scholarly journals Preparation of Ta2O5 nanoparticles by using cathode glow discharge electrolysis

2021 ◽  
Author(s):  
Quan-fang Lu ◽  
Juan-long Li ◽  
Jie Yu ◽  
Li-juan Cui ◽  
Bo Wang ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Wide Band ◽  
Discharge Voltage ◽  
Tantalum Foil ◽  
Ammonium Bromide ◽  
Wide Band Gap ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Ft Ir ◽  
Glow Discharge Electrolysis ◽  
Cetyltrimethyl Ammonium

Abstract Tantalum pentoxide nanoparticles (Ta2O5 NPs) were fabricated by cathode glow discharge electrolysis (CGDE) generated between a needle-like platinum wire cathode and a tantalum foil anode in 6 g L−1 Na2SO4 electrolyte solution containing 5 mL hydrofluoric acid (HF) and 0.075 g cetyltrimethyl ammonium bromide (CTAB). The chemical structure, composition and morphology of the obtained powder were analyzed by using XRD, FT-IR, SEM/EDS, XPS and UV-vis DRS. The results found that Ta2O5 NPs with orthorhombic structure and wide band gap (3.6 eV) are successfully fabricated at 500 V discharge voltage in about 3 h. CTAB as a stabilizing agent can reduce the agglomeration due to forming CTA+ and attaching the surface of the synthetic products. A possible preparation mechanism of Ta2O5 NPs is proposed. Firstly, the tantalum foil anode is oxidized to form a compact Ta2O5 layer. Then, Ta2O5 surface is etched to form soluble [TaF7]2− complexes in the presence of HF. After that, soluble [TaF7]2− complexes can react with H2O to form Ta(OH)5. Finally, Ta(OH)5 is further converted to Ta2O5 from plasma-liquid interface into solution.

Preparation of OMMT and Light-Colored and Transparent PI/OMMT Hybrid Composite Films

2013 ◽  
Vol 634-638 ◽  
pp. 1985-1989
Author(s):  
Yun Hua Lu ◽  
Zhi Zhi Hu ◽  
Guo Yong Xiao ◽  
Yan Dong ◽  
Hai Jun Chi
Keyword(s):  
Hybrid Composite ◽  
Hybrid Composites ◽  
Composite Films ◽  
Amic Acid ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Aromatic Diamines ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Ft Ir ◽  
Cetyltrimethyl Ammonium

The organo-modified montmorillonite (OMMT) was prepared from Na+montmorillonite (Na+MMT) by cation exchange with cetyltrimethyl ammonium bromide (CTMAB). The light-colored and transparent polyimide (PI) and OMMT hybrid composite films from the solution of poly(amic acid)(PAA) and various amounts (0.25, 0.50, 0.75, 1.00wt%) of OMMT in N, N-dimethylacetamide (DMAc) were prepared. The PAA was synthesized from the reaction of the alicyclic dianhydrides 1,2,3,4-cyclobutanetrtracarboxylic dianhydride (CBDA) and fluorinated aromatic diamines 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB). The OMMT and PI/OMMT hybrid composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis transmission spectra and solubility testing. The experimental results showed that the OMMT exhibited a 2.12nm d-spacing value. These obtained PI/OMMT hybrid composites were soluble in typical imide type polar solvent. As the OMMT contents are increased, the transparency of the PI/OMMT hybrid composite films is sacrificed slightly. These PI/OMMT hybrid films are good candidates for potential solar cell flexible substrates.

A Facile One-Step Hydrothermal Synthesis of Graphene/CeO2 Nanocomposite and its Catalytic Properties

2013 ◽  
Vol 747 ◽  
pp. 242-245 ◽  
Author(s):  
Manish Srivastava ◽  
Ashok Kumar Das ◽  
Partha Khanra ◽  
Nam Hoon Kim ◽  
Joong Hee Lee
Keyword(s):  
Catalytic Activity ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Xrd Pattern ◽  
Transmission Electron ◽  
One Step ◽  
Ft Ir ◽  
Cetyltrimethyl Ammonium

Graphene/CeO2 nanocomposite has been successfully prepared by directly growing CeO2 nanoparticles on graphene sheets via in-situ reduction of graphene oxide containing the metal precursor. The presence of cetyltrimethyl ammonium bromide (CTAB) results the formation of CeO2 nanoparticles with a narrow size distribution. The structural, morphological, particles size and optical properties of the synthesized products were investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and UVvis absorbance spectroscopy, respectively. The XRD pattern shows that graphene/CeO2 nanocomposite is highly crystalline in nature. Growth of CeO2 nanoparticles with size in range of 5-18 nm on the graphene sheet were observed by TEM measurement. Optical energy band gap was calculated to be ~3.30 eV corresponding to direct transition. The catalytic activity of the synthesized nanocomposite was investigated taking hydrazine hydrate as a model system. Significant enhancement in the peak current with respect to CeO2 was observed on graphene/CeO2 nanocomposite-based electrode demonstrating the higher catalytic activity of graphene/CeO2 nanocomposite-based electrode.

V2O5-Polyaniline Nanocomposite as a Catalyst for Heterogeneous Ozonolysis of Oleic Acid

2011 ◽  
Vol 364 ◽  
pp. 217-221 ◽  
Author(s):  
Khadijeh Beigom Ghoreishi ◽  
Asim Nilofar ◽  
Mohd Ambar Yarmo
Keyword(s):  
Oleic Acid ◽  
Ammonium Bromide ◽  
Ozone Absorption ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Weight Percentage ◽  
Acid Cleavage ◽  
Micelle Solution ◽  
Ft Ir ◽  
Cetyltrimethyl Ammonium ◽  
Sulfate Hydrate

Nanocomposite V2O5-polyaniline (pani) is produced via micelle solution by using cationic surfactant (cetyltrimethyl ammonium bromide, CTAB) and vanadyl sulfate hydrate as a precursor. TEM results showed that V2O5-pani nanocomposite with 20-70 nm in size is formed via micelle solution. This nanocomposite as catalyst is utilized the production of azelaic acid (AA) and pelargonic acid (PA) from oleic acid cleavage in solvent free medium. Various loading percentages of V2O5in Pani are considered and their differences in activity and selectivity are also evaluated. According to GC analysis, results showed that nanocomposite as catalyst is two times more selective to AA compare to bulk V2O5(53%, 28% respectively). Also this nanocomposite indicated higher selectivity to AA and PA rather than nanoV2O5(53% compare to 32%) It is showed that in higher weight percentage of V2O5to polyaniline, the conversion of OA to two main products, AA and PA in ozonolysis reaction ( according to Criegee mechanism ) is higher. Ozone absorption of OA is monitored by FT-IR and the activity and selectivity of catalyst is monitored by GC-FID.

Scheelite (CaWO4)-type microphosphors: Facile synthesis, structural characterization and photoluminescence properties

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650400 ◽  
Author(s):  
Yuanyuan Han ◽  
Dan Wang ◽  
Danyang Liang ◽  
Shiqi Wang ◽  
Guoxin Lu ◽  
...  
Keyword(s):  
Luminescence Decay ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
Photoluminescence Properties ◽  
Facile Synthesis ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Broad Emission ◽  
Transition Formula ◽  
Cetyltrimethyl Ammonium ◽  
Uv Excitation

Scheelite (CaWO4)-type microphosphors were synthesized by the precipitation method assisted with cetyltrimethyl ammonium bromide (CTAB). All compounds crystallized in the tetragonal structure with space group [Formula: see text] (No. 88). FE-SEM micrographs illustrate the spherical-like morphologies and rough surface. PL spectra indicate the broad emission peak maximum at 613 nm under UV excitation. Luminescence decay curves monitored by [Formula: see text] transition ([Formula: see text] nm) of Eu[Formula: see text] in doped CaWO4 are presented, the curves exhibit a single-exponential feature and the lifetime for doped CaWO4 is 0.61 ms.

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