Catalysis and Reaction Engineering Commons^™

Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen

Journal of Electrochemistry

Metal nanoclusters (M NCs) consist of only several to a few hundred of metal atoms and possess core sizes less than 2 nm. Owing to the quantum size effect, the electronic states of M NCs evolve to discrete levels similar to the molecule energy gaps, other than a continuous density of states to produce plasmon characteristic of bulk metal nanoparticles (M NPs). In comparison with the conventional M NPs, M NCs exhibit dramatically unique electronic and optical properties, such as molecule-like energy gaps, strong photoluminescence and high catalytic properties, which make them promising for potential application in numerous fields, such …

Synthesis Of Some N-Oxides Of Pyridylacethylene Amines Based On 2-Methyl-5-Ethynylpyridine, Abduvakhab Ikramov, Odiljon Ziyadullayev, Adkham Khamidjanov, Shavkat Bojariev, Davron Khandamov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to study the reaction of 2-methyl-5-ethynylpyridine N-oxide with some aliphatic and aromatic amines to obtain N-oxides of pyridylacetylenic amines. 2-Methyl-5-ethylpyridine converted to 2-methyl-5-vinylpyridine by dehydrogenation, and 2-methyl-5-ethynylpyridine obtained by bromination and dehydrobromination. 2-methyl-5-ethynylpyridine N-oxide synthesized by oxidation of 2-methyl-5-ethynylpyridine with perhydrol in acetic anhydride. The synthesis of N-oxides of pyridylacetylenic amines by the Mannich reaction carried out. The effect of the solvents: methanol, ethanol and n-dioxane, the catalyst, and the reaction time on the yield of the final product studied. The structure and composition of the synthesized PAA N-oxides were established using IR and …

The Role Of Hydrogen Bonds In Diluted Ethanol Solutions Of Cyclohexane And Dimethylformamide, Dilbar Bozorova, Shukur Gofurov, Mavlonbek Ziyayev, Dildora Mirtojiyeva, Odina Ismanova, Oksana Ismoilova

CHEMISTRY AND CHEMICAL ENGINEERING

The refractometric method and Fourier transform infrared spectroscopy were used to determine the optical features of the concentration characteristics of diluted ethanol solutions of cyclohexane and dimethylformamide. It was found for the first time that at some concentrations the hydrogen bond is stronger than for a pure ethanol solution. The first maximum of the excess refractive index of solutions is formed at a concentration of 0.02 mole fraction of cyclohexane and dimethylformamide, which is in good correlation with IR spectroscopy, indicating the largest number of formed hydrogen bonds.

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis

LSU Doctoral Dissertations

Water scarcity threatens the lives of millions of people worldwide. It is imperative to improve the energy efficiency and affordability of water treatment methods to avoid a looming water-energy crisis. To meet this challenge, I have pursued research on the use of sunlight—our most reliable and abundant source of energy—to drive water treatment through photocatalysis. I explored the literature and found gold-semiconductor materials to hold promise for harvesting sunlight and catalyzing the breakdown of waterborne contaminants. Initially, I designed a novel optical cavity with gold (Au) nanoparticles on a zinc oxide / titania (TiO₂) / aluminum film stack …

Abiotic Sensor For Electrochemical Determination Of Chlorpyrifos In Natural Water Based On The Inhibition Of Silver Nanoparticles Oxidation, Ziad Khalifa, Moustafa Zahran, Magdy Zahran, Magdi Abdelazzem

Chemical Engineering

Chlorpyrifos, organophosphorus pesticide, is a persistent organic pollutant that may cause serious health problems. Herein, a simple, green, and sensitive electrochemical inhibition sensor based on silver nanoparticles (AgNP)-modified glassy carbon (GC) electrode was developed for the determination of chlorpyrifos in natural water for the first time. The chemical reduction technique based on natural reducing and capping agents such as dissolved organic matter (DOM), natural latex (NL) and mucilage was employed for AgNP synthesis. DOM-AgNP, NL-AgNP, and Mucilage-AgNP were immobilized on GC by sticking technique under the same voltammetric and electrolytic conditions. The oxidation behavior of the three modified electrodes was …

Preparation Of Pdcoir Tetrahedron Nanocatalysts And Its Performance Toward Ethanol Oxidation Reaction, Zhi-Yuan Yu, Rui Huang, Jie Liu, Guang Li, Qian-Tong Song, Shi-Gang Sun

Journal of Electrochemistry

As a new energy conversion device, direct ethanol fuel cells (DEFCs) are widely concerned because of their remarkable advantages such as high theoretical energy density and wide fuel sources. However, the rapid development of DEFCs has been severely impeded due to the sluggish kinetic process and toxic intermediates especially in their anodic reactions. Palladium (Pd)-based materials are considered to be excellent anode catalysts for DEFCs, especially under alkaline conditions. And further improving their performance is an important direction to promote the development of DEFCs. Surface structure and composition are the key factors affecting the performance of catalysts which can be …

Research Progress In Electrodeposition Technology Of Titanium-Based Iridium Oxide Electrode, Dan-Dan Wu, Xu Wu

Journal of Electrochemistry

Titanium-based iridium oxide electrode has been widely used in various fields, such as electrocatalytic oxidation, biomedical applications, hydrometallurgical metal recovery, electro-osmotic dewatering, etc. At present, it is mainly prepared by traditional thermal decomposition method, however, which has high cost, cumbersome process, mainly relying on manual labor and cannot be mass-produced yet. It is, therefore, urgently necessary to explore new preparation technologies by focusing on electrodeposition technology, with technological characteristics such as eco-friendly and sustainable development. This article systematically discusses the research progress in iridium oxide electrodeposition preparation technology from the aspects of deposition solution formulation, base material selection and treatment, …

Preparations And Electrocatalytic Ethanol Properties Of Palladium Intercalated Hydrotalcite, Shou-Xun Hu, Liang Li, Jun-Hao Yang, Liu-Qiang Li, Zhi-Hao Jin

Journal of Electrochemistry

High-performance electrocatalysts play a vital role in the commercial application of direct fuel cells. Current anode materials still have such problems as low activity, easy poisoning and high cost. In this study, a new type of nano- palladium (Pd) catalyst was prepared by dipping method using layered double hydroxides (LDHs) as the carrier. X-ray diffractometer, scanning electron microscope (SEM), inductively coupled plasma mass spectrometer (ICP-MS), energy spectrometer, transmission electron microscope (TEM), cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscope were used to analyze the structure and electrocatalytic performance of the catalyst. The results showed that the newly prepared Pd/Mg-Al-LDHs still maintained …

Syntheses Of Na3V2(Po4)2O2F As A Cathode For Sodium Ion Battery Application, Kai Wu

Journal of Electrochemistry

High-temperature solid-state method, hydro-thermal method and solvo-thermal method have been mainly employed to synthesize Na₃V₂(PO₄)₂O₂F (NVPF) cathode materials. However, these methods are energy consuming and complicated, which is not applicable for a large scale industrial production. In this study, a rather low-temperature (70℃) co-precipitation strategy was proposed to synthesize NVPF cathode materials. The as-prepared NVPF cathode materials showed a spherical shape with a diameter of 400 ~ 500 nm, and exhibited a sodium storage of 105.6 mAh·g^-1 and an efficiency of 90.06%. After a simple thermal process, the specific …

Ethinylation Reactions Of Some Aldehydes In The Presence Of Phenylacetylene Using High-Base Catalytic Systems, Abdurakhmanova Saida, Ikramov Abduvaxab, Ziyadullayev Odiljon, Ablakulov Lochin

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research work is the development of synthesis methods of aromatic acetylene alcohols and their various derivatives using different catalytic systems and also, determining their structure, physico-chemical and biological properties. The most effective way of synthesizing AAA is determined using selected complex catalytic systems and also, the range of catalytic activity of used catalysts is created. Acetic aldehyde, benzaldehyde and cyclohexonal, high-base catalytic systems − MOH/ДМСО∙H2O and M2CO3/ДMСO∙H2O with phenylacetylene reaction of enantioselective etynilation were investiged. Efficiency and course of chemical reaction in the process of formation acetylene alcohol affection of temperature, reaction duration, solvents, catalysts and …

Synthesis Of Meta-Altered Arylmaleinamide And Preparation Of Esters In Their Presence, Turaeva Khurshida, Yuldasheva Mukhabbat, Khaydarova Sadokat

CHEMISTRY AND CHEMICAL ENGINEERING

The development of new methods of synthesis using cheaper reagents for the preparation of maleic acid derivatives, the study of chemical properties and the determination of new directions for the practical application of maleic acid derivatives are still relevant. Therefore, the development of this work is an urgent task. The aim of this study was to obtain the synthesis of monomaleinamide compounds under various conditions to obtain arylmaleimide derivatives of maleic acid and to transfer them in a pure state for further reactions. In this study, scientific studies were carried out to find convenient methods for the preparation of monoamide …

Assessment Of Heavy Metal Concentration In Soils Around Geita The Gold Mine, Tanzania, Mariam G. Mgendi, Mkabwa L. K Manoko, W.J.S. Mwegoha, C. Southway C. Southway

Journal of Humanities and Social Sciences

Health issues related to gold mining cannot be underestimated. Gold mining produce acid mine drainage (AMD), which in turn releases heavy metals into the nearby environment, hence causing environmental pollution. Heavy metals are naturally very toxic, thus pose a great health concern especially when their concentration exceeds the recommended permissible limits. In this study, concentrations of five heavy metals—including Pb, Ni, Cr, Cu and Zn—were assessed in the soil around Geita Gold Mine (GGM). A total of 17 sampling sites were established from which the soil samples were collected at 0-15cm and 15-30cm soil depth. The concentration of both total …

New Mechanism Insight For The Hydrogenation Of Co/Co2 Gas Mixtures To Hydrocarbons Over Iron-Based Catalyst, Sandeep Badoga, Michela Martinelli, Muthu Kumaran Gnanamani, Young Koh, Wilson D. Shafer

Center for Applied Energy Research Faculty and Staff Publications

Iron-based catalysts are the most suitable candidates for converting CO₂ or CO₂-rich syngas to hydrocarbons. However, several issues about the mechanism of CO₂ hydrogenation are still unclear. In this work, we investigated the performance of an iron-based catalyst with H₂/CO₂, H₂/CO/N₂ and H₂/CO/¹³CO₂/N₂ gas mixtures at the same process conditions (T = 270°C, P = 175 psi and SV = 3 NL/h/g_cat). The CO₂ hydrogenation rate was much lower than that observed for CO hydrogenation. ¹³CO_{2 …}

Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah

Graduate Theses, Dissertations, and Problem Reports (ETD)

Valorization of Xylan in Agroforestry Waste Streams.

Harrison Appiah

Microwave-assisted deep eutectic solvent and gamma-valerolactone metallic chloride catalyzed conversion of xylan to furfural were investigated using a 2x3 factorial experimental design at two levels of percent microwave power, reaction time, and catalyst concentration. The levels of each factor studied were (20%, 60% microwave power, 2, 4 minutes, and 10, 20mg) respectively. The effect of three metallic chloride catalysts (LiCl, FeCl3.6H20, CuCl2) on the conversion of xylan to furfural was also investigated. The gamma-valerolactone-ferric chloride sent system exhibited the highest mean yield of furfural (56.50%). The next highest furfural yield of …

Biological Conversion Of Carbon Dioxide To Value-Added Chemicals, Owen James Mcgrath

Graduate Theses, Dissertations, and Problem Reports (ETD)

As Carbon Dioxide (CO₂) levels in the atmosphere continue to rise due to human intervention, there is increased urgency to take actions to mitigate the potential ramifications. Many countries have instituted a CO₂ tax and have provided funding to finding potential solutions to our growing CO₂ problem. Further investigating CO₂ capture, sequestration, and utilization is key to combating rising CO₂ levels and methods being investigated have increased substantially in recent years. Converting CO₂ into fuels and value-added chemicals provides a unique opportunity to create materials of value from a substance that is being …

Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research focuses on the synthesis of both shaped and amorphous powder materials, the combination of these materials with dried Powder River Basin (PRB) coal char, and their reactionary properties with methane and carbon dioxide gasses with conventional and microwave (MW) heating. The first goal of this project was to synthesize shaped micro and nano sized particles with ideal dielectric properties for converting electromagnetic energy into heat and proven capabilities of activating methane. These particles were synthesized via solvothermal, hydrothermal, and co-preceptory treatments alone and onto the surface of dried PRB coal char. PRB is a sub-bituminous, low-ranking coal (LRC) …

Improving Performance And Durability Of Intermediate Temperature Proton‐Conducting Solid Oxide Electrolysis Cells Via Materials Design And Catalyst Surface Engineering, Hanchen Tian

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solid oxide steam electrolysis cell, a promising electrical-chemical conversion device for the next generation efficient hydrogen production and energy storage, has been actively studied because of their high energy conversion efficiencies and prospective applications as electrochemical reactors. After decades of research on protonic ceramic materials, remarkable advances have been made in the protonic ceramic electrochemical cells (PCECs) air electrode and electrolyte. However, the existing air electrodes are far from satisfying the requirements of practical applications, a series of issues, including the lack of active and durable electrodes, greatly limit the commercialization. To date, the systematic development of triple conducting catalysts …

Simultaneous Activation Of Stable Molecules- Methane And Nitrogen- Using Microwave Reactor With And Without Plasma- To Produce Ethylene And Ammonia, Sarojini Tiwari

Graduate Theses, Dissertations, and Problem Reports (ETD)

The discovery of stranded natural gas around the world has made shale gas cheaper and widely accessible. This has driven the relevant research towards the direct utilization of Methane (CH4), a major component of natural gas. CH4 is a highly stable molecule, hence its activation and consequent formation of value-added chemicals in a direct and efficient manner is a relevant problem of the 21st century. All the commercial processes convert natural gas to chemicals indirectly, via the formation of syngas followed by several reactions. The conventional systems are energy intensive and one of the major contributors to green-house gas emissions. …

Microwave-Assisted Natural Gas Conversion To Value-Added Chemicals, Xinwei Bai

Graduate Theses, Dissertations, and Problem Reports (ETD)

Stranded gas is a raw gas mixture of volatile hydrocarbons where the main composition is methane. The producers flare the stranded gas at the site because the cost of collecting and transporting the gas is higher than the value of the gas itself. To reduce the waste of this natural resource, it is worthwhile to utilize the on-site stranded natural gas as feedstock to produce value-added chemicals without emitting greenhouse gas. Direct natural gas conversion process is more desirable because of lower capital investment. Methane and ethane, the two major components of natural gas, are very stable molecules that usually …

Effects Of Microporous Structure On The Enzymatic Conversion Of Biomass Using A Multiscale Model, Saketh Merugu

Dissertations, Master's Theses and Master's Reports

The generation of biofuels from lignocellulosic biomass involves innovative process technology that is being investigated worldwide. Enzymatic hydrolysis is a major step in the contemporary process of the generation of biofuels. Guided by pore size distribution measured using NMR cryoporometry, we developed pore-enzyme diffusion and adsorption models at the particle level coupled with a kinetic model for cellulose, cellobiose, and glucose production at flask level. By simulating these models in MATLAB, COMSOL, and Polymath software packages, we investigate the effects of various biomass particle-related parameters (particle dimensions, porosity, enzyme accessibility) on the characteristic time of enzyme diffusion and adsorption and …