Synthesis and characterization of reduced transition metal oxides and nanophase metals with hydrazine in aqueous solution

Gui, Zhilun; Fan, Ren‐Hao; Mo, W. Q.; Chen, Xianhui; Yang, Ling; Hu, Yuan

doi:10.1016/s0025-5408(02)00983-2

Cited by 51 publications

(23 citation statements)

References 22 publications

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“…1(a)) revealed that only V 2 O 4 ・2H 2 O phase with a layered structure [JCPDS 13-0346] was present in the product. This result is not consistent with that described by Gui et al, 8) in which only amorphous products appeared, but the reason was unknown. For samples obtained by keeping the suspension at 95°C for 4 d, the crystallinity of the precipitates became better.…”

Section: Results and Discussion 31 Effects Of Solution Conditions Oncontrasting

confidence: 99%

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Bai

Gao

et al. 2008

J. Ceram. Soc. Japan

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Synthesis of well crystallized rod-shaped V 2 O 4 ・2H 2 O powders of 100 nm in width in an aqueous solution containing NH 4 VO 3 and N 2 H 4 ・H 2 O under atmospheric pressure had been investigated. The optimal conditions for atmospherically hot-water treatment at 95°C were found to be as follows: pH 2.5-3.5 and an appropriate amount of N 2 H 4 ・H 2 O. How the solution conditions affect the crystal structures and morphologies of the products is discussed. At pH＜2.5, no precipitates formed. At pH 4.0-4.5, V 10 O 24 ・12H 2 O would generally be obtained if N 2 H 4 ・H 2 O was excessive. It was independent of reduction of NH 4 VO 3 solution to tetravalent solids on the dosage of reducing agent N 2 H 4 ・H 2 O. The morphologies of the V 2 O 4 ・2H 2 O had no obvious relationship with the pH and the dosage of N 2 H 4 ・H 2 O. It seems that before treated at 95°C the products were sheet-shaped, and then cleaved along specific crystalline directions after treated, forming rod bunches. The stability of V 2 O 4 ・2H 2 O in acid solution and in air was also investigated. The results showed that V 2 O 4 ・2H 2 O was unstable in air and could undergo oxidization to be a quasiamorphous rod-shaped V 10 O 24 ・12H 2 O, especially at high pH, with excessive N 2 H 4 ・H 2 O, drying at 150°C in flowing air, and/or being exposed to air for several days.

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Section: Results and Discussion 31 Effects Of Solution Conditions Oncontrasting

confidence: 99%

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Bai

Gao

et al. 2008

J. Ceram. Soc. Japan

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“…Recently, Gui et al reported on the reduction of firstrow [3d] transition-metal complexes in aqueous hydrazine solution. 11 A number of studies were performed to synthesize noble metal particles of different elements starting from micellization of polymeric templates in aqueous medium. 12,13 The important key factor of this method is to synthesize a soluble copolymer making micellar 13 or dendritic 12 structures which have enough space at the core for smaller metal salt molecules.…”

Section: Introductionmentioning

confidence: 99%

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Demir¹,

Gülgün²,

Menceloǵlu³

et al. 2004

Macromolecules

284

172

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Catalytic palladium (Pd) nanoparticles on electrospun copolymers of acrylonitrile and acrylic acid (PAN-AA) mats were produced via reduction of PdCl2 with hydrazine. Fiber mats were electrospun from homogeneous solutions of PAN-AA and PdCl2 in dimethylformamide (DMF). Pd cations were reduced to Pd metals when fiber mats were treated in an aqueous hydrazine solution at room temperature. Pd atoms nucleate and form small crystallites whose sizes were estimated from the peak broadening of X-ray diffraction peaks. Two to four crystallites adhere together and form agglomerates. Agglomerate sizes and fiber diameters were determined by scanning and transmission electron microscopy. Spherical Pd nanoparticles were dispersed homogeneously on the electrospun nanofibers. The effects of copolymer composition and amount of PdCl 2 on particle size were investigated. Pd particle size mainly depends on the amount of acrylic acid functional groups and PdCl2 concentration in the spinning solution. Increasing acrylic acid concentration on polymer chains leads to larger Pd nanoparticles. In addition, Pd particle size becomes larger with increasing PdCl 2 concentration in the spinning solution. Hence, it is possible to tune the number density and the size of metal nanoparticles. The catalytic activity of the Pd nanoparticles in electrospun mats was determined by selective hydrogenation of dehydrolinalool (3,7-dimethyloct-6-ene-1-yne-3-ol, DHL) in toluene at 90°C. Electrospun fibers with Pd particles have 4.5 times higher catalytic activity than the current Pd/Al 2O3 catalyst.

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“…Hydroxylamine was used to produce transition metal oxides such as Fe 3 O 4 , VO 2 and MoO 2 at relatively low temperature by Goodenough et al [34][35]. Transition nanoscale metal oxides were synthesized with hydrazine as reducing agent [36]. Recently, many efforts to fabricate different nanoparticles have been focused on using greener methods such as aqueous ascorbic acid as the reducing agent [37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

A new reduction route for the synthesis of nanoscale metals and metal oxides with ascorbic acid at low temperature

Khorasani-Motlagh

Noroozifar

Shahroosvand

2010

JICS

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Reduction of the transition metal complexes in aqueous solution has been investigated systematically by ascorbic acid as the reducing agent without the assistance of any surfactant. Nanoparticles of Į-Mn 2 O 3 , Ag and Cu were synthesized directly through aqueous phase reduction at room temperature. Nanoscale metal oxides such as Co 3 O 4 , Į-Fe 2 O 3 and MoO 2 were obtained through ascorbic acid reduction in alkali medium at 40ÛC. All the products were characterized on their structure and micro-morphology by the X-ray diffraction (XRD) and atomic force microscopy (AFM). The particle size of metal and metal oxides was about 10-50 nm. The reaction details and features were described and discussed.

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Synthesis and characterization of reduced transition metal oxides and nanophase metals with hydrazine in aqueous solution

Cited by 51 publications

References 22 publications

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

A new reduction route for the synthesis of nanoscale metals and metal oxides with ascorbic acid at low temperature

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Synthesis and characterization of reduced transition metal oxides and nanophase metals with hydrazine in aqueous solution

Cited by 51 publications

References 22 publications

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Synthesis and atmospheric instability of well crystallized rod-shaped V2O4 2H2O powders prepared in an aqueous solution

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl2 Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

A new reduction route for the synthesis of nanoscale metals and metal oxides with ascorbic acid at low temperature

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Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity