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Full-Text Articles in Physical Sciences and Mathematics

Nsf Career Award Supports Schwartz's Research On The Chemical Process For Making Rubber Component, Marcus Wolf Mar 2021

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.


Composite Zeolite Beta Catalysts For Catalytic Hydrocracking Of Plastic Waste To Liquid Fuels, Dureem Munir, Hassaan Amer, Rabya Aslam, Mohamed Bououdina, Muhammad Rashid Usman Apr 2020

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 Oct 2019

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 Jan 2019

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 …


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 Jan 2019

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 …


Development Of Bifunctional Thiourea Catalysts For Effective Direct Amidation Reactions, Alex Guzman Jan 2018

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 …


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 Jan 2017

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 Jan 2017

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 …


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 Jan 2015

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 Jan 2015

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 Jan 2015

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 …


Fabrication Of Multifunctional Ferromagnetic Au₃Pd-Cose Nanoparticles, Wipula P. Liyanage, Sukhada Mishra, Kai Song, Manashi Nath Jun 2014

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 …


Brust-Schiffrin Synthesis Of Catalytic Bipodal Pdpt Nanoparticles With Some Mechanistic Insights, Sangbum Han, Vara P. Sheela, Wei Cao, Balasubramanian Ramjee Jan 2013

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 …


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 Jan 2010

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

Faculty of Science - Papers (Archive)

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 …


Molecular Water Oxidation Catalysts For Photoelectrochemical Cells, Robin Brimblecombe, Charles Dismukes, Gerhard F. Swiegers, Leone Spiccia Jan 2009

Molecular Water Oxidation Catalysts For Photoelectrochemical Cells, Robin Brimblecombe, Charles Dismukes, Gerhard F. Swiegers, Leone Spiccia

Faculty of Science - Papers (Archive)

Photoelectrochemical cells that efficiently split water into oxygen and hydrogen, "the fuel of the future", need to combine robust water oxidation catalysts at the anode (2H(2)O -> O-2 + 4H(+) + 4e(-)) with hydrogen reduction catalysts at the cathode (2H(+) + 2e(-) -> H-2). Both sets of catalysts will, ideally, operate at low overpotentials and employ light-driven or light-assisted processes. In this Perspective article, we focus on significant efforts to develop solid state materials and molecular coordination complexes as catalyst for water oxidation. We briefly review the field with emphasis on the various molecular catalysts that have been developed and …


Synthesis And Characterization Of Dendrimer Templated Supported Bimetallic Pt-Au Nanoparticles, Huifang Lang, S. Maldonado, K. J. Stevenson, Bert D. Chandler Sep 2004

Synthesis And Characterization Of Dendrimer Templated Supported Bimetallic Pt-Au Nanoparticles, Huifang Lang, S. Maldonado, K. J. Stevenson, Bert D. Chandler

Chemistry Faculty Research

Bimetallic dendrimer-stabilized nanoparticles (DSNs) were used to prepare supported Pt-Au catalysts within the bulk miscibility gap for this binary system. Hydroxy-terminated generation 5 PAMAM dendrimers were used to prepare Cu0 nanoparticles (NPs). The Cu0 NPs were subsequently used to reduce K2PtCl4 and HAuCl4, preparing stabilized bimetallic Pt-Au NPs with a 1:1 stoichiometry. The stabilized NPs were adsorbed onto a high surface area silica support and thermally activated to remove the dendrimers. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and infrared spectroscopy of adsorbed CO showed that this preparation route resulted in NPs in …