Green synthesis and possible applications of MoO2 nanoparticles

Abstract

This work reports the green hydrothermal synthesis of MoO2 nanoparticles and their applications in Cr6+ adsorbent and MoO3 precursor. A green hydrothermal method, which was based on the autoclave-sealed reactions of (NH4)6Mo7O24•4H2O and glucose in acetic acid (12.5 vol%) aqueous solution at 190 °C for 12 hours, was proposed for the synthesis of MoO2 nanoparticles. The characterization results from X-ray diffraction and transmission electron microscopy suggested the successful preparation of pure monoclinic phase MoO2 (m-MoO2) nanoparticles. The m-MoO2 nanoparticles exhibited a good adsorption capacity for Cr6+ (for example, 300 mg of m-MoO2 nanoparticles can adsorb the whole Cr6+ in 300 mL of 50 mg/L K2Cr2O7 aqueous solution after mixing for 280 minutes). Besides, the m-MoO2 nanoparticles can be completely converted to orthorhombic phase MoO3 nanoflakes after heating in air at 400 °C for 5 hours.