Preparation of reduced graphene oxide decorated two-dimensional WSe2 nanosheet sensor for efficient detection of ethanol gas

To protect human health and the environment, sensitive detection of volatile organic compounds (VOCs) with high selectivity and an ultrafast response/recovery time is required. Exhaled high concentrations of ethanol may be a biomarker of fatty liver disease and a sign of intoxication. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are novel two-dimensional materials which are gaining significant attention in sensing applications. Herein, we have developed an ethanol sensor based on 2D WSe2 nanosheets (NSs) and WSe2/rGO hybrid through a solvothermal approach. The structure, elemental composition, morphology, size, and specific area of WSe2 and WSe2/rGO NSs were characterized by XRD, EDS, SEM, TEM, and N2-adsorption-desorption isothermal analysis (BET). From the sensing investigations, we have observed that the WSe2/rGO hybrid sensor had the highest response value of 5.5–100 ppm ethanol at 180 °C which is 2.75-fold higher than the WSe2 NSs at 220 °C to relative humidity (55% RH). Furthermore, trace ethanol exhibits significant selectivity compared to other interfering gases such as methanol, acetone, toluene, isopropyl alcohol, and ammonia. The heterojunction model between rGO and WSe2 were responsible for the improved gas sensing capability. The gas sensing properties and mechanisms of the as-obtained materials in air and ethanol are demonstrated and discussed in detail. These findings have the potential to give a suitable material for gas sensing applications and have been recommended for testing in other domains. In this regard, we affirm that the WSe2/rGO hybrid could be a potential candidate for designing and constructing flexible ethanol gas sensors. The proposed methodology can be used for chemical and biochemical sensing.