NH_3 Sensing Properties of CNT-WO_3 Sensors

CNT-WO3 indirectly heated gas sensors were fabricated with carbon nanotubes as the dopant. The as-grown carbon nanotube was purified by mixed acid oxidation process and WO3 nanopowders were prepared by a chemical precipitation method. FT-IR, TEM, TG-DSC and XRD were introduced to characterize them. The gas sensitive performance of the made sensors was measured at room temperature. The experimental results show the gas sensitivity of the carbon nanotube-doped sensor is far higher than that of a pure WO3 sensor and the 0.8wt% carbon nanotube-doped sensor has the highest sensitivity. In addition, the carbon nanotube-doped sensor is superior for its lowest detectable concentration, wide detectable range and excellent gas selectivity. It is an ideal NH3 sensor.