Comparative study of miracle leaf extracts reduced graphene oxide (m-rGO) and chemically synthesized graphene oxide (GO) as methanol gas sensor

A novel, green, bio-inspired synthesis of miracle leaf extracts reduced graphene oxide (m-rGO) nanosheets was explored. Here, graphene oxide (GO) was prepared using modified Hummers method from graphite powder and then reduced by miracle leaf extracts to produce m-rGO. The prepared m-rGO and chemically prepared GO was characterized by scanning electron microscopy (SEM), powder x-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, Raman Spectroscopy and UV–Visible Spectroscopy. The XRD, FTIR, and Raman confirm the oxidation and reduction process. SEM and TEM images showed wrinkled sheet structure for green-synthesized reduced graphene oxides. The synthesized m-rGO products were investigated as a methanol gas sensor at ambient temperature using laboratory-made sensor setup. The sensing characteristics were monitored by measuring the change in electrical resistivity on exposure to methanol vapor at different concentrations. It is observed that the electrical response and % sensitivity of m-rGO toward methanol vapor is found to be a highly sensitive (254.7) than that of GO (27.7). The basic mechanism of the interaction between methanol and GO is believed to be hydrogen bonding and π–π interaction. To the best of our knowledge, no study has been conducted on miracle leaf extracts reduced graphene oxide (m-rGO) using this environment friendly green method for application of methanol gas sensor.