Martell Sarah A, Yan Maximilian, Coridan Robert H, Stone Kevin H, Patwardhan Siddharth V, Dasog Mita
Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, NS B3H 4R2, Canada.
Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK.
Nanoscale Horiz. 2024 Sep 23;9(10):1833-1842. doi: 10.1039/d4nh00244j.
The magnesiothermic reduction of SiO is an important reaction as it is a bulk method that produces porous Si for a wide range of applications directly from SiO. While its main advantage is potential tunability, the reaction behavior and final product properties are heavily dependent on many parameters including feedstock type. However, a complete understanding of the reaction pathway has not yet been achieved. Here, using X-ray diffraction analysis, for the first time, various pathways through which the magnesiothermic reduction reaction proceeds were mapped. Further, the key parameters and conditions that determine which pathways are favored were determined. It was discovered that the reaction onset temperatures can be as low as 348 ± 7 °C, which is significantly lower when compared to previously reported values. The onset temperature is dependent on the size of Mg particles used in the reaction. Further, MgSi was identified as a key intermediate rather than a reaction byproduct during the reduction process. Its rate of consumption is determined by the reaction temperature which needs to be >561 °C. These findings can enable process and product optimization of the magnesiothermic reduction process to manufacture and tune porous Si for a range of applications.
SiO的镁热还原反应是一个重要的反应，因为它是一种直接从SiO制备用于广泛应用的多孔硅的体相方法。虽然其主要优点是具有潜在的可调性，但反应行为和最终产物性能在很大程度上取决于许多参数，包括原料类型。然而，尚未完全了解反应途径。在此，首次使用X射线衍射分析绘制了镁热还原反应进行的各种途径。此外，确定了决定哪些途径更受青睐的关键参数和条件。发现反应起始温度可低至348±7°C，与先前报道的值相比显著更低。起始温度取决于反应中使用的Mg颗粒的尺寸。此外，MgSi被确定为还原过程中的关键中间体而非反应副产物。其消耗速率由需要>561°C的反应温度决定。这些发现能够实现镁热还原过程的工艺和产物优化，以制造和调整用于一系列应用的多孔硅。
