▎ 摘　　要

This paper presents a comparative study on gas-sensing behavior of reduced graphene oxide (rGO) synthesized by chemical and green synthesis route. GO is synthesized by Hummers method and then reduced employing two reducing agents hydrazine hydrate [represented by (rGO)(1)] and l-citrulline [represented by (rGO)(2)]. Synthesized products were then obtained in the form of thin films, and tested for 10 ppm NO2 and CO at operating temperatures of 50, 100, and 150 degrees C. The green-synthesized reduced graphene oxide (rGO)(2) exhibits higher relative response of 254.7% as compared to conventionally synthesized (rGO)(1) (93.9%) and GO (22.7%) for 10 ppm NO2 at operating temperature of 150 degrees C. Furthermore, a switching of conductivity from usual p-type behavior to n-type on exposure of NO2 is observed at all operating temperatures (50, 100, and 150 degrees C) for GO, (rGO)(1), and (rGO)(2). The XRD, FTIR, and Raman confirm the oxidation and reduction process. (rGO)(2) shows high thermal stability as observed through TGA. FESEM and TEM images show wrinkled sheet structure for GO as well (rGO)(1) and (rGO)(2). The data observed from the characterization of resultant products have made it possible to explain better reduction of GO through green-reducing agent and enhanced gas-sensing performance of green-synthesized reduced graphene oxide.