W-Doped VO2 (M) with Tunable Phase Transition Temperature

2013 ◽  
Vol 320 ◽  
pp. 483-487 ◽  
Author(s):  
Ming Li ◽  
Deng Bing Li ◽  
Jing Pan ◽  
Guang Hai Li

W-doped VO2 (B) nanoneedles were successfully synthesized by solgel combing with hydrothermal treatment, in which the polyethylene glycol (PEG) was used as both surfactant and reducing. The metastable VO2 (B) was completely transformed to thermochromic VO2 (M) after annealing at high purity N2 atmosphere. The DSC results exhibit a strong crystallographic transition, and the phase transition temperature of VO2 (M) can be reduced to about 38 °C by W-doping. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) were used to characterize the morphology and crystalline structure of the samples. The variable-temperature infrared transmittance spectra of VO2 (M) demonstrate their potential applications in energy saving field.

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.


2009 ◽  
Vol 48 (9) ◽  
pp. 09KF01 ◽  
Author(s):  
Yasuhiro Yoneda ◽  
Yoshiki Kohmura ◽  
Yoshio Suzuki

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Billy N. Cardoso ◽  
Emerson C. Kohlrausch ◽  
Marina T. Laranjo ◽  
Edilson V. Benvenutti ◽  
Naira M. Balzaretti ◽  
...  

TiO2/SiO2 nanoparticles with 3, 5, and 10 molar percent of silica, were synthesized by hydrothermal method and characterized by SEM, TEM, N2 adsorption-desorption isotherms, X-ray diffraction, and Raman and UV-Vis spectroscopy. While pristine TiO2 thermally treated at 500°C presents a surface area of 36 m2 g-1 (±10 m2 g-1), TiO2/SiO2 containing 3, 5, and 10 molar percent of silica present surface areas of 93, 124, and 150 m2 g-1 (±10 m2 g-1), respectively. SiO2 is found to form very small amorphous domains well dispersed in the TiO2 matrix. X-ray diffraction and Raman spectroscopy data show that anatase-to-rutile phase transition temperature is delayed by the presence of SiO2, enabling single-anatase phase photoanodes for DSSCs. According to the I×V measurements, photoanodes with 3% of SiO2 result in improved efficiency, which is mainly related to increased surface area and dye loading. In addition, the results suggest a gain in photocurrent related to the passivation of defects by SiO2.


2012 ◽  
Vol 548 ◽  
pp. 138-142
Author(s):  
Xiao Ying Liu ◽  
Xiao Dong Hao ◽  
Chun Xiang Gu ◽  
Yu Xin Zhang ◽  
Xin Lu Li ◽  
...  

In this work, TiO2nanoparticles (NPs) were prepared through a well-developed hydrothermal method. The dry products were characterized by digital camera, transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric method (TGA). These results suggested that TiO2NPs were well-crystallized and oleic acid-capped (OA-capped; 33.42 wt.%). In order to investigate the flocculation and stability of TiO2NPs colloids, redispersed experiments were carried out by altering the preparative parameters (e.g., redispersion solvent, washing times). In addition, the compounding stability of TiO2NPs colloids with AuNPs colloids and MnO4-solution under processing conditions (e.g., aging with stirring and under UV irradiation) were also studied. In principle, systematic investigations of flocculation and stability of TiO2NPs will be useful for their potential applications including novel photocatalysts and biosensors.


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.


2010 ◽  
Vol 25 (7) ◽  
pp. 1272-1277 ◽  
Author(s):  
Jinjian Zheng ◽  
Zhiming Wu ◽  
Weihuang Yang ◽  
Shuping Li ◽  
Junyong Kang

Type II ZnO/ZnSe core/shell nanowire arrays were grown by a two-step chemical vapor deposition. The nanowire arrays with dense nanoislands on the surface are well aligned and normal to the substrate imaged by scanning electron microscopy. The core/shell structure of nanowires was identified by a high-resolution transmission electron microscopy. The structure and composition of the shell were confirmed to be wurtzite ZnSe by x-ray diffraction, Raman scattering and energy-dispersive x-ray spectroscopy. Moreover, an intense emission was observed at 1.89 eV smaller than the band gaps of core and shell materials by photoluminescence, indicating the achievement of the type II band alignment at the interface. This study is expected to contribute to the potential applications in novel photovoltaic devices.


2011 ◽  
Vol 52-54 ◽  
pp. 1884-1889 ◽  
Author(s):  
Dariush Jafar Khadem ◽  
Zahira Yaakob ◽  
Samaneh Shahgaldi ◽  
Wan Ramli Wan Daud ◽  
Edy Herianto Majlan

Metal and Metal oxide nanofibers have different potential to play an essential role in a series of application, among them copper and copper oxide nanostructures is a promising semiconductor material with potential applications in many field. In this paper, electrospinning method via sol-gel was used to fabricate copper and copper oxide nanofibers. Synthesize of copper and copper oxide nanofibers and also effect of calcinations temperature on morphology investigated by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Rijing Wang ◽  
Xiaohong Wang ◽  
Xiaoguang Xi ◽  
Ruanbing Hu ◽  
Guohua Jiang

A simple sol-gel method was used to prepare magnetic Fe3O4/SiO2/TiO2composites with core-shell structure. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) have been applied to investigate the structure and morphology of the resultant composites. The obtained composites showed excellent magnetism and higher photodegradation ability than pure TiO2. The photocatalytic mechanism was also discussed. The magnetic composites should be extended to various potential applications, such as photodegradation, catalysis, separation, and purification processes.


2014 ◽  
Vol 609-610 ◽  
pp. 76-81 ◽  
Author(s):  
Ling Wei Hu ◽  
Hua Tian ◽  
Yu Xia Zhang ◽  
Kun Lu ◽  
Ai Hua Jing

ZnO/graphene composites has been synthesized using a one-pot hydrothermal method at moderate temperature of 90°C. Hydrothermal growth was done in an aqueous solution consisting of 20 mL graphene oxide (GO) solution (0.25 mg/mL) with equimolar of zinc acetate [ZAc, Zn (CH3COO)2·2H2 and hexamethylenetetramine (HMTA, C6H12N4). The as-synthesized composites was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results of the characterization indicate that GO was reduced to graphene in the growth process, while ZnO in the form of quantum dots (QDs) or nanoparticles embedded in the graphene sheet. The composites synthesized by this method will have potential applications in bioimaging, gas sensing, optoelectrical materials and devices. The photoluminescence (PL) of the conposites was also investigated.


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