Design and manufacture of ethanol gas nanobiosensor based on the GO/PANI/SnO2 composite

In this study, a nanobiosensor was fabricated for ethanol gas detection, and its electrochemical response to various concentrations of this gas was studied. In the first phase, in order to fabricate this nanobiosensor, the Graphene-Oxide/Polyaniline (GO/PANI) nano-composite was synthesized. Chemical composition, morphology and the structure of the nano-composites was studied by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The results show that the synthesis of graphene oxide is done correctly and the polyaniline particles are well bonded on the surface of the graphene oxide sheets as physically and chemically. Owning to the formation of the correct graphene-oxide/polyaniline nano-composite the analyzes indicate that the formation of polyaniline polymer chains on the surface of graphene oxide has led to the deformation of graphene sheets, which are normally flattened and uniformed sheets into the form of non-flattened and non-uniformed sheets. In the second phase, the formed nano-composite was placed on silver coated electrodes and then, by placing the nanoparticles of tin oxide, the nanobiosensors were sensitive toward the ethanol gas. Through the amperometric experiments, responsiveness and sensitivity and selectivity of the nanobiosensors to each of ethanol, carbon dioxide, methane and ammonia gases were measured and the results showed that the sensitivity of nanobiosensor fabricated to detection of the ethanol gas is acceptable. The results of the electrochemical tests showed that the nanobiosensors also have responded slightly to ammonia and methane.