Non‐Isothermal Decomposition Kinetics of Hafnium and Zirconyl Hydrogentellurates

ABSTRACT The thermal characteristics of zirconyl and hafnium hydrogentellurates, ZrO(HTeO 4 ) 2 × 4H 2 O (ZrOTe) and Hf(HTeO 4 ) 4 × 8H 2 O (HfTe), were investigated via non‐isothermal decomposition kinetics in this paper for the first time. Important kinetic parameters such as activation energy ( E A ), pre‐exponential factor ( A ) and g ( α ) function were determined using Coats‐Redfern integral method. The latter was verified by means of z ( α ) master plots. In addition, plausible decomposition mechanisms for the title compounds were offered. Based on the E A values, less thermal stability for ZrOTe (633.69 kJ/mol) with respect to HfTe (872.24 kJ/mol) was observed. Thermodynamic functions (Δ S ≠ , Δ H ≠ , and Δ G ≠ ) of the activated complexes generated during the thermal decomposition steps were studied as well. A high positive Δ H ≠ value (855.70 kJ/mol) for the thermal decomposition of HfTe indicated formation of high‐ordered activated complexes. In contrast, lower Δ H ≠ (612.50 kJ/mol) for ZrOTe suggested easier formation the transition states in that case.