Enhanced nitrogen oxide sensing performance based on tin-doped tungsten oxide nanoplates by a hydrothermal method

The great demand for gas sensors in practical applications has stimulated tremendous attention in this area due to its important significance in real life. A facile synthesis of WO₃ nanoplates and their subsequent Sn doping strategy by using a hydrothermal method was investigated to enhance gas sensing performance for NO₂ gas, one of the gases toxic to human beings and the environment. Various techniques were used to characterize all the products. The morphology characterizations demonstrated that all the samples exhibited a similar nanoplate structure with or without Sn doping. The gas sensing properties of the sensors based on different doping concentrations (0, 1, 2 and 5wt%) have been systematically investigated. The sensor based on the 2wt% Sn-doped WO₃ nanoplates showed the maximum response to NO₂ (55-100ppb NO₂). Furthermore, the introduction of Sn ions into the sensing materials of WO₃ resulted in shorter response and recovery times. This finding could be attributed to the increased number of oxygen vacancies on the surface of the sensing material and the resistance of the gas sensors. The results provide a new doping strategy to fabricate high performance NO₂ gas sensors.