▎ 摘　　要

Present work describes NO2 gas sensing of Ag:ZnO (Ag = 1, 3, 5, 10 wt%) and reduced graphene oxide (rGO) functionalized Ag:ZnO nanocomposites. Herein, Ag:ZnO nanocomposites were synthesized by one pot hydro -thermal method followed by graphene oxide synthesis by modified Hummers method and Ag:ZnO/rGO nano -composites synthesis by chemical route. The structural, optical, surface morphological and elemental analysis of the synthesized nanocomposites were carried by X-ray diffraction (XRD), Raman Spectroscopy, UV-Visible spectroscopy, Field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The NO2 gas sensing results showed highest sensor response for 3 wt% Ag:ZnO nanocomposites. Further the enhancement in the sensor performance was noted on functionalization with rGO. Highest sensor response (Rg/Ra = 4.5), fast response (91 s), recovery time (270 s) and good selectivity toward NO2 gas at moderate operating temperature was achieved for the optimized composition. Further, the real time monitoring of NO2 gas was carried out using Arduino based SMS alert system.