Ultrafast microwave-assisted solvothermal synthesis and characterization of near-spherical CoSb3 nanopowders.

Near-spherical shape CoSb₃ nanopowders have been rapidly synthesized by a microwave-assisted solvothermal method. The use of a microwave-assisted solvothermal method saves 99% of the dwell time compared to conventional solvothermal and hydrothermal methods. The effects of composition and processing parameters such as temperature and dwell time on the formation process of CoSb₃ nanopowders were investigated. It is found almost pure CoSb₃ can be synthesized at 280 °C with n (Co²⁺):n (Sb³⁺) = 1:3.5 for 20 min. The Rietveld refinement result indicates that the amount of CoSb₃ phase is 95%. The microstructure characterization and analysis results show that the final products consist mainly of nearly spherical particles with an average diameter of approximately 33 nm. Meanwhile, high-density grain boundaries and dislocations are also found in the as-obtained CoSb₃ nanopowders, which can contribute to the decrease of thermal conductivity by phonon scatterings. [ABSTRACT FROM AUTHOR]