Pt/nanostructured molybdenum oxide $\left({\text{MoO}}_3\right)/\text{SiC}$ Schottky diode based gas sensors were fabricated for hydrogen $\left({\text{H}}_2\right)$ gas sensing. Due to the enhanced performance, which is ascribed to the application of ${\text{MoO}}_3$ nanostructures, these devices were used in reversed bias. ${\text{MoO}}_3$ characterization by scanning electron microscopy showed morphology of randomly orientated nanoplatelets with thicknesses between 50 and 500 nm. An $\alpha \text{-}\beta$ mixed phase crystallographic structure of ${\text{MoO}}_3$ was characterized by x-ray diffraction. At $180°\text{C}$ , 1.343 V voltage shift in the reverse $I\text{-}V$ curve and a $\text{Pt}/{\text{MoO}}_3$ barrier height change of 20 meV were obtained after exposure to 1% ${\text{H}}_2$ gas in synthetic air.