SYNTHESIS AND FIELD EMISSION PROPERTIES OF SnS2 AND In-DOPED SnS2 WITH HIERARCHICAL STRUCTURE

NANO ◽  
2011 ◽  
Vol 06 (05) ◽  
pp. 489-496 ◽  
Author(s):  
H. X. ZHONG ◽  
C. X. WANG

A simple hydrothermal route was employed to prepare flower-like SnS2 and In -doped SnS2 by using biomolecular L-cysteine as sulfur source. The synthetic samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy in detail. Furthermore, the field emission from both the materials was investigated, it was found that both of them have excellent field emission properties, and the doped In has enhanced the field emission properties.

2011 ◽  
Vol 335-336 ◽  
pp. 460-463 ◽  
Author(s):  
Hong Mei Wang ◽  
Da Peng Zhou ◽  
Yuan Lian ◽  
Ming Pang ◽  
Dan Liu

Hexagonal flower-like CdS nanostructures were successfully synthesized through a facile hydrothermal method with thiourea as sulfur source. By combining the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), the structural and morphological characterizations of the products were performed. The photocatalytic activity of CdS nanostructures had been tested by degradation of Rhodamine B (RB) under UV light compared to commercial CdS powders, which indicated that the as-syntherized CdS nanostructures exhibited enhanced photocatalytic activity for degradation of RB. The possible growth mechanism of CdS nanostructures was proposed in the end.


Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yang Liu ◽  
Hongtao Yu ◽  
Xie Quan ◽  
Shuo Chen

MoS2/CdS photocatalyst was fabricated by a hydrothermal method for H2production under visible light. This method used low toxic thiourea as a sulfur source and was carried out at 200°C. Thus, it was better than the traditional methods, which are based on an annealing process at relatively high temperature (above 400°C) using toxic H2S as reducing agent. Scanning electron microscopy and transmission electron microscopy images showed that the morphologies of MoS2/CdS samples were feather shaped and MoS2layer was on the surface of CdS. The X-ray photoelectron spectroscopy testified that the sample was composed of stoichiometric MoS2and CdS. The UV-vis diffuse reflectance spectra displayed that the loading of MoS2can enhance the optical absorption of MoS2/CdS. The photocatalytic activity of MoS2/CdS was evaluated by producing hydrogen. The hydrogen production rate on MoS2/CdS reached 192 μmol·h−1. This performance was stable during three repeated photocatalytic processes.


Author(s):  
Z. Gu ◽  
L. Du ◽  
J.H. Edgar ◽  
E.A. Payzant ◽  
L. Walker ◽  
...  

AlN-SiC alloy crystals, with a thickness greater than 500 µm, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 °C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8° or 3.68°) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlN-SiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had the wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 106 cm−2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.


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.


Author(s):  
Katarzyna Matras-Postolek ◽  
A. Zaba ◽  
S. Sovinska ◽  
D. Bogdal

Zinc sulphide (ZnS) and zinc selenide (ZnSe) and manganese-doped and un-doped with different morphologies from 1D do 3D microflowers were successfully fabricated in only a few minutes by solvothermal reactions under microwave irradiation. In order to compare the effect of microwave heating on the properties of obtained  nanocrystals, additionally the synthesis under conventional heating was conducted additionally in similar conditions. The obtained nanocrystals were systematically characterized in terms of structural and optical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The photocatalytic activity of ZnSe, ZnS, ZnS:Mn and ZnSe:Mn nanocrystals with different morphologies was evaluated by the degradation of methyl orange (MO) and Rhodamine 6G (R6G), respectively. The results show that Mn doped NCs samples had higher coefficient of degradation of organic dyes under ultraviolet irradiation (UV).


2000 ◽  
Vol 15 (10) ◽  
pp. 2076-2079
Author(s):  
Chika Nozaki ◽  
Takashi Yamada ◽  
Kenji Tabata ◽  
Eiji Suzuki

Synthesis of a rutile-type lead-substituted tin oxide with (110) face was investigated. The characterization was performed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The homogeneous rutile-type lead-substituted tin oxide was obtained until 4.1 mol% of tin was substituted with lead. The surface of obtained oxide had a homogeneously lead-substituted (110) face.


Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.


2019 ◽  
Vol 9 (6) ◽  
pp. 1100 ◽  
Author(s):  
Xiangfeng Guan ◽  
Peihui Luo ◽  
Yunlong Yu ◽  
Xiaoyan Li ◽  
Dagui Chen

In this paper, we prepared mesoporous nickel cobaltite (NiCo2O4) nanostructures with multi-morphologies by simple solvothermal and subsequent heat treatment. By adjusting the solvent type, mesoporous NiCo2O4 nanoparticles, nanorods, nanowires, and microspheres were easily prepared. The as-prepared products were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) method. Furthermore, the catalytic activities towards the thermal decomposition of ammonium perchlorate (AP) of as-prepared NiCo2O4 nanostructures were investigated.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaowei Zhu ◽  
Kuisuo Yang ◽  
Anping Wu ◽  
He Bai ◽  
Jinrong Bao ◽  
...  

Abstract The novel submicro-spheres SiO2@LaPO4:Eu@SiO2 with core-shell-shell structures were prepared by connecting the SiO2 submicro-spheres and the rare earth ions through an organosilane HOOCC6H4N(CONH(CH2)3Si(OCH2CH3)3 (MABA-Si). The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (IR). It is found that the intermediate shell of the submicro-spheres was composed by LaPO4:Eu nanoparticles with the size of about 4, 5–7, or 15–34 nm. A possible formation mechanism for the SiO2@LaPO4:Eu@SiO2 submicro-spheres has been proposed. The dependence of the photoluminescence intensity on the size of the LaPO4:Eu nanoparticles has been investigated. The intensity ratios of electrical dipole transition 5D0 → 7F2 to magnetic dipole transition 5D0 → 7F1 of Eu3+ ions were increased with decreasing the size of LaPO4:Eu nanoparticles. According to the Judd-Ofelt (J-O) theory, when the size of LaPO4:Eu nanoparticles was about 4, 5–7 and 15–34 nm, the calculated J-O parameter Ω2 (optical transition intensity parameter) was 2.30 × 10−20, 1.80 × 10−20 and 1.20 × 10−20, respectively. The increase of Ω2 indicates that the symmetry of Eu3+ in the LaPO4 lattice was gradually reduced. The photoluminescence intensity of the SiO2@LaPO4:Eu@SiO2 submicro-spheres was unquenched in aqueous solution even after 15 days.


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