Synthesis and growth of rodlike and spherical nanostructures CoSb3 via ethanol sol-gel method

The synthesis and growth of rodlike and spherical nanostructures of CoSb3 compounds using an ethanol sol-gel method are reported. The characterization results indicate that the molar ratios of Sb/Co and C6H8O7/Co affect the phase composition, and only when Sb/Co = 6 and C6H8O7/Co = 4, the obtained powder is a single-phase CoSb3 compound. The crystalline morphology of CoSb3 compounds is composed of spherical nanostructures about 50 nm in diameter and nanorods about 30 nm in diameter and 100-200 nm in length. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) prove that nanorods grow along the [110] direction. The rodlike CoSb3 compound is ultimately produced due to the differences in growth rates between the crystal faces. The formation of a carbonyl coordination compound Co-2(CO)(8) between the Co atoms reduced by H-2 and the CO formed by citric acid decomposition causes the differences in the growth rate. In the local spaces without CO, the CoSb3 nuclei become spherical.