Application of simplified version of advanced isoconversional procedure in non-isothermal kinetic study

The single phase NH 4 Co 0.9 Zn 0.1 PO 4 ·H 2 O was prepared via solid-state reaction at 80 °C. Based on a simplified version of advanced isoconversional procedure, the values of activation energy E α associated with the first, second, and third stages of the thermal decomposition of NH 4 Co 0.9 Zn 0.1 PO 4 ·H 2 O were obtained, which demonstrates that the third stage is a kinetically complex process, and the first and second stages are single-step kinetic processes and can be described by a unique kinetic triplet [ E α , A , and g (α)]. The most probable reaction mechanisms of the first two stages were estimated by the comparison between experimental plots and modeled results. The values of pre-exponential factor A of the two stages were obtained on the basis of E α and the reaction mechanisms. The distributed activation energy model was applied to study the third stage. Besides, some thermodynamic functions of transition state complexes (Δ S ≠ , Δ H ≠ , and Δ G ≠ ) of the two stages were also calculated.