scholarly journals Catalytic Activity of Hybrid Iron Oxide Silver Nanoparticles in Methyl Methacrylate Polymerization

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 422
Author(s):  
Sanaa M. Solyman ◽  
Mohamed S.A. Darwish ◽  
Jungwon Yoon
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Iron Oxide ◽  
Methyl Methacrylate ◽  
Room Temperature ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Catalytic Systems ◽  
X Ray

One of the challenges in the preparation of poly(methyl methacrylate) (PMMA) is to develop new catalytic systems with improved efficiency. A hybrid iron oxide silver catalyst holds promise in solving this issue. Catalysts were prepared at room temperature by a two-step technique. First, iron oxide nanoparticles were prepared by the reduction of FeCl3 using sodium borohydride (NaBH4) at room temperature. Second, magnetic nanoparticles doped with a series of Ag nanoparticles (Ag, Ag/3 –amino propyltriethoxysilane (APTES) and Ag/poly(ethyleneimine) (PEI)). The prepared catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and Fourier-transform infrared spectroscopy (FTIR). The catalytic activity of Fe, Ag/Fe, PEI–Ag/Fe, and APTES–Ag/Fe in methyl methacrylate (MMA) polymerization was investigated in the presence of O2, N2, NaHSO3, and benzoyl peroxide in bulk or solution conditions. The produced polymer was characterized by gel permeation chromatography (GPC) and proton nuclear magnetic resonance spectroscopy (1HNMR). The structures of PEI–Ag/Fe and APTES–Ag/Fe are assumed. The conversion efficiency was 100%, 100%, 97.6%, and 99.1% using Fe, Ag/Fe, PEI–Ag/Fe, and APTES–Ag/Fe catalysts at the optimum conditions, respectively. Hybrid iron oxide silver nanoparticles are promising catalysts for PMMA preparation.

Hollow structured CoSn(OH)6-supported Pt for effective room-temperature oxidation of gaseous formaldehyde

2016 ◽  
Vol 09 (06) ◽  
pp. 1642009 ◽  
Author(s):  
Jing Zhou ◽  
Yong Zhao ◽  
Lifan Qin ◽  
Chen Zeng ◽  
Wei Xiao
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Room Temperature ◽  
Synergetic Effect ◽  
Hollow Structure ◽  
Pt Nanoparticles ◽  
Hydroxyl Groups ◽  
High Catalytic Activity ◽  
Temperature Oxidation ◽  
X Ray

Uniform CoSn(OH)6 hollow nanoboxes and the derivative with Pt loading (Pt/CoSn(OH)6) were herein synthesized and characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM and TEM analyses showed that CoSn(OH)6 possessed mesoporous hollow structure and Pt nanoparticles with size of 2–8[Formula: see text]nm were uniformly dispersed on the surface of CoSn(OH)6 nanoboxes. The performances of the catalysts for the formaldehyde (HCHO) removal at room temperature were evaluated. These Pt/CoSn(OH)6 catalysts exhibited a remarkable catalytic activity as well as stability for room-temperature oxidative decomposition of gaseous HCHO, while the corresponding CoSn(OH)6 only showed adsorption. The synergetic effect between the highly dispersed Pt nanoparticles and the CoSn(OH)6 nanoboxes with mesoporous hollow structure, a large surface area and abundant surface hydroxyl groups is considered to be the main reason for the observed high catalytic activity of Pt/CoSn(OH)6.

scholarly journals Citrus Extract Modified Graphene Oxide as a Green and Heterogeneous Organocatalyst for the Synthesis of Imidazole Derivatives

2020 ◽  
Vol 32 (9) ◽  
pp. 2375-2380
Author(s):  
S. ARUNKUMAR ◽  
S. CHIDAMBARA VINAYAGAM ◽  
S. LAKSHMANAN ◽  
S. ARUL ANTONY
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Room Temperature ◽  
Fourier Transforms ◽  
X Ray ◽  
Imidazole Derivatives ◽  
Modified Graphene Oxide ◽  
Citrus Extract ◽  
Microscopy Images

A naturally benign convention was created with a surface change of graphene oxide by citrus extract as catalyst was prepared by a straight-forward chemical modification method. The prepared catalyst′s catalytic activity was examined by the synthesis of imidazole derivatives at room temperature. It shows a strong acidic catalytic and sustainable organocatalyst. The prepared catalyst was characterized using different analytical procedures like elemental analysis, Fourier transforms infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), energy-dispersive X-ray analysis (EDS), scanning electron microscopy images (SEM) and transmission electron microscopy images (TEM) analysis. The catalytic activity shows high activity and can be reused without significant loss of catalytic activity after five times. A present catalyst works easily under room temperature.

scholarly journals BIOSYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM MANGROVE BARK – RHIZOPHORA MUCRONATA EXTRACT

2020 ◽  
pp. 91-94
Author(s):  
AJI JOVITHA AT ◽  
DEIVASIGAMANI B
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
High Resolution ◽  
Room Temperature ◽  
Energy Dispersive ◽  
Rhizophora Mucronata ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Objective: The present study attempted to synthesize AgNPs from mangrove bark Rhizophora mucronata and analyze characteristics. The synthesized AgNPs analyzed with UV–vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) for confirming the nanoparticles. Methods: The dried R. mucronata bark was powdered and kept in at 55°C for 15 min in a water bath and cooled at room temperature to get the extract. The R. mucronata bark extract was treated with silver nitrate and kept overnight in the dark environment which will turn the solution to dark brown color. The silver nanoparticles were characterized using UV–visible absorption at room temperature. Further characterization was also done with X-ray diffraction, high-resolution transmission electron microscope measurements, and DLS analysis. Results: The synthesized AgNPs were analyzed with various analytical methods that revealed the abundant presence of silver nanoparticles. The UV–vis spectroscopy analysis exposed the surface plasmon resonance peak of 422 nm. High-resolution transmission electron microscopy (HRTEM) analysis indicated the size ranging from 10 nm to 200 nm in diameter and a spherical shaped poly dispersal of the particles. The energy-dispersive X-ray (EDX) and DLS also confirmed the presence of silver atoms. Conclusion: Silver nanoparticles of Rhizophora mucronata bark revealed a well-defined structure and may be used in antimicrobial function in further researches.

scholarly journals STUDY ON CATALYTIC ACTIVITY OF TIO2/SIO2, IN THE OXIDATION OF STYRENE

2009 ◽  
Vol 12 (3) ◽  
pp. 77-84
Author(s):  
Thao Tien Nguyen ◽  
Ngoan Thi Nguyen ◽  
Long Van Dang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Catalytic Activity ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Scanning Electron

All TiO2/SiO2 samples were prepared by the impregnation of Ti(i-PrO)4 in isopropanol at room temperature followed drying and calcination. The solids were characterized by several techniques including X- ray diffraction (XRD), IR spectroscopy, Scanning Electron Microscopy (SEM). No reflection lines of TiO2 are detected at a low content of TiO2 (< 7%), but are more visible at a higher concentration. The catalysts are tested in the liquid oxidation of styrene under mild conditions, producing mainly benzaldehyde. The effects of variables on the catalytic activity are also investigated.

Preparation and Photocatalytic Properties of Bi2WO6 with Different Morphologies

2013 ◽  
Vol 779-780 ◽  
pp. 390-393
Author(s):  
Ying Chen ◽  
Xu Wang ◽  
Hua Song ◽  
Hua Lin Song
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photocatalytic Activity ◽  
Catalytic Activity ◽  
Room Temperature ◽  
Great Influence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphology And Structure ◽  
Scanning Electron

Bismuth tungstate (Bi2WO6) microcrystalline with different surfactant were successfully prepared by a facile hydrothermal route.The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and BrunauerEmmettTeller surface area (BTE) in detail. The photocatalytic activity of the samples was also evaluated using the degradation of Rh B at room temperature under visible light irradiation. It was found that the surfactant played important roles in the formation process of controlling the morphology and structure of the catalyst and also had a great influence on the catalytic activity. SDS and CTAB effectively improved the catalytic activity and PVP was good at controlling morphologies.

scholarly journals Biosynthesis of Silver Nanoparticles UsingKedrostis foetidissima (Jacq.) Cogn.

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
M. Amutha ◽  
P. Lalitha ◽  
M. Jannathul Firdhouse
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Room Temperature ◽  
Ftir Analysis ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Higher Temperature ◽  
Uv Visible ◽  
Scanning Electron

Nanosilver was synthesized using the aqueous solution of solvent extracts of leaf and stem ofKedrostis foetidissima. Three different methods of formation of silver nanoparticles such as reaction at (i) room temperature, (ii) higher temperature, and (iii) sonication were employed in the present study. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, X-ray diffractometer, Scherrer’s formula, scanning electron microscopy, and FTIR analysis.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Synthesis, structural characterization and catalytic activity of chlororuthenium(II) complexes with substituted Schiff base/phosphine ancillary ligands

2020 ◽  
Vol 75 (9-10) ◽  
pp. 851-857
Author(s):  
Chong Chen ◽  
Fule Wu ◽  
Jiao Ji ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Structural Characterization ◽  
Room Temperature ◽  
Molecular Structures ◽  
Cationic Complex ◽  
Neutral Complex ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography

AbstractTreatment of [(η6-p-cymene)RuCl2]2 with one equivalent of chlorodiphenylphosphine in tetrahydrofuran at reflux afforded a neutral complex [(η6-p-cymene)RuCl2(κ1-P-PPh2OH)] (1). Similarly, the reaction of [Ru(bpy)2Cl2·2H2O] (bpy = 2,2′-bipyridine) and chlorodiphenylphosphine in methanol gave a cationic complex [Ru(bpy)2Cl(κ1-P-PPh2OCH3)](PF6) (2), while treatment of [RuCl2(PPh3)3] with [2-(C5H4N)CH=N(CH2)2N(CH3)2] (L1) in tetrahydrofuran at room temperature afforded a ruthenium(II) complex [Ru(PPh3)Cl2(κ3-N,N,N-L1)] (3). Interaction of the chloro-bridged complex [Ru(CO)2Cl2]n with one equivalent of [Ph2P(o-C6H4)CH=N(CH2)2N(CH3)2] (L2) led to the isolation of [Ru(CO)Cl2(κ3-P,N,N-L2)] (4). The molecular structures of the ruthenium(II) complexes 1–4 have been determined by single-crystal X-ray crystallography. The properties of the ruthenium(II) complex 4 as a hydrogenation catalyst for acetophenone were also tested.

scholarly journals Characterization and Antibacterial Response of Silver Nanoparticles Biosynthesized Using an Ethanolic Extract of Coccinia indica Leaves

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Suresh V. Chinni ◽  
Subash C. B. Gopinath ◽  
Periasamy Anbu ◽  
Neeraj Kumar Fuloria ◽  
Shivkanya Fuloria ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Zeta Potential ◽  
Ethanolic Extract ◽  
Spherical Shape ◽  
Bacterial Strains ◽  
X Ray ◽  
Coccinia Indica ◽  
Antibacterial Potential

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.

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