Journal ArticleDOI
Structural and magnetic properties of polymer-stabilized tetragonal Ni nanoparticles
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In this article, the effect of polyvinyl alcohol (PVA) molecules on Ni-NPs was investigated and it was found that both uncoated and PVA-coated NiNPs exhibit a tetragonal crystal structure, i.e. different from the cubic structure of bulk Ni.Abstract:
Ni nanoparticles (Ni-NPs), with diameter (D) ranging 5–30 nm, were synthesized by reducing nickel chloride with NaBH4 in the presence of polymer molecules of poly-vinyl alcohol (PVA) in cold water. Nickel chloride was dispersed in the PVA molecules which stabilized the resulting Ni-NPs. Experiments were carried out with and without PVA to elucidate the effect of PVA molecules on the structural and magnetic properties of Ni-NPs. It was found that both uncoated (uc) and PVA-coated (pc) Ni-NPs exhibit a tetragonal (t) crystal structure, i.e. different from the cubic (fcc) structure of bulk nickel. pc Ni-NPs (paramagnetic in nature) converted to fcc Ni (spherical shape, D ∼ 12 nm) on annealing at 573 K in air, exhibiting a saturation magnetization M s = 20.5 emu/g, squareness ratio M r /M s = 0.48 and coercivity H c = 248 Oe, which is higher than the bulk Ni (0.7 Oe). uc Ni-NPs showed little improvement in M s and H c on air annealing. The core–shell structure resulted in a high H c value in stable pc Ni-NPs ...read more
Citations
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Size dependence of the magnetic properties of Ni nanoparticles prepared by thermal decomposition method
TL;DR: A theoretical model is proposed to explain the size dependence of TC and it is revealed that with increase of surface-to-volume ratio of Ni nanoparticles due to decrease of particle size, there is increase of the percentage of magnetically inactive layer.
Journal ArticleDOI
Deactivation of Ni/TiO2 catalyst in the hydrogenation of nitrobenzene in water and improvement in its stability by coating a layer of hydrophobic carbon
TL;DR: In this paper, a hydrophobic carbon layer was successfully coated on Ni/TiO2 catalysts by a hydrothermal method and they presented higher reactivity and improved stability in the present aqueous reaction system; nickel hydroxide was not detected on the used and water treated carbon-coated Ni/ TiO2 samples.
Journal ArticleDOI
Promoting Ni(II) catalysis with plasmonic antennas
Pengfei Han,Pengfei Han,Tana Tana,Qi Xiao,Sarina Sarina,Eric R. Waclawik,Daniel E. Gómez,Daniel E. Gómez,Huaiyong Zhu +8 more
TL;DR: In this article, the authors show that reactant molecules can be significantly concentrated at the active sites simply by light and thus increase the chance of activation, and the merging of plasmonic antenna and metal cationic catalysis will be an inspiring strategy for designing efficient photocatalytic systems.
Journal ArticleDOI
Structural, optical and magnetic properties of pure and rare earth-doped NiO nanoparticles
TL;DR: In this paper, a series of rare earth element (RE) (Er, Sm, Gd, Pr and Y)-doped NiO nanoparticles (NPs) were fabricated by co-precipitation method in the presence of polyvinyl alcohol as a capping agent.
Journal ArticleDOI
Nickel Colloid Nanoparticles: Synthesis, Characterization, and Magnetic Properties
TL;DR: In this article, the reduction of metal salt (NiCl2·6H2O) in the presence of low concentration of hydrazine hydrate using a commercial copolymer (latex) as both reducing and stabilizing agents.
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