A room-temperature ammonia gas sensor based on the h-MoO3@Graphene composite film with fast response time.

Abstract

The release of ammonia (NH3) in industry or daily life is harmful to human health. A gas sensor was developed using h-MoO3 nanorods and graphene film to detect and eliminate this. The h-MoO3 nanorods were first synthesized by chemical bath deposition using ammonium molybdate tetrahydrate (NH4)6Mo7O24•4H2O and HNO3 and then deposited on the graphene film transferred to SiO2/Si substrate by electrochemical bubbling method. Subsequently, gas-sensitive h-MoO3@graphene composite films were prepared and analyzed using Raman, XRD, SEM, and UV-vis. The gas sensor's performance was evaluated to detect NH3 at a room temperature concentration range of 1-60 ppm. Compared with graphene, the conductivity of the composite film with 10 mg/ml h-MoO3 nanorods was increased by 40% and the sensitivity increased by 10 times. The sensor h-MoO3@G-10 showed the best sensing performance to 1 ppm NH3. Sensor sensitivity, response and recovery time are 1.1%, 46.8 s and 17.8 s.