Facile synthesis of ultrafine rGO/WO3 nanowire nanocomposites for highly sensitive toxic NH3 gas sensors

[Display omitted] •Nanocomposites of rGO and WO3 nanowires were hydrothermally synthesized.•The rGO/WO3 nanocomposites showed excellent sensing performance with theoretical detection limit of 138 ppb.•Gas-sensing mechanism was discussed based on the p-n heterojunction.•The rGO/WO3 nanocomposites are capable for monitoring highly toxic NH3 gas in air. We introduce a facile and scalable synthesis of rGO/WO3 nanocomposites by hydrothermal method for gas sensing applications. The characterization of rGO/WO3 nanocomposites by some advanced techniques such as scanning electron microscopy, high resolution transmission electron microscopy and Raman spectroscopy revealed that high quality rGO/WO3 nanocomposites included single crystal WO3 nanowires (average diameter of 10 nm) entangled by thin rGO layers. Sensing measurements demonstrated that the rGO/WO3 nanocomposite-based sensor can detect highly toxic NH3 gas at low concentrations ranging from 20 ppm to 500 ppm and fulfills practical applications. The developed gas sensors based on rGO/WO3 nanocomposites have significant application prospects in environment pollution monitoring at detection limit of about 138 ppb. We also discussed the gas sensing mechanism of the rGO/WO3 nanocomposites based on the p-n junction.