Fabrication and Characterization of Hollow Zirconia Microspheres Using Calcium Carbonate as Template

2016 ◽  
Vol 230 (11) ◽  
Author(s):  
Shengsong Ge ◽  
Weixue Zhu ◽  
Qian Shao

AbstractStabilized spherical hollow zirconia was fabricated using calcium carbonate as template through a simple precipitation method. The as-prepared products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption–desorption isotherms (BET). Adsorption performance of the as-prepared products toward Congo red (CR) aqueous solutions was tested and discussed. Results show that the prepared hollow ZrO

2013 ◽  
Vol 22 (3) ◽  
pp. 096369351302200
Author(s):  
N. Ivashchenko ◽  
V. Tertykh ◽  
J. Skubiszewska-Zięba ◽  
R. Leboda ◽  
S. Khainakov ◽  
...  

Palladium nanoparticles with controlled size were synthesized within the pores of the mesoporous SBA-15 and SBA-16 silicas with grafted silicon hydride groups. Nitrogen adsorption-desorption method, X-ray diffraction and transmission electron microscopy (TEM) were used for characterization of palladium-containing composites. Results of material study clearly revealed that Pd nanoparticles prepared by this method were located inside the porous channels and were quite uniform in size (mostly 5–6 nm). The influence of metal content on the particles size and porous structure of supports was investigated.


2017 ◽  
Vol 373 ◽  
pp. 299-302
Author(s):  
Bo Zhou ◽  
Chong Yang Li ◽  
Ning Qi ◽  
Zhi Quan Chen

Porous ZnO were synthesized with soft template method using zinc acetate Zn (CH3COO)2·2H2O as precursor and block copolymer F127 as the surfactant. Nitrogen adsorption-desorption measurements indicate that the ZnO sample contains large pores with mean diameter of about 30 nm. However, both small-angle X-ray diffraction and transmission electron microscope measurements indicate that the pore ordering is missing. Positron lifetime measurements reveal two long lifetime components in the porous ZnO. The longest lifetime τ4 (75 ns) corresponds to ortho-positronium (o-Ps) annihilation in large pores. The pore size estimated from τ4 is about 10.6 nm. This is much smaller than that estimated from Nitrogen adsorption-desorption measurements. In addition, the intensity I4 is only about 2.2%. This is probably due to the chemical quenching and/or inhibition of positronium formation induced by ZnO, which reduces o-Ps lifetime and intensity, and leads to under estimation of the pore size.


2013 ◽  
Vol 779-780 ◽  
pp. 201-204
Author(s):  
Miao Li ◽  
Hong Wang ◽  
Xian Qing Li ◽  
Jin Rong Liu

Ordered hexagonally mesoporous molecular sieve Al-MCM-41 with Si/Al (atom) ratio=9 was prepared by hydrothermal synthesis using raw kaolin. X-ray diffraction (XRD), Nitrogen adsorption desorption, Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Detector (EDX) were employed to characterise raw kaolin, calcined kaolin, as-synthesized and calcined Al-MCM-41. The results indicated that characteristic reflections of raw kaolin disappeared after calcination, both of as-synthesized and calcined Al-MCM-41 exhibited well ordered hexagonally mesoporous molecular sieve structure.


NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.


2014 ◽  
Vol 805 ◽  
pp. 678-683
Author(s):  
Ângela da Costa Nogueira ◽  
Jocielys Jovelino Rodrigues ◽  
Liliane Andrade Lima ◽  
Meiry Glaúcia Freire Rodrigues

In this study catalysts Fe/SBA-15 were prepared for Fischer-Tropsch Synthesis. SBA-15 samples were synthesized under acidic conditions using triblock copolymer Pluronic as a template and tetraethyl orthosilicate as a silica source.The molar composition was: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O. Fe/SBA-15 catalysts with different iron loading (15 wt. % and 20 wt. %) were prepared by wetness impregnation of relative SBA-15 with the desired amount of aqueous iron nitrate. The obtained catalyst were characterized by X ray diffraction (XDR), nitrogen adsorption-desorption and energy dispersive X-ray spectrometry (EDX). After impregnation of Fe the XRD profiles were almost unchanged and exhibited the high diffraction peaks of SBA-15 at low angles. The analysis of nitrogen adsorption-desorption was observed that the values of specific surface area decreased as the concentration of metal impregnated increased. And by the EDX analysis verified that the iron contents obtained are close to nominal levels of iron.


2016 ◽  
Vol 25 (6) ◽  
pp. 096369351602500 ◽  
Author(s):  
Ruimin Fu ◽  
Mingfu Zhu

Nowadays, the hummers method for preparation of graphene oxide (GO) was improved. The grapheme oxide @ Fe3O4 magnetic nanocomposites were synthesized by co-precipitation method. After analysing the morphology and structure of obtained nanocomposites by X-ray diffraction (XRD), transmission electron microscope (TEM) and Fourier transform infrared (FT-IR) spectroscopy, the result was shown as follows. The particle size of Fe3O4 in nanocomposites is 30 nm. Many functional groups are found in grapheme oxide, and such groups could be used to bind with the drug. In the test for magnetic properties, the nanocomposites gathered rapidly in the vicinity of the permanent magnet. The nanocomposites, with high superparamagnetism, can be used in the following applications: drug targeting transports, drug carrier, and diagnosis assistant system.


2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.


2012 ◽  
Vol 616-618 ◽  
pp. 1797-1800
Author(s):  
Yu Mei Gong ◽  
Qing Liang ◽  
Jing Chuan Song ◽  
Ling Ming Xia

This paper presents the preparation of bimodal crystalline macro-/mesoporous titania powders by using a pluronic polymer (EO20PO70EO20, P123) as a template through a hydrothermal treatment. The as-prepared powders were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results reveal that the amount of P123 has a significant effect on the surface area of the mesoporous titania. When the mass ratio of P123:TBOT is 1:14, the crystalline macro-/mesoporous titania has the largest surface area (120.96 m2/g), the average pore diameter of this sample reaches a minimum of 6.67 nm.


2007 ◽  
Vol 7 (12) ◽  
pp. 4434-4438 ◽  
Author(s):  
Hyoun Woo Kim ◽  
Seung Hyun Shim ◽  
Jong Woo Lee

We reported the fabrication and characterization of MgO nanowires, which were grown by thermal evaporation of the mixture of MgB2 and Sn powders at 800 °C through a vapor-liquid-solid (VLS) process. We characterized as-synthesized MgO nanowires using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Sn nanoparticles were located at the tips of the nanowires, serving as catalyst for the growth of MgO nanowires. The produced nanowires were of cubic MgO structures with diameters in the range of 10–170 nm. The PL measurement with a Gaussian fitting exhibited visible light emission bands centered at 403, 576, and 720 nm.


2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.


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