scholarly journals Effect of Lanthanum Doping on the Microstructure, Thermal Stability, and CO2 Adsorption Property of ZIF-8

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Sheng Wang ◽  
Shengquan Zhang ◽  
Xueyan Du ◽  
Yingying Shen ◽  
Zhiwei Ma

The reaction materials La(NO3)3·6H2O, Zn(NO3)2·6H2O, and 2-methylimidazole were mixed in a certain proportion. A research process innovatively adopts the parallel flow-drop solvothermal method and a lanthanum-doping method to achieve the synthesis of metal organic frameworks. In this study, we successfully introduce lanthanum into the framework of ZIF-8 to stabilize the spatial structure and improve its performance. The structure and properties of La-ZIF-8 were characterized by the X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry analysis (TGA), and fourier transform infrared spectroscopy (FTIR). The relationship between microstructure stability and macroscopical properties is illustrated. The results show that the doping of lanthanum is beneficial for improving the thermal stability and CO2 adsorption property of ZIF-8 because of the improvement in the microstructure. The introduction of lanthanum to the ZIF-8 is also beneficial for forming porous frameworks and raising the thermal stability and CO2 adsorption properties. The crystallinity, structure, morphology, and thermal stability of La-ZIF-8 are optimal at the La content of 2 atom.%.

2021 ◽  
Vol 897 ◽  
pp. 57-62
Author(s):  
Omneya A. Koriem ◽  
Ahmed H. El-Shazly ◽  
Marwa F. El-Kady

UiO-66 is a zirconium-based metal organic framework (MOF). It was synthesized and used by researchers due to its high water, chemical and thermal stability. The mentioned reasons in addition to other excellent properties made them a highly competitive materials for a variety of industrial problems. This study investigates the effect of the reaction time on the characteristics of the prepared UiO-66 nanoparticles. UiO-66 was synthesized by the solvothermal method and the reaction was left to take place for 18, 21 and 24 hours. UiO-66 was characterized using X-ray Diffraction (XRD) and Fourier-Transform Infrared (FTIR), the results showed that it has the same patterns and functional groups of the previously reported UiO-66. In addition, Scanning Electron Microscopy (SEM) was used to confirm the morphology of UiO-66. The smallest particle size around 200 nm was obtained at 18 hours. To investigate the thermal stability of the prepared UiO-66, Thermogravimetry analysis (TGA) was conducted. The results matched well with the literature and confirm that UiO-66 is thermally stable up to 500°C.


2018 ◽  
Vol 8 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Sheng Wang ◽  
Zhiwei Ma ◽  
Xueyan Du ◽  
Shengquan Zhang ◽  
Zhenbin Chen

2010 ◽  
Vol 59 (4) ◽  
pp. 733-740 ◽  
Author(s):  
M. P. Yutkin ◽  
M. S. Zavakhina ◽  
D. G. Samsonenko ◽  
D. N. Dybtsev ◽  
V. P. Fedin

2016 ◽  
Vol 643 ◽  
pp. 91-97 ◽  
Author(s):  
D. Ecija ◽  
M. Marschall ◽  
J. Reichert ◽  
A. Kasperski ◽  
D. Nieckarz ◽  
...  

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.


2021 ◽  
Vol 875 ◽  
pp. 116-120
Author(s):  
Muhammad Alamgir ◽  
Faizan Ali Ghauri ◽  
Waheed Qamar Khan ◽  
Sajawal Rasheed ◽  
Muhammad Sarfraz Nawaz ◽  
...  

In this study, the effect of SBR concentration (10 Phr, 20 Phr & 30 Phr ) on the thermal behavior of EPDM/SBR blends was studied. Thermogravimetric analysis (TGA) was used to check weight loss of samples as function of temperature by heating upto 600°C. X-ray diffraction (XRD) was performed to determine quality and % crystallinity of the elastomer blends. It was seen that % crystallinity improved with an increase in the content of SBR in EPDM/SBR blends. TGA revealed that the thermal stability of EPDM/SBR blends has improved by 17% than neat EPDM. Carbon nano-coatings produced by sputtering have no beneficial influence on thermal behaviour of elastomers.


2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.


2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.


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