Dipartimento di Ingegneria Elettrica e dell'Informazione, Politecnico di Bari, via Orabona 4, Bari, 70125, Italy.
Phys Chem Chem Phys. 2018 Jul 25;20(29):19560-19571. doi: 10.1039/c8cp02481b.
Solid-state reactivity is often studied by in situ experiments with a multi-technique approach, where complementarity of different probes is exploited. In situ data are usually analysed using a complex protocol: first the reaction model most suited to describe the specific solid-state reaction is chosen, second the reaction coordinate is obtained from the data, the order of reaction is then calculated by applying a specific kinetic equation, and finally kinetic parameters are obtained with an Arrhenius plot. The approach is both time consuming and subject to errors due to the arbitrariness of extraction of the reaction coordinate, typically from individual peak intensity variations during the reaction. In addition, application of the different kinetic equations to obtain the best fitting one is tedious and no general method to select the best model with an unbiased approach is available. Here we propose a new procedure based on principal component analysis to get kinetic information from in situ data, which simplifies and speeds up the process of kinetic parameter calculation from a three- to a two- or even a one-step form, reaching a high degree of automation and the ability to manage the huge amount of data produced by in situ multi-technique experiments. The new approach treats data as a whole, without biases introduced by manual methods of obtaining the reaction coordinate by peak intensity evaluation from individual patterns typical of the traditional approach. The procedure is described in its theoretical framework and applied to the formation of a molecular complex, monitored by in situ X-ray powder diffraction and Raman measurements.
固态反应通常通过采用多技术方法的原位实验进行研究，利用不同探针的互补性。原位数据通常使用复杂的方案进行分析：首先选择最适合描述特定固态反应的反应模型，其次从数据中获得反应坐标，然后通过应用特定的动力学方程计算反应级数，最后通过阿累尼乌斯图获得动力学参数。该方法既耗时又容易出错，因为反应坐标的提取具有任意性，通常是从反应过程中单个峰强度的变化中提取的。此外，应用不同的动力学方程来获得最佳拟合方程是繁琐的，并且没有一种通用的方法可以使用无偏方法选择最佳模型。在这里，我们提出了一种基于主成分分析的新方法，从原位数据中获取动力学信息，该方法将动力学参数计算的过程从三步简化和加速为两步甚至一步，达到了高度自动化的程度，并且能够处理原位多技术实验产生的大量数据。新方法将数据作为一个整体进行处理，避免了传统方法中通过从典型的单个图谱中评估峰强度来手动获取反应坐标所带来的偏差。该方法在其理论框架内进行了描述，并应用于通过原位 X 射线粉末衍射和拉曼测量监测的分子配合物的形成。
