Kinetic Analysis of Thermal Decomposition of Unirradiated and γ-Irradiated Tris(ACEtylacetonato)-Ruthenium(III) [Ru(acac)₃]

Abstract

The thermal decompositions of unirradiated and γ-irradiated Ru(acac)3 were studied in air. The results show that decomposition proceeds in one major step in the temperature range of 150-250°C with the formation of RuO2 as a final solid residue for unirradiated Ru(acac)3. For γ-irradiated Ru(acac)3, with a total γ-ray dose of 102kGy, the decomposition goes eventually to completion with almost 100% decomposition and proceeds in one major step which contains four overlapping decomposition stages in the temperature range of 200 −320°C. The kinetics were followed isothermally and non-isothermally using both model-fitting and model-free approaches. IR spectroscopy and X-ray powder diffraction techniques were employed to follow the chemical composition of the solid residues obtained at different temperatures. In a model-fitting approach, the kinetic triplet, i.e. the apparent activation energy Ea, the pre-exponential factor, ln A, and the reaction model f (α), were analyzed and calculated using straight line plots, and reduced time plots by isothermal measurements. For non-isothermal measurements we have applied the Coats and Redfern, and Kennedy and Clark methods. In the model-free approach, the non-thermal data for both unirradiated and γ-irradiated Ru(acac)3 samples were analyzed using the Flynn-Wall-Ozawa (FWO), Tang (T), and Vyazovkin (Vyz) isoconversional methods. The results of application of model-free and model-fitting approaches to the thermal decompositions of both unirradiated and γ-irradiated Ru(acac)3 were compared and evaluated to deduce the most probable kinetic triplet that describes correctly the thermal behavior of Ru(acac)3. Discussion of the results is preceded by a short review of the models relevant to this study.

Kinetic Studies of Isothermal Decomposition of Unirradiated and Γ-Irradiated Gallium Acetylacetonate: New Route for Synthesis of Gallium Oxide Nanoparticles

“…In continuation of our studies on the thermal decomposition of acetyl acetonate compounds [1,2,17], we report here the results of our studies on the thermal decomposition behaviour of unirradiated and g-irradiated Ga(acac) 3 . This was investigated in static air in order to shed more light on the kinetics of thermal decomposition of Ga(acac) 3 and the role of ionising radiation on the thermal behaviour of Ga(acac) 3 .…”

“…Thermal treatment of inorganic substances has a great synthetic potential as it may convert simple compounds into more complex material, such as ceramics, catalysts and glasses, and could lead to metal or oxide nanoparticles displaying a very narrow size distribution [1]. Many recent studies on the thermal decomposition of inorganic solids have included measurements on samples that were exposed to radiation prior to heating with the aim of investigating the effect of ionising radiation on the kinetics and thermal decomposition behaviour of inorganic compounds [2 -7].…”

Kinetic Analysis for the Non-Isothermal Decomposition of Un-Irradiated and Y-Irradiated Zirconium Acetylacetonate

“…Due to our continued interest in the thermal decomposition behaviour of acetylacetonates, we previously studied the isothermal decomposition of Ru(acac) 3 [9] and have now extended our work to the decomposition of Zr(acac) 4 . In the present work, the thermal decomposition behaviour of un-irradiated and -irradiated Zr(acac) 4 was investigated in air with the aim to (a) examine the kinetics of the non-isothermal decomposition of both un-irradiated and -irradiated Zr(acac) 4 using both a model-free approach and model-fitting approach and to (b) clarify the effects of -irradiation on the thermal decomposition behaviour of Zr(acac) 4 .…”

Kinetic Studies of the Non-Isothermal Decomposition of Unirradiated and Γ-Irradiated Gallium Acetylacetonate

“…The thermal treatment of inorganic substances has much synthetic potential as it may transform simple compounds into advanced materials, such as ceramics, catalysts and glasses and could lead in many cases to metal or oxide nanoparticles displaying a very narrow size distribution [1]. Many recent studies on the thermal decomposition of inorganic solids have included measurements on samples that were exposed to radiation prior to heating with the aim to investigate the effect of ionizing radiation on the kinetics and thermal decomposition behaviour of inorganic compounds [2].…”