A green and facile route to synthesize calcium silicate nanowires

Large-scale single crystalline calcium silicate nanowires have been synthesized via a simple and facile hydrothermal route using nanoscale SiO2 and CaO powders as the starting materials. Xonotlite [Ca6(Si6O17)(OH)2] nanowires were first achieved after hydrothermal treatment at 220 °C for 12 h. After being calcinated at 800 °C for 1 h, the Ca6(Si6O17)(OH)2 nanowires are completely transformed into β-CaSiO3 nanowires. The β-CaSiO3 nanowires have a diameter of 30-150 nm and a length of tens of micrometers. The hydrothermal conditions and the size of the raw materials play important roles on the size of the nanowires. A possible growth mechanism of the nanowires is also proposed.