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https://www.readbyqxmd.com/read/28454074/photocatalytic-degradation-of-dye-using-ceo2-scb-composite-catalysts
#1
Duangdao Channei, Auppatham Nakaruk, Sukon Phanichphant
The main task of the present work is to enhance the photocatalytic degradation efficiency of methylene blue (MB) by using CeO2/sugarcane bagasse (SCB) composite catalysts. Homogeneous precipitation method was used to synthesis CeO2-SCB composite catalysts by adding SCB powder to precursor solution of Ce base-metal. The structural analytical data indicated the pure cubic fluorite structure of CeO2. Morphological images revealed the coating of CeO2 layer on high surface area of SCB core-shell. The chemical analysis presented spectrum of the Ce 3d in CeO2/SCB sample existed in the form of the Ce(3+) and Ce(4+) mixed- valence states...
April 22, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28454046/preliminary-investigation-of-catalytic-antioxidant-anticancer-and-bactericidal-activity-of-green-synthesized-silver-and-gold-nanoparticles-using-actinidia-deliciosa
#2
Saraschandra Naraginti, Yi Li
Herein we report a rapid low cost one step green synthetic method using Actinidia deliciosa fruit extract for preparation of stable and multifunctional silver and gold nanoparticles. The synthesized nanoparticles were successfully used as green catalysts for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB). The enhanced biological activity of the prepared nanoparticles was investigated based on its highly stable antioxidant, anticancer and bactericidal effects. TEM micrographs showed that the silver nanoparticles (AgNPs) formed were predominantly spherical in shape having diameters ranging from 25 to 40nm, while gold nanoparticles (AuNPs) shown particle size ranges from 7 to 20nm...
March 30, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28453982/effect-of-microstructure-and-surface-hydroxyls-on-the-catalytic-activity-of-au-alooh-for-formaldehyde-removal-at-room-temperature
#3
Zhaoxiong Yan, Zhihua Xu, Jiaguo Yu, Mietek Jaroniec
A series of Au/AlOOH catalysts was prepared by impregnating different AlOOH supports with Au precursor followed by NaBH4-assisted reduction, and examined their activity toward oxidation of indoor formaldehyde (HCHO) pollutant at room temperature. The AlOOH supports used were synthesized by microemulsion, microwave and hydrothermal methods. Among these supports the catalyst obtained by deposition of Au nanoparticles (NPs) on AlOOH prepared by microemulsion method (Au/AlOOH-m) exhibited the highest catalytic activity...
April 19, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28453981/facile-synthesis-of-flower-like-ag3vo4-bi2wo6-heterojunction-with-enhanced-visible-light-photocatalytic-activity
#4
Shijie Li, Shiwei Hu, Wei Jiang, Yu Liu, Jianshe Liu, Zhaohui Wang
Constructing novel semiconductor heterojunctions is one of the most significant approaches to improving the photocatalytic performance of a photocatalyst. Herein, the Ag3VO4/Bi2WO6 heterojunction was prepared through in-situ anchoring Ag3VO4 nanoparticles (size: ∼21nm) on the surface of Bi2WO6 microflowers (diameter: 2.5-4.5μm) by a facile deposition route. The photocatalytic activity of these heterojunctions were studied by decomposing cationic dye rhodamine B (RhB), anionic dye methyl orange (MO) and neutral para-chlorophenol (4-CP) under visible light irradiation (λ>400nm)...
April 20, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28453926/fluoropolymer-stabilized-chromophore-catalyst-assemblies-in-aqueous-buffer-solutions-for-water-oxidation-catalysis
#5
Michael S Eberhart, Kyung-Ryang Wee, Degao Wang, Seth Marquard, Kasey Skinner, Animesh Nayak, Thomas J Meyer
We describe here application of the fluorinated polymer (Dupont AF, a copolymer of 4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole and tetrafluoroethylene) in stabilizing phosphonate-derivatized molecular assemblies on oxide electrodes. In the procedure, the polymer is dip coated onto the surfaces of oxide electrodes with pre-bound, phosphonate-derivatized chromophores and assemblies including assemblies for water oxidation. The results of our experiments demonstrate a high degree of stabilization by the added polymer and a demonstration of its use in stabilizing surface-bound assemblies for water oxidation catalysis...
April 28, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28453290/enantioselective-intermolecular-addition-of-aliphatic-amines-to-acyclic-dienes-with-a-pd-phox-catalyst
#6
Nathan J Adamson, Ethan Hull, Steven J Malcolmson
We report a method for the catalytic, enantioselective intermolecular addition of aliphatic amines to acyclic 1,3-dienes. In most cases, reactions proceed efficiently at or below room temperature in the presence of 5 mol % of a Pd catalyst bearing a PHOX ligand, generating allylic amines in up to 97:3 er. The presence of an electron-deficient phosphine within the ligand not only leads to a more active catalyst but is also critical for achieving high site-selectivity in the transformation.
April 28, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28453268/ir-catalyzed-ortho-borylation-of-phenols-directed-by-substrate-ligand-electrostatic-interactions-a-combined-experimental-in-silico-strategy-for-optimizing-weak-interactions
#7
Buddhadeb Chattopadhyay, Jonathan E Dannatt, Ivonne L Andújar-de Sanctis, Kristin A Gore, Robert E Maleczka, Daniel A Singleton, Milton R Smith
A strategy for affecting ortho versus meta/para selectivity in Ir-catalyzed C-H borylations (CHBs) of phenols is described. From selectivity observations with ArylOBpin (pin = pinacolate), it is hypothesized that an electrostatic interaction between the partial negatively charged OBpin group and the partial positively charged bipyridine ligand of the catalyst favors ortho selectivity. Experimental and computational studies designed to test this hypothesis support it. From further computational work a second generation, in silico-designed catalyst emerged, where replacing Bpin with Beg (eg = ethylene glycolate) was predicted to significantly improve ortho selectivity...
April 28, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28453262/periodic-trends-in-olefin-epoxidation-over-group-iv-and-v-framework-substituted-zeolite-catalysts-a-kinetic-and-spectroscopic-study
#8
Daniel T Bregante, David W Flaherty
Group IV and V framework substituted zeolites have been used for olefin epoxidation reactions for decades, yet the under-lying properties that determine the selectivities and turnover rates of these catalysts have not yet been elucidated. Here, a combination of kinetic, thermodynamic, and in situ spectroscopic measurements show that when group IV (i.e., Ti, Zr, and Hf) or V (i.e., Nb and Ta) transition metals are substituted into zeolite *BEA, the metals that form stronger Lewis acids give greater selectivities and rates for the desired epoxidation pathway and present smaller enthalpic barriers for both epoxida-tion and H2O2 decomposition reactions...
April 28, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28449245/characterization-of-a-poly-4-vinylpyridine-supported-cupd-bimetallic-catalyst-for-sonogashira-coupling-reactions
#9
Claudio Evangelisti, Antonella Balerna, Rinaldo Psaro, Graziano Fusini, Adriano Carpita, Maurizio Benfatto
CuPd bimetallic Solvated Metal Atoms (SMA) synthesized by metal vapor synthesis (MVS) technique and supported on poly-4-vinylpyridine (PVPy) resin, showed signicantly higher catalytic activity in Sonogashira-type carbon-carbon coupling reactions than the corresponding monometallic Cu and Pd systems as well as their physical mixture. The analysis of the bimetallic catalyst combining high-resolution transmission electron microscopy (HRTEM) and x-ray absorption ne structure (XAFS) spectroscopy revealed the presence of small Pd nanoparticles (dm = 2...
April 27, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28449230/metal-free-arene-and-heteroarene-borylation-catalyzed-by-strongly-electrophilic-bis-boranes
#10
Gerhard Erker, Yun-Lin Liu, Gerald Kehr, Constantin G Daniliuc
The geminal chelate bis-borylalkanes 4 and 5 featuring strongly electrophilic B(C6F5)2 and B(C6F5) groups, respectively, serve as efficient catalysts for the borylation of arenes and heteroarenes. The borylation reactions proceed under mild conditions with liberation of dihydrogen.
April 27, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28448969/synthetic-switchable-enzymes
#11
Vic Norris, Sergey N Krylov, Pratul K Agarwal, Glenn J White
The construction of switchable, radiation-controlled, aptameric enzymes - "swenzymes" - is, in principle, feasible. We propose a strategy to make such catalysts from 2 (or more) aptamers each selected to bind specifically to one of the substrates in, for example, a 2-substrate reaction. Construction of a combinatorial library of candidate swenzymes entails selecting a set of a million aptamers that bind one substrate and a second set of a million aptamers that bind the second substrate; the aptamers in these sets are then linked pairwise by a linker, thus bringing together the substrates...
April 28, 2017: Journal of Molecular Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28448155/cp-co-iii-catalyzed-annulation-of-carboxylic-acids-with-alkynes
#12
Rajib Mandal, Basker Sundararaju
A new procedure for oxidative coupling of aromatic and acrylic acids with alkynes has been developed using abundant, nontoxic, and air stable Cp*Co(III) catalyst. The coupling involves initial cyclometalation via weak chelation-assisted C-H bond activation followed by alkyne coordination, insertion, and reductive elimination leading to diverse isocoumarins (α-pyranones) in good yields under mild conditions.
April 27, 2017: Organic Letters
https://www.readbyqxmd.com/read/28448127/organo-copper-ii-complexes-as-products-of-radical-atom-transfer
#13
Timothy J Zerk, Paul V Bernhardt
Copper complexes bearing polyamine chelate ligands are among the most widely used and highly active catalysts for atom transfer radical polymerization (ATRP). Copper(I) complexes of these ligands (Cu(I)L) react with an alkyl halide initiator (RX) in the atom transfer step to generate the higher oxidation state halido complex Cu(II)LX and the radical R(•). However, Cu(I)L present in the reaction also has the potential to react with the liberated radicals to generate the organometallic species Cu(II)LR (where R is formally a carbanion)...
April 27, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28448126/from-surprising-solvothermal-reaction-to-uncommon-zinc-ii-catalyzed-aromatic-c-h-activation-reaction-for-direct-nitroquinoline-synthesis
#14
Yazhen Wang, Feihu Yu, Xiao Han, Ming Li, Yue Tong, Jie Ding, Hongwei Hou
In this work, we first found a surprising solvothermal reaction for direct dinitration of quinoline derivative. To explore the application in direct nitroquinoline synthesis, this reaction was subsequently modified as an equivalent reaction in a Schlenk tube. More significantly, after a constant attempt, nitrated derivative was obtained in optimized condition with a zinc(II) sulfate catalyst, where some substrates with strong electron-withdrawing group were first nitrated by a directly catalyzed condition. This new zinc(II)-catalyzed aromatic C-H activation reaction is the first example of direct dinitration by a single catalyst, which will be a new facile and environmentally friendly strategy to access synthetically useful nitroquinoline derivative...
April 27, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28447880/resistance-training-in-youth-laying-the-foundation-for-injury-prevention-and-physical-literacy
#15
Christin Zwolski, Catherine Quatman-Yates, Mark V Paterno
CONTEXT: The rising incidence of physical activity- and sports-related injuries has prompted the present-day investigation of resistance training as a potential means of injury prevention and physical literacy development among youth. EVIDENCE ACQUISITION: Relevant studies on the topics of athlete development, physical literacy, resistance training, and injury prevention in children and adolescents were reviewed (PubMed and Sports Discus, 1982-2016). Recommendations from consensus guidelines and position statements applicable to resistance training and injury prevention in youth, in addition to young athlete development, were reviewed...
April 1, 2017: Sports Health
https://www.readbyqxmd.com/read/28447796/rhodium-catalyzed-asymmetric-conjugate-alkynylation-of-%C3%AE-%C3%AE-unsaturated-%C3%AE-ketoesters
#16
Yanle Zhi, Jianhang Huang, Na Liu, Tao Lu, Xiaowei Dou
The first example of catalytic asymmetric conjugate alkynylation of β,γ-unsaturated α-ketoesters is reported. By using Rh(I)/(R)-DM-binap complex as the catalyst and diphenyl[(triisopropylsilyl)ethynyl]methanol as the alkynylating reagent, the alkynylation reaction proceeded smoothly to afford α-ketoesters bearing a propargylic chiral center at γ position in good yields with high enantioselectivities.
April 27, 2017: Organic Letters
https://www.readbyqxmd.com/read/28447779/performance-and-mechanism-of-piezo-catalytic-degradation-of-4-chlorophenol-finding-of-effective-piezo-dechlorination
#17
Shenyu Lan, Jinxi Feng, Ya Xiong, Shuanghong Tian, Shengwei Liu, Lingjun Kong
Piezo-catalysis was first used to degrade a non-dye pollutant, 4-chlorophenol (4-CP). In this process, hydrothermally synthesized tetragonal BaTiO3 nano/micrometer-sized particles were used as the piezo-catalyst and the ultrasonic irradiation with low frequency was selected as the vibration energy to cause the deformation of tetragonal BaTiO3. It was found that the piezoelectric potential from the deformation could not only successfully degrade 4-chlorophenol, but also effectively make it dechlorination at the same time...
April 27, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28447774/nitrogen-and-phosphorus-codoped-mesoporous-carbon-derived-from-polypyrrole-as-superior-metal-free-electrocatalyst-towards-the-oxygen-reduction-reaction
#18
Zhengping Zhang, Junting Sun, Meiling Dou, Jing Ji, Feng Wang
To replace high-cost platinum group metal (PGM) electrocatalysts for oxygen reduction reaction (ORR) that is the crucial cathode reaction in fuel cell technology and metal-air battery, the development of low-cost and high-efficiency non-PGM catalysts for ORR has attracted much attention during the past decades. As one of the promising candidates, the N-doped carbon is highly desirable for its strong designability and outstanding catalytic activity and stability. In this work, a facile and rational strategy is demonstrated for preparation of N, P-codoped mesoporous carbon (N,P-MC) for ORR by the direct pyrolysis treatment of polypyrrole with phytic acid as P-dopant and polystyrene sphere as template...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28447700/evolution-inspired-engineering-of-antibiotic-biosynthesis-enzymes
#19
M Metsä-Ketelä
Streptomyces soil bacteria are competent chemists that are able to produce thousands of chemically complex natural products. Key to the development of this rich source of metabolites appears to be an evolutionary pressure that promotes chemical diversity; new biosynthetic pathways are continuously being formed in these bacteria, which may result in the appearance of a novel bioactive compound that provides significant competitive advantage to the producing organism. In recent years, our work has focused on understanding how minor changes in the biosynthetic enzymes has led to drastically altered catalytic properties...
April 27, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28447696/photocatalytic-photosystem-i-pedot-composite-films-prepared-by-vapor-phase-polymerization
#20
M T Robinson, C E Simons, D E Cliffel, G K Jennings
Photosystem I (PSI) achieves photo-induced charge separation with outstanding internal quantum efficiency and has been used to improve the performance of various photoelectrochemical systems. Herein, we describe a fast and versatile technique to assemble composite films containing PSI and a chosen intrinsically conductive polymer (ICP). A mixture of PSI and a Friedel-Crafts catalyst (FeCl3) is drop cast atop a substrate of choice. Contact with ICP monomer vapor at low temperature stimulates polymer growth throughout PSI films in minutes...
April 27, 2017: Nanoscale
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