| 摘 要： | The sol-gel method was used to prepare the nanocrystalline Gd_(1–x)Ca_xFeO_3 (x=0–0.4) powders. The XRD results showed that all the Gd_(1–x)Ca_xFeO_3 (x=0–0.4) compounds crystallized as perovskite phase with orthorhombic structure. The doping of Ca in GdFeO_3 not only reduced the resistance, but also enhanced the response to methanol. The Gd_(0.9)Ca_(0.1)FeO_3 showed the best response to methanol among Gd_(1–x)Ca_xFeO_3 sensors. Besides, it showed good selectivity to methanol among methanol, ethanol, CO and formaldehyde gases. The responses at 260 oC for Gd_(0.9)Ca_(0.1)FeO_3-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, Gd_(0.9)Ca_(0.1)FeO_3-based sensor had an obvious response. At 260 °C, the response of 1.54 was obtained to be 45 ppm methanol. The experimental results showed that nanocrystalline Gd_(0.9)Ca_(0.1)FeO_3 based sensor can be used to detect methanol gas.
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