Hydrothermal synthesis of h-MoO3 microrods and their gas sensing properties to ethanol

Abstract

Hexagonal molybdenum trioxide (h-MoO3) microrods were successfully synthesized via a novel and facile hydrothermal route from peroxomolybdate solution with the presence of NH4Cl as the mineralizer. A variety of the techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry combined with the thermal gravimetric analysis (DSC–TG) were used to characterize the product. The gas sensing test indicates that h-MoO3 microrods have a good response to 5–500ppm ethanol in the range of 273–380°C, and the optimum operating temperature is 332°C with a high sensitivity of 8.24 to 500ppm ethanol. Moreover, it also has a good selectivity toward ethanol gas if compared with other gases, such as ammonia, methanol and toluene. The sensing mechanism of h-MoO3 microrods to ethanol was also discussed.