Chemical combustion synthesis of CeO₂–ZnO nanocomposite and its application in ethanol sensing

Metal oxide-based nanocomposites has been regarded as a useful tool for sensors technology to detect various hazardous gases at low concentrations. In this work, the CeO₂–ZnO composite was successfully synthesized using a simple chemical combustion method. The synthesized samples were characterized by employing different characterization techniques. The results demonstrated that the cubic fluorite phase of CeO₂ and the hexagonal wurtzite phase of ZnO have been obtained while the CeO₂–ZnO composite showed a mixed phase of CeO₂ and ZnO. The morphology of the CeO₂–ZnO products has a nanoporous structure. The well-defined structure of the CeO₂–ZnO nanocomposite was confirmed by the HR-TEM. Furthermore, gas sensing study showed that CeO₂–ZnO nanocomposite exhibited enhanced sensing properties toward ethanol at an operating temperature of 275 ℃. The gas sensitivity value was 61.75% toward 24 ppm ethanol. This could be attributed to the formation of the n–n heterojunction between CeO₂ and ZnO which enhances conductivity value to give more sensitivity.