Hollow Crystals of BiFeO3 Prepared via a Al3+-Assisted Hydrothermal Method

2012 ◽  
Vol 174-177 ◽  
pp. 516-519
Author(s):  
Yong Gang Wang ◽  
Lin Lin Yang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Field Emission ◽  
Growth Mechanism ◽  
Irregular Shape ◽  
Morphology Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

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.

scholarly journals Nickel-Doped Cerium Oxide Nanoparticles: Green Synthesis Using Stevia and Protective Effect against Harmful Ultraviolet Rays

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4424 ◽  
Author(s):  
Mehrdad Khatami ◽  
Mina Sarani ◽  
Faride Mosazadeh ◽  
Mohammadreza Rajabalipour ◽  
Alireza Izadi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cerium Oxide ◽  
Field Emission ◽  
Cerium Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Ni Doping ◽  
X Ray ◽  
Scanning Electron

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.

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

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.

Preparation and Characterizations of a-Fe2O3 Nanorods and their Properties

2016 ◽  
Vol 852 ◽  
pp. 346-348
Author(s):  
Hong Cai ◽  
Qing Bo Du ◽  
Ji Gui Xu ◽  
Hong Wei Shi ◽  
Jun Zhu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Magnetic Measurement ◽  
Remnant Magnetization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Fundamental Research ◽  
Scanning Electron

a-Fe2O3 nanorods over large areas were successfully synthesized by hydrothermal method, using FeCl3 as iron source and PVP as surfactant. The as-synthesized a-Fe2O3 nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and magnetic measurement system (SQUID-VSM) . The results show that the nanorods prepared by hydrothermal method with the diameter of about 70 nm and the length of about 300 nm. The magnetic properties of the synthesized nanorods were studied, and the remnant magnetization and coercivity of the α-Fe2O3 nanorods at 300K are found to be 0.07emu/g and 2300Oe, respectively. The a-Fe2O3 nanorods reported here may have opportunities for both fundamental research and technological applications.

Microwave-Assisted Preparation of Cu2O Octahedral Microcrystals

2011 ◽  
Vol 284-286 ◽  
pp. 746-749
Author(s):  
Chong Hai Deng ◽  
Han Mei Hu ◽  
Ming Di Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Growth Mechanism ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Microwave Assisted ◽  
Morphology And Structure ◽  
Scanning Electron

In this paper, we reported a facile microwave-assisted green chemical route to prepare pure, uniform, and monodispersed Cu2O octahedron wrapped by the {111} faces by using glucose as a reducing agent. X-ray diffraction (XRD), energy dispersive X-ray spectrometry(EDX) and field emission scanning electron microscopy (FESEM) were used to characterize the as-synthesized products. It was found that the morphology and structure of Cu2O crystals were greatly affected by the concentration of NaOH. A solid-solution-solid growth mechanism was possibly proposed on the basis of the comparative experimental results.

Prepared of Flower-Like CuO via CTAB-Assisted Hydrothermal Method

2010 ◽  
Vol 152-153 ◽  
pp. 909-914 ◽  
Author(s):  
Yun Ling Zou ◽  
Yan Li ◽  
Nan Zhang ◽  
Jian Gang Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Cetyltrimethylammonium Bromide ◽  
Raw Material ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Scanning Electron

Flower-like CuO nanostructures have been prepared via cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. Here, CuCl2•2H2O was used as copper raw material, and sodium hydroxide was used as precipitate. The resulting CuO powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) pattern exhibited the nanocrystalline nature with monoclinic structure for the as-synthesized nanostructures. FESEM images indicated that the flower-like CuO nanostructures are composed of many interconnected nanosheets in size of several micrometers in length and width and 60-80 nm in thickness. The possible formation mechanism of flower-like CuO nanostructures was discussed.

Synthesis of Zinc Doped-Biphasic Calcium Phosphate Nanopowder via Sol-Gel Method

2012 ◽  
Vol 531-532 ◽  
pp. 614-617 ◽  
Author(s):  
Gunawan ◽  
I. Sopyan ◽  
A. Naqshbandi ◽  
S. Ramesh
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Phosphate ◽  
Field Emission ◽  
Biphasic Calcium Phosphate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Scanning Electron

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.

Adsorption and degradation of Congo red on a jarosite-type compound

RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 102972-102978 ◽  
Author(s):  
Yu Dong ◽  
Ziting Wang ◽  
Xin Yang ◽  
Meiying Zhu ◽  
Rufen Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Congo Red ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Compound ◽  
Forced Hydrolysis ◽  
Scanning Electron

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

Graphene-like nanostructures obtained from Biomass

2013 ◽  
Vol 1505 ◽  
Author(s):  
Gabriela Borin Barin ◽  
Yane Honorato Santos ◽  
Jennyfer Alves Rocha ◽  
Luiz Pereira da Costa ◽  
Antônio Gomes Souza Filho ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Coir Dust ◽  
Coconut Coir ◽  
Scanning Electron

ABSTRACTTwo dimensional (2D) carbon nanomaterials such as few graphite layers or graphene are extensively studied due to their unique properties suitable to be exploiting in a wide range of technological applications. Recently, the growth of high quality graphene monolayers using insects and waste as carbon precursors was reported in the literature. This methodology opened a new way to convert the waste carbon into a high-value-added product. In the present work coconut coir dust, an agroindustrial biomass, was used as biotemplate for preparing carbonaceous materials. Carbon structures were synthesized through pyrolysis under nitrogen atmosphere (100mL/min) at 500, 1000, and 1500°C during 2 hours. Starting materials were coconut coir dust in natura and coconut coir dust hydrothermally treated. The samples were characterized by X-ray diffraction, Raman Spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Raman spectra showed the D band for all samples, related to the presence of defects in sp2 carbon structure and G band, indicative of graphite crystallites. It was also observed that the sample carbonized at 1500°C from coconut coir dust treated by hydrothermal method showed G’ band at 2685cm-1 associated with the stacking order along the c-axis. X-ray diffraction analysis showed a broad peak around 2θ= 22° related to the presence of amorphous carbon. By increasing the pyrolysis temperature changes in XRD diffractograms were observed and the sample which was pyrolysed at 1500°C from coconut coir dust hydrothermally treated showed peaks at 2θ= 26.5°, 43° e 45° assigned to (002), (100) (101) graphite plans, respectively. Scanning electron microscopy images showed the presence of overlapping sheets and plates. Transmission Electron Microscopy (TEM) images of coconut coir dust in natura unveiled the formation of amorphous sheet. Coconut coir dust in natura and treated by the hydrothermal method pyrolysed at 1500°C, lead to the formation of some graphitic domains and few graphene layers.

Growth Mechanism and Characterization of Porous CuS Microspheres

2012 ◽  
Vol 568 ◽  
pp. 348-351
Author(s):  
Shuang Xu ◽  
Nuan Song ◽  
Chang Li Qiu ◽  
Yao Ping Zhang ◽  
Jian Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Mechanism ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this paper, a facile method was presented to fabricate CuS porous microspheres, which were formed by the intergrowth of CuS polycrystalline nanoslices. The obtained sample has been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electronic diffraction (SAED), and scanning electron microscopy (SEM). On the basis of the experimental results, we proposed a self-assemble mechanism to elucidate the formation of CuS nanoslice structure.

Synthesis of Na0.5Bi0.5TiO3 Microcubes via a Cr3+-Assisted Hydrothermal Route

2012 ◽  
Vol 463-464 ◽  
pp. 1497-1500
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Physical Properties ◽  
Hydrothermal Method ◽  
Significant Role ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Scanning Electron

Na0.5Bi0.5TiO3 microcubes with the side size ca. 20-30um were successfully fabricated by a Cr3+-assisted hydrothermal method. The obtained samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results show that Cr3+ played a significant role in the formation of Na0.5Bi0.5TiO3 microcubes. Possible mechanisms for the growth of Na0.5Bi0.5TiO3 microcubes are discussed. The results presented in this study would be important in investigating the correlation between morphology and basic physical properties, and may offer a route to control the morphology and size of crystals.

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