Hydrothermal Synthesis of Quartz Nanocrystals

This paper describes for the first time a chemical method for the preparation for nanocrystalline quartz. Submicron quartz powders are initially produced in hydrothermal reactions where soluble silica precursors precipitate as pure crystalline silica. To yield nanocrystalline material these particles can be purified and size selected by dialysis, filtration, and centrifugation. Transmission electron microscopy and X-ray diffraction illustrate that the product is pure phase α-quartz, consisting of isolated (i.e., nonaggregated) nanocrystals. Depending on the size selection method, crystallites with average sizes of 10 to 100 nanometers can be recovered.