Catalysis and Reaction Engineering Commons^™

Fabrication Of Mnox/Mwcnts-Gc Nanocatalyst For Oxygen Evolution Reaction, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Amr M. Arafa Eng.

Chemical Engineering

Manganese oxide (MnOx) and multiwalled carbon nanotubes (MWCNTs) are intended to modify the GC electrode for oxygen evolution reaction (OER). Optimization of MnOx loading is carried out and the deposition of 55 cycles was sufficient to obtain the highest activity toward OER. The stability of the catalyst is enhanced by the addition of MWCNTs. As a result, an amount of 22 kWh/Kg of O2 of energy is saved. Several techniques including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy will be combined to track the catalyst activity and to determine its morphology …

Assembling Of Niox/Mwcnts-Gc Anodic Nanocatalyst For Water Electrolysis Applications, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Saher D. Khamis Eng

Chemical Engineering

Glassy carbon (GC) electrode is intended to be modified with nickel oxide (NiOx) and multiwalled carbon nanotubes (MWCNTs) in the anodic reaction of water electrolysis. NiOx deposition time is optimized and a 5 min was enough to attain the maximum activity. A further modification of the catalyst with MWCNTs could greatly enhance its stability during continuous electrolysis. As an outcome, an energy amount of 21.7 kWh/KgO2 is minimized. Several electrochemical and materials characterization setups will be utilized to test the catalyst activity and to know its geometry and structure.

Fabrication Of Cuox-Pd Nanocatalyst Supported On A Glassy Carbon Electrode For Enhanced Formic Acid Electro-Oxidation, Islam M. Al-Akraa Dr., Ahmad M. Mohammad Prof, Mohamed S. El-Deab Prof, Bahgat E. El-Anadouli Prof

Chemical Engineering

Formic acid (FA) electro-oxidation (FAO) was investigated at a binary catalyst composed of palladium nanoparticles (PdNPs) and copper oxide nanowires (CuOxNWs) and assembled onto a glassy carbon (GC) electrode. /e deposition sequence of PdNPs and CuOxNWs was properly adjusted in such a way that could improve the electrocatalytic activity and stability of the electrode toward FAO. Several techniques including cyclic voltammetry, chronoamperometry, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were all combined to report the catalyst’s activity and to evaluate its morphology, composition, and structure. /e highest catalytic activity and stability were obtained at the CuOx/Pd/GC …

The Role Of Microenvironment Reagent Solubility On Reaction Kinetics Of 4-Nitrophenol Reduction, Michael P. Zeevi, Andrew Harrison, Christina Tang

Undergraduate Research Posters

The Role of Microenvironment Reagent Solubility on Reaction Kinetics of 4-Nitrophenol Reduction

Michael Zeevi¹ with Andrew Harrison¹ and Christina Tang, PhD¹

¹Department of Chemical and Life Science Engineering, VCU School of Engineering

Introduction: Nanoparticles are of increasing interest due to their high surface area to volume ratio, as well as that they enable fine-tuning of the reaction microenvironment. Through flash nanoprecipitation, core-shell polymer nanoreactors were formed by directed self-assembly. Using the reduction of 4-nitrophenol as a model reduction reaction, we investigated the effect of reagent solubility in the nanoreactor microenvironment’s on nanoreactor kinetics.

Methods: The standard …

Graphene As A Solid-State Ligand For Palladium Catalyzed Cross-Coupling Reactions, Yuan Yang

Theses and Dissertations

Palladium-catalyzed carbon-carbon cross-coupling reactions have emerged a broadly useful, selective and widely applicable method to synthesize pharmaceutical active ingredients. As currently practiced in the pharmaceutical industry, homogeneous Pd catalysts are typically used in cross-coupling reactions. The rational development of heterogeneous catalysts for cross-coupling reactions is critical for overcoming the major drawbacks of homogeneous catalysis including difficulties in the separation, purification, and quality control process in drug production. In order to apply heterogeneous catalysis to flow reactors that may overcome this limitation, the catalyst must be strongly bound to a support, highly stable with respect to leaching, and highly active. While …

Electroactivities Of Pd/Fe3O4-C Catalysts For Electro-Oxidation Of Methanol, Ethanol And Propanol, Tao Zou, Qing-Feng Yi, Yuan-Yuan Zhang, Xiao-Ping Liu, Guo-Rong Xu, Hui-Dong Nie, Xiu-Lin Zhou

Journal of Electrochemistry

Development of palladium (Pd) catalysts with high electroactivity for alcohol oxidation is significant for alcohol fuel cells. In this work, Pd nanoparticles were formed by sodium borohydride (NaBH₄) reduction method and subsequently deposited on the surface of carbon supported ferriferrous oxide (Fe₃O₄/C) composites to obtain the Pd/Fe₃O₄-C catalysts with different Fe₃O₄ loadings. Their transmission electron microscopic (TEM) images show that the Pd nanoparticles were uniformly dispersed on the Fe₃O₄/C. Electroactivities of the prepared Pd/Fe₃O₄-C catalysts toward oxidations of C1-C3 …

Kinetics And Mechanism Toward Electrochemical Reductions Of Sodium Bromide And Methanol Over Iron Electrodes, Qun Liao, Shu-Feng Zhang, Wen-Hua Leng

Journal of Electrochemistry

It is of technological value and scientific interest to the electro-synthesis of ferrocene, conversion of carbon dioxide (CO₂) and organic electro-synthesis in non-aqueous solutions by investigating the kinetics and mechanism toward electrochemical reductions of sodium bromide (NaBr) and methanol over iron electrodes. However, few reports in the related researches are available. In this article, the kinetics and mechanism toward electrochemical reductions of NaBr and methanol over iron electrodes were examined in detail by carrying out the polarization curve and electrochemical impedance spectroscopic measurements. The results showed that methanol was the reactant, while Na⁺ ions were functioned only …

Cobalt-Based Nitrogen-Doped Carbon Non-Noble Metal Catalysts For Oxygen Reduction Reaction, Meng-Xiu Jiang, Jing Zhang, Yue-Hua Li, Rong Zhang

Journal of Electrochemistry

Transition metal-nitrogen co-doped carbon catalysts have attracted significant attention because of their reasonable activity and remarkable selectivity toward oxygen reduction reaction (ORR) as cathodic reaction in fuel cells. However, the role of transition metal in the active sites of the catalysts still is uncertain. In this work, the Co_x-N_y/C-T catalysts were prepared with BP2000 as a carbon source, urea (Ur) as a nitrogen source and Co(OAc)₂•4H₂O as a metal precursor by a simple chemical method. Meanwhile, in order to optimize the ORR activity, the catalysts were synthesized with different amounts of Co …

Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

This paper describes a simple CO-assisted reduction approach for the controllable synthesis of ultrathin Pd nanowires along the one-dimensional (1D) direction. Ultrathin Pt films from one to several atomic layers were successfully decorated onto ultrathin Pd nanowires by utilizing Cu UPD deposition, and followed by in-situ redox replacement reaction of UPD Cu by Pt. The core–shell structure and composition of the Pd@Pt ultrathin nanowires have been verified using transmission electron microscopy and energy dispersive X-ray spectrometry. The core–shell Pd@Pt ultrathin nanowires exhibited comparative electrocatalytic activity and improved durability for the oxygen reduction reaction in comparison with commercial Pt black. The …

Effect Of Fe2+/Fe3+Interconvertion On Reduction Behavior Of Fe3+ In Acidic Electrolytes, Jian-Xin Qin, Feng Lin, Wen-Ping Liu, Chao Chen, Meng-De Ren

Journal of Electrochemistry

The influences of ferrous/ferric (Fe²⁺/Fe³⁺) interconvertion on electrochemical reduction and electrode reaction of Fe³⁺ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl^-) and sulfate ion (SO₄^2-). It was shown that the reduction process of Fe³⁺/Fe²⁺ would take place in two independent stages: (1) the reduction of Fe³⁺ to Fe²⁺ at E=0.35V and (2) the co-precipitation of Fe²⁺ by forming Fe(OH)₂ (E≤-0.3 V) instead of Fe. The major effect of Fe^{2+ …}

An Application Of M-Matrices To Preserve Bounded Positive Solutions To The Evolution Equations Of Biofilm Models, Richard S. Landry Jr.

LSU New Orleans Theses and Dissertations

In this work, we design a linear, two step implicit finite difference method to approximate the solutions of a biological system that describes the interaction between a microbial colony and a surrounding substrate. Three separate models are analyzed, all of which can be described as systems of partial differential equations (PDE)s with nonlinear diffusion and reaction, where the biological colony grows and decays based on the substrate bioavailability. The systems under investigation are all complex models describing the dynamics of biological films. In view of the difficulties to calculate analytical solutions of the models, we design here a numerical technique …

Synergistic Interactions Of H2 And N2 With Molten Gallium In The Presence Of Plasma, Maria L. Carreon, Daniel F. Jaramillo-Cabanzo, Indira Chaudhuri, Madhu Menon, Mahendra K. Sunkara

Physics and Astronomy Faculty Publications

The present study examines the interaction of hydrogen and nitrogen plasmas with gallium in an effort to gain insights into the mechanisms behind the synergetic effect of plasma and a catalytic metal. Absorption/desorption experiments were performed, accompanied by theoretical-computational calculations. Experiments were carried out in a plasma-enhanced, Ga-packed, batch reactor and entailed monitoring the change in pressure at different temperatures. The results indicated a rapid adsorption/dissolution of the gas into the molten metal when gallium was exposed to plasma, even at a low temperature of 100 °C. The experimental observations, when hydrogen was used, indicate that gallium acts as a …

Microbial Desalination Cells With Efficient Platinum Group Metal-Free Cathode Catalysts, Morteza Rezaei Talarposhti

Chemical and Biological Engineering ETDs

Iron-nitrogen-carbon based catalyst was used at the cathode of a microbial desalination cell (MDC) and compared with platinum (Pt) and activated carbon (AC) cathode. Fe-N-C catalyst was prepared using nicarbazin (NCB) as organic precursor by sacrificial support method (SSM). Rotating ring disk electrode (RRDE) experiments shows that Fe-NCB had higher electrocatalytic activity compared to AC and Pt. The utilization of Fe-NCB into the cathode improved substantially the performance output with initial maximum power density of 49±2 μWcm^-2 in contrast to Pt and AC catalysts which have shown lower values of 34±1 μWcm^-2 and 23.5±1.5 μWcm^-2, respectively. …

What Happens To Nox Emissions Of Vw Diesel Cars When Water/Methanol Injection Is Used?, Andrew Croxell

ASA Multidisciplinary Research Symposium

Volkswagen has come under fire for their "Clean Diesel" automobiles that were found to emit too much NOx (Oxides of Nitrogen) when driven on the street. Since NOx is created by high temperature combustion events, the addition of a water/methanol injection system was tested on a VW diesel vehicle to identify if it could cool combustion temperatures and thus reduce NOx to an acceptable specification.

Ga And In Modified Ceria As A Support For Cobalt Fischer-Tropsch Synthesis, Muthu Kumaran Gnanamani, Gary Jacobs, Wilson D. Shafer, Michela Martinelli, Donald C. Cronauer, A. Jeremy Kropf, Christopher L. Marshall, Burtron H. Davis

Center for Applied Energy Research Faculty and Staff Publications

Ceria modified by the addition of gallium or indium (20 mol%) was used as a support for cobalt Fischer-Tropsch synthesis. The addition of gallium to ceria improved the CO conversion for cobalt, whereas indium tended to decrease it. A similar trend was observed with the Ag-promoted cobalt/ceria catalysts that were doped with Ga or In. For Ag promoted catalysts, doping with Ga or In decreased methane and increased the product selectivities of olefins and alcohols. The sum of olefins and alcohols in terms of product selectivity for the Ag-promoted catalysts decreased in the following order: Ag-Co/Ce-Ga > Ag-Co/Ce-In > Ag-Co/Ce. The H2-TPR-XANES …

Thermo-Stability And Active Site Structure Of Fe/N/C Electrocatalyst For Oxygen Reduction Reaction, Chi Chen, Yu-Jiao Lai, Zhi-You Zhou, Xin-Sheng Zhang, Shi-Gang Sun

Journal of Electrochemistry

The development of Fe/N/C electrocatalyst for oxygen reduction reaction (ORR) is vital for the large-scale applications of proton exchange membrane fuel cells. Understanding the active site structure will contribute to the rational design of highly active catalysts. In this study, the as-prepared Fe/N/C catalyst based on poly-m-phenylenediamine (PmPDA-FeN_x/C) catalyst with the high ORR activity was subjected to the high-temperature heat treatment again at 1000 ~1500 ^oC. The degradation of in the ORR activity of PmPDA-FeN_x/C by with various heat treatments was correlated to the change of elemental compositions, chemical states and textural properties. As the …

A New Type Carbon Composited Molybdenum Doped Vanadium Oxide Nanowires As A Cathode Material For Sodium Ion Batteries, Guang-Rui Zhang, Li-Qiang Hu, Bao-Zhu Zhang

Journal of Electrochemistry

In recent years, the development of lithium ion batteries (LIBs) has been limited due to the insufficient lithium resource and increasing cost. As a promising candidate, sodium ion batteries (SIBs) with the similar electrochemical mechanism and lower cost than LIBs are developing rapidly. However, as a result of the larger radius of Na⁺ compared with Li⁺, the crystalline structures of the most electrode materials are damaged severely during the intercalation of Na⁺, which limits the electrochemical properties of SIBs. Thus, developing new types of electrode materials for SIBs is particularly important. Among the cathode materials, …

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

Biosystems and Agricultural Engineering Faculty Publications

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

Modeling The Aqueous-Phase Copper Ion-Exchange Behavior Onto Ssz-13 Zeolites, Brian N. Bayer, Rajamani Gounder, Trevor M. Lardinois

The Summer Undergraduate Research Fellowship (SURF) Symposium

Copper-exchanged zeolites are utilized as catalysts for the selective catalytic reduction of nitrogen oxides, which are atmospheric pollutants found in diesel engine exhaust. The total amount of copper ions and the types of copper species (Cu(II) or Cu(II)OH) exchanged onto a zeolite can be varied. Copper is exchanged onto SSZ-13 (an aluminosilicate zeolite with the chabazite topology) during a process known as aqueous ion exchange, where the zeolite is mixed in a copper-containing solution. The distribution of copper on SSZ-13 is influenced by exchange conditions, including the molarity, temperature, and pH of the copper solution. The effect of exchange conditions …

Enhancements In Mass Transfer For Carbon Capture Solvents Part I: Homogeneous Catalyst, Leland R. Widger, Moushumi Sarma, Jonathan J. Bryant, David S. Mannel, Jesse G. Thompson, Cameron A. Lippert, Kunlei Liu

Center for Applied Energy Research Faculty and Staff Publications

The novel small molecule carbonic anhydrase (CA) mimic [Co^III(Salphen-COO⁻)Cl]HNEt₃ (1), was synthesized as an additive for increasing CO₂ absorption rates in amine-based post-combustion carbon capture processes (CCS), and its efficacy was verified. 1 was designed for use in a kinetically slow but thermally stable blended solvent, containing the primary amines 1-amino-2-propanol (A2P) and 2-amino-2-methyl-1-propanol (AMP). Together, the A2P/AMP solvent and 1 reduce the overall energy penalty associated with CO₂ capture from coal-derived flue gas, relative to the baseline solvent MEA. 1 is also effective at increasing absorption kinetics of kinetically fast solvents, such …