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

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 H2 temperature programmed reduction with MS analysis (H2-TPR-MS). The results show that the nano-sized and irregularly-shaped 60-80 nm Mo particles were successfully synthesized at 600 °C for 2 h. Increasing the temperature to 650 °C-700 °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.