The preparation and gas-sensing properties of NiFe2O4 nanocubes and nanorods

NiFe2O4 nanorods and nanocubes were prepared by a hydrothermal method without any surfactant for the first time. The length and diameter of the nanorods were about 1 μm and 30 nm, respectively; the side length of the nanocubes was about 60–100 nm. It was found that the sensor based on NiFe2O4 nanorods was relatively sensitive and selective to triethylamine. Especially, the sensitivity to 1 ppm triethylamine attained 7 when operating at 175 °C. On the other hand, the sensor based on NiFe2O4 nanocubes exhibited the opposite behavior; namely, the conductivity of the sensor increased in a reducing gas atmosphere.