density, peak current density, and duty cycle ratio. The Toff time played a more important role than the Ton time in determining the electrode characteristics such as high concentration of Pt, smaller particle size, and loading. Pt cathodes …

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Whole Genome Duplications And Contracted Breakpoint Graphs, Max A. Alekseyev, Pavel A. Pevzner Jan 2007

Whole Genome Duplications And Contracted Breakpoint Graphs, Max A. Alekseyev, Pavel A. Pevzner

Faculty Publications

The genome halving problem, motivated by the whole genome duplication events in molecular evolution, was solved by El-Mabrouk and Sankoff in the pioneering paper [SIAM J. Comput., 32 (2003), pp. 754–792]. The El-Mabrouk–Sankoff algorithm is rather complex, inspiring a quest for a simpler solution. An alternative approach to the genome halving problem based on the notion of the contracted breakpoint graph was recently proposed in [M. A. Alekseyev and P. A. Pevzner, IEEE/ACM Trans. Comput. Biol. Bioinformatics, 4 (2007), pp. 98–107]. This new technique reveals that while the El-Mabrouk–Sankoff result is correct in most cases, it does not hold in …

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Colored De Bruijn Graphs And The Genome Halving Problem, Max A. Alekseyev, Pavel A. Pevzner Jan 2007

Colored De Bruijn Graphs And The Genome Halving Problem, Max A. Alekseyev, Pavel A. Pevzner

Faculty Publications

Breakpoint graph analysis is a key algorithmic technique in studies of genome rearrangements. However, breakpoint graphs are defined only for genomes without duplicated genes, thus limiting their applications in rearrangement analysis. We discuss a connection between the breakpoint graphs and de Bruijn graphs that leads to a generalization of the notion of breakpoint graph for genomes with duplicated genes. We further use the generalized breakpoint graphs to study the Genome Halving Problem (first introduced and solved by Nadia El-Mabrouk and David Sankoff). The El-Mabrouk-Sankoff algorithm is rather complex, and, in this paper, we present an alternative approach that is based …

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Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov Jan 2007

Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov

Faculty Publications

A procedure was developed to synthesize a platinum–cobalt (Pt–Co) alloy electrocatalyst for oxygen reduction using Co/C composite as a support. The Pt–Co/C catalysts were synthesized through: (i) chemical oxidation of carbon black, (ii) Co deposition on the oxidized carbon using a chelation method, (iii) chemical treatment in an acidic medium to remove excess of Co on the carbon surface, (iv) Pt deposition onto the Co/C support, and (v) postheat treatment to form the Pt–Co alloy catalyst. The synthesized Pt–Co/C catalyst showed improved activity and long-term stability in polymer electrolyte membrane …

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