Sensitive detection of H 2 S based on Ce doped ZnCo 2 O 4 hollow microspheres at low working temperature.

In order to develop a highly efficient H ₂ S gas sensor at low working temperature, in this work, a kind of novel Ce-doped ZnCo ₂ O ₄ hollow microspheres (Ce/ZnCo ₂ O ₄ HMSs) were successfully synthesized using a template-free one-pot method, showing a sensitive response toward H ₂ S. The microstructure and morphology of the material were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The gas-sensing performance of the composite was investigated, showing that the ZnCo ₂ O ₄ doped with 6 mol% Ce had the highest response to 20 ppm H ₂ S at a low operating temperature of 160 °C with a response value of 67.42, which was about 2 times higher than that of original ZnCo ₂ O ₄ . The prepared Ce/ZnCo ₂ O ₄ HMS sensor in response to H ₂ S exhibited a linear range of 0.1-200 ppm with a low detection limit of 0.1 ppm under the conditions of ambient humidity of 45% and ambient temperature of 20 °C. Meanwhile, it also possessed good selectivity, repeatability and reproducibility. The response value of the sensor decreased by 5.32% after 7 months of continuous monitoring of H ₂ S in an atmospheric environment of a pig farm, indicating that the sensor had a long-term stability and continuous service life with important application prospects.