Capacitive Study of Ni(OH)2 Xerogels in KOH Solution

2012 ◽  
Vol 608-609 ◽  
pp. 1106-1110
Author(s):  
Xin Jin Tian ◽  
Jie Cheng ◽  
Yue Hua Wen ◽  
Gao Ping Cao ◽  
Han Min Liu

Ni(OH)2 xerogels were formed by sol-gel method at 80 °C followed drying at 110 °C and ambient pressure. The structure of Ni(OH)2 xerogels was characterized using X-ray diffraction, transmission electron microscope (TEM) and N2 (77K) adsorption. X-Ray Diffraction (XRD) results showed that the material obtained has a crystalline -Ni(OH)2. TEM images showed that average size of the crystalline phase is about 10 nm. Results of N2 (77K) adsorption isotherm showed that the (BET) specific surface area is 232 m2/g and the Pore size distribution is in the regime 1-4 nm (Barrett–Joyner–Halenda, BJH). The Ni(OH)2 xerogels electrodes were activated using cyclic voltammetry, and their capacitive performance was evaluated using cyclic voltammetry (CV) and constant current discharge. The Ni(OH)2 xerogels electrodes exhibited excellent capacitive behavior with a specific capacitance of 635 F/g (calculated by CV). High performance obtained indicates that the Ni(OH)2 xerogels are promising electrode materials for supercapacitors, and the electrochemical activation of these electrodes is doable.

2012 ◽  
Vol 608-609 ◽  
pp. 1092-1096
Author(s):  
Jie Cheng ◽  
Xin Jin Tian ◽  
Yue Hua Wen ◽  
Yan Xu ◽  
Han Min Liu ◽  
...  

Ni0.76Co0.24Ox xerogels were formed by the sol-gel method followed by heat-treatment in air. The structure and properties of these materials were characterized by using X-ray diffraction, TEM and N2 (77K) adsorption. Electrodes with the xerogels were activated by cyclic voltammetry (CV) and their capacitive performance was evaluated by galvanostatic technique in 7 mol/L KOH solutions. A maximum specific capacitance of 904 F/g was obtained by constant current discharge with a current density of 2.0 mA/cm2 for the Ni0.76Co0.24Ox xerogels heat-treated at 250°C. High performance obtained indicates that these materials are promising electrode materials for supercapacitors.


2021 ◽  
Vol 21 (11) ◽  
pp. 5592-5602
Author(s):  
Samira Almasi ◽  
Ali Mohammad Rashidi

The effect of the yttria-stabilized zirconia (YSZ) nanoparticle loading in an electro-less bath was considered as one of the vital synthesis variables for control Ni content and microstructure of prepared nanocomposite particles, which are two crucial factors to achieving high-performance SOFC anode. Nanocomposite particles were prepared using a simple electroless method without any expensive pretreatment of sensitizing by Sn2+ ions as well as activating by Pd2+ ions that are usually used to apply nickel coating on the surface of a non-conductive substrate. The process was performed by adding YSZ nanoparticles into NaOH solution, separating them from the solution by the centrifugal method, then providing several water-based nanofluids with different concentrations of activated YSZ nanoparticles, mixing them with NiCI2 solution, followed by adding the hydrazine and then NaOH solution. X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis were used to analyze the prepared nanocomposite particles. It is observed that after adding YSZ nanoparticles into the NaOH solution, the pH of the solution varied gradually from a starting pH of 10.2 to 9. Also, by increasing the YSZ nanoparticles loading in the electroless bath from 76 mg/l to 126 mg/l, the grain size of Ni deposits, the Ni content and the average size of the prepared nanocomposite particles decreased. The electrochemical mechanism previously proposed for the nickel ion reduction was modified, and a novel analytical model was proposed for variation of the efficiency of Ni deposition with YSZ nanoparticles loading.


Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1912
Author(s):  
Zheng Li ◽  
Yaogang Wang ◽  
Wen Xia ◽  
Jixian Gong ◽  
Shiru Jia ◽  
...  

Heteroatom doping is an effective way to raise the electrochemical properties of carbon materials. In this paper, a novel electrode material including nitrogen, phosphorus, and sulfur co-doped pyrolyzed bacterial cellulose (N/P/S-PBC) nanofibers was produced. The morphologies, structure characteristics and electrochemical performances of the materials were investigated by Scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction patterns, X-ray photoelectronic spectroscopy, N2 sorption analysis and electrochemical measurements. When 3.9 atom% of nitrogen, 1.22 atom% of phosphorus and 0.6 atom% of sulfur co-doped into PBC, the specific capacitance of N/P/S-PBC at 1.0 A/g was 255 F/g and the N/P/S-PBC supercapacitors’ energy density at 1 A/g was 8.48 Wh/kg with a power density of 489.45 W/kg, which were better than those of the N/P-PBC and N/S-PBC supercapacitors. This material may be a very good candidate as the promising electrode materials for high-performance supercapacitors.


NANO ◽  
2020 ◽  
Vol 15 (02) ◽  
pp. 2050017
Author(s):  
Ke-Cheng Yang ◽  
Li-Hui Xu ◽  
Hong Pan ◽  
Li-Ming Wang ◽  
Yong Shen ◽  
...  

In this study, CuS/SiO2 composite modified aerogel was prepared by the incorporation of hollow spherical CuS into methyltrimethoxysilane-based SiO2 sol and modification with hexadecafluorodecyltriethoxysilane via acid-base catalyzed sol–gel reaction and drying under ambient pressure. The CuS/SiO2 composite modified aerogel was characterized by Fourier-transform infrared (FT-IR) spectrometry, scanning electron microscope (SEM), nitrogen gas adsorption and desorption and X-ray diffraction (XRD), respectively. The effects of CuS and fluorosilane concentration on density and porosity of aerogel, oleophobic and photocatalytic properties were evaluated. The results showed that structure and physical properties of aerogel had some effect by introducing CuS and fluorosilane, and the CuS/SiO2 composite modified aerogel with density of 0.146[Formula: see text]g/cm3 and specific surface area of 241[Formula: see text]m2/g achieved super-oleophobicity with oil contact angle of 152.8∘ and sliding angle of 10∘, and good photocatalytic properties for methylene blue.


2012 ◽  
Vol 535-537 ◽  
pp. 2240-2244
Author(s):  
Wei Wei ◽  
Chang Shun Yu ◽  
Shao Jun Wang ◽  
Qing Da An

Nanosized TiO2 particles were synthesized by sol-gel method using ionic liquid as assistant. The samples were characterized by UV-vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM). It was shown that the phase detectable was mainly rutile phase with uniform sphericity and the average size was 10nm. Along with the rise of sintering temperature, grain diameter became bigger. The photocatalytic activities of nanosized TiO2 were evaluated by the reduction yield in the presence of CO2 and water. The result showed that TiO2 catalysts has efficient photocatalytic activities, of which made with [OMIM]BF4 displayed the highest photocatalytic active in the experiment.


1994 ◽  
Vol 346 ◽  
Author(s):  
Carol S. Houk ◽  
Gary A. Burgoine ◽  
Catherine J. Page

ABSTRACTWe have investigated the homogeneity of sol‐gel derived YBa2Cu307‐s from the solution phase to the final product using transmission electron microscopy (TEM), x‐ray diffraction (XRD), and Energy Dispersive X‐ray (EDX) lateral mapping techniques. The starting solutions contain stoichiometric amounts of the metal 2‐(2‐methoxyethoxy)ethoxide components in 2‐(2‐methoxyethoxy)ethanol and appear to be homogeneous by TEM with a uniform distribution of particles having an average size of less than 40 â. Through elemental mapping we see elemental segregation in the high temperature (950 °C) products, which are orthorhombic by XRD. In elemental maps of gel samples fired to 700 °C, which are tetragonal by XRD, we also see elemental inhomogeneity within particles and phase zoning in maps of products from finely ground gels. A comparison of elemental maps and x‐ray diffraction patterns of the products from gel processing and conventional solid state processing is made.


2021 ◽  
Vol 10 (2) ◽  
pp. 26-31
Author(s):  
Dewi Ramayani ◽  
Yanuar Hamzah ◽  
Erman Taer ◽  
Novi Yanti ◽  
Afriwandi Apriwandi

Abstrak. Pengembangan sistem penyimpanan energi elektrokimia yang efektif dan efisien menjadi sangat penting pada era evolusi teknologi dan industri modern saat ini. Penelitian ini mengemukakan karbon aktif sebagai bahan dasar material elektroda untuk diaplikasikan pada piranti penyimpan energi, khsusunya superkapasitor melalui analisa densitas, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) dan Cyclic Voltammetry (CV). Karbon aktif berbentuk monolit disiapkan dari ampas jus wortel melalui pendekatan pirolisis satu tahap terintegrasi dan aktivasi kimia KOH. Proses pirolisis satu tahap terintegrasi dilakukan melalui penggabungan karbonisasi dan aktivasi fisika dalam atmosfer gas N2/CO2. Berdasarkan analisis data, karbon aktif menunjukkan sifat amorf yang normal dan sifat porositas terkonfirmasi. Lebih lanjut, sifat elekrokimia dievaluasi menggunakan metode Cyclic Voltammetry (CV) pada sistem dua elektroda. Kapasitansi spesifik yang dihasilkan sebesar 155 F/g dalam elektrolit 1 M H2SO4 dengan energi spesifik dan daya spesifik adalah 21,52 Wh/kg dan 77,57 W/kg. Berdasarkan analisa ini maka ampas jus wortel terkonfirmasi berpotensi sebagai karbon aktif untuk elektroda yang diaplikasikan dalam piranti penyimpan energi superkapasitor.Abstract. The development of an effective and efficient electrochemical energy storage system is very important in today's era of technological evolution and the modern industry. This research suggests that activated carbon is the raw material for electrode materials to be applied to energy storage devices, especially supercapacitors through density analysis, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and Cyclic Voltammetry (CV). Activated carbon in the monolith form derived from carrot juice waste was prepared through a one-stage integrated pyrolysis approach and chemical activation of KOH. An integrated one-stage pyrolysis process was carried out by combining carbonization and physical activation in an N2/CO2 gas atmosphere. Based on data analysis, activated carbon performed normal amorphous behavior with confirmed porosity features. Furthermore, the electrochemical properties were evaluated using the Cyclic Voltammetry (CV) method at the two-electrode system. The specific capacitance was found as high as 155 F/g in the 1 M H2SO4 aqueous electrolyte with specific energy and specific power as high as 21.52 Wh/kg and 77.57 W/kg, respectively. Based on this analysis, the carrot juice waste has been confirmed to have the potential as activated carbon for the electrodes applied in supercapacitor energy storage technology.Keywords: Carrot Juice Waste, Activated Carbon, Electrode Materials, Supercapacitor


1996 ◽  
Vol 453 ◽  
Author(s):  
Audrey J. Babcock ◽  
Alexander R. Pico ◽  
Catherine J. Page

AbstractWe have developed an ambient-pressure sol-gel synthetic route to superconducting borate-doped Sr2CuO2(CO3) using polyether alkoxide precursors. In our sol-gel preparation, the starting solutions contain strontium and copper alkoxide complexes in 2-(2-methoxy-ethoxy)ethanol. Boron is incorporated into the solution by using an aqueous boric acid solution for hydrolysis. Dried gels were examined by x-ray diffraction and thermal gravimetric analysis. By experimenting with various firing sequences and atmospheres we have established a successful route for reproducibly preparing relatively pure Sr2CuO2CO3 and boron-doped phases. Final products were characterized by x-ray diffraction, elemental analysis and magnetic susceptibility. Samples of nominal composition Sr2CuO2(CO3)0.85(BO2)0.15 are superconducting with a Tc(onset) of ∼25K. Subsequent treatment at 1100°C and 3 GPa for one hour increased Tc(onset) to ∼35K.


2002 ◽  
Vol 35 (5) ◽  
pp. 577-580 ◽  
Author(s):  
Zein Heiba ◽  
Hasan Okuyucu ◽  
Y. S. Hascicek

Nanosized polycrystalline samples of (Er1−uGdu)2O3(0 ≤u≤ 1.0) were synthesized by a sol–gel technique. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofu. The Er3+and Gd3+ions were randomly distributed over two cationic sites, 8band 24d, in the space groupIa\bar{3} (206) in all refined structures. The lattice parameter was found to vary non-linearly with the composition (u). The average microstrain and average crystallite size have been calculated from the Williamson–Hall plots for each sample. The average size ranges from 50 to 70 nm, and the microstrain from 0.4 to 1.7%.


Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 227 ◽  
Author(s):  
Zrinka Švagelj ◽  
Vilko Mandić ◽  
Lidija Ćurković ◽  
Martina Biošić ◽  
Irena Žmak ◽  
...  

In the present work, alumina (Al2O3) foam was prepared by the replica method where a polyurethane (PU) foam (30 pores per inch (ppi)) template was impregnated with a 60 wt.% Al2O3 suspension. Sintered Al2O3 foam was used as substrate for the deposition of sol-gel derived titania (TiO2) film using dip coating. For the preparation of TiO2 sol, titanium(IV) isopropoxide (Ti-iPrOH) was used as the precursor. The common problem of qualification and quantification of a crystalline coating on a highly porous 3D substrate with an uneven surface was addressed using a combination of different structural characterization methods. Using Powder X-ray Diffraction (PXRD) and synchrotron Grazing Incidence X-ray Diffraction (GIXRD) on bulk and powdered Al2O3 foam and TiO2-coated Al2O3 foam samples, it was determined Al2O3 foam crystallizes to corundum and coating to anatase, which was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR). Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed the structural and microstructural properties of the substrate and coating. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) were used to clarify the evolution of the porous microstructure. The Al2O3-TiO2 composite was evaluated as a photocatalyst candidate for the degradation of the micropollutant medication memantine. The degradation rate was monitored using a light-emitting diode (LED) lamp operating at electromagnetic (EM) wavelength of 365 nm. The photocatalytic activity of sol-gel-derived TiO2 film immobilized on the Al2O3 foam was compared with commercially available TiO2 nanoparticles, P25-Degussa, in the form of a suspension. The levels of memantine were monitored by High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS/MS). The efficiency and rate of the memantine photodegradation by suspended TiO2 nanoparticles is higher than the TiO2-coated Al2O3 foam. But, from the practical point of view, TiO2-coated Al2O3 foam is more appropriate as a valuable photocatalytic composite material.


Sign in / Sign up

Export Citation Format

Share Document