Gas sensing characteristics of composite NiO/Al2O3 for 2-chloroethanol at low temperature

Composite NiO/Al2O3 was prepared by calcination of Ni/Al hydrotalcite for gas sensing materials. Methods of XRD, SEM, TEM, EDS and BET were used to analyze the structure, composition and morphology of the composite oxide. It was found that the sample was composed of crystal NiO and amorphous Al2O3. Furthermore, the composite NiO/Al2O3 has smaller grain size and larger surface area than that of pure NiO obtained by the same process. In the gas sensing experiments, the sensor based on NiO/Al2O3 showed superior gas sensing response and selectivity to 2-chloroethanol at low temperature. The response (Rg/Ra) of NiO/Al2O3 was 6.8-20 ppm 2-chloroethanol at 160 °C. The role of Al2O3 in the composite was also discussed.