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An alternative approach to kinetic analysis of temperature-programmed reaction data

机译：温度编程反应数据动力学分析的替代方法

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To date, kinetic computations have been carried out efficiently for a great variety of physico-chemical processes including crystallization, melting and solid-solid transitions. However, appropriate methods for the kinetic analysis of chemical reactions, especially multi-staged reactions, are currently lacking. Here we report on an alternative way of treating temperature-programmed reaction data using the reduction of iron(III) oxide as an example. The main principle in the suggested approach is to take into account every stage of the studied process, resulting in a system of kinetic differential equations. Kinetic parameters (activation energy and preexponential factors) are optimized for each of the stages, and cubic splines are used to approximate the conversion functions that reflect changes in reaction specific surface area throughout the process. The applicability of the suggested method has been tested on temperature-programmed reduction (TPR) data for iron(III) oxide samples produced from the original Fe2O3 powder by annealing it at 600, 700 and 800 degrees C. Results of kinetic analysis obtained at different temperature regimes demonstrate the good stability and performance of the method. Peculiarities of iron(III) oxide reduction have been revealed, depending on the stage and heating rate. The influence of material morphology on the reduction kinetics has been assessed by comparing preexponential factors corresponding to the first reduction stage. This approach allows a comparison of the structural characteristics of the materials based on the kinetic analysis of the TPR data. Using optimized conversion functions, the initial particle size distribution has been reproduced. Theoretically found particle size distribution was found to correlate well with the experimental distribution obtained via laser diffraction.
机译：迄今为止，动力学计算已经有效地适用于多种物理化学过程，包括结晶，熔化和固 - 固转变的情况下进行。然而，对于化学反应的动力学分析适当的方法，特别是多级反应，目前缺乏。在这里，我们使用铁（III）氧化物的还原，例如处理温度编程的反应数据的另一种方法提出报告。在建议的方法的主要原理是考虑到所研究的过程的每个阶段，产生的动力学微分方程的系统。动力学参数（活化能和指前因子）针对每个阶段的优化，和三次样条被用来近似反映在整个过程中反应的比表面积的变化的转换函数。在不同的所提出的方法的适用性上程序升温还原过测试（TPR）获得通过在600，700和800℃的动力学分析的结果退火它从原始的Fe2O3粉末生产氧化铁样品的数据温度制度表明了该方法的良好的稳定性和性能。铁（III）氧化物还原的特殊性已经发现，这取决于阶段和加热速率。在还原动力学材料形态学的影响已经通过比较对应于第一减速级指前因子评估。这种方法允许基于所述TPR数据的动力学分析的材料的结构特性的比较。使用优化的转换函数，初始颗粒尺寸分布已经被再现。从理论上求出的粒径分布，发现通过激光衍射所获得的实验分布良好关联。

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  • 来源
    《RSC Advances》 |2018年第6期|共10页
  • 作者

    Portnyagin A. S.; Golikov A. P.; Drozd V. A.; Avramenko V. A.;

  • 作者单位

    Russian Acad Sci Inst Chem Dept Sorpt Proc Far Eastern Branch Pr 100 Letiya Vladivostoka Vladivostok Russia;

    Russian Acad Sci Inst Chem Dept Sorpt Proc Far Eastern Branch Pr 100 Letiya Vladivostoka Vladivostok Russia;

    Far Eastern Fed Univ Sci Educ Ctr Nanotechnol Sukhanova Str 8 Vladivostok Russia;

    Russian Acad Sci Inst Chem Dept Sorpt Proc Far Eastern Branch Pr 100 Letiya Vladivostoka Vladivostok Russia;

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  • 正文语种 eng
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