Detection of elemental mercury in flue-gas by a chemiresistive SnS–SnO2 ccomposite ssensor

Due to bioaccumulation and globe atmosphere migration of elemental mercury, the source emission control of elemental mercury has attracted great attention. The elemental mercury sensor paves a new way for the detection of elemental mercury in the atmosphere. We introduced an elemental mercury sensor with high response and fast response-recovery features to elemental mercury based on the SnS–SnO2 composite. The mixed stacking SnS nanosheets and SnO2 nano-octahedrons composite were synthesized. The sensor showed a desired response of 14 to 3 mg/m3 elemental mercury with an ultra-fast response time of 40 s and a recovery time of 30 s. Besides, the sensor exhibits a high selectivity of various common interfering gases in the flue-gas like CO, SO2, NH3, and NO2. The detailed sensing mechanism was discussed at the molecular level by the energy band theory. The outstanding sensing properties of the SnS–SnO2 composite based elemental mercury sensor could be applied for the fast detection of elemental mercury in the flue gas.