Combined kinetic analysis of solid-state reactions:: A powerful tool for the simultaneous determination of kinetic parameters and the kinetic model without previous assumptions on the reaction mechanism
Combined kinetic analysis of solid-state reactions:: A powerful tool for the simultaneous determination of kinetic parameters and the kinetic model without previous assumptions on the reaction mechanism
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DOI：
10.1021/jp064792g
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发表时间：
2006-11-16
影响因子：
2.9
通讯作者：
Sanchez-Jimenez, P. E.
中科院分区：
文献类型：
--
作者：
Perez-Maqueda, L. A.;Criado, J. M.;Sanchez-Jimenez, P. E.
组合动力学分析意味着在任何实验条件下获得的正向固态反应的实验数据代表的同时分析。该分析是基于这样的事实，即当一个固态反应是由一个单一的活化能，preexponetial因子和动力学模型描述，每个实验的T-α-d α/dt三重峰应该适合的一般微分方程独立的实验条件用于记录这样的三重峰。因此，只有正确的动力学模型才能拟合所有的实验数据，得到唯一的活化能和指前因子。然而，该方法的局限性应被考虑;因此，所提出的固态动力学模型是通过假设理想条件（例如独特的颗粒尺寸和形态）来推导的。在真实的系统中，期望偏离这样的理想条件，因此，实验数据可能偏离理想方程。在本文中，我们提出了一种修改的组合动力学分析，通过使用经验方程，适合每一个f（α）的理想动力学模型中最广泛使用的文献，甚至其偏差产生的颗粒尺寸分布或不均匀性的颗粒形态。这里提出的程序允许在任何实验条件下获得的数据的组合动力学分析，而无需任何先前的动力学模型的假设，然后由反应。该程序已被验证与模拟和实验数据。
The combined kinetic analysis implies a simultaneous analysis of experimental data representative of the forward solid-state reaction obtained under any experimental conditions. The analysis is based on the fact that when a solid-state reaction is described by a single activation energy, preexponetial factor and kinetic model, every experimental T-alpha-d alpha/dt triplet should fit the general differential equation independently of the experimental conditions used for recording such a triplet. Thus, only the correct kinetic model would fit all of the experimental data yielding a unique activation energy and preexponential factor. Nevertheless, a limitation of the method should be considered; thus, the proposed solid- state kinetic models have been derived by supposing ideal conditions, such as unique particle size and morphology. In real systems, deviations from such ideal conditions are expected, and therefore, experimental data might deviate from ideal equations. In this paper, we propose a modification in the combined kinetic analysis by using an empirical equation that fits every f(alpha) of the ideal kinetic models most extensively used in the literature and even their deviations produced by particle size distributions or heterogeneities in particle morphologies. The procedure here proposed allows the combined kinetic analysis of data obtained under any experimental conditions without any previous assumption about the kinetic model followed by the reaction. The procedure has been verified with simulated and experimental data.