Novel selective sensors based on carbon nanotube films for hydrogen detection

Novel resistive gas sensors based on single-walled carbon nanotubes (SWNTs) as an active sensing element have been evaluated for hydrogen detection. Sensor films were fabricated by airbrushing SWNT dispersions on alumina substrates. The employed SWNT materials were either chemically functionalized with Pd or sputtered with Pd to enhance their sensitivity to hydrogen. Sensors were characterized by dc electrical measurements in nitrogen and air atmosphere. The response to hydrogen and the cross sensitivity to gases such as ammonia, toluene and octane were studied. Aged Pd-functionalized SWNT films exhibited good sensitivity and selectivity to hydrogen at room temperature. The effect of aging, thermal treatments and the employed carrier gas were also investigated.