A HIGHLY SENSITIVE AND SELECTIVE HYDROGEN GAS SENSOR FROM THICK ORIENTED FILMS OF MOS2

A new process is developed to fabricate a highly sensitive and selecti ve hydrogen sensor by depositing a partially crystalline and highly or iented film of MoS2 from its single layer suspension on an alumina sub strate. When these films are promoted with some catalysts selected fro m Pt-group metals (Pt, Pd, Ru or any combination of these metals) they exhibit a high sensitivity and selectivity to hydrogen gas. Unlike ot her metal oxide sensors which are sensitive to many reducing and oxidi zing gases and operate at a temperature of 350 degrees C or higher, th is sensor is highly selective to hydrogen gas and its operating temper ature is from 25 to 150 degrees C. The lower operating temperature enh ances safety when dealing with hydrogen gas. The sensor response to hy drogen at 120 degrees C is linear in concentration from 30 to 10(4) pp m with a 10 to 30 second response time and a 45 to 90 second recovery time. Above 10(4) ppm the sensor is still linear but the slope of cond uctance versus hydrogen concentration changes.