Preparation of Mo nanopowders through hydrogen reduction of a combustion synthesized foam-like MoO2 precursor

摘要

In this work, Nano-sized Mo particles were fabricated by solution combustion synthesis (SCS) followed by hydrogen reduction. A foam-like MoO2 precursor was first assembled using 20-30 nm nanoparticles generated by SCS. Subsequently, hydrogen reduction of the foam-like MoO2 precursor was undertaken to prepare the nano sized Mo particles. The reduction temperature of the final phases and morphologies of the Mo products were then systematically investigated. The hydrogen reduction mechanism of the foam-like MoO2 precursor was analyzed using thermogravimetry analysis (TG) and H-2 temperature programmed reduction with MS analysis (H-2-TPR-MS). The results show that the nano-sized and irregularly-shaped 60-80 nm Mo particles were successfully synthesized at 600 degrees C for 2 h. Increasing the temperature to 650 C-700 degrees C produced larger Mo particles due to sintering of the Mo powder at a higher reduction temperature. Additionally, a Mo2C impurity formed as a result of the carbon-thermal reaction between residual carbon and MoO2 in the presence of hydrogen.