Sensitive detection of H₂S based on Ce doped ZnCo₂O₄ hollow microspheres at low working temperature

In order to develop a highly efficient H₂S gas sensor at low working temperature, in this work, a kind of novel Ce-doped ZnCo₂O₄ hollow microspheres (Ce/ZnCo₂O₄ HMSs) were successfully synthesized using a template-free one-pot method, showing a sensitive response toward H₂S. 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 ZnCo₂O₄ doped with 6 mol% Ce had the highest response to 20 ppm H₂S 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 ZnCo₂O₄. The prepared Ce/ZnCo₂O₄ HMS sensor in response to H₂S 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 H₂S 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.