Augmenting H2 sensing performance of YSZ-based electrochemical gas sensors via the application of Au mesh and YSZ coating

The effect that the addition of Au mesh had on the gas sensitivity of a screen-printed Pt electrode patterned onto yttria-stabilised zirconia (YSZ) was investigated. By tuning the fabrication parameters, it was possible to engineer a selective high-temperature YSZ-based H2 sensor, with low sensitivity toward the following interfering gases: CO, CH4, C3H6, C3H8, NO and NO2. The gas sensitivity of the developed sensor was discussed with respect to sensing electrode composition, the floating nature of the electrode and the enhancement mechanism. The addition of an YSZ layer over a screen-printed Pt electrode together with Au mesh was found to confer significantly enhanced response/recovery characteristics. The YSZ-coated sensor was found to give excellent selectivity to H2 and stable sensing performance, after aging at 550 °C for three months. The aged sensor exhibited a linear sensitivity dependence on a logarithmic scale of H2 concentration ranging from 10 to 400 ppm in air under humid conditions.