Laboratory astrochemistry: catalytic reactions of organic molecules over olivine-type silicates and SiC

2017 ◽  
Vol 13 (S332) ◽  
pp. 320-325
Author(s):  
Qian Li ◽  
B. S. Liu ◽  
P. J. Sarre ◽  
A. S-C. Cheung
Keyword(s):  
Carbon Nanostructures ◽  
Organic Molecules ◽  
Thermo Gravimetric Analysis ◽  
Catalytic Reactions ◽  
Gravimetric Analysis ◽  
Transmission Electron ◽  
Similar Chemical ◽  
Polycyclic Aromatic ◽  
Co Disproportionation ◽  
Methanol To Hydrocarbon

AbstractA series of catalytic reactions has been performed in our laboratory using olivine-type silicates (OTS) and SiC as catalysts for the conversion of carbon-containing molecules (such as acetylene, CO and methanol) to small organic molecules (C2H4, C3H3, CH3O) and also polycyclic aromatic hydrocarbons (PAHs). Experimentally, small-to-medium-sized gas-phase compounds such as PAHs, reaction intermediates and hydrocarbon compounds were detected in situ using the time-of-light mass-spectrometry technique. Solid deposition on the catalyst surface was examined by high-resolution transmission electron microscopy and thermo-gravimetric analysis techniques. Our laboratory results show that the conversion of acetylene to PAHs, the CO disproportionation reaction for producing CO2 and carbon deposition (graphitic and carbon nanostructures), and also the transformation of methanol to hydrocarbon compounds can easily be achieved with OTS as a catalyst. Furthermore, the conversion of acetylene to PAHs could also be achieved by SiC as the catalyst. It is proposed that these catalytic reactions mimic similar chemical processes in circumstellar envelopes (CSEs).

Preparation and Characterization of Ultrafine Monodisperse Iron Oxide Nanoparticles by Solvothermal Method

2015 ◽  
Vol 748 ◽  
pp. 93-96
Author(s):  
Cheng Mei Liu ◽  
Yu Xia Zhao ◽  
Jin Dong ◽  
Lu Hai Li ◽  
Yen Wei ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Solvothermal Method ◽  
Physical Property Measurement System ◽  
Thermo Gravimetric Analysis ◽  
Physical Property ◽  
Oxide Nanoparticles ◽  
Gravimetric Analysis ◽  
Transmission Electron ◽  
Different Diameters

Using iron-oleate complex as a precursor, oleic acid as a stabilizer and 1-octadecene as a reductant, uniform-sized and highly monodisperse iron oxide nanoparitcles with different diameters were successfully synthesized via solvothermal method by changing reaction time. Transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), physical property measurement system (PPMS) and dynamic light scattering (DLS) was used to characterize obtained iron oxide nanoparticles. These results indicated that iron oxide nanoparitcles with the diameter ranging from 4 to 8 nm can be controllably synthesized.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

Biosynthesis and Characterization of Copper Nanoparticles Using a Bioflocculant Extracted from Alcaligenis faecalis HCB2

2019 ◽  
Vol 11 (11) ◽  
pp. 1064-1070 ◽  
Author(s):  
Nkosinathi G. Dlamini ◽  
Albertus K. Basson ◽  
V. S. R. Rajasekhar Pullabhotla
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Copper Nanoparticles ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir

Bioflocculant from Alcaligenis faecalis HCB2 was used in the eco-friendly synthesis of the copper nanoparticles. Nanoparticles were characterized using a scanning electron microscope (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy, thermo gravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). The transmission electron microscopy images showed close to spherical shapes with an average particle size of ∼53 nm. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of the Cu nanopartilces and also the other elements such as O, C, P, Ca, Cl, Na, K, Mg, and S originated from the bioflocculant. FT-IR results showed the presence of the –OH and –NH2 groups, aliphatic bonds, amide and Cu–O bonds. Powder X-ray diffraction peaks confirmed the presence of (111) and (220) planes of fcc structure at 2 of 33° and 47° respectively with no other impurity peaks.

Carbon Nanostructures Produced by Liquid Phase Exfoliation of Graphite in the Presence of Small Organic Molecules

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Jesús I. Tapia ◽  
Mildred Quintana
Keyword(s):  
Liquid Phase ◽  
Small Molecules ◽  
Carbon Nanostructures ◽  
Organic Molecules ◽  
Chemical Nature ◽  
Spectroscopy Analysis ◽  
Small Organic Molecules ◽  
Transmission Electron ◽  
Secondary Reactions ◽  
Carbon Nanoscrolls

AbstractWe report on the formation of different carbon nanostructures by ultrasonication of graphite in DMF upon the addition of 3 different small molecules: ferrocene carboxylic acid, dimethylamino methyl-ferrocene, and benzyl aldehyde. Our results confirm that acoustic cavitation in organic solvents generates free radicals which enable or are involved in secondary reactions. During the ultrasonication process, the addition of small molecules induces the formation of different carbon nanostructures mainly depending on the chemical nature of the molecule, as observed by transmission electron microscopy (TEM). Raman spectroscopy analysis confirms that small molecules act as radical scavengers reducing the damage caused by cavitation to graphene sheets producing long nanoribbons, squared sheets, or carbon nanoscrolls. Importantly, this strategy allows the production of different carbon nanostructures in liquid-phase making them readily available for their chemical functionalization or for their incorporation into hybrids materials enabling the development of new advanced biological applications.

scholarly journals Synthesis of zirconia-based solid acid nanoparticles for fuel cell application

2016 ◽  
Vol 27 (2) ◽  
pp. 60 ◽  
Author(s):  
Rudzani A Sigwadi ◽  
Sipho E Mavundla ◽  
Nosipho Moloto ◽  
Touhami Mokrani
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Acid Sites ◽  
Precipitation Method ◽  
Zro2 Nanoparticles ◽  
Gravimetric Analysis ◽  
Ambient Temperatures ◽  
Fuel Cell Application ◽  
Transmission Electron ◽  
Zirconia Nanoparticles

Zirconia nanoparticles were prepared by the precipitation and ageing methods. The precipitation method was performed by adding ammonium solution to the aqueous solution of zirconium chloride at room temperature. The ageing method was performed by leaving the precipitate formed in the mother liquor in the glass beaker for 48 hours at ambient temperatures. The nanoparticles from both methods were further sulphated and phosphated to increase their acid sites. The materials prepared were characterised by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Brunauer-EmmettTeller (BET), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The XRD results showed that the nanoparticles prepared by the precipitation method contained mixed phases of tetragonal and monoclinic phases, whereas the nanoparticles prepared by ageing method had only tetragonal phase. The TEM results showed that phosphated and sulphated zirconia nanoparticles obtained from the ageing method had a smaller particle size (10–12 nm) than the nanoparticles of approximately 25–30 nm prepared by precipitation only. The BET results showed that the ZrO2 nanoparticles surface area increased from 32 to 72 m2/g when aged.

Electrochemical Performance of LiFePO4 Coated by Nano-Polyaniline Coater for Lithium-Ion Batteries

2010 ◽  
Vol 146-147 ◽  
pp. 551-555
Author(s):  
Wen Qiang Gong ◽  
Yi Feng Chen ◽  
Bing Sun ◽  
Han Chen
Keyword(s):  
In Situ Polymerization ◽  
Thermo Gravimetric Analysis ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Stability ◽  
Gravimetric Analysis ◽  
Capacity Loss ◽  
Transmission Electron ◽  
Polyaniline Composites

Aniline was polymerized on the surface of LiFePO4 particles by in-situ polymerization technique, forming LiFePO4/polyaniline composites. The composites were characterized by Thermo gravimetric analysis, specific surface area tests, high resolution transmission electron microscopy observation. The specific capacity, rate capability and cycling stability of composites were studied by charge-discharge tests. The experimental results show that the LiFePO4/polyaniline composite containing 6.75% polyaniline possesses the best electrochemical properties. Its initial capacity reaches 151.97 mAh.g-1 at C/10 rate, its cycling stability is excellent, its specific capacity is 124.89 mAh.g-1 at 1 C rate, its capacity loss is only 17.82% when rate increased from C/10 to 1 C.

Synthesis of Carbon Nanostructures and CaCO3 Nanoparticles by Arc Discharge in Mineral Water

2011 ◽  
Vol 15 ◽  
pp. 57-67 ◽  
Author(s):  
V. Eskizeybek ◽  
E.S. Karabulut ◽  
A. Avci
Keyword(s):  
Electron Microscopy ◽  
Production Rate ◽  
Carbon Nanostructures ◽  
Mineral Water ◽  
Arc Discharge ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Caco3 Nanoparticles ◽  
Multi Walled Carbon Nanotubes ◽  
Arc Current

The synthesis of multi-walled carbon nanotubes MWCNTs, carbon nanoshells, carbon nanoonions (CNOs), different types of carbon nanostructures and CaCO3 nanoparticles were performed using an arc-discharge method in mineral water. The structures of the synthesized nanostructures were visualized by scanning electron microscopy and transmission electron microscopy (TEM). Furthermore, ultraviolet-visible spectroscopy and thermo-gravimetric analysis (TGA) were used to determine the optical and thermal properties of the synthesized nanostructures. The TEM observations revealed that as-synthesized MWCNTs and CNOs have nominal diameters in the range of 10-20 nm and 30-50 nm, respectively. The CaCO3 nanoparticles were directly synthesized using arc discharge due to the presence of Ca minerals in the mineral water. The production rate of synthesized MWCNTs decreased when the arc current increased above 50 A, and the production rate of different nanoparticles increased with increasing arc current. The thermal-oxidative stability of the carbon nanostructures using TGA was explored separately under argon and oxygen atmospheres.

Characterisation of Hydroxyapatite/Bacterial Cellulose Nanocomposites

2009 ◽  
Vol 17 (6) ◽  
pp. 353-358 ◽  
Author(s):  
Shengnan Zhang ◽  
Guangyao Xiong ◽  
Fang He ◽  
Yuan Huang ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bacterial Cellulose ◽  
Photoelectron Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Cellulose Nanocomposites

A novel nanocomposite material consisting of hydroxyapatite (HAp) deposited on a phosphorylated bacterial cellulose (BC) has been synthesised via a biomimetic route. X-ray photoelectron spectroscopy (XPS) showed that phosphate groups were successfully introduced to the hydroxyl groups of BC by phosphorylation reaction to promote the growth of calcium phosphate. Transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) patterns of HAp/BC demonstrated that HAp crystals wrap the surfaces of BC fibres. In this work, HAp/BC nanocomposites were studied using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA result suggested that HAp/BC nanocomposite, similar to natural bone in terms of composition, contained carbonate ions, in agreement with our previous Fourier transform infrared (FTIR) spectroscopy results. Thermal behaviour differences between BC and HAp/BC were observed by differential scanning calorimetry (DSC). The thermal stability of HAp/BC obtained from DSC showed an improvement when compared to that of a pure BC sample.

Synthesis, characterization of visible active MO hallow spheres by combustion technique

2018 ◽  
Vol 1 (3) ◽  
pp. 1-14
Author(s):  
G Thennarasu ◽  
A Sivasamy
Keyword(s):  
Electron Microscope ◽  
Diffuse Reflectance Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Oxygen Demand ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Transmission Electron ◽  
Direct Blue ◽  
Combustion Technique

A simple method to synthesize nano-sized hallow sphere such as Zn-Ce metal oxide (MO) by combustion technique. The product was characterized by X-ray diffraction (XRD), Field emission-scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), Thermo gravimetric analysis (TGA), Diffuse Reflectance Spectroscopy (DRS) and Transmission electron microscope (TEM). The photocatalytic activity of Zn-Ce MO nano-sized hallow sphere was examined by studying the degradation of direct blue 71 (DB71) under visible light irradiations in a slurry photoreactor. The effect of parameters such as the catalyst dosage, concentration of the dye, pH and kinetics on photocatalytic degradation of DB71 is also studied. Degradation of dye was confirmed by UV-VIS spectrum, chemical oxygen demand (COD) and ESI-Mass.

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