Understanding the High Sensitivity of Parallel WO3 Sensor Toward NO2 Gas at Low Temperature

Tungsten trioxide (WO3-x) with different morphologies was synthesized by hydrothermal method. Using a pair of Pt electrodes and Al2O3 ceramics tube as a substrate, NO2 sensing properties of the WO3 products were measured at different working temperatures. And the high sensing properties at low working temperature were also investigated. The results showed that the sensitivity of WO3 product is strongly dependent on morphology and structure. The parallel circuit mode also plays an important role in the NO2 sensing characteristics. The low working temperature can be attributed to the competitive reaction between O2 and NO2 gas. The parallel mode may increase the lifetime of sensor.