Chiang Mai Journal of Science

  In this work, ethanol sensing films were prepared by spin-coating of PdO/WO₃ nanorods pasted onto Al₂O₃ substrates interdigitated with Au electrodes and tested towards 50-2000 ppm C₂H₅OH at different operating temperatures ranging from 150–350°C. It was found that the C₂H₅OH responses of PdO-loaded WO₃ sensors monotonically increased with increasing operating temperature to 350°C and increased greatly with increasing PdO-loading level up to 1.0 wt%. In particular, the optimal 1.0 wt% PdO-loaded sensor exhibited an ultra-high response of 1.52 ×10⁴ to 2000 ppm C₂H₅OH at 350ºC with a short response time of ~3 s. In addition, PdO–loaded WO₃ sensing films displayed high ethanol selectivity against CO, NO₂, NH₃ and H₂S. Therefore, PdO-loaded WO₃ nanorods sensors prepared by the precipitation and impregnation methods are promising for highly sensitive and selective for ethanol sensing.