Selective synthesis of 3C-SiC hollow nanospheres and nanowires

3C-SiC hollow nanospheres with a high yield (similar to 80%) were prepared by using SiCl4, CBr3H, and Na-K alloy at 130 degrees C for 15 h and a subsequent HClO4 treatment process at 180 degrees C. These SiC hollow nanospheres have diameters in the range of 80-420 nm and an average shell thickness of similar to 15 nm. High resolution transmission electron microscopy investigation reveals that these hollow spherical nanocrystals have rough surfaces, indicating they are composed of nanoparticles. When Na-K alloy was substituted by Na (or K) and in the mean time the temperature was set at 240 degrees C while keeping other conditions unchanged, a large quantity of randomly distributed and highly crystalline SiC nanowires with diameters ranging from 30 to 50 nm and lengths up to several tens of micrometers also can be produced. The possible formation mechanisms of the products with distinct dimensions were briefly discussed. The method used here generally could be used to synthesize other carbides at low temperature.