scholarly journals Heterogeneous Cu–Fe oxide catalysts for preferential CO oxidation (PROX) in H2-rich process streams

RSC Advances ◽  
2020 ◽  
Vol 10 (59) ◽  
pp. 35792-35802
Author(s):  
Venkata D. B. C. Dasireddy ◽  
Krish Bharuth-Ram ◽  
Darko Hanzel ◽  
Blaž Likozar

Fe loading in Cu–Fe phases and its effect on carbon monoxide oxidation in H2-rich reactant streams were investigated with the catalyst material phases characterized by Field Emission Scanning Electron Microscopy, X-ray diffraction studies and Mössbauer Spectroscopy.

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4424 ◽  
Author(s):  
Mehrdad Khatami ◽  
Mina Sarani ◽  
Faride Mosazadeh ◽  
Mohammadreza Rajabalipour ◽  
Alireza Izadi ◽  
...  

Nanoparticles of cerium oxide CeO2 are important nanomaterials with remarkable properties for use in both industrial and non-industrial fields. In a general way, doping of oxide nanometric with transition metals improves the properties of nanoparticles. In this study, nickel- doped cerium oxide nanoparticles were synthesized from Stevia rebaudiana extract. Both doped and non-doped nanoparticles were characterized by X-ray diffraction, Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray, Raman spectroscopy, and Vibrating-Sample Magnetometry analysis. According to X-ray diffraction, Raman and Energy Dispersive X-ray crystalline and single phase of CeO2 and Ni doped CeO2 nanoparticles exhibiting fluorite structure with F2g mode were synthesized. Field Emission Scanning Electron Microscopy shows that CeO2 and Ni doped nanoparticles have spherical shape and sizes ranging of 8 to 10 nm. Ni doping of CeO2 results in an increasing of magnetic properties. The enhancement of ultraviolet protector character via Ni doping of CeO2 is also discussed.


2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin

Nanostructured CaWO4, CaWO4:Eu3+, and CaWO4:Tb3+ phosphor particles were synthesized via a facile sonochemical route. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, low voltage cathodoluminescence spectra, and photoluminescence lifetimes were used to characterize the as-obtained samples. The X-ray diffraction results indicate that the samples are well crystallized with the scheelite structure of CaWO4. The transmission electron microscopy and field emission scanning electron microscopy images illustrate that the powders consist of spherical particles with sizes from 120 to 160 nm, which are the aggregates of even smaller nanoparticles ranging from 10 to 20 nm. Under UV light or electron beam excitation, the CaWO4 powder exhibited a blue emission band with a maximum at 430 nm originating from the WO2−4 groups, while the CaWO4:Eu3+ powder showed red emission dominated by 613 nm ascribed to the 5D0 → 7F2 of Eu3+, and the CaWO4:Tb3+ powders showed emission at 544 nm, ascribed to the 5D4 → 7F5 transition of Tb3+. The PL excitation and emission spectra suggest that the energy is transferred from WO2−4 to Eu3+CaWO4:Eu3+ and to Tb3+ in CaWO4:Tb3+. Moreover, the energy transfer from WO2−4 to Tb3+ in CaWO4:Tb3+ is more efficient than that from WO2−4 to Eu3+ in CaWO4:Eu3+. This novel and efficient pathway could open new opportunities for further investigating the novel properties of tungstate materials.


2012 ◽  
Vol 531-532 ◽  
pp. 614-617 ◽  
Author(s):  
Gunawan ◽  
I. Sopyan ◽  
A. Naqshbandi ◽  
S. Ramesh

Biphasic calcium phosphate powders doped with zinc (Zn-doped BCP) were synthesized via sol-gel technique. Different concentrations of Zn have been successfully incorporated into biphasic calcium (BCP) phases namely: 1%, 2%, 3%, 5%, 7%, 10% and 15%. The synthesized powders were calcined at temperatures of 700-900°C. The calcined Zn-doped BCP powders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential and thermogravimetric analysis (TG/DTA) and field-emission scanning electron microscopy (FESEM). X-ray diffraction analysis revealed that the phases present in Zn-doped are hydroxyapatite, β- TCP and parascholzite. Moreover, FTIR analysis of the synthesized powders depicted that the bands of HPO4 increased meanwhile O-H decreased with an increase in the calcination temperature. Field emission scanning electron microscopy (FESEM) results showed the agglomeration of particles into microscale aggregates with size of the agglomerates tending to increase with an increase in the dopant concentration.


RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 102972-102978 ◽  
Author(s):  
Yu Dong ◽  
Ziting Wang ◽  
Xin Yang ◽  
Meiying Zhu ◽  
Rufen Chen ◽  
...  

Natrojarosite particles were prepared by forced hydrolysis. X-ray diffraction and field-emission scanning electron microscopy were used to characterize the resulting products.


2012 ◽  
Vol 174-177 ◽  
pp. 516-519
Author(s):  
Yong Gang Wang ◽  
Lin Lin Yang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

The BiFeO3 hollow crystals were successfully prepared at 200oC by a Al3+assisted hydrothermal method. The structures and morphologies of the as-obtained products were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM). A morphology evolution from irregular shape to square, hollow, and sphere-like was observed as the Al ions concentration varied from 0% to 1.5%. The possible growth mechanism of the BiFeO3hollow crystals was also discussed.


2015 ◽  
Vol 1754 ◽  
pp. 129-134
Author(s):  
Sanjay Kr. Jana ◽  
Saptarsi Ghosh ◽  
Syed Mukulika Dinara ◽  
Apurba Chakraorty ◽  
D. Biswas

AbstractThe work presents a comparative study on GaN/AlGaN type-II heterostructures grown on c-plane Al2O3 and Si (111) substrates by Plasma Assisted Molecular Beam Epitaxy. The in-depth structural characterizations of these samples were performed by High-Resolution X-Ray Diffraction, X-ray Reflectivity and Field Emission Scanning Electron Microscopy. The in-plane and out-of plane strains were determined from measured c- and a-lattice parameters of the epilayers from reciprocal space mapping of both symmetric triple axis (002) and asymmetric grazing incidence (105) double axis mode. The mosaicity parameters like tilt and correlation lengths were also calculated from reciprocal space mapping. Moreover, the twist angle was measured from skew symmetric off axis scan of (102), (103), and (105) planes along with (002) symmetric plane. The defect density were measured from the full width at half maxima of skew symmetric scan of (002) and (102) reflection planes. Also, the strained states of all the layers were analyzed and corresponding Al mole fraction was calculated based on anisotropic elastic theory. The thicknesses of the layers were measured from simulation of the nominal structure by fitting with X-ray Reflectivity experimental curves and also by comparing with cross sectional Field Emission Scanning Electron Microscopy micrographs.


2012 ◽  
Vol 535-537 ◽  
pp. 797-800
Author(s):  
Liang Luo ◽  
Yan Jun Zhu ◽  
Ling Ling Song ◽  
Xiao Bo Zhang

A facile one-pot hydrothermal method has been developed for synthesis of porous and non-porous BaTiO3 ceramics using Ba(OH)2.8H2O, BaCO3 as barium source. In this paper, we research the effect of different barium source on the nanostructure of BaTiO3 ceramics in a solid state reaction, and the results indicated that the two different morphologies of BaTiO3 ceramics can be easily prepared by using these two different barium source. The phase composition and morphology of the as-obtained products were investigated by X-ray diffraction and field emission scanning electron microscopy (SEM).


2015 ◽  
Vol 819 ◽  
pp. 251-255
Author(s):  
M. Muhammad Safwan ◽  
Hui Lin Ong ◽  
Hazizan Md Akil

The work described in this paper is the extraction of microcrystalline cellulose from Elaeis Guineensis Jacquin Frond using alkaline and bleaching treatment. Microcrystalline cellulose extracted has been characterized by X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). Morphological investigation of fibers was performed using field emission scanning electron microscopy (FESEM) where rod like fiber can be observed. Crystallinity of cellulose extracted was found higher than raw material.


2016 ◽  
Vol 846 ◽  
pp. 434-439 ◽  
Author(s):  
Fauziah Abdul Aziz ◽  
Ariffin Ismail ◽  
Wan Yunus Wan Md Zin ◽  
Norazman Mohamad Nor ◽  
Risby Mohd Sohaimi ◽  
...  

Cellulose Micro/Nano fibers (CMNF) from various plants which is Resak (Vatica spp.) waste, Merbau (Intsia bijuga) waste, banana (Musa acuminata) pseudo-stem and pineapple (Ananas comosus) leaf fibers have been isolated and characterized. Isolation of microfibril cellulose from raw fibers was achieved using alkaline treatment and bleaching. The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Characterizations of treated and untreated samples were compared. The comparison between those treated and untreated samples giving different crystallite size, crystallinity, arrangement of CMNF and surface morphology from different plants. Hence, with these information different nanocomposite from CMNF can be constructed and manipulated for various application.


2011 ◽  
Vol 284-286 ◽  
pp. 654-657 ◽  
Author(s):  
Ling Liu ◽  
Tian Xi Wang ◽  
Yong Cai Zhang ◽  
Ming Zhang

ZnO2nanoparticles were synthesized via hydrothermal reaction between Zn5(CO3)2(OH)6powder and 30 mass% H2O2aqueous solution at 80 °C for 24 h, and ZnO powders with granular and rodlike morphologies were synthesized via hydrothermal decomposition of the as-synthesized ZnO2nanoparticles in water at 150-170 °C for 24 h. The obtained products were characterized by X-ray diffraction, Raman and Field emission scanning electron microscopy.


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