Development of micro hydrogen gas sensor with SnO2–Ag2O–PtOx composite using MEMS process

Thick film H2 sensors were fabricated using SnO2 loaded with Ag2O and PtOx. The nano-crystalline powders of SnO2–Ag2O–PtOx composites synthesized by a sol–gel method were screen printed on alumina substrates. The fabricated sensors were tested against gases like H2, CH4, C3H8, C2H5OH and SO2. The composition that gave the highest response to H2 was SnO2:Ag2O:PtOx = 93:5:2 in wt% ratio. The composite material was found to be sensitive to H2, with minor interference of other gases, at a working temperature of 125 °C. H2 gas as low as 100 ppm could be detected by the present fabricated sensor. It was found that the sensor based on the SnO2–Ag2O–PtOx nano-crystalline system exhibited high-performance, high selectivity and very short response time to H2 at ppm level. These characteristics make the sensor to be a promising candidate for detecting low concentrations of H2.