non-isothermal decomposition

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Kinetic Studies For The Non-Isothermal Decomposition Of Un-Irradiated and γ-Irradiated Ruthenium(III) Acetylacetonate

Journal Title, Volume, Page: 
Radiation Effects and Defects in Solids: Incorporating Plasma Science and Plasma Technology Volume 164, Issue 4, 2009
Year of Publication: 
2009
Authors: 
R. M. Mahfouz
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
Sh. A. Al-Ahmari
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
I. Kh. Warad
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
Current Affiliation: 
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
S. I. Al-Resayes
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
M. R.H. Siddiqui
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
K. R. Raslan
Natural Science (Mathematics), Community College of Science, King Saud University, Riyadh, Saudi Arabia
A. M. Al-Otaibi
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh-11451, Saudi Arabia
Preferred Abstract (Original): 
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.
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Model Free Approach for Non-Isothermal Decomposition of Un-Irradiated and g-Irradiated Silver Acetate: New Route for Synthesis of Ag2O Nanoparticles

Journal Title, Volume, Page: 
Int. J. Mol. Sci. 2010, 11(9), 3600-3609; doi:10.3390/ijms11093600
Year of Publication: 
2010
Authors: 
Mohammed Rafiq H. Siddiqui
Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh-11451, Saudi Arabia
Saad Alshehri
Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh-11451, Saudi Arabia
Ismail Kh. Warad
Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh-11451, Saudi Arabia
Current Affiliation: 
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Naser M. Abd El-Salam
Department of Natural Sciences, Riyadh Community College, King Saud University, P. O. Box 28095, Riyadh-11437, Saudi Arabia
Refaat M. Mahfouz
Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh-11451, Saudi Arabia
Preferred Abstract (Original): 
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.
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