Sensing characteristics of double layer film of ZnO

Pure ZnO powder was made by chemical precipitation. ZnO-based gas sensing materials and Al2O3-based catalysts doped with a noble metal were prepared with impregnation. Gas sensitivity of ZnO single layer and double layer film gas sensors was measured in static state. It can be shown from experimental results that the gas sensitivity and selectivity of ZnO gas sensor can be improved by doping noble metal and using noble metal catalyst coating.