Ultraselective and ultrasensitive detection of trimethylamine using MoO3 nanoplates prepared by ultrasonic spray pyrolysis

An ultraselective and ultrasensitive trimethylamine (TMA) sensor was achieved using MoO3 nanoplates-prepared by ultrasonic spray pyrolysis followed by a heat treatment at 450 °C. The small and thin MoO3 nanoplates with gas-accessible structures showed an unusually high response to 5 ppm TMA (ratio of resistance to air and gas = 373.74) at 300 °C with detection limit as low as 45 ppb. Moreover, the ratios of the cross-responses to interfering gases (i.e., 5 ppm C2H5OH, CO, CH4, C3H8, H2, and NO2) to the response to 5 ppm TMA were extremely low (0.008-0.016). The source of the ultraselective and highly sensitive detection of TMA with negligible interference from other gases is discussed with respect to the acid/base properties, size, and morphology of the MoO3 sensing materials.