Ni-Co bimetallic nanoparticles (NPs) have been synthesized via reduction of Ni and Co hydroxides by hydrazine in water / ethylene glycol solutions. It was found that the particle size polydispersity obtained chemically homogeneous NPs decrease with a decreasing to 50 at.% content reaction mixture. A different trend observed for Ni25Co75 related formation Ni- Co-rich particles. Ni-Co-NPs were tested as catalysts hydrolysis alkaline solutions NaBH4, highest rate hydrogen generation Ni50Co50....

Nickel nanoparticles (NiNPs) were synthesized via the reducing of nickel ions with hydra-zine in an alkaline solution ethylene glycol under different conditions. It was found that conditions homogeneous nucleation obtained NiNPs are irregular shape and form continuous linear agglomerates a length 1.5–3.5 micrometres, contrary, heterogeneous monodisperse nanopowders average particles diameter 180±40 nm formed. used as fillers for preparation electroconductive nickel-containing polymer...

ABSTRACT The formation of sodium citrate stabilized spherical silver nanoparticles synthesized by homogeneous nucleation in aqua solutions was monitored the method direct potentiometry. It observed that kinetic curve Ag + ions reduction can be described Finke–Watzky (FW) autocatalytic two–step mechanism case a large excess hydrazine and NaOH. To expand FW minimalistic model, impact starting concentrations reagents on kinetics synthesis studied. determined stage is limited process reduction,...

The electrochemical method of synthesis silver nanoparticles (AgNPs) using ‘sacrificial’ anode as a source Ag + , microbial origin surfactant (rhamnolipid, RL) stabiliser AgNPs and electric current reducer is presented. Using cyclic voltammetry it was determined that RL concentration temperature are the main factors influencing rate anodic dissolution cathodic reduction formed complex [AgRL] . Increasing leads to increasing currents indicate increase formation. With from 40 60°C values 1.5...

The paper shows the effectiveness of a “green” synthesis silver nanoparticles (AgNPs) in sodium polyacrylate (NaPA) solutions by sonoelectrochemical method using sacrificial anodes. Using cyclic voltammetry ultrasonic field range E from 1.0 to -1.0 V, temperature and NaPA concentration are main parameters influencing rate size AgNPs. As these increase, nanoparticle increases. According TEM studies, with increasing decreasing concentration, there is tendency increase However, all cases, AgNPs...

Abstract The kinetics of formation silver nanoparticles consisting nearly 300 metal atoms is investigated, which were prepared by reduction nitrate with hydrazine in ethylene glycol at 25°C without any stabilizer other than the solvent. resulting sigmoidal kinetic curves are analyzed using 1997 Finke–Watzky two‐step mechanism slow continuous nucleation subsequent fast autocatalytic surface growth. homogeneous was assumption about stepwise adjunction precursor and quasi steady‐state...

The process of the formation silver nanoparticles (AgNPs) via method galvanic replacement (GR) Ag+ with aluminum powder in sodium polyacrylate (NaPA) solutions ultrasonic (US) field has been studied. It was observed, that yellow colloidal stabilized AgNPs absorption maximum at ∼ 410 nm were obtained under application US power by 20 W and frequency kHz wide range AgNO3 NaPA concentrations (0.1 – 0.5 mM 5.0 g/L respectively) 25 0C. shown, GR occurs without significant induction period. Using...

Abstract No satisfactory quantitative relationships exist between polymer swelling parameters and some distinct physical‐chemical of organic solvents producing this swelling. Such can only be obtained by means linear multiparameter equations, which take into account the energy needed for cavity formation in also solvation effects. The advantages such an approach are supported examples generalization experimental data many polymers coals. Copyright © 2005 John Wiley & Sons, Ltd.

Heterogeneous reaction of reduction freshly prepared nickel hydroxide by hydrazine hydrate in water/ethylene glycol solutions have been investigated. The effect the initial concentration and temperature on duration induction period total zero formal orders nucleation growth processes for were found as well observed that activation energies these are close. size composition formed nanoparticles investigated using scanning electron microscopy. It was obtained particles characterized...

Ni(Co)/Pd nanosized ternary composite materials have been synthesized by the galvanic replacement method. The structure and phase composition of obtained nanostructures were investigated using SEM, EDX X–ray powder diffraction. catalytic activity polymetallic nanoparticles was studied example reduction reaction p–nitrophenol with NaBH4 solution. It found that in all cases process presence as a catalyst is described first-order kinetic equation for p–nitrophenol. based on nickel (Ni) varied...

Catalytic systems based on nickel nanoparticles (NiNPs) can be used to reduce the nitroaromatic compounds with sodium borohydride, obtain synthesis gas from reducing raw materials, etc. The mechanism of catalytic action in such processes is similar Raney nickel, however, nanosize particles makes it possible create a much wider range due use various carriers. Research into NiNPs hydrogen generation deserves special attention. In particular, known that are an effective catalyst for...

Abstract Using electron spin resonance spectroscopy, we have studied the kinetics of bimolecular decay methacrylic macroradicals in networked and unnetworked polymeric matrices. We determined that macroradical entire range temperatures (20–70°C) is definitely ordered to a second‐order kinetic reaction equation. estimated activation parameters process. Smolukhovsky's Einstein's equations fractal dependence conformation radius on its polymerization degree, obtained an equation for constant...

Air stable nickel nanopowders have been synthesized via the reduction of as-prepared Ni(OH) 2 by hydrazine in water/ethylene glycol solutions under heterogeneous nucleation conditions at70 °C. The resulting product is a powder black color; yield all cases exceeded 95%. influence ratio on reaction proceeding and size distribution obtained nanoparticles investigated. Using method electron microscopy it was found that particles are mainly globular. It established mean diameter polydispersity...

Silver nanoparticles stabilized by rhamnolipid, which was separated from the supernatant of fluid genus Pseudomonas sp . PS-17, were synthesized. Using TEM it found that mean size obtained AgNPs is 2.6 nm and does not depend on initial concentration Ag + The kinetics formation studied using UV-vis spectroscopy. It observed in all cases kinetic curves are sigmoidal shape characterized well-notable induction period confirms homogeneous nucleation as well may indicate absence agglomeration...

Silver nanoparticles (AgNPs) have been synthesized by “green syn­thesis” using the silver nitrate as precursor and surface-active rhamnolipid biocomp­lex – product of microbial synthesis strain Pseudomonas sp. PS-17 reducing agent stabilizer. Kinetics AgNPs formation was monitored UV/vis spectro­metry. It found that reaction is carried out without induction period indi­cating heterogeneous nature nucleation. Using transmission ele­ctron microscopy it obtained sol consisted small...