We have studied the effect of oxygen on the time-dependent bifurcations of transient oscillations in the Belousov-Zhabotinsky oscillating chemical reaction in a closed system. Experiments show that oscillations disappear through different bifurcations depending on the oxygen concentration in gas phase above the reaction solution. Oscillations disappear through the time-delayed Hopf bifurcation at low oxygen concentrations, whereas at high oxygen concentrations they disappear through the time-dependent SNIPER (saddle-node infinite period) bifurcation. We propose a kinetic scheme that describes the effects observed in experiments. Good agreement between the experimental data and simulations is obtained.

Monodisperse platinum nanoparticles with controlled size were synthesized by polyol synthesis and supported on γ-Al 2 O 3 , SiO 2 and carbon nanotubes (CNT) by the colloid deposition method. The average size of Pt nanoparticles in colloidal solutions and on supports was determined by TEM images and from XRD patterns. The size of Pt nanoparticles supported on SiO 2 and CNT determined from XRD patterns is in a good agreement with size obtained from the TEM analyses. There were shown that no agglomeration and size changing of Pt nanoparticles on these supports were observed. All these findings illustrate that the method of colloid deposition allows one to obtain catalyst with monodisperse platinum nanoparticles of controlled size deposited on different supports without changing the nanoparticle's size and morphology.

Core-shell nanoparticles Fe@Fe₃O₄ supported on activated carbon (AC) and carbon nanotubes (CNTs) have been studied by H₂ temperature-programmed reduction (TPR). Nanoparticles with size of 6.5 nm were synthesized by iron(II) oleate thermal decomposition and were supported on activated carbon and carbon nanotubes by colloid deposition method. The nanoparticles Fe@Fe₃O₄ are characterized by TEM and IR. Reduction of nanoparticles on AC starts at 140?C, whereas reduction of nanoparticles on CNTs starts at 200?C. Moreover, gasification of CNTs with methane releasing starts at 450?C, whereas gasification of AC is negligible at temperatures up to 800?C. All these findings illustrate a strong difference in the interaction between nanoparticles and the support material for AC and CNTs

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