Layered molybdenum disulfide MoS ₂ nanosheets for efficient ammonia gas sensing at room temperature

Abstract

In the current investigation, nanosheets of molybdenum disulfide (MoS 2 ) have been synthesized for room-temperature detection of ammonia (NH 3 ). MoS 2 nanosheets were successfully fabricated using liquid-phase exfoliation, and characterized using SEM, XRD, FTIR, AFM, and Raman spectroscopy. This chemiresistor gas sensor of pristine MoS 2 was subjected to a plethora of gases, including NO 2 , NH 3 , SO 2 , and N 2 O, at two concentration levels (27 and 100 ppm). The MoS 2 sensor preferentially detected NH 3 at room temperature while exhibiting p-type semiconducting behavior. It is interesting to note that the MoS 2 chemiresistive sensor exhibited decent sensitivity of ∼73, coupled with a response time of ∼74 s and a recovery time of ∼54 s, respectively, for the detection of 27 ppm NH 3 .