An advanced reaction model determination methodology in solid-state kinetics based on Arrhenius parameters variation

Abstract

The variation in the activation energy with the conversion degree of reaction is generally due to the overlapping of parallel or consecutive reactions, and the solution of the problem must imply the deconvolution of the overlapping reaction rather than fitting the experimental curve by assuming variable kinetic parameters. Furthermore, determination of the most probable reaction mechanism model(s) in complicated multi-step reactions kinetics is confronting with the activation energy and the pre-exponential factor variations, as the well-known methods of the thermal analysis are not suitable for determination of the reaction mechanism model(s). To solve this problem, an advanced method for determination of reaction mechanism model based on distributed activation energy model and Arrhenius parameters variation is put forward. This method appears to accurately simulate single-step as well as multi-step reactions kinetics. The proposed method is experimentally verified by taking an experimental example of non-isothermal decomposition kinetics of Cu4SO4(OH)6 for the tenorite (CuO) nanoparticles preparation. The results are compared with the iterative procedure and the Arshad and Maaroufi method and effectively interpreted.