An-Najah Staff

Kinetic studies for the non-isothermal decomposition of un-irradiated and γ-irradiated ruthenium(III) acetylacetonate in air were carried out. The results show that the 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 un-irradiated Ru(acac)3. For γ -irradiated Ru(acac)3 with 102 KGy total γ-ray dose, 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 is shown to be non-isothermal, using both model-fitting and model-free approaches. Infrared (IR) spectroscopy and X-ray powder diffraction techniques were employed to follow the chemical composition of the solid residue obtained at different temperatures.

Kinetic studies for the non-isothermal decomposition of unirradiated and γ irradiated silver acetate with 103 kGy total γ-ray doses were carried out in air. The results showed that the decomposition proceeds in one major step in the temperature range of (180–270 °C) with the formation of Ag2O as solid residue. The non-isothermal data for un irradiated and γ-irradiated silver acetate were analyzed using Flynn-Wall-Ozawa (FWO) and nonlinear Vyazovkin (VYZ) iso-conversional methods. These free models on the investigated data showed a systematic dependence of Ea on a indicating a simple decomposition process. No significant changes in the thermal decomposition behavior of silver acetate were recorded as a result of γ-irradiation. Calcinations of γ-irradiated silver acetate (CH3COOAg) at 200 °C for 2 hours only led to the formation of pure Ag2O mono-dispersed nanoparticles. X-ray diffraction, FTIR and SEM techniques were employed for characterization of the synthesized nanoparticles.

Isothermal decomposition of unirradiated and γ-irradiated gallium acetylacetonate Ga(acac)3 with 103 kGy total γ-ray dose was carried out in static air. The isothermal operating temperatures were 160, 170, 180 and 190 C. The kinetics of decomposition were followed using both model-fitting and model-free approaches. The results of model fitting application on the investigated data showed that the decomposition behaviour was best described by phase-boundary controlled reaction (R2). Kinetic parameters of the decomposition process were calculated and evaluated. Analysis of the data using model free approach signifies the dependency of Ea on extent of conversion (α). Pre-γ-irradiation of gallium acetylacetonate Ga(acac)3 with 103 kGy total γ-ray dose has almost no effect on the kinetic parameters.