High-performance room temperature NH₃ gas sensors based on polyaniline-reduced graphene oxide nanocomposite sensitive membrane

In this study, polyaniline-reduced graphene oxide (PANI-rGO) nanocomposite films were used as sensitive membranes in NH₃ gas sensors operated at room temperature (300 K). The responsivity and response speed of the PANI-rGO NH₃ gas sensors were improved by homogeneously distributing PANI nanospheres on both surfaces of rGO nanosheets. The optimal weight ratio was 125 which was obtained by changing the weight ratio of PANI/rGO in the NH₃ gas sensors. The NH₃ gas sensors based on rGO and PANI sensitivity membranes had responsivities of 0.5% and 8.3%, whereas the recovery times were 8.0 and 48.0 min, respectively. The optimal responsivity and recovery time of these PANI-rGO NH₃ gas sensors operated at room temperature under a 15-ppm NH₃ gas environment were 13.0% and 22.1 min, respectively. However, because the responsivity of a rGO sensing membrane was considerably less than that of a PANI sensing membrane, the responsivity of the PANI-rGO NH₃ gas sensors was reduced by incorporating more rGO content. The lowest detectable NH₃ gas concentration of the PANI-rGO NH₃ gas sensors was 0.3 ppm.