Microwave-Assisted Hydrothermal Synthesis of α-MoO₃

Abstract—Orthorhombic molybdenum trioxide α-MoO₃ was obtained by microwave-assisted hydrothermal treatment of an aqueous solution of peroxomolybdic and oxalic acids taken in Mo : H₂C₂O₄ · 2H₂O molar ratio of 1 : (0.25‒1). The structural details of formation of α-MoO₃ were studied by powder X-ray diffraction, Raman spectroscopy, and pycnometric density determination. The effect of the synthesis conditions on the morphology and textural characteristics of molybdenum trioxide powders was studied by scanning electron microscopy and low-temperature nitrogen adsorption. It was found that the molar ratio of the components in the reaction mixture is the crucial factor for the synthesis of MoO₃. The band gap for the synthesized samples was found from the optical absorption spectra.