Preparation of hollow Fe3O4 spheres through a facile method and their applications

2017 ◽  
Vol 10 (06) ◽  
pp. 1750075 ◽  
Author(s):  
Xingping Wu ◽  
Aiping Zhu ◽  
Zhaodong Nan
Keyword(s):  
Saturation Magnetization ◽  
Ostwald Ripening ◽  
Solvothermal Method ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Solid Sphere ◽  
Small Particles ◽  
Potential Applications ◽  
One Step ◽  
Solid Spheres

Fe3O4 hollow microspheres with good dispersibility and high saturation magnetization were synthesized through a facile one-step solvothermal method. The formation mechanism of the hollow structure was studied by taking time-dependent experiments. Porous [Formula: see text]-FeOOH and [Formula: see text]-Fe2O3 nanosheets were firstly fabricated. Fe3O4 solid spheres aggregated by small particles were obtained from the transition of [Formula: see text]-FeOOH and [Formula: see text]-Fe2O3. Finally, the solid sphere is transferred to hollow sphere through Ostwald ripening. The maximum saturation magnetization of the hollow spheres is [Formula: see text][Formula: see text]emu/g, which is higher than some results reported in references. The Fe3O4 hollow spheres show potential applications in microwave absorption and photocatalysis.

Synthesis of Hollow ß-Phase GeO2 in Microemulsion

2013 ◽  
Vol 669 ◽  
pp. 360-365
Author(s):  
Xu Zou ◽  
Bing Bing Liu ◽  
Wei Wu ◽  
Dong Mei Li ◽  
Quan Jun Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ostwald Ripening ◽  
Hollow Structure ◽  
Simple Method ◽  
Light Emitting ◽  
Hollow Interior ◽  
Potential Applications ◽  
One Step ◽  
Average Size ◽  
20 Nm

We fabricated mono-dispersed hollow waxberry shaped ß-quartz GeO2by a facile one-step synthesis in emulsion at room temperature. TEM images indicated that hollow waxberry shaped GeO2were consisted of nano-sphere whose average size were estimated to be 20 nm. The growth mechanism and optical properties of the products were also investigated. The possible formation mechanism of the hollow interior is proposed as the Ostwald ripening. The optical properties of the ß-GeO2nanoparticles with hollow shapes were also studied with photoluminescence spectrum, which reveals a broad emission, suggesting potential applications in electronic and optoelectronic nanodevices. These attractive results provide us a new simple method further used to fabricate other specific hollow structure and indicate hollow waxberry shaped GeO2may have potential applications in light-emitting nanodevices.

Solvothermal Synthesis and Luminescence Properties of Gd2O2S:RE3+ (RE3+=Eu3+/Tb3+) Hollow Sphere

2019 ◽  
Vol 807 ◽  
pp. 1-10 ◽  
Author(s):  
Guang Xi Xu ◽  
Xiao Tong Sang ◽  
Jing Bao Lian ◽  
Nian Chu Wu ◽  
Xue Zhang
Keyword(s):  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Raw Materials ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Molar Ratio ◽  
Detailed Characterization ◽  
X Ray ◽  
Electronic Microscope

Eu3+ and Tb3+ ions singly activated Gd2O2S hollow spheres have been successfully synthesized via solvothermal method by using Gd (NO3)3, Eu (NO3)3, Tb (NO3)3 and thiourea as raw materials. Detailed characterization of the as-prepared samples were obtained by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), transmission electronic microscope (TEM) and photoluminescence (PL) spectroscopy. The results demonstrate that at 220 oC for 24 h, the molar ratio of thiourea/Gd3+ has no significant impact on the phase composition of Gd2O2S products. With the reaction time increased from 6 h to 24 h, the morphology of Gd2O2S samples changed from ellipsoidal to near-spheroidal structure, but still remained hollow structure. PL results show that the strongest emission peaks for Gd2O2S:Eu3+ and Gd2O2S:Tb3+ samples were centered at 625 nm and 545 nm, corresponding to the 5D0→7F2 transition of Eu3+ ions and 5D4→7F5 transition of Tb3+ ions, respectively. The quenching concentrations for Eu3+ and Tb3+ ions were 12% and 6%, which can be attributed to the exchange interaction for Eu3+ and Tb3+ ions, respectively.

Preparation and Photocatalysis Properties of TiO2/Graphene Nanocomposites

2012 ◽  
Vol 430-432 ◽  
pp. 1005-1008
Author(s):  
Dong Fang Wang ◽  
Da Chen ◽  
Guang Xing Ping ◽  
Chao Wang ◽  
Hai Zhen Chen ◽  
...  
Keyword(s):  
Solvothermal Method ◽  
Raw Materials ◽  
Chemical Oxidation ◽  
Graphene Nanocomposites ◽  
Photocatalytic Activities ◽  
Potential Applications ◽  
Tio2 Nanomaterials ◽  
One Step ◽  
20 Nm ◽  
Commercial Tio2

In this work, a novel photocatalyst with excellent photocatalytic activities was developed by the combination of TiO2 with graphene oxide (GO). GO was firstly prepared by the chemical oxidation of graphite through Hummers method and the subsequent dispersion and exfoliation in water. Then, GO and P25 nanoparticles (commercial TiO2) were used as raw materials to synthesize TiO2/graphene (TiO2/GE) nanocomposites by using a one-step solvothermal method. TEM images clearly showed that TiO2 nanomaterials (the size of about 15~20 nm) were distributed well onto the two-dimensional (2D) graphene sheets, indicating the formation of TiO2/GE nanocomposites. XRD results indicated that TiO2/GE nanocomposites exhibited TiO2 crystalline phase structure. Meanwhile, it was demonstrated from the methylene blue (MB) photodegradation results that TiO2/GE nanocomposites possessed excellent photocatalytic activities with potential applications.

Facile Synthesis and Luminescence Properties of Gd2O3:Eu3+ Hollow Spheres

2014 ◽  
Vol 998-999 ◽  
pp. 55-58
Author(s):  
Cui Miao Zhang ◽  
Jian Yuan Wang ◽  
Ya Min Liu ◽  
Guang Jia
Keyword(s):  
Hollow Spheres ◽  
Hollow Structure ◽  
Spherical Shape ◽  
Precipitation Method ◽  
Main Process ◽  
Flat Panel Displays ◽  
Light Emitting ◽  
Potential Applications ◽  
Biological Labeling ◽  
Aqueous Conditions

Well-dispersed, uniform Gd2O3:Eu3+ hollow microspheres have been successfully fabricated via a urea-based homogeneous precipitation method in the presence of colloidal carbon spheres as template, followed by subsequent heat treatment. The main process was carried out under aqueous conditions without any organic solvents, surfactants, or etching agents. The as-obtained Gd2O3:Eu3+ spheres with a spherical shape and hollow structure are uniform in size and distribution, and the diameters of the spheres and thickness of the shell are about 500 nm and 50 nm, respectively. The Gd2O3:Eu3+ hollow spheres exhibit strong red emission corresponding to the 5D0-7F2 transition of the Eu3+ ions under ultraviolet excitation, which might find potential applications in the fields such as light-emitting phosphors, advanced flat panel displays, or biological labeling.

scholarly journals One-Pot Synthesis of Cu2O/Cu Self-Assembled Hollow Nanospheres with Enhanced Photocatalytic Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Bo Zhou ◽  
Zhiguo Liu ◽  
Haijun Zhang ◽  
Yan Wu
Keyword(s):  
Photocatalytic Performance ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Light Illumination ◽  
One Pot ◽  
Thermal Synthesis ◽  
Synthesis Time ◽  
Visible Light Illumination ◽  
Template Free ◽  
Solid Spheres

Cu2O/Cu hollow spheres are prepared using one-pot template-free solvent-thermal synthesis route with (CH3COO)2Cu·H2O as a precursor. With the reaction time increasing gradually from 2 h to 20 h, the morphology of the Cu2O/Cu evolves from nanoparticle to hollow nanosphere. The hollow structure is obtained when the cooling rate falls down to 0.7°C/min. And the content of Cu in the hollow spheres also can be easily controlled by adjusting the solvent-thermal synthesis time. Using photocatalytic degradation of phenol as the probe molecules under visible-light illumination, we have investigated the influence of hollow structure on the photocatalytic activity of Cu2O/Cu. The prepared hollow sphere Cu2O/Cu particles exhibited a higher photodegradation capability than nanoparticles and solid spheres. When the content of Cu lies in the range of 11–86 wt%, the samples exhibit higher photocatalytic performance, indicating that the Cu2O/Cu particles with hollow structure are promising candidates for the processing of pollutants.

scholarly journals Constructing Carbon-Coated Fe3O4 Hierarchical Microstructures with a Porous Structure and their Excellent Cr(VI) Ion Removal Properties

2021 ◽  
Author(s):  
xiaoping wu ◽  
Lin Cheng ◽  
Chang-Sheng Song ◽  
Yi-Zhe Zhang ◽  
Xiao-Jing Shi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Magnetic Nanoparticles ◽  
Solvothermal Method ◽  
Hollow Spheres ◽  
High Capacity ◽  
Hollow Structure ◽  
Magnetic Composite ◽  
Ion Removal ◽  
Carbon Coated ◽  
Facile Solvothermal Method

Abstract Here, a facile solvothermal method coupled with an annealing strategy is developed to synthesize Fe3O4/carbon (Fe3O4@C) magnetic composite microstructures with different morphologies, including flower-like, hollow spheres and egg-like. Owing to the unique multi-porous and hollow structure, the as-prepared hierarchical Fe3O4@C hollow microspheres composite exhibit appealing performance as an absorbent of Cr(VI) ions in aqueous solution, delivering a high capacity of ca.197.2mg/g. Furthermore, the magnetic Fe3O4 ‘‘core’’ in composite hierarchical microstructures makes them easy to separate from aqueous systems by magnetic separation, the layer of carbon effectively prevents agglomerations of magnetic nanoparticles and expands their range of applications. The excellent Cr(VI) ions adsorbent activities of the Fe3O4@C magnetic composite microstructures would have a potential adsorbing material application in environmental purification.

Porous cerium dioxide hollow spheres and their photocatalytic performance

RSC Advances ◽  
2014 ◽  
Vol 4 (107) ◽  
pp. 62255-62261 ◽  
Author(s):  
Saisai Yuan ◽  
Qitao Zhang ◽  
Bin Xu ◽  
Zhengyuan Jin ◽  
Ya Zhang ◽  
...  
Keyword(s):  
Cerium Dioxide ◽  
Photocatalytic Performance ◽  
Ostwald Ripening ◽  
Solvothermal Method ◽  
Hollow Spheres ◽  
Ripening Process

Uniform-sized and monodiperse cerium dioxide porous hollow spheres (CeO2-PH) based on the Ostwald ripening process were fabricated by a simple solvothermal method in the absence of any templates.

One-step synthesis of MFe2O4 (M=Fe, Co) hollow spheres by template-free solvothermal method

2011 ◽  
Vol 509 (21) ◽  
pp. 6206-6211 ◽  
Author(s):  
Wangchang Li ◽  
Xiaojing Qiao ◽  
Qiuyu Zheng ◽  
Tonglai Zhang
Keyword(s):  
Solvothermal Method ◽  
Hollow Spheres ◽  
One Step ◽  
Template Free

Facile Solvothermal Method to Synthesis Eu Doped TiO2 Hollow Microspheres with Enhanced Photoluminescence

2013 ◽  
Vol 634-638 ◽  
pp. 2198-2202
Author(s):  
Jian Dong Zhuang ◽  
Hu Zhou ◽  
Qian Liu
Keyword(s):  
Solvothermal Method ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Europium Nitrate ◽  
Solvothermal Process ◽  
Uniform Size ◽  
Enhanced Photoluminescence ◽  
Facile Solvothermal Method ◽  
Calcination Treatment

Eu doped TiO2 powders have been prepared by the solvothermal process followed by calcination treatment. The furfural and dodecylamine assisted solvothermal method is a very simple way of fabricating porous TiO2 hollow spheres due to in situ hydrolysis and a self-assembled effect. By adding europium nitrate into the precursoSubscript textr solution, Eu-doped TiO2 hollow spheres with an intense photoluminescence were easily obtained. The stronger photoluminescence of Eu-doped TiO2 hollow sample can be attributed to the unique microstructures, such as uniform size distribution and the broken hollow structure, compared to solid Eu-TiO2 sample.

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