Physical Sciences and Mathematics Commons^™

Metal Free Bond Activation By Carboranyl Phosphines, Gayathri B. Gange

Theses and Dissertations

In the past few decades, main group-based catalysts have attracted increasing attention as an alternative approach to overcome the most prevailing issues of transition metal catalysts such as high cost, toxicity, and low abundance. Among these main groupbased catalysts, Phosphine based compounds have shown a variety of bond activations due to the strong nucleophilicity from their congener species. To the contrary, unique electron deficient boron-based clusters have the tendency to accept two electrons reversibly due to their electron deficiency. In this study, we have synchronized the electron donor ability of the phosphine with the electron acceptor ability of the ortho …

Biomimetic Synthesis Of Palladium Nanoparticles For Catalytic Application, Emily A. Groover

Electronic Theses and Dissertations

The synthesis of palladium nanoparticles (Pd NPs) using materials-directed peptides is a novel, nontoxic approach which exerts a high level of control over the particle size and shape. This biomimetic technique is environmentally benign, featuring nonhazardous ligands and ambient conditions. Nanoparticles are extremely reactive catalysts, boasting a large surface-to-volume ratio when compared to their bulk counterparts. The rational design of these nanoparticles using peptides has been very successful in aqueous environments, but no research has been done to apply it in organic systems. As such, the biomimetic synthesis of Pd NPs in an organic system is here investigated, with ethanol …

Investigation Of Environmental-Friendly, Membraneless Hydrogen Peroxide Fuel Cells, Bao Nguyen

Dissertations and Theses

Human-induced climate change is one of the biggest threats to humanity in the 21^st century. This is caused by the increase in greenhouse gas concentrations in the Earth's atmosphere. The burning of fossil fuels is the primary cause of climate change. This problem can be addressed by replacing fossil fuels with fuel sources that have clean by-products and are cost-effective. For the last few decades, hydrogen (H₂) has been extensively studied as an alternative to carbon-based fossil fuels. Currently, H₂ still has many shortcomings for commercial applications. The photocatalytic production of H₂ still suffers from …

Nsf Career Award Supports Schwartz's Research On The Chemical Process For Making Rubber Component, Marcus Wolf

General University of Maine Publications

advance his ongoing dissection of the Lebedev process. The well-known, multi-step chemical reaction is used to make butadiene from biomass-derived ethanol. However, little research has been conducted on the Lebedev process at the molecular level. Understanding the intricacies of this process will help researchers create new catalysts necessary for the chemical reactions to make goods from both petroleum and biomass, that would increase butadiene yield.

Advances In Polymer Based Friedlander Quinoline Synthesis, Rajendra Patil, Jagdish Chavan, Shivnath Patel, Anil Beldar

Turkish Journal of Chemistry

Nitrogen containing heterocyclic compounds has acquired their remarkable and distinct place in the wide area of organic synthesis due to the broad range of applications. Among them, quinoline motifs have attracted researchers in the synthetic chemistry because of its presence in the large number of pharmacologically active compounds. Different methods for synthesis of quinoline derivatives are reported, among them the Friedlander synthesis have provided comparatively more efficient approach. Many of the reported conventional Friedlander methodologies have some problems such as difficult product isolation procedures, poor yields and use of expensive catalysts, etc. Recently, polymer or solid supported synthetic approaches have …

Composite Zeolite Beta Catalysts For Catalytic Hydrocracking Of Plastic Waste To Liquid Fuels, Dureem Munir, Hassaan Amer, Rabya Aslam, Mohamed Bououdina, Muhammad Rashid Usman

Publications and Scholarship

Abstract The conversion of model waste plastic mixture into high-value liquid product was studied in the presence of hydrogen and composites of zeolite beta catalysts. For the sake of comparison, the conversion of actual waste plastic mixture and high-density polyethylene was also carried out. The composite zeolite beta catalysts were synthesized using a range of silica-to-alumina ratios, alkali concentrations, and hydrothermal treatment times. SEM, EDX, XRD, N2-BET, FTIR, and py-FTIR were used for the characterization of the catalysts. The catalytic experiments were conducted in a 500 ml stirred batch reactor at 20 bar initial cold H2 pressure and the temperature …

Synthesis Of Ether Alcohols With Varying Catalysts, Hannah Grady, Frida Li, Jeffrey A. Hansen

Annual Student Research Poster Session

No abstract provided.

Beyond Density Functional Theory: The Multiconfigurational Approach To Model Heterogeneous Catalysis, Samuel J. Stoneburner, Carlo Alberto Gaggioli, Christopher J. Cramer, Laura Gagliardi

Educator Scholarship

Catalytic processes are crucially important for many practical chemical applications. Heterogeneous catalysts are especially appealing because of their high stability and the relative ease with which they may be recovered and reused. Computational modeling can play an important role in the design of more catalytically active materials through the identification of reaction mechanisms and the opportunity to assess hypothetical catalysts in silico prior to experimental verification. Kohn-Sham density functional theory (KS-DFT) is the most used method in computational catalysis because it is affordable and it gives results of reasonable accuracy in many instances. Furthermore, it can be employed in a …

Catalytic Hydrogenation Of Furfural And Furfuryl Alcohol To Fuel Additives And Value-Added Chemicals, Obaid Aldosari, Hamed Alshammari, Mosaed Alhumaimess, Ibrahim Wawata

Turkish Journal of Chemistry

The selective hydrogenation of furfural and furfuryl alcohol at different temperatures has been studied using several catalysts. The effect of various reaction conditions (pressure, catalyst amount, and solvent) was studied. We have shown that Pd/TiO$_{2}$ catalysts can be very effective for the synthesis of 2-methylfuran at room temperature. Using octane as a solvent, the solvent effectiveness was investigated and showed actively high selectivity towards 2-methylfuran and furfuryl alcohol, but there were many byproducts that were still noticed. Although adding Ru to the Pd/TiO$_{2}$ catalyst contributed to reducing the catalytic activity, this addition improved the selectivity to 2-methylfuran and furfuryl alcohol …

Anchoring Cu 1 Species Over Nanodiamond-Graphene For Semi-Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mi Peng, Zhimin Jia, Jinglin Xie, Dequan Xiao, Xiaodong Wen, Ning Wang, Zheng Jiang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamondgraphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding …

Photoelectrochemical Studies On Non-Noble Metal Based Catalysts Towards Tandem Solar Water Splitting, Arun Siddarth Sridhar

Dissertations

Photoelectrochemical (PEC) water splitting makes direct use of solar energy incident on semiconductor photoelectrodes, and it is a convenient, economic option to produce high purity hydrogen at low temperatures. The use of multiple light absorbers can increase overall solar energy utilization and provide a solution to the trade-off between overall band gap and band edge positioning of photoelectrodes specific to solar water oxidation and water reduction. The study of non-noble metal based catalysts for hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) are essential for economic practical commercialization of photo-electrolyzers. This dissertation focuses on the use of a variety …

Applications Of Electrospinning In Lithium-Air Batteries, Yue Fu, Jin Wang, Hai-Yang Yu, Jing-Hua Tian, Rui-Zhi Yang

Journal of Electrochemistry

Lithium-air batteries have received increasing attention as the “ultimate batteries” due to their extremely high theoretical capacity and environment friendly. However, there are still many obstacles hindering the wide applications of the lithium-air batteries owing to the limitations of large charge-discharge over-potentials, poor Columbic efficiency and cycling performance. Exploring of high-efficiency, low-cost and eco-friendly catalysts is one of the vital issues for lithium-air batteries. Meanwhile, electrospinning techniques have been under substantial developments due to its simple fabrication process, high efficiency and production. This paper reviews the recent progresses in fabrications of various novel catalysts for lithium-air batteries with electrospinning techniques, …

Development Of Bifunctional Thiourea Catalysts For Effective Direct Amidation Reactions, Alex Guzman

Summer Research

This research synthesized and analyzed novel catalysts that can effectively form amides. An amide is a chemical group commonly found in many pharmaceuticals and biochemicals, such as proteins. In fact, about 30% of pharmaceuticals contain an amide, and the formation of amides leads to corrosive and toxic by-products which are especially problematic on the large industrial scale. Green Chemistry has proven to be a critical tool in providing innovative solutions by making the industrial production of chemicals more sustainable and safe. The pharmaceutical industry has some of the most inefficient reactions in the chemical industry mainly due to the complexity …

Raman Spectroscopy Of Oxygen Evolution Catalysts And Psii Manganese Model Compounds, Sergei Shmakov, Daniel A. Hartzler, Alireza Karbakhsh Ravari, Yulia Pushkar

The Summer Undergraduate Research Fellowship (SURF) Symposium

Photosynthesis is the basis of life on earth, and oxygen evolution catalysts are key components of this complicated, yet not fully understood process. Photosystem II, a large membrane bound pigment-protein complex, is the key system that facilitates oxygenic photosynthesis via the oxygen evolving complex (a natural oxygen evolving catalyst). It is a key component in oxygen producing catalysts, which can be used in fields such as energy production and biomimetic catalysts. The oxygen evolution cycle, or Kok cycle going within it is still not studied completely. In this project, we were studying the vibrational (and structural) state of a Manganese …

Palladium-Catalyzed Intramolecular Cross-Dehydrogenative Coupling: Synthesis Of Fused Imidazo[1,2‑A]Pyrimidines And Pyrazolo[1,5‑A]Pyrimidines, Siva K. Reddy Kotla, Jaya Kishore Vandavasi, Jeh-Jeh Wang, Keykavous Parang, Rakesh Tiwari

Pharmacy Faculty Articles and Research

A palladium-catalyzed intramolecular dehydrogenative coupling reaction was developed for the synthesis of fused imidazo[1,2-a]pyrimidines and pyrazolo[1,5-a]- pyrimidines. The developed protocol provides a practical approach for the synthesis of biologically important substituted pyrimidines from easily available substrates, with a broad substrate scope under mild reaction conditions.

Iron And Nickel Doped Cose2 As Efficient Non Precious Metal Catalysts For Oxygen Reduction, Beibei Yu, Jiayi Jin, Huimin Wu, Shengfu Wang, Qinghua Xia, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Iron and nickel doped CoSe2 were prepared by solvothermal method, and they were proved to be ternary chalcogenides by series of physical characterization. The effects of the iron and nickel contents on the oxygen reduction reaction were investigated by electrochemical measurements, and the highest activities were obtained on Co0.7Fe0.3Se2 and Co0.7Ni0.3Se2, respectively. Both Co0.7Fe0.3Se2 and Co0.7Ni0.3Se2 presented four-electron pathway. Furthermore, Co0.7Fe0.3Se2 exhibited more positive cathodic peak potential (0.564 V) and onset potential (0.759 V) than these of Co0.7Ni0.3Se2 (0.558 V and 0.741 V). And Co0.7Fe0.3Se2 displayed even superior stability and better tolerance to methanol, ethanol and ethylene glycol crossover effects …

Synthesis Of Structurally Ordered Platinum-Iron Catalysts With Enhanced Oxygen Reduction Reaction Activity, Ye-Zheng Cai, Ming-Chuan Luo, Fang-Hui Wang, Zhao-Nan Sun, Hong Zhu

Journal of Electrochemistry

To improve oxygen reduction reaction catalytic activity of the precious metals platinum for fuel cell, the precursors of carbon-supported structurally disordered platinum-iron alloy (D-Pt₃Fe/C and D-PtFe/C) catalysts with different compositions were synthesized via a modified polyol reduction method. Then, by optimizing the annealing conditions in the inert gas, we turned the structurally disordered platinum-iron alloy to the structurally ordered platinum-iron alloy (O-Pt₃Fe/C and O-PtFe/C) catalysts. The structural characterizations of the as-prepared catalysts were performed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The results …

Oxidative Dehydrogenation Of Propane Over V$_{2}$O$_{5}$ And K$_{2}$O-V$_{2}$O$_{5}$ Impregnated Mgal$_{2}$O$_{4}$Catalysts, Serkan Naci̇ Koç, Kübra Dayioğlu, Hasan Özdemi̇r

Turkish Journal of Chemistry

V$_{2}$O$_{5}$ and K$_{2}$O-V$_{2}$O$_{5}$ impregnated MgAl$_{2}$O$_{4}$ catalysts were prepared and tested for the oxidative dehydrogenation of propane. The as-synthesized catalysts were characterized by using the XRD, BET, NH$_{3}$-TPD, TPR, and XPS methods. The catalytic tests were performed in a fixed bed tubular quartz reactor system between 450 and 550 $^{\circ}$C. It was observed that the conversion of propane increased but hydrocarbon selectivity decreased with increasing temperature over the V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts. The BET surface area values and surface acidities decreased upon potassium addition for the K-V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts, which resulted in a drastic drop in the conversion values obtained. The propylene and total …

One Dimensional Graphitic Carbon Nitrides As Effective Metal-Free Oxygen Reduction Catalysts, Muhammad Nawaz Tahir, Nasir Mahmood, Jinghan Zhu, Asif Mahmood, Faheem K. Butt, Syed Rizwan, Imran Aslam, M Tanveer, Faryal Idrees, Imran Shakir, Chuanbao Cao, Yanglong Hou

Australian Institute for Innovative Materials - Papers

To explore the effect of morphology on catalytic properties of graphitic carbon nitride (GCN), we have studied oxygen reduction reaction (ORR) performance of two different morphologies of GCN in alkaline media. Among both, tubular GCN react with dissolved oxygen in the ORR with an onset potential close to commercial Pt/C. Furthermore, the higher stability and excellent methanol tolerance of tubular GCN compared to Pt/C emphasizes its suitability for fuel cells.

Gold Nanocrystals With Variable Index Facets As Highly Effective Cathode Catalysts For Lithium-Oxygen Batteries, Dawei Su, S X. Dou, Guoxiu Wang

Australian Institute for Innovative Materials - Papers

Cathode catalysts are the key factor in improving the electrochemical performance of lithium-oxygen (Li-O2) batteries via their promotion of the oxygen reduction and oxygen evolution reactions (ORR and OER). Generally, the catalytic performance of nanocrystals (NCs) toward ORR and OER depends on both composition and shape. Herein, we report the synthesis of polyhedral Au NCs enclosed by a variety of index facets: cubic gold (Au) NCs enclosed by {100} facets; truncated octahedral Au NCs enclosed by {100} and {110} facets; and trisoctahedral (TOH) Au NCs enclosed by 24 high-index {441} facets, as effective cathode catalysts for Li-O2 batteries. All Au …

One-Dimensional Manganese-Cobalt Oxide Nanofibres As Bi-Functional Cathode Catalysts For Rechargeable Metal-Air Batteries, Kyu-Nam Jung, Soomin Hwang, Min-Sik Park, Ki Jae Kim, Jae-Geun Kim, S X. Dou, Jung Ho Kim, Jongwon Lee

Australian Institute for Innovative Materials - Papers

Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the …

Mechanistic Insights And Functionalization Of Alkynes In Homogeneous Gold Catalysis., Manish Kumar

Electronic Theses and Dissertations

The focus of my dissertation work was to study the basic mechanistic insights of gold-catalyzed reactions. Although the various mechanistic pathways of gold catalysis are better understood nowadays, numerous questions still remain unanswered concerning the nature of deactivation of the catalyst's active species, high resistance towards protodeauration, and how we can solve these problems to improve the efficiency of gold catalysis. To address these challenges in gold catalysis we conducted first a detailed experimental study to understand the mechanism of deactivation of gold active species. Based on the combination of experimental data, we proposed that gold disproportionation is preferred as …

Fabrication Of Multifunctional Ferromagnetic Au₃Pd-Cose Nanoparticles, Wipula P. Liyanage, Sukhada Mishra, Kai Song, Manashi Nath

Chemistry Faculty Research & Creative Works

We have synthesized multifunctional anisotropic Au₃Pd-CoSe nanoparticles on Si substrate through a catalyst aided chemical vapour deposition technique. the technique utilized volatile cobalt acetylacetonate and elemental selenium as precursors while sputter coated Au-Pd (3:2) film acted as a catalyst. the typical growth conditions led to clear segregation of the hetero-compositions (i.e. Au₃Pd and CoSe) in the product nanostructures thereby preserving the functionality of both the phases. the degree of crystallinity of the individual phases in the composite nanostructure was fairly high. the bifunctional nanoparticles show soft ferromagnetic behaviour at room temperature and optical activity making them …

Expanding The Frontier Of Gold-Catalyzed Cyclizations And Rational Ligand Design., Deepika Malhotra

Electronic Theses and Dissertations

The focus of my dissertation work is to study the gold-catalyzed intramolecular and intermolecular cyclizations involving oxonium intermediates towards the application of synthetically interesting frameworks under ambient conditions and developing a rational approach for the effective catalyst design in gold catalysis. We explored the goldcatalyzed oxygen-transfer reactions of 2-alkynyl-1,5-diketones or 2-alkynyl-5-ketoesters to furnish five-membered rings bearing a quaternary carbon tethered to a carbonyl group. The detailed mechanistic investigation on the newly proposed intramolecular [4+2] cycloaddition mechanism was performed by means of isotopic experiments and quantum chemical calculations. The reactivity of alkynylenolate was investigated in the reactions of allenic ketones and …

Mono-Sized Sphere Packing Algorithm Development Using Optimized Monte Carlo Technique, Karn Soontrapa, Yitung Chen

College of Engineering: Graduate Celebration Programs

In this research, fuel cell catalyst layer was developed using the optimized sphere packing algorithm. An optimization technique named adaptive random search technique (ARSET) was employed in this packing algorithm. The ARSET algorithm will generate the initial location of spheres and allow them to move in the random direction with the variable moving distance, randomly selected from the sampling range (a), based on the Lennard–Jones potential and Morse potential of the current and new configuration. The solid fraction values obtained from this developed algorithm are in the range of 0.610–0.624 while the actual processing time can significantly be reduced by …

Catalysts For Stone Age Innovations: What Might Have Triggered Two Short-Lived Bursts Of Technological And Behavioral Innovation In Southern Africa During The Middle Stone Age?, Richard Roberts, Zenobia Jacobs

Richard G Roberts

No abstract provided.

Catalytic Solar Water Splitting Inspired By Photosynthesis. Homogeneous Catalysts With A Mechanical ("Machine-Like") Action, Gerhard F. Swiegers, G Charles Dismukes, Leone Spiccia, Robin Brimblecombe, Annette Koo, Jun Chen, Gordon G. Wallace

Gordon Wallace

Chemical reactions may be controlled by either: the minimum threshold energy that must be overcome during collisions between reactant molecules / atoms (the Activation Energy, Ea), or: the rate at which reactant collisions occur (the Collision Frequency, A) (for reactions with low Ea). Reactions of type (2) are governed by the physical, mechanical interaction of the reactants. Such mechanical processes are unusual, but not unknown in molecular catalysts. We examine the catalytic action and macroscopic properties of several abiological mechanical catalysts and show that they display distinct similarities to enzymes in general. An abiological model of the Photosystem II Water …

Brust-Schiffrin Synthesis Of Catalytic Bipodal Pdpt Nanoparticles With Some Mechanistic Insights, Sangbum Han, Vara P. Sheela, Wei Cao, Balasubramanian Ramjee

Applied Research Center Publications

Brust–Schiffrin reduction of Pd and Pt precursors in the presence of resorcinarene amine surfactant led to the formation of substantially Pt rich, PdPt bimetallic nanoparticles of a V-shape or variants on the V-shape. New insights into this reaction are provided on the basis of reversed Brust–Schiffrin syntheses, DLS, UV-vis, and NMR analysis. Based on our experiments we conclude that the resorcinarene amine surfactant is part of the inverse micelle formed from TOABr and it also selectively complexes with the Pd salts prior to their reduction. Remarkably, the composition of the bipodal nanoparticles could be varied substantially by varying the reaction …

Synthesis And Characterization Of Catalysts For The Selective Transformation Of Biomass-Derived Materials, Isaac Tyrone Ghampson

Electronic Theses and Dissertations

The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silicasupported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, …

Ruthenium-Based Olefin Metathesis Catalysts Bearing Ph-Responsive Ligands: External Control Of Catalyst Solubility And Activity, Shawna Lynn Balof

Dissertations

Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe₂) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media.

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