A facile microwave route for fabrication of NiO/rGO hybrid sensor with efficient CO₂ and acetone gas sensing performance using clad modified fiber optic method

The hybrid Nickel oxide/Reduced graphene oxide (NiO/rGO) nanostructure was prepared through facile one-pot microwave irradiation technique. X-ray Diffraction (XRD) and Transmission electronic microscope (TEM) results suggests the formation of the cubic structure of NiO with well uniform spherical shaped morphology. The morphological analysis reveals the formation of NiO/rGO nanostructures with the size of about 50−60 nm. Moreover, NiO nanoparticles are covered by rGO sheets thoroughly that shows the good formation of the binary nanocomposite. The function groups on the surface of composite nanostructures were studied using Fourier transform infrared spectroscopy (FT-IR) analysis. The N₂ adsorption-desorption analysis represents that the surface area of NiO/rGO (112.4 m²/g), which is beneficial for developing the efficient gas sensing property of as-prepared nanostructure. The gas sensing ability of both NiO and NiO/rGO sensors was evaluated by using a clad modified fiber optic gas sensor setup. The CO₂ and acetone gases were used as the target gas to detect the gas sensing ability of as-prepared NiO and NiO/rGO nanostructures. The results demonstrate that NiO/rGO sensor has good sensing response towards CO₂ gas such as high sensitivity (83 counts/ppm), rapid response (16 s) and recovery time (22 s). The possible sensing mechanism of the proposed sensor is also discussed in detail.