scholarly journals Preparation and Characterization of porous Carbon/Nickel Nanofibers for Supercapacitor

2013 ◽  
Vol 8 (4) ◽  
pp. 155892501300800 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Xin Xia ◽  
Hui Qiao ◽  
Yibing Cai ◽  
...  

Two polymer solutions of polyacrylonitrile, polyvinyl pyrrolidone, and Ni(CH3COOH)2 in dimethylformamide were electrospun into ternary composite nanofibers, followed by stabilization and carbonization processes to obtain porous carbon/nickel composite nanofibers with diameters of 100–200 nm. The study revealed that carbon/nickel composite nanofibers were successfully prepared, which allowed nickel particles with diameters of 20–70 nm to be uniformly distributed in the carbon nanofibers. It was also observed that the fibrous structures with particles embedded formed and the fibers broke into shorter fibers after sintering. X-ray diffraction indicated that embedded particles crystallized with the face centered cubic structure. The Brunauer-Emmett-Teller analysis revealed that carbon/nickel composite nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers. The specific capacitance of the composite nanofiber electrode was as high as 103.8 F/g and showed stable cyclicity (73.8%).

2013 ◽  
Vol 853 ◽  
pp. 101-104
Author(s):  
Da Wei Gao ◽  
Qu Fu Wei ◽  
Chun Xia Wang ◽  
Guo Liang Liu ◽  
Xue Mei He ◽  
...  

By employing the electrospinning technique and subsequent carbonization processes, porous carbon/nickle (C/Ni) composite nanofibers with diameters of 100-200 nm were successfully prepared. Two polymer solutions of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), and Ni (CH3COOH)2(Ni (OAc)2) were used as C/Ni composite nanofiber precursors. The study revealed that C/Ni composite nanofibers were successfully prepared and nickle particles with diameters of 20-70 nm were uniformly scattered in the carbon nanofibers. It was also observed that the fiber with clear fibrous morphology with particles broke into shorter fibers after sinter. X-ray diffraction (XRD) showed that these particles crystallized with the face centered cubic (FCC) structure. The Brunauer-Emmett-Teller (BET) analysis indicated that C/Ni composites nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers.


2008 ◽  
Vol 368-372 ◽  
pp. 1389-1391 ◽  
Author(s):  
Shuan Gui Qing ◽  
Bo Liu ◽  
Xun Liang ◽  
Hai Yang Li ◽  
Wei Zhong Lv ◽  
...  

Multilayer SiO2 crystals modified by alkoxysilanes were fabricated by the vertical deposition technique combined with self-assembly method. The SiO2 colloidal crystallization was prepared by the traditional Stöber-Fink-Bohn method, and modified by different alkoxysilanes to investigate the properties of the films. The films fabricated by the ordering of SiO2 spheres were investigated by infrared spectrometer, X-ray diffraction, scanning electron microscope, UV-visible spectrophotometer. The results showed that thin film is the face-centered cubic structures and the spheres are [111]-oriented.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Tizazu Abza ◽  
Dereje Gelanu Dadi ◽  
Fekadu Gashaw Hone ◽  
Tesfaye Chebelew Meharu ◽  
Gebremeskel Tekle ◽  
...  

Cobalt sulfide thin films were synthesized from acidic chemical baths by varying the deposition time. The powder X-ray diffraction studies indicated that there are hexagonal CoS, face-centered cubic Co3S4, and cubic Co9S8 phases of cobalt sulfide. The crystallite size of the hexagonal CoS phase decreased from 52.8 nm to 22.5 nm and that of the cubic Co9S8 phase increased from 11 nm to 60 nm as the deposition time increased from 2 hrs to 3.5 hrs. The scanning electron microscopic images revealed crack and pinhole free thin films with uniform and smooth background and few large polygonal grains on the surface. The band gap of the cobalt sulfide thin films decreased from 1.75 eV to 1.3 eV as the deposition time increased from 2 hrs to 3.5 hrs. The photoluminescence (PL) spectra of the films confirmed the emission of ultraviolet, violet, and blue lights. The intense PL emission of violet light at 384 nm had red shifted with increasing deposition time that could be resulted from the increase in the average crystallite size. The FTIR spectra of the films indicated the presence of OH, C-O-H, C-O, double sulfide, and Co-S groups. As the deposition time increased, the electrical resistivity of the cobalt sulfide thin films decreased due to the increase in both the crystallite size and the films’ thickness.


2010 ◽  
Vol 97-101 ◽  
pp. 19-22 ◽  
Author(s):  
Yu Shiang Wu ◽  
Wen Ku Chang ◽  
Min Jou

Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.


2015 ◽  
Vol 799-800 ◽  
pp. 120-124 ◽  
Author(s):  
Mary Donnabelle L. Balela ◽  
Lalaine M. Dulin ◽  
Erica A. Garcia ◽  
M. Janelle H. Tica

Cobalt-nickel (Co-Ni) nanowires were formed by electroless deposition in ethylene glycol under external magnetic field. The effects of initial Co (II) and Ni (II) concentration on the surface and morphology of the synthesized nanowires were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. An increase in the Co (II) concentration resulted in increase in diameter of the nanowires. However, the length of nanowires was observed to decrease. Higher Co (II) concentration resulted in a mixture of hexagonal close-packed and face-centered cubic Co-Ni nanowires. X-ray diffraction revealed that crystal growth occurred when the nanowires are annealed at 653 K for 10h.


2011 ◽  
Vol 335-336 ◽  
pp. 429-432 ◽  
Author(s):  
Xiu Yu Sun ◽  
Fa Qiang Xu

Highly ordered Cu, Ag and Au nanowire arrays with high aspect ratio and highly dense self-supporting nanowire patterns of copper group were successfully prepared using cyclic voltammetry with the assistance of anodic aluminum oxide (AAO) template. The X-ray diffraction (XRD) patterns of the metal nanowries were indexed to the face-centered cubic structure. The field emission scanning electron microscope (FE-SEM) results demonstrated that the length of nanowire could be controlled by changing the electrodepositon conditions. The aspect ratio of nanowire arrays can be tuned.


1994 ◽  
Vol 9 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Alan F. Jankowski ◽  
Mark A. Wall

The artificial layering of metals can change both physical and structural characteristics from the bulk. The stabilization of polymorphic metallic phases can occur on a dimensional scale that ranges from single overgrowth layers to repetitive layering at the nanoscale. The sputter deposition of crystalline titanium on nickel, as both a single layer and in multilayer form, has produced a face-centered cubic phase of titanium. The atomic structure of the face-centered cubic titanium phase is examined using high resolution electron microscopy in combination with electron and x-ray diffraction.


2006 ◽  
Vol 306-308 ◽  
pp. 1103-1108
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob

Nanocrystalline CeO2 has been synthesized at room temperature using water-in-oil (w/o) microemulsion technique. The structure and properties of the nanocrystalline CeO2 were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas adsorption desorption measurement. XRD results showed the synthesized CeO2 has a face centered cubic structure with crystallite size of about 5.2 nm. TEM observation also indicated the presence of nanometer sized particles of CeO2. Coarser particles were also observed due to agglomeration. Gas adsorption desorption isotherms showed the behavior of fine particles with mesoporous structure.


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Giordano T. Paganoto ◽  
Deise M. Santos ◽  
Tereza C. S. Evangelista ◽  
Marco C. C. Guimarães ◽  
Maria Tereza W. D. Carneiro ◽  
...  

This paper is consisted in the synthesis of platinum-based electrocatalysts supported on carbon (Vulcan XC-72) and investigation of the addition of gallium in their physicochemical and electrochemical properties toward ethanol oxidation reaction (EOR). PtGa/C electrocatalysts were prepared through thermal decomposition of polymeric precursor method at a temperature of 350°C. Six different compositions were homemade: Pt50Ga50/C, Pt60Ga40/C, Pt70Ga30/C, Pt80Ga20/C, Pt90Ga10/C, and Pt100/C. These electrocatalysts were electrochemically characterized by cyclic voltammetry (CV), chronoamperometry (CA), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS) in the presence and absence of ethanol 1.0 mol L−1. Thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were also carried out for a physicochemical characterization of those materials. XRD results showed the main peaks of face-centered cubic Pt. The particle sizes obtained from XRD and TEM analysis range from 7.2 nm to 12.9 nm. The CV results indicate behavior typical of Pt-based electrocatalysts in acid medium. The CV, EIS, and CA data reveal that the addition of up to 31% of gallium to the Pt highly improves catalytic activity on EOR response when compared to Pt100/C.


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