Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
Sci Rep. 2013;3:2222. doi: 10.1038/srep02222.
Magnesiothermic reduction can directly convert SiO2 into Si nanostructures. Despite intense efforts, efficient fabrication of highly nanoporous silicon by Mg still remains a significant challenge due to the exothermic reaction nature. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, we demonstrate an effective route to convert diatom (SiO2) and SiO2/GeO2 into nanoporous Si and Si/Ge composite, respectively. Fusion of NaCl during the reaction consumes a large amount of heat that otherwise collapses the nano-porosity of products and agglomerates silicon domains into large crystals. Our methodology is potentially competitive for a practical production of nanoporous Si-based materials.
镁热还原可以直接将二氧化硅转化为硅纳米结构。尽管研究人员做了很多努力，但由于放热反应的性质，通过镁高效制备高度多孔硅仍然是一个重大挑战。通过使用食盐（NaCl）作为镁热还原的热捕集剂，我们展示了一种将硅藻（SiO2）和 SiO2/GeO2 分别转化为多孔硅和 Si/Ge 复合材料的有效途径。反应过程中 NaCl 的融合消耗了大量的热量，否则会使产物的纳米多孔结构塌陷，并将硅畴团聚成大晶体。我们的方法可能在实际生产多孔硅基材料方面具有竞争力。
