Synthesis of transition metals doped CeO2 nanorods as an Ethanol sensor

The MX%-CeO2 (M=Zr4+, V3+) nanorods were synthesized via hydrothermal method. The field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to investigate the surface morphology and know the structural properties of the nanorods. The nanorods were used to make sensors and their sensitivity be tested for volatile organic compounds including methanol, acetone, ethanol and 2-propanol. The results showed that Zr4+ and V3+ dopant ions play a vital role in the structure and the size of rods. According to the sensing results these nanorods exhibited stronger and faster response to ethanol gas than the bare CeO2. While the CeO2 nanorods showed the sensitivity of 4.5 units for 340ppm ethanol concentration, sensitivity of doped samples with V3+ and Zr4+ ions increased to 10.32 and 5.66 units, respectively. The sensitivity enhancement described by the larger modulation of the conduction channel width and interfacial potential barrier height. According to the results, Zr20%-CeO2 and V1%-CeO2 sensors were more sensitive and selective to ethanol, compared to the other samples.