Facile and versatile preparation of silicalite-1 hollow structures using cotton threads as templates

In situ hydrothermal synthesis of various silicalite-1 hollow structures with different morphologies by using cotton threads as the templates was presented. It was found that the cotton thread was composed of many cotton fibers twisted together. By using loosely cotton thread, bunchy silicalite-1 hollow fibers with inner diameter close to the cotton fibers composed of the cotton thread were formed after burn-off of the template. Honeycomb silicalite-1 structure was prepared after three cycles of hydrothermal syntheses of the above bunchy silicalite-1 fibers. When tightly stretched single cotton thread was used, single silicalite-1 hollow fiber with inner diameter smaller than the outer diameter of the thread could be produced. Monolithic silicalite-1 structures were also prepared when the cotton threads were tightly stretched and also closely contacted in parallel with each other after three cycles of synthesis. Therefore, various silicalite-1 hollow structures could be easily and readily prepared by controlling the status of the cotton thread and the hydrothermal synthesis cycles.