Sensitive detection of ammonia by reduced graphene oxide/polypyrrole nanocomposites

• Drop cast in-situ method is used for the fabrication of thin film sensors of PPy and PPy/rGO composite material directly on the substrate.
• Samples are characterized by TEM, SEM, FTIR, XRD, UV–vis spectroscopy and are used for ammonia gas sensing.
• Sensitivity of PPy/rGO (PG5.0) increases with increasing concentration of rGO and it is 3 times higher than PPy.
• It is also observed that full recovery is possible after heating at ∼50 °C.

The polypyrrole (PPy) and its composite with reduced graphene oxide (rGO) are prepared by drop cast in-situ oxidative polymerization method. The fabricated thin film sensors are used for ammonia (NH3) gas sensing and are characterized by TEM, FEG-SEM, FT-IR, X-Ray diffraction and UV–vis methods. The PPy/rGO thin film sensors show very good sensing response to ammonia gas and are able to sense ammonia at 3 ppm. Sensitivity of these composites increases with increasing concentration of ammonia gas, and starts saturating at higher concentration. Sensitivity of PPy/rGO based sensor is nearly 3 times more than the PPy thin film sensor. It has been found that the sensors recovered fully after heating up to ∼50 °C.