Nanocrystalline Gd1-xCaxFeO3 sensors for detection of methanol gas

The sol-gel method was used to prepare the nanocrystalline Gd1-xCaxFeO3 (x=0-0.4) powders. The XRD results showed that all the Gd1-xCaxFeO3 (x=0-0.4) compounds crystallized as perovskite phase with orthorhombic structure. The doping of Ca in GdFeO3 not only reduced the resistance, but also enhanced the response to methanol. The Gd0.9Ca0.1FeO3 showed the best response to methanol among Gd1-xCaxFeO3 sensors. Besides, it showed good selectivity to methanol among methanol, ethanol, CO and formaldehyde gases. The responses at 260 degrees C for Gd0.9Ca0.1FeO3-based sensor to 600 ppm methanol, ethanol and CO gases were 117.7, 72.7 and 31.9, respectively. Even at quite low gas concentrations, Gd0.9Ca0.1FeO3-based sensor had an obvious response. At 260 degrees C, the response of 1.54 was obtained to be 45 ppm methanol. The experimental results showed that nanocrystalline Gd0.9Ca0.1FeO3 based sensor can be used to detect methanol gas.