Catalysis and Reaction Engineering Commons^™

Ternary Alloy Electrocatalysts For Oxygen Reduction Reaction, Jin Luo, Lefu Yang, Binghui Chen, Chuanjian Zhong

Journal of Electrochemistry

Proton exchange membrane fuel cell represents an important electrochemical energy conversion device with many attractive features in terms of efficiency of energy conversion and minimization of environmental pollution. However, the large overpotential for oxygen reduction reaction at the cathode and the low activity, poor durability and high cost of platinum-based catalysts in the fuel cells constitute a focal point of major barriers to the commercialization of fuel cells. The development of nanostructured catalysts shows promises to addresses some of the challenging problems. The ability to engineer the composition and nanostructure of nanoalloy catalysts is important for developing active, robust and …

Electrocatalytic Activity Of Palladium Nanocatalysts Supported On Carbon Nanoparticles In Formic Acid Oxidation, Jie Huang, Zhiyou Zhou, Yang Song, Xiongwu Kang, Ke Liu, Wancheng Zhou, Shaowei Chen

Journal of Electrochemistry

Palladium nanostructures were deposited onto carbon nanoparticle surface by a chemical reduction method. Transmission electron microscopic studies showed that whereas the resulting metal-carbon (Pd-CNP) nanocomposites exhibited a diameter of 20 to 30 nm, the metal components actually showed a cauliflower-like surface morphology that consisted of numerous smaller Pd nanoparticles (3 to 8 nm). Electrochemical studies showed that the effective surface area of the Pd-CNP nanoparticles was about 40% less than that of Pd black, possibly because the Pd nanoparticles were coated with a layer of carbon nanoparticles; yet, the Pd-CNP nanocomposites exhibited marked enhancement of the electrocatalytic activity in formic …

Electrocatalytic Oxidation Of Formic Acid On Pd/Ni Heterostructured Catalyst, Mingjun Ren, Liangliang Zou, Ju Chen, Ting Yuan, Qinghong Huang, Haifeng Zhang, Hui Yang, Songlin Feng

Journal of Electrochemistry

A Pd/Ni bimetallic nanostructured electrocatalyst was fabricated via a two-step reduction route. Owing to an epitaxial growth of Pd atoms on the surface of Ni nanoparticles, heterostructured Pd/Ni nanocomposites were formed and verified by high resolution transmission electron microscopy combined with energy-dispersion X-ray spectroscopy. X-ray diffraction confirmed that the as-prepared Pd/Ni nanocomposites possessed a single face-centered-cubic (fcc) Pd structure, probably due to a weaker diffraction intensity of metallic Ni and/or overlapping by that of Pd. The intrinsic catalytic activity on the Pd/Ni is higher than that on the Pd. Moreover, the durability of formic acid oxidation on the Pd/Ni was …

Refractive Index Chemical Sensing With Noble Metal Nanoparticles, Phillip Blake

Graduate Theses and Dissertations

Chemical sensing is a key component in modern society, especially in engineering applications. Because of their widespread impact, improvements to chemical sensors are a significant area of research. One class of sensors, plasmonic sensors, is being heavily researched because of their ability to detect low levels of analyte in near real time without destroying the analyte. This work studies a new class of plasmonic sensor that utilizes diffractive coupling to improve sensor performance. Specifically, this work outlines the first study of diffractive coupling sensors with typical nanoparticle shapes. Sensitivity of this new class of sensor is directly compared to typical …

The Oxidation Of Hydrogen Peroxide On Nanostructured Rhodium Microelectrodes, N. Bartlett Philip, F. Esterle Thomas

Journal of Electrochemistry

Mesoporous Rh films were deposited onto platinum microelectrodes from the H₁ lyotropic liquid crystalline phase of C₁₂EO₈ (octaethyleneglycol monododecyl ether). The electrodes show well defined voltammetry for the oxidation and the reduction of hydrogen peroxide at low concentrations (<10 mmol•L-1) with excellent stability for operation at neutral pH. Based on the hysteresis in the current and the potential dependence the oxidation of hydrogen peroxide occurs through a CEE mechanism involving Rh(OH)₃ on the mesoporous Rh electrode surface. At higher hydrogen peroxide concentrations the current reaches a plateau that is due to either saturation of the binding sites for hydrogen peroxide or limitation of the reaction due to acidification of the solution within the pores. For the thin films (below 200 nm) the hydrogen peroxide calibration curves we …

Electrochemical Synthesis Of Silver-Tetracyanoquinodimethane Nanorods At Agar Supported Water/1,2-Dichloroethane Interface, Li Huang, Yixian Wang, Michael V. Mirkin, Bin Ren, Dongping Zhan

Journal of Electrochemistry

Silver-tetracyanoquinodimethane (AgTCNQ) is an important charge transfer salt due to its high conductivity and other electronic properties. In this communication, we report the synthesis of AgTCNQ at the liquid/liquid interface. Agar was used as a gelling agent to support water/1,2-dichloroethane (DCE) interface. Silver ions were transferred from the hydrogel into DCE phase, where they combined with TCNQ^- to form AgTCNQ nanorods. The developed method can provide a new route for synthesis of functional materials based on the electrochemistry at the liquid/liquid interface.

Optimization Of Biodiesel Production Plants, Nghi T. Nguyen

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

A conventional biodiesel plant utilizing two distillation columns to purify unreacted reactants and products is considered in this study. Thermodynamic analyses are used to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a biodiesel production plant. After the retrofits, the overall exergy loss for the two columns has decreased from 2430.87 kW to 1674.12 kW.

A reactive distillation is developed for esterification of lauric acid with methanol using equilibrium and nonequilibrium models. Equilibrium modeling dominated during last few decades due to their straightforward mathematical modeling. In reality, separation depends on …

Characterization Of Heterogeneous Reaction Systems By Thermal Analysis And Mathematical Modeling, Shreya Adhikari, Chuck Tillie

Undergraduate Research Posters 2012

It is anticipated that this research will lead to scale-up parameters that can be used to model a laboratory-scale deposition furnace, and guide further experimentation to advance technologies for protective and conversion coatings.

Synthesis And Electrochemical Characterization Of Li3V2(Po4)3/C Cathode Material By Ball-Milling Assisted Microwave Method, Zhi-Yuan Tang, Wen-Feng Mao, Ji Yan, Wei Yuan, Xin-He Zhang

Journal of Electrochemistry

The cathode materials of Li₃V₂(PO₄)₃/C were successfully synthesized by ball-milling assisted microwave method and the microwave irradiation time was also optimized. It is found that the Li₃V₂(PO₄)₃/C material obtained at a microwave power of 640 W for 18 min showed the best electrochemical performance with the initial reversible capacity of 101.3 mAh·g^-1 and the remained 100.8 mAh·g^-1 at 5C rate after 300 cycles. This excellent electrochemical capability may be resulted from good crystallinity, smaller and uniform particle size of the material, showing …

Synthesis And Electrochemical Properties Of High-Capacity Cathode Material 0.08lico0.75Al0.25O2-0.92linio2, Ru-Ying Wang, Tian Qiu, Chong Mao, Wen-Sheng Yang

Journal of Electrochemistry

CoAl-LDH or Co(OH)₂ coated spherical Ni(OH)₂ precursors were obtained via a co-precipitation method at a constant pH. The mixtures of the precursors and LiOH·H₂O were annealed at high temperature in O₂ atmosphere, and then the cathode materials of 0.08LiCo_0.75Al_0.25O₂-0.92LiNiO₂, 0.08LiCoO₂-0.92LiNiO₂ and LiNiO₂ were synthesized. Effects of the coating layer were also studied. The results showed that the 0.08LiCo_0.75Al_0.25O₂-0.92LiNiO₂ material possessed the best rate and cycle life performance. The discharging capacities at 0.1C, 0.5C and 3C were …

Electrochemical Performances Of Layered Polypyrrole/Chemically Reduced Graphene Oxide Nanocomposites As Supercapacitor Electrodes, Si-Zhe Xu, Xue-Jiao Zhou, Kun Wu, Yong-Qiang Yang, Hai-Xia Wu

Journal of Electrochemistry

Nanocomposites of polypyrrole (Ppy) and chemically reduced graphene oxide (CRGO), Ppy/CRGO, have been fabricated through in-situ polymerization of pyrrole on graphene oxide (GO) sheets. The as-synthesized Ppy/CRGO composites were characterized complementarily using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FT-IR). By controlling the initial ratio of the GO to pyrrole, the layered composites could be obtained and their thickness could be tuned properly. The Ppy/CRGO electrodes were prepared using a mechanical compressing technique and their electrical conductivity and electrochemical properties were characterized systematically. We demonstrated that as electrodes for supercapacitor, the Ppy/CRGO composites with Ppy …

Electrocatalytic Activities Of Mb/Aunps/Mwnts/Gc Electrode For Hydrogen Peroxide Reduction, Zheng-Juan Huang, Hua-Ping Peng, Dai-Jun Cha, Ai-Lin Liu, Wei Chen, Xin-Hua Lin, Yong-Ji You

Journal of Electrochemistry

A novel matrix, multiwalled carbon nanotubes supported Au nanoparticles composite nanomaterial (AuNPs/MWNTs), for immobilization of protein and biosensing was designed using a simple and effective one-step in situ synthesis route. Using myoglobin (Mb) as a model, the direct electrochemistry of the immobilized proteins on the AuNPs/MWNTs composite was studied. The results showed that the AuNPs/MWNTs composite can maintain the bioactivity and facilitate the direct electrochemistry of Mb in the Mb/AuNPs/MWNTs/GC electrode. Based on the direct electron transfer of the immobilized Mb, the protein electrode exhibited excellent electrocatalytic activity to the reduction of H₂O₂ with a linear range …

En Route Towards Α-Benzotriazoyl Nitroso Derivatives, Jean-Christophe M. Monbaliu, Lucas K. Beagle, Judit K. Beagle, Matthias Zeller, Christian V. Stevens, Alan R. Katritzky

Chemistry Faculty Publications

A new class of geminally-substituted nitroso compounds, i.e., α-benzotriazoyl nitroso derivatives, is presented. These compounds display a rather different behavior than other related nitroso compounds bearing a geminal electron-withdrawing group. An unexpected and spontaneous oxidation to the nitro analog is observed in solution.

Optimization Of A Dynamic Hot Water Pretreatment Of Switchgrass Using Catalysis By Carbonation To Maximize Carbochemical Yields, Rohit Tanaji Dhamdere

Graduate Theses and Dissertations

A bio-refinery is a facility that converts renewable bio-resources into value-added chemicals and products. In this context of a bio-refinery, the production of the carbochemicals such as HMF, furfural and organic acids illustrate that multiple products can be produced from a renewable source such as lignocellulosic biomass (switchgrass). Traditionally, carbochemicals such as furfural and HMF are produced using inorganic acids such as H2SO4, HCL, and H3PO4. The use of such acids requires the application of high cost materials of construction such as Hastelloy-C, titanium etc.

The objective of this study is to develop a semi-continuous process for the conversion of …

Solid Oxide Fuel Cells With Both High Voltage And Power Output By Utilizing Beneficial Interfacial Reaction, Chao Su, Zongping Shao, Ye Lin, Yuzhou Wu, Huanting Wang

Faculty Publications

An intriguing cell concept by applying proton-conducting oxide as the ionic conducting phase in the anode and taking advantage of beneficial interfacial reaction between anode and electrolyte is proposed to successfully achieve both high open circuit voltage (OCV) and power output for SOFCs with thin-film samarium doped ceria (SDC) electrolyte at temperatures higher than 600 °C. The fuel cells were fabricated by conventional route without introducing an additional processing step. A very thin and dense interfacial layer (2–3 μm) with compositional gradient was created by in situ reaction between anode and electrolyte although the anode substrate had high surface roughness …

An Overview Of Electrode Materials In Microbial Fuel Cells, Su-Qin Ci, Na Wu, Zhen-Hai Wen, Jing-Hong Li

Journal of Electrochemistry

Microbial fuel cells (MFCs) are devices that can directly convert organic chemical energy into electrical energy with microbial as catalysts. MFCs are a promising bio-electrochemical system with the potential to degrade organic sewage and produce electricity. This article supplies a critical and comprehensive review for the electrode materials concerning about anode and cathode in MFCs, including the fabrications, functional modifications and surface constructions of electrode materials, as well as their applications in MFCs. Additionally, the existing problems of electrode materials in current MFCs have been demonstrated in order to provide the guideline for exploring the next-generation electrode materials for MFCs.

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 …

The Electrocatalytic Performance Of Pd Catalysts Supported On Pvp Modified Mwcnts For Formic Acid Oxidation, Jing Zhang, Xiao Zhao, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

In this paper the MWCNTs were modified by Poly (N-vinyl-2-pyrrolidone) (PVP) to support Pd nanoparticles, which were used as the catalyst for formic acid electrooxidation. And the performance of Pd/PVP-MWCNTs catalysts was studied by electrochemical measurements. The observations from Fourier transforms infrared spectrometer (FTIR) and transmission electron microscopy (TEM) illustrated that the Pd nanoparticles with a small size and narrow size distribution were highly dispersed on PVP-MWCNT support. Therefore, the Pd/PVP-MWCNTs catalysts showed excellent catalytic activity for formic acid electrooxidation.

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 …