A selective and sensitive hydrogen (H-2) sensor capable of working at a high operating temperature was developed by using a pair of metal-oxide-based SEs formed on a yttria-stabilized zirconia (YSZ) tube, operating as a mixed-potential type sensor. The utilization of SnO2 (+30 wt.% YSZ) electrode together with NiO-TiO2 electrode configured as a combined-type sensor, successfully diminished the response of the examined interfering gases (especially propene), while maintaining high response toward H-2 at an operating temperature of 600 degrees C under humid operating conditions. The developed sensor exhibited quick response to 100 ppm H-2, as the 90% response time was observed to be 9s. The sensing performance of the combined-type sensor was barely affected by changes in water vapor concentration within the range of 1-4 vol.%, suggesting the resilience of the sensor to function in realistic working conditions. This sensor exhibited a linear relationship between sensitivity and H-2 concentration on a logarithmic scale. (C) 2012 Elsevier Ltd. All rights reserved.