Sulfide Sensor Based on Room-Temperature Phosphorescence of PbO/SiO2 Nanocomposite

A new strategy for the fabrication of a sulfide sensor based on room-temperature phosphorescence (RTP) of PbO/SiO2 nanocomposite is proposed. The PbO/SiO2 phosphor is prepared by a sol−gel method, and it produces highly emissive broad-band RTP under the irradiation of UV light. The phosphorescence intensity of PbO/SiO2 nanocomposite could be quenched by sulfide, and the response behavior of the sensor is dependent on the value of pH of the solution. At pH 11.0, the sensor exhibits a linear response toward sulfide at the concentration range from 2.67 to 596 μM. The detection limit for the sensor is estimated to be 0.138 μM (3 σ), and the precision for five replication detections of 6 μM sulfide is 1.82% (relative standard deviation). The color of the sensor and its phosphorescence intensity change obviously and could be observed with the naked eye when there was continuous addition of sulfide from the concentration of 50 μM. The phosphorescence intensity of quenched PbO/SiO2 phosphor can be recovered when dipping it into H2O2 solution, which demonstrates a good sulfide response characteristic of reusability. Furthermore, the sensor is easy to apply for trace hydrogen sulfide determination in the gas phase.