A THICK-FILM HYDROGEN SENSOR-BASED ON A ZNO-MOO3 FORMULATION

A highly selective ZnO:MoO3 based thick-film hydrogen sensor has been developed. The surface morphological studies indicate that the average grain size increases with higher amounts of MoO3 in ZnO. It is observ ed that the sensitivity increases with the grain size. A possible work ing model for the sensor is postulated. MoO3 was mixed in ZnO in vario us weight percentages. These mixtures were screen printed on alumina s ubstrate. The sensors operate at an operating temperature of 450 degre es C and their conductance increases linearly with the square root of the concentration of H-2 gas in ambient air. The response time of thes e sensors is around 20 s.