Comparison of Cobalt Based Catalysts Supported on MWCNT and SBA-15 Supporters for Fischer-Tropsch Synthesis by Using Autoclave Type Reactor

2011 ◽  
Vol 364 ◽  
pp. 70-75 ◽  
Author(s):  
Adkham Yakubov ◽  
M.G. Kutty ◽  
Pei Lee Siew ◽  
Maizatul S. Shaharun ◽  
S.B. Abd Hamid ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Multiwall Carbon Nanotubes ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Santa Barbara ◽  
X Ray ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Multiwall Carbon ◽  
Autoclave Reactor

10 and 40 wt% Co/Multiwall Carbon Nanotubes (MWCNT) and 10 and 40 wt% Co/Santa Barbara Amorphous-15 (SBA-15) catalysts were prepared via incipient wetness impregnation method. It was characterized by Scanning Electron Microscopy, BET, X-ray Diffractometry (XRD), Transmission Electron Microscopy (TEM), Temperature-Programmed Reduction and H2Desorption. A 200 ml hastelloy autoclave reactor was implemented to see the performance of the catalysts. It was observed that the performance of 40 wt% Co/SBA-15 was higher that other catalysts in terms of production of longer chain paraffins.

Stacking Faults in SiC Nanowires

2008 ◽  
Vol 8 (7) ◽  
pp. 3504-3510 ◽  
Author(s):  
K. L. Wallis ◽  
M. Wieligor ◽  
T. W. Zerda ◽  
S. Stelmakh ◽  
S. Gierlotka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stacking Faults ◽  
Multiwall Carbon Nanotubes ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Ir Spectrometry ◽  
X Ray ◽  
Sic Nanowires ◽  
Transmission Electron ◽  
Multiwall Carbon

SiC nanowires were obtained by a reaction between vapor silicon and multiwall carbon nanotubes, CNT, in vacuum at 1200 °C. Raman and IR spectrometry, X-ray diffraction and high resolution transmission electron microscopy, HRTEM, were used to characterize properties of SiC nanowires. Morphology and chemical composition of the nanowires was similar for all samples, but concentration of structural defects varied and depended on the origin of CNT. Stacking faults were characterized by HRTEM and Raman spectroscopy, and both techniques provided complementary results. Raman microscopy allowed studying structural defects inside individual nanowires. A thin layer of amorphous silicon carbide was detected on the surface of nanowires.

scholarly journals Composite Nanofibers Containing Multiwall Carbon Nanotubes as Biodegradable Membranes in Reconstructive Medicine

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 63 ◽  
Author(s):  
Andrzej Hudecki ◽  
Dorota Łyko-Morawska ◽  
Wirginia Likus ◽  
Magdalena Skonieczna ◽  
Jarosław Markowski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Maxillofacial Surgery ◽  
Multiwall Carbon Nanotubes ◽  
Dermal Fibroblasts ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Biological Responses ◽  
Transmission Electron ◽  
Multiwall Carbon

We have tested titanium (Ti) plates that are used for bone reconstruction in maxillofacial surgery, in combination with five types of novel long-resorbable biomaterials: (i) PCL0—polycaprolactone without additives, (ii) PCLMWCNT—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT), (iii) PCLOH—polycaprolactone doped with multiwall carbon nanotubes (MWCNT) containing –OH hydroxyl groups, (iv) PCLCOOH—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT) containing carboxyl groups, and (v) PCLTI—polycaprolactone with the addition of Ti nanoparticles. The structure and properties of the obtained materials have been examined with the use of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and/or X-ray powder diffraction (XRD). Titanium BR plates have been covered with: (i) PCL0 fibers (PCL0BR—connection plates), (ii) PCLMWCNT fibers (PCLMWCNTBR—plates), (iii) PCLOH fibers (PCLOHBR—plates), (iv) PCLCOOH (PCLCOOHBR—plates), (v) PCLTI fiber (PCLTIBR—connection plates). Such modified titanium plates were exposed to X-ray doses corresponding to those applied in head and neck tumor treatment. The potential leaching of toxic materials upon the irradiation of such modified titanium plates, and their effect on normal human dermal fibroblasts (NHDF) have been assessed by MTT assay. The presented results show variable biological responses depending on the modifications to titanium plates.

scholarly journals Tungsten Oxide-Modified SSZ-13 Zeolite as an Efficient Catalyst for Ethylene-To-Propylene Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 553
Author(s):  
Mansurbek Urol ugli Abdullaev ◽  
Sungjune Lee ◽  
Tae-Wan Kim ◽  
Chul-Ung Kim
Keyword(s):  
Tungsten Oxide ◽  
Fixed Bed ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
X Ray ◽  
Propylene Selectivity ◽  
Temperature Programmed

Among the zeolitic catalysts for the ethylene-to-propylene (ETP) reaction, the SSZ-13 zeolite shows the highest catalytic activity based on both its suitable pore architecture and tunable acidity. In this study, in order to improve the propylene selectivity further, the surface of the SSZ-13 zeolite was modified with various amounts of tungsten oxide ranging from 1 wt% to 15 wt% via a simple incipient wetness impregnation method. The prepared catalysts were characterized with several analysis techniques, specifically, powder X-ray diffraction (PXRD), Raman spectroscopy, temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of ammonia (NH3-TPD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and N2 sorption, and their catalytic activities were investigated in a fixed-bed reactor system. The tungsten oxide-modified SSZ-13 catalysts demonstrated significantly improved propylene selectivity and yield compared to the parent H-SSZ-13 catalyst. For the tungsten oxide loading, 10 wt% loading showed the highest propylene yield of 64.9 wt%, which was 6.5 wt% higher than the pristine H-SSZ-13 catalyst. This can be related to not only the milder and decreased strong acid sites but also the diffusion restriction of bulky byproducts, as supported by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) observation.

scholarly journals Pure Acetylene Semihydrogenation over Ni–Cu Bimetallic Catalysts: Effect of the Cu/Ni Ratio on Catalytic Performance

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 509 ◽  
Author(s):  
Shuzhen Zhou ◽  
Lihua Kang ◽  
Xuening Zhou ◽  
Zhu Xu ◽  
Mingyuan Zhu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bimetallic Catalysts ◽  
Density Functional ◽  
Calcium Carbide ◽  
Raw Material ◽  
Impregnation Method ◽  
X Ray ◽  
Transmission Electron ◽  
Ethylene Selectivity

Ethylene is an important chemical raw material and with the increasing consumption of petroleum resources, the production of ethylene through the calcium carbide acetylene route has important research significance. In this work, a series of bimetallic catalysts with different Cu/Ni molar ratios are prepared by co-impregnation method for the hydrogenation of calcium carbide acetylene to ethylene. The introduction of an appropriate amount of Cu effectively inhibits not only the formation of ethane and green oil, thus increasing the selectivity of ethylene, but also the formation of carbon deposits, which improves the stability of the catalyst. The ethylene selectivity of the Ni–Cu bimetallic catalyst increases from 45% to 63% compared with the Ni monometallic counterpart and the acetylene conversion still can reach 100% at the optimal conditions of 250 °C, 8000 mL·g−1·h−1 and V(H2)/V(C2H2) = 3. X-ray diffraction and transmission electron microscopy confirmed that the metal particles were highly dispersed on the support, High-resolution transmission electron microscopy and H2-Temperature programmed reduction proved that there was an interaction between Ni and Cu, combined with X-ray photoelectron spectroscopy and density functional theory calculations results, Cu transferred electrons to Ni changed the Ni electron cloud density in NiCux catalysts, thus reducing the adsorption of acetylene and ethylene, which is favorable to ethylene selectivity.

Synthesis and Characterization of Carbon Nanotubes from Palm Oil by Aerosol-Assisted CVD

2013 ◽  
Vol 667 ◽  
pp. 218-223
Author(s):  
M. Maryam ◽  
A.B. Suriani ◽  
M.S. Shamsudin ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Palm Oil ◽  
Deposition Temperature ◽  
Multiwall Carbon Nanotubes ◽  
Single Wall Carbon Nanotubes ◽  
X Ray ◽  
Weight Percentage ◽  
Transmission Electron ◽  
Reaction Furnace

This paper will report on the synthesis of bundles of aligned single wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs) from palm oil precursor and ferrocene as catalyst source by two stage aerosol-assisted CVD system at various deposition temperature ranging from 700-900oC. Palm oil was pyrolised into the furnace which contained the catalyst source producing black substances at the wall of the reaction furnace which were then collected to be characterized. Field emission scanning electron microscopy equipped with energy dispersive X-ray was used to obtain weight percentage, identification of samples and image of CNTs which showed different structures and diameters of CNTs relative to the deposition temperature of furnace. Raman Spectroscopy was used to further study the quality and identification of samples and finally X-ray powder diffraction was used to determine the crystalinity of samples. Individual micrograph of MWNTs at optimized deposition temperature was also obtained from the high resolution transmission electron microscopy.

scholarly journals Heterogeneous Fenton-like oxidation of p-hydroxybenzoic acid using Fe/CeO2-TiO2 catalyst

2019 ◽  
Vol 79 (7) ◽  
pp. 1276-1286 ◽  
Author(s):  
Tijani Hammedi ◽  
Mohamed Triki ◽  
Mayra G. Alvarez ◽  
Jordi Llorca ◽  
Abdelhamid Ghorbel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Molar Ratio ◽  
Hydroxybenzoic Acid ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Temperature Programmed

Abstract This paper is built on the Fenton-like oxidation of p-hydroxybenzoic acid (p–HBZ) in the presence of H2O2 and 3%Fe supported on CeO2-TiO2 aerogels under mild conditions. These catalysts were deeply characterized by X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The effect of thermal treatment, pH (2–3, 5, 7), H2O2/p–HBZ molar ratio (5, 15, 20, 25) and reaction temperature (25 °C, 40 °C and 60 °C) on the catalytic properties of supported Fe catalysts are studied. Our results highlight the role of CeO2 and the calcination of the catalyst to obtain the highest catalytic properties after 10 min: 73% of p–HBZ conversion and 52% of total organic carbon (TOC) abatement.

scholarly journals Effect of Carboxylic Functional Group Functionalized on Carbon Nanotubes Surface on the Removal of Lead from Water

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Muataz Ali Atieh ◽  
Omer Yehya Bakather ◽  
Bassam Al-Tawbini ◽  
Alaadin A. Bukhari ◽  
Faraj Ahmad Abuilaiwi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Functional Group ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Properties ◽  
Average Diameter ◽  
Transmission Electron ◽  
Physical And Chemical ◽  
Multiwall Carbon ◽  
Carboxylic Functional Group

The adsorption mechanism of the removal of lead from water by using carboxylic functional group (COOH) functionalized on the surface of carbon nanotubes was investigated. Four independent variables including pH, CNTs dosage, contact time, and agitation speed were carried out to determine the influence of these parameters on the adsorption capacity of the lead from water. The morphology of the synthesized multiwall carbon nanotubes (MWCNTs) was characterized by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) in order to measure the diameter and the length of the CNTs. The diameters of the carbon nanotubes were varied from 20 to 40 nm with average diameter at 24 nm and 10 micrometer in length. Results of the study showed that 100% of lead was removed by using COOH-MCNTs at pH 7, 150 rpm, and 2 hours. These high removal efficiencies were likely attributed to the strong affinity of lead to the physical and chemical properties of the CNTs. The adsorption isotherms plots were well fitted with experimental data.

Effect of Crystallization on the Catalytic Cracking Performance of Zeolite Socony Mobil-5

2018 ◽  
Vol 18 (12) ◽  
pp. 8437-8446
Author(s):  
Maojiong Cao ◽  
Youyong Su ◽  
Bing Xue ◽  
Yuxiang Yang ◽  
Xiangnong Liu
Keyword(s):  
Electron Microscopy ◽  
Crystallization Temperature ◽  
Catalytic Cracking ◽  
Acid Value ◽  
Temperature Programmed Desorption ◽  
Crystallization Time ◽  
X Ray ◽  
Transmission Electron ◽  
Cracking Performance ◽  
Temperature Programmed

In the research, zeolite socony mobil-5 (ZSM-5) catalyst was prepared by hydrothermal method and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), NH3-temperature programmed desorption (NH3-TPD) and Brunauer- Emmett-Teller (BET). The catalytic products from Jatropha carcass L. oil were analyzed by gas chromatography-mass spectrometer (GC-MS). The effects of crystallization time and crystallization temperature on catalytic cracking performance of ZSM-5 were investigated. According to the results, the catalytic cracking performance of ZSM-5 was closely associated with its pore structure. When the crystallization time was 60 h and the crystallization temperature was 170 °C, ZSM-5 with optimal catalytic cracking performance was synthesized. Catalyzed by the optimal ZSM-5, Jatropha carcass L. oil showed the liquid conversion rate of 26.60% and the acid value of 1.24 mg KOH·g−1. The main catalytic products from Jatropha carcass L. oil included benzene (10.02%), methylbenzene (20.52%), o-xylene (14.45%) and p-xylene (6.59%).

Microstructural of Cr/MWCNT Composites and its Catalysis in Synthesis of Biodiesel

2012 ◽  
Vol 455-456 ◽  
pp. 1053-1059
Author(s):  
Xue Hai Fan ◽  
Guo Min Xiao
Keyword(s):  
Electron Microscopy ◽  
Potassium Dichromate ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs), potassium dichromate (K2Cr2O7) and sulphuric acid were used for the preparation of Cr/MWCNT composite by impregnation method. The composites were comprehensively characterized by transmission electron microscopy （TEM），energy dispersive X-ray analysis (EDX), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermal gravity analysis (TGA). Due to its unique electrical and structural properties, this composite was applied to the synthesis of biodiesel (FAME) as a catalyst, showing effectively catalytic performance.

scholarly journals Influence of Nickel Loading on Reduced Graphene Oxide-Based Nickel Catalysts for the Hydrogenation of Carbon Dioxide to Methane

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 471
Author(s):  
Nur Diyan Mohd Ridzuan ◽  
Maizatul Shima Shaharun ◽  
Kah Mun Lee ◽  
Israf Ud Din ◽  
Poppy Puspitasari
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Surface ◽  
Nickel Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Co2 Methanation ◽  
X Ray ◽  
Reduced Graphene ◽  
Temperature Programmed

In this study, a series of novel nickel catalysts supported on reduced graphene oxide nanosheets (Ni/rGO) with Ni loadings of 10, 15 and 20 wt% were successfully synthesized via the incipient wetness impregnation method. The physicochemical properties of the catalysts and rGO support were thoroughly characterized by thermogravimetric analyser, X-ray diffraction, fourier-transform infrared spectroscopy, Raman spectroscopy, N2 adsorption-desorption, temperature programmed reduction, temperature programmed CO2 desorption and field emission scanning electron microscopy with energy dispersive X-ray spectroscopy. The properties of the catalysts are correlated to its catalytic activity for CO2 methanation which were investigated using three-phase slurry reactor at low temperature and pressure of 240 °C and 10 bar, respectively. Among the three catalysts of different Ni loading, Ni15/rGO shows the highest activity of 51% conversion of CO2 with total selectivity towards CH4. N2-physisorption and CO2-TPD analysis suggest that high catalytic performance of Ni15/rGO is attributed to the high surface area, strong basic sites and special support effect of rGO in anchoring the active metal.

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