Synthesis and characterization of ZnCo2O4 nanostructures and investigation of their morphologies effect on gas sensing performance

In the present work, ZnCo2O4 nanostructures were successfully synthesized using hydrothermal method. In order to investigate the morphology of the nanostructures on their gas sensing performance, we used three different concentrations of urea (5, 10, 15 mmol) in growth process which caused three different morphologies of ZnCo2O4. The structure and morphology of the products were respectively analyzed by XRD and SEM. To study the gas sensing parameters, the nanostructures were dispersed in ethanol and then settled on a gold coated glass electrode. The results showed that the sensor including ZnCo2O4 nanostructure grown under 5 mmol urea has 9.5 response, 25 seconds response time, and 49 seconds recovery time for 100 ppm acetone gas at 240 oC work temperature. In addition, we observed that this sensor has a good selectivity for acetone gas in compare to ethanol, methanol, benzene, and toluene gases. The high response of ZnCo2O4 flower shaped microrod grown under 5 mmol urea could be related to its large specific area and rod morphology.