THICK-FILM HYDROGEN SENSOR

A thick-film SnO2-based hydrogen gas sensor has been developed. The fa bricated device is found to be very sensitive for hydrogen gas and is capable of detecting hydrogen in the order of a few ppm (less than or equal to 100) concentration. The effects of temperature and the amount of catalytic palladium doping in SnO2 towards the hydrogen sensitivit y of the sensor have been studied. The peak sensitivity of the sensor towards hydrogen is found to be at an operating temperature of 350 deg rees C and the optimum catalytic content in the SnO2 layer is 0.25 wt. % palladium. A possible reaction scheme for the interaction of hydroge n with the SnO2 surface in air is also proposed.