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https://www.readbyqxmd.com/read/28219034/preparation-of-core-shell-nanostructure-fe3o4-peg400-so3h-as-heterogeneous-and-magnetically-recyclable-nanocatalyst-for-one-pot-synthesis-of-substituted-pyrroles-by-paal-knorr-reaction-at-room-temperature
#1
Fahimeh Bonyasi, Malak Hekmati, Hojat Veisi
An efficient procedure has been proposed for the loading of sulfonic acid groups on the surface of polyethylene glycol 400 (PEG400)-encapsulated Fe3O4 nanoparticles to synthesize a core-shell Fe3O4@PEG400-SO3H nano catalyst. Surface functionalization of magnetic particles in such a way is a refined method of bridging the gap amongst heterogeneous and homogeneous catalysis. The procured nano catalyst was classified through Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), BET, and back titration...
February 13, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28203654/the-effect-of-varying-solvents-for-mos2-treatment-on-its-catalytic-efficiencies-for-her-and-orr
#2
Xing Juan Chua, Martin Pumera
MoS2 has been investigated intensively in the field of catalysis for the hydrogen evolution reaction (HER) in particular. Much effort has been made by various research teams worldwide to look into the specific catalyst design such as nano-structuring, defect engineering or hybrid structures. But what evades us is the fundamental preparation method for the dispersion of powdered MoS2. Individual research teams with their best practices might be subjective and not validated by extensive experimental results. In this report, we find that the overpotential for the catalysis of HER varies from 0...
February 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28195390/self-assembly%C3%A2-of%C3%A2-renewable%C3%A2-nano-sized-triterpenoids
#3
REVIEW
Braja Gopal Bag, Rakhi Majumdar
Studies on plant metabolites have gained renewed interest in recent years because these can serve as renewable chemicals for the development of a sustainable society.Among various plant secondary metabolites, terpenoids constitute the major component and triterpenoids are the 30C subset of it.In recent years, triterpenoids have drawn the attention of scientific community due to many of its potential and realized applications in medicine, drug delivery, thermochromic materials, pollutant capture, catalysis, liquid crystals, etc...
February 14, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28156099/shape-controllable-gold-nanoparticles-mos2-hybrids-prepared-by-tuning-edge-active-sites-and-surface-structures-of-mos2-via-temporally-shaped-femtosecond-pulses
#4
Pei Zuo, Lan Jiang, Xin Li, Bo Li, Yongda Xu, Xuesong Shi, Peng Ran, Tianbao Ma, Dawei Li, Liangti Qu, Yongfeng Lu, Costas P Grigoropoulos
Edge-active site control of MoS2 is crucial for applications such as chemical catalysis, synthesis of functional composites, and biochemical sensing. This work presents a novel nonthermal method to simultaneously tune surface chemical (edge-active sites) and physical (surface periodic micro/nano structures) properties of MoS2 using temporally shaped femtosecond pulses, through which shape-controlled gold nanoparticles are in situ and self-assembly grown on MoS2 surfaces to form Au-MoS2 hybrids. The edge-active sites with unbound sulfurs of laser-treated MoS2 drive the reduction of gold nanoparticles, while the surface periodic structures of laser-treated MoS2 assist the shape-controllable growth of gold nanoparticles...
February 3, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28147552/a-practical-approach-to-the-sensitivity-analysis-for-kinetic-monte-carlo-simulation-of-heterogeneous-catalysis
#5
Max J Hoffmann, Felix Engelmann, Sebastian Matera
Lattice kinetic Monte Carlo simulations have become a vital tool for predictive quality atomistic understanding of complex surface chemical reaction kinetics over a wide range of reaction conditions. In order to expand their practical value in terms of giving guidelines for the atomic level design of catalytic systems, it is very desirable to readily evaluate a sensitivity analysis for a given model. The result of such a sensitivity analysis quantitatively expresses the dependency of the turnover frequency, being the main output variable, on the rate constants entering the model...
January 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28124047/adatom-surface-diffusion-of-catalytic-metals-on-the-anatase-tio2-101-surface
#6
Afnan Alghannam, Christopher L Muhich, Charles B Musgrave
Titanium oxide is often decorated with metal nano-particles and either serves as a catalyst support or enables photocatalytic activity. The activity of these systems degrades over time due to catalytic particle agglomeration and growth by Ostwald ripening where adatoms dissociate from metal particles, diffuse across the surface and add to other metal particles. In this work, we use density functional theory calculations to study the diffusion mechanisms of select group VIII and 1B late-transition metal adatoms commonly used in catalysis and photocatalysis (Au, Ag, Cu, Pt, Rh, Ni, Co and Fe) on the anatase TiO2(101) surface...
January 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28106897/transition-metal-co-ni-nanoparticles-wrapped-with-carbon-and-their-superior-catalytic-activities-for-the-reversible-hydrogen-storage-of-magnesium-hydride
#7
Xu Huang, Xuezhang Xiao, Wei Zhang, Xiulin Fan, Liuting Zhang, Changjun Cheng, Shouquan Li, Hongwei Ge, Qidong Wang, Lixin Chen
Magnesium hydride (MgH2) exhibits long-term stability and has recently been developed as a safe alternative to store hydrogen in the solid state, due to its high capacity of 7.6 wt% H2 and low cost compared to other metal hydrides. However, the high activation energy and poor kinetics of MgH2 lead to inadequate hydrogen storage properties, resulting in low energy efficiency. Nano-catalysis is deemed to be the most effective strategy in improving the kinetics performance of hydrogen storage materials. In this work, robust and efficient architectures of carbon-wrapped transition metal (Co/C, Ni/C) nanoparticles (8-16 nm) were prepared and used as catalysts in the MgH2 system via ball milling to improve its de/rehydrogenation kinetics...
February 1, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098801/a-novel-antihypertensive-derived-from-adlay-coix-larchryma-jobi-l-var-ma-yuen-stapf-glutelin
#8
Bin Li, Liansheng Qiao, Lingling Li, Yanling Zhang, Kai Li, Lingzhi Wang, Yanjiang Qiao
Our previous studies have shown that Coix glutelin pepsin hydrolysate can effectively inhibit angiotensin converting enzyme (ACE) activity in vitro. The main purpose of this study was to obtain potent anti-hypertensive peptides from Coix glutelin. The Coix glutelin hydrolysates (CGH) were prepared by pepsin catalysis and further separated by an ultrafitration (UF) system, gel filtration chromatography (GFC) and reversed-phase high performance liquid chromatography (RP-HPLC). As a result, the sub-fraction F5-3 had the highest ACE-inhibitory activity...
January 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28098191/be12o12-nano-cage-as-a-promising-catalyst-for-co2-hydrogenation
#9
Haiyan Zhu, Yawei Li, Guizhi Zhu, Haibin Su, Siew Hwa Chan, Qiang Sun
An efficient conversion of CO2 into valuable fuels and chemicals has been hotly pursued recently. Here, for the first time, we have explored a series of M12x12 nano-cages (M = B, Al, Be, Mg; X = N, P, O) for catalysis of CO2 to HCOOH. Two steps are identified in the hydrogenation process, namely, H2 activation to 2H*, and then 2H* transfer to CO2 forming HCOOH, where the barriers of two H* transfer are lower than that of the H2 activation reaction. Among the studied cages, Be12O12 is found to have the lowest barrier in the whole reaction process, showing two kinds of reaction mechanisms for 2H* (simultaneous transfer and a step-wise transfer with a quite low barrier)...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28081001/how-assembly-matters-to-catalysis-and-thermal-conductivity-mediated-by-cuo-nanoparticles
#10
Ahmed Mohsen Ismail, Mahmoud Mohamed Emara, Taher Salah El Din Kassem, Mahmoud Ahmed Moussa
CuO nanostructures (NSs) of different morphologies were prepared, applied as catalysts for the pyrolysis of sugarcane bagasse (PSCB), and applied for thermally-conductive nanofluids. Both size and shape of the prepared NSs ranged from 5 to 1000 nm, and from nanodots (NDs) to spindle nano-aggregates (NAs), respectively. The catalytic activity of these NSs towards the PSCB was followed up by thermogravimetric analysis (TGA), where they increased the percentage of total weight loss, and lowered the decomposition temperatures of PSCB...
January 12, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28064093/hybrid-nano-composites-made-of-ss-dna-wrapped-carbon-nanotubes-and-titania
#11
Martina Romio, Camillo La Mesa
Multi-walled carbon nanotubes, MWCNTs, are stabilized thanks to the surface wrapping of single-strand DNA, ss-DNA; the resulting adducts are kinetically and thermodynamically stable Such entities build up nano-hybrids with titania, TiO2, nano-particles, in presence of surfactant as an adjuvant. The conditions leading to TiO2 adsorption onto ss-DNA/CNTs were investigated, by optimizing the concentration of adducts, nano-particles (NPs), and of the cationic surfactant (CTAB). Controlling the working conditions makes possible to get homogeneously organized hybrids...
December 24, 2016: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28061527/covalent-functionalization-of-organic-nanoparticles-using-aryl-diazonium-chemistry-and-their-solvent-dependent-self-assembly
#12
Sreedevi Krishnakumar, Karical R Gopidas
A simple method for covalent functionalization of Fréchet-type dendron nanoparticles (FDNs) using tris-bipyridylruthenium(II) is described. Covalent functionalization is achieved by chemically reducing the diazo derivative of a ruthenium(II)bipyridine complex in the presence of FDNs wherein the radical species generated gets covalently linked to the nanoparticle surface. Simplicity, rapidity, and robustness are the advantages offered by the present approach. The nanoparticles, post functionalization, were characterized using transmission electron microscopy, thermogravimetric analysis, and infrared, energy-dispersive X-ray, UV-visible, and nuclear magnetic resonance spectroscopic techniques...
January 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28024334/functionalized-nano-mos2-with-peroxidase-catalytic-and-near-infrared-photothermal-activities-for-safe-and-synergetic-wound-antibacterial-applications
#13
Wenyan Yin, Jie Yu, Fengting Lv, Liang Yan, Li Rong Zheng, Zhanjun Gu, Yuliang Zhao
We have developed a biocompatible antibacterial system based on polyethylene glycol functionalized molybdenum disulfide nanoflowers (PEG-MoS2 NFs). The PEG-MoS2 NFs have high near-infrared (NIR) absorption and peroxidase-like activity, which can efficiently catalyze decomposition of low concentration of H2O2 to generate hydroxyl radicals (·OH). The conversion of H2O2 into ·OH can avoid the toxicity of high concentration of H2O2 and the ·OH has higher antibacterial activity, making resistant bacteria more vulnerable and wounds more easily cured...
December 27, 2016: ACS Nano
https://www.readbyqxmd.com/read/28024190/self-assembly-of-multi-hierarchically-structured-spongy-mesoporous-silica-particles-and-mechanism-of-their-formation
#14
V Kalaparthi, S Palantavida, N E Mordvinova, O I Lebedev, I Sokolov
Here we report on self-assembly of novel multi-hierarchically structured meso(nano)porous colloidal silica particles which have cylindrical pores of 4-6nm, overall size of ∼10μm and "cracks" of 50-200nm. These cracks make particles look like micro-sponges. The particles were prepared through a modified templated sol-gel self-assembly process. The mechanism of assembly of these particles is investigated. Using encapsulated fluorescent dye, we demonstrate that the spongy particles are advantageous to facilitate dye diffusion out of particles...
December 18, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28010061/self-templating-construction-of-3d-hierarchical-macro-mesoporous-silicon-from-0d-silica-nanoparticles
#15
Xiuxia Zuo, Yonggao Xia, Qing Ji, Xiang Gao, Shanshan Yin, Meimei Wang, Xiaoyan Wang, Bao Qiu, Anxiang Wei, Zaicheng Sun, Zhaoping Liu, Jin Zhu, Ya-Jun Cheng
Porous silicon has found wide applications in many different fields including catalysis and lithium-ion batteries. Three-dimensional hierarchical macro-/mesoporous silicon is synthesized from zero-dimensional Stöber silica particles through a facile and scalable magnesiothermic reduction process. By systematic structure characterization of the macro-/mesoporous silicon, a self-templating mechanism governing the formation of the porous silicon is proposed. Applications as lithium-ion battery anode and photocatalytic hydrogen evolution catalyst are demonstrated...
December 28, 2016: ACS Nano
https://www.readbyqxmd.com/read/27980985/a-porous-metal-organic-framework-assembled-by-cu30-nanocages-serving-as-recyclable-catalysts-for-co2-fixation-with-aziridines
#16
Hang Xu, Xiao-Fang Liu, Chun-Shuai Cao, Bin Zhao, Peng Cheng, Liang-Nian He
Based on a novel ligand 5-(2,6-bis(4-carboxyphenyl)pyridin-4-yl)isophthalic acid (H4BCP) with large skeletons, a unique porous framework {[Cu2(BCP)(H2O)2]·3DMF} n (1) assembled by nano-sized and censer-like [Cu30] cages is successfully obtained and structurally characterized. In 1, the large 1D channel in frameworks and window size in the nanocages can enrich methylene blue and capture CO2, exhibiting the promising applications in environmental protection. More importantly, the explorations on the cycloaddition reaction of CO2 and aziridines with various substituents suggest that 1 can serve as an efficient heterogeneous catalyst for CO2 conversion with aziridines in a solvent-free system, which can be reused at least ten times without any obvious loss in catalytic activity...
November 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://www.readbyqxmd.com/read/27933762/nanocomputed-tomography-imaging-of-bacterial-alkaline-phosphatase-activity-with-an-iodinated-hydrogelator
#17
Zhen Zheng, Anming Tang, Yong Guan, Liang Chen, Fuqiang Wang, Peiyao Chen, Weijuan Wang, Yufeng Luo, Yangchao Tian, Gaolin Liang
Alkaline phosphatase (ALP) is an important enzyme, but direct imaging of ALP activity with high spatiotemporal resolution remains challenging. In this work, we rationally designed an iodinated hydrogelator precursor Nap-Phe-Phe(I)-Tyr(H2PO3)-OH (1P) which self-assembles into nanofibers to form hydrogel under the catalysis of ALP. With this property of concentrating iodine atoms at the locations of ALP, 1P was successfully applied for direct nanocomputed tomography (nano-CT) imaging of ALP activity in bacteria for the first time...
December 9, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27924256/operating-principles-of-rotary-molecular-motors-differences-between-f1-and-v1-motors
#18
REVIEW
Ichiro Yamato, Yoshimi Kakinuma, Takeshi Murata
Among the many types of bioenergy-transducing machineries, F- and V-ATPases are unique bio- and nano-molecular rotary motors. The rotational catalysis of F1-ATPase has been investigated in detail, and molecular mechanisms have been proposed based on the crystal structures of the complex and on extensive single-molecule rotational observations. Recently, we obtained crystal structures of bacterial V1-ATPase (A3B3 and A3B3DF complexes) in the presence and absence of nucleotides. Based on these new structures, we present a novel model for the rotational catalysis mechanism of V1-ATPase, which is different from that of F1-ATPases...
2016: Biophysics and Physicobiology
https://www.readbyqxmd.com/read/27906391/large-area-growth-of-vertically-aligned-luminescent-mos2-nanosheets
#19
G Deokar, N S Rajput, P Vancsó, F Ravaux, M Jouiad, D Vignaud, F Cecchet, J-F Colomer
Vertically aligned MoS2 nanosheets (NSs) with exposed edges were successfully synthesized over a large area (∼2 cm(2)). The NSs were grown using an ambient pressure chemical vapor deposition technique via rapid sulfurization of sputter deposited thick molybdenum films. Extensive characterization of the grown MoS2 NSs has been carried out using high resolution scanning and transmission electron microscopy (SEM & TEM). A special care was given to the TEM lamella preparation process by means of a focused ion beam to preserve the NS growth direction...
January 7, 2017: Nanoscale
https://www.readbyqxmd.com/read/27870842/probing-the-electronic-and-catalytic-properties-of-a-bimetallic-surface-with-3%C3%A2-nm-resolution
#20
Jin-Hui Zhong, Xi Jin, Lingyan Meng, Xiang Wang, Hai-Sheng Su, Zhi-Lin Yang, Christopher T Williams, Bin Ren
An atomic- and molecular-level understanding of heterogeneous catalysis is required to characterize the nature of active sites and improve the rational design of catalysts. Achieving this level of characterization requires techniques that can correlate catalytic performances to specific surface structures, so as to avoid averaging effects. Tip-enhanced Raman spectroscopy combines scanning probe microscopy with plasmon-enhanced Raman scattering and provides simultaneous topographical and chemical information at the nano/atomic scale from ambient to ultrahigh-vacuum and electrochemical environments...
November 21, 2016: Nature Nanotechnology
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