Nanostructured tetragonal crystal NdVO$_4$ for the detection of liquefied petroleum gas

Semiconductive nanometer-sized NdVO$_4$ was synthesized by a solution combustion reaction of Nd(NO$_3$)$_3\cdot$6H$_2$O, V(NO$_3$)$_3$ and urea as a fuel. The process was a convenient, environment friendly, inexpensive and efficient preparation method for the NdVO4 nanomaterial. Effects of the 800$^\circ$ C calcining temperature on the phase constituents was characterized by TG-DTA, X-ray diffraction (XRD), which was used to confirm the material's structure. The as-prepared samples were further characterized by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM), to depict the crystallite microstructure. Conductance responses of the nanocrystalline NdVO$_4$ thick film were measured by exposing the film to reducing gases like acetone, ethanol, ammonia (NH$_3$), and liquefied petroleum gas (LPG). It was found that the sensors exhibited various sensing responses to these gases at different operating temperatures. Furthermore, the sensor exhibited a fast response and a good recovery. The results demonstrated that NdVO$_4$ can be used as a new type of gas-sensing material which has a high sensitivity and good selectivity to Liquefied petroleum gas (LPG).