Dendritic nickel agglomerates composed of nickel nanoparticles have been synthesized through one-step electro-deposition using NiCl2·6H2O as precursor and ethanol as solvent. Analytical results by X-ray diffraction (XRD) and selected area electron diffraction (SEAD) indicate that the as-prepared products belong to face-centered cubic structure of nickel nanoparticles with high purity. Morphological observation reveals that the deposits are mainly dendritic containing nanoparticles. The magnetic properties of deposits have also been measured at room temperature and the results show that the saturation magnetization increases and the coercivity decreases as increasing the NiCl2·6H2O concentration.
Composite electrode of iron oxide Fe2O3 and carbon nanotube has been prepared for the negative electrode of lithium batteries with ionic liquid electrolyte. The composite containing 29 wt% of Fe2O3 exhibits as large as 300 mAh g−1 of specific capacity in the electrolyte based on 1-ethyl-3-methyl imidazolium bis(fluorosulfonyl)amide (EMIFSA) as well as in a conventional alkylcarbonate electrolyte. When the loading of Fe2O3 is at as low extent as 29 wt%, cross-linking morphology created by carbon nanotube substrate provides nano-spaces in the composite and assures mass transfer beneath electrode and thus rate capability even in viscous ionic liquid electrolyte.
Highly-dispersed Li3V1.8Al0.2(PO4)3 nanoparticles which are directly impregnated onto the surface of multi-walled carbon nanotubes (MWCNT) were successfully synthesized via a unique two-step process using an ultracentrifugation at 75,000 g. The synthetic procedure of the Li3V1.8Al0.2(PO4)3/MWCNT composite involves the following two steps: i) precipitation of V1.8Al0.2O3 (10–100 nm) nanoparticles on the surface of MWCNT, and ii) the subsequent transformation of the V1.8Al0.2O3 into the Li3V1.8Al0.2(PO4)3 nanoparticles without any change of their shape and dimensions. The 10% of Al-doping brought out an increase in the discharge capacity from 119 to 124 mAh g−1 per Li3V2−xAlx(PO4)3, which corresponds to a 14% increase of the Li3V2−xAlx(PO4)3 utilization ratio. The Al-doping also reduced its electric resistance by 26%. The Li3V1.8Al0.2(PO4)3/MWCNT with such an efficient electron transport can deliver excellent electrochemical performances ever attained to date; capacity density of 85 mA h g−1 at a high discharge rate of 480C and stable cycle performance over 10,000 cycles at 10C rate with 85% retention of the initial capacity.
Catalytic coatings comprising a mixture of IrO2 and Ta2O5 were prepared at 50–80 mol% Ir by thermal decomposition at 470°C, and the crystallographic structures and surface morphologies were investigated. XRD analysis and high-resolution SEM observation using low accelerated incident beam revealed that decreasing Ir ratio made a phase transition of IrO2 from crystalline to partly amorphous, and nano IrO2 particles of 10 nm or less and nano chains made of them, which were uniformly dispersed on the flat area of the coating, were generated at 50–60 mol% Ir. The relationship between nano-scale surface morphology of the coating and electrocatalysis for oxygen evolution in H2SO4 solutions was also investigated. The active surface area and oxygen evolution current increased with reducing Ir ratio. The electrocatalysis of the IrO2-Ta2O5 coatings for oxygen evolution is possible to be attributed to nano IrO2 particles.
N′-(4-hydroxy-3-methoxybenzylidene)-2-(5-p-tolyl-1,3,4-thiadiazol-2-ylthio) acetohydrazide (HMTH) was studied as a novel corrosion inhibitor for carbon steel in hydrochloric acid solution by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), cyclic voltammetry (CV) techniques and Quantum chemical calculation. The surface morphology of carbon steel in HCl solution in the absence and presence of HMTH was investigated by scanning electron microscopy (SEM). The mechanism of adsorption was determined from Fourier transform infrared spectroscopy (FTIR) and the potential of zero charge (Epzc). HMTH was found to be an effective corrosion inhibitor by forming a stable adsorption layer on carbon steel.
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