A new approach for selective and ultrasensitive ammonia sensors by CuBr encapsulation in a mesoporous thin film for potential metabolic acidosis non-invasive monitoring

Abstract

Ammonia (NH3) can be considered as a chronic kidney disease bioindicator. The detection of skin emitted ammonia would allow a non-invasive medical monitoring of patients. Here, we develop a highly-sensitive and selective room-temperature ammonia microsensor based on copper-bromide (CuBr). The CuBr is impregnated in a mesoporous layer prepared by sol-gel synthesis and deposited by dip-coating on interdigitated platinum electrodes. The sensing performances are evaluated at 34 °C in dry air for short exposures (2 min) to ammonia. The sensor exhibits very high response (Rg/Ra of 4.5 for 200 ppb) with rapid recovery time and a very good selectivity. Moreover, the influence of humidity and temperature on the sensor performances are evaluated. The reported results demonstrate the possibility of developing an ultrasensitive gas sensor by a simple and low-cost approach consisting of the impregnation of the sensitive element in a mesoporous thin film.