Synthesis of metastable monoclinic beta molybdenum trioxide nanoparticles by pulsed wire discharge

Metastable monoclinic molybdenum trioxide (β-MoO3) nanosized particles were synthesized by pulsed wire discharge in oxygen and nitrogen gases. The collected samples were characterized by X-ray diffraction to identify the phases, and field emission scanning electron microscopy was also used for the analysis of the particle size and its distribution. Different results were obtained by applying various conditions of the charged capacitor voltage (Vc) at 6, 4, and 3 kV and total gas pressures (P) of 100, 50, and 25 kPa, where the oxygen partial pressure of 25 kPa was always constant, and nitrogen gas was added to acquire the expected total pressure. The higher volume fraction of β-MoO3 was obtained at lower Vc and P (3 kV, 25 kPa). Inversely, the amount of -MoO3 and Mo increased at higher Vc and P. The geometric mean diameter (D1) of nanosized particles at every condition was determined under 50 nm.