Synthesis and low-temperature sensing property of the porous ZnCo₂O₄ nanosheets

Hydrogen sulfide even with low concentration in environment is very pernicious to the health, Therefore, the design of gas sensors for detecting H₂S is highly desirable. In this work, porous spinel ZnCo₂O₄ nanosheets (NSs) were synthesized via a hydrothermal method and followed by the thermal treatment. Structural characterizations indicate that the porous NSs are composed of ~ 14 nm interconnected ZnCo₂O₄ nanoparticles. The porous spinel ZnCo₂O₄ NSs exhibit enhanced H₂S sensing performance in comparison to Co₃O₄ NSs. The detection limit of the porous ZnCo₂O₄ NSs is down to 100 ppb H₂S with a sensor response value of 1.32 even at relatively low operating temperature of 120 °C. Furthermore, the porous ZnCo₂O₄ NSs have fascinating selectivity and good long-term stability and relatively rapid response time. The gas sensing mechanism of the ZnCo₂O₄ NSs gas sensor is also discussed in terms of the effects of oxygen vacancies. In view of the exciting gas-sensing properties and facile preparation method, the porous ZnCo₂O₄ NSs are ideal candidates for the H₂S sensors.